Author: "P. Abraham" / Topic: nuclear & particles physics - Searchworks@Jio Institute Digital Library Search Results

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1. Measurement of the top-quark mass using a leptonic invariant mass in pp collisions at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adachi, S, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, CF, Anders, JK, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aperio Bella, L, Araque, JP, Araujo Ferraz, V, Araujo Pereira, R, Arcangeletti, C, and Arce, ATH
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, Hadron-Hadron Scattering, Top Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A measurement of the top-quark mass (mt) in the tt¯ → lepton + jets channel is presented, with an experimental technique which exploits semileptonic decays of b-hadrons produced in the top-quark decay chain. The distribution of the invariant mass mℓμ of the lepton, ℓ (with ℓ = e, μ), from the W-boson decay and the muon, μ, originating from the b-hadron decay is reconstructed, and a binned-template profile likelihood fit is performed to extract mt. The measurement is based on data corresponding to an integrated luminosity of 36.1 fb−1 of s = 13 TeV pp collisions provided by the Large Hadron Collider and recorded by the ATLAS detector. The measured value of the top-quark mass is mt = 174.41 ± 0.39 (stat.) ± 0.66 (syst.) ± 0.25 (recoil) GeV, where the third uncertainty arises from changing the Pythia8 parton shower gluon-recoil scheme, used in top-quark decays, to a recently developed setup. [Figure not available: see fulltext.].
Published: 2023

2. Two-particle Bose–Einstein correlations in pp collisions at s=13 TeV measured with the ATLAS detector at the LHC

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adachi, S, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexandre, D, Alexopoulos, T, Alfonsi, A, Alhroob, M, Ali, B, Alimonti, G, Alison, J, Alkire, SP, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alvarez Estevez, M, Álvarez Piqueras, D, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, CF, Anders, JK, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aperio Bella, L, Arabidze, G, Araque, JP, Araujo Ferraz, V, and Araujo Pereira, R
Subjects: Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: This paper presents studies of Bose–Einstein correlations (BEC) in proton–proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrated luminosities of 151 μ b- 1 and 8.4 nb- 1, respectively. The BEC are measured for pairs of like-sign charged particles, each with | η| < 2.5 , for two kinematic ranges: the first with particle pT> 100 MeV and the second with particle pT> 500 MeV. The BEC parameters, characterizing the source radius and particle correlation strength, are investigated as functions of charged-particle multiplicity (up to 300) and average transverse momentum of the pair (up to 1.5 GeV). The double-differential dependence on charged-particle multiplicity and average transverse momentum of the pair is also studied. The BEC radius is found to be independent of the charged-particle multiplicity for high charged-particle multiplicity (above 100), confirming a previous observation at lower energy. This saturation occurs independent of the transverse momentum of the pair.
Published: 2022

3. Constraints on Higgs boson properties using WW∗(→eνμν)jj production in 36.1fb-1 of s=13 TeV pp collisions with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, Arcangeletti, C, Arce, ATH, and Arguin, J-F
Subjects: Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: This article presents the results of two studies of Higgs boson properties using the WW∗(→ eνμν) jj final state, based on a dataset corresponding to 36.1 fb - 1 of s=13 TeV proton–proton collisions recorded by the ATLAS experiment at the Large Hadron Collider. The first study targets Higgs boson production via gluon–gluon fusion and constrains the CP properties of the effective Higgs–gluon interaction. Using angular distributions and the overall rate, a value of tan (α) = 0.0 ± 0.4 (stat.) ± 0.3 (syst.) is obtained for the tangent of the mixing angle for CP-even and CP-odd contributions. The second study exploits the vector-boson fusion production mechanism to probe the Higgs boson couplings to longitudinally and transversely polarised W and Z bosons in both the production and the decay of the Higgs boson; these couplings have not been directly constrained previously. The polarisation-dependent coupling-strength scale factors are defined as the ratios of the measured polarisation-dependent coupling strengths to those predicted by the Standard Model, and are determined using rate and kinematic information to be aL=0.91-0.18+0.10(stat.)-0.17+0.09(syst.) and aT= 1.2 ± 0.4 (stat.)-0.3+0.2(syst.). These coupling strengths are translated into pseudo-observables, resulting in κVV=0.91-0.18+0.10(stat.)-0.17+0.09(syst.) and ϵVV=0.13-0.20+0.28 (stat.)-0.10+0.08(syst.). All results are consistent with the Standard Model predictions.
Published: 2022

4. The ATLAS inner detector trigger performance in pp collisions at 13 TeV during LHC Run 2

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, Arcangeletti, C, Arce, ATH, and Arguin, J-F
Subjects: Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: The design and performance of the inner detector trigger for the high level trigger of the ATLAS experiment at the Large Hadron Collider during the 2016–2018 data taking period is discussed. In 2016, 2017, and 2018 the ATLAS detector recorded 35.6fb-1, 46.9fb-1, and 60.6fb-1 respectively of proton–proton collision data at a centre-of-mass energy of 13 TeV. In order to deal with the very high interaction multiplicities per bunch crossing expected with the 13 TeV collisions the inner detector trigger was redesigned during the long shutdown of the Large Hadron Collider from 2013 until 2015. An overview of these developments is provided and the performance of the tracking in the trigger for the muon, electron, tau and b-jet signatures is discussed. The high performance of the inner detector trigger with these extreme interaction multiplicities demonstrates how the inner detector tracking continues to lie at the heart of the trigger performance and is essential in enabling the ATLAS physics programme.
Published: 2022

5. Performance of the ATLAS Level-1 topological trigger in Run 2

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Hoffman, AC Abusleme, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Arcangeletti, C, Arce, ATH, Arguin, J-F, and Argyropoulos, S
Subjects: Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: During LHC Run 2 (2015–2018) the ATLAS Level-1 topological trigger allowed efficient data-taking by the ATLAS experiment at luminosities up to 2.1× 1034 cm- 2s- 1, which exceeds the design value by a factor of two. The system was installed in 2016 and operated in 2017 and 2018. It uses Field Programmable Gate Array processors to select interesting events by placing kinematic and angular requirements on electromagnetic clusters, jets, τ-leptons, muons and the missing transverse energy. It allowed to significantly improve the background event rejection and signal event acceptance, in particular for Higgs and B-physics processes.
Published: 2022

6. Configuration and performance of the ATLAS b-jet triggers in Run 2

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Alison, J, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Pereira, R Araujo, Arcangeletti, C, and Arce, ATH
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: Several improvements to the ATLAS triggers used to identify jets containing b-hadrons (b-jets) were implemented for data-taking during Run 2 of the Large Hadron Collider from 2016 to 2018. These changes include reconfiguring the b-jet trigger software to improve primary-vertex finding and allow more stable running in conditions with high pile-up, and the implementation of the functionality needed to run sophisticated taggers used by the offline reconstruction in an online environment. These improvements yielded an order of magnitude better light-flavour jet rejection for the same b-jet identification efficiency compared to the performance in Run 1 (2011–2012). The efficiency to identify b-jets in the trigger, and the conditional efficiency for b-jets that satisfy offline b-tagging requirements to pass the trigger are also measured. Correction factors are derived to calibrate the b-tagging efficiency in simulation to match that observed in data. The associated systematic uncertainties are substantially smaller than in previous measurements. In addition, b-jet triggers were operated for the first time during heavy-ion data-taking, using dedicated triggers that were developed to identify semileptonic b-hadron decays by selecting events with geometrically overlapping muons and jets.
Published: 2021

7. Erratum to: Measurement of hadronic event shapes in high-pT multijet final states at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, and Araujo Pereira, R
Subjects: Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: An error in the normalization of the Aplanarity and D-parameter has been found. Insufficient precision on the eigenvalue calculation can cause λ3 to be negative, exclusively in two-jet events, yielding an underestimation of the inclusive two-jet cross section.
Published: 2021

8. Search for resonances decaying into photon pairs in 139 fb(-1) of pp collisions at root s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Akesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Alvarez Estevez, M, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, and Arcangeletti, C
Subjects: Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Published: 2021

9. Erratum to: Measurement of light-by-light scattering and search for axion-like particles with 2.2 nb−1 of Pb+Pb data with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, and Araujo Pereira, R
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: One correction is noted for the paper, which does not affect the results reported. The right panel of figure 9 is corrected as it contained the “internal” label, giving the misleading impression on the credibility of the figure.
Published: 2021

10. Search for resonances decaying into photon pairs in 139 fb−1 of pp collisions at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: Searches for new resonances in the diphoton final state, with spin 0 as predicted by theories with an extended Higgs sector and with spin 2 using a warped extra-dimension benchmark model, are presented using 139 fb−1 of s=13 TeV pp collision data collected by the ATLAS experiment at the LHC. No significant deviation from the Standard Model is observed and upper limits are placed on the production cross-section times branching ratio to two photons as a function of the resonance mass.
Published: 2021

11. Search for dark matter in events with missing transverse momentum and a Higgs boson decaying into two photons in pp collisions at √s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, Arcangeletti, C, Arce, ATH, and Arguin, JF
Subjects: Hadron-Hadron scattering, Nuclear & Particles Physics, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: A search for dark-matter particles in events with large missing transverse momentum and a Higgs boson candidate decaying into two photons is reported. The search uses 139 fb−1 of proton-proton collision data collected at s = 13 TeV with the ATLAS detector at the CERN LHC between 2015 and 2018. No significant excess of events over the Standard Model predictions is observed. The results are interpreted by extracting limits on three simplified models that include either vector or pseudoscalar mediators and predict a final state with a pair of dark-matter candidates and a Higgs boson decaying into two photons. [Figure not available: see fulltext.]
Published: 2021

12. Search for dark matter produced in association with a single top quark in √s=13 TeV pp collisions with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, AA, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, CA, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, KA, Alberghi, GL, Albert, J, Verzini, MJA, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, EA, Estevez, MA, Alviggi, MG, Coutinho, YA, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SPAD, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JAA, Aparo, MA, Bella, LA, Aranzabal, N, Ferraz, VA, Pereira, RA, and Arcangeletti, C
Subjects: Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: This paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a, which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at s=13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb - 1. No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered.
Published: 2021

13. Erratum to: Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: In this article the title was incorrectly given as ‘Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at √s = 13 with the ATLAS detector’ but should have been ‘Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at √s = 13 TeV with the ATLAS detector’. The original article has been corrected.
Published: 2021

14. Search for dark matter produced in association with a single top quark in s=13 TeV pp collisions with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: This paper presents a search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudoscalar mediator, a, which decays into the dark-matter particles. Processes where the pseudoscalar mediator is produced in association with a single top quark in the 2HDM+a model are explored for the first time at the LHC. Several final states which include either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum are considered. The analysis is based on proton–proton collision data collected with the ATLAS experiment at s=13 TeV during LHC Run 2 (2015–2018), corresponding to an integrated luminosity of 139 fb - 1. No significant excess above the Standard Model predictions is found. The results are expressed as 95% confidence-level limits on the parameters of the signal models considered.
Published: 2021

15. Search for dark matter in events with missing transverse momentum and a Higgs boson decaying into two photons in pp collisions at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, Arcangeletti, C, Arce, ATH, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron scattering, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A search for dark-matter particles in events with large missing transverse momentum and a Higgs boson candidate decaying into two photons is reported. The search uses 139 fb−1 of proton-proton collision data collected at s = 13 TeV with the ATLAS detector at the CERN LHC between 2015 and 2018. No significant excess of events over the Standard Model predictions is observed. The results are interpreted by extracting limits on three simplified models that include either vector or pseudoscalar mediators and predict a final state with a pair of dark-matter candidates and a Higgs boson decaying into two photons. [Figure not available: see fulltext.]
Published: 2021

16. Erratum to: Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at √s = 13 TeV with the ATLAS detector (The European Physical Journal C, (2021), 81, 7, (600), 10.1140/epjc/s10052-021-09344-w)

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: In this article the title was incorrectly given as ‘Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at √s = 13 with the ATLAS detector’ but should have been ‘Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at √s = 13 TeV with the ATLAS detector’. The original article has been corrected.
Published: 2021

17. Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Abusleme Hoffman, AC, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arena, E, and Arguin, JF
Subjects: hep-ex, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ
Published: 2021

18. Measurement of single top-quark production in association with a W boson in the single-lepton channel at s=8TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adachi, S, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexandre, D, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Estevez, M Alvarez, Piqueras, D Álvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, CF, Anders, JK, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Bella, L Aperio, and Arabidze, G
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: The production cross-section of a top quark in association with a W boson is measured using proton–proton collisions at s=8TeV. The dataset corresponds to an integrated luminosity of 20.2fb-1, and was collected in 2012 by the ATLAS detector at the Large Hadron Collider at CERN. The analysis is performed in the single-lepton channel. Events are selected by requiring one isolated lepton (electron or muon) and at least three jets. A neural network is trained to separate the tW signal from the dominant tt¯ background. The cross-section is extracted from a binned profile maximum-likelihood fit to a two-dimensional discriminant built from the neural-network output and the invariant mass of the hadronically decaying W boson. The measured cross-section is σtW=26±7pb, in good agreement with the Standard Model expectation.
Published: 2021

19. Discovering dark matter at the LHC through its nuclear scattering in far-forward emulsion and liquid argon detectors

Author: Batell, Brian, Feng, Jonathan L, Ismail, Ahmed, Kling, Felix, Abraham, Roshan Mammen, and Trojanowski, Sebastian
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Astronomical sciences, Particle and high energy physics
Abstract: The LHC may produce light, weakly interacting particles that decay to dark matter, creating an intense and highly collimated beam of dark matter particles in the far-forward direction. We investigate the prospects for detecting this dark matter in two far-forward detectors proposed for a future forward physics facility: FASERν2, a 10-ton emulsion detector, and FLArE, a 10- to 100-ton LArTPC. We focus here on nuclear scattering, including elastic scattering, resonant pion production, and deep inelastic scattering, and devise cuts that efficiently remove the neutrino-induced background. In the invisibly decaying dark photon scenario, DM-nuclear scattering probes new parameter space for dark matter masses 5 MeV mχ 500 MeV. When combined with the DM-electron scattering studied previously, FASERν2 and FLArE will be able to discover dark matter in a large swath of the cosmologically favored parameter space with MeV mχ GeV.
Published: 2021

20. Measurements of sensor radiation damage in the ATLAS inner detector using leakage currents

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Abusleme Hoffman, AC, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Physical Sciences, Radiation damage to detector materials, Detector modelling and simulations I, hep-ex, Engineering, Nuclear & Particles Physics, Physical sciences
Abstract: Non-ionizing energy loss causes bulk damage to the silicon sensors of the ATLAS pixel and strip detectors. This damage has important implications for data-taking operations, charged-particle track reconstruction, detector simulations, and physics analysis. This paper presents simulations and measurements of the leakage current in the ATLAS pixel detector and semiconductor tracker as a function of location in the detector and time, using data collected in Run 1 (2010–2012) and Run 2 (2015–2018) of the Large Hadron Collider. The extracted fluence shows a much stronger |z|-dependence in the innermost layers than is seen in simulation. Furthermore, the overall fluence on the second innermost layer is significantly higher than in simulation, with better agreement in layers at higher radii. These measurements are important for validating the simulation models and can be used in part to justify safety factors for future detector designs and interventions.
Published: 2021

21. Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (tt¯ Z) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on s=13 TeV proton–proton collision data with an integrated luminosity of 139 fb - 1, recorded from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. The inclusive cross section is measured to be σtt¯Z= 0.99 ± 0.05 (stat.) ±0.08 (syst.) pb, in agreement with the most precise theoretical predictions. The differential measurements are presented as a function of a number of kinematic variables which probe the kinematics of the tt¯ Z system. Both absolute and normalised differential cross-section measurements are performed at particle and parton levels for specific fiducial volumes and are compared with theoretical predictions at different levels of precision, based on a χ2/ ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.
Published: 2021

22. Jet energy scale and resolution measured in proton–proton collisions at s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, and Pereira, R Araujo
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: Jet energy scale and resolution measurements with their associated uncertainties are reported for jets using 36–81 fb- 1 of proton–proton collision data with a centre-of-mass energy of s=13 TeV collected by the ATLAS detector at the LHC. Jets are reconstructed using two different input types: topo-clusters formed from energy deposits in calorimeter cells, as well as an algorithmic combination of charged-particle tracks with those topo-clusters, referred to as the ATLAS particle-flow reconstruction method. The anti-kt jet algorithm with radius parameter R= 0.4 is the primary jet definition used for both jet types. This result presents new jet energy scale and resolution measurements in the high pile-up conditions of late LHC Run 2 as well as a full calibration of particle-flow jets in ATLAS. Jets are initially calibrated using a sequence of simulation-based corrections. Next, several in situ techniques are employed to correct for differences between data and simulation and to measure the resolution of jets. The systematic uncertainties in the jet energy scale for central jets (| η| < 1.2) vary from 1% for a wide range of high-pT jets (2502.5TeV). The relative jet energy resolution is measured and ranges from (24 ± 1.5)% at 20 GeV to (6 ± 0.5)% at 300 GeV.
Published: 2021

23. Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at √s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, AA, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, CA, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, KA, Alberghi, GL, Albert, J, Verzini, MJA, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, EA, Estevez, MA, Alviggi, MG, Coutinho, YA, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SPAD, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JAA, Aparo, MA, Bella, LA, Aranzabal, N, Ferraz, VA, Pereira, RA, and Arcangeletti, C
Subjects: Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (tt¯ Z) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on s=13 TeV proton–proton collision data with an integrated luminosity of 139 fb - 1, recorded from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. The inclusive cross section is measured to be σtt¯Z= 0.99 ± 0.05 (stat.) ±0.08 (syst.) pb, in agreement with the most precise theoretical predictions. The differential measurements are presented as a function of a number of kinematic variables which probe the kinematics of the tt¯ Z system. Both absolute and normalised differential cross-section measurements are performed at particle and parton levels for specific fiducial volumes and are compared with theoretical predictions at different levels of precision, based on a χ2/ ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.
Published: 2021

24. Jet energy scale and resolution measured in proton–proton collisions at √s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, AA, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, CA, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, KA, Alberghi, GL, Albert, J, Verzini, MJA, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, EA, Estevez, MA, Alviggi, MG, Coutinho, YA, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SPAD, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JAA, Aparo, MA, Bella, LA, Aranzabal, N, Ferraz, VA, and Pereira, RA
Subjects: Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Jet energy scale and resolution measurements with their associated uncertainties are reported for jets using 36–81 fb- 1 of proton–proton collision data with a centre-of-mass energy of s=13 TeV collected by the ATLAS detector at the LHC. Jets are reconstructed using two different input types: topo-clusters formed from energy deposits in calorimeter cells, as well as an algorithmic combination of charged-particle tracks with those topo-clusters, referred to as the ATLAS particle-flow reconstruction method. The anti-kt jet algorithm with radius parameter R= 0.4 is the primary jet definition used for both jet types. This result presents new jet energy scale and resolution measurements in the high pile-up conditions of late LHC Run 2 as well as a full calibration of particle-flow jets in ATLAS. Jets are initially calibrated using a sequence of simulation-based corrections. Next, several in situ techniques are employed to correct for differences between data and simulation and to measure the resolution of jets. The systematic uncertainties in the jet energy scale for central jets (| η| < 1.2) vary from 1% for a wide range of high-pT jets (2502.5TeV). The relative jet energy resolution is measured and ranges from (24 ± 1.5)% at 20 GeV to (6 ± 0.5)% at 300 GeV.
Published: 2021

25. Measurements of sensor radiation damage in the ATLAS inner detector using leakage currents

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, Abouzeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, and Pereira, RA
Subjects: Radiation damage to detector materials, Detector modelling and simulations I, hep-ex, Nuclear & Particles Physics, Physical Sciences, Engineering
Abstract: Non-ionizing energy loss causes bulk damage to the silicon sensors of the ATLAS pixel and strip detectors. This damage has important implications for data-taking operations, charged-particle track reconstruction, detector simulations, and physics analysis. This paper presents simulations and measurements of the leakage current in the ATLAS pixel detector and semiconductor tracker as a function of location in the detector and time, using data collected in Run 1 (2010–2012) and Run 2 (2015–2018) of the Large Hadron Collider. The extracted fluence shows a much stronger |z|-dependence in the innermost layers than is seen in simulation. Furthermore, the overall fluence on the second innermost layer is significantly higher than in simulation, with better agreement in layers at higher radii. These measurements are important for validating the simulation models and can be used in part to justify safety factors for future detector designs and interventions.
Published: 2021

26. Measurement of single top-quark production in association with a W boson in the single-lepton channel at √s=8TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, AA, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adachi, S, Adam, L, Bourdarios, CA, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, KA, Alberghi, GL, Albert, J, Verzini, MJA, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexandre, D, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Estevez, MA, Piqueras, DÁ, Alviggi, MG, Coutinho, YA, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SPAD, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, CF, Anders, JK, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JAA, Bella, LA, and Arabidze, G
Subjects: Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The production cross-section of a top quark in association with a W boson is measured using proton–proton collisions at s=8TeV. The dataset corresponds to an integrated luminosity of 20.2fb-1, and was collected in 2012 by the ATLAS detector at the Large Hadron Collider at CERN. The analysis is performed in the single-lepton channel. Events are selected by requiring one isolated lepton (electron or muon) and at least three jets. A neural network is trained to separate the tW signal from the dominant tt¯ background. The cross-section is extracted from a binned profile maximum-likelihood fit to a two-dimensional discriminant built from the neural-network output and the invariant mass of the hadronically decaying W boson. The measured cross-section is σtW=26±7pb, in good agreement with the Standard Model expectation.
Published: 2021

27. Evidence for Higgs boson decays to a low-mass dilepton system and a photon in pp collisions at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Hoffman, AC Abusleme, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Arcangeletti, C, Arce, ATH, Arena, E, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: A search for the Higgs boson decaying into a photon and a pair of electrons or muons with an invariant mass mℓℓ
Published: 2021

28. A search for the decays of stopped long-lived particles at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Abusleme Hoffman, AC, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arena, E, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron scattering, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A search for long-lived particles, which have come to rest within the ATLAS detector, is presented. The subsequent decays of these particles can produce high-momentum jets, resulting in large out-of-time energy deposits in the ATLAS calorimeters. These de- cays are detected using data collected during periods in the LHC bunch structure when collisions are absent. The analysed dataset is composed of events from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy of s = 13 TeV and recorded by the ATLAS experiment during 2017 and 2018. The dataset used for this search corresponds to a total live time of 579 hours. The results of this search are used to derive lower limits on the mass of gluino R-hadrons, assuming a branching fraction B(g~→qq¯χ10) = 100%, with masses of up to 1.4 TeV excluded for gluino lifetimes of 10−5 to 103 s. [Figure not available: see fulltext.]
Published: 2021

29. Determination of the parton distribution functions of the proton from ATLAS measurements of differential W± and Z boson production in association with jets

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron scattering, QCD, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: This article presents a new set of proton parton distribution functions, ATLASepWZVjet20, produced in an analysis at next-to-next-to-leading order in QCD. The new data sets considered are the measurements of W+ and W− boson and Z boson production in association with jets in pp collisions at s = 8 TeV performed by the ATLAS experiment at the LHC with integrated luminosities of 20.2 fb−1 and 19.9 fb−1, respectively. The analysis also considers the ATLAS measurements of differential W± and Z boson production at s = 7 TeV with an integrated luminosity of 4.6 fb−1 and deep-inelastic-scattering data from e±p collisions at the HERA accelerator. An improved determination of the sea-quark densities at high Bjorken x is shown, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range x ≲ 0.02 found by previous ATLAS analyses. [Figure not available: see fulltext.]
Published: 2021

30. The ATLAS Fast TracKer system

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Albicocco, P, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Alison, J, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Anderson, JT, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, and Pereira, R Araujo
Subjects: Engineering, Electrical Engineering, Electronics, Sensors and Digital Hardware, Physical Sciences, Networking and Information Technology R&D (NITRD), Modular electronics, Online farms and online filtering, Pattern recognition, cluster finding, calibration and fitting methods, Trigger concepts and systems, Nuclear & Particles Physics, Physical sciences
Abstract: The ATLAS Fast TracKer (FTK) was designed to provide full tracking for the ATLAS high-level trigger by using pattern recognition based on Associative Memory (AM) chips and fitting in high-speed field programmable gate arrays. The tracks found by the FTK are based on inputs from all modules of the pixel and silicon microstrip trackers. The as-built FTK system and components are described, as is the online software used to control them while running in the ATLAS data acquisition system. Also described is the simulation of the FTK hardware and the optimization of the AM pattern banks. An optimization for long-lived particles with large impact parameter values is included. A test of the FTK system with the data playback facility that allowed the FTK to be commissioned during the shutdown between Run 2 and Run 3 of the LHC is reported. The resulting tracks from part of the FTK system covering a limited η-ϕ region of the detector are compared with the output from the FTK simulation. It is shown that FTK performance is in good agreement with the simulation.
Published: 2021

31. Measurements of differential cross-sections in four-lepton events in 13 TeV proton-proton collisions with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron scattering, Lepton production, proton-proton scattering, Beyond Standard Model, Branching fraction, hep-ex, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: Measurements of four-lepton differential and integrated fiducial cross-sections in events with two same-flavour, opposite-charge electron or muon pairs are presented. The data correspond to 139 fb−1 of s = 13 TeV proton-proton collisions, collected by the ATLAS detector during Run 2 of the Large Hadron Collider (2015–2018). The final state has contributions from a number of interesting Standard Model processes that dominate in different four-lepton invariant mass regions, including single Z boson production, Higgs boson production and on-shell ZZ production, with a complex mix of interference terms, and possible contributions from physics beyond the Standard Model. The differential cross-sections include the four-lepton invariant mass inclusively, in slices of other kinematic variables, and in different lepton flavour categories. Also measured are dilepton invariant masses, transverse momenta, and angular correlation variables, in four regions of four-lepton invariant mass, each dominated by different processes. The measurements are corrected for detector effects and are compared with state-of-the-art Standard Model calculations, which are found to be consistent with the data. The Z → 4ℓ branching fraction is extracted, giving a value of (4.41 ± 0.30) × 10−6. Constraints on effective field theory parameters and a model based on a spontaneously broken B − L gauge symmetry are also evaluated. Further reinterpretations can be performed with the provided information. [Figure not available: see fulltext.]
Published: 2021

32. Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √(s)=13 TeV

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, Arcangeletti, C, Arce, ATH, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Synchrotrons and Accelerators, Physical Sciences, Gaseous detectors, Muon spectrometers, Resistive-plate chambers, Trigger detectors, Engineering, Nuclear & Particles Physics, Physical sciences
Abstract: The ATLAS experiment at the Large Hadron Collider (LHC) employs a trigger system consisting of a first-level hardware trigger (L1) and a software-based high-level trigger. The L1 muon trigger system selects muon candidates, assigns them to the correct LHC bunch crossing and classifies them into one of six transverse-momentum threshold classes. The L1 muon trigger system uses resistive-plate chambers (RPCs) to generate the muon-induced trigger signals in the central (barrel) region of the ATLAS detector. The ATLAS RPCs are arranged in six concentric layers and operate in a toroidal magnetic field with a bending power of 1.5 to 5.5 Tm. The RPC detector consists of about 3700 gas volumes with a total surface area of more than 4000 m2. This paper reports on the performance of the RPC detector and L1 muon barrel trigger using 60.8 fb-1 of proton-proton collision data recorded by the ATLAS experiment in 2018 at a centre-of-mass energy of 13 TeV. Detector and trigger performance are studied using Z boson decays into a muon pair. Measurements of the RPC detector response, efficiency, and time resolution are reported. Measurements of the L1 muon barrel trigger efficiencies and rates are presented, along with measurements of the properties of the selected sample of muon candidates. Measurements of the RPC currents, counting rates and mean avalanche charge are performed using zero-bias collisions. Finally, RPC detector response and efficiency are studied at different high voltage and front-end discriminator threshold settings in order to extrapolate detector response to the higher luminosity expected for the High Luminosity LHC.
Published: 2021

33. Search for supersymmetry in events with four or more charged leptons in 139 fb−1 of s = 13 TeV pp collisions with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron scattering, Supersymmetry, Beyond Standard Model, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A search for supersymmetry in events with four or more charged leptons (electrons, muons and τ-leptons) is presented. The analysis uses a data sample corresponding to 139 fb−1 of proton-proton collisions delivered by the Large Hadron Collider at s = 13 TeV and recorded by the ATLAS detector. Four-lepton signal regions with up to two hadronically decaying τ-leptons are designed to target several supersymmetric models, while a general five-lepton signal region targets any new physics phenomena leading to a final state with five charged leptons. Data yields are consistent with Standard Model expectations and results are used to set upper limits on contributions from processes beyond the Standard Model. Exclusion limits are set at the 95% confidence level in simplified models of general gauge-mediated supersymmetry, excluding higgsino masses up to 540 GeV. In R-parity-violating simplified models with decays of the lightest supersymmetric particle to charged leptons, lower limits of 1.6 TeV, 1.2 TeV, and 2.5 TeV are placed on wino, slepton and gluino masses, respectively. [Figure not available: see fulltext.]
Published: 2021

34. Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at s=13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: The results of a search for gluino and squark pair production with the pairs decaying via the lightest charginos into a final state consisting of two W bosons, the lightest neutralinos (χ~10), and quarks, are presented: the signal is characterised by the presence of a single charged lepton (e± or μ±) from a W boson decay, jets, and missing transverse momentum. The analysis is performed using 139 fb- 1 of proton–proton collision data taken at a centre-of-mass energy s=13 delivered by the Large Hadron Collider and recorded by the ATLAS experiment. No statistically significant excess of events above the Standard Model expectation is found. Limits are set on the direct production of squarks and gluinos in simplified models. Masses of gluino (squark) up to 2.2 (1.4) are excluded at 95% confidence level for a light χ~10.
Published: 2021

35. Determination of the parton distribution functions of the proton from ATLAS measurements of differential W± and Z boson production in association with jets

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arguin, JF, and Argyropoulos, S
Subjects: Hadron-Hadron scattering, QCD, Nuclear & Particles Physics, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This article presents a new set of proton parton distribution functions, ATLASepWZVjet20, produced in an analysis at next-to-next-to-leading order in QCD. The new data sets considered are the measurements of W+ and W− boson and Z boson production in association with jets in pp collisions at s = 8 TeV performed by the ATLAS experiment at the LHC with integrated luminosities of 20.2 fb−1 and 19.9 fb−1, respectively. The analysis also considers the ATLAS measurements of differential W± and Z boson production at s = 7 TeV with an integrated luminosity of 4.6 fb−1 and deep-inelastic-scattering data from e±p collisions at the HERA accelerator. An improved determination of the sea-quark densities at high Bjorken x is shown, while confirming a strange-quark density similar in size to the up- and down-sea-quark densities in the range x ≲ 0.02 found by previous ATLAS analyses. [Figure not available: see fulltext.]
Published: 2021

36. Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √s = 13 TeV

Author: Aad, G, Abbott, B, Abbott, DC, Abud, AA, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, CA, Adamczyk, L, Adamek, L, Adelman, J, Adersberger, M, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Verzini, MJA, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, EA, Estevez, MA, Alviggi, MG, Coutinho, YA, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Dos Santos, SPA, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JAA, Aparo, MA, Bella, LA, Barrio, NA, Ferraz, VA, and Pereira, RA
Subjects: Gaseous detectors, Muon spectrometers, Resistive-plate chambers, Trigger detectors, Nuclear & Particles Physics, Physical Sciences, Engineering
Abstract: The ATLAS experiment at the Large Hadron Collider (LHC) employs a trigger system consisting of a first-level hardware trigger (L1) and a software-based high-level trigger. The L1 muon trigger system selects muon candidates, assigns them to the correct LHC bunch crossing and classifies them into one of six transverse-momentum threshold classes. The L1 muon trigger system uses resistive-plate chambers (RPCs) to generate the muon-induced trigger signals in the central (barrel) region of the ATLAS detector. The ATLAS RPCs are arranged in six concentric layers and operate in a toroidal magnetic field with a bending power of 1.5 to 5.5 Tm. The RPC detector consists of about 3700 gas volumes with a total surface area of more than 4000 m2. This paper reports on the performance of the RPC detector and L1 muon barrel trigger using 60.8 fb-1 of proton-proton collision data recorded by the ATLAS experiment in 2018 at a centre-of-mass energy of 13 TeV. Detector and trigger performance are studied using Z boson decays into a muon pair. Measurements of the RPC detector response, efficiency, and time resolution are reported. Measurements of the L1 muon barrel trigger efficiencies and rates are presented, along with measurements of the properties of the selected sample of muon candidates. Measurements of the RPC currents, counting rates and mean avalanche charge are performed using zero-bias collisions. Finally, RPC detector response and efficiency are studied at different high voltage and front-end discriminator threshold settings in order to extrapolate detector response to the higher luminosity expected for the High Luminosity LHC.
Published: 2021

37. A search for the decays of stopped long-lived particles at √s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Abusleme Hoffman, AC, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arena, E, and Arguin, JF
Subjects: Hadron-Hadron scattering, Nuclear & Particles Physics, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: A search for long-lived particles, which have come to rest within the ATLAS detector, is presented. The subsequent decays of these particles can produce high-momentum jets, resulting in large out-of-time energy deposits in the ATLAS calorimeters. These de- cays are detected using data collected during periods in the LHC bunch structure when collisions are absent. The analysed dataset is composed of events from proton-proton collisions produced by the Large Hadron Collider at a centre-of-mass energy of s = 13 TeV and recorded by the ATLAS experiment during 2017 and 2018. The dataset used for this search corresponds to a total live time of 579 hours. The results of this search are used to derive lower limits on the mass of gluino R-hadrons, assuming a branching fraction B(g~→qq¯χ10) = 100%, with masses of up to 1.4 TeV excluded for gluino lifetimes of 10−5 to 103 s. [Figure not available: see fulltext.]
Published: 2021

38. Search for supersymmetry in events with four or more charged leptons in 139 fb −1 of √s = 13 TeV pp collisions with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Hadron-Hadron scattering, Supersymmetry, Beyond Standard Model, Nuclear & Particles Physics, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: A search for supersymmetry in events with four or more charged leptons (electrons, muons and τ-leptons) is presented. The analysis uses a data sample corresponding to 139 fb−1 of proton-proton collisions delivered by the Large Hadron Collider at s = 13 TeV and recorded by the ATLAS detector. Four-lepton signal regions with up to two hadronically decaying τ-leptons are designed to target several supersymmetric models, while a general five-lepton signal region targets any new physics phenomena leading to a final state with five charged leptons. Data yields are consistent with Standard Model expectations and results are used to set upper limits on contributions from processes beyond the Standard Model. Exclusion limits are set at the 95% confidence level in simplified models of general gauge-mediated supersymmetry, excluding higgsino masses up to 540 GeV. In R-parity-violating simplified models with decays of the lightest supersymmetric particle to charged leptons, lower limits of 1.6 TeV, 1.2 TeV, and 2.5 TeV are placed on wino, slepton and gluino masses, respectively. [Figure not available: see fulltext.]
Published: 2021

39. Muon reconstruction and identification efficiency in ATLAS using the full Run 2 pp collision data set at s=13 TeV

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: This article documents the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139 fb - 1 of pp collision data at s=13 TeV collected between 2015 and 2018 during Run 2 of the LHC. The increased instantaneous luminosity delivered by the LHC over this period required a reoptimisation of the criteria for the identification of prompt muons. Improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution. The availability of large samples of Z→ μμ and J/ ψ→ μμ decays, and the minimisation of systematic uncertainties, allows the efficiencies of criteria for muon identification, primary vertex association, and isolation to be measured with an accuracy at the per-mille level in the bulk of the phase space, and up to the percent level in complex kinematic configurations. Excellent performance is achieved over a range of transverse momenta from 3 GeV to several hundred GeV, and across the full muon detector acceptance of | η| < 2.7.
Published: 2021

40. Muon reconstruction and identification efficiency in ATLAS using the full Run 2 pp collision data set at s=13 TeV

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Akesson, TPA, Akilli, E, Akimov, AV, Khoury, K Al, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, and Arcangeletti, C
Subjects: Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: AbstractThis article documents the muon reconstruction and identification efficiency obtained by the ATLAS experiment for 139 $$\hbox {fb}^{-1}$$ fb - 1 of pp collision data at $$\sqrt{s}=13$$ s = 13 TeV collected between 2015 and 2018 during Run 2 of the LHC. The increased instantaneous luminosity delivered by the LHC over this period required a reoptimisation of the criteria for the identification of prompt muons. Improved and newly developed algorithms were deployed to preserve high muon identification efficiency with a low misidentification rate and good momentum resolution. The availability of large samples of $$Z\rightarrow \mu \mu $$ Z → μ μ and $$J/\psi \rightarrow \mu \mu $$ J / ψ → μ μ decays, and the minimisation of systematic uncertainties, allows the efficiencies of criteria for muon identification, primary vertex association, and isolation to be measured with an accuracy at the per-mille level in the bulk of the phase space, and up to the percent level in complex kinematic configurations. Excellent performance is achieved over a range of transverse momenta from 3 GeV to several hundred GeV, and across the full muon detector acceptance of $$|\eta |
Published: 2021

41. The ATLAS fast TracKer system

Author: Aad, G, Abbott, B, Abbott, DC, Abud, AA, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, CA, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Albicocco, P, Verzini, MJA, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Alison, J, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, EA, Estevez, MA, Alviggi, MG, Coutinho, YA, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Dos Santos, SPA, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Anderson, JT, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JAA, Aparo, MA, Bella, LA, Aranzabal, N, Ferraz, VA, and Pereira, RA
Subjects: Nuclear & Particles Physics, Physical Sciences, Engineering
Abstract: The ATLAS Fast TracKer (FTK) was designed to provide full tracking for the ATLAS high-level trigger by using pattern recognition based on Associative Memory (AM) chips and fitting in high-speed field programmable gate arrays. The tracks found by the FTK are based on inputs from all modules of the pixel and silicon microstrip trackers. The as-built FTK system and components are described, as is the online software used to control them while running in the ATLAS data acquisition system. Also described is the simulation of the FTK hardware and the optimization of the AM pattern banks. An optimization for long-lived particles with large impact parameter values is included. A test of the FTK system with the data playback facility that allowed the FTK to be commissioned during the shutdown between Run 2 and Run 3 of the LHC is reported. The resulting tracks from part of the FTK system covering a limited η-ϕ region of the detector are compared with the output from the FTK simulation. It is shown that FTK performance is in good agreement with the simulation.
Published: 2021

42. Search for squarks and gluinos in final states with one isolated lepton, jets, and missing transverse momentum at √s=13 with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The results of a search for gluino and squark pair production with the pairs decaying via the lightest charginos into a final state consisting of two W bosons, the lightest neutralinos (χ~10), and quarks, are presented: the signal is characterised by the presence of a single charged lepton (e± or μ±) from a W boson decay, jets, and missing transverse momentum. The analysis is performed using 139 fb- 1 of proton–proton collision data taken at a centre-of-mass energy s=13 delivered by the Large Hadron Collider and recorded by the ATLAS experiment. No statistically significant excess of events above the Standard Model expectation is found. Limits are set on the direct production of squarks and gluinos in simplified models. Masses of gluino (squark) up to 2.2 (1.4) are excluded at 95% confidence level for a light χ~10.
Published: 2021

43. Measurements of differential cross-sections in four-lepton events in 13 TeV proton-proton collisions with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Hadron-Hadron scattering, Lepton production, proton-proton scattering, Beyond Standard Model, Branching fraction, hep-ex, Nuclear & Particles Physics, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Measurements of four-lepton differential and integrated fiducial cross-sections in events with two same-flavour, opposite-charge electron or muon pairs are presented. The data correspond to 139 fb−1 of s = 13 TeV proton-proton collisions, collected by the ATLAS detector during Run 2 of the Large Hadron Collider (2015–2018). The final state has contributions from a number of interesting Standard Model processes that dominate in different four-lepton invariant mass regions, including single Z boson production, Higgs boson production and on-shell ZZ production, with a complex mix of interference terms, and possible contributions from physics beyond the Standard Model. The differential cross-sections include the four-lepton invariant mass inclusively, in slices of other kinematic variables, and in different lepton flavour categories. Also measured are dilepton invariant masses, transverse momenta, and angular correlation variables, in four regions of four-lepton invariant mass, each dominated by different processes. The measurements are corrected for detector effects and are compared with state-of-the-art Standard Model calculations, which are found to be consistent with the data. The Z → 4ℓ branching fraction is extracted, giving a value of (4.41 ± 0.30) × 10−6. Constraints on effective field theory parameters and a model based on a spontaneously broken B − L gauge symmetry are also evaluated. Further reinterpretations can be performed with the provided information. [Figure not available: see fulltext.]
Published: 2021

44. Measurements of Higgs bosons decaying to bottom quarks from vector boson fusion production with the ATLAS experiment at s=13TeV

Author: Aad, G, Abbott, B, Abbott, DC, Abud, A Abed, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, C Adam, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, E Alunno, Estevez, M Alvarez, Alviggi, MG, Coutinho, Y Amaral, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, Aranzabal, N, Ferraz, V Araujo, Pereira, R Araujo, Arcangeletti, C, Arce, ATH, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Astronomical sciences, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: The paper presents a measurement of the Standard Model Higgs Boson decaying to b-quark pairs in the vector boson fusion (VBF) production mode. A sample corresponding to 126 fb - 1 of s=13TeV proton–proton collision data, collected with the ATLAS experiment at the Large Hadron Collider, is analyzed utilizing an adversarial neural network for event classification. The signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, is measured to be 0.95-0.36+0.38 , corresponding to an observed (expected) significance of 2.6 (2.8) standard deviations from the background only hypothesis. The results are additionally combined with an analysis of Higgs bosons decaying to b-quarks, produced via VBF in association with a photon.
Published: 2021

45. Search for charged Higgs bosons decaying into a top quark and a bottom quark at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron scattering, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A search for charged Higgs bosons decaying into a top quark and a bottom quark is presented. The data analysed correspond to 139 fb−1 of proton-proton collisions at s = 13 TeV, recorded with the ATLAS detector at the LHC. The production of a heavy charged Higgs boson in association with a top quark and a bottom quark, pp → tbH+ → tbtb, is explored in the H+ mass range from 200 to 2000 GeV using final states with jets and one electron or muon. Events are categorised according to the multiplicity of jets and b-tagged jets, and multivariate analysis techniques are used to discriminate between signal and background events. No significant excess above the background-only hypothesis is observed and exclusion limits are derived for the production cross-section times branching ratio of a charged Higgs boson as a function of its mass; they range from 3.6 pb at 200 GeV to 0.036 pb at 2000 GeV at 95% confidence level. The results are interpreted in the hMSSM and Mh125 scenarios. [Figure not available: see fulltext.]
Published: 2021

46. Measurements of W+W−+ ≥ 1 jet production cross-sections in pp collisions at s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Abusleme Hoffman, AC, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arena, E, and Arguin, J-F
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Mathematical Physics, Mathematical Sciences, Physical Sciences, Hadron-Hadron scattering, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: Fiducial and differential cross-section measurements of W+W− production in association with at least one hadronic jet are presented. These measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton-proton collision data collected at s = 13 TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139 fb−1. Events are selected with exactly one oppositely charged electron-muon pair and at least one hadronic jet with a transverse momentum of pT> 30 GeV and a pseudorapidity of |η| < 4.5. After subtracting the background contributions and correcting for detector effects, the jet-inclusive W+W−+ ≥ 1 jet fiducial cross-section and W+W−+ jets differential cross-sections with respect to several kinematic variables are measured. These measurements include leptonic quantities, such as the lepton transverse momenta and the transverse mass of the W+W− system, as well as jet-related observables such as the leading jet transverse momentum and the jet multiplicity. Limits on anomalous triple-gauge-boson couplings are obtained in a phase space where interference between the Standard Model amplitude and the anomalous amplitude is enhanced. [Figure not available: see fulltext.]
Published: 2021

47. Search for doubly and singly charged Higgs bosons decaying into vector bosons in multi-lepton final states with the ATLAS detector using proton-proton collisions at s = 13 TeV

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arguin, J-F, and Argyropoulos, S
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Hadron-Hadron scattering, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Mathematical physics, Nuclear and plasma physics, Particle and high energy physics
Abstract: A search for charged Higgs bosons decaying into W±W± or W±Z bosons is performed, involving experimental signatures with two leptons of the same charge, or three or four leptons with a variety of charge combinations, missing transverse momentum and jets. A data sample of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider between 2015 and 2018 is used. The data correspond to a total integrated luminosity of 139 fb−1. The search is guided by a type-II seesaw model that extends the scalar sector of the Standard Model with a scalar triplet, leading to a phenomenology that includes doubly and singly charged Higgs bosons. Two scenarios are explored, corresponding to the pair production of doubly charged H±± bosons, or the associated production of a doubly charged H±± boson and a singly charged H± boson. No significant deviations from the Standard Model predictions are observed. H±± bosons are excluded at 95% confidence level up to 350 GeV and 230 GeV for the pair and associated production modes, respectively. [Figure not available: see fulltext.]
Published: 2021

48. Measurements of W + W −+ ≥ 1 jet production cross-sections in pp collisions at √s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Abusleme Hoffman, AC, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Arcangeletti, C, Arce, ATH, Arena, E, and Arguin, JF
Subjects: Hadron-Hadron scattering, hep-ex, Nuclear & Particles Physics, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Fiducial and differential cross-section measurements of W+W− production in association with at least one hadronic jet are presented. These measurements are sensitive to the properties of electroweak-boson self-interactions and provide a test of perturbative quantum chromodynamics and the electroweak theory. The analysis is performed using proton-proton collision data collected at s = 13 TeV with the ATLAS experiment, corresponding to an integrated luminosity of 139 fb−1. Events are selected with exactly one oppositely charged electron-muon pair and at least one hadronic jet with a transverse momentum of pT> 30 GeV and a pseudorapidity of |η| < 4.5. After subtracting the background contributions and correcting for detector effects, the jet-inclusive W+W−+ ≥ 1 jet fiducial cross-section and W+W−+ jets differential cross-sections with respect to several kinematic variables are measured. These measurements include leptonic quantities, such as the lepton transverse momenta and the transverse mass of the W+W− system, as well as jet-related observables such as the leading jet transverse momentum and the jet multiplicity. Limits on anomalous triple-gauge-boson couplings are obtained in a phase space where interference between the Standard Model amplitude and the anomalous amplitude is enhanced. [Figure not available: see fulltext.]
Published: 2021

49. Measurements of Higgs bosons decaying to bottom quarks from vector boson fusion production with the ATLAS experiment at √s=13TeV

Author: Aad, G, Abbott, B, Abbott, DC, Abud, AA, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Bourdarios, CA, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Verzini, MJA, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Camelia, EA, Estevez, MA, Alviggi, MG, Coutinho, YA, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Santos, SPAD, Amoroso, S, Amrouche, CS, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Pozo, JAA, Aparo, MA, Bella, LA, Aranzabal, N, Ferraz, VA, Pereira, RA, Arcangeletti, C, Arce, ATH, and Arguin, JF
Subjects: hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The paper presents a measurement of the Standard Model Higgs Boson decaying to b-quark pairs in the vector boson fusion (VBF) production mode. A sample corresponding to 126 fb - 1 of s=13TeV proton–proton collision data, collected with the ATLAS experiment at the Large Hadron Collider, is analyzed utilizing an adversarial neural network for event classification. The signal strength, defined as the ratio of the measured signal yield to that predicted by the Standard Model for VBF Higgs production, is measured to be 0.95-0.36+0.38 , corresponding to an observed (expected) significance of 2.6 (2.8) standard deviations from the background only hypothesis. The results are additionally combined with an analysis of Higgs bosons decaying to b-quarks, produced via VBF in association with a photon.
Published: 2021

50. Search for charged Higgs bosons decaying into a top quark and a bottom quark at √s = 13 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abbott, DC, Abed Abud, A, Abeling, K, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Achkar, B, Adam, L, Adam Bourdarios, C, Adamczyk, L, Adamek, L, Adelman, J, Adiguzel, A, Adorni, S, Adye, T, Affolder, AA, Afik, Y, Agapopoulou, C, Agaras, MN, Aggarwal, A, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmad, A, Ahmadov, F, Ahmed, WS, Ai, X, Aielli, G, Akatsuka, S, Akbiyik, M, Åkesson, TPA, Akilli, E, Akimov, AV, Al Khoury, K, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, A, Alfonsi, F, Alhroob, M, Ali, B, Ali, S, Aliev, M, Alimonti, G, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Alunno Camelia, E, Alvarez Estevez, M, Alviggi, MG, Amaral Coutinho, Y, Ambler, A, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, An, F, Anastopoulos, C, Andari, N, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aparo, MA, Aperio Bella, L, Aranzabal, N, Araujo Ferraz, V, Araujo Pereira, R, and Arcangeletti, C
Subjects: Hadron-Hadron scattering, Nuclear & Particles Physics, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: A search for charged Higgs bosons decaying into a top quark and a bottom quark is presented. The data analysed correspond to 139 fb−1 of proton-proton collisions at s = 13 TeV, recorded with the ATLAS detector at the LHC. The production of a heavy charged Higgs boson in association with a top quark and a bottom quark, pp → tbH+ → tbtb, is explored in the H+ mass range from 200 to 2000 GeV using final states with jets and one electron or muon. Events are categorised according to the multiplicity of jets and b-tagged jets, and multivariate analysis techniques are used to discriminate between signal and background events. No significant excess above the background-only hypothesis is observed and exclusion limits are derived for the production cross-section times branching ratio of a charged Higgs boson as a function of its mass; they range from 3.6 pb at 200 GeV to 0.036 pb at 2000 GeV at 95% confidence level. The results are interpreted in the hMSSM and Mh125 scenarios. [Figure not available: see fulltext.]
Published: 2021

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