Author: "Åkesson, A." / Topic: atlas - Searchworks@Jio Institute Digital Library Search Results

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954 results on '"Åkesson, A."'

1. Performance and calibration of quark/gluon-jet taggers using 140 fb−1 of pp collisions at TeV with the ATLAS detector* *We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; ANID, Chile; CAS, MOST and NSFC, China; Minciencias, Colombia; MEYS CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRI, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MEiN, Poland; FCT, Portugal; MNE/IFA, Romania; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DSI/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taipei; TENMAK, Türkiye; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and mem

Author: Aad, G, Abbott, B, Abeling, K, Abicht, NJ, Abidi, SH, Aboulhorma, A, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Bourdarios, C Adam, Adamczyk, L, Addepalli, SV, Addison, MJ, Adelman, J, Adiguzel, A, Adye, T, Affolder, AA, Afik, Y, Agaras, MN, Agarwala, J, Aggarwal, A, Agheorghiesei, C, Ahmad, A, Ahmadov, F, Ahmed, WS, Ahuja, S, Ai, X, Aielli, G, Aikot, A, Tamlihat, M Ait, Aitbenchikh, B, Aizenberg, I, Akbiyik, M, Åkesson, TPA, Akimov, AV, Akiyama, D, Akolkar, NN, Al Khoury, K, Alberghi, GL, Albert, J, Albicocco, P, Albouy, GL, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alfonsi, F, Algren, M, Alhroob, M, Ali, B, Ali, HMJ, Ali, S, Alibocus, SW, Aliev, M, Alimonti, G, Alkakhi, W, Allaire, C, Allbrooke, BMM, Allen, JF, Flores, CA Allendes, Allport, PP, Aloisio, A, Alonso, F, Alpigiani, C, Estevez, M Alvarez, Fernandez, A Alvarez, Cardoso, M Alves, Alviggi, MG, Aly, M, Coutinho, Y Amaral, Ambler, A, Amelung, C, Amerl, M, Ames, CG, Amidei, D, Dos Santos, SP Amor, Amos, KR, Ananiev, V, Anastopoulos, C, Andeen, T, Anders, JK, Andrean, SY, Andreazza, A, Angelidakis, S, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antipov, E, Antonelli, M, Anulli, F, Aoki, M, Aoki, T, Pozo, JA Aparisi, Aparo, MA, Bella, L Aperio, and Appelt, C
Subjects: Particle and High Energy Physics, Physical Sciences, ATLAS, JET, QUARK, GLUON, TAGGING, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Atomic, molecular and optical physics, Particle and high energy physics
Abstract: The identification of jets originating from quarks and gluons, often referred to as quark/gluon tagging, plays an important role in various analyses performed at the Large Hadron Collider, as Standard Model measurements and searches for new particles decaying to quarks often rely on suppressing a large gluon-induced background. This paper describes the measurement of the efficiencies of quark/gluon taggers developed within the ATLAS Collaboration, using √s = 13 TeV proton–proton collision data with an integrated luminosity of 140 fb−1 collected by the ATLAS experiment. Two taggers with high performances in rejecting jets from gluon over jets from quarks are studied: one tagger is based on requirements on the number of inner-detector tracks associated with the jet, and the other combines several jet substructure observables using a boosted decision tree. A method is established to determine the quark/gluon fraction in data, by using quark/gluon-enriched subsamples defined by the jet pseudorapidity. Differences in tagging efficiency between data and simulation are provided for jets with transverse momentum between 500 GeV and 2 TeV and for multiple tagger working points.
Published: 2024

2. Search for scalar leptoquarks in pp collisions at s = 13 TeV with the ATLAS experiment

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agricola, J, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alstaty, M, Gonzalez, B Alvarez, Piqueras, D Álvarez, Alviggi, MG, Amadio, BT, Amako, K, Coutinho, Y Amaral, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonelli, M, Antonov, A, Anulli, F, Aoki, M, Bella, L Aperio, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Armitage, LJ, Arnaez, O, Arnold, H, Arratia, M, and Arslan, O
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, leptoquark, ATLAS, LHC, hep-ex, Fluids & Plasmas, Physical sciences
Abstract: An inclusive search for a new-physics signature of lepton-jet resonances has been performed by the ATLAS experiment. Scalar leptoquarks, pair-produced in pp collisions at s √S13 TeV at the large hadron collider, have been considered. An integrated luminosity of 3.2 fb−1, corresponding to the full 2015 dataset was used. First (second) generation leptoquarks were sought in events with two electrons (muons) and two or more jets. The observed event yield in each channel is consistent with Standard Model background expectations. The observed (expected) lower limits on the leptoquark mass at 95% confidence level are 1100 and 1050 GeV (1160 and 1040 GeV) for first and second generation leptoquarks, respectively, assuming a branching ratio into a charged lepton and a quark of 100%. Upper limits on the aforementioned branching ratio are also given as a function of leptoquark mass. Compared with the results of earlier ATLAS searches, the sensitivity is increased for leptoquark masses above 860 GeV, and the observed exclusion limits confirm and extend the published results.
Published: 2016

3. Search for scalar leptoquarks in pp collisions at √S = 13TeV with the ATLAS experiment

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, Abou Zeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agricola, J, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alstaty, M, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, Amako, K, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonelli, M, Antonov, A, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, JF, Argyropoulos, S, Arik, M, Armbruster, AJ, Armitage, LJ, Arnaez, O, Arnold, H, Arratia, M, and Arslan, O
Subjects: leptoquark, ATLAS, LHC, hep-ex, Fluids & Plasmas, Physical Sciences
Abstract: An inclusive search for a new-physics signature of lepton-jet resonances has been performed by the ATLAS experiment. Scalar leptoquarks, pair-produced in pp collisions at s √S13 TeV at the large hadron collider, have been considered. An integrated luminosity of 3.2 fb−1, corresponding to the full 2015 dataset was used. First (second) generation leptoquarks were sought in events with two electrons (muons) and two or more jets. The observed event yield in each channel is consistent with Standard Model background expectations. The observed (expected) lower limits on the leptoquark mass at 95% confidence level are 1100 and 1050 GeV (1160 and 1040 GeV) for first and second generation leptoquarks, respectively, assuming a branching ratio into a charged lepton and a quark of 100%. Upper limits on the aforementioned branching ratio are also given as a function of leptoquark mass. Compared with the results of earlier ATLAS searches, the sensitivity is increased for leptoquark masses above 860 GeV, and the observed exclusion limits confirm and extend the published results.
Published: 2016

4. Search for a CP-odd Higgs boson decaying to Zh in pp collisions at √s=8 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimoto, G, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, JF, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnold, H, Arratia, M, and Arslan, O
Subjects: BSM Higgs boson, ATLAS, hep-ex, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for a heavy, CP-odd Higgs boson, A, decaying into a Z boson and a 125 GeV Higgs boson, h, with the ATLAS detector at the LHC is presented. The search uses proton–proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb−1. Decays of CP-even h bosons to ττ or bb pairs with the Z boson decaying to electron or muon pairs are considered, as well as h→bb decays with the Z boson decaying to neutrinos. No evidence for the production of an A boson in these channels is found and the 95% confidence level upper limits derived for σ(gg→A)×BR(A→Zh)×BR(h→ff¯) are 0.098–0.013 pb for f=τ and 0.57–0.014 pb for f=b in a range of mA=220–1000 GeV. The results are combined and interpreted in the context of two-Higgs-doublet models.
Published: 2015

5. Search for a CP-odd Higgs boson decaying to Zh in pp collisions at s=8 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimoto, G, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnold, H, and Arratia, M
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, BSM Higgs boson, ATLAS, 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 a heavy, CP-odd Higgs boson, A, decaying into a Z boson and a 125 GeV Higgs boson, h, with the ATLAS detector at the LHC is presented. The search uses proton–proton collision data at a centre-of-mass energy of 8 TeV corresponding to an integrated luminosity of 20.3 fb−1. Decays of CP-even h bosons to ττ or bb pairs with the Z boson decaying to electron or muon pairs are considered, as well as h→bb decays with the Z boson decaying to neutrinos. No evidence for the production of an A boson in these channels is found and the 95% confidence level upper limits derived for σ(gg→A)×BR(A→Zh)×BR(h→ff¯) are 0.098–0.013 pb for f=τ and 0.57–0.014 pb for f=b in a range of mA=220–1000 GeV. The results are combined and interpreted in the context of two-Higgs-doublet models.
Published: 2015

6. Measurement of the top-quark mass in the fully hadronic decay channel from ATLAS data at s=7TeV

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimoto, G, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Almond, J, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Araque, JP, Arce, ATH, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, and Arnal, V
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS Collaboration, ATLAS, Fully hadronic, LHC, Proton–proton collisions, Top quark, Top-quark mass, 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 mass of the top quark is measured in a data set corresponding to 4.6 [Formula: see text] of proton-proton collisions with centre-of-mass energy [Formula: see text] TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top-antitop quark pairs with at least six jets in the final state are selected. The substantial background from multijet production is modelled with data-driven methods that utilise the number of identified [Formula: see text]-quark jets and the transverse momentum of the sixth leading jet, which have minimal correlation. The top-quark mass is obtained from template fits to the ratio of three-jet to dijet mass. The three-jet mass is calculated from the three jets produced in a top-quark decay. Using these three jets the dijet mass is obtained from the two jets produced in the [Formula: see text] boson decay. The top-quark mass obtained from this fit is thus less sensitive to the uncertainty in the energy measurement of the jets. A binned likelihood fit yields a top-quark mass of [Formula: see text].
Published: 2015

7. Search for s-channel single top-quark production in proton-proton collisions at √s=8 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimoto, G, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, JF, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, and Arnal, V
Subjects: ATLAS, Top quark, Electroweak production, s-Channel, hep-ex, Nuclear & Particles Physics, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This Letter presents a search at the LHC for s-channel single top-quark production in proton-proton collisions at a centre-of-mass energy of 8 TeV. The analyzed data set was recorded by the ATLAS detector and corresponds to an integrated luminosity of 20.3 fb-1. Selected events contain one charged lepton, large missing transverse momentum and exactly two b-tagged jets. A multivariate event classifier based on boosted decision trees is developed to discriminate s-channel single top-quark events from the main background contributions. The signal extraction is based on a binned maximum-likelihood fit of the output classifier distribution. The analysis leads to an upper limit on the s-channel single top-quark production cross-section of 14.6 pb at the 95% confidence level. The fit gives a cross-section of σs = 5.0 ± 4.3 pb, consistent with the Standard Model expectation.
Published: 2015

8. Measurement of the top-quark mass in the fully hadronic decay channel from ATLAS data at [Formula: see text].

Author: ATLAS Collaboration, Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimoto, G, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Almond, J, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Araque, JP, Arce, ATH, Arguin, J-F, Argyropoulos, S, and Arik, M
Subjects: ATLAS Collaboration, ATLAS, Fully hadronic, LHC, Proton–proton collisions, Top quark, Top-quark mass, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The mass of the top quark is measured in a data set corresponding to 4.6 [Formula: see text] of proton-proton collisions with centre-of-mass energy [Formula: see text] TeV collected by the ATLAS detector at the LHC. Events consistent with hadronic decays of top-antitop quark pairs with at least six jets in the final state are selected. The substantial background from multijet production is modelled with data-driven methods that utilise the number of identified [Formula: see text]-quark jets and the transverse momentum of the sixth leading jet, which have minimal correlation. The top-quark mass is obtained from template fits to the ratio of three-jet to dijet mass. The three-jet mass is calculated from the three jets produced in a top-quark decay. Using these three jets the dijet mass is obtained from the two jets produced in the [Formula: see text] boson decay. The top-quark mass obtained from this fit is thus less sensitive to the uncertainty in the energy measurement of the jets. A binned likelihood fit yields a top-quark mass of [Formula: see text].
Published: 2015

9. Search for s-channel single top-quark production in proton–proton collisions at s=8 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Agatonovic-Jovin, T, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimoto, G, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Coutinho, Y Amaral, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angelidakis, S, Angelozzi, I, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Arnaez, O
Subjects: Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, ATLAS, Top quark, Electroweak production, s-Channel, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Mathematical sciences, Physical sciences
Abstract: This Letter presents a search at the LHC for s-channel single top-quark production in proton-proton collisions at a centre-of-mass energy of 8 TeV. The analyzed data set was recorded by the ATLAS detector and corresponds to an integrated luminosity of 20.3 fb-1. Selected events contain one charged lepton, large missing transverse momentum and exactly two b-tagged jets. A multivariate event classifier based on boosted decision trees is developed to discriminate s-channel single top-quark events from the main background contributions. The signal extraction is based on a binned maximum-likelihood fit of the output classifier distribution. The analysis leads to an upper limit on the s-channel single top-quark production cross-section of 14.6 pb at the 95% confidence level. The fit gives a cross-section of σs = 5.0 ± 4.3 pb, consistent with the Standard Model expectation.
Published: 2015

10. Charged-particle multiplicities in pp interactions at √ s = 900 GeV measured with the ATLAS detector at the LHC

Author: Aad, G, Abat, E, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Ackers, M, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adorisio, C, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahmed, H, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, PF, Åkesson, TPA, Akimoto, G, Akimov, AV, Aktas, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Aleppo, M, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, J, Alviggi, MG, Amako, K, Amaral, P, Ambrosini, G, Ambrosio, G, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonelli, S, Antos, J, Antunovic, B, Anulli, F, Aoun, S, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Argyropoulos, T, Arik, E, Arik, M, and Armbruster, AJ
Subjects: Charged-particle, Multiplicities, GeV, ATLAS, LHC, Minimum bias, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and chargedparticle multiplicity are measured for events with at least one charged particle in the kinematic range |η| < 2.5 and pT > 500 MeV. The measurements are compared to Monte Carlo models of proton-proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity at η = 0 is measured to be 1.333 ± 0.003(stat.) ± 0.040(syst.), which is 5-15% higher than the Monte Carlo models predict.
Published: 2010

11. Charged-particle multiplicities in pp interactions at s=900 GeV measured with the ATLAS detector at the LHC

Author: Collaboration, ATLAS, Aad, G, Abat, E, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Ackers, M, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adorisio, C, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahmed, H, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, PF, Åkesson, TPA, Akimoto, G, Akimov, AV, Aktas, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Aleppo, M, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, J, Alviggi, MG, Amako, K, Amaral, P, Ambrosini, G, Ambrosio, G, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonelli, S, Antos, J, Antunovic, B, Anulli, F, Aoun, S, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Argyropoulos, T, Arik, E, and Arik, M
Subjects: Charged-particle, Multiplicities, GeV, ATLAS, LHC, Minimum bias, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: The first measurements from proton-proton collisions recorded with the ATLAS detector at the LHC are presented. Data were collected in December 2009 using a minimum-bias trigger during collisions at a centre-of-mass energy of 900 GeV. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity, and the relationship between mean transverse momentum and chargedparticle multiplicity are measured for events with at least one charged particle in the kinematic range |η| < 2.5 and pT > 500 MeV. The measurements are compared to Monte Carlo models of proton-proton collisions and to results from other experiments at the same centre-of-mass energy. The charged-particle multiplicity per event and unit of pseudorapidity at η = 0 is measured to be 1.333 ± 0.003(stat.) ± 0.040(syst.), which is 5-15% higher than the Monte Carlo models predict.
Published: 2010

12. The ATLAS Experiment at the CERN Large Hadron Collider

Author: Collaboration, The ATLAS, Aad, G, Abat, E, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, BA, Abolins, M, Abramowicz, H, Acerbi, E, Acharya, BS, Achenbach, R, Ackers, M, Adams, DL, Adamyan, F, Addy, TN, Aderholz, M, Adorisio, C, Adragna, P, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahmed, H, Aielli, G, Åkesson, PF, Åkesson, TPA, Akimov, AV, Alam, SM, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Aleppo, M, Alessandria, F, Alexa, C, Alexander, G, Alexopoulos, T, Alimonti, G, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Aloisio, A, Alonso, J, Alves, R, Alviggi, MG, Amako, K, Amaral, P, Amaral, SP, Ambrosini, G, Ambrosio, G, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Anderson, B, Anderson, KJ, Anderssen, EC, Andreazza, A, Andrei, V, Andricek, L, Andrieux, M-L, Anduaga, XS, Anghinolfi, F, Antonaki, A, Antonelli, M, Antonelli, S, Apsimon, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arguin, J-F, Arik, E, Arik, M, Arms, KE, Armstrong, SR, Arnaud, M, Arnault, C, Artamonov, A, Asai, S, Ask, S, Åsman, B, Asner, D, Asquith, L, Assamagan, K, Astbury, A, Athar, B, Atkinson, T, Aubert, B, Auerbach, B, Auge, E, Augsten, K, Aulchenko, VM, Austin, N, Avolio, G, and Avramidou, R
Subjects: ATLAS, LHC, CERN, Accelerator, Proton-proton collisions, Heavy-ion collisions, Minimum-bias events, Bunch-crossings, Pile-up, Superconducting magnets, Solenoidal field, Toroidal field, Magnetic field measurements, Hall probes, Inner detector, Charged-particle tracking, Vertex measurement, Pixel detectors, Silicon micro-strip detectors, Transition radiation, Time-over-threshold, Radiation-hard electronics, Fluorinert cooling, Carbon-fibre reinforced plastics, Optical fibres, Calorimetry, Sampling calorimeters, Liquid argon, Scintillator tiles, Electromagnetic and hadronic interactions, Forward calorimetry, Accordion geometry, Lateral segmentation, Longitudinal segmentation, Muon spectrometer, Precision-tracking chambers, Trigger chambers, Drift tubes, Thin-gap chambers, Resistive-plate chambers, Optical alignment systems, Forward detectors, Cerenkov light, Roman Pots, Zero-degree calorimetry, Trigger and data acquisition, High-level trigger, Event filter, Detector control system, Bandwidth, Processor farm, Electrons, Muons, Leptons, Photons, Jets, Taus, Missing transverse energy, b-tagging, Particle identification, Tracking algorithms, Vertexing algorithms, Impact parameter measurements, Physical Sciences, Engineering, Nuclear & Particles Physics
Published: 2008

13. Search for single b⁎-quark production with the ATLAS detector at √s=7 TeV

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Ochoa, MI, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, and Argyropoulos, S
Subjects: ATLAS, b*, Single top-quark, Excited quark, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The results of a search for an excited bottom-quark b⁎ in pp collisions at s=7 TeV, using 4.7 fb−1 of data collected by the ATLAS detector at the LHC are presented. In the model studied, a single b⁎-quark is produced through a chromomagnetic interaction and subsequently decays to a W boson and a top quark. The search is performed in the dilepton and lepton + jets final states, which are combined to set limits on b⁎-quark couplings for a range of b⁎-quark masses. For a benchmark with unit size chromomagnetic and Standard Model-like electroweak b⁎ couplings, b⁎ quarks with masses less than 870 GeV are excluded at the 95% credibility level.
Published: 2013

14. Search for single b⁎-quark production with the ATLAS detector at s=7 TeV

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Ochoa, MI, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allison, LJ, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amoroso, S, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angelidakis, S, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, and Arguin, J-F
Subjects: ATLAS, b*, Single top-quark, Excited quark, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: The results of a search for an excited bottom-quark b⁎ in pp collisions at s=7 TeV, using 4.7 fb−1 of data collected by the ATLAS detector at the LHC are presented. In the model studied, a single b⁎-quark is produced through a chromomagnetic interaction and subsequently decays to a W boson and a top quark. The search is performed in the dilepton and lepton + jets final states, which are combined to set limits on b⁎-quark couplings for a range of b⁎-quark masses. For a benchmark with unit size chromomagnetic and Standard Model-like electroweak b⁎ couplings, b⁎ quarks with masses less than 870 GeV are excluded at the 95% credibility level.
Published: 2013

15. Searches for heavy long-lived sleptons and R-hadrons with the ATLAS detector in pp collisions at √s=7 TeV

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amor Dos Santos, SP, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, and Arik, M
Subjects: Long-lived, GMSB, Slepton, R-hadron, ATLAS, LHC, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for long-lived particles is performed using a data sample of 4.7 fb−1 from proton–proton collisions at a centre-of-mass energy s=7 TeV collected by the ATLAS detector at the LHC. No excess is observed above the estimated background and lower limits, at 95% confidence level, are set on the mass of the long-lived particles in different scenarios, based on their possible interactions in the inner detector, the calorimeters and the muon spectrometer. Long-lived staus in gauge-mediated SUSY-breaking models are excluded up to a mass of 300 GeV for tanβ=5–20. Directly produced long-lived sleptons are excluded up to a mass of 278 GeV. R-hadrons, composites of gluino (stop, sbottom) and light quarks, are excluded up to a mass of 985 GeV (683 GeV, 612 GeV) when using a generic interaction model. Additionally two sets of limits on R-hadrons are obtained that are less sensitive to the interaction model for R-hadrons. One set of limits is obtained using only the inner detector and calorimeter observables, and a second set of limits is obtained based on the inner detector alone.
Published: 2013

16. Searches for heavy long-lived sleptons and R-hadrons with the ATLAS detector in pp collisions at s=7 TeV

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Altheimer, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Dos Santos, SP Amor, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, and Arik, E
Subjects: Long-lived, GMSB, Slepton, R-hadron, ATLAS, LHC, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for long-lived particles is performed using a data sample of 4.7 fb−1 from proton–proton collisions at a centre-of-mass energy s=7 TeV collected by the ATLAS detector at the LHC. No excess is observed above the estimated background and lower limits, at 95% confidence level, are set on the mass of the long-lived particles in different scenarios, based on their possible interactions in the inner detector, the calorimeters and the muon spectrometer. Long-lived staus in gauge-mediated SUSY-breaking models are excluded up to a mass of 300 GeV for tanβ=5–20. Directly produced long-lived sleptons are excluded up to a mass of 278 GeV. R-hadrons, composites of gluino (stop, sbottom) and light quarks, are excluded up to a mass of 985 GeV (683 GeV, 612 GeV) when using a generic interaction model. Additionally two sets of limits on R-hadrons are obtained that are less sensitive to the interaction model for R-hadrons. One set of limits is obtained using only the inner detector and calorimeter observables, and a second set of limits is obtained based on the inner detector alone.
Published: 2013

17. Measurement of the jet radius and transverse momentum dependence of inclusive jet suppression in lead–lead collisions at √sNN=2.76 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, and Artoni, G
Subjects: LHC, ATLAS, Heavy ion, Jets, hep-ex, nucl-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead–lead collisions at sNN=2.76 TeV corresponding to an integrated luminosity of approximately 7 μb−1, ATLAS has measured jets with a calorimeter system over the pseudorapidity interval |η|
Published: 2013

18. Measurement of the jet radius and transverse momentum dependence of inclusive jet suppression in lead–lead collisions at sNN=2.76 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, and Artamonov, A
Subjects: LHC, ATLAS, Heavy ion, Jets, hep-ex, nucl-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead–lead collisions at sNN=2.76 TeV corresponding to an integrated luminosity of approximately 7 μb−1, ATLAS has measured jets with a calorimeter system over the pseudorapidity interval |η|
Published: 2013

19. Search for the Standard Model Higgs boson produced in association with a vector boson and decaying to a b-quark pair with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, and Artamonov, A
Subjects: Standard Model Higgs boson, ATLAS, LHC, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This Letter presents the results of a direct search with the ATLAS detector at the LHC for a Standard Model Higgs boson of mass 110⩽mH⩽130 GeV produced in association with a W or Z boson and decaying to bb¯. Three decay channels are considered: ZH→ℓ+ℓ−bb¯ WH→ℓνbb¯ and ZH→νν¯bb¯ where ℓ corresponds to an electron or a muon. No evidence for Higgs boson production is observed in a dataset of 7 TeV pp collisions corresponding to 4.7 fb−1 of integrated luminosity collected by ATLAS in 2011. Exclusion limits on Higgs boson production, at the 95% confidence level, of 2.5 to 5.5 times the Standard Model cross section are obtained in the mass range 110–130 GeV. The expected exclusion limits range between 2.5 and 4.9 for the same mass interval.
Published: 2012

20. Search for the Higgs boson in the H→WW→ℓνjj decay channel at √s=7 TeV with the ATLAS detector

Author: Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, and Arnaez, O
Subjects: ATLAS, LHC, Higgs, WW, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for the Standard Model Higgs boson has been performed in the H→WW→ℓνjj channel using 4.7 fb−1 of pp collision data recorded at a centre-of-mass energy of s=7 TeV with the ATLAS detector at the Large Hadron Collider. Higgs boson candidates produced in association with zero, one or two jets are included in the analysis to maximize the acceptance for both gluon fusion and weak boson fusion Higgs boson production processes. No significant excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 300 GeV
Published: 2012

21. Search for the Standard Model Higgs boson produced in association with a vector boson and decaying to a b-quark pair with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, and Arnault, C
Subjects: Standard Model Higgs boson, ATLAS, LHC, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: This Letter presents the results of a direct search with the ATLAS detector at the LHC for a Standard Model Higgs boson of mass 110⩽mH⩽130 GeV produced in association with a W or Z boson and decaying to bb¯. Three decay channels are considered: ZH→ℓ+ℓ−bb¯ WH→ℓνbb¯ and ZH→νν¯bb¯ where ℓ corresponds to an electron or a muon. No evidence for Higgs boson production is observed in a dataset of 7 TeV pp collisions corresponding to 4.7 fb−1 of integrated luminosity collected by ATLAS in 2011. Exclusion limits on Higgs boson production, at the 95% confidence level, of 2.5 to 5.5 times the Standard Model cross section are obtained in the mass range 110–130 GeV. The expected exclusion limits range between 2.5 and 4.9 for the same mass interval.
Published: 2012

22. Search for the Higgs boson in the H→WW→ℓνjj decay channel at s=7 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abajyan, T, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Aben, R, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, F, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoki, M, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, and Armbruster, AJ
Subjects: ATLAS, LHC, Higgs, WW, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for the Standard Model Higgs boson has been performed in the H→WW→ℓνjj channel using 4.7 fb−1 of pp collision data recorded at a centre-of-mass energy of s=7 TeV with the ATLAS detector at the Large Hadron Collider. Higgs boson candidates produced in association with zero, one or two jets are included in the analysis to maximize the acceptance for both gluon fusion and weak boson fusion Higgs boson production processes. No significant excess of events is observed over the expected background and limits on the Higgs boson production cross section are derived for a Higgs boson mass in the range 300 GeV
Published: 2012

23. Search for a Standard Model Higgs boson in the mass range 200–600 GeV in the H→ZZ→ℓ+ℓ−qq¯ decay channel with the ATLAS Detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, and Artoni, G
Subjects: Standard Model Higgs boson, ATLAS, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for a heavy Standard Model Higgs boson decaying via H→ZZ→ℓ+ℓ−qq¯, where ℓ=e or μ, is presented. The search uses a data set of pp collisions at s=7 TeV, corresponding to an integrated luminosity of 4.7 fb−1 collected in 2011 by the ATLAS detector at the CERN LHC. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section of a Higgs boson with a mass in the range between 200 and 600 GeV are derived. A Standard Model Higgs boson with a mass in the range 300 GeV⩽mH⩽322 GeV or 353 GeV⩽mH⩽410 GeV is excluded at 95% CL. The corresponding expected exclusion range is 351 GeV⩽mH⩽404 GeV at 95% CL.
Published: 2012

24. Search for a standard model Higgs boson in the H→ZZ→ℓ+ℓ−νν¯ decay channel using 4.7 fb−1 of √s=7 TeV data with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, Artoni, G, and Arutinov, D
Subjects: Standard Model Higgs Boson, ATLAS, hep-ex, Atomic, Molecular, Nuclear, Particle And Plasma Physics, Nuclear & Particles Physics, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for a Standard Model Higgs boson decaying via H→ZZ→ℓ+ℓ−νν¯ where ℓ represents electrons or muons, is presented. It is based on proton-proton collision data at s=7 TeV, collected by the ATLAS experiment at the LHC during 2011 and corresponding to an integrated luminosity of 4.7 fb−1. The data agree with the expected Standard Model backgrounds. Upper limits on the Higgs boson production cross section are derived for Higgs boson masses between 200 GeV and 600 GeV and the production of a Standard Model Higgs boson with a mass in the range 319–558 GeV is excluded at the 95% confidence level.
Published: 2012

25. Search for a standard model Higgs boson in the H→ZZ→ℓ+ℓ−νν¯ decay channel using 4.7 fb−1 of s=7 TeV data with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, and Artoni, G
Subjects: Standard Model Higgs Boson, ATLAS, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for a Standard Model Higgs boson decaying via H→ZZ→ℓ+ℓ−νν¯ where ℓ represents electrons or muons, is presented. It is based on proton-proton collision data at s=7 TeV, collected by the ATLAS experiment at the LHC during 2011 and corresponding to an integrated luminosity of 4.7 fb−1. The data agree with the expected Standard Model backgrounds. Upper limits on the Higgs boson production cross section are derived for Higgs boson masses between 200 GeV and 600 GeV and the production of a Standard Model Higgs boson with a mass in the range 319–558 GeV is excluded at the 95% confidence level.
Published: 2012

26. Search for a Standard Model Higgs boson in the mass range 200–600 GeV in the H→ZZ→ℓ+ℓ−qq¯ decay channel with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, and Artamonov, A
Subjects: Standard Model Higgs boson, ATLAS, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for a heavy Standard Model Higgs boson decaying via H→ZZ→ℓ+ℓ−qq¯, where ℓ=e or μ, is presented. The search uses a data set of pp collisions at s=7 TeV, corresponding to an integrated luminosity of 4.7 fb−1 collected in 2011 by the ATLAS detector at the CERN LHC. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section of a Higgs boson with a mass in the range between 200 and 600 GeV are derived. A Standard Model Higgs boson with a mass in the range 300 GeV⩽mH⩽322 GeV or 353 GeV⩽mH⩽410 GeV is excluded at 95% CL. The corresponding expected exclusion range is 351 GeV⩽mH⩽404 GeV at 95% CL.
Published: 2012

27. Search for the Standard Model Higgs boson in the H→WW(⋆)→ℓνℓν decay mode with 4.7 fb−1 of ATLAS data at √s=7 TeV

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, and Artoni, G
Subjects: ATLAS, LHC, Higgs, WW, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for the Standard Model Higgs boson in the H→WW(⋆)→ℓνℓν (ℓ=e,μ) decay mode is presented. The search is performed using proton–proton collision data corresponding to an integrated luminosity of 4.7 fb−1 at a centre-of-mass energy of 7 TeV collected during 2011 with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed. An upper bound is placed on the Higgs boson production cross section as a function of its mass. A Standard Model Higgs boson with mass in the range between 133 GeV and 261 GeV is excluded at 95% confidence level, while the expected exclusion range is from 127 GeV to 233 GeV.
Published: 2012

28. Evidence for the associated production of a W boson and a top quark in ATLAS at √s=7TeV

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, Artoni, G, and Arutinov, D
Subjects: ATLAS, Top quark, W plus t, Single top-quark, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at s=7TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt=16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb|=1.03−0.19+0.16 is derived assuming that the Wt production through |Vts| and |Vtd| is small.
Published: 2012

29. Search for the Standard Model Higgs boson in the H→WW(⋆)→ℓνℓν decay mode with 4.7 fb−1 of ATLAS data at s=7 TeV

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Agustoni, M, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Anger, P, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, and Artamonov, A
Subjects: ATLAS, LHC, Higgs, WW, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for the Standard Model Higgs boson in the H→WW(⋆)→ℓνℓν (ℓ=e,μ) decay mode is presented. The search is performed using proton–proton collision data corresponding to an integrated luminosity of 4.7 fb−1 at a centre-of-mass energy of 7 TeV collected during 2011 with the ATLAS detector at the Large Hadron Collider. No significant excess of events over the expected background is observed. An upper bound is placed on the Higgs boson production cross section as a function of its mass. A Standard Model Higgs boson with mass in the range between 133 GeV and 261 GeV is excluded at 95% confidence level, while the expected exclusion range is from 127 GeV to 233 GeV.
Published: 2012

30. Evidence for the associated production of a W boson and a top quark in ATLAS at s=7TeV

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, and Artoni, G
Subjects: ATLAS, Top quark, W plus t, Single top-quark, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: This Letter presents evidence for the associated production of a W boson and a top quark using 2.05 fb−1 of pp collision data at s=7TeV accumulated with the ATLAS detector at the LHC. The analysis is based on the selection of the dileptonic final states with events featuring two isolated leptons, electron or muon, with significant transverse missing momentum and at least one jet. An approach based on boosted decision trees has been developed to improve the discrimination of single top-quark Wt events from background. A template fit to the final classifier distributions is performed to determine the cross-section. The result is incompatible with the background-only hypothesis at the 3.3σ level, the expected sensitivity assuming the Standard Model production rate being 3.4σ. The corresponding cross-section is determined and found to be σWt=16.8±2.9 (stat)±4.9 (syst) pb, in good agreement with the Standard Model expectation. From this result the CKM matrix element |Vtb|=1.03−0.19+0.16 is derived assuming that the Wt production through |Vts| and |Vtd| is small.
Published: 2012

31. Search for the decay Bs 0→μ+μ- with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, JF, Arik, E, and Arik, M
Subjects: B meson, Rare decays, FCNC, ATLAS, LHC, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A blind analysis searching for the decay Bs 0→μ+μ- has been performed using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. With an integrated luminosity of 2.4 fb-1 no excess of events over the background expectation is found and an upper limit is set on the branching fraction BR(Bs 0→μ+μ-)
Published: 2012

32. Search for the decay Bs0→μ+μ− with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amelung, C, Ammosov, VV, Amorim, A, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnault, C, Artamonov, A, and Artoni, G
Subjects: B meson, Rare decays, FCNC, ATLAS, LHC, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A blind analysis searching for the decay Bs 0→μ+μ- has been performed using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. With an integrated luminosity of 2.4 fb-1 no excess of events over the background expectation is found and an upper limit is set on the branching fraction BR(Bs 0→μ+μ-)
Published: 2012

33. Search for the Standard Model Higgs boson in the decay channel H→ZZ(*)→4ℓ with 4.8 fb-1 of pp collision data at √s=7 TeV with ATLAS

Author: Aad, G, Abbott, B, Abdallah, J, Abdel Khalek, S, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, and Arai, Y
Subjects: LHC, ATLAS, Higgs, Leptons, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This Letter presents a search for the Standard Model Higgs boson in the decay channel H→ZZ(*)→ℓ+ℓ-ℓ'+ℓ'-, where ℓ, ℓ'=e or μ, using proton-proton collisions at √s=7 TeV recorded with the ATLAS detector and corresponding to an integrated luminosity of 4.8 fb-1. The four-lepton invariant mass distribution is compared with Standard Model background expectations to derive upper limits on the cross section of a Standard Model Higgs boson with a mass between 110 GeV and 600 GeV. The mass ranges 134-156 GeV, 182-233 GeV, 256-265 GeV and 268-415 GeV are excluded at the 95% confidence level. The largest upward deviations from the background-only hypothesis are observed for Higgs boson masses of 125 GeV, 244 GeV and 500 GeV with local significances of 2.1, 2.2 and 2.1 standard deviations, respectively. Once the look-elsewhere effect is considered, none of these excesses are significant. © 2012 CERN.
Published: 2012

34. Search for the Standard Model Higgs boson in the decay channel H→ZZ(⁎)→4ℓ with 4.8 fb−1 of pp collision data at s=7 TeV with ATLAS

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Khalek, S Abdel, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, AbouZeid, OS, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allbrooke, BMM, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anisenkov, A, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Arfaoui, S, Arguin, J-F, Arik, E, and Arik, M
Subjects: LHC, ATLAS, Higgs, Leptons, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: This Letter presents a search for the Standard Model Higgs boson in the decay channel H→ZZ(*)→ℓ+ℓ-ℓ'+ℓ'-, where ℓ, ℓ'=e or μ, using proton-proton collisions at √s=7 TeV recorded with the ATLAS detector and corresponding to an integrated luminosity of 4.8 fb-1. The four-lepton invariant mass distribution is compared with Standard Model background expectations to derive upper limits on the cross section of a Standard Model Higgs boson with a mass between 110 GeV and 600 GeV. The mass ranges 134-156 GeV, 182-233 GeV, 256-265 GeV and 268-415 GeV are excluded at the 95% confidence level. The largest upward deviations from the background-only hypothesis are observed for Higgs boson masses of 125 GeV, 244 GeV and 500 GeV with local significances of 2.1, 2.2 and 2.1 standard deviations, respectively. Once the look-elsewhere effect is considered, none of these excesses are significant. © 2012 CERN.
Published: 2012

35. Search for strong gravity signatures in same-sign dimuon final states using the ATLAS detector at the LHC

Author: Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alvarez Gonzalez, B, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Artamonov, A, Artoni, G, and Arutinov, D
Subjects: LHC, ATLAS, Microscopic black holes, Extra dimensions, Same-sign dimuons, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for microscopic black holes has been performed in a same-sign dimuon final state using 1.3 fb -1 of proton-proton collision data collected with the ATLAS detector at a centre of mass energy of 7 TeV at the CERN Large Hadron Collider. The data are found to be consistent with the expectation from the Standard Model and the results are used to derive exclusion contours in the context of a low scale gravity model. © 2012 CERN.
Published: 2012

36. Search for strong gravity signatures in same-sign dimuon final states using the ATLAS detector at the LHC

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Gonzalez, B Alvarez, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Artamonov, A, and Artoni, G
Subjects: LHC, ATLAS, Microscopic black holes, Extra dimensions, Same-sign dimuons, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for microscopic black holes has been performed in a same-sign dimuon final state using 1.3 fb -1 of proton-proton collision data collected with the ATLAS detector at a centre of mass energy of 7 TeV at the CERN Large Hadron Collider. The data are found to be consistent with the expectation from the Standard Model and the results are used to derive exclusion contours in the context of a low scale gravity model. © 2012 CERN.
Published: 2012

37. Measurement of the pseudorapidity and transverse momentum dependence of the elliptic flow of charged particles in lead–lead collisions at sNN=2.76 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andari, N, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, Arutinov, D, Asai, S, and Asfandiyarov, R
Subjects: LHC, ATLAS, Heavy ions, Elliptic flow, hep-ex, nucl-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: This Letter describes the measurement of elliptic flow of charged particles in lead-lead collisions at sNN=2.76 TeV using the ATLAS detector at the Large Hadron Collider (LHC). The results are based on an integrated luminosity of approximately 7 μb-1. Elliptic flow is measured over a wide region in pseudorapidity, |η|
Published: 2012

38. Measurement of the pseudorapidity and transverse momentum dependence of the elliptic flow of charged particles in lead-lead collisions at sNN=2.76 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andari, N, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, Arutinov, D, Asai, S, Asfandiyarov, R, and Ask, S
Subjects: LHC, ATLAS, Heavy ions, Elliptic flow, hep-ex, nucl-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This Letter describes the measurement of elliptic flow of charged particles in lead-lead collisions at sNN=2.76 TeV using the ATLAS detector at the Large Hadron Collider (LHC). The results are based on an integrated luminosity of approximately 7 μb-1. Elliptic flow is measured over a wide region in pseudorapidity, |η|
Published: 2012

39. Search for a heavy Standard Model Higgs boson in the channel H→ZZ→ℓ+ℓ-qq̄ using the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angelidakis, S, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, and Artoni, G
Subjects: Standard Model Higgs boson, ATLAS, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for a heavy Standard Model Higgs boson decaying via H→ZZ→ℓ+ℓ-qq̄, where ℓ=e, μ, is presented. The search is performed using a data set of pp collisions at √s=7 TeV, corresponding to an integrated luminosity of 1.04 fb-1 collected in 2011 by the ATLAS detector at the CERN LHC collider. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section (relative to that expected from the Standard Model) of a Higgs boson with a mass in the range between 200 and 600 GeV are derived. Within this mass range, there is at present insufficient sensitivity to exclude a Standard Model Higgs boson. For a Higgs boson with a mass of 360 GeV, where the sensitivity is maximal, the observed and expected cross section upper limits are factors of 1.7 and 2.7, respectively, larger than the Standard Model prediction. © 2011 CERN.
Published: 2012

40. Search for a heavy Standard Model Higgs boson in the channel H→ZZ→ℓ+ℓ−qq¯ using the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angelidakis, S, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, and Artamonov, A
Subjects: Standard Model Higgs boson, ATLAS, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for a heavy Standard Model Higgs boson decaying via H→ZZ→ℓ+ℓ-qq̄, where ℓ=e, μ, is presented. The search is performed using a data set of pp collisions at √s=7 TeV, corresponding to an integrated luminosity of 1.04 fb-1 collected in 2011 by the ATLAS detector at the CERN LHC collider. No significant excess of events above the estimated background is found. Upper limits at 95% confidence level on the production cross section (relative to that expected from the Standard Model) of a Higgs boson with a mass in the range between 200 and 600 GeV are derived. Within this mass range, there is at present insufficient sensitivity to exclude a Standard Model Higgs boson. For a Higgs boson with a mass of 360 GeV, where the sensitivity is maximal, the observed and expected cross section upper limits are factors of 1.7 and 2.7, respectively, larger than the Standard Model prediction. © 2011 CERN.
Published: 2012

41. Measurement of the inclusive isolated prompt photon cross-section in pp collisions at √s=7 TeV using 35 pb-1 of ATLAS data

Author: Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, and Arutinov, D
Subjects: Photon, ATLAS, LHC, Standard Model, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy √s=7 TeV is presented. The measurement covers the pseudorapidity ranges |η|
Published: 2011

42. Measurement of the inclusive isolated prompt photon cross-section in pp collisions at s=7 TeV using 35 pb−1 of ATLAS data

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, and Artoni, G
Subjects: Photon, ATLAS, LHC, Standard Model, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy √s=7 TeV is presented. The measurement covers the pseudorapidity ranges |η|
Published: 2011

43. Search for the Standard Model Higgs boson in the decay channel H→ZZ(*)→4ℓ with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, and Arutinov, D
Subjects: LHC, ATLAS, Higgs, Leptons, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: A search for the Standard Model Higgs boson in the decay channel H→ZZ(*)→ℓ+ℓ-ℓ'+ℓ'-, where ℓ=e, μ, is presented. Proton-proton collision data at s=7TeV recorded with the ATLAS detector and corresponding to an average integrated luminosity of 2.1fb-1 are compared to the Standard Model expectations. Upper limits on the production cross section of a Standard Model Higgs boson with a mass between 110 and 600GeV are derived. The observed (expected) 95% confidence level upper limit on the production cross section for a Higgs boson with a mass of 194 GeV, the region with the best expected sensitivity for this search, is 0.99 (1.01) times the Standard Model prediction. The Standard Model Higgs boson is excluded at 95% confidence level in the mass ranges 191-197, 199-200 and 214-224 GeV. © 2011 CERN.
Published: 2011

44. Search for the Standard Model Higgs boson in the decay channel H→ZZ(⁎)→4ℓ with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albert, J, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, G, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, and Artoni, G
Subjects: LHC, ATLAS, Higgs, Leptons, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for the Standard Model Higgs boson in the decay channel H→ZZ(*)→ℓ+ℓ-ℓ'+ℓ'-, where ℓ=e, μ, is presented. Proton-proton collision data at s=7TeV recorded with the ATLAS detector and corresponding to an average integrated luminosity of 2.1fb-1 are compared to the Standard Model expectations. Upper limits on the production cross section of a Standard Model Higgs boson with a mass between 110 and 600GeV are derived. The observed (expected) 95% confidence level upper limit on the production cross section for a Higgs boson with a mass of 194 GeV, the region with the best expected sensitivity for this search, is 0.99 (1.01) times the Standard Model prediction. The Standard Model Higgs boson is excluded at 95% confidence level in the mass ranges 191-197, 199-200 and 214-224 GeV. © 2011 CERN.
Published: 2011

45. Search for heavy long-lived charged particles with the ATLAS detector in pp collisions at s=7 TeV

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andari, N, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, Arutinov, D, Asai, S, and Asfandiyarov, R
Subjects: SUSY, ATLAS, Long-lived particles, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for long-lived charged particles reaching the muon spectrometer is performed using a data sample of 37 pb-1 from pp collisions at √s=7 TeV collected by the ATLAS detector at the LHC in 2010. No excess is observed above the estimated background. Stable τ̃ sleptons are excluded at 95% CL up to a mass of 136 GeV, in GMSB models with N5=3, mmessenger=250 TeV, sign(μ)=1 and tanβ=5. Electroweak production of sleptons is excluded up to a mass of 110 GeV. Gluino R-hadrons in a generic interaction model are excluded up to masses of 530 GeV to 544 GeV depending on the fraction of R-hadrons produced as g̃-balls. © 2011 CERN.
Published: 2011

46. Search for squarks and gluinos using final states with jets and missing transverse momentum with the ATLAS detector in s=7 TeV proton–proton collisions

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Aleppo, M, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonelli, S, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, Arutinov, D, Asai, S, Asfandiyarov, R, and Ask, S
Subjects: Supersymmetry, Squark, Gluino, Search, LHC, ATLAS, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: A search for squarks and gluinos in final states containing jets, missing transverse momentum and no electrons or muons is presented. The data were recorded by the ATLAS experiment in √s=7 TeV proton-proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in 35 pb-1 of analysed data. Gluino masses below 500 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino. The exclusion increases to 870 GeV for equal mass squarks and gluinos. In MSUGRA/CMSSM models with tanβ=3, A0=0 and μ>0, squarks and gluinos of equal mass are excluded below 775 GeV. These are the most stringent limits to date. © 2011 CERN.
Published: 2011

47. Search for supersymmetry in pp collisions at s=7 TeV in final states with missing transverse momentum and b-jets

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Akiyama, A, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonelli, S, Antonov, A, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, Arutinov, D, Asai, S, and Asfandiyarov, R
Subjects: Supersymmetry, ATLAS, LHC, Sbottom, Stop, Gluino, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: Results are presented of a search for supersymmetric particles in events with large missing transverse momentum and at least one heavy flavour jet candidate in √s=7 TeV proton-proton collisions. In a data sample corresponding to an integrated luminosity of 35 pb-1 recorded by the ATLAS experiment at the Large Hadron Collider, no significant excess is observed with respect to the prediction for Standard Model processes. For R-parity conserving models in which sbottoms (stops) are the only squarks to appear in the gluino decay cascade, gluino masses below 590 GeV (520 GeV) are excluded at the 95% C.L. The results are also interpreted in an MSUGRA/CMSSM supersymmetry breaking scenario with tanβ=40 and in an SO(10) model framework. © 2011 CERN.
Published: 2011

48. Measurement of the production cross section for W-bosons in association with jets in pp collisions at √s=7 TeV with the ATLAS detector

Author: Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Ackers, M, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Aleppo, M, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, J, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonelli, S, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arms, KE, Armstrong, SR, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, and Arutinov, D
Subjects: W-boson, Jets, ATLAS, LHC, Proton-proton, TeV, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This Letter reports on a first measurement of the inclusive W+jets cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC, with the ATLAS detector. Cross sections, in both the electron and muon decay modes of the W-boson, are presented as a function of jet multiplicity and of the transverse momentum of the leading and next-to-leading jets in the event. Measurements are also presented of the ratio of cross sections σ(W+≥n)/σ(W+≥n-1) for inclusive jet multiplicities n=1-4. The results, based on an integrated luminosity of 1.3 pb-1, have been corrected for all known detector effects and are quoted in a limited and well-defined range of jet and lepton kinematics. The measured cross sections are compared to particle-level predictions based on perturbative QCD. Next-to-leading order calculations, studied here for n≤2, are found in good agreement with the data. Leading-order multiparton event generators, normalized to the NNLO total cross section, describe the data well for all measured jet multiplicities. © 2011 CERN Elsevier B.V.
Published: 2011

49. Measurement of the production cross section for W-bosons in association with jets in pp collisions at s=7 TeV with the ATLAS detector

Author: Collaboration, ATLAS, Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Ackers, M, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Aleppo, M, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, J, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, M-L, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonelli, S, Antos, J, Anulli, F, Aoun, S, Bella, L Aperio, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, J-F, Arik, E, Arik, M, Armbruster, AJ, Arms, KE, Armstrong, SR, Arnaez, O, Arnault, C, Artamonov, A, and Artoni, G
Subjects: W-boson, Jets, ATLAS, LHC, Proton-proton, TeV, hep-ex, Mathematical Physics, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics
Abstract: This Letter reports on a first measurement of the inclusive W+jets cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC, with the ATLAS detector. Cross sections, in both the electron and muon decay modes of the W-boson, are presented as a function of jet multiplicity and of the transverse momentum of the leading and next-to-leading jets in the event. Measurements are also presented of the ratio of cross sections σ(W+≥n)/σ(W+≥n-1) for inclusive jet multiplicities n=1-4. The results, based on an integrated luminosity of 1.3 pb-1, have been corrected for all known detector effects and are quoted in a limited and well-defined range of jet and lepton kinematics. The measured cross sections are compared to particle-level predictions based on perturbative QCD. Next-to-leading order calculations, studied here for n≤2, are found in good agreement with the data. Leading-order multiparton event generators, normalized to the NNLO total cross section, describe the data well for all measured jet multiplicities. © 2011 CERN Elsevier B.V.
Published: 2011

50. Measurement of the centrality dependence of J/Ψ yields and observation of Z production in lead-lead collisions with the ATLAS detector at the LHC

Author: Aad, G, Abbott, B, Abdallah, J, Abdelalim, AA, Abdesselam, A, Abdinov, O, Abi, B, Abolins, M, Abramowicz, H, Abreu, H, Acerbi, E, Acharya, BS, Ackers, M, Adams, DL, Addy, TN, Adelman, J, Aderholz, M, Adomeit, S, Adragna, P, Adye, T, Aefsky, S, Aguilar-Saavedra, JA, Aharrouche, M, Ahlen, SP, Ahles, F, Ahmad, A, Ahsan, M, Aielli, G, Akdogan, T, Åkesson, TPA, Akimoto, G, Akimov, AV, Alam, MS, Alam, MA, Albrand, S, Aleksa, M, Aleksandrov, IN, Aleppo, M, Alessandria, F, Alexa, C, Alexander, G, Alexandre, G, Alexopoulos, T, Alhroob, M, Aliev, M, Alimonti, G, Alison, J, Aliyev, M, Allport, PP, Allwood-Spiers, SE, Almond, J, Aloisio, A, Alon, R, Alonso, A, Alonso, J, Alviggi, MG, Amako, K, Amaral, P, Amelung, C, Ammosov, VV, Amorim, A, Amorós, G, Amram, N, Anastopoulos, C, Andeen, T, Anders, CF, Anderson, KJ, Andreazza, A, Andrei, V, Andrieux, ML, Anduaga, XS, Angerami, A, Anghinolfi, F, Anjos, N, Annovi, A, Antonaki, A, Antonelli, M, Antonelli, S, Antos, J, Anulli, F, Aoun, S, Aperio Bella, L, Apolle, R, Arabidze, G, Aracena, I, Arai, Y, Arce, ATH, Archambault, JP, Arfaoui, S, Arguin, JF, Arik, E, Arik, M, Armbruster, AJ, Arms, KE, Armstrong, SR, Arnaez, O, Arnault, C, Artamonov, A, Artoni, G, and Arutinov, D
Subjects: ATLAS, LHC, Heavy ions, J/psi, Z boson, Centrality dependence, hep-ex, nucl-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Astronomical and Space Sciences, Mathematical Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: Using the ATLAS detector, a centrality-dependent suppression has been observed in the yield of J/Ψ mesons produced in the collisions of lead ions at the Large Hadron Collider. In a sample of minimum-bias lead-lead collisions at a nucleon-nucleon centre of mass energy sNN=2.76 TeV, corresponding to an integrated luminosity of about 6.7 μb-1, J/Ψ mesons are reconstructed via their decays to μ+μ- pairs. The measured J/Ψ yield, normalized to the number of binary nucleon-nucleon collisions, is found to significantly decrease from peripheral to central collisions. The centrality dependence is found to be qualitatively similar to the trends observed at previous, lower energy experiments. The same sample is used to reconstruct Z bosons in the μ+μ- final state, and a total of 38 candidates are selected in the mass window of 66 to 116 GeV. The relative Z yields as a function of centrality are also presented, although no conclusion can be inferred about their scaling with the number of binary collisions, because of limited statistics. This analysis provides the first results on J/Ψ and Z production in lead-lead collisions at the LHC. © 2011 CERN.
Published: 2011

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