954 results on '"Åkesson, A."'
Search Results
2. Search for scalar leptoquarks in pp collisions at s = 13 TeV with the ATLAS experiment
- Author
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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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