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52 results

1. Jet reconstruction and performance using particle flow with the ATLAS Detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akimov, AV, Alberghi, GL, Albert, J, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, M, Gonzalez, B Alvarez, Piqueras, D Álvarez, Alviggi, MG, Amadio, BT, Coutinho, Y Amaral, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amorim, A, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Bella, L Aperio, Arabidze, G, Arai, Y, Araque, JP, Ferraz, V Araujo, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Armitage, LJ, and Arnaez, O
Subjects: ATLAS Collaboration, Bioengineering, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper describes the implementation and performance of a particle flow algorithm applied to 20.2 fb[Formula: see text] of ATLAS data from 8 TeV proton-proton collisions in Run 1 of the LHC. The algorithm removes calorimeter energy deposits due to charged hadrons from consideration during jet reconstruction, instead using measurements of their momenta from the inner tracker. This improves the accuracy of the charged-hadron measurement, while retaining the calorimeter measurements of neutral-particle energies. The paper places emphasis on how this is achieved, while minimising double-counting of charged-hadron signals between the inner tracker and calorimeter. The performance of particle flow jets, formed from the ensemble of signals from the calorimeter and the inner tracker, is compared to that of jets reconstructed from calorimeter energy deposits alone, demonstrating improvements in resolution and pile-up stability.
Published: 2017

2. Development and validation of HERWIG 7 tunes from CMS underlying-event measurements.

Author: Sirunyan, AM, Tumasyan, A, Adam, W, Ambrogi, F, Bergauer, T, Dragicevic, M, Erö, J, Escalante Del Valle, A, Frühwirth, R, Jeitler, M, Krammer, N, Lechner, L, Liko, D, Madlener, T, Mikulec, I, Pitters, FM, Rad, N, Schieck, J, Schöfbeck, R, Spanring, M, Templ, S, Waltenberger, W, Wulz, C-E, Zarucki, M, Chekhovsky, V, Litomin, A, Makarenko, V, Suarez Gonzalez, J, Darwish, MR, De Wolf, EA, Croce, D Di, Janssen, X, Kello, T, Lelek, A, Pieters, M, Sfar, H Rejeb, Van Haevermaet, H, Van Mechelen, P, Van Putte, S, Van Remortel, N, Blekman, F, Bols, ES, Chhibra, SS, D'Hondt, J, De Clercq, J, Lontkovskyi, D, Lowette, S, Marchesini, I, Moortgat, S, Morton, A, Python, Q, Tavernier, S, Van Doninck, W, Van Mulders, P, Beghin, D, Bilin, B, Clerbaux, B, De Lentdecker, G, Delannoy, H, Dorney, B, Favart, L, Grebenyuk, A, Kalsi, AK, Makarenko, I, Moureaux, L, Pétré, L, Popov, A, Postiau, N, Starling, E, Thomas, L, Vander Velde, C, Vanlaer, P, Vannerom, D, Wezenbeek, L, Cornelis, T, Dobur, D, Gruchala, M, Khvastunov, I, Niedziela, M, Roskas, C, Skovpen, K, Tytgat, M, Verbeke, W, Vermassen, B, Vit, M, Bruno, G, Bury, F, Caputo, C, David, P, Delaere, C, Delcourt, M, Donertas, IS, Giammanco, A, Lemaitre, V, Mondal, K, Prisciandaro, J, Taliercio, A, Teklishyn, M, Vischia, P, and Wuyckens, S
Subjects: CMS Collaboration, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: This paper presents new sets of parameters ("tunes") for the underlying-event model of the HERWIG7 event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in HERWIG7 , and are obtained from a fit to minimum-bias data collected by the CMS experiment at s=0.9 , 7, and 13Te . The tunes are based on the NNPDF 3.1 next-to-next-to-leading-order parton distribution function (PDF) set for the parton shower, and either a leading-order or next-to-next-to-leading-order PDF set for the simulation of MPI and the beam remnants. Predictions utilizing the tunes are produced for event shape observables in electron-positron collisions, and for minimum-bias, inclusive jet, top quark pair, and Z and W boson events in proton-proton collisions, and are compared with data. Each of the new tunes describes the data at a reasonable level, and the tunes using a leading-order PDF for the simulation of MPI provide the best description of the data.
Published: 2021

3. Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration.

Author: Abi, B, Acciarri, R, Acero, MA, Adamov, G, Adams, D, Adinolfi, M, Ahmad, Z, Ahmed, J, Alion, T, Monsalve, S Alonso, Alt, C, Anderson, J, Andreopoulos, C, Andrews, MP, Andrianala, F, Andringa, S, Ankowski, A, Antonova, M, Antusch, S, Aranda-Fernandez, A, Ariga, A, Arnold, LO, Arroyave, MA, Asaadi, J, Aurisano, A, Aushev, V, Autiero, D, Azfar, F, Back, H, Back, JJ, Backhouse, C, Baesso, P, Bagby, L, Bajou, R, Balasubramanian, S, Baldi, P, Bambah, B, Barao, F, Barenboim, G, Barker, GJ, Barkhouse, W, Barnes, C, Barr, G, Monarca, J Barranco, Barros, N, Barrow, JL, Bashyal, A, Basque, V, Bay, F, Alba, JL Bazo, Beacom, JF, Bechetoille, E, Behera, B, Bellantoni, L, Bellettini, G, Bellini, V, Beltramello, O, Belver, D, Benekos, N, Neves, F Bento, Berger, J, Berkman, S, Bernardini, P, Berner, RM, Berns, H, Bertolucci, S, Betancourt, M, Bezawada, Y, Bhattacharjee, M, Bhuyan, B, Biagi, S, Bian, J, Biassoni, M, Biery, K, Bilki, B, Bishai, M, Bitadze, A, Blake, A, Siffert, B Blanco, Blaszczyk, FDM, Blazey, GC, Blucher, E, Boissevain, J, Bolognesi, S, Bolton, T, Bonesini, M, Bongrand, M, Bonini, F, Booth, A, Booth, C, Bordoni, S, Borkum, A, Boschi, T, Bostan, N, Bour, P, Boyd, SB, Boyden, D, Bracinik, J, Braga, D, and Brailsford, D
Subjects: hep-ex, hep-ph, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.
Published: 2021

4. Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration.

Author: Abi, B, Acciarri, R, Acero, MA, Adamov, G, Adams, D, Adinolfi, M, Ahmad, Z, Ahmed, J, Alion, T, Monsalve, S Alonso, Alt, C, Anderson, J, Andreopoulos, C, Andrews, MP, Andrianala, F, Andringa, S, Ankowski, A, Antonova, M, Antusch, S, Aranda-Fernandez, A, Ariga, A, Arnold, LO, Arroyave, MA, Asaadi, J, Aurisano, A, Aushev, V, Autiero, D, Azfar, F, Back, H, Back, JJ, Backhouse, C, Baesso, P, Bagby, L, Bajou, R, Balasubramanian, S, Baldi, P, Bambah, B, Barao, F, Barenboim, G, Barker, GJ, Barkhouse, W, Barnes, C, Barr, G, Monarca, J Barranco, Barros, N, Barrow, JL, Bashyal, A, Basque, V, Bay, F, Alba, JL Bazo, Beacom, JF, Bechetoille, E, Behera, B, Bellantoni, L, Bellettini, G, Bellini, V, Beltramello, O, Belver, D, Benekos, N, Neves, F Bento, Berger, J, Berkman, S, Bernardini, P, Berner, RM, Berns, H, Bertolucci, S, Betancourt, M, Bezawada, Y, Bhattacharjee, M, Bhuyan, B, Biagi, S, Bian, J, Biassoni, M, Biery, K, Bilki, B, Bishai, M, Bitadze, A, Blake, A, Siffert, B Blanco, Blaszczyk, FDM, Blazey, GC, Blucher, E, Boissevain, J, Bolognesi, S, Bolton, T, Bonesini, M, Bongrand, M, Bonini, F, Booth, A, Booth, C, Bordoni, S, Borkum, A, Boschi, T, Bostan, N, Bour, P, Boyd, SB, Boyden, D, Bracinik, J, Braga, D, and Brailsford, D
Subjects: hep-ex, hep-ph, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.
Published: 2021

5. A multi-dimensional search for new heavy resonances decaying to boosted W W , W Z , or Z Z boson pairs in the dijet final state at 13 Te.

Author: Sirunyan, AM, Tumasyan, A, Adam, W, Ambrogi, F, Bergauer, T, Brandstetter, J, Dragicevic, M, Erö, J, Del Valle, A Escalante, Flechl, M, Frühwirth, R, Jeitler, M, Krammer, N, Krätschmer, I, Liko, D, Madlener, T, Mikulec, I, Rad, N, Schieck, J, Schöfbeck, R, Spanring, M, Spitzbart, D, Waltenberger, W, Wulz, C-E, Zarucki, M, Drugakov, V, Mossolov, V, Gonzalez, J Suarez, Darwish, MR, De Wolf, EA, Di Croce, D, Janssen, X, Lauwers, J, Lelek, A, Pieters, M, Sfar, H Rejeb, Van Haevermaet, H, Van Mechelen, P, Van Putte, S, Van Remortel, N, Blekman, F, Bols, ES, Chhibra, SS, D'Hondt, J, De Clercq, J, Lontkovskyi, D, Lowette, S, Marchesini, I, Moortgat, S, Moreels, L, Python, Q, Skovpen, K, Tavernier, S, Van Doninck, W, Van Mulders, P, Van Parijs, I, Beghin, D, Bilin, B, Brun, H, Clerbaux, B, De Lentdecker, G, Delannoy, H, Dorney, B, Favart, L, Grebenyuk, A, Kalsi, AK, Luetic, J, Popov, A, Postiau, N, Starling, E, Thomas, L, Velde, C Vander, Vanlaer, P, Vannerom, D, Cornelis, T, Dobur, D, Khvastunov, I, Niedziela, M, Roskas, C, Trocino, D, Tytgat, M, Verbeke, W, Vermassen, B, Vit, M, Zaganidis, N, Bondu, O, Bruno, G, Caputo, C, David, P, Delaere, C, Delcourt, M, Giammanco, A, Lemaitre, V, Magitteri, A, Prisciandaro, J, Saggio, A, Marono, M Vidal, Vischia, P, Zobec, J, and Alves, FL
Subjects: CMS Collaboration, CMS, Diboson resonances, Physics, Substructure, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: A search in an all-jet final state for new massive resonances decaying to W W , W Z , or Z Z boson pairs using a novel analysis method is presented. The analysis is performed on data corresponding to an integrated luminosity of 77.3 fb-1 recorded with the CMS experiment at the LHC at a centre-of-mass energy of 13 Te . The search is focussed on potential narrow-width resonances with masses above 1.2 Te , where the decay products of each W or Z boson are expected to be collimated into a single, large-radius jet. The signal is extracted using a three-dimensional maximum likelihood fit of the two jet masses and the dijet invariant mass, yielding an improvement in sensitivity of up to 30% relative to previous search methods. No excess is observed above the estimated standard model background. In a heavy vector triplet model, spin-1 Z' and W' resonances with masses below 3.5 and 3.8 Te , respectively, are excluded at 95% confidence level. In a bulk graviton model, upper limits on cross sections are set between 27 and 0.2 fb for resonance masses between 1.2 and 5.2 Te , respectively. The limits presented in this paper are the best to date in the dijet final state.
Published: 2020

6. The Pandora multi-algorithm approach to automated pattern recognition of cosmic-ray muon and neutrino events in the MicroBooNE detector.

Author: Acciarri, R, Adams, C, An, R, Anthony, J, Asaadi, J, Auger, M, Bagby, L, Balasubramanian, S, Baller, B, Barnes, C, Barr, G, Bass, M, Bay, F, Bishai, M, Blake, A, Bolton, T, Camilleri, L, Caratelli, D, Carls, B, Castillo Fernandez, R, Cavanna, F, Chen, H, Church, E, Cianci, D, Cohen, E, Collin, GH, Conrad, JM, Convery, M, Crespo-Anadón, JI, Del Tutto, M, Devitt, D, Dytman, S, Eberly, B, Ereditato, A, Escudero Sanchez, L, Esquivel, J, Fadeeva, AA, Fleming, BT, Foreman, W, Furmanski, AP, Garcia-Gamez, D, Garvey, GT, Genty, V, Goeldi, D, Gollapinni, S, Graf, N, Gramellini, E, Greenlee, H, Grosso, R, Guenette, R, Hackenburg, A, Hamilton, P, Hen, O, Hewes, J, Hill, C, Ho, J, Horton-Smith, G, Hourlier, A, Huang, E-C, James, C, Jan de Vries, J, Jen, C-M, Jiang, L, Johnson, RA, Joshi, J, Jostlein, H, Kaleko, D, Karagiorgi, G, Ketchum, W, Kirby, B, Kirby, M, Kobilarcik, T, Kreslo, I, Laube, A, Li, Y, Lister, A, Littlejohn, BR, Lockwitz, S, Lorca, D, Louis, WC, Luethi, M, Lundberg, B, Luo, X, Marchionni, A, Mariani, C, Marshall, J, Martinez Caicedo, DA, Meddage, V, Miceli, T, Mills, GB, Moon, J, Mooney, M, Moore, CD, Mousseau, J, Murrells, R, Naples, D, Nienaber, P, Nowak, J, Palamara, O, and Paolone, V
Subjects: hep-ex, physics.data-an, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The development and operation of liquid-argon time-projection chambers for neutrino physics has created a need for new approaches to pattern recognition in order to fully exploit the imaging capabilities offered by this technology. Whereas the human brain can excel at identifying features in the recorded events, it is a significant challenge to develop an automated, algorithmic solution. The Pandora Software Development Kit provides functionality to aid the design and implementation of pattern-recognition algorithms. It promotes the use of a multi-algorithm approach to pattern recognition, in which individual algorithms each address a specific task in a particular topology. Many tens of algorithms then carefully build up a picture of the event and, together, provide a robust automated pattern-recognition solution. This paper describes details of the chain of over one hundred Pandora algorithms and tools used to reconstruct cosmic-ray muon and neutrino events in the MicroBooNE detector. Metrics that assess the current pattern-recognition performance are presented for simulated MicroBooNE events, using a selection of final-state event topologies.
Published: 2018

7. Analysis of cryogenic calorimeters with light and heat read-out for double beta decay searches.

Author: Azzolini, O, Barrera, MT, Beeman, JW, Bellini, F, Beretta, M, Biassoni, M, Bossio, E, Brofferio, C, Bucci, C, Canonica, L, Capelli, S, Cardani, L, Carniti, P, Casali, N, Cassina, L, Clemenza, M, Cremonesi, O, Cruciani, A, D'Addabbo, A, Dafinei, I, Domizio, S Di, Ferroni, F, Gironi, L, Giuliani, A, Gorla, P, Gotti, C, Keppel, G, Martinez, M, Morganti, S, Nagorny, S, Nastasi, M, Nisi, S, Nones, C, Orlandi, D, Pagnanini, L, Pallavicini, M, Palmieri, V, Pattavina, L, Pavan, M, Pessina, G, Pettinacci, V, Pirro, S, Pozzi, S, Previtali, E, Puiu, A, Rusconi, C, Schäffner, K, Tomei, C, Vignati, M, and Zolotarova, A
Subjects: Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The suppression of spurious events in the region of interest for neutrinoless double beta decay will play a major role in next generation experiments. The background of detectors based on the technology of cryogenic calorimeters is expected to be dominated by α particles, that could be disentangled from double beta decay signals by exploiting the difference in the emission of the scintillation light. CUPID-0, an array of enriched Zn 82 Se scintillating calorimeters, is the first large mass demonstrator of this technology. The detector started data-taking in 2017 at the Laboratori Nazionali del Gran Sasso with the aim of proving that dual read-out of light and heat allows for an efficient suppression of the α background. In this paper we describe the software tools we developed for the analysis of scintillating calorimeters and we demonstrate that this technology allows to reach an unprecedented background for cryogenic calorimeters.
Published: 2018

8. The Pandora multi-algorithm approach to automated pattern recognition of cosmic-ray muon and neutrino events in the MicroBooNE detector.

Author: Acciarri, R, Adams, C, An, R, Anthony, J, Asaadi, J, Auger, M, Bagby, L, Balasubramanian, S, Baller, B, Barnes, C, Barr, G, Bass, M, Bay, F, Bishai, M, Blake, A, Bolton, T, Camilleri, L, Caratelli, D, Carls, B, Castillo Fernandez, R, Cavanna, F, Chen, H, Church, E, Cianci, D, Cohen, E, Collin, GH, Conrad, JM, Convery, M, Crespo-Anadón, JI, Del Tutto, M, Devitt, A, Dytman, S, Eberly, B, Ereditato, A, Escudero Sanchez, L, Esquivel, J, Fadeeva, AA, Fleming, BT, Foreman, W, Furmanski, AP, Garcia-Gamez, D, Garvey, GT, Genty, V, Goeldi, D, Gollapinni, S, Graf, N, Gramellini, E, Greenlee, H, Grosso, R, Guenette, R, Hackenburg, A, Hamilton, P, Hen, O, Hewes, J, Hill, C, Ho, J, Horton-Smith, G, Hourlier, A, Huang, E-C, James, C, Jan de Vries, J, Jen, C-M, Jiang, L, Johnson, RA, Joshi, J, Jostlein, H, Kaleko, D, Karagiorgi, G, Ketchum, W, Kirby, B, Kirby, M, Kobilarcik, T, Kreslo, I, Laube, A, Li, Y, Lister, A, Littlejohn, BR, Lockwitz, S, Lorca, D, Louis, WC, Luethi, M, Lundberg, B, Luo, X, Marchionni, A, Mariani, C, Marshall, J, Martinez Caicedo, DA, Meddage, V, Miceli, T, Mills, GB, Moon, J, Mooney, M, Moore, CD, Mousseau, J, Murrells, R, Naples, D, Nienaber, P, Nowak, J, Palamara, O, and Paolone, V
Subjects: Networking and Information Technology R&D, Bioengineering, hep-ex, physics.data-an, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: The development and operation of liquid-argon time-projection chambers for neutrino physics has created a need for new approaches to pattern recognition in order to fully exploit the imaging capabilities offered by this technology. Whereas the human brain can excel at identifying features in the recorded events, it is a significant challenge to develop an automated, algorithmic solution. The Pandora Software Development Kit provides functionality to aid the design and implementation of pattern-recognition algorithms. It promotes the use of a multi-algorithm approach to pattern recognition, in which individual algorithms each address a specific task in a particular topology. Many tens of algorithms then carefully build up a picture of the event and, together, provide a robust automated pattern-recognition solution. This paper describes details of the chain of over one hundred Pandora algorithms and tools used to reconstruct cosmic-ray muon and neutrino events in the MicroBooNE detector. Metrics that assess the current pattern-recognition performance are presented for simulated MicroBooNE events, using a selection of final-state event topologies.
Published: 2018

9. Direct top-quark decay width measurement in the tt¯ lepton+jets channel at s=8TeV with the ATLAS experiment.

Author: Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Afik, Y, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Verzini, MJ Alconada, Alderweireldt, SC, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Gonzalez, B Alvarez, Piqueras, D Álvarez, Alviggi, MG, Amadio, BT, Coutinho, Y Amaral, Amelung, C, Amidei, D, Dos Santos, SP Amor, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Ferraz, V Araujo, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Armitage, LJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a direct measurement of the decay width of the top quark using tt¯ events in the lepton+jets final state. The data sample was collected by the ATLAS detector at the LHC in proton-proton collisions at a centre-of-mass energy of 8 TeV and corresponds to an integrated luminosity of 20.2 fb -1 . The decay width of the top quark is measured using a template fit to distributions of kinematic observables associated with the hadronically and semileptonically decaying top quarks. The result, Γt=1.76±0.33(stat.)-0.68+0.79(syst.)GeV for a top-quark mass of 172.5 GeV, is consistent with the prediction of the Standard Model.
Published: 2018

10. Measurement of the azimuthal anisotropy of charged particles produced in sNN = 5.02 TeV Pb+Pb collisions with the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adiguzel, A, Adye, T, Affolder, AA, Afik, Y, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmadov, F, Aielli, G, Akatsuka, S, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexopoulos, T, Alhroob, M, Ali, B, Alimonti, G, Alison, J, Alkire, SP, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, Amaral Coutinho, Y, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aparisi Pozo, JA, Aperio Bella, L, Arabidze, G, Araque, JP, Araujo Ferraz, V, Araujo Pereira, R, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Armbruster, AJ, Armitage, LJ, Armstrong, A, and Arnaez, O
Subjects: ATLAS Collaboration, nucl-ex, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Measurements of the azimuthal anisotropy in lead-lead collisions at sNN = 5.02 TeV are presented using a data sample corresponding to 0.49 nb-1 integrated luminosity collected by the ATLAS experiment at the LHC in 2015. The recorded minimum-bias sample is enhanced by triggers for "ultra-central" collisions, providing an opportunity to perform detailed study of flow harmonics in the regime where the initial state is dominated by fluctuations. The anisotropy of the charged-particle azimuthal angle distributions is characterized by the Fourier coefficients, v2 - v7 , which are measured using the two-particle correlation, scalar-product and event-plane methods. The goal of the paper is to provide measurements of the differential as well as integrated flow harmonics vn over wide ranges of the transverse momentum, 0.5
Published: 2018

11. Measurement of τ polarisation in Z/γ∗→ττ decays in proton-proton collisions at s=8 TeV with the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Afik, Y, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Alconada Verzini, MJ, Alderweireldt, SC, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Armitage, LJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a measurement of the polarisation of τ leptons produced in Z/γ∗→ττ decays which is performed with a dataset of proton-proton collisions at s=8 TeV, corresponding to an integrated luminosity of 20.2 fb -1 recorded with the ATLAS detector at the LHC in 2012. The Z/γ∗→ττ decays are reconstructed from a hadronically decaying τ lepton with a single charged particle in the final state, accompanied by a τ lepton that decays leptonically. The τ polarisation is inferred from the relative fraction of energy carried by charged and neutral hadrons in the hadronic τ decays. The polarisation is measured in a fiducial region that corresponds to the kinematic region accessible to this analysis. The τ polarisation extracted over the full phase space within the Z/γ∗ mass range of 66
Published: 2018

12. Operation and performance of the ATLAS Tile Calorimeter in Run 1.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Abhayasinghe, DK, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adiguzel, A, Adye, T, Affolder, AA, Afik, Y, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Alconada Verzini, MJ, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Alimonti, G, Alison, J, Alkire, SP, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, Amaral Coutinho, Y, Ambroz, L, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amrouche, CS, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Anelli, CR, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Anthony, MT, Antonelli, M, Antrim, DJA, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Pereira, R Araujo, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, and Armbruster, AJ
Subjects: ATLAS Collaboration, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The Tile Calorimeter is the hadron calorimeter covering the central region of the ATLAS experiment at the Large Hadron Collider. Approximately 10,000 photomultipliers collect light from scintillating tiles acting as the active material sandwiched between slabs of steel absorber. This paper gives an overview of the calorimeter's performance during the years 2008-2012 using cosmic-ray muon events and proton-proton collision data at centre-of-mass energies of 7 and 8 TeV with a total integrated luminosity of nearly 30 fb -1 . The signal reconstruction methods, calibration systems as well as the detector operation status are presented. The energy and time calibration methods performed excellently, resulting in good stability of the calorimeter response under varying conditions during the LHC Run 1. Finally, the Tile Calorimeter response to isolated muons and hadrons as well as to jets from proton-proton collisions is presented. The results demonstrate excellent performance in accord with specifications mentioned in the Technical Design Report.
Published: 2018

13. Measurement of quarkonium production in proton-lead and proton-proton collisions at 5.02TeV with the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akimov, AV, Alberghi, GL, Albert, J, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, 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, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Armitage, LJ, Arnaez, O, and Arnold, H
Subjects: ATLAS Collaboration, nucl-ex, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The modification of the production of J/ψ , ψ(2S) , and Υ(nS) ( n=1,2,3 ) in p+Pb collisions with respect to their production in pp collisions has been studied. The p+Pb and pp datasets used in this paper correspond to integrated luminosities of 28nb-1 and 25pb-1 respectively, collected in 2013 and 2015 by the ATLAS detector at the LHC, both at a centre-of-mass energy per nucleon pair of 5.02 TeV. The quarkonium states are reconstructed in the dimuon decay channel. The yields of J/ψ and ψ(2S) are separated into prompt and non-prompt sources. The measured quarkonium differential cross sections are presented as a function of rapidity and transverse momentum, as is the nuclear modification factor, RpPb for J/ψ and Υ(nS) . No significant modification of the J/ψ production is observed while Υ(nS) production is found to be suppressed at low transverse momentum in p+Pb collisions relative to pp collisions. The production of excited charmonium and bottomonium states is found to be suppressed relative to that of the ground states in central p+Pb collisions.
Published: 2018

14. Measurement of colour flow using jet-pull observables in tt¯ events with the ATLAS experiment at s=13TeV.

Author: Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Afik, Y, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahmadov, F, Aielli, G, Akatsuka, S, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Verzini, MJ Alconada, Alderweireldt, S, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Alimonti, G, Alison, J, Alkire, SP, Allaire, C, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, Coutinho, Y Amaral, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJA, Anulli, F, Aoki, M, Bella, L Aperio, Arabidze, G, Arai, Y, Araque, JP, Ferraz, V Araujo, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Armbruster, AJ, Armitage, LJ, Arnaez, O, Arnold, H, Arratia, M, Arslan, O, Artamonov, A, Artoni, G, and Artz, S
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Previous studies have shown that weighted angular moments derived from jet constituents encode the colour connections between partons that seed the jets. This paper presents measurements of two such distributions, the jet-pull angle and jet-pull magnitude, both of which are derived from the jet-pull angular moment. The measurement is performed in tt¯ events with one leptonically decaying W boson and one hadronically decaying W boson, using 36.1fb-1 of pp collision data recorded by the ATLAS detector at s=13TeV delivered by the Large Hadron Collider. The observables are measured for two dijet systems, corresponding to the colour-connected daughters of the W boson and the two b-jets from the top-quark decays, which are not expected to be colour connected. To allow the comparison of the measured distributions to colour model predictions, the measured distributions are unfolded to particle level, after correcting for experimental effects introduced by the detector. While good agreement can be found for some combinations of predictions and observables, none of the predictions describes the data well across all observables.
Published: 2018

15. Development of 100Mo -containing scintillating bolometers for a high-sensitivity neutrinoless double-beta decay search.

Author: Armengaud, E, Augier, C, Barabash, AS, Beeman, JW, Bekker, TB, Bellini, F, Benoît, A, Bergé, L, Bergmann, T, Billard, J, Boiko, RS, Broniatowski, A, Brudanin, V, Camus, P, Capelli, S, Cardani, L, Casali, N, Cazes, A, Chapellier, M, Charlieux, F, Chernyak, DM, de Combarieu, M, Coron, N, Danevich, FA, Dafinei, I, Jesus, M De, Devoyon, L, Domizio, S Di, Dumoulin, L, Eitel, K, Enss, C, Ferroni, F, Fleischmann, A, Foerster, N, Gascon, J, Gastaldo, L, Gironi, L, Giuliani, A, Grigorieva, VD, Gros, M, Hehn, L, Hervé, S, Humbert, V, Ivannikova, NV, Ivanov, IM, Jin, Y, Juillard, A, Kleifges, M, Kobychev, VV, Konovalov, SI, Koskas, F, Kozlov, V, Kraus, H, Kudryavtsev, VA, Laubenstein, M, Sueur, H Le, Loidl, M, Magnier, P, Makarov, EP, Mancuso, M, de Marcillac, P, Marnieros, S, Marrache-Kikuchi, C, Nagorny, S, Navick, X-F, Nikolaichuk, MO, Nones, C, Novati, V, Olivieri, E, Pagnanini, L, Pari, P, Pattavina, L, Pavan, M, Paul, B, Penichot, Y, Pessina, G, Piperno, G, Pirro, S, Plantevin, O, Poda, DV, Queguiner, E, Redon, T, Rodrigues, M, Rozov, S, Rusconi, C, Sanglard, V, Schäffner, K, Scorza, S, Shlegel, VN, Siebenborn, B, Strazzer, O, Tcherniakhovski, D, Tomei, C, Tretyak, VI, Umatov, VI, Vagneron, L, Vasiliev, Ya V, Velázquez, M, Vignati, M, and Weber, M
Subjects: Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: This paper reports on the development of a technology involving 100Mo -enriched scintillating bolometers, compatible with the goals of CUPID, a proposed next-generation bolometric experiment to search for neutrinoless double-beta decay. Large mass ( ∼1kg ), high optical quality, radiopure 100Mo -containing zinc and lithium molybdate crystals have been produced and used to develop high performance single detector modules based on 0.2-0.4 kg scintillating bolometers. In particular, the energy resolution of the lithium molybdate detectors near the Q-value of the double-beta transition of 100Mo (3034 keV) is 4-6 keV FWHM. The rejection of the α -induced dominant background above 2.6 MeV is better than 8σ . Less than 10μBq/kg activity of 232Th(228Th) and 226Ra in the crystals is ensured by boule recrystallization. The potential of 100Mo -enriched scintillating bolometers to perform high sensitivity double-beta decay searches has been demonstrated with only 10kg×d exposure: the two neutrino double-beta decay half-life of 100Mo has been measured with the up-to-date highest accuracy as T1/2 = [6.90 ± 0.15(stat.) ± 0.37(syst.)] ×1018years . Both crystallization and detector technologies favor lithium molybdate, which has been selected for the ongoing construction of the CUPID-0/Mo demonstrator, containing several kg of 100Mo .
Published: 2017

16. Measurement of the νμ energy spectrum with IceCube-79: IceCube Collaboration.

Author: Aartsen, MG, Ackermann, M, Adams, J, Aguilar, JA, Ahlers, M, Ahrens, M, Al Samarai, I, Altmann, D, Andeen, K, Anderson, T, Ansseau, I, Anton, G, Archinger, M, Argüelles, C, Auffenberg, J, Axani, S, Bagherpour, H, Bai, X, Barwick, SW, Baum, V, Bay, R, Beatty, JJ, Becker Tjus, J, Becker, K-H, BenZvi, S, Berley, D, Bernardini, E, Besson, DZ, Binder, G, Bindig, D, Blaufuss, E, Blot, S, Bohm, C, Börner, M, Bos, F, Bose, D, Böser, S, Botner, O, Bradascio, F, Braun, J, Brayeur, L, Bretz, H-P, Bron, S, Burgman, A, Carver, T, Casier, M, Cheung, E, Chirkin, D, Christov, A, Clark, K, Classen, L, Coenders, S, Collin, GH, Conrad, JM, Cowen, DF, Cross, R, Day, M, de André, JPAM, De Clercq, C, Del Pino Rosendo, E, Dembinski, H, De Ridder, S, Desiati, P, de Vries, KD, de Wasseige, G, de With, M, DeYoung, T, Díaz-Vélez, JC, di Lorenzo, V, Dujmovic, H, Dumm, JP, Dunkman, M, Eberhardt, B, Ehrhardt, T, Eichmann, B, Eller, P, Euler, S, Evenson, PA, Fahey, S, Fazely, AR, Feintzeig, J, Felde, J, Filimonov, K, Finley, C, Flis, S, Fösig, C-C, Franckowiak, A, Friedman, E, Fuchs, T, Gaisser, TK, Gallagher, J, Gerhardt, L, Ghorbani, K, Giang, W, Gladstone, L, Glauch, T, Glüsenkamp, T, Goldschmidt, A, Gonzalez, JG, and Grant, D
Subjects: astro-ph.HE, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The νμ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E ν -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9σ in four adjacent bins for neutrino energies Eν≥177.8TeV . The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.
Published: 2017

17. Search for triboson [Formula: see text] production in pp collisions at [Formula: see text] [Formula: see text] with the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, 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, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, M, Gonzalez, B Alvarez, Piqueras, D Álvarez, Alviggi, MG, Amadio, BT, Amako, K, Coutinho, Y Amaral, 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, Antel, C, Antonelli, M, Antonov, A, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Armitage, LJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper reports a search for triboson [Formula: see text] production in two decay channels ([Formula: see text] and [Formula: see text] with [Formula: see text]) in proton-proton collision data corresponding to an integrated luminosity of 20.3 [Formula: see text] at a centre-of-mass energy of 8 [Formula: see text] with the ATLAS detector at the Large Hadron Collider. Events with exactly three charged leptons, or two leptons with the same electric charge in association with two jets, are selected. The total number of events observed in data is consistent with the Standard Model (SM) predictions. The observed 95% confidence level upper limit on the SM [Formula: see text] production cross section is found to be 730 fb with an expected limit of 560 fb in the absence of SM [Formula: see text] production. Limits are also set on WWWW anomalous quartic gauge couplings.
Published: 2017

18. Measurement of the W boson polarisation in [Formula: see text] events from pp collisions at [Formula: see text] = 8 TeV in the lepton + jets channel with ATLAS.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Affolder, AA, Agatonovic-Jovin, T, 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, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, M, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, 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, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Armitage, LJ, Arnaez, O, Arnold, H, and Arratia, M
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a measurement of the polarisation of W bosons from [Formula: see text] decays, reconstructed in events with one high-[Formula: see text] lepton and at least four jets. Data from pp collisions at the LHC were collected at [Formula: see text] = 8 TeV and correspond to an integrated luminosity of 20.2 fb[Formula: see text]. The angle [Formula: see text] between the b-quark from the top quark decay and a direct W boson decay product in the W boson rest frame is sensitive to the W boson polarisation. Two different W decay products are used as polarisation analysers: the charged lepton and the down-type quark for the leptonically and hadronically decaying W boson, respectively. The most precise measurement of the W boson polarisation via the distribution of [Formula: see text] is obtained using the leptonic analyser and events in which at least two of the jets are tagged as b-quark jets. The fitted fractions of longitudinal, left- and right-handed polarisation states are [Formula: see text], [Formula: see text] and [Formula: see text], and are the most precisely measured W boson polarisation fractions to date. Limits on anomalous couplings of the Wtb vertex are set.
Published: 2017

19. Measurement of prompt and nonprompt [Formula: see text] production in [Formula: see text] and [Formula: see text] collisions at [Formula: see text].

Author: Sirunyan, AM, Tumasyan, A, Adam, W, Asilar, E, Bergauer, T, Brandstetter, J, Brondolin, E, Dragicevic, M, Erö, J, Flechl, M, Friedl, M, Frühwirth, R, Ghete, VM, Hartl, C, Hörmann, N, Hrubec, J, Jeitler, M, König, A, Krätschmer, I, Liko, D, Matsushita, T, Mikulec, I, Rabady, D, Rad, N, Rahbaran, B, Rohringer, H, Schieck, J, Strauss, J, Waltenberger, W, Wulz, C-E, Dvornikov, O, Makarenko, V, Mossolov, V, Suarez Gonzalez, J, Zykunov, V, Shumeiko, N, Alderweireldt, S, De Wolf, EA, Janssen, X, Lauwers, J, Van De Klundert, M, Van Haevermaet, H, Van Mechelen, P, Van Remortel, N, Van Spilbeeck, A, Abu Zeid, S, Blekman, F, D'Hondt, J, Daci, N, De Bruyn, I, Deroover, K, Lowette, S, Moortgat, S, Moreels, L, Olbrechts, A, Python, Q, Skovpen, K, Tavernier, S, Van Doninck, W, Van Mulders, P, Van Parijs, I, Brun, H, Clerbaux, B, De Lentdecker, G, Delannoy, H, Fasanella, G, Favart, L, Goldouzian, R, Grebenyuk, A, Karapostoli, G, Lenzi, T, Léonard, A, Luetic, J, Maerschalk, T, Marinov, A, Randle-Conde, A, Seva, T, Vander Velde, C, Vanlaer, P, Vannerom, D, Yonamine, R, Zenoni, F, Zhang, F, Cimmino, A, Cornelis, T, Dobur, D, Fagot, A, Gul, M, Khvastunov, I, Poyraz, D, Salva, S, Schöfbeck, R, Tytgat, M, Van Driessche, W, Yazgan, E, Zaganidis, N, Bakhshiansohi, H, Beluffi, C, Bondu, O, and Brochet, S
Subjects: CMS Collaboration, Genetics, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper reports the measurement of [Formula: see text] meson production in proton-proton ([Formula: see text]) and proton-lead ([Formula: see text]) collisions at a center-of-mass energy per nucleon pair of [Formula: see text] by the CMS experiment at the LHC. The data samples used in the analysis correspond to integrated luminosities of 28[Formula: see text] and 35[Formula: see text] for [Formula: see text] and [Formula: see text] collisions, respectively. Prompt and nonprompt [Formula: see text] mesons, the latter produced in the decay of [Formula: see text] hadrons, are measured in their dimuon decay channels. Differential cross sections are measured in the transverse momentum range of [Formula: see text], and center-of-mass rapidity ranges of [Formula: see text] ([Formula: see text]) and [Formula: see text] ([Formula: see text]). The nuclear modification factor, [Formula: see text], is measured as a function of both [Formula: see text] and [Formula: see text]. Small modifications to the [Formula: see text] cross sections are observed in [Formula: see text] relative to [Formula: see text] collisions. The ratio of [Formula: see text] production cross sections in [Formula: see text]-going and Pb-going directions, [Formula: see text], studied as functions of [Formula: see text] and [Formula: see text], shows a significant decrease for increasing transverse energy deposited at large pseudorapidities. These results, which cover a wide kinematic range, provide new insight on the role of cold nuclear matter effects on prompt and nonprompt [Formula: see text] production.
Published: 2017

20. Identification and rejection of pile-up jets at high pseudorapidity with the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, M, Gonzalez, B Alvarez, Piqueras, D Álvarez, Alviggi, MG, Amadio, BT, Coutinho, Y Amaral, Amelung, C, Amidei, D, Santos, SP Amor Dos, Amorim, A, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Bella, L Aperio, Arabidze, G, Arai, Y, Araque, JP, Ferraz, V Araujo, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Armitage, LJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The rejection of forward jets originating from additional proton-proton interactions (pile-up) is crucial for a variety of physics analyses at the LHC, including Standard Model measurements and searches for physics beyond the Standard Model. The identification of such jets is challenging due to the lack of track and vertex information in the pseudorapidity range |η|>2.5 . This paper presents a novel strategy for forward pile-up jet tagging that exploits jet shapes and topological jet correlations in pile-up interactions. Measurements of the per-jet tagging efficiency are presented using a data set of 3.2 fb -1 of proton-proton collisions at a centre-of-mass energy of 13 TeV collected with the ATLAS detector. The fraction of pile-up jets rejected in the range 2.5
Published: 2017

21. Electron efficiency measurements with the ATLAS detector using 2012 LHC proton-proton collision data.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Affolder, AA, Agatonovic-Jovin, T, 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, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, M, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, 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, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, 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: ATLAS Collaboration, Bioengineering, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper describes the algorithms for the reconstruction and identification of electrons in the central region of the ATLAS detector at the Large Hadron Collider (LHC). These algorithms were used for all ATLAS results with electrons in the final state that are based on the 2012 pp collision data produced by the LHC at [Formula: see text] = 8 [Formula: see text]. The efficiency of these algorithms, together with the charge misidentification rate, is measured in data and evaluated in simulated samples using electrons from [Formula: see text], [Formula: see text] and [Formula: see text] decays. For these efficiency measurements, the full recorded data set, corresponding to an integrated luminosity of 20.3 fb[Formula: see text], is used. Based on a new reconstruction algorithm used in 2012, the electron reconstruction efficiency is 97% for electrons with [Formula: see text] [Formula: see text] and 99% at [Formula: see text] [Formula: see text]. Combining this with the efficiency of additional selection criteria to reject electrons from background processes or misidentified hadrons, the efficiency to reconstruct and identify electrons at the ATLAS experiment varies from 65 to 95%, depending on the transverse momentum of the electron and background rejection.
Published: 2017

22. Study of WWγ and WZγ production in pp collisions at s=8TeV and search for anomalous quartic gauge couplings with the ATLAS experiment.

Author: Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Alconada Verzini, MJ, Alderweireldt, SC, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Armitage, LJ, and Arnaez, O
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a study of WWγ and WZγ triboson production using events from proton-proton collisions at a centre-of-mass energy of s=8TeV recorded with the ATLAS detector at the LHC and corresponding to an integrated luminosity of 20.2 fb -1 . The WWγ production cross-section is determined using a final state containing an electron, a muon, a photon, and neutrinos ( eνμνγ ). Upper limits on the production cross-section of the eνμνγ final state and the WWγ and WZγ final states containing an electron or a muon, two jets, a photon, and a neutrino ( eνjjγ or μνjjγ ) are also derived. The results are compared to the cross-sections predicted by the Standard Model at next-to-leading order in the strong-coupling constant. In addition, upper limits on the production cross-sections are derived in a fiducial region optimised for a search for new physics beyond the Standard Model. The results are interpreted in the context of anomalous quartic gauge couplings using an effective field theory. Confidence intervals at 95% confidence level are derived for the 14 coupling coefficients to which WWγ and WZγ production are sensitive.
Published: 2017

23. Measurement of detector-corrected observables sensitive to the anomalous production of events with jets and large missing transverse momentum in pp collisions at s=13 TeV using the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, 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, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Armitage, LJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Observables sensitive to the anomalous production of events containing hadronic jets and missing momentum in the plane transverse to the proton beams at the Large Hadron Collider are presented. The observables are defined as a ratio of cross sections, for events containing jets and large missing transverse momentum to events containing jets and a pair of charged leptons from the decay of a Z/γ∗ boson. This definition minimises experimental and theoretical systematic uncertainties in the measurements. This ratio is measured differentially with respect to a number of kinematic properties of the hadronic system in two phase-space regions; one inclusive single-jet region and one region sensitive to vector-boson-fusion topologies. The data are found to be in agreement with the Standard Model predictions and used to constrain a variety of theoretical models for dark-matter production, including simplified models, effective field theory models, and invisible decays of the Higgs boson. The measurements use 3.2 fb -1 of proton-proton collision data recorded by the ATLAS experiment at a centre-of-mass energy of 13 TeV and are fully corrected for detector effects, meaning that the data can be used to constrain new-physics models beyond those shown in this paper.
Published: 2017

24. Performance of the ATLAS trigger system in 2015.

Author: Atlas Collaboration, 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, Adachi, S, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Affolder, AA, Agatonovic-Jovin, T, 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, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, M, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, 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, Angerami, A, Anghinolfi, F, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, and Arik, M
Subjects: Atlas Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: During 2015 the ATLAS experiment recorded [Formula: see text] of proton-proton collision data at a centre-of-mass energy of [Formula: see text]. The ATLAS trigger system is a crucial component of the experiment, responsible for selecting events of interest at a recording rate of approximately 1 kHz from up to 40 MHz of collisions. This paper presents a short overview of the changes to the trigger and data acquisition systems during the first long shutdown of the LHC and shows the performance of the trigger system and its components based on the 2015 proton-proton collision data.
Published: 2017

25. Measurement of lepton differential distributions and the top quark mass in tt¯ production in pp collisions at s=8 TeV with the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Afik, Y, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Alconada Verzini, MJ, Alderweireldt, SC, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, Amaral Coutinho, Y, Amelung, C, Amidei, D, Amor Dos Santos, SP, Amoroso, S, Amundsen, G, Anastopoulos, C, Ancu, LS, Andari, N, Andeen, T, Anders, CF, Anders, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Armitage, LJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents single lepton and dilepton kinematic distributions measured in dileptonic tt¯ events produced in 20.2 fb-1 of s=8 TeV pp collisions recorded by the ATLAS experiment at the LHC. Both absolute and normalised differential cross-sections are measured, using events with an opposite-charge eμ pair and one or two b-tagged jets. The cross-sections are measured in a fiducial region corresponding to the detector acceptance for leptons, and are compared to the predictions from a variety of Monte Carlo event generators, as well as fixed-order QCD calculations, exploring the sensitivity of the cross-sections to the gluon parton distribution function. Some of the distributions are also sensitive to the top quark pole mass; a combined fit of NLO fixed-order predictions to all the measured distributions yields a top quark mass value of mtpole=173.2±0.9±0.8±1.2 GeV, where the three uncertainties arise from data statistics, experimental systematics, and theoretical sources.
Published: 2017

26. Reconstruction of primary vertices at the ATLAS experiment in Run 1 proton-proton collisions at the LHC.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agricola, J, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, 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, Santos, SP Amor Dos, 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, Antel, C, 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, and Arnold, H
Subjects: ATLAS Collaboration, Bioengineering, physics.ins-det, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents the method and performance of primary vertex reconstruction in proton-proton collision data recorded by the ATLAS experiment during Run 1 of the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of [Formula: see text] TeV. The performance has been measured as a function of the number of interactions per bunch crossing over a wide range, from one to seventy. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed. A longitudinal vertex position resolution of about [Formula: see text] is achieved for events with high multiplicity of reconstructed tracks. The transverse position resolution is better than [Formula: see text] and is dominated by the precision on the size of the luminous region. An analytical model is proposed to describe the primary vertex reconstruction efficiency as a function of the number of interactions per bunch crossing and of the longitudinal size of the luminous region. Agreement between the data and the predictions of this model is better than 3% up to seventy interactions per bunch crossing.
Published: 2017

27. Measurement of WW/WZ→ℓνqq' production with the hadronically decaying boson reconstructed as one or two jets in pp collisions at s=8TeV with ATLAS, and constraints on anomalous gauge couplings.

Author: Aaboud, M, Aad, G, Abbott, B, Abdinov, O, Abeloos, B, Abidi, SH, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adachi, S, Adamczyk, L, Adelman, J, Adersberger, M, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agheorghiesei, C, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akatsuka, S, Akerstedt, H, Åkesson, TPA, Akilli, E, Akimov, AV, Alberghi, GL, Albert, J, Albicocco, P, Alconada Verzini, MJ, Alderweireldt, SC, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, Aliev, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Alshehri, AA, Alstaty, MI, Alvarez Gonzalez, B, Álvarez Piqueras, D, Alviggi, MG, Amadio, BT, 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, JK, Anderson, KJ, Andreazza, A, Andrei, V, Angelidakis, S, Angelozzi, I, Angerami, A, Anisenkov, AV, Anjos, N, Annovi, A, Antel, C, Antonelli, M, Antonov, A, Antrim, DJ, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Araujo Ferraz, V, Arce, ATH, Ardell, RE, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, and Armitage, LJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a study of the production of WW or WZ boson pairs, with one W boson decaying to eν or μν and one W or Z boson decaying hadronically. The analysis uses 20.2fb-1 of s=8TeV pp collision data, collected by the ATLAS detector at the Large Hadron Collider. Cross-sections for WW / WZ production are measured in high- pT fiducial regions defined close to the experimental event selection. The cross-section is measured for the case where the hadronically decaying boson is reconstructed as two resolved jets, and the case where it is reconstructed as a single jet. The transverse momentum distribution of the hadronically decaying boson is used to search for new physics. Observations are consistent with the Standard Model predictions, and 95% confidence intervals are calculated for parameters describing anomalous triple gauge-boson couplings.
Published: 2017

28. First array of enriched Zn[Formula: see text]Se bolometers to search for double beta decay.

Author: Artusa, DR, Balzoni, A, Beeman, JW, Bellini, F, Biassoni, M, Brofferio, C, Camacho, A, Capelli, S, Cardani, L, Carniti, P, Casali, N, Cassina, L, Clemenza, M, Cremonesi, O, Cruciani, A, D'Addabbo, A, Dafinei, I, Di Domizio, S, di Vacri, ML, Ferroni, F, Gironi, L, Giuliani, A, Gotti, C, Keppel, G, Maino, M, Mancuso, M, Martinez, M, Morganti, S, Nagorny, S, Nastasi, M, Nisi, S, Nones, C, Orio, F, Orlandi, D, Pagnanini, L, Pallavicini, M, Palmieri, V, Pattavina, L, Pavan, M, Pessina, G, Pettinacci, V, Pirro, S, Pozzi, S, Previtali, E, Puiu, A, Rusconi, C, Schäffner, K, Tomei, C, Vignati, M, and Zolotarova, A
Subjects: Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: The R&D activity performed during the last years proved the potential of ZnSe scintillating bolometers to the search for neutrino-less double beta decay, motivating the realization of the first large-mass experiment based on this technology: CUPID-0. The isotopic enrichment in [Formula: see text]Se, the Zn[Formula: see text]Se crystals growth, as well as the light detectors production have been accomplished, and the experiment is now in construction at Laboratori Nazionali del Gran Sasso (Italy). In this paper we present the results obtained testing the first three Zn[Formula: see text]Se crystals operated as scintillating bolometers, and we prove that their performance in terms of energy resolution, background rejection capability and intrinsic radio-purity complies with the requirements of CUPID-0.
Published: 2016

29. Reconstruction of hadronic decay products of tau leptons with the ATLAS experiment.

Author: Atlas Collaboration, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, 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, Alimonti, G, Alio, L, Alison, J, Alkire, SP, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, 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, Amram, N, 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, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, and Arnold, H
Subjects: Atlas Collaboration, Bioengineering, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a new method of reconstructing the individual charged and neutral hadrons in tau decays with the ATLAS detector. The reconstructed hadrons are used to classify the decay mode and to calculate the visible four-momentum of reconstructed tau candidates, significantly improving the resolution with respect to the calibration in the existing tau reconstruction. The performance of the reconstruction algorithm is optimised and evaluated using simulation and validated using samples of [Formula: see text] and [Formula: see text]+jets events selected from proton-proton collisions at a centre-of-mass energy [Formula: see text], corresponding to an integrated luminosity of 5 [Formula: see text].
Published: 2016

30. A new method to distinguish hadronically decaying boosted Z bosons from W bosons using the ATLAS detector.

Author: Atlas Collaboration, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, 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, Alimonti, G, Alio, L, Alison, J, Alkire, SP, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, 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, Amram, N, 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, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, and Arnold, H
Subjects: Atlas Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The distribution of particles inside hadronic jets produced in the decay of boosted W and Z bosons can be used to discriminate such jets from the continuum background. Given that a jet has been identified as likely resulting from the hadronic decay of a boosted W or Z boson, this paper presents a technique for further differentiating Z bosons from W bosons. The variables used are jet mass, jet charge, and a b-tagging discriminant. A likelihood tagger is constructed from these variables and tested in the simulation of [Formula: see text] for bosons in the transverse momentum range 200 GeV [Formula: see text] 400 GeV in [Formula: see text] TeV pp collisions with the ATLAS detector at the LHC. For Z-boson tagging efficiencies of [Formula: see text], 50, and [Formula: see text], one can achieve [Formula: see text]-boson tagging rejection factors ([Formula: see text]) of 1.7, 8.3 and 1000, respectively. It is not possible to measure these efficiencies in the data due to the lack of a pure sample of high [Formula: see text], hadronically decaying Z bosons. However, the modelling of the tagger inputs for boosted W bosons is studied in data using a [Formula: see text]-enriched sample of events in 20.3 fb[Formula: see text] of data at [Formula: see text] TeV. The inputs are well modelled within uncertainties, which builds confidence in the expected tagger performance.
Published: 2016

31. Measurement of the charged-particle multiplicity inside jets from [Formula: see text][Formula: see text] pp collisions with the ATLAS detector.

Author: Atlas Collaboration, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, Abolins, M, 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, Alconada Verzini, MJ, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Alimonti, G, Alison, J, Alkire, SP, Allbrooke, BMM, Allen, BW, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, 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, Amram, N, 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, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Armitage, LJ, and Arnaez, O
Subjects: Atlas Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The number of charged particles inside jets is a widely used discriminant for identifying the quark or gluon nature of the initiating parton and is sensitive to both the perturbative and non-perturbative components of fragmentation. This paper presents a measurement of the average number of charged particles with [Formula: see text] [Formula: see text] inside high-momentum jets in dijet events using 20.3 fb[Formula: see text] of data recorded with the ATLAS detector in pp collisions at [Formula: see text] [Formula: see text] collisions at the LHC. The jets considered have transverse momenta from 50 [Formula: see text] up to and beyond 1.5 [Formula: see text]. The reconstructed charged-particle track multiplicity distribution is unfolded to remove distortions from detector effects and the resulting charged-particle multiplicity is compared to several models. Furthermore, quark and gluon jet fractions are used to extract the average charged-particle multiplicity for quark and gluon jets separately.
Published: 2016

32. Charged-particle distributions in pp interactions at [Formula: see text] measured with the ATLAS detector.

Author: Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, Abolins, M, 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, 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, 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, Amram, N, 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, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, 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, and Arratia, M
Subjects: ATLAS Collaboration, Bioengineering, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents measurements of distributions of charged particles which are produced in proton-proton collisions at a centre-of-mass energy of [Formula: see text] and recorded by the ATLAS detector at the LHC. A special dataset recorded in 2012 with a small number of interactions per beam crossing (below 0.004) and corresponding to an integrated luminosity of 160 [Formula: see text] was used. A minimum-bias trigger was utilised to select a data sample of more than 9 million collision events. The multiplicity, pseudorapidity, and transverse momentum distributions of charged particles are shown in different regions of kinematics and charged-particle multiplicity, including measurements of final states at high multiplicity. The results are corrected for detector effects and are compared to the predictions of various Monte Carlo event generator models which simulate the full hadronic final state.
Published: 2016

33. Search for the Higgs boson produced in association with a W boson and decaying to four b-quarks via two spin-zero particles in pp collisions at 13 TeV with the ATLAS detector.

Author: Aaboud, M, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Abeloos, B, Aben, R, AbouZeid, OS, Abraham, NL, Abramowicz, H, Abreu, H, Abreu, R, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Adelman, J, Adomeit, S, Adye, T, Affolder, AA, Agatonovic-Jovin, T, Agricola, J, Aguilar-Saavedra, JA, Ahlen, SP, Ahmadov, F, Aielli, G, Akerstedt, H, Åkesson, TPA, Akimov, AV, Alberghi, GL, Albert, J, Albrand, S, Verzini, MJ Alconada, Aleksa, M, Aleksandrov, IN, Alexa, C, Alexander, G, Alexopoulos, T, Alhroob, M, Ali, B, 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, Santos, SP Amor Dos, 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, Antel, C, 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, and Arnold, H
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a dedicated search for exotic decays of the Higgs boson to a pair of new spin-zero particles, [Formula: see text], where the particle a decays to b-quarks and has a mass in the range of 20-60 GeV. The search is performed in events where the Higgs boson is produced in association with a [Formula: see text] boson, giving rise to a signature of a lepton (electron or muon), missing transverse momentum, and multiple jets from b-quark decays. The analysis is based on the full dataset of pp collisions at [Formula: see text] recorded in 2015 by the ATLAS detector at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 3.2 [Formula: see text]. No significant excess of events above the Standard Model prediction is observed, and a [Formula: see text] confidence-level upper limit is derived for the product of the production cross section for [Formula: see text] times the branching ratio for the decay [Formula: see text]. The upper limit ranges from 6.2 pb for an a-boson mass [Formula: see text] to 1.5 pb for [Formula: see text].
Published: 2016

34. Measurement of the charge asymmetry in top-quark pair production in the lepton-plus-jets final state in pp collision data at [Formula: see text] with the ATLAS detector.

Author: Atlas Collaboration, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, 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, Alimonti, G, Alio, L, Alison, J, Alkire, SP, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, 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, Amram, N, 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, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, Arnold, H, and Arratia, M
Subjects: Atlas Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper reports inclusive and differential measurements of the [Formula: see text] charge asymmetry [Formula: see text] in [Formula: see text] of [Formula: see text][Formula: see text] collisions recorded by the ATLAS experiment at the Large Hadron Collider at CERN. Three differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the [Formula: see text] system. The [Formula: see text] pairs are selected in the single-lepton channels (e or [Formula: see text]) with at least four jets, and a likelihood fit is used to reconstruct the [Formula: see text] event kinematics. A Bayesian unfolding procedure is performed to infer the asymmetry at parton level from the observed data distribution. The inclusive [Formula: see text] charge asymmetry is measured to be [Formula: see text] (stat. [Formula: see text] syst.). The inclusive and differential measurements are compatible with the values predicted by the Standard Model.
Published: 2016

35. Performance of pile-up mitigation techniques for jets in [Formula: see text] collisions at [Formula: see text] TeV using the ATLAS detector.

Author: Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, 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, Alimonti, G, Alio, L, Alison, J, Alkire, SP, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, 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, Amram, N, 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, 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, Arratia, M, Arslan, O, and Artamonov, A
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The large rate of multiple simultaneous proton-proton interactions, or pile-up, generated by the Large Hadron Collider in Run 1 required the development of many new techniques to mitigate the adverse effects of these conditions. This paper describes the methods employed in the ATLAS experiment to correct for the impact of pile-up on jet energy and jet shapes, and for the presence of spurious additional jets, with a primary focus on the large 20.3 [Formula: see text] data sample collected at a centre-of-mass energy of [Formula: see text]. The energy correction techniques that incorporate sophisticated estimates of the average pile-up energy density and tracking information are presented. Jet-to-vertex association techniques are discussed and projections of performance for the future are considered. Lastly, the extension of these techniques to mitigate the effect of pile-up on jet shapes using subtraction and grooming procedures is presented.
Published: 2016

36. Identification of boosted, hadronically decaying W bosons and comparisons with ATLAS data taken at [Formula: see text] TeV.

Author: Atlas Collaboration, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, 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, Alimonti, G, Alio, L, Alison, J, Alkire, SP, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, 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, Amram, N, 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, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, Arabidze, G, Arai, Y, Araque, JP, Arce, ATH, Arduh, FA, Arguin, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, Arnold, H, and Arratia, M
Subjects: Atlas Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper reports a detailed study of techniques for identifying boosted, hadronically decaying W bosons using 20.3 fb[Formula: see text] of proton-proton collision data collected by the ATLAS detector at the LHC at a centre-of-mass energy [Formula: see text]. A range of techniques for optimising the signal jet mass resolution are combined with various jet substructure variables. The results of these studies in Monte Carlo simulations show that a simple pairwise combination of groomed jet mass and one substructure variable can provide a 50 % efficiency for identifying W bosons with transverse momenta larger than 200 GeV while maintaining multijet background efficiencies of 2-4 % for jets with the same transverse momentum. These signal and background efficiencies are confirmed in data for a selection of tagging techniques.
Published: 2016

37. TeO[Formula: see text] bolometers with Cherenkov signal tagging: towards next-generation neutrinoless double-beta decay experiments.

Author: Casali, N, Vignati, M, Beeman, JW, Bellini, F, Cardani, L, Dafinei, I, Di Domizio, S, Ferroni, F, Gironi, L, Nagorny, S, Orio, F, Pattavina, L, Pessina, G, Piperno, G, Pirro, S, Rusconi, C, Schäffner, K, and Tomei, C
Subjects: Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: CUORE, an array of 988 TeO[Formula: see text] bolometers, is about to be one of the most sensitive experiments searching for neutrinoless double-beta decay. Its sensitivity could be further improved by removing the background from [Formula: see text] radioactivity. A few years ago it was pointed out that the signal from [Formula: see text]s can be tagged by detecting the emitted Cherenkov light, which is not produced by [Formula: see text]s. In this paper we confirm this possibility. For the first time we measured the Cherenkov light emitted by a CUORE crystal, and found it to be 100 eV at the [Formula: see text]-value of the decay. To completely reject the [Formula: see text] background, we compute that one needs light detectors with baseline noise below 20 eV RMS, a value which is 3-4 times smaller than the average noise of the bolometric light detectors we are using. We point out that an improved light detector technology must be developed to obtain TeO[Formula: see text] bolometric experiments able to probe the inverted hierarchy of neutrino masses.
Published: 2015

38. Two-particle Bose-Einstein correlations in pp collisions at [Formula: see text] 0.9 and 7 TeV measured 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, 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: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: The paper presents studies of Bose-Einstein Correlations (BEC) for pairs of like-sign charged particles measured in the kinematic range [Formula: see text] 100 MeV and [Formula: see text] 2.5 in proton collisions at centre-of-mass energies of 0.9 and 7 TeV with the ATLAS detector at the CERN Large Hadron Collider. The integrated luminosities are approximately 7 [Formula: see text]b[Formula: see text], 190 [Formula: see text]b[Formula: see text] and 12.4 nb[Formula: see text] for 0.9 TeV, 7 TeV minimum-bias and 7 TeV high-multiplicity data samples, respectively. The multiplicity dependence of the BEC parameters characterizing the correlation strength and the correlation source size are investigated for charged-particle multiplicities of up to 240. A saturation effect in the multiplicity dependence of the correlation source size parameter is observed using the high-multiplicity 7 TeV data sample. The dependence of the BEC parameters on the average transverse momentum of the particle pair is also investigated.
Published: 2015

39. Measurement of the inclusive 3-jet production differential cross section in proton-proton collisions at 7 TeV and determination of the strong coupling constant in the TeV range.

Author: Khachatryan, V, Sirunyan, AM, Tumasyan, A, Adam, W, Bergauer, T, Dragicevic, M, Erö, J, Fabjan, C, Friedl, M, Frühwirth, R, Ghete, VM, Hartl, C, Hörmann, N, Hrubec, J, Jeitler, M, Kiesenhofer, W, Knünz, V, Krammer, M, Krätschmer, I, Liko, D, Mikulec, I, Rabady, D, Rahbaran, B, Rohringer, H, Schöfbeck, R, Strauss, J, Taurok, A, Treberer-Treberspurg, W, Waltenberger, W, Wulz, C-E, Mossolov, V, Shumeiko, N, Suarez Gonzalez, J, Alderweireldt, S, Bansal, M, Bansal, S, Cornelis, T, De Wolf, EA, Janssen, X, Knutsson, A, Luyckx, S, Ochesanu, S, Rougny, R, Van De Klundert, M, Van Haevermaet, H, Van Mechelen, P, Van Remortel, N, Van Spilbeeck, A, Blekman, F, Blyweert, S, D'Hondt, J, Daci, N, Heracleous, N, Keaveney, J, Lowette, S, Maes, M, Olbrechts, A, Python, Q, Strom, D, Tavernier, S, Van Doninck, W, Van Mulders, P, Van Onsem, GP, Villella, I, Caillol, C, Clerbaux, B, De Lentdecker, G, Dobur, D, Favart, L, Gay, APR, Grebenyuk, A, Léonard, A, Mohammadi, A, Perniè, L, Reis, T, Seva, T, Thomas, L, Vander Velde, C, Vanlaer, P, Wang, J, Zenoni, F, Adler, V, Beernaert, K, Benucci, L, Cimmino, A, Costantini, S, Crucy, S, Dildick, S, Fagot, A, Garcia, G, Mccartin, J, Ocampo Rios, AA, Ryckbosch, D, Salva Diblen, S, Sigamani, M, Strobbe, N, Thyssen, F, Tytgat, M, Yazgan, E, and Zaganidis, N
Subjects: 3-jet mass, Alpha-S, CMS, Jets, PDF, Physics, QCD, Strong coupling constant, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: This paper presents a measurement of the inclusive 3-jet production differential cross section at a proton-proton centre-of-mass energy of 7 TeV using data corresponding to an integrated luminosity of 5[Formula: see text]collected with the CMS detector. The analysis is based on the three jets with the highest transverse momenta. The cross section is measured as a function of the invariant mass of the three jets in a range of 445-3270 GeV and in two bins of the maximum rapidity of the jets up to a value of 2. A comparison between the measurement and the prediction from perturbative QCD at next-to-leading order is performed. Within uncertainties, data and theory are in agreement. The sensitivity of the observable to the strong coupling constant [Formula: see text] is studied. A fit to all data points with 3-jet masses larger than 664 GeV gives a value of the strong coupling constant of [Formula: see text].
Published: 2015

40. Distributions of topological observables in inclusive three- and four-jet events in pp collisions at [Formula: see text][Formula: see text].

Author: Khachatryan, V, Sirunyan, AM, Tumasyan, A, Adam, W, Bergauer, T, Dragicevic, M, Erö, J, Friedl, M, Frühwirth, R, Ghete, VM, Hartl, C, Hörmann, N, Hrubec, J, Jeitler, M, Kiesenhofer, W, Knünz, V, Krammer, M, Krätschmer, I, Liko, D, Mikulec, I, Rabady, D, Rahbaran, B, Rohringer, H, Schöfbeck, R, Strauss, J, Treberer-Treberspurg, W, Waltenberger, W, Wulz, C-E, Mossolov, V, Shumeiko, N, Suarez Gonzalez, J, Alderweireldt, S, Bansal, S, Cornelis, T, De Wolf, EA, Janssen, X, Knutsson, A, Lauwers, J, Luyckx, S, Ochesanu, S, Rougny, R, Van De Klundert, M, Van Haevermaet, H, Van Mechelen, P, Van Remortel, N, Van Spilbeeck, A, Blekman, F, Blyweert, S, D'Hondt, J, Daci, N, Heracleous, N, Keaveney, J, Lowette, S, Maes, M, Olbrechts, A, Python, Q, Strom, D, Tavernier, S, Van Doninck, W, Van Mulders, P, Van Onsem, GP, Villella, I, Caillol, C, Clerbaux, B, De Lentdecker, G, Dobur, D, Favart, L, Gay, APR, Grebenyuk, A, Léonard, A, Mohammadi, A, Perniè, L, Randle-Conde, A, Reis, T, Seva, T, Thomas, L, Vander Velde, C, Vanlaer, P, Wang, J, Zenoni, F, Adler, V, Beernaert, K, Benucci, L, Cimmino, A, Costantini, S, Crucy, S, Dildick, S, Fagot, A, Garcia, G, Mccartin, J, Ocampo Rios, AA, Ryckbosch, D, Salva Diblen, S, Sigamani, M, Strobbe, N, Thyssen, F, Tytgat, M, Yazgan, E, Zaganidis, N, and Basegmez, S
Subjects: CMS Collaboration, hep-ex, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics, Nuclear & Particles Physics
Abstract: This paper presents distributions of topological observables in inclusive three- and four-jet events produced in pp collisions at a centre-of-mass energy of 7[Formula: see text] with a data sample collected by the CMS experiment corresponding to a luminosity of 5.1[Formula: see text]. The distributions are corrected for detector effects, and compared with several event generators based on two- and multi-parton matrix elements at leading order. Among the considered calculations, MadGraph interfaced with pythia6 displays the overall best agreement with data.
Published: 2015

41. Constraints on the off-shell Higgs boson signal strength in the high-mass ZZ and WW final states with the ATLAS detector.

Author: ATLAS Collaboration, Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, 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, 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, Alexopoulos, T, Alhroob, M, Alimonti, G, Alio, L, Alison, J, Alkire, SP, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, Alvarez Gonzalez, B, Piqueras, D Álvarez, 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, 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, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, Arnal, V, Arnold, H, and Arratia, M
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: Measurements of the ZZ and WW final states in the mass range above the [Formula: see text] and [Formula: see text] thresholds provide a unique opportunity to measure the off-shell coupling strength of the Higgs boson. This paper presents constraints on the off-shell Higgs boson event yields normalised to the Standard Model prediction (signal strength) in the [Formula: see text], [Formula: see text] and [Formula: see text] final states. The result is based on pp collision data collected by the ATLAS experiment at the LHC, corresponding to an integrated luminosity of 20.3 fb[Formula: see text] at a collision energy of [Formula: see text] TeV. Using the [Formula: see text] method, the observed 95 [Formula: see text] confidence level (CL) upper limit on the off-shell signal strength is in the range 5.1-8.6, with an expected range of 6.7-11.0. In each case the range is determined by varying the unknown [Formula: see text] and [Formula: see text] background K-factor from higher-order quantum chromodynamics corrections between half and twice the value of the known signal K-factor. Assuming the relevant Higgs boson couplings are independent of the energy scale of the Higgs boson production, a combination with the on-shell measurements yields an observed (expected) 95 [Formula: see text] CL upper limit on [Formula: see text] in the range 4.5-7.5 (6.5-11.2) using the same variations of the background K-factor. Assuming that the unknown [Formula: see text] background K-factor is equal to the signal K-factor, this translates into an observed (expected) 95 [Formula: see text] CL upper limit on the Higgs boson total width of 22.7 (33.0) MeV.
Published: 2015

42. Measurements of the [Formula: see text] production cross sections in association with jets with the ATLAS detector.

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, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents cross sections for the production of a [Formula: see text] boson in association with jets, measured in proton-proton collisions at [Formula: see text] with the ATLAS experiment at the large hadron collider. With an integrated luminosity of [Formula: see text], this data set allows for an exploration of a large kinematic range, including jet production up to a transverse momentum of [Formula: see text] and multiplicities up to seven associated jets. The production cross sections for [Formula: see text] bosons are measured in both the electron and muon decay channels. Differential cross sections for many observables are also presented including measurements of the jet observables such as the rapidities and the transverse momenta as well as measurements of event observables such as the scalar sums of the transverse momenta of the jets. The measurements are compared to numerous QCD predictions including next-to-leading-order perturbative calculations, resummation calculations and Monte Carlo generators.
Published: 2015

43. Search for resonant diboson production in the [Formula: see text] final state in [Formula: see text] collisions at [Formula: see text] TeV with the ATLAS detector.

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, Arik, M, and Armbruster, AJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper reports on a search for narrow resonances in diboson production in the [Formula: see text] final state using [Formula: see text] collision data corresponding to an integrated luminosity of [Formula: see text] fb[Formula: see text] collected at [Formula: see text] TeV with the ATLAS detector at the Large Hadron Collider. No significant excess of data events over the Standard Model expectation is observed. Upper limits at the 95 % confidence level are set on the production cross section times branching ratio for Kaluza-Klein gravitons predicted by the Randall-Sundrum model and for Extended Gauge Model [Formula: see text] bosons. These results lead to the exclusion of mass values below 740 and 1590 GeV for the graviton and [Formula: see text] boson respectively.
Published: 2015

44. Identification and energy calibration of hadronically decaying tau leptons with the ATLAS experiment in pp collisions at [Formula: see text][Formula: see text].

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, J-F, Argyropoulos, S, Arik, M, Armbruster, AJ, Arnaez, O, and Arnal, V
Subjects: Atlas Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper describes the trigger and offline reconstruction, identification and energy calibration algorithms for hadronic decays of tau leptons employed for the data collected from pp collisions in 2012 with the ATLAS detector at the LHC center-of-mass energy [Formula: see text] [Formula: see text]. The performance of these algorithms is measured in most cases with [Formula: see text] decays to tau leptons using the full 2012 dataset, corresponding to an integrated luminosity of 20.3 fb[Formula: see text]. An uncertainty on the offline reconstructed tau energy scale of 2-4 %, depending on transverse energy and pseudorapidity, is achieved using two independent methods. The offline tau identification efficiency is measured with a precision of 2.5 % for hadronically decaying tau leptons with one associated track, and of 4 % for the case of three associated tracks, inclusive in pseudorapidity and for a visible transverse energy greater than 20 [Formula: see text]. For hadronic tau lepton decays selected by offline algorithms, the tau trigger identification efficiency is measured with a precision of 2-8 %, depending on the transverse energy. The performance of the tau algorithms, both offline and at the trigger level, is found to be stable with respect to the number of concurrent proton-proton interactions and has supported a variety of physics results using hadronically decaying tau leptons at ATLAS.
Published: 2015

45. ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider.

Author: Aad, G, Abbott, B, Abdallah, J, Abdinov, O, Aben, R, Abolins, M, AbouZeid, OS, 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, Alimonti, G, Alio, L, Alison, J, Alkire, SP, Allbrooke, BMM, Allport, PP, Aloisio, A, Alonso, A, Alonso, F, Alpigiani, C, Altheimer, A, 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, Amram, N, 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, Antos, J, Anulli, F, Aoki, M, Aperio Bella, L, 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, Arratia, M, Arslan, O, and Artamonov, A
Subjects: ATLAS Publications, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper reviews and extends searches for the direct pair production of the scalar supersymmetric partners of the top and bottom quarks in proton-proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20 [Formula: see text] of collisions at a centre-of-mass energy of [Formula: see text] TeV, although in some case an additional [Formula: see text] of collision data at [Formula: see text] TeV are used. New analyses are introduced to improve the sensitivity to specific regions of the model parameter space. Since no evidence of third-generation squarks is found, exclusion limits are derived by combining several analyses and are presented in both a simplified model framework, assuming simple decay chains, as well as within the context of more elaborate phenomenological supersymmetric models.
Published: 2015

46. Measurement of the inclusive 3-jet production differential cross section in proton-proton collisions at 7 TeV and determination of the strong coupling constant in the TeV range.

Author: Khachatryan, V, Sirunyan, AM, Tumasyan, A, Adam, W, Bergauer, T, Dragicevic, M, Erö, J, Fabjan, C, Friedl, M, Frühwirth, R, Ghete, VM, Hartl, C, Hörmann, N, Hrubec, J, Jeitler, M, Kiesenhofer, W, Knünz, V, Krammer, M, Krätschmer, I, Liko, D, Mikulec, I, Rabady, D, Rahbaran, B, Rohringer, H, Schöfbeck, R, Strauss, J, Taurok, A, Treberer-Treberspurg, W, Waltenberger, W, Wulz, C-E, Mossolov, V, Shumeiko, N, Suarez Gonzalez, J, Alderweireldt, S, Bansal, M, Bansal, S, Cornelis, T, De Wolf, EA, Janssen, X, Knutsson, A, Luyckx, S, Ochesanu, S, Rougny, R, Van De Klundert, M, Van Haevermaet, H, Van Mechelen, P, Van Remortel, N, Van Spilbeeck, A, Blekman, F, Blyweert, S, D'Hondt, J, Daci, N, Heracleous, N, Keaveney, J, Lowette, S, Maes, M, Olbrechts, A, Python, Q, Strom, D, Tavernier, S, Van Doninck, W, Van Mulders, P, Van Onsem, GP, Villella, I, Caillol, C, Clerbaux, B, De Lentdecker, G, Dobur, D, Favart, L, Gay, APR, Grebenyuk, A, Léonard, A, Mohammadi, A, Perniè, L, Reis, T, Seva, T, Thomas, L, Vander Velde, C, Vanlaer, P, Wang, J, Zenoni, F, Adler, V, Beernaert, K, Benucci, L, Cimmino, A, Costantini, S, Crucy, S, Dildick, S, Fagot, A, Garcia, G, Mccartin, J, Ocampo Rios, AA, Ryckbosch, D, Salva Diblen, S, Sigamani, M, Strobbe, N, Thyssen, F, Tytgat, M, Yazgan, E, and Zaganidis, N
Subjects: 3-jet mass, Alpha-S, CMS, Jets, PDF, Physics, QCD, Strong coupling constant, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a measurement of the inclusive 3-jet production differential cross section at a proton-proton centre-of-mass energy of 7 TeV using data corresponding to an integrated luminosity of 5[Formula: see text]collected with the CMS detector. The analysis is based on the three jets with the highest transverse momenta. The cross section is measured as a function of the invariant mass of the three jets in a range of 445-3270 GeV and in two bins of the maximum rapidity of the jets up to a value of 2. A comparison between the measurement and the prediction from perturbative QCD at next-to-leading order is performed. Within uncertainties, data and theory are in agreement. The sensitivity of the observable to the strong coupling constant [Formula: see text] is studied. A fit to all data points with 3-jet masses larger than 664 GeV gives a value of the strong coupling constant of [Formula: see text].
Published: 2015

47. Distributions of topological observables in inclusive three- and four-jet events in pp collisions at [Formula: see text][Formula: see text].

Author: Khachatryan, V, Sirunyan, AM, Tumasyan, A, Adam, W, Bergauer, T, Dragicevic, M, Erö, J, Friedl, M, Frühwirth, R, Ghete, VM, Hartl, C, Hörmann, N, Hrubec, J, Jeitler, M, Kiesenhofer, W, Knünz, V, Krammer, M, Krätschmer, I, Liko, D, Mikulec, I, Rabady, D, Rahbaran, B, Rohringer, H, Schöfbeck, R, Strauss, J, Treberer-Treberspurg, W, Waltenberger, W, Wulz, C-E, Mossolov, V, Shumeiko, N, Suarez Gonzalez, J, Alderweireldt, S, Bansal, S, Cornelis, T, De Wolf, EA, Janssen, X, Knutsson, A, Lauwers, J, Luyckx, S, Ochesanu, S, Rougny, R, Van De Klundert, M, Van Haevermaet, H, Van Mechelen, P, Van Remortel, N, Van Spilbeeck, A, Blekman, F, Blyweert, S, D'Hondt, J, Daci, N, Heracleous, N, Keaveney, J, Lowette, S, Maes, M, Olbrechts, A, Python, Q, Strom, D, Tavernier, S, Van Doninck, W, Van Mulders, P, Van Onsem, GP, Villella, I, Caillol, C, Clerbaux, B, De Lentdecker, G, Dobur, D, Favart, L, Gay, APR, Grebenyuk, A, Léonard, A, Mohammadi, A, Perniè, L, Randle-Conde, A, Reis, T, Seva, T, Thomas, L, Vander Velde, C, Vanlaer, P, Wang, J, Zenoni, F, Adler, V, Beernaert, K, Benucci, L, Cimmino, A, Costantini, S, Crucy, S, Dildick, S, Fagot, A, Garcia, G, Mccartin, J, Ocampo Rios, AA, Ryckbosch, D, Salva Diblen, S, Sigamani, M, Strobbe, N, Thyssen, F, Tytgat, M, Yazgan, E, Zaganidis, N, and Basegmez, S
Subjects: CMS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents distributions of topological observables in inclusive three- and four-jet events produced in pp collisions at a centre-of-mass energy of 7[Formula: see text] with a data sample collected by the CMS experiment corresponding to a luminosity of 5.1[Formula: see text]. The distributions are corrected for detector effects, and compared with several event generators based on two- and multi-parton matrix elements at leading order. Among the considered calculations, MadGraph interfaced with pythia6 displays the overall best agreement with data.
Published: 2015

48. Fastlim: a fast LHC limit calculator.

Author: Papucci, Michele, Sakurai, Kazuki, Weiler, Andreas, and Zeune, Lisa
Subjects: hep-ph, hep-ex, Nuclear & Particles Physics, Quantum Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics
Abstract: Fastlim is a tool to calculate conservative limits on extensions of the Standard Model from direct LHC searches without performing any Monte Carlo event generation. The program reconstructs the visible cross sections (cross sections after event selection cuts) from pre-calculated efficiency tables and cross section tables for simplified event topologies. As a proof of concept of the approach, we have implemented searches relevant for supersymmetric models with R-parity conservation. Fastlim takes the spectrum and coupling information of a given model point and provides, for each signal region of the implemented analyses, the visible cross sections normalised to the corresponding upper limit, reported by the experiments, as well as the [Formula: see text] value. To demonstrate the utility of the program we study the sensitivity of the recent ATLAS missing energy searches to the parameter space of natural SUSY models. The program structure allows the straightforward inclusion of external efficiency tables and can be generalised to R-parity violating scenarios and non-SUSY models. This paper serves as a self-contained user guide and indicates the conventions and approximations used.
Published: 2014

49. Muon reconstruction efficiency and momentum resolution of the ATLAS experiment in proton-proton collisions at [Formula: see text] TeV in 2010.

Author: ATLAS Collaboration, 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, Abulaiti, Y, Acharya, BS, Adamczyk, L, Adams, DL, Addy, TN, Adelman, J, Adomeit, S, Adye, T, Aefsky, S, Agatonovic-Jovin, T, 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, Alconada Verzini, MJ, 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, Amaral Coutinho, Y, 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, Anduaga, XS, Angelidakis, S, 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, and Arce, ATH
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents a study of the performance of the muon reconstruction in the analysis of proton-proton collisions at [Formula: see text] TeV at the LHC, recorded by the ATLAS detector in 2010. This performance is described in terms of reconstruction and isolation efficiencies and momentum resolutions for different classes of reconstructed muons. The results are obtained from an analysis of [Formula: see text] meson and [Formula: see text] boson decays to dimuons, reconstructed from a data sample corresponding to an integrated luminosity of 40 pb[Formula: see text]. The measured performance is compared to Monte Carlo predictions and deviations from the predicted performance are discussed.
Published: 2014

50. Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton-proton collision data.

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, Arik, M, and Armbruster, AJ
Subjects: ATLAS Collaboration, hep-ex, Nuclear & Particles Physics, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Quantum Physics
Abstract: This paper presents the performance of the ATLAS muon reconstruction during the LHC run with [Formula: see text] collisions at [Formula: see text]-8 TeV in 2011-2012, focusing mainly on data collected in 2012. Measurements of the reconstruction efficiency and of the momentum scale and resolution, based on large reference samples of [Formula: see text], [Formula: see text] and [Formula: see text] decays, are presented and compared to Monte Carlo simulations. Corrections to the simulation, to be used in physics analysis, are provided. Over most of the covered phase space (muon [Formula: see text] and [Formula: see text] GeV) the efficiency is above [Formula: see text] and is measured with per-mille precision. The momentum resolution ranges from [Formula: see text] at central rapidity and for transverse momentum [Formula: see text] GeV, to [Formula: see text] at large rapidity and [Formula: see text] GeV. The momentum scale is known with an uncertainty of [Formula: see text] to [Formula: see text] depending on rapidity. A method for the recovery of final state radiation from the muons is also presented.
Published: 2014

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