Readiness of the ATLAS liquid argon calorimeter for LHC collisions

European Physical Journal C 70:3 (2010) 723-753

Authors:

The ATLAS Collaboration, G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, H Abramowicz, H Abreu, BS Acharya, DL Adams, TN Addy, J Adelman, C Adorisio, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, H Ahmed, M Ahsan, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, A Aktas, MS Alam, MA Alam, J Albert, S Albrand, M Aleksa, IN Aleksandrov, F Alessandria, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, MG Alviggi, K Amako, C Amelung, VV Ammosov, A Amorim, G Amorós, N Amram, C Anastopoulos, T Andeen, CF Anders, KJ Anderson, A Andreazza, V Andrei, XS Anduaga, A Angerami, F Anghinolfi, N Anjos, A Antonaki, M Antonelli, S Antonelli, B Antunovic, F Anulli, S Aoun, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, S Arfaoui, JF Arguin, T Argyropoulos, E Arik, M Arik, AJ Armbruster, O Arnaez, C Arnault, A Artamonov, D Arutinov, M Asai, S Asai, R Asfandiyarov, S Ask, B Åsman, D Asner, L Asquith, K Assamagan

Abstract:

The ATLAS liquid argon calorimeter has been operating continuously since August 2006. At this time, only part of the calorimeter was readout, but since the beginning of 2008, all calorimeter cells have been connected to the ATLAS readout system in preparation for LHC collisions. This paper gives an overview of the liquid argon calorimeter performance measured in situ with random triggers, calibration data, cosmic muons, and LHC beam splash events. Results on the detector operation, timing performance, electronics noise, and gain stability are presented. High energy deposits from radiative cosmic muons and beam splash events allow to check the intrinsic constant term of the energy resolution. The uniformity of the electromagnetic barrel calorimeter response along η (averaged over Φ) is measured at the percent level using minimum ionizing cosmic muons. Finally, studies of electromagnetic showers from radiative muons have been used to cross-check the Monte Carlo simulation. The performance results obtained using the ATLAS readout, data acquisition, and reconstruction software indicate that the liquid argon calorimeter is well-prepared for collisions at the dawn of the LHC era. © 2010 CERN for the benefit of the ATLAS collaboration.

The ATLAS Inner Detector commissioning and calibration

European Physical Journal C 70:3 (2010) 787-821

Authors:

G Aad, B Abbott, J Abdallah, AA Abdelalim, A Abdesselam, O Abdinov, B Abi, M Abolins, H Abramowicz, H Abreu, BS Acharya, DL Adams, TN Addy, J Adelman, C Adorisio, P Adragna, T Adye, S Aefsky, JA Aguilar-Saavedra, M Aharrouche, SP Ahlen, F Ahles, A Ahmad, M Ahsan, G Aielli, T Akdogan, TPA Åkesson, G Akimoto, AV Akimov, A Aktas, MS Alam, MA Alam, S Albrand, M Aleksa, IN Aleksandrov, C Alexa, G Alexander, G Alexandre, T Alexopoulos, M Alhroob, M Aliev, G Alimonti, J Alison, M Aliyev, PP Allport, SE Allwood-Spiers, J Almond, A Aloisio, R Alon, A Alonso, MG Alviggi, K Amako, C Amelung, A Amorim, G Amorós, N Amram, C Anastopoulos, T Andeen, CF Anders, KJ Anderson, A Andreazza, V Andrei, XS Anduaga, A Angerami, F Anghinolfi, N Anjos, A Annovi, A Antonaki, M Antonelli, S Antonelli, J Antos, B Antunovic, F Anulli, S Aoun, G Arabidze, I Aracena, Y Arai, ATH Arce, JP Archambault, S Arfaoui, JF Arguin, T Argyropoulos, M Arik, AJ Armbruster, O Arnaez, C Arnault, A Artamonov, D Arutinov, M Asai, S Asai, R Asfandiyarov, S Ask, B Åsman, D Asner, L Asquith, K Assamagan, A Astvatsatourov, G Atoian, B Auerbach, K Augsten

Abstract:

The ATLAS Inner Detector is a composite tracking system consisting of silicon pixels, silicon strips and straw tubes in a 2 T magnetic field. Its installation was completed in August 2008 and the detector took part in data-taking with single LHC beams and cosmic rays. The initial detector operation, hardware commissioning and in-situ calibrations are described. Tracking performance has been measured with 7. 6 million cosmic-ray events, collected using a tracking trigger and reconstructed with modular pattern-recognition and fitting software. The intrinsic hit efficiency and tracking trigger efficiencies are close to 100%. Lorentz angle measurements for both electrons and holes, specific energy-loss calibration and transition radiation turn-on measurements have been performed. Different alignment techniques have been used to reconstruct the detector geometry. After the initial alignment, a transverse impact parameter resolution of 22. 1±0. 9 μm and a relative momentum resolution σp/p=(4. 83±0. 16)×10-4 GeV-1×pT have been measured for high momentum tracks. © 2010 CERN for the benefit of the ATLAS collaboration.

The T2K near detector data acquisition systems

Conference Record - 2010 17th IEEE-NPSS Real Time Conference, RT10 (2010)

Authors:

M Thorpe, C Angelsen, G Barr, C Metelko, T Nicholls, G Pearce, N West

Abstract:

T2K is a second generation long-baseline experiment in Japan, designed to perform precision studies of neutrino oscillations. A neutrino beam originating at the J-PARC facility is sampled by two near detectors, approximately 280m distant from the source and directed towards the Kamioka underground facility, 295km distant, where the Super-Kamiokande water Cerenkov detector is situated. Both the on-axis (INGRID) and off-axis (ND280) near detectors employ the MIDAS framework for their data acquisition systems. Events are selected via a flexible hardware trigger, which allows mixed operating modes incorporating beam spill, cosmic and calibration triggers. Data are acquired from the front-end electronics over optical gigabit Ethernet links by custom MIDAS front-end applications distributed over a cluster of Linux computers. Event fragments from all sub-detectors are merged and logged on a central backend processor and then copied to remote storage for longterm archival. The system is also designed to allow flexible partitioning of sub-detectors for standalone diagnostics and calibration. We present the design of the DAQ system and report on experience gathered during early operation of the near detectors. © 2010 IEEE.

Measurement of Neutrino-Induced Charged-Current Charged Pion Production Cross Sections on Mineral Oil at E$_{\nu}\sim 1~\textrm{GeV}$

(2010)

Authors:

AA Aguilar-Arevalo, CE Anderson, AO Bazarko, SJ Brice, BC Brown, L Bugel, J Cao, L Coney, JM Conrad, DC Cox, A Curioni, R Dharmapalan, Z Djurcic, DA Finley, BT Fleming, R Ford, FG Garcia, GT Garvey, J Grange, C Green, JA Green, TL Hart, E Hawker, R Imlay, RA Johnson, G Karagiorgi, P Kasper, T Katori, T Kobilarcik, I Kourbanis, S Koutsoliotas, EM Laird, SK Linden, JM Link, Y Liu, Y Liu, WC Louis, KBM Mahn, W Marsh, C Mauger, VT McGary, G McGregor, W Metcalf, PD Meyers, F Mills, GB Mills, J Monroe, CD Moore, J Mousseau, RH Nelson, P Nienaber, JA Nowak, B Osmanov, S Ouedraogo, RB Patterson, Z Pavlovic, D Perevalov, CC Polly, E Prebys, JL Raaf, H Ray, BP Roe, AD Russell, V Sandberg, R Schirato, D Schmitz, MH Shaevitz, FC Shoemaker, D Smith, M Soderberg, M Sorel, P Spentzouris, J Spitz, I Stancu, RJ Stefanski, M Sung, HA Tanaka, R Tayloe, M Tzanov, RG Van de Water, MO Wascko, DH White, MJ Wilking, HJ Yang, GP Zeller, ED Zimmerman

Updated search for the flavor-changing neutral-current decay D0→μ⊃+μ⊃- in pp̄ collisions at √s=1.96 TeV

Physical Review D - Particles, Fields, Gravitation and Cosmology 82:9 (2010)

Authors:

T Aaltonen, B Álvarez González, S Amerio, D Amidei, A Anastassov, A Annovi, J Antos, G Apollinari, JA Appel, A Apresyan, T Arisawa, A Artikov, J Asaadi, W Ashmanskas, B Auerbach, A Aurisano, F Azfar, W Badgett, A Barbaro-Galtieri, VE Barnes, BA Barnett, P Barria, P Bartos, M Bauce, G Bauer, F Bedeschi, D Beecher, S Behari, G Bellettini, J Bellinger, D Benjamin, A Beretvas, A Bhatti, M Binkley, D Bisello, I Bizjak, KR Bland, C Blocker, B Blumenfeld, A Bocci, A Bodek, D Bortoletto, J Boudreau, A Boveia, B Brau, L Brigliadori, A Brisuda, C Bromberg, E Brucken, M Bucciantonio, J Budagov, HS Budd, S Budd, K Burkett, G Busetto, P Bussey, A Buzatu, S Cabrera, C Calancha, S Camarda, M Campanelli, M Campbell, F Canelli, A Canepa, B Carls, D Carlsmith, R Carosi, S Carrillo, S Carron, B Casal, M Casarsa, A Castro, P Catastini, D Cauz, V Cavaliere, M Cavalli-Sforza, A Cerri, L Cerrito, YC Chen, M Chertok, G Chiarelli, G Chlachidze, F Chlebana, K Cho, D Chokheli, JP Chou, WH Chung, YS Chung, CI Ciobanu, MA Ciocci, A Clark, D Clark, G Compostella, ME Convery, J Conway, M Corbo, M Cordelli, CA Cox, DJ Cox, F Crescioli

Abstract:

We report on a search for the flavor-changing neutral-current decay D0→μ⊃+μ⊃- in pp̄ collisions at √s=1.96TeV using 360pb⊃-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. A displaced vertex trigger selects long-lived D0 candidates in the μ⊃+μ⊃-, π⊃+π⊃-, and K⊃-π⊃+ decay modes. We use the Cabibbo-favored D0→K⊃- π⊃+ channel to optimize the selection criteria in an unbiased manner, and the kinematically similar D0→π⊃+π⊃- channel for normalization. We set an upper limit on the branching fraction B(D0→μ⊃+μ⊃-)<2.1×10⊃-7(3.0×10⊃-7) at the 90% (95%) confidence level. © 2010 The American Physical Society.