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Author ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A.
Title Measurement of the centrality dependence of J/psi yields and observation of Z production in lead-lead collisions with the ATLAS detector at the LHC Type Journal Article
Year 2011 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 697 Issue 4 Pages 294-312
Keywords ATLAS; LHC; Heavy ions; J/psi; Z boson; Centrality dependence
Abstract Using the ATLAS detector, a centrality-dependent suppression has been observed in the yield of J/psi mesons produced in the collisions of lead ions at the Large Hadron Collider. In a sample of minimum-bias lead-lead collisions at a nucleon-nucleon centre of mass energy root s(NN) = 2.76 TeV, corresponding to an integrated luminosity of about 6.7 μb(-1), J/psi mesons are reconstructed via their decays to mu(+)mu(-) pairs. The measured J/psi yield, normalized to the number of binary nucleon-nucleon collisions, is found to significantly decrease from peripheral to central collisions. The centrality dependence is found to be qualitatively similar to the trends observed at previous, lower energy experiments. The same sample is used to reconstruct Z bosons in the mu(+)mu(-) final state, and a total of 38 candidates are selected in the mass window of 66 to 116 GeV. The relative Z yields as a function of centrality are also presented, although no conclusion can be inferred about their scaling with the number of binary collisions, because of limited statistics. This analysis provides the first results on J/psi and Z production in lead-lead collisions at the LHC.
Address [Akdogan, T.; Arik, E.; Arik, M.; Dogan, O. B.; Istin, S.; Rador, T.] Bogazici Univ, Dept Phys, Fac Sci, TR-80815 Bebek, Turkey, Email: adas.publications@cern.ch
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes (up) ISI:000288300400006 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 543
Permanent link to this record
 

 
Author ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A.
Title Measurement of the production cross section for W-bosons in association with jets in pp collisions at root s=7 TeV with the ATLAS detector Type Journal Article
Year 2011 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 698 Issue 5 Pages 325-345
Keywords W-boson; Jets; ATLAS; LHC; Proton-proton; 7 TeV
Abstract This Letter reports on a first measurement of the inclusive W + jets cross section in proton-proton collisions at a centre-of-mass energy of 7 TeV at the LHC, with the ATLAS detector. Cross sections, in both the electron and muon decay modes of the W-boson, are presented as a function of jet multiplicity and of the transverse momentum of the leading and next-to-leading jets in the event. Measurements are also presented of the ratio of cross sections sigma (W + >= n)/sigma(W + >= n – 1) for inclusive jet multiplicities n = 1-4. The results, based on an integrated luminosity of 1.3 pb(-1), have been corrected for all known detector effects and are quoted in a limited and well-defined range of jet and lepton kinematics. The measured cross sections are compared to particle-level predictions based on perturbative QCD. Next-to-leading order calculations, studied here for n <= 2, are found in good agreement with the data. Leading-order multiparton event generators, normalized to the NNLO total cross section, describe the data well for all measured jet multiplicities.
Address [Aad, G.; Ahles, F.; Beckingham, M.; Bernhard, R.; Bitenc, U.; Bruneliere, R.; Buckley, A. G.; Caron, S.; Carpentieri, C.; Christov, A.; Dahlhoff, A.; Dietrich, J.; Eckert, S.; Fehling-Kaschek, M.; Flechl, M.; Glatzer, J.; Hartert, J.; Heldmann, M.; Herten, G.; Horner, S.; Jakobs, K.; Ketterer, C.; Koenig, S.; Kollefrath, M.; Kononov, A. I.; Kuehn, S.; Lai, S.; Landgraf, U.; Lohwasser, K.; Ludwig, I.; Ludwig, J.; Lumb, D.; Maassen, M.; Mahboubi, K.; Meinhardt, J.; Mohr, W.; Nilsen, H.; Parzefall, U.; Bueso, X. Portell; Rammensee, M.; Runge, K.; Rurikova, Z.; Schmidt, E.; Schumacher, M.; Siegert, F.; Stoerig, K.; Temming, K. K.; Thoma, S.; Tobias, J.; Tsiskaridze, V.; Venturi, M.; Vivarelli, I.; von Radziewski, H.; Warsinsky, M.; Weiser, C.; Werner, M.; Wiik, L. A. M.; Winkelmann, S.; Xie, S.; Zimmermann, S.] Univ Freiburg, Fak Math & Phys, D-79104 Freiburg, Germany, Email: atlas.publications@cern.ch
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes (up) ISI:000290185500001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 628
Permanent link to this record
 

 
Author ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A.
Title Search for squarks and gluinos using final states with jets and missing transverse momentum with the ATLAS detector in root s=7 TeV proton-proton collisions Type Journal Article
Year 2011 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 701 Issue 2 Pages 186-203
Keywords Supersymmetry; Squark; Gluino; Search; LHC; ATLAS
Abstract A search for squarks and gluinos in final states containing jets, missing transverse momentum and no electrons or muons is presented. The data were recorded by the ATLAS experiment in root s = 7 TeV proton-proton collisions at the Large Hadron Collider. No excess above the Standard Model background expectation was observed in 35 pb(-1) of analysed data. Gluino masses below 500 GeV are excluded at the 95% confidence level in simplified models containing only squarks of the first two generations, a gluino octet and a massless neutralino. The exclusion increases to 870 GeV for equal mass squarks and gluinos. In MSUGRA/CMSSM models with tan beta = 3, A(0) = 0 and μ> 0, squarks and gluinos of equal mass are excluded below 775 GeV. These are the most stringent limits to date.
Address [Aad, G; Ahles, F; Beckingham, M; Bernhard, R; Bitenc, U; Bruneliere, R; Caron, S; Carpentieri, C; Christov, A; Dahlhoff, A; Dietrich, J; Eckert, S; Fehling-Kaschek, M; Flechl, M; Glatzer, J; Hartert, J; Heldmann, M; Herten, G; Horner, S; Jakobs, K; Ketterer, C; Konig, S; Kollefrath, M; Kononov, AI; Kuehn, S; Lai, S; Landgraf, U; Lohwasser, K; Ludwig, I; Ludwig, J; Lumb, D; Mahboubi, K; Meinhardt, J; Mohr, W; Nilsen, H; Parzefall, U; Bueso, XP; Rammensee, M; Rave, TC; Runge, K; Rurikova, Z; Schmidt, E; Schumacher, M; Siegert, F; Stoerig, K; Sundermann, JE; Temming, KK; Thoma, S; Tobias, J; Tsiskaridze, V; Venturi, M; Vivarelli, I; von Radziewski, H; Warsinsky, M; Weiser, C; Werner, M; Wiik, LAM; Winkelmann, S; Xie, S; Zimmermann, S] Univ Freiburg, Fak Math & Phys, Freiburg, Germany
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000292993900005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ elepoucu @ Serial 755
Permanent link to this record
 

 
Author ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A.
Title Search for supersymmetry in pp collisions at sqrt(s)=7 TeV in final states with missing transverse momentum and b-jets Type Journal Article
Year 2011 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 701 Issue 4 Pages 398-416
Keywords Supersymmetry; ATLAS; LHC; Sbottom; Stop; Gluino
Abstract Results are presented of a search for supersymmetric particles in events with large missing transverse momentum and at least one heavy flavour jet candidate in root s = 7 TeV proton proton collisions. In a data sample corresponding to an integrated luminosity of 35 pb(-1) recorded by the ATLAS experiment at the Large Hadron Collider, no significant excess is observed with respect to the prediction for Standard Model processes. For R-parity conserving models in which sbottoms (stops) are the only squarks to appear in the gluino decay cascade, gluino masses below 590 GeV (520 GeV) are excluded at the 95% C.L. The results are also interpreted in an MSUGRA/CMSSM supersymmetry breaking scenario with tan beta = 40 and in an SO(10) model framework.
Address [Alam, MS; Ernst, J; Rojo, V] SUNY Albany, Albany, NY 12222 USA
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000292994100005 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 699
Permanent link to this record
 

 
Author Moles-Valls, R.
Title Alignment of the ATLAS Inner Detector with proton-proton collision data Type Journal Article
Year 2011 Publication Nuclear Instruments & Methods in Physics Research A Abbreviated Journal Nucl. Instrum. Methods Phys. Res. A
Volume 650 Issue 1 Pages 235-239
Keywords ATLAS; Inner detector; Tracking system; Alignment
Abstract ATLAS is a multipurpose experiment that records the products of the LHC collisions. In order to reconstruct the trajectories of the charged particles produced in these collisions. ATLAS has an internal tracking system made of silicon planar sensors (pixels and micro-strips) and drift-tube based detectors; both together, they constitute the ATLAS Inner Detector. The alignment of the ATLAS tracking system requires the determination of their almost 36,000 degrees-of-freedom (DOF) with high accuracy. Thus, the demanded precision for the alignment of the pixel and micro-strip sensors is below 10 μm. As alignment algorithms are based on the minimization of the track-hit residuals, a linear system with a large number of DOF has to be solved. The alignment results of the ATLAS tracker using data recorded during cosmic commissioning phases in 2008 and 2009 and the LHC start up run in 2009 will be presented. Moreover recent 7 TeV data collected during 2010 run have been used to study the detector performance. These studies reveal that the detector is aligned with a precision high enough to cope with the requirements.
Address [Moles-Valls, R] IFIC CSIC UV Valencia, Valencia, Spain, Email: Regina.Moles@ific.uv.es
Corporate Author Thesis
Publisher Elsevier Science Bv Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0168-9002 ISBN Medium
Area Expedition Conference
Notes (up) WOS:000295106500050 Approved no
Is ISI yes International Collaboration no
Call Number IFIC @ elepoucu @ Serial 767
Permanent link to this record