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Observation of Spin Correlation in tt Events from pp Collisions at √s=7 TeV Using the ATLAS Detector

Aad, G. and Gray, H. M. and Marshall, Z. and Mateos, D. Lopez and Perez, K. (2012) Observation of Spin Correlation in tt Events from pp Collisions at √s=7 TeV Using the ATLAS Detector. Physical Review Letters, 108 (21). Art. No. 212001. ISSN 0031-9007. https://resolver.caltech.edu/CaltechAUTHORS:20120619-070934708

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Abstract

A measurement of spin correlation in tt production is reported using data collected with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 2.1  fb^(-1). Candidate events are selected in the dilepton topology with large missing transverse energy and at least two jets. The difference in azimuthal angle between the two charged leptons in the laboratory frame is used to extract the correlation between the top and antitop quark spins. In the helicity basis the measured degree of correlation corresponds to A_(helicity)=0.40_(-0.08)+^(0.09), in agreement with the next-to-leading-order standard model prediction. The hypothesis of zero spin correlation is excluded at 5.1 standard deviations.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1103/PhysRevLett.108.212001 DOIUNSPECIFIED
http://prl.aps.org/abstract/PRL/v108/i21/e212001PublisherUNSPECIFIED
http://link.aps.org/doi/10.1103/PhysRevLett.108.212001PublisherUNSPECIFIED
Additional Information:© 2012 CERN, for the ATLAS Collaboration. Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Received 19 March 2012; published 24 May 2012. We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhl, Armenia; ARC, Australia; BMWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC, and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST, and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR, and VSC CR, Czech Republic; DNRF, DNSRC, and Lundbeck Foundation, Denmark; EPLANET and ERC, European Union; IN2P3-CNRS, CEA-DSM/IRFU, France; GNAS, Georgia; BMBF, DFG, HGF, MPG, and AvH Foundation, Germany; GSRT, Greece; ISF, MINERVA, GIF, DIP, and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, The Netherlands; RCN, Norway; MNiSW, Poland; GRICES and FCT, Portugal; MERYS (MECTS), Romania; MES of Russia and ROSATOM, Russian Federation; JINR; MSTD, Serbia; MSSR, Slovakia; ARRS and MVZT, Slovenia; DST/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SER, SNSF and Cantons of Bern and Geneva, Switzerland; NSC, Taiwan; TAEK, Turkey; STFC, the Royal Society and Leverhulme Trust, United Kingdom; DOE and NSF, United States of America. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular, from CERN and the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CCIN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (U.K.) and BNL (U.S.) and in the Tier-2 facilities worldwide.
Funders:
Funding AgencyGrant Number
ANPCyT (Argentina)UNSPECIFIED
YerPhl (Armenia)UNSPECIFIED
ARC (Australia)UNSPECIFIED
BMWF (Austria)UNSPECIFIED
ANAS (Azerbaijan)UNSPECIFIED
SSTC (Belarus)UNSPECIFIED
CNPq and FAPESP (Brazil)UNSPECIFIED
NSERC (Canada)UNSPECIFIED
NRC and CFI (Canada)UNSPECIFIED
CERNUNSPECIFIED
CONICYT (Chile)UNSPECIFIED
CAS (China)UNSPECIFIED
MOST and NSFC (China)UNSPECIFIED
COLCIENCIAS (Colombia)UNSPECIFIED
MSMT CR (Czech Republic)UNSPECIFIED
MPO CR and VSC CR (Czech Republic)UNSPECIFIED
DNRF (Denmark)UNSPECIFIED
DNSRC and Lundbeck Foundation (Denmark)UNSPECIFIED
EPLANET and ERCUNSPECIFIED
European UnionUNSPECIFIED
IN2P3-CNRS (France)UNSPECIFIED
CEA-DSM/IRFU (France)UNSPECIFIED
GNAS (Georgia)UNSPECIFIED
BMBF (Germany)UNSPECIFIED
DFG (Germany)UNSPECIFIED
HGF (Germany)UNSPECIFIED
MPG and AvH Foundation (Germany)UNSPECIFIED
GSRT (Greece)UNSPECIFIED
ISF (Israel)UNSPECIFIED
MINERVA (Israel)UNSPECIFIED
GIF (Israel)UNSPECIFIED
DIP and Benoziyo Center (Israel)UNSPECIFIED
INFN (Italy)UNSPECIFIED
MEXT and JSPS (Japan)UNSPECIFIED
CNRST (Morocco)UNSPECIFIED
FOM and NWO (The Netherlands)UNSPECIFIED
RCN (Norway)UNSPECIFIED
MNiSW (Poland)UNSPECIFIED
GRICES and FCT (Portugal)UNSPECIFIED
MERYS (MECTS) (Romania)UNSPECIFIED
MES of Russia and ROSATOMUNSPECIFIED
JINRUNSPECIFIED
MSTD (Serbia)UNSPECIFIED
MSSR (Slovakia)UNSPECIFIED
ARRS and MVZT (Slovenia)UNSPECIFIED
DST/NRF (South Africa)UNSPECIFIED
MICINN (Spain)UNSPECIFIED
SRC and Wallenberg Foundation (Sweden)UNSPECIFIED
SER (Switzerland)UNSPECIFIED
SNSF and Cantons of Bern in Geneva (Switzerland)UNSPECIFIED
NSC (Taiwan)UNSPECIFIED
TAEK (Turkey)UNSPECIFIED
STFC (United Kingdom)UNSPECIFIED
Royal Society and Leverhulme Trust (United Kingdom)UNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
NSFUNSPECIFIED
Issue or Number:21
Classification Code:PACS: 14.65.Ha, 12.38.Qk, 13.85.Qk
Record Number:CaltechAUTHORS:20120619-070934708
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120619-070934708
Official Citation:Observation of Spin Correlation in tt̅ Events from pp Collisions at √s=7  TeV Using the ATLAS Detector G. Aad et al. (ATLAS Collaboration) Published 24 May 2012 (19 pages) 212001
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:31941
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:19 Jun 2012 14:40
Last Modified:03 Oct 2019 03:56

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