Observation of Spin Correlation in tt Events from pp Collisions at √s=7 TeV Using the ATLAS Detector
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.
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.Attached Files
Published - Aad2012p18509Phys_Rev_Lett.pdf
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Additional details
- Eprint ID
- 31941
- Resolver ID
- CaltechAUTHORS:20120619-070934708
- ANPCyT (Argentina)
- YerPhl (Armenia)
- ARC (Australia)
- BMWF (Austria)
- ANAS (Azerbaijan)
- SSTC (Belarus)
- CNPq and FAPESP (Brazil)
- NSERC (Canada)
- NRC and CFI (Canada)
- CERN
- CONICYT (Chile)
- CAS (China)
- MOST and NSFC (China)
- COLCIENCIAS (Colombia)
- MSMT CR (Czech Republic)
- MPO CR and VSC CR (Czech Republic)
- DNRF (Denmark)
- DNSRC and Lundbeck Foundation (Denmark)
- EPLANET and ERC
- European Union
- IN2P3-CNRS (France)
- CEA-DSM/IRFU (France)
- GNAS (Georgia)
- BMBF (Germany)
- DFG (Germany)
- HGF (Germany)
- MPG and AvH Foundation (Germany)
- GSRT (Greece)
- ISF (Israel)
- MINERVA (Israel)
- GIF (Israel)
- 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
- JINR
- MSTD (Serbia)
- MSSR (Slovakia)
- ARRS and MVZT (Slovenia)
- DST/NRF (South Africa)
- MICINN (Spain)
- SRC and Wallenberg Foundation (Sweden)
- SER (Switzerland)
- SNSF and Cantons of Bern in Geneva (Switzerland)
- NSC (Taiwan)
- TAEK (Turkey)
- STFC (United Kingdom)
- Royal Society and Leverhulme Trust (United Kingdom)
- Department of Energy (DOE)
- NSF
- Created
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2012-06-19Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field