First results from ALICE Christine Nattrass University of Tennessee at Knoxville 2 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 Exploring QCD at high temperatures F. Karsch, et al. Nucl. Phys. B605 (2001) 579 Confined - fewer degrees of freedom Deconfined - more degrees of freedom /T 4 ~ # degrees of freedom T C ~ 175 8 MeV C ~ GeV/fm 3 2 Quark-gluon plasma Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, Simple expectations for heavy ion physics at the LHC SPSRHICLHC s NN (GeV) x dN ch /d~700~1200~ x T/T c Hotter (GeV/fm 3 ) Denser QGP (fm/c)222-4>10Longer lived 3 4 Size: 16 x 26 meters Weight: 10,000 tons Detectors: 18 5 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 Pb+Pb collisions Anticipated tracks in || Data MC 5 N ch >20 N ch >15 variable/tuneD6T Perugia0CSCPHOJET dN ch /d-20%-17%+3%-2% N ch N ch >10N ch >5N ch >15N ch >10 pTpT p T > 4 GeV/cp T > 1 GeV/c p T > 1 GeV/c K 0 S, , ` 34 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 K 0 S ratio at 900 GeV | | < 1 Very good agreement between STAR (200 GeV) and ALICE (900 GeV) Very different from CDF (630/1800) and UA1 (630) for p T > 1.5 GeV - UA1(630) and CDF(630) dont agree either Different triggers, acceptance, feed-down correction? 21 35 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 More to come... 7 TeV < 2% of statistics at 7 TeV 7 TeV 22 36 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 Bose-Einstein correlations QM enhancement of identical Bosons at small momentum difference: E nhancement of e.g. like-sign pions at low momentum difference q inv =|p 1 -p 2 | M easure the space-time evolution of the dense matter formed in heavy-ion collisions. I nterpretation for small systems (p+p, e + +e - ) is less obvious... Pb+Au p+p radius ~/width 23 37 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 Bose-Einstein correlations QM enhancement of identical Bosons at small momentum difference: E nhancement of e.g. like-sign pions at low momentum difference q inv=|p 1 -p 2 | M easure the space-time evolution of the dense matter formed in heavy-ion collisions. I nterpretation for small systems (p+p, e + +e - ) is less obvious... Pb+Au p+p radius ~/width Source radius vs N ch PRD: Vol. 82 (2010) ource radius 23 38 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 D 0 and D + dN/dp t - Most of the cross section at low p T - Shape at low p T very uncertain MB events => measure below 1 GeV (PID important at low p T !) 24 39 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 J/ production at 7 TeV Measurement of J/ over wide pseudorapidity range Rapidity spectra Transverse-momentum spectra J/ e + e - |y| < 1 J/ , y = 2.54.0 25 40 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 J/ production at 7 TeV (ICHEP 2010) very good agreement with LHCb pt spectra and cross section cross-section measurement in centralforward regions match 26 41 Christine Nattrass (UTK), US LHC User's Meeting, Oct. 29, 2010 Electromagnetic calorimeter EMCal: -0.7