for the ALICE collaboration University of Tennessee at Knoxville Results from ALICE Christine Nattrass for the ALICE collaboration University of Tennessee at Knoxville

Exploring QCD at high temperatures Quark-gluon plasma Deconfined - more degrees of freedom TC ~ 175 ±8 MeV →εC ~ 0.3 -1 GeV/fm3 Confined - fewer degrees of freedom F. Karsch, et al. Nucl. Phys. B605 (2001) 579 ε/T4~ # degrees of freedom 2

The phase transition in the laboratory

CMS LHCb 8.6 km 2.2 km ATLAS LHCf ALICE

CMS LHCb 8.6 km 2.2 km ATLAS LHCf ALICE

ALICE ~1000 members ~30 countries ~100 institutes 6 Oct 2008 Split J. Schukraft

Size: 16 x 26 meters Weight: 10,000 tons Detectors: 18 7

Trigger detectors: When do we have a collision? Size: 16 x 26 meters Weight: 10,000 tons Detectors: 18 Trigger detectors: When do we have a collision? 8

Trigger detectors: When do we have a collision? Size: 16 x 26 meters Weight: 10,000 tons Detectors: 18 Trigger detectors: When do we have a collision? Tracking detectors: Where did the particle go? 9

Trigger detectors: When do we have a collision? Size: 16 x 26 meters Weight: 10,000 tons Detectors: 18 Trigger detectors: When do we have a collision? Tracking detectors: Where did the particle go? Identification detectors: What kind of particle is it? 10

Trigger detectors: When do we have a collision? Size: 16 x 26 meters Weight: 10,000 tons Detectors: 18 Trigger detectors: When do we have a collision? Tracking detectors: Where did the particle go? Identification detectors: What kind of particle is it? Calorimeters: How much energy does the particle have? 11

p+p collisions

Pb+Pb collisions

Bulk properties Christine Nattrass (UTK), Southeastern Section of the APS, October 21, 2011 14

Centrality dependence of dNch/dη PRL 106, 032301 (2011) RHIC data scaled by 2.1 PHENIX PRC 71, 034908 (2005) dNch/dη = Number of charged tracks per unit pseudorapidity η = pseudorapidity = - ln[tan(θ/2)]

Centrality dependence of dNch/dη RHIC data scaled by 2.1 PRL 106, 032301 (2011) PHENIX PRC 71, 034908 (2005) dNch/dη = Number of charged tracks per unit pseudorapidity η = pseudorapidity = - ln[tan(θ/2)] Npart = number of participating nucleons

Transverse Energy (GeV) EThad from charged hadrons directly measured by the tracking detectors ftotal from MC to convert into total ET From RHIC to LHC ~2.5 increase dET/dh/ (0.5*Npart) Energy density (Bjorken) et ~ 16 GeV/(fm2c) RHIC: et =5.4±0.6 GeV/(fm2c) PRC71:034908 (2005) PRC70:054907 (2004) Centrality dependence similar to RHIC (PHENIX)

√sNN dependence dET/dh/(0.5*Npart) ~ 9 in 0-5% dNch/dη/(0.5*Npart) ~ 8 ~5% increase of Npart (353 → 383) → 2.7 x RHIC (consistent with 20% increase of <pT>) dNch/dη/(0.5*Npart) ~ 8 2.1 x RHIC 1.9 x pp (NSD) at 2.36 TeV growth with √s faster in AA than pp Grows faster than simple logarithmic scaling extrapolated from lower energy PRL105, 252301 (2010) PRC71:034908,2005 √sNN = Center of mass energy per nucleon

Probes of the Quark Gluon Plasma Christine Nattrass (UTK), Southeastern Section of the APS, October 21, 2011 19

Probes of the Quark Gluon Plasma Medium Want a probe which traveled through the collision

Probes of the Quark Gluon Plasma nucleus Want a probe which traveled through the collision QGP is short lived → need a probe created in the collision

Probes of the Quark Gluon Plasma nucleus Want a probe which traveled through the collision QGP is short lived → need a probe created in the collision We expect the medium to be dense → absorb probe

Single particles Measure spectra of hadrons and compare to those in p+p collisions or peripheral A+A collisions If high-pT hadrons are suppressed, this is evidence of jet quenching Assumption: sufficiently high-pT hadrons mostly come from jets Unmodified spectra: 𝑅 𝐴𝐴 = 1/ 𝑁 𝑒𝑣𝑡 𝐴𝐴 𝑑 2 𝑁 𝑐ℎ 𝐴𝐴 /𝑑η 𝑑𝑝 𝑇 〈 𝑁 𝑐𝑜𝑙𝑙 〉 1/ 𝑁 𝑒𝑣𝑡 𝑝𝑝 𝑑 2 𝑁 𝑐ℎ 𝑝𝑝 /𝑑η 𝑑𝑝 𝑇

Nuclear modification factor (RAA) Unidentified hadrons- π,K,p 𝑅 𝐴𝐴 = 1/ 𝑁 𝑒𝑣𝑡 𝐴𝐴 𝑑 2 𝑁 𝑐ℎ 𝐴𝐴 /𝑑η 𝑑𝑝 𝑇 〈 𝑁 𝑐𝑜𝑙𝑙 〉 1/ 𝑁 𝑒𝑣𝑡 𝑝𝑝 𝑑 2 𝑁 𝑐ℎ 𝑝𝑝 /𝑑η 𝑑𝑝 𝑇

Nuclear modification factor (RAA) 𝑅 𝐴𝐴 = 1/ 𝑁 𝑒𝑣𝑡 𝐴𝐴 𝑑 2 𝑁 𝑐ℎ 𝐴𝐴 /𝑑η 𝑑𝑝 𝑇 〈 𝑁 𝑐𝑜𝑙𝑙 〉 1/ 𝑁 𝑒𝑣𝑡 𝑝𝑝 𝑑 2 𝑁 𝑐ℎ 𝑝𝑝 /𝑑η 𝑑𝑝 𝑇

Nuclear modification factor (RAA) K0S K± ~1116 MeV/c2 ~494 MeV/c2 ~140 MeV/c2 K0S π+ π- ~8.6 cm 𝑅 𝐴𝐴 = 1/ 𝑁 𝑒𝑣𝑡 𝐴𝐴 𝑑 2 𝑁 𝑐ℎ 𝐴𝐴 /𝑑η 𝑑𝑝 𝑇 〈 𝑁 𝑐𝑜𝑙𝑙 〉 1/ 𝑁 𝑒𝑣𝑡 𝑝𝑝 𝑑 2 𝑁 𝑐ℎ 𝑝𝑝 /𝑑η 𝑑𝑝 𝑇

Baryon anomaly: Λ/K0S

Baryon anomaly: Λ/K0S Recombination Ann.Rev.Nucl.Part.Sci.58:177-205,2008

Charm nuclear modification factor D meson ~1865 MeV/c2 D0 π+ K- ~123 μm D+ π+ K- 312 μm 𝑅 𝐴𝐴 = 1/ 𝑁 𝑒𝑣𝑡 𝐴𝐴 𝑑 2 𝑁 𝑐ℎ 𝐴𝐴 /𝑑η 𝑑𝑝 𝑇 〈 𝑁 𝑐𝑜𝑙𝑙 〉 1/ 𝑁 𝑒𝑣𝑡 𝑝𝑝 𝑑 2 𝑁 𝑐ℎ 𝑝𝑝 /𝑑η 𝑑𝑝 𝑇

Conclusions Charged particle production and transverse energy follow same trends as seen at RHIC Energy higher than experimental extrapolation, lower than many models High pT particle production suppressed to ~0.15 of what we would expect from scaling p+p collisions → hot, dense medium produced Significant suppression observed even for heavy quarks

Backup slides

Non-photonic electrons Beauty + Charm pQCD Beauty Electrons pp

Charm cross section pp