quarkonia in heavy ion collisions @ lhc
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Philippe.Crochet@clermont.in2p3.fr
• heavy flavors & heavy flavors & (di)leptons @ LHC(di)leptons @ LHC
• detector performancesdetector performances
• selected physics channelsselected physics channelsPhilippe.Crochet@clermont.in2p3.fr
Philippe.Crochet@clermont.in2p3.fr
Heavy flavors: what is different @ the LHC
• large primary production• melting of (1S) by color screening• none of the primary J/ survives the (PbPb)QGP• a lot of charmonia from b hadron decay• large secondary production of charmoniastatistical hadronization, kinetic recombination, DD annhililation
central AA
RHICLHC
hard gluon induced quarkonium breakup
hep-ph/0311048
Philippe.Crochet@clermont.in2p3.fr
Philippe.Crochet@clermont.in2p3.fr
dimuons in ALICE, pt > 2 GeV/c
unlike-sign totalunlike-sign from bottomunlike-sign from charm like-sign from bottom
S. Grigoryan (2004)
(di)leptons: what is different @ the LHC
Z. Conesa del Valle(2005)
in ALICE
pp @ 14TeV
charm pure NLO
Philippe.Crochet@clermont.in2p3.fr
• large & complex combinatorial background
• dileptons from b decay dominate the spectrum below & J/• large yield of secondary J/ from b decay
• dileptons from b decay have different origin at low & high mass
• sizeable yield of like-sign correlated dileptons from b decay
• W stick out from single lepton spectra with large statistics
Philippe.Crochet@clermont.in2p3.fr
J/ from b decay in central PbPb @ 5.5 TeV
Philippe.Crochet@clermont.in2p3.fr
• b J/ (1S) anything : 1.16 0.10% (PDG)
• N(direct J/) in central (5%) PbPb @ 5.5 TeV : 0.49*
• N(bb pairs) in central (5%) PbPb @ 5.5 TeV : 4.56#
N(b J/) / N(direct J/) ~ 20% in 4 (22% in pp @ 14 TeV)
(with shadowing & feed-down, w/o nuclear absorption, suppression, regeneration…)
• this is a lot!
• no obvious way to disentangle prompt & secondary J/ from pt dist. (only 2nd vertexing or b measurement can help)
*from CERN-2004-009, hep-ph/0311048, CEM, underpredicts CDF data by a factor 2
#from ALICE PPR VII, CERN/LHCC 2005-030, uncertainty: a factor 2-3 (mQ, F, R, PDF)
Philippe.Crochet@clermont.in2p3.fr
• J/ suppression & regeneration?
• c suppression (J/ TD > 1.5 Tc)?
H. Satz, CERN Heavy Ion Forum, 09/06/05
One physics case: on the relevance of measuring in heavy ion collisions at the LHC
using (2s) to unravel J/ suppression vs. regeneration
SPSRHICLHC
30
enhanced suppression
enhanced regeneration
• TLHC >> J/ TD ~ (2s) TD C.-Y. Wong, PRC 72 034906
W.M. Alberico et al., PRD 72 114011
• regeneration is smallL. Grandchamp et al., hep-ph/0507314
Philippe.Crochet@clermont.in2p3.fr
Heavy ions @ the LHC
CMS: strong heavy ion program
ALICE: the dedicated heavy ion experiment
D.d’Enterria Tuesday parallel II
ATLAS: heavy ion LOI (2004)
M.Rosati Tuesday parallel II
Philippe.Crochet@clermont.in2p3.fr
ALICE (A Large Ion Collider Experiment)
ITS
TPC
FMD
PHOSABSORBER
MUON TRACKING CHAMBERS
MUON FILTER
DIPOLE MAGNETTOFTRDHMPID
L3 MAGNET
PMD
MUON TRIGGER CHAMBERS
ACORDE
Philippe.Crochet@clermont.in2p3.fr
How LHC detectors measure quarkonia
• nice complementarity between the 3 experiments
• ATLAS & CMS acceptance is large in & limited to high pt
• ALICE acceptance covers low pt & high • ATLAS, CMS & ALICE-electron have inner tracking
Philippe.Crochet@clermont.in2p3.fr
LHC inner trackers expected performances
ALICE: CERN/LHC 2005-030, CERN/LHCC 99-13, ATLAS: EPJC 33 (2004) s1023, CMS: CMS NOTE 2006/031, 2001/008
(d0) < 50 µm for pt > 1.5/2/3 GeV/c in ALICE/CMS/ATLAS
• disentangle primary & secondary J/
• measure inclusive b cross-section
• probe b quark in-medium energy loss
Philippe.Crochet@clermont.in2p3.fr
Transverse momentum acceptance for quarkonia measurements
• ALICE can measure J/ down to 0 pt (unique @ LHC)
• ATLAS acceptance similar to CMS acceptance for J/
in central barrel
• ALICE, ATLAS & CMS can measure down to 0 pt
note: ≠ trigger & reconstruction efficiencies
(expected statistics doesn’t scale with geo. acc.!)ALICE J/ µ+µ-
ALICE J/ e+e-
ALICE: PPRVII, CERN/LHCC 2005-030, CMS: NOTE 2006/089
acce
pta
nce
CMS J/
|| < 2.4
barrel
w/o trigger
with trigger
Philippe.Crochet@clermont.in2p3.fr
mass resolution( 100 MeV @ M ~ 10 GeV is needed to separate the sub-states)
warning:
• ≠ simulation frameworks & inputs
• ongoing analyses
ALICE electron dN/d = 6000
background level 1 = 2 HIJING evts with dN/d = 6000 @ = 0 each
ALICE muon
CMSdN/d = 2500
|| < 2.4 ~ 90 MeV
ALICE: PPRVII, CERN/LHCC 2005-030, ATLAS: CERN/LHCC/2004-009, CMS: NOTE 2006/089
CMSno bkg|| < 0.8
~ 54 MeV
ATLASdN/d = 3000
|| < 2 ~ 145 MeV
Philippe.Crochet@clermont.in2p3.fr
from PbPb MB to pp, a factor ~ 10 more stat.
• J/: large stat., good significance
• ’: small S/B
• : good stat., S/B > 1, good significance
• ’: good stat., S/B > 1, good significance
• ’’: low statistics
Expected statistics in ALICE-muon
J/ ’ ’ ’’
PbPb MB
5.5 TeV
S (103) 681.4 18.92 6.33 1.8 1.02
S/B 0.33 0.02 2.46 1.03 0.74
S/S+B 413 19.53 67.14 30.19 20.85
pp
14 TeV
S (103) 4670 122 44.7 11.4 6.9
S/B 12.6 0.55 5.8 1.9 1.3
S/S+B 2081 209 195 86 62
ALICE PPR VII, CERN/LHCC 2005-030, x-sections from CERN-2004-009, hep-ph/0311048, with shadowing & feed-down, w/o nuclear absorption/suppression/regeneration…
full simulation including
• realistic geometry
• trigger efficiency
• reconstruction efficiency
• tracking efficiency
• resolutions
1 LHC year = 7 months pp (107s, 3·1030cm-2s-1) + 1 month AA (106s, 5·1026cm-2s-1)
Philippe.Crochet@clermont.in2p3.fr
From NA50’s (J/)/DY to ALICE’s /bbbar
• statistics : one month PbPb• (b) extracted à la UA1, CDF, D0• statistics of the reference is in
5<M<20GeV ~5 times larger than
that of the probe• systematic errors underway
EPJC 39 (2005) 335
NA50 PbPb @ 17GeV
ALICE PbPb @ 5.5TeV
ALICE PPRVII, CERN/LHCC 2005-030dissociation temperatures: C.-Y. Wong, PRC 72 034906 & W.M. Alberico et al., PRD 72
114011
Philippe.Crochet@clermont.in2p3.fr
’/ ratio versus pt
E. Dumonteil, PhD Thesis (2004), ALICE-INT-2005-002
• melting depends on
• resonance formation time, dissociation temp. & pt
• QGP temp., lifetime & size
• ratio is flat in ppbar (CDF)
• any deviation from the pp (pA) value is a clear evidence for the QGP (nuclear effects cancel-out)
• the pt dependence of the ratio is sensitive to the characteristics of the QGP
J.P. Blaizot & J.Y. Ollitrault, Phys. Lett. B 199(1987)499; F. Karsch & H. Satz, Z. Phys. C 51(1991)209; J.F. Gunion & R. Vogt, Nucl. Phys. B 492(1997)301
• full & realistic simulation
• error bars = 1 month of central PbPb (10%)
Philippe.Crochet@clermont.in2p3.fr
Using b decays to probe the QGP
a measurement of (J/)/(b) = (2)1% or ’/(J/) =
0.0625 is an evidence for full J/ suppression (& no
regeneration!)
no need to disentangle prompt & secondary J/!ALICE PPRVII, CERN/LHCC 2005-030
Philippe.Crochet@clermont.in2p3.fr
Instead of a summary, what will happen next year
first physics run!
2008
Jan.Aug. Sept. Oct. Nov. Dec. Feb. Mar. Apr. May Jun. July
2007
10 weeks pp
machine closure set-up, injection
shut-down pp high L, 1st PbPb…
Philippe.Crochet@clermont.in2p3.fr
Philippe.Crochet@clermont.in2p3.fr
Philippe.Crochet@clermont.in2p3.fr
BACKUP
Philippe.Crochet@clermont.in2p3.fr
Heavy ion (ALICE) data taking scenario
one LHC year = 7 months pp (107s) + 1 month AA (106s), starts in 2007
• 5 first years:
• regular pp runs at 14 TeV: commissioning, reference, dedicated pp physics
• first PbPb run at low luminosity: global observables, large x-sections
• 2 PbPb runs at high luminosity (Lint = 0.5nb-1/year): small x-sections
• 1 pA run: structure functions, hadronic reference
• 1 light ion run: energy density dependence
• later (different options depending on the first results):
• pp (or pp-like) at 5.5 TeV
• other light or intermediate-mass systems
• other systems p-likeA & Ap-like
• PbPb at low energy
• PbPb at 5.5 TeV & high luminosity
ALICE collaboration, J. Phys. G 30 (2004) 1517
Philippe.Crochet@clermont.in2p3.fr
Philippe.Crochet@clermont.in2p3.fr
2222
Combined momentum resolutionCombined momentum resolution
at low momentum dominated by
- ionization-loss fluctuations- multiple scattering
at high momentum determined by
- point measurement precision- alignment & calibration (assumed ideal here) resolution ~ 7% at 100 GeV/c
excellent performance in hard region!
F. Antinori, 06/20/05
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