Quarkonia in heavy ion collisions @ LHC
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[email protected] 2p3.fr • heavy flavors & heavy flavors & (di)leptons @ LHC (di)leptons @ LHC • detector performances detector performances • selected physics selected physics channels channels [email protected] 2p3.fr
description
Quarkonia in heavy ion collisions @ LHC. heavy flavors & (di)leptons @ LHC detector performances selected physics channels. [email protected]. central AA. hard gluon induced quarkonium breakup hep-ph/0311048. RHIC. LHC. Heavy flavors: what is different @ the LHC. - PowerPoint PPT Presentation
Transcript of Quarkonia in heavy ion collisions @ LHC
• heavy flavors & heavy flavors & (di)leptons @ LHC(di)leptons @ LHC
• detector performancesdetector performances
• selected physics channelsselected physics [email protected]
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
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
• 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
J/ from b decay in central PbPb @ 5.5 TeV
• 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)
• 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
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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
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
ALICE (A Large Ion Collider Experiment)
ITS
TPC
FMD
PHOSABSORBER
MUON TRACKING CHAMBERS
MUON FILTER
DIPOLE MAGNETTOFTRDHMPID
L3 MAGNET
PMD
MUON TRIGGER CHAMBERS
ACORDE
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
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
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
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
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)
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
’/ 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%)
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
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…
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
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
