1. Quarkonia in heavy ion collisions @ LHC
heavy flavors & LHC
detector performances
selected physics channels

2. Heavy flavors: what is different @ the LHC
central AA
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 charmonia
statistical hadronization, kinetic recombination, DD annhililation
RHIC
LHC
hard gluon induced quarkonium breakup hep-ph/

3. (di)leptons: what is different @ the LHC
dimuons in ALICE, pt > 2 GeV/c
unlike-sign total
unlike-sign from bottom
unlike-sign from charm
like-sign from bottom
charm pure NLO
Z. Conesa del Valle
(2005)
 in ALICE
14TeV
S. Grigoryan (2004)
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

4. 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%) 5.5 TeV : 0.49*
N(bb pairs) in central (5%) 5.5 TeV : 4.56#
 N(b  J/) / N(direct J/) ~ 20% in 4 (22% in 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 , hep-ph/ , CEM, underpredicts CDF data by a factor 2
#from ALICE PPR VII, CERN/LHCC , uncertainty: a factor 2-3 (mQ, F, R, PDF)

5. using (2s) to unravel J/ suppression vs. regeneration
One physics case: on the relevance of measuring  in heavy ion collisions at the LHC
using (2s) to unravel J/ suppression vs. regeneration
J/ suppression & regeneration?
c suppression (J/ TD > 1.5 Tc)?
H. Satz, CERN Heavy Ion Forum, 09/06/05
enhanced suppression
enhanced regeneration
TLHC >> J/ TD ~ (2s) TD
C.-Y. Wong, PRC
W.M. Alberico et al., PRD
 regeneration is small
L. Grandchamp et al., hep-ph/
SPS
RHIC
LHC 30

6. M.Rosati Tuesday parallel II
Heavy ions @ the LHC
CMS: strong heavy ion program
D.d’Enterria Tuesday parallel II
ATLAS: heavy ion LOI (2004)
M.Rosati Tuesday parallel II
ALICE: the dedicated heavy ion experiment

7. ALICE (A Large Ion Collider Experiment)
TOF
DIPOLE MAGNET
HMPID
TRD
ACORDE
L3 MAGNET
PMD
FMD
ITS
MUON TRIGGER CHAMBERS
TPC
PHOS
MUON FILTER
ABSORBER
MUON TRACKING CHAMBERS

8. 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

9. LHC inner trackers expected performances
(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
ALICE: CERN/LHC , CERN/LHCC 99-13, ATLAS: EPJC 33 (2004) s1023, CMS: CMS NOTE 2006/031, 2001/008

10. Transverse momentum acceptance for quarkonia measurements
CMS J/
ALICE J/  e+e-
acceptance
|| < 2.4
barrel
ALICE can measure J/ down to 0 pt 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.!)
w/o trigger
with trigger
ALICE J/  µ+µ-
ALICE: PPRVII, CERN/LHCC , CMS: NOTE 2006/089

11. background level 1 = 2 HIJING evts with dN/d = 6000 @  = 0 each
 mass resolution (  100 M ~ 10 GeV is needed to separate the  sub-states)
CMS
dN/d = 2500
|| < 2.4
 ~ 90 MeV
CMS
no bkg
|| < 0.8
 ~ 54 MeV
ALICE electron dN/d = 6000
ATLAS
dN/d = 3000
|| < 2
 ~ 145 MeV
background level 1 = 2 HIJING evts with dN/d =  = 0 each
ALICE muon
warning:
≠ simulation frameworks & inputs
ongoing analyses
ALICE: PPRVII, CERN/LHCC , ATLAS: CERN/LHCC/ , CMS: NOTE 2006/089

12. Expected statistics in ALICE-muon
1 LHC year = 7 months pp (107s, 3·1030cm-2s-1) + 1 month AA (106s, 5·1026cm-2s-1)
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
4670
122
44.7
11.4
6.9
12.6
0.55
5.8
1.9
1.3
2081
209
195 86 62
full simulation including
realistic geometry
trigger efficiency
reconstruction efficiency
tracking efficiency
resolutions
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
ALICE PPR VII, CERN/LHCC , x-sections from CERN , hep-ph/ , with shadowing & feed-down, w/o nuclear absorption/suppression/regeneration…

13. From NA50’s (J/)/DY to ALICE’s /bbbar
EPJC 39 (2005) 335
NA50 17GeV
ALICE 5.5TeV
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
ALICE PPRVII, CERN/LHCC
dissociation temperatures: C.-Y. Wong, PRC & W.M. Alberico et al., PRD

14. ’/ ratio versus pt melting depends on
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
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
full & realistic simulation
error bars = 1 month of central PbPb (10%)
E. Dumonteil, PhD Thesis (2004), ALICE-INT

15. Using b decays to probe the QGP
a measurement of (J/)/(b) = (2)1% or ’/(J/) = is an evidence for full J/ suppression (& no regeneration!)
no need to disentangle prompt & secondary J/!
ALICE PPRVII, CERN/LHCC

16. Instead of a summary, what will happen next year
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…
first physics run!

18. BACKUP

19. 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

22. Combined 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