Quarkonia: experimental possibilities. Denis Jouan Institut de Physique Nucléaire Orsay. International Workshop on the Physics of the Quark-Gluon Plasma Ecole Polytechnique, Palaiseau, France September 4-7, 2001. - PowerPoint PPT Presentation
Quarkonia: experimental possibilities • In the next 10 years two major worldwide facilities, RHIC and LHC, will allow the study of heavy ion collisions at increased energies. • Quarkonia are specific probe of the deconfinement, in this talk I try to summarize the main characteristics of the data that will be produced in the experiment measuring lepton pairs: NA60, PHENIX, CMS and ALICE. • Not all number are official ones. they could be personal extrapolation Denis Jouan Institut de Physique Nucléaire Orsay International Workshop on the Physics of the Quark-Gluon Plasma Ecole Polytechnique, Palaiseau, France September 4-7, 2001
Transcript
Quarkonia: experimental possibilities
• In the next 10 years two major worldwide facilities, RHIC and LHC, will allow the study of heavy ion collisions at increased energies.
• Quarkonia are specific probe of the deconfinement, in this talk I try to summarize the main characteristics of the data that will be produced in the experiment measuring lepton pairs: NA60, PHENIX, CMS and ALICE.
• Not all number are official ones. they could be personal extrapolation
Denis Jouan Institut de Physique Nucléaire
Orsay International Workshop on the
Physics of the Quark-Gluon PlasmaEcole Polytechnique, Palaiseau, France
September 4-7, 2001
Plan • Some orders of magnitude
and scenarii
• Various detectors of heavy quarkonia
• Sketch of expectable measurements
Some connected aspects
• Reference ? Open flavour
• Combinatorial background
some features of the experiments)
Hypothesis: energy density thresholds in PbPb at SPS for ’ and
J/ ’ Y’ Y’’
Mass (GeV) 3.097 3.686 9.46 10.02 10.35
R 6.01+-0.19
0.77+-0.17
2.48+-0.07
1.31+-0.21
1.81+-0.17
(KeV) 5.22 2.13 1.3 0.57 0.47
M3 (a.u) 10 0.32 0.037 0.0073 0.0076
M3 (a.u) 0.17 0.042 0.0015 0.00056 0.00042
feeding b,’ b b b2P) ..
2MD or B -M (MeV) 630 40 1100 540 210
•dimuon production psi:psi’: uspilon 1000 : 15 : 1 Dimuon upsilon family: 1 : 0.3: 0.15 ~40% feeding for J/and
• Try to summarize the main trend of the future measurement (statistical)
• This is aiming at order of magnitude and global comparison, from NA50 to LHC, no conclusion can be drawn from precise comparison between experiments
Energy densitiesdensitiesconservative, but consistent, rough estimate, following the PHENIX recent paper, PRL 87, 052301 (2001)
considered fixed ( lower limit at LHC contrarily for upsilon creation time is short (0.2 fm/c)
• <Et>, T, <Pt> Saturation ?
threshold energies estimated through binding energy 40 1
c 240 2.2
’’ 210 2.2
630 3.2
’ 540 3.
b650
700
3.5
Y 1100 ?
’’
c Energy densities extrapolated following this NA50 plot
More precise estimate through lattice QCD calculations
S.Digal, P.petreczky, H.Satz, HEP/ph0106017
J
Central Energy densities (at 1fm/c)
SPS
In-In
SPSPb-Pb
2%
RHIC
Si-Si
RHIC
CuCuRHIC
I-I
RHICAuAu2%
LHCCa-Ca
LHCPb-Pb
dNch/dYY=0
265
*1.15
506
*1.15
91*1.19
225
*1.19487*1.19
785(+9%)
*1.19
327*1.25
2000?*1.25
<Et>per
charged(Gev)
0.8 0.8 0.8 0.8 0.8 0.8 0.9 0.9
S 103 153 40 69 110 148 51 153
1 1 1 1 1 1 1-0.2 1-0.2
2.36 3.04 2.2 3.1 4.2 5 7-35 15-75
R=1.18 A1/3th
NA50 ~2.1GeV/fm3
dN/dY ~ A1.1Rhic 130200 : +9%
Tentative viewing (preliminary)Tentative anwer to « what can we hope to get in future »Significance, Squared (for central collisions) in areas where threshold could be expected
to be compared between energies, these squares of significance should be recalculated for the relevant impact parameter ( central collisions here)
this is only part of the picture due to the others b states at high energies B decays populates all charmonias
Quarkonia versus Open flavour
• Same production mechanism (~gluon fusion)
The ideal reference ?
• But different hadronic or ion effects (energy loss, decays, combinatorial, …) remains
• Z0 good reference too, cleanly measured in CMS
• relative importance of Drell Yan production (qq fusion) % cc and bb (gg fusion) decays ?
• emeasures cc and bb decays
• ee, e Combinatorial background: more critical with energy
(when Psame domain(c) compares with Bc)
• B decay: mixing produce correlated like signs
• Also indirect production of resonances need to measure D and B production
Plausible dn/dy LHC ~ 15 (cc) 1.5 (bb)
Background
PBM
• open charm replaces the pi, K decays in the combinatorial background,
• Combinatorials are more critical than ever, specially for continuum: open flavour are signal and combinatorial background at the same time.
• This technical (method, biases) point has to be studied in detail (P.Crochet et al., M.Gadzinsky et al., D.J et al.,… ), already perhaps at SPS: +/- symetry, combinatorial effects, precisions,
Event mixing
Better suited ?
NA50
SPS
RHIC
PHENIX
LHCALICE
(P.Crochet, P.Braun Munzinger 2001)
For instance: combinatorials in open flavour become dominant at LHC
But this effect decreases with mass(D.C. Zhou, D.J. 1997)
B mixing, exchanging charges, makes the background subtraction more questionnable (P.Crochet 2000)
BD produces correlated low mass pairs (double bump) (Lin,Vogt 1999)
Event mixing is effective here
EpilogueA large set of dimuon measurements will give access to complementary observations for Quarkonia production: c’SPS, RHIC)’’’’), bRHIC, LHC)Y (LHC)•X domains •Energy density •Statistics , backgrounds, references • in addition to ee, , and e measurements, direct measurement of open flavour is needed •Correlations with other observables (central electrons or any observable (strangeness, plane, jets,…) in PHENIX , perhaps ALICE )
• some room for possible upgrades: direct measurement of open charm (phenix), full use of detector capability (L3 trigger for Alice),…open beauty (single leptons) ?...
