Sean Kelly, QWG 9/03 Prospects for Quarkonia Physics In Media at the LHC.

Sean Kelly, QWG 9/03

Prospects for Quarkonia Physics In Media at the

LHC


Outline

•Ultra High Energy Nuclear Physics

•Why are Quarkonia Important ?

•Experiments, Coverage, Rates

• Summary and Outlook

cc J/


Ultra High Energy Nuclear Physics

Temperature or Density

Attempt to reproduce the state of nuclear matter a few μs after the Big Bang

Long range confining potential is screened

Spontaneously broken approximate SU(2) flavor symmetry is restored


The Importance Of Quarkonia

Color Screening

cc

state J/ c

' (1s) b

(2s) b' (3s)

Mass [GeV} 3.096 3.415 3.686 9.46 9.859 10.023 10.232 10.355B.E. [GeV] 0.64 0.2 0.05 1.1 0.67 0.54 0.31 0.2

Td/Tc --- 0.74 0.15 --- --- 0.93 0.83 0.74

hep-ph/0105234


Time Zones

precursor color singlet quarkonia

PCM & clust. hadronization

NFD

NFD & hadronic TM

PCM & hadronic TM

CYM & LGT

string & hadronic TM

pre-resonance absorbtion

pre-equilibrum effects

color screening, thermal production

break up by co-moving hadrons

cc J/

quarkonia local timemedium local time


AA Cross Sections For Quarkonia

Spectators

Spectators

Participants

A1/3

(dN/dy)AA = Nbinary (dN/dy)pp

Nbinary ~ A4/3 geo ~ A2/3

AA = A2 ppBr incA2 (b)

J/ 48930

879

304

78.8

44.4

Pb + Pb s = 5.5 TeV

L = 5 x 1026 cm-2 s-1

From a one month run with a 40% duty cycle

Lint = 0.5 nb -1

N J/μμ = 2.54 x 107

N μμ = 1.52 x 105


Experimental Coverage & Rates

Pythia 6.150 tuned to NLO extrapolated to LHC*

*Draft Yellow Paper ”Hard Probes In Heavy Ion Collisions at the LHC: Heavy Flavor Physics”

Simple , pt cuts for detector apperture.


ALICE

J/ μ+μ-, J/ e+e-

μ+μ-, e+e-

Forward Muon Spectrometer

Central detectors are capable of electron pion discrimination (pt>1 GeV) and triggering (pt>3 GeV)


ALICE J/+-

central e+e-

|| < 0.9

pt > 3.0 GeVNgeo=2.1x104


ALICE J/e+e-

forward +-

2.4 < < 4.0

p > 4.0 GeVNgeo=8x105

Low pt coverage


CMS

|| < 1.4 (barrel) || < 2.4 (end cap)

pt > 3.0 GeV || < 1.4,

ptot > 4.0 GeV 1.4<||< 2.4

Measure J/ μ+μ-, μ+μ-

Inner Silicon Tracker 2-4% occupancy in the pixels layers 18% in the outer 5 Si strip detectors (dN/d ~ 8000)

EMCAL is 1.3m from the interaction point, >99% of the background form decay muons is rejected


ATLAS

Measure J/ μ+μ-, μ+μ-

Inner Silicon Tracker <1% occupancy in the inner 3 pixel layers, 6-15% occupancy in the outer 4 Si strip layers (dN/d ~ 8000)

Independent momentum measurement in muon spectrometer. Need inner tracker matching for resolution on the states.

|| < 1.0 (barrel) , || < 2.5 (endcap)

pt > 3.0 GeV (barrel)

ATLAS


Rate Summary

ALICE e+e- ALICE μ+μ- CMS ATLAS

J/ 2.1x104 8.0x105 3.7x104 2.5x104

1.4x104 5.0x103 2.6x104 2.1x104

Lint = 0.5 nb -1

J/ yields are sensitively dependent on low momentum threshold.

Trigger efficiency is an issue for CMS & ATLAS

Plenty of signal to study the suppression pattern of J/ and at the LHC


Saturation Physics

The ratio of the EKS98 corrected nuclear gluon distribution to CTEQ5L

overlapping color sources lead to the saturation of the gluon phase space in the initial state nuclear wavefunction


x coverage

Coverage over 5 decades in x for which nuclear effects in the gluon density are expected to manifest

The ratio of the EKS98 corrected nuclear gluon distribution to CTEQ5L


Chasing The

Can we measure

c

c


c0

c1 c2

Outlook

Can we measure

c

/ vs pt is very

interesting


From c

state J/ c

' (1s) b

(2s) b' (3s)

Mass [GeV} 3.096 3.415 3.686 9.46 9.859 10.023 10.232 10.355B.E. [GeV] 0.64 0.2 0.05 1.1 0.67 0.54 0.31 0.2

Td/Tc --- 0.74 0.15 --- --- 0.93 0.83 0.74

Same binding

energy

cc J/

Quarkonia local time gets dilated as a function of pt. This make the ratios of directly produced quarkonia a probe of the plasma lifetime


Summary

Measurements are underway at RHIC of the J/ suppression pattern

LHC will extend the study of in media quarkonia to the upsilon family of resonances

Saturation physics and nuclear modifications to the gluon pdf studied down to x ~ 10-5

Potential to reconstruct the states and study the time evolution of the medium.

Sean Kelly, QWG 9/03 Prospects for Quarkonia Physics In Media at the LHC.

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