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Upsilon Production in Heavy Ions with STAR and CMS. Manuel Calderón de la Barca Sánchez . HIT Seminar Berkeley Lab September 18, 2012. Outline. Bottomonium in heavy ion collisions Upsilon measurements in: STAR CMS Upsilon cross sections in p+p

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upsilon production in heavy ions with star and cms

Upsilon Production inHeavy Ions with STAR and CMS

Manuel Calderón de la Barca Sánchez

HIT Seminar

Berkeley Lab

September 18, 2012.

outline
Outline
  • Bottomonium in heavy ion collisions
  • Upsilon measurements in:
    • STAR
    • CMS
  • Upsilon cross sections in p+p
  • Upsilon nuclear modification factors
  • Conclusions

Manuel Calderón de la Barca Sánchez

quarkonium in the qgp
Quarkoniumin the QGP
  • Heavy quarkonia:
    • Heavy quark bound state are probes of the hot QCD medium
    • Debye screening
      • Matsui & Satz, PLB 178 416 (1986)
    • Sequential Suppression
      • Digalet al., PRD 64 2001 094015
    • Landau damping: Im V.
      • (e.g. Laine et al., JHEP 03 2007 054)

ϒ

T=0

0<T<TC

TC<T

Manuel Calderón de la Barca Sánchez

high t the interaction between the heavy quarks is modified
High T: the interaction between the heavy quarks is modified.
  • Charmonium suppression: longstanding QGP signature
    • Original idea: High T leads to screening
    • Screening prevents heavy quark bound states from forming.
    • J/ysuppression:
      • Matsui and Satz, Phys. Lett. B 178 (1986) 416
    • lattice calculations, indications of screening
      • Nucl.Phys.Proc.Suppl.129:560-562,2004
    • Note: Calculations of internal energy or internal energy

O. Kaczmarek, et al.,

Nucl.Phys.Proc.Suppl.129:560-562,2004

Manuel Calderón de la Barca Sánchez

the heavy quark potential in qcd
The heavy quark potential in QCD
  • Recent news: Heavy quark potential from (quenched) Lattice QCD
    • A.Rothkopf, et al. PRL 108 (2012) 162001
    • Broadening due to collisions with medium (Im V) possibly more important than screening (Re V).

Manuel Calderón de la Barca Sánchez

measuring the temperature
Measuring the Temperature

Quarkonia’s suppression pattern

QGP thermometer

Lattice QCD Calculations:

Dissociation temperatures of quarkonia states

hep-ph/0110406

  • For  production at RHIC and LHC
    • A cleaner probe compared to J/y
      • co-mover absorption → negligible
      • recombination → negligible
    • d-Au: Cold Nuclear Matter Effects
      • Shadowing / Anti-shadowing at y~0
  • Challenge: low rate, rare probe
    • Large acceptance detector
    • Efficient trigger

A .Mocsy, 417th WE-Heraeus-Seminar,2008

  • Expectation:
    • (1S) no melting
    • (2S) likely to melt
    • (3S) melts

Manuel Calderón de la Barca Sánchez

j y puzzles from sps and rhic
J/yPuzzles from SPS and RHIC
  • Similar J/y suppression at the SPS and RHIC!
    • despite 10× higher √sNN
  • Suppression does not increase with local energy density
    • RAA(forward)<RAA(mid)
  • Possible ingredients
    • cold nuclear matter effects
    • sequential melting
    • regeneration
  • What happens for bottomonium?

Manuel Calderón de la Barca Sánchez

charmonium vs bottomonium
CharmoniumvsBottomonium
  • J/y suppression
    • Hot nuclear matter effects: Suppression? Regeneration? Co-mover absorption? Energy loss? Flow?
  • Bottomonium Expectations
    • Cleaner probe of screening, deconfinement.
    • Regeneration?
      • Not a big role for bottomonium
      • Open bottom: sbb ~ 1.34 – 1.84 mb.
      • Open charm: scc~ 551 – 1400 mb.
    • Co-mover absorption?
      • Expected to be small for bottomonium
      • Charmoniumsabs ~ 3 – 4 mb.
      • Bottmoniumsabs ~ 1 mb.
        • Lin & Ko, PLB 503 104 (2001)

Manuel Calderón de la Barca Sánchez

upsilons in star
Upsilons in STAR
  • Upsilons via Triggering, Calorimetry, Tracking, and matching of tracks to calorimeter towers.

Manuel Calderón de la Barca Sánchez

the cms detector
The CMS Detector
  • ϒ event in CMS.

Manuel Calderón de la Barca Sánchez

in p p 200 gev in star
 in p+p 200 GeV in STAR

2006

2009

Phys. Rev. D 82 (2010) 12004

∫Ldt= 7.9 ± 0.6 pb-1N(total)= 67±22(stat.)

∫Ldt = 19.7 pb-1N(total)= 145±26(stat.)

STAR Preliminary

Manuel Calderón de la Barca Sánchez

comparison to nlo pqcd
 Comparison to NLO pQCD
  • Comparison to NLO
  • STAR √s=200 GeVp+p ++→e+e- cross section consistent with pQCDColor Evaporation Model (CEM)

CEM: R. Vogt, Phys. Rep. 462125, 2008CSM: J.P. Lansberg and S. Brodsky, PRD 81, 051502, 2010

Manuel Calderón de la Barca Sánchez

in p p 7 t ev in cms
 in p+p7 TeV in CMS
  • Excellent resolution at midrapidity.
  • Separation of 3 states.

PRD 83,

112004 (2011)

Manuel Calderón de la Barca Sánchez

vs s world data
 vs√s, World Data

STAR Preliminary

STAR √s=200 GeVand CMS √s=7 TeVp+p

++→e+e- cross section consistent with pQCDand world data trend

Manuel Calderón de la Barca Sánchez

in d au 200 gev
 in d+Au 200 GeV

STAR Preliminary

Signal has ~8σ significance

pT reaches ~ 5 GeV/c

∫Ldt= 32.6 nb-1N+DY+bb(total)= 172 ± 20(stat.)

Final results on RdAu coming soon.

LHC pPb run in January/February.

Manuel Calderón de la Barca Sánchez

in au au 200 gev
 in Au+Au 200 GeV

Raw yield of e+e- with |y|<0.5 = 197 ± 36

∫Ldt ≈ 1400 µb-1

Manuel Calderón de la Barca Sánchez

in au au 200 gev centrality
 in Au+Au 200 GeV, Centrality

STAR Preliminary

STAR Preliminary

STAR Preliminary

Peripheral

Central

Manuel Calderón de la Barca Sánchez

bottomonia at 2 76 tev 2010 data
Bottomoniaat 2.76 TeV: 2010 data

pp

PbPb

PRL 107 (2011) 052302

Manuel Calderón de la Barca Sánchez

bottomonia 2011 data
Bottomonia: 2011 data

pp

PbPb

Ratios not corrected for acceptance and efficiency

Manuel Calderón de la Barca Sánchez

in au au 200 gev r aa
 in Au+Au 200 GeV, RAA

Models from M. Strickland and D. Bazow, arXiv:1112.2761v4

  • Indications of Suppression of Upsilon(1S+2S+3S) getting stronger with centrality.
  • Reduced pp statistical uncertainties, increased statistics from 2009 data vs 2006 data.

Manuel Calderón de la Barca Sánchez

2s 1s double ratio cms
ϒ(2S)/ϒ(1S) Double Ratio, CMS
  • Separated ϒ(2S) and ϒ(3S)
  • Measured ϒ(2S) double ratio vs. centrality
    • no strong centrality dependence

Manuel Calderón de la Barca Sánchez

1s nuclear modification factor r aa
ϒ(1S) Nuclear Modification Factor: RAA
  • CMS PbPb at 2.76 TeV
  • In 2010: 7.28 µb−1
    • ϒ(1S) RAA, 3 centrality bins
    • JHEP 1205 (2012) 063
  • In 2011: 150 µb−1
    • ϒ(1S) RAA, 7 centrality bins
    • First results on ϒ(2S) RAA
      • Clear suppression of ϒ(2S)
    • ϒ(1S) suppression
      • Consistent with excited state suppression only
      • ~50% feed down

CMS Preliminary,

arXiv:1208.2826

Manuel Calderón de la Barca Sánchez

comparison rhic and lhc
Comparison: RHIC and LHC
  • STAR measured RAA of ϒ(1S+2S+3S) combined
    • arXiv:1109.3891
    • min. bias value:
  • CMS: separate RAA forϒ(1S) and ϒ(2S)
    • can calculate min. bias RAA of ϒ(1S+2S+3S):

CMS Preliminary,

arXiv:1208.2826

Manuel Calderón de la Barca Sánchez

r aa comparison to models i
ϒ RAA Comparison to models I
  • Incorporating lattice-based potentials, including real and imaginary parts
    • A: Free energy
      • Disfavored, not shown.
    • B: Internal energy
      • Consistent with data vs. Npart
  • Includes sequential melting and feed-down contributions
    • ~50% feed-down from cb.
  • Dynamical expansion, variations in initial conditions (T0, η/S)
    • Data indicate:
      • 428 < T0 < 442 MeV at RHIC
      • 552 < T0 < 580 MeVat LHC
      • for 3 > 4pη/S > 1
  • M. Strickland, PRL 107, 132301 (2011).

Manuel Calderón de la Barca Sánchez

r aa comparison to models ii
ϒ RAAComparison to models II
  • Weak vs. Strong Binding
    • Narrower spectral functions for “Strong” case
    • Ratios of correlators compared to Lattice: favor “Strong” binding case
  • Kinetic Theory Model
    • Rate Equation: dissociation + regeneration
    • Fireball model: T evolution. T ~ 300 MeV

Weak

Binding

Strong

Binding

Manuel Calderón de la Barca Sánchez

r aa comparison to models ii1
ϒ RAA Comparison to models II
  • Comparison to data for “Strong” binding:
    • Mostly consistent with data
    • Little regeneration: Final result ~ Primordial suppression
    • Large uncertainty in nuclear absorption. Need dAu, pPb.

Eur. Phys. J. A (2012) 48: 72

Manuel Calderón de la Barca Sánchez

r aa p t and y dependence
ϒRAA pT and y dependence
  • Indications that suppression is largest at low pT. and mid rapidity.
    • Need more statistics for firmer conclusions.

Manuel Calderón de la Barca Sánchez

the bottom line
The bottom line...
  • STAR and CMS:
    • ϒsuppression vs. Npart.
    • RAAconsistent with suppression of feed down from excited states only (~50%)
  • CMS: First measurement ofϒ(2S) suppression
    • RAA(ϒ(3S)) < 0.09 (95% C.L.)
  • ϒ(1S) RAA consistent with suppression of feed down from excited states only (~50%)
    • Needmore pp statistics to pin down lower-pT double ratio
    • Pinning down the medium properties.
  • Cold nuclear matter:
    • coming soon!

Manuel Calderón de la Barca Sánchez