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 ID: 638049
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Slide1
Upsilon Production inHeavy Ions with STAR and CMS
Manuel Calderón de la Barca Sánchez
HIT Seminar
Berkeley LabSeptember 18, 2012.Slide2
OutlineBottomonium in heavy ion collisionsUpsilon measurements in:STARCMS
Upsilon cross sections in p+pUpsilon nuclear modification factorsConclusions9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez
2Slide3
Quarkonium in the QGPHeavy quarkonia
: Heavy quark bound state are probes of the hot QCD medium Debye screening Matsui & Satz, PLB 178 416 (1986)Sequential Suppression
Digal et al., PRD 64 2001 094015Landau damping:
Im V. (e.g. Laine et al., JHEP 03 2007 054)9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez3
T
C
<
T
0<T
<T
C
T=0
ϒSlide4
4High T: the interaction between the
heavy quarks is modified.Charmonium suppression: longstanding QGP signatureOriginal idea: High T leads to screeningScreening prevents heavy quark bound states from forming.
J/y
suppression: Matsui and Satz, Phys. Lett. B 178 (1986) 416lattice calculations, indications of screeningNucl.Phys.Proc.Suppl.129:560-562,2004 Note: Calculations of internal energy or internal energyO. Kaczmarek, et al.,Nucl.Phys.Proc.Suppl.129:560-562,2004 9/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca SánchezSlide5
The heavy quark potential in QCDRecent news: Heavy quark potential from (quenched) Lattice QCDA.Rothkopf
, et al. PRL 108 (2012) 162001
Broadening due to collisions with medium (Im V)
possibly more important than screening (Re V).9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez5Slide6
6Measuring the Temperature
hep-ph/0110406
Dissociation temperatures of quarkonia states
Lattice QCD Calculations:
Quarkonia’s suppression pattern
QGP thermometer
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
Expectation:
(1S) no melting
(2S) likely to melt
(3S) melts
A .Mocsy
, 417th WE-Heraeus-Seminar,2008
9/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca SánchezSlide7
J/y Puzzles from SPS and RHIC
Similar J/y suppression at the SPS and RHIC!despite 10× higher √sNNSuppression does not increase with local energy densityRAA(forward)<RAA(mid)
Possible ingredientscold nuclear matter effectssequential meltingregeneration
What happens for bottomonium?79/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca SánchezSlide8
Charmonium vs Bottomonium
J/y suppressionHot nuclear matter effects: Suppression? Regeneration? Co-mover absorption? Energy loss? Flow? Bottomonium Expectations
Cleaner probe of screening, deconfinement.Regeneration?
Not a big role for bottomoniumOpen bottom: sbb ~ 1.34 – 1.84 mb.Open charm: scc ~ 551 – 1400 mb.Co-mover absorption?Expected to be small for bottomoniumCharmonium sabs ~ 3 – 4 mb.Bottmonium sabs ~ 1 mb. Lin & Ko, PLB 503 104 (2001) 9/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca Sánchez
8Slide9
Upsilons in STARUpsilons via Triggering, Calorimetry, Tracking, and matching of tracks to calorimeter towers.
9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez9Slide10
The CMS Detector9/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca Sánchez10
ϒ event in CMS.Slide11
in p+p 200 GeV in STAR
9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez11
∫
L dt = 7.9 ± 0.6 pb-1N(total)= 67±22(stat.)
Phys. Rev. D
82 (2010) 12004
∫
L
dt
= 19.7
pb
-
1
N
(total
)=
145±26(
stat.)
2006
2009
STAR PreliminarySlide12
Comparison to NLO pQCD
Comparison to NLOSTAR √s=200 GeV p+p ++→e+
e- cross section
consistent with pQCD Color Evaporation Model (CEM)9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez12CEM: R. Vogt, Phys. Rep. 462125, 2008CSM: J.P. Lansberg and S. Brodsky, PRD 81, 051502, 2010Slide13
Excellent resolution at midrapidity.Separation of 3 states.9/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca Sánchez13 in p+p
7 TeV
in CMSPRD 83, 112004 (2011)Slide14
vs √s, World Data
9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez14
STAR
√s=200 GeV and CMS √s=7 TeV p+p ++→e+e- cross section consistent with pQCD and world data trend
STAR PreliminarySlide15
in d+Au 200 GeV
9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez15
∫
L dt = 32.6 nb-1N
+DY+bb(
total)= 172 ± 20(
stat.)
Signal has ~8σ significance
p
T
reaches ~ 5
GeV/c
STAR Preliminary
Final results on
RdAu
coming soon.
LHC
pPb
run in January/February.Slide16
in Au+Au 200 GeV
9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez16
Raw yield of
e+e- with |y|<0.5 = 197 ± 36∫L dt ≈ 1400 µb-1Slide17
in Au+Au 200 GeV, Centrality
9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez17
Peripheral
Central
STAR Preliminary
STAR Preliminary
STAR PreliminarySlide18
Bottomonia
at 2.76 TeV: 2010 data18
pp
PbPbPRL 107 (2011) 0523029/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca SánchezSlide19
Bottomonia: 2011 data
19pp
PbPb
Ratios not corrected for acceptance and efficiency9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca SánchezSlide20
in Au+Au 200 GeV, R
AA9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez20
Models from M. Strickland and D.
Bazow, arXiv:1112.2761v4Indications of Suppression of Upsilon(1S+2S+3S) getting stronger with centrality.Reduced pp statistical uncertainties, increased statistics from 2009 data vs 2006 data.Slide21
ϒ(2S)/ϒ(1S) Double Ratio, CMS
Separated ϒ(2S) and ϒ(3S)
Measured ϒ(2S) double ratio vs. centrality
no strong centrality dependence219/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca SánchezSlide22
ϒ(1S) Nuclear Modification Factor: RAA
CMS PbPb at 2.76 TeVIn 2010: 7.28 µb−1
ϒ(1S) RAA, 3 centrality binsJHEP 1205 (2012) 063
In 2011: 150 µb−1ϒ(1S) RAA, 7 centrality binsFirst results on ϒ(2S) RAA Clear suppression of ϒ(2S)ϒ(1S) suppression Consistent with excited state suppression only ~50% feed down229/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca SánchezCMS Preliminary,
arXiv:1208.2826Slide23
Comparison: RHIC and LHC
STAR measured RAA of ϒ(1S+2S+3S) combinedarXiv:1109.3891min. bias value:CMS: separate RAA for
ϒ(1S) and ϒ(2S)
can calculate min. bias RAA of ϒ(1S+2S+3S):239/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca SánchezCMS Preliminary,arXiv:1208.2826Slide24
ϒ RAA Comparison to models I
Incorporating lattice-based potentials, including real and imaginary partsA: Free energy Disfavored, not shown. B: Internal energy Consistent with data vs. NpartIncludes sequential melting and feed-down
contributions~50% feed-down from c
b.Dynamical expansion, variations in initial conditions (T0, η/S)Data indicate: 428 < T0 < 442 MeV at RHIC552 < T0 < 580 MeV at LHC for 3 > 4pη/S > 1M. Strickland, PRL 107, 132301 (2011).9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez24Slide25
ϒ RAA Comparison to models II
Weak vs. Strong BindingNarrower spectral functions for “Strong” caseRatios of correlators compared to Lattice: favor “Strong” binding caseKinetic Theory ModelRate Equation: dissociation + regenerationFireball model: T evolution. T ~ 300 MeV9/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca Sánchez
25StrongBindingWeakBindingSlide26
ϒ RAA Comparison to models IIComparison to data for “Strong” binding:
Mostly consistent with dataLittle regeneration: Final result ~ Primordial suppressionLarge uncertainty in nuclear absorption. Need dAu, pPb.9/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez
26
Eur. Phys. J. A (2012) 48: 72Slide27
ϒ RAA pT and y dependence
Indications that suppression is largest at low pT. and mid rapidity. Need more statistics for firmer conclusions.9/18/12 HIT Seminar, Berkeley Lab
Manuel Calderón de la Barca Sánchez
27Slide28
The
bottom line...
STAR and CMS:ϒ
suppression vs. Npart.RAA consistent with suppression of feed down from excited states only (~50%)CMS: First measurement ofϒ(2S) suppressionRAA(ϒ(3S)) < 0.09 (95% C.L.)ϒ(1S) RAA consistent with suppression of feed down from excited states only (~50%)Need more pp statistics to pin down lower-pT double ratioPinning down the medium properties.Cold nuclear matter:coming soon!289/18/12 HIT Seminar, Berkeley Lab Manuel Calderón de la Barca Sánchez