Measurements of ϒ Production and Nuclear Modiﬁcation Factor … · 2014-06-17 · June 17, 2014...

Measurements of ϒ Production and Nuclear Modification Factor at STAR

Anthony Kesich University of California, Davis

For the STAR Collaboration

Outline

•  Motivation for measuring Upsilons •  The Solenoidal Tracker At RHIC and its triggers •  ϒ production cross section in p+p •  ϒ production in d+Au •  ϒ Nuclear Modification Factor in Au+Au •  LHC Results •  Conclusions

June 17, 2014 RHIC/AGS AUM 2014 - A. Kesich 2

Goal: Quarkonia states in A+A

Charmonia: J/Ψ, Ψ’, χc Bottomonia: ϒ(1S), ϒ(2S), ϒ(3S),χB Key Idea: Quarkonia Melt in the plasma

•  Color screening of static potential between heavy quarks •  Suppression of states is determined by TC and their binding energy •  Lattice QCD: Evaluation of spectral functions ⇒ Tmelting

•  Originaly proposed by Matsui & Satz (1986)

When do states melt?

June 17, 2014 3 RHIC/AGS AUM 2014 - A. Kesich

H. Satz, HP06

A .M

ocsy, Sum

mer Qua

rkon

ium W

orksho

p, BNL, 201

1

Quarkonia at RHIC

•  A cleaner probe compared to J/Ψ • co-mover absorption → negligible • recombination → negligible

• σcc = ~800 µb • σbb= ~ 2µb

•  Challenge: low rate, rare probe –  Large acceptance detector –  Efficient trigger

June 17, 2014 4 RHIC/AGS AUM 2014 - A. Kesich

Why do ϒ at RHIC instead of J/Ψ?

R. Arnaldi, arXiv:1211.2578v1 [n

ucl-‐e

x]

Regenera'on of J/ψ!

RHIC/AGS AUM 2014 - A. Kesich

STAR

EM Calorimeter • |η| < 1 • Full φ coverage • Electron ID via E/p • Event Triggering

Time Projection Chamber • |η| < 1 • Full φ coverage • Tracking and EID via Ionization

June 17, 2014 5

Triggering on ϒ decays


Level 0 Trigger (p+p,d+Au,Au+Au): • Hardware-based • Fires on at least one high tower

Level 2 Trigger (p+p,d+Au): • Software-based • Calculates:

• Cluster energies • Opening angle • Mass

High rejection rate allowed us to sample entire luminosity

ϒ in p+p 200 GeV


)2 (GeV/ceem8 9 10 11 12 130

10

20

30

40

50

60

70 STAR p+p = 200 GeVs

|<0.5ee|y

- -+N+ +N

Comb. Background (CB)

bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

+ -N (a)

∫L dt = 20.0 pb-1��

Nϒ(total)= 152±23(stat. + fit)

Phys

. Rev

. D 8

2 (2

010)

120

04

Sta?s?cal error reduced by a factor of 2!

3X

n=1

B(nS)⇥ d�(nS)

dy= 64± 10+14

�12 pb

For |y|<0.5:

arXiv:1312.3675 acc. by PLB

ϒ in d+Au 200 GeV


∫L dt = 28.1 nb-1��

Nϒ = 46 ± 13 (stat. + fit)

)2 (GeV/ceem8 9 10 11 12 13

Cou

nts

0

5

10

15

20

25

30

35 - -+N+ +N


bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

>coll<N×p+p

+ -NSTAR d+Au = 200 GeVNNs

|<0.5ee|y

(b)

3X

n=1

B(nS)⇥ d�(nS)

dy= 12.2± 3.4+2.1

�1.9 nb


ϒ in p+p 200 GeV, Comparisons


ϒy

-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5

/dy

(pb)

σd× - l+ lB

(1S+

2S+3

S),

ϒ

0

20

40

60

80

100

120

140

160

180

200STAR

= 200 GeVNNs-l+l →(1S+2S+3S) ϒ

(a)

STARppdAu / 1000

PHENIXppdAu / 1000

R. VogtNLO pQCD CEM

ppdAu / 1000

STAR √s=200 GeV p+p ϒ+ϒʹ′+ϒʺ″→e+e- cross section compared to pQCD and world data trend

(GeV)s210 310

(pb)

y=0

/dy|

ϒσ

d⋅ B

-110

1

10

210

310 STAR, p+p, |y|<1.0CFS, p+AE605, p+ACCOR, p+pR209, p+p

R806, p+ppUA1, p+pCDF, p+

CMS, p+pNLO CEM, MRST HO,

=1µ, m/2 m=4.75 GeV/c

(1S+2S+3S)ϒ

STAR Preliminary

CEM: R

. Vogt, Ph

ys. R

ep. 462125, 2008

CSM: J.P. Lansberg and S. Brodsky, PRD

81, 051502, 2010


RdAu vs Rapidity


ϒy

-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5

dAu

(1S+

2S+3

S) R

ϒ

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2 (1S+2S+3S)dAuSTAR R

STAR p+p Syst. UncertaintyPHENIXShadowing, EPS09 (Vogt)

)eEnergy Loss (Arleo, PeignEnergy Loss + EPS09

(b)•  STAR results

consistent with predictions and with unity except for mid-rapidity

•  PHENIX results also consistent with predictions

•  Indication of suppression at y=0 unexpected, but further studies needed


Comparison to E772 Results

•  Upsilon suppression in CM seen before at E772 •  STAR results mostly in agreement with E772


Mass Number (A)10 210

,

/2)

pdσ

A(

pAσ

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

2

ppσ

A/2

dAσ

scaling0.96A

C Ca Fe WAu

(a)

= 40 GeV, 0<y<1.05NNsE772 1S (pA), = 40 GeV, 0<y<1.05NNsE772 2S+3S (pA),

= 200 GeV, |y|<1.0NNsSTAR 1S (dAu),

Fx-0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

α

0.7

0.8

0.9

1

1.1

1.2

1.3 = 40 GeVNNsE772 1S (pA),

= 40 GeVNNsE772 2S+3S (pA), = 200 GeVNNsSTAR 1S+2S+3S (dAu),

= 200 GeVNNsSTAR 1S (dAu),

(b)

arXiv:1312.3675 acc. by PLB arXiv:1312.3675 acc. by PLB

CMS Upsilon pPb Results

•  Double ratio of excited states to the ground state

•  Large to complete suppression in PbPb

•  Slight relative suppression in pPb –  Indication of

nuclear absorption or breakup?


(1S)ϒ(2S)/ϒ (1S)ϒ(3S)/ϒ

pp(1

S)]

ϒ(n

s)/

ϒ /

[xP

b(1

S)]

ϒ(n

s)/

ϒ[

0

0.2

0.4

0.6

0.8

1

1.2

1.4CMS Preliminary

> 4 GeV/cµ

Tp

= 5.02 TeVNNspPb | < 1.93

CMµη|

= 2.76 TeVNNsPbPb | < 2.4

CMµη|

95% upper limit

JHEP 04 (2014) 103

ϒ in Au+Au 200 GeV


)2 (GeV/ceem8 8.5 9 9.5 10 10.5 11 11.5 12

Cou

nts

0

50

100

150

200

250

300

350

= 200 GeVNNsAu+Au |<0.5, Run 10ee|y

- -+N+ +N


bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

>coll<N×p+p

+ -NSTAR Au+Au|<1.0ee = 200 GeV, |yNNs

0-60% centrality

Raw yield of ϒ→e+e- with |y|<1.0 = 254 ± 29 ∫L dt = 1075 µb-1


ϒ in Au+Au 200 GeV, Centrality

June 17, 2014 RHIC/AGS AUM 2014 - A. Kesich 14 )2 (GeV/ceem

8 8.5 9 9.5 10 10.5 11 11.5 12

Cou

nts

0

20

40

60

80

100

120

140


- -+N+ +N


bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

>coll<N×p+p


0-10% centrality

(c)

)2 (GeV/ceem8 8.5 9 9.5 10 10.5 11 11.5 12

Cou

nts

0

10

20

30

40

50

60


- -+N+ +N


bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

>coll<N×p+p


30-60% centrality

(a)

)2 (GeV/ceem8 8.5 9 9.5 10 10.5 11 11.5 12

Cou

nts

0

20

40

60

80

100

120

140


- -+N+ +N


bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

>coll<N×p+p


10-30% centrality

(b)

•  AuAu signal split into three centrality bins

•  Grey curve indicates line shape if no suppression


ϒ in Au+Au 200 GeV, RAA


Mod

els

from

M. S

tric

klan

d an

d D

. Baz

ow, a

rXiv

:111

2.27

61v4

A

. Em

eric

k et

al.,

Eur

. Phy

s. J.

A48

(201

2) 7

2

• Consistent increase in suppression with greater Npart in both Au+Au and U+U • Strickland models predict temperature range of 428 MeV < T < 442 MeV

partN0 50 100 150 200 250 300 350 400

AA

,dA

(1S+

2S+3

S) R

ϒ

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

(1S+2S+3S)ϒSTAR = 200 GeVNNs |<1.0

ϒ|y

STAR Au+Au

STAR d+Au

STAR U+U (prelim)

p+p Stat.+Fit Uncertainty

Common Normalization Syst.

STAR Au+Au, Centrality IntegratedSTAR U+U, Cent. Integrated, Prelim

Strickland-Bazow ModelEmerick-Zhao-Rapp Model

(a)


ϒ(1S) in Au+Au 200 GeV, RAA


Mod

els

from

M. S

tric

klan

d an

d D

. Baz

ow, N

ucle

ar P

hysi

cs A

879

, 25-

58 (2

012

Y. L

iu, B

. Che

n, e

t. al

., ar

Xiv

:100

9.25

85

• RAA of ϒ(1S) is consistent with 1 in dAu and peripheral and mid-central AuAu • Indication of suppression consistent with model calculation in central AuAu

partN0 50 100 150 200 250 300 350 400

AA

,dA

(1S)

Rϒ

0

0.5

1

1.5

2

2.5

STAR Au+Au

STAR d+Au

p+p Stat.+Fit Uncertainty

Common Normalization Syst.

STAR Au+Au, Centrality Integrated

Strickland-Bazow Model

Liu-Chen Model

(1S)ϒSTAR = 200 GeVNNs |<1.0

ϒ|y

(c)


CMS Upsilon PbPb Results

•  CMS also sees increasing suppression with more central collisions

•  Results are consistent with predictions within statistics

•  Suppression level comparable to STAR


PRL 109 (2012) 222301

LHC: RAA vs Rapidity

•  LHC shows increased suppression at higher y – Unexpected and opposite of predictions

•  Role of CNM or Regeneration? June 17, 2014 RHIC/AGS AUM 2014 - A. Kesich 18

Javier Castillo

Comparison with models – Transport

• RAA of inclusive Υ(1S) in Pb-Pb collisions at √sNN = 2.76 TeV

• A. Emerick et al., [EPJ A48 (2012) 72]– Transport model– Suppression of Υ resonances by the QGP

• Mainly of the higher mass states– Small regeneration component included– Feed down from higher mass states included– CNM included via an “effective” σABS = 0–2 mb

11

Model does not reproduce the strong rapidity dependence of the RAA and underestimates the Υ(1S) suppression at forward rapidity

• Stronger suppression of direct Υ(1S)?• Role of regeneration?• Role of CNM?

PbPb @ 2.76 TeV arXiv:1405.4493

⟩partN⟨0 50 100 150 200 250 300 350

AA

R

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Total Primordial Regenerated

-1bµ = 69 intL = 2.76 TeV, NNsALICE: Pb-Pb

> 0Tp < 4, y(1S), 2.5 < ϒInclusive

y-4 -3 -2 -1 0 1 2 3 4

AA

R

0

0.2

0.4

0.6

0.8

1

1.2

1.4

Total Primordial Regenerated

> 0Tp(1S), ϒ = 2.76 TeV, inclusive NNsPb-Pb

, 0%-90% (open: reflected)-1bµ = 69 intLALICE: , 0%-100%-1bµ = 150 intLCMS:

CMS: PRL109 (2012) 222301arXiv:1405.4493

Binding Energy

•  STAR and CMS quarkonia RAA results show suppression for all states measured

•  Increased suppression with decreased binding energy as prediction by Debye screening


Binding Energy (GeV)0 0.2 0.4 0.6 0.8 1 1.2 1.4

AA

R

0

0.2

0.4

0.6

0.8

1

1.2

(1S)ϒ0-10%Centrality

(2S+3S), 95% limitϒ0-60% Centrality

>5 GeV/cT

, pψJ/0-10% Centrality

STAR Inclusive Quarkonium Measurements = 200 GeV, |y|<1NNsAu+Au,

Raphael Granier de Cassagnac Quark Matter 2014, Darmstadt

Five quarkonia • The suppression of 5 quarkonia

was observed in PbPb – Well-ordered with binding energy – Inclusive bottomonia – Charmonia pT > 6.5 GeV + pT-inclusive J/ψ from ALICE less suppressed than at RHIC, calling for recombination

• Quarkonia melt in quark matter

41

Talks by Moon & Abdulsalam PRL109 (2012) 2220301,

PAS-HIN-12-014, PAS-HIN-12-007

Y(1S)

Y(2S) J/ψ

arXiv:1312.3675 acc. by PLB Raphael Granier de Cassagnac, QM14

Outlook


8 9 10 11 12 130

20

40

60

80

100

120

140 STAR Prelminary = 200 GeVNNsAu+Au

|<0.5, Run 11ee

|y

0-60% Centrality

- -+N+ +N

+ -NComb. Background (CB)

bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

ϒ + bIntegral of CB + DY + b

)2 (GeV/ceem8 9 10 11 12 130

50

100

150

200

250 STAR Prelminary = 500 GeVNNsp+p

|<0.5, 0<pT<10ee|y

- -+N+ +N

+ -N


bCB + Drell-Yan + b

(1S+2S+3S)ϒ + bCB + DY + b

ϒ + bIntegral of CB + DY + b

Au+Au @ 200 GeV, 2011 •  Same setup as in 2010 •  ~2800 ub-‐1

Au+Au @ 200 GeV, 2014 •  ~13.8 nb-‐1 sampled by MTD •  MTD and HFT full installed

p+p @ 500 GeV, 2011 •  High energy doubles Upsilon cross sec?on •  Excited-‐to-‐ground ra?o •  PT spectrum •  Preliminary results available soon •  ~22 pb-‐1

Outlook


ϒ with STAR MTD

• A detector with long-MRPCs – Covers the whole iron bars and leave the gaps in between uncovered. – Acceptance: 45% at ||<0.5 – 122 modules, 1464 readout strips, 2928 readout channels

• Long-MRPC detector technology, electronics same as used in STAR-TOF • Run 2012 -- 10%; 2013 – 60%+; 2014 – 100%: ϒ via +-

22

MTD (MRPC)

[email protected]

PartN0 50 100 150 200 250 300 350

AA

R0

0.2

0.4

0.6

0.8

1-µ

+µ→(1S)ϒ

-µ+µ→(2S)ϒ

-µ+µ→(3S)ϒ

, |y|<0.5-e+e→(1S+2S+3S)ϒ

STAR Muon Telescope Detector Au+Au-1 p+p, 20 nb-160 pb

7

Intermediate Silicon Tracker:

single-sided double-metal silicon pad

sensors with 600 µm × 6 mm pitch

σr-φ: 170 µm σz: 1800 µm

radius: 14 cm X/X0 < 1.5 % See details at poster M-30 by Yaping Wang

The task of SSD and IST is to guide the track from TPC to the innermost PXL detector with high hit density.

Silicon Strip Detector:

existing detector with new faster electronics

double sided silicon strip modules with 95 µm pitch

σr-φ: 20 µm

σz: 740 µm

radius: 22 cm

X/X0: 1 %

HFT Design�

Qiu Hao

Heavy Flavor Tracker

Adapted from J. Bielcik, Hard Probes 2013

Conclusions

•  Measured ϒ production in p+p, d+Au, and ��Au+Au collisions at 200 GeV

•  Au+Au results consistent with 2S and 3S suppression

•  d+Au results hint at additional suppression beyond model calculations – Further studies warranted

•  New muon channel will enhance and compliment our electron measurements



Thank you

Measurements of ϒ Production and Nuclear Modiﬁcation Factor … · 2014-06-17 · June 17, 2014...

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