The first Workshop on STAR MTD Production and Related Physics

Hefei, Anhui, China, Marth 30

th

– April 1

st

, 2011

J/

y

Results from STAR Zebo Tang

University of Science and Technology of China (USTC) Center of Particle Physics and Technology

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 1

QCD phase diagram

03/30/2011

Net Baryon Density

Zebo Tang, STAR MTD Workshop, Hefei 2

Outline

• • • • •

Introduction

– J/ y – J/ y as a classic probe of QGP production mechanism in p+p collisions

Electron identification and J/

y

reconstruction Results

– – –

J/

y

spectra in p+p collisions J/

y

-hadron correlation in p+p collisions J/

y

suppression in A+A collisions

J/

y

with MTD Summary

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 3

J/

y

melting in QGP – Signature of deconfinement

J/

y

dissociation due to color screening



Signature of the QGP formation

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 4

QGP thermometer

Quarkonium dissociation temperatures – Digal, Karsch, Satz Model dependent

Plasma thermometer ?

Dissociation temperature depends on binding energy



QGP temperature

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 5

Other effects

• • • • • • •

Feeddown

(sequential suppression)

Cronin effect Nuclear absorption Hadronic phase dissociation Gluon saturation Formation time effect … J/

y

suppression at low p T maybe only from excited stats (

y

’,



c )

F. Karsch, D. Kharzeev and H. Satz, PLB 637, 75 (2006)

60% from direct J/

y

: not suppressed 30%



c and 10%

y

’: dissociated

NA50, EPJ39,335 NA60, QM05 H. Satz, Nucl. Phys. A (783):249-260(2007)

Precise measurements at broad kinetic range and systems are needed!

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 6

Charmonium production mechanism



Color singlet model (CSM), LO

underpredicted CDF data by order of magnitude 

Color octet model (COM), LO

good agreement with CDF cross section disagreement with CDF polarization

LO NRQCD

LO CSM 03/30/2011

J/

y CDF measurement: PRL79,572 3 S 1

J/

y LO COM

Know your reference!

Zebo Tang, STAR MTD Workshop, Hefei 7

Charmonium production mechanism



Color singlet model (CSM), LO

underpredicted CDF data by order of magnitude 

Color octet model (COM), LO

good agreement with CDF cross section disagreement with CDF polarization

LO NRQCD



CSM*, NLO

better agreement NNLO* applicable at p T >5-7 GeV/c 

COM*

improvement of polarization, NLO will come, valid at p T >3 GeV/c 03/30/2011

Decay feeddown (CDF):

y

(2s):

7%-15%, slightly increase with p T 

c0,1,2 :

~30%, slightly decrease with p T

B:

Strong p T dependence

Know your reference!

Zebo Tang, STAR MTD Workshop, Hefei 8

MRPC ToF Barrel FPD BBC

STAR detector

MTD EMC Barrel EMC End Cap FMS

TPC

PMD FTPC trigger computing DAQ1000 HLT TPC+BEMC+(MRPC-TOF) in this analysis

2 

coverage at mid-rapidity (

| h |<1

)

COMPLETE

Ongoing

R&D

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 9

Electron identification (TPC only)

Note: electron yield is much less than hadrons x sigma deviation from electron dE/dx curve With TPC only: • No electron ID at low p T • Eifficult to get a good electron sample at high p T • Possible to get a electron sample with reasonable purity at intermediate p T 03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 10

Electron ID (EMC)

Online fast trigger: • Enhance high p T electron • Enhance recorded luminosity 03/30/2011 (Dh x Df= 0.05x0.05) ~5X 0 Offline cuts: Matching between EMC and TPC Deposited energy (BTOW) Shower shape (BSMD)

Low p T J/

y

:

Intermediate p T

High p T J/

y: electrons (TPC only) high p T electron (TPC+EMC) + Intermediate p T electron (TPC only) Zebo Tang, STAR MTD Workshop, Hefei 11

Low-p

T

J/

y

signals

200GeV p+p L2 J/ y trigger 200GeV d+Au MB trigger 200GeV Cu+Cu MB trigger 200GeV Au+Au MB trigger 03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 12

High-p

T

J/

y

signals

03/30/2011

2009

STAR, PRC80, 041902(R), 2009

• Tight cuts for correlation study • Spectra in progress Zebo Tang, STAR MTD Workshop, Hefei 13

J/

y

spectra in p+p and Cu+Cu at 200 GeV

~3 orders •

Significantly extend p T range of previous measurements in p+p at RHIC to 14 GeV/c

•

Agreement of charm measurements between STAR and PHENIX Online fast trigger is important with limited DAQ rate and Data processing capability

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 14

J/

y

p

T

spectra

03/30/2011

STAR, PRC80, 041902(R), 2009 STAR, PRC80, 041902(R), 2009

Color singlet model:

direct NNLO* still miss the high p T part.

P. Artoisenet et al., Phys. Rev. Lett. 101, 152001 (2008), and J.P. Lansberg private communication .

LO CS+CO

: better agreement with the measurements, leave little room for higher charmonium states and B feeddown.

private communication.

G. C. Nayak, M. X. Liu, and F. Cooper, Phys. Rev. D68, 034003 (2003), and

J/ y x T scaling at high p T :

n=5.6

±

0.2

CS+CO prediction)

Soft processes

affect low p T J/ y (close to production Zebo Tang, STAR MTD Workshop, Hefei 15

Constrain bottom contribution

J/

y

-h correlation

STAR, PRL95, 152301 (2005) STAR, PRC80, 041902(R), 2009

STAR Preliminary h-h correlation

• •

No significant near side J/

y

-hadron azimuthal angle correlation Correlation show low B contribution (13



5) %

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 16

Correlations from Run9

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 17

B



J/

y

/ inclusive J/

y

PRC80, 041902(R), 2009 PLB200, 380, 1988 PLB370, 239, 1996 PRD71, 032001, 2005

03/30/2011 • • •

Consistent with previous results No significant beam energy dependence Can be used to constrain B production

Zebo Tang, STAR MTD Workshop, Hefei 18

Associated hadron p

T

spectra

STAR, PRL95, 152301 (2005)

Near side :

Consistent with no associated hadron production

Away side : Consistent with h-h correlation



away-side seems to come from gluon/light quark fragmentation

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 19

Low-p

T

J/

y

in Au+Au 200 GeV

STAR Preliminary

PHENIX: Phys. Rev. Lett. 98, 232301 (2007) • • Model (green band) includes: color screening in QGP, dissociation in hadronic phase, statistical recombination, B → J/ y feed-down and formation time effects New Au+Au results with minimum inner material soon (5x higher statistics with TOF) 03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 20

High-p T J/

y

in Cu+Cu 200 GeV

STAR, PRC80, 041902(R), 2009

   STAR Cu+Cu 0-20%:  R AA (p T >5) = 1.4

 0.4

The only hadron measured to be not suppressed at high p in RHIC Heavy-ion collisions



Contrast to open charm. CS vs. CO? CNM effect

Time?

R AA >AdS/CFT+Hydro, 99% C.L.

Contrast to AdS/CFT+Hydro prediction

 0.2

Cu is too small?

？

T

Formation

A. Adil and I. Vitev, Phys. Lett. B649, 139 (2007), and I. Vitev private communication; S. Wicks et al., Nucl. Phys. A784, 426 (2007), and W. A. Horowitz private communication.

H. Liu, K. Rajagopal and U.A. Wiedemann PRL 98, 182301(2007); T. Gunji, J. Phys.G 35, 104137 (2008)

2-component models describes the overall trend

X. Zhao and R. Rapp, Phys. Lett. B664:253, 2008; Y.P. Liu, et al., Phys.Lett.B678:72-76,2009

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 21

91 ± 22 4 s

J/

y

in Au+Au @ 39 GeV

82 ± 13 6 s • • •

Clear signal seen in 39GeV Au+Au with Expect ~1000 (13 Able to cover p T

s

) J/

y

from full MB data range (0, 5) GeV/c TOF dE/dx after TOF cut

•

Much higher statistics and recorded integral luminosity at 62 and 200GeV

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 22

Muon Telescope Detector (MTD)

Advantages over electrons

no  conversion much less Dalitz decay contribution less affected by radiative losses in the materials

Trigger capability for low to high p T central Au+Au collisions

High m /hadron enhancement

J/

y

in

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei S/B~2 in central Au+Au 23

MTD in RHICII era

J/

y

J/

y

MTD+HFT:

Trigger and topologically reconstruct B  J/ y , J/ y  mm

MTD+TOF:

J/ y +ccbar?

Charmonium higher states?

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 24

Summary



In 200 GeV p+p collisions



Extended previous spectra measurements to 14 GeV/c



Large S/B ratio allows correlation study

 B has sizeable (not dominant) contribution at high p T  high-p T J/ y away side hadron production consistent with gluon/quark fragmentation 

In heavy-ion collisions



First observation of no suppression for hadron at high p T at STAR in 200GeV Cu+Cu collisions



Clear signals seen in 39 GeV Au+Au with TOF, covers p T from 0 to 5 GeV/c

It is just a start!

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei

Thank you!

25

Extra

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 26

Future dramatic improvement of J /

y

at low p

T

• • • EMC+TOF+HFT (large acceptance): J/ y production Different states predicted to melt at different T in color medium Charmonia (J/ y ), bottonia (  )

dE/dx after TOF cut

Quarkonium dissociation temperatures – Digal, Karsch, Satz PHENIX Acceptance: | h |<0.35, STAR TOF-Upgrade Acceptance: | h |<0.9, f =2*  /2 f =2* 

J /

y

yields from 1 billion minbias Au+Au events: 43.8x10

-9 /0.040x10

9 *292*0.5*1.8*0.5= 144,000



0.3% v 2 error

s

J/

y s

pp N N bin

e

y R AA

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei pT (e)>1.5 GeV/c 27

Detector upgrades: HFT and MTD

Heavy Flavor Tracker:

 

e + e rejection Rejection power: ~16 Topologically reconstruct J/

y

from B decay Muon Telescope Detector: Muon identification

Prototype in run VII

n

s 

>0

STAR Preliminary simulation 03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 28

Jpsi-h correlation from PYTHIA

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 29

J/

y

measurements in Heavy Ion Collisions

NA60, QM08 •

Due to color screening, J/

y

was thought be dissociated in the medium.

T. Masui and H. Satz, Phys. Lett. B178, 416 (1986).

•

At RHIC, the suppression at low p T is similar to at SPS at similar N part : recombination due to large charm cross section.

P. Braun-Munzinger and J. Stachel, Phys. Lett. B490,196 (2000); L. Grandchamp and R. Rapp, Phys. Lett. B523, 60 (2001); M. I. Gorenstein et al., Phys. Lett. B524, 265 (2002); R. L. Thews, M. Schroedter, and J. Rafelski, Phys. Rev. C63, 054905 (2001); Yan, Zhang and Xu, Phys.Rev.Lett.97, 232301 (2006); PHENIX: Phys.Rev.Lett.98, 232301,2007. •

At SPS, suppression decreases versus p T : Cronin effect , Nuclear absorption and formation time effect.

M. C. Abreu et al., Phys. Lett. B499, 85 (2001); X. Zhao, WWND2008

;

X. Zhao and R. Rapp, hep-ph/07122407; X. Zhu, P. Zhuang, PRC67, 067901(2003) 03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 30

High p

T

J/

y

in heavy ion collisions

How the formation time effect, jet energy loss and hot wind dissociation affect the high p T J/psi in the medium: 2-component approach: dissociation + recombination

R AA increases slightly with p T including formation time and B decay X. Zhao, WWND2008; X.Zhao and R. Rapp, hep-ph/07122407

Formation time effect:

R AA increases with p T (formed out of medium)

K. Farsch and R. Petronzio, PLB 193(1987), 105 ; J.P. Blaizot and J.Y. Ollitrault, PLB 199(1987),499

Jet energy loss: open charm strongly suppressed observed in the medium AdS/CFT + Hydro: R AA decreases versus p T

03/30/2011

STAR: PRL98(2007) 192301

Zebo Tang, STAR MTD Workshop, Hefei 31

PLB499,85 and NPA774,59

NA50, 158 AGeV

Compare to SPS

NA60, QM08 RHIC: Cu+Cu, , consistent with no suppression at p

NN

200

GeV

T > 5 GeV/c SPS: In+In, , consistent with no suppression at p

NN

17.3

GeV

T > 1.8 GeV/c Similar trend also observed at SPS, might from different physics origin 03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 32

J/

y

-h correlation from PYTHIA

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 33

Summary

J/ y in p+p and Cu+Cu collisions: • • p T spectra in p+p:

extended to ~14 GeV/c

• •

follows x T scaling with n=5.6 at p T >5 GeV/c, deviates from scaling at low p T

J/ y -hadron azimuthal correlation in p+p:

no significant near side correlation constrain the contribution from B



J/

y

+X away-side spectra consistent with h-h correlation



gluon or light quark fragmentation

• J/ y R AA

indication of R AA increasing at high p T

• • • • • production mechanisms:

described by NRQCD soft processes affect low p T production constrain decay contribution constrain B production and B



e constrain production mechanism: CSM or COM

•

medium properties

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 34

G. Lin, Yale Univ.

Single Muon and J/ y Efficiency

J/

y

efficiency 1. muon efficiency at | η|<0.5: 36%, pion efficiency: 0.5-1% at p T >2 GeV/c 2. muon-to-pion enhancement factor: 50-100 3. muon-to-hadron enhancement factor: 100-1000 including track matching, tof and dE/dx 4. dimuon trigger enhancement factor from online trigger: 10-50 in central Au+Au collisions

J/

y

measurements in Heavy Ion Collisions

NA 50, PLB 477,28 (2000)

SPS: Anomalous suppression



Significant evidence of deconfinement in central Pb+Pb

PLB 477,28 (2000)

RHIC: Similar suppression as SPS, why?

Balance of dissociation and regeneration? Other effects

03/30/2011 Zebo Tang, STAR MTD Workshop, Hefei 36