Transcript Document
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