Download s NN

Study the QCD Phase Structure
in High-Energy Nuclear Collisions
Nu Xu(1,2)
Outline:
1) Introduction
2) Selected results from RHIC BES-I
3) Selected day-I observables for CBM
(1) College
of Physical Science & Technology, Central China Normal University, China
(2) Nuclear Science Division, Lawrence Berkeley National Laboratory, USA
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
1/23
Exploring QCD Phase Structure
1
2
LHC, RHIC
RHIC
3
RHIC, FAIR
RHIC + FAiR
LHC+RHIC
Property of sQGP
RHIC
√sNN ~ 0.05 - 5 TeV
39
11.5
CBM
8
RHIC BES-II
QCD CP and
phase
structure
CP and
Quarkyonic Matter?
√sNN ≤ 8 GeV
For region μB > 500 MeV,
√sNN ≤ 5 GeV, fixedtarget experiments are
much more efficient
√sNN ≤ 20 GeV
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
2/23
QCD Thermodynamics
CBM RHIC LHC
SB Ideal Gas
Zoltan Fodor, Lattice 2007
1) At μB = 0: cross over transition, 150 < Tc < 200 MeV
2) The SB ideal gas limit: T/Tc ~ 107
3) Tini (LHC) ~ 2-3*Tini (RHIC)
4) Thermodynamic evolutions are similar for RHIC and LHC
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
3/23
LHC, RHIC, FAIR
（I）2000 - 2012: RHIC, LHC
1) sQGP: strongly coupled QGP, η/S =>0, ideal fluid.
2) At μB＝0 smooth cross over.
（II）2010 - 2014: RHIC BESI (20≤μB≤420 MeV, 200≥√sNN ≥7.7 GeV)
1) √sNN ≤15 GeV, μB≥300 MeV: Hadronic interactions become dominant.
2) Collectivity and fluctuation results hint phase transition. However, more
data are needed to confirm. RHIC BESII and FAIR CBM.
（III）2018 and beyond:
Collider: RHIC/LHC (√sNN > 200 GeV, μB≤ 20 MeV)
Collider: RHIC BESII (7.7<√sNN < 20 GeV, 420 ≥μB≥300 MeV)
Fixed-target: FAIR CBM (√sNN ≤12 GeV, μB≥ 300 MeV)
1) High luminosity, new detectors
2) Physics focus：sQGP, Cp, Pb and Qm
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
4/23
Bulk Properties at Freeze-out
CBM
STAR Preliminary
Chemical Freeze-out: (GCE)
- RHIC (20 ≤ μB ≤ 420 MeV): small temperature variation
- CBM (400 ≤ μB ≤ 750 MeV): temperature changes dramatically!
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
5/23
Collectivity v2 Measurements
STAR: Phys. Rev. Lett. 110 (2013) 142301
1) Number of constituent quark (NCQ) scaling in v2 =>
partonic collectivity => deconfinement in high-energy
nuclear collisions
2) At √sNN < 11.5 GeV, the universal v2 NCQ scaling is
broken, consistent with hadronic interactions becoming
dominant.
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
6/23
BES v2 and Model Comparison
(a) Hydro + Transport: consistent with baryon data.
[J. Steinheimer, V. Koch, and M. Bleicher PRC86, 44902(13).]
(b) NJL model: Hadron splitting consistent. Sensitive to vector-coupling, CME,
net-baryon density dependent. [J. Xu, et al., arXiv:1308.1753/PRL112.012301]
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
7/23
Chiral Effects
Chiral Vortical Effect
Hot/dense QCD Medium
Parity odd domains form
External
Magnetic Field
Initial Angular
Momentum 
Fluid Vorticity
Chiral magnetic
effect (CME)
(electric charge)
Chiral vortical
effect (CVE)
(baryon charge)
Λ-proton correlation measurement:
1) The opposite baryon number (Λpbar or Λbar-p) correlations (OB)
are similar
2) The same baryon number (Λ-p or
Λbar-pbar) correlations (SB) are
lower than that of the OB, as
expected from the CVE.
D. Kharzeev, D.T. Son, PRL106, 062301(11)
D. Kharzeev. PLB633, 260 (06)
D. Kharzeev, et al. NPA803, 227(08)
SS - OS
Charge Separation wrt Event Plane
STAR: PRL, arXiv: 1404.1433
LPV(CME) disappears: with neutral
hadrons:
LPV(CME) disappears at low energy:
hadronic interactions become dominant
at √sNN ≤ 11.5 GeV
STAR: PRL. 103, 251601(09)
D. Kharzeev. PLB633, 260 (06)
D. Kharzeev, et al. NPA803, 227(08)
Higher Moments
1) Higher moments of conserved quantum numbers:
Q, S, B, in high-energy nuclear collisions
μB = 0
2) Sensitive to critical point (ξ correlation length):
2
3
4
N    2 , N    4.5, N    7
3) Direct comparison with calculations at any order:
B3
S  2 ,
B

4

 2  B2
B
4) Extract susceptibilities and freeze-out
temperature. An independent/important test of
thermal equilibrium in heavy ion collisions.
References:
- STAR: PRL105, 22303(10); ibid, 032302(14)
- M. Stephanov: PRL102, 032301(09) // R.V. Gavai and S. Gupta,
PLB696, 459(11) // F. Karsch et al, PLB695, 136(11) // S.Ejiri et al,
PLB633, 275(06)
- A. Bazavov et al., PRL109, 192302(12) // S. Borsanyi et al., PRL111,
062005(13) // V. Skokov et al., PRC88, 034901(13)
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
10/23
Higher Moments Results
BESII
Net-proton results:
1) All data show deviations below
Poisson for κσ2 at all energies.
Larger deviation at √sNN~20GeV
1) UrQMD model shows monotonic
behavior in the moment products
STAR: PRL112, 32302(14)/arXiv: 1309.5681
Net-charge results:
1) No non-monotonic behavior
2) More affected by the resonance
decays
STAR: arXiv: 1402.1558
P. Garg et al, PLB726, 691(13)
BESII is needed:
Higher statistics needed for
collisions at √sNN < 20 GeV
Comparing to LGT calculations
Tf = 146 ± 6 MeV ,√sNN > 39 GeV
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
11/23
Exploring QCD Phase Structure
1
2
LHC, RHIC
RHIC
3
RHIC, FAIR
RHIC + FAiR
LHC+RHIC
Property of sQGP
RHIC
√sNN ~ 0.05 - 5 TeV
39
11.5
CBM
8
RHIC BES-II
QCD CP and
phase
structure
CP and
Quarkyonic Matter?
√sNN ≤ 8 GeV
For region μB > 500 MeV,
√sNN ≤ 5 GeV, fixedtarget experiments are
much more efficient
√sNN ≤ 20 GeV
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
12/23
STAR: Near Future Plans
2015
2016
HF-I,
(e,μ)
2017
2018
2019
BESII
2020
2021
2022
2023
2024
2025
2026
2027
2028
HF-II*
pA, sPHENIX
HFT’ (mid-y)
Forward upgrade-i
eSTAR
*
1) Mid-rapidity upgrade: ΛC and bottom production at RHIC,
complimentary with LHC HF-jets program
2) Forward upgrade-i: pA, DY measurements & AA physics. ‘Training’ for
the future eA physics program at eRHIC era
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
13/23
Heavy Flavor Energy Loss: Puzzle
W. Horowitz and M. Gyulassy, arXiv:0710.0703
pQCD
pQCD
AdS/CFT
AdS/CFT
1) Both pQCD and AdS/CFT predict ΔE(b) < ΔE(c)!
2) Heavy flavor jet trigger needed (At LO, HF-jets conserved)
3) Without B info, the HF program at RHIC is incomplete!
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
14/23
Efficiency: fast vs. slow HFT
Xin Dong
HFT: ~ 200 μs
HFT’ ~ 30 μs
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
15/23
Faster Pixels
From Leo:
“30 μs integration time
pixel size of 22x66μm2 (7μm single point resolution)
size of ~ 2 x 3 cm
heat dissipation that can be handled by air cooling”
- 6-7 times fast than current HFT pixel.
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
16/23
B  D0 pT Distribution
Guannan Xie
Pythia event:
1) 5B MB 200GeV Au+Au events
2) B-decay D0 spectrum up to pT
~ 10 GeV/c, corresponding to
B-meson pT ~ 17 GeV/c
3) 20 weeks run in 2020-2023
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
17/23
Bottom Decay Kinematics
Xin
J/ψ
Nu Xu
D
Seminar, USTC, Modern Physics Department, October 16, 2014
e
18/23
HFT’ Summary
1) A faster HFT for studying sQGP properties
with heavy quarks including bottom.
- Collect ~10B events
- B (D, J/ψ) spectra and correlation functions
2) Cost effective. Technologies/team are in
hand (… IPHC, CCNU, LBL, UIC).
3) STAR needs it for its AA, pA and pp physics
program. Complimentary to LHC HF and
sPHENIX jet programs during 2020-2024.
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
19/23
Baryon Density Peaks at ~ √sNN = 8 GeV
1304.2969
High
Baryon
Density
CP
NICA (4 - 11)
????
2019
CBM (2 - 5 - 8)
BESII (8 - 20)
2018/19
Collision Energy √sNN (GeV)
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
20/23
The CBM Experiment
Target
STS
RICH/TRD
TOF
EMCal
ZDC
FAIR: the highest intensity accelerator complex in the 21st century
Precision measurements at high baryon density region for:
(i) dileptons (e, μ); (ii) high order baryon correlations; (iii) flavor productions (s, c)
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
21/23
Exploring QCD Phase Structure
1
2
LHC, RHIC
RHIC
3
RHIC, FAIR
LHC+RHIC
RHIC + FAiR
Property of sQGP
√sNN ~ 0.05 - 5 TeV
RHIC
39
11.5
CBM
8
RHIC BESII
CP and
Quarkyonic Matter?
√sNN ≤ 8 GeV
For region μB > 500 MeV,
√sNN ≤ 5 GeV, fixedtarget experiments are
much more efficient
QCD CP and
phase
structure
√sNN ≤ 20 GeV
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
22/23
The Future HI Programs at RHIC
 HFT’: Complete the heavy flavor
physics programs at RHIC and LHC
 Properties of sQGP
 CBM: Complete the beam energy
scan program at RHIC  QCD
Phase Boundary and Critical Point
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
23/23
Energy Dependence of Di-electrons
Bulk-penetrating probe:
STAR Preliminary
200GeV
62.4GeV
39GeV
27GeV
1) Mee ≤ 1GeV/c2: In-medium
broadened ρ, model results*
are consistent with exp. data.
At 200GeV, the enhancement
is in the order of 1.77±0.11
±0.24±0.33 within
0.3<Mee<0.7GeV/c2) (* driven
by the baryon density in the
medium)
2) 1≤Mee ≤ 3GeV/c2: Thermal
radiation: exp(-Mee/T)?
HFT: Charm contributions.
3) High statistics data are
needed, BESII!
19.6GeV
- STAR: (200GeV data) sub. to PRL. 1312.7397
- R. Rapp: PoS CPOD13, 008(2013)
- O. Linnyk et al, PRC85, 024910(12)
Nu Xu
Seminar, USTC, Modern Physics Department, October 16, 2014
24/23