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Beam energy dependence of 𝑑 and �� production in Au + Au collisions at RHIC
Ning YuCentral China Normal Universityfor the STAR Collaboration
2017/2/7 17:10-17:30
Outline
✯ Introduction
✯ STAR Experiment
✯ Results and Discussions
✯ Summary
Ning Yu, Quark Matter 2017@Chicago 1/20
2017/2/7 17:10-17:30
QCD Phase DiagramLHC,RHIC
Future FAIR Experiment
K. Fukushima and C. SasakiProg. Part. Nucl. Phys, 72, (2013) 99
✯ High temperature: QGP properties✯ High baryon density:
ü Critical point and phase boundaryü Possible new phase structure : quarkyonic matter
Phase transition
Correlations of nucleons
Light nuclei
Ning Yu, Quark Matter 2017@Chicago 2/20
2017/2/7 17:10-17:30
Light Nuclei Formation in HI Collisions✯ Light (anti)nuclei with small binding energy (𝜀), such as 𝑑 and �� with binding
energy 𝜀 = 2.2 MeV, are formed via final-state coalescence
𝐸(𝑑)𝑁(𝑑)𝑝(
= 𝐵( 𝐸-𝑑)𝑁-𝑑)𝑝-
.
𝐸/𝑑)𝑁/𝑑)𝑝/
(0.
≈ 𝐵( 𝐸-𝑑)𝑁-𝑑)𝑝-
(
, 𝑝(= 𝐴𝑝-
✯ In thermodynamics, 𝐵( is related to the nucleon freeze-out correlation volume 𝑉6or baryon density
𝐵( ∝ 𝑉680(, 𝐵9 =6𝜋)𝑅/-𝑚>
𝑚-9𝑉6
, 𝑅/- =𝑁/𝑁-
✯ Light nuclei may serve as probes of space-momentum density and correlation of nucleons at freeze-out. We will focus on 𝑑 (��) in this talk.
László P. Csernai, Joseph I. Kapusta Phys. Reps, 131,223(1986)B. Monreal, et. al. PRC60,031901(1999), PRC60,051902(1999)
Ning Yu, Quark Matter 2017@Chicago 3/20
2017/2/7 17:10-17:30
Energy Dependence of 𝑩𝑨Most Central
✯ The size of the fireball increase from low to high collision energy, 𝐵9 decrease with energy
✯ The behavior of 𝐵9 is different at high energy
✯ Is there any structure in the
energy dependence of 𝑩𝟐, from high energy to low energy ?
✯ Is there any centrality dependence of 𝑩𝟐?
✯ Is there any difference of 𝑩𝟐between deuteron and anti-
deuteron?PHENIX, PRL. 94, 122302 (2005).
Ning Yu, Quark Matter 2017@Chicago 4/20
1 10 100Collision Energy 𝒔𝑵𝑵� (GeV)
2017/2/7 17:10-17:30
RHIC Beam Energy Scan
𝒔𝐍𝐍� (GeV) 7.7 11.5 14.5 19.6 27 39 62.4 200Neve(M) 4 11 27 40 71 133 67 480𝝁𝑩(MeV) 420 315 260 205 155 115 72 20
✯ BES-I Au+Au collisions at 𝑠HH� = 7.7, 11.5, 14.5, 19.6, 27, 39 and 62.4 GeVü Search for conjectured QCD critical
point ü Search for the first order phase
transitionü Search for the onset of key QGP
signatures
STAR Collaboration, arXiv:1007.2613
J. Cleymans, H. Oeschler, K. Redlich, and S. WheatonPRC 73,034905 (2006)
Ning Yu, Quark Matter 2017@Chicago 5/20
2017/2/7 17:10-17:30
Solenoidal Tracker At RHICTime Projection Chamber(TPC)
ü Charged Particle Tracking
ü Momentum reconstruction
ü Particle identification from ionization
energy loss (dE/dx)
ü Pseudorapidity coverage |η| < 1.0
Time Of Flight (TOF)
ü Particle identification m2
ü Pseudorapidity coverage |η| < 0.9
Ning Yu, Quark Matter 2017@Chicago 6/20
2017/2/7 17:10-17:30
Particle Identification
Z (d) 0.4− 0.3− 0.2− 0.1− 0 0.1 0.2 0.3 0.4
Cou
nts
0
0.5
1
1.5
2
310×
DATASign.+Backgr.Sign.Backgr.
deuteron 39 GeV 0-5% < 0.8 GeV/c
T0.6 < p
)4/c2 (GeV2m2.5 3 3.5 4 4.5
Cou
nts
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
310×
DATASign.+Backgr.Sign.Backgr.
deuteron 39 GeV 0-5% < 2.8 GeV/c
T2.4 < p
𝑧> = log𝑑𝐸 𝑑𝑥⁄𝑑𝐸 𝑑𝑥⁄ >
OO
𝑚9 = 𝑝9𝑐9𝑡9
𝐿9 − 1
BB : Bethe-BlochH. Bichsel, Nucl. Instrum. Meth. A 562, 154 (2006).
Ning Yu, Quark Matter 2017@Chicago 7/20
2017/2/7 17:10-17:30
Efficiency and Acceptance
𝜀UVW 𝑝X = 𝑎Zexp −𝑎8𝑝X
^_+ 𝑝𝑜𝑙(2)
𝜀Ude 𝑝X = 𝑎Zexp −𝑎8𝑝X
^_
𝜀Ude 𝑝X =ThenumberofTOFMatchedTracks
ThenumberofTPCTracks
Ning Yu, Quark Matter 2017@Chicago 8/20
2017/2/7 17:10-17:30
Corrections✯ Energy Loss
✯ Background in 𝑑 analysis
𝑓 𝑝X = 𝐴 + 𝐵 1 +𝐶𝑝X9
{
- No centrality dependence of energy loss- Energy loss of 𝑑 and �� are the same- The energy loss for all the collision energy are the
same except 14.5 GeV (different material budget)
Ning Yu, Quark Matter 2017@Chicago 9/20
2017/2/7 17:10-17:30
Deuteron Spectra✯ Mid-rapidity ( 𝑦 ≤ 0.3) transverse
momentum distribution of 𝑑 from
Au+Au Collision
✯ Dash line: blast-wave function fits1 2 3 4
5
4
3
2
1
111.5 GeV
1 2 3 4
5
4
3
2
1
114.5 GeV
1 2 3 4
6−10
5−10
4−10
3−10
2−10
1−10
1
19.6 GeV
1 2 3 4
6
5
4
3
2
1
1
27 GeV
1 2 3 4
6
5
4
3
2
1
1
39 GeV
1 2 3 4
6−
10
5−
10
4−10
3−
10
2−10
1−10 62.4 GeV
1 2 3 4
6
5
4
3
2
1 200 GeV
1 2 3 4
6
5
4
3
2
1−
4 2× 0-10%
3 2×10-20%
2 2×20-40%
1 2×40-60%
0 2×60-80%
(GeV/c)T
Transverse Momentum p
Deuteron from Au+Au Collision
)2
/Ge
V2
dy)
(c
TN
/(d
p2
)dT
pπ
1/(
2
1 2 3 4
5−
10
4−10
3−
10
2−10
1−10
17.7 GeV
STAR Preliminary
d9𝑁𝑚X𝑑𝑚X
∝ � 𝑟d𝑟𝑚X𝐼Z𝑝Xsinh𝜌
𝑇 𝐾8𝑚Xcosh𝜌
𝑇
�
Z
Ning Yu, Quark Matter 2017@Chicago 10/20
2017/2/7 17:10-17:30
Anti-Deuteron Spectra
1 2 3 4
6
5
4
3
11.5 GeV
1 2 3 4
6
5
4
3
14.5 GeV
1 2 3 46−10
5−10
4−10
3−10
2−10 19.6 GeV
1 2 3 46
5
4
3
2
27 GeV
1 2 3 46
5
4
3
2
39 GeV
1 2 3 4
6−
10
5−
10
4−10
3−
10
2−10
1−10
62.4 GeV
1 2 3 4
6
5
4
3
2
1
200 GeV
1 2 3 4
6
5
4
3
2
1−
4 2× 0-10%
3 2×10-20%
2 2×20-40%
1 2×40-60%
0 2×60-80%
(GeV/c)T
Transverse Momentum p
Anti-Deuteron from Au+Au Collision
)2
/Ge
V2
dy)
(c
TN
/(d
p2
)dT
pπ
1/(
2
1 2 3 4
6−
10
5−
10
4−10
3−
10
d9𝑁𝑚X𝑑𝑚X
∝ � 𝑟d𝑟𝑚X𝐼Z𝑝Xsinh𝜌
𝑇 𝐾8𝑚Xcosh𝜌
𝑇
�
Z
STAR Preliminary
✯ Mid-rapidity ( 𝑦 ≤ 0.3) transverse
momentum distribution of �� from
Au+Au Collision
✯ Dash line: blast-wave function fits
Ning Yu, Quark Matter 2017@Chicago 11/20
2017/2/7 17:10-17:30
𝒑𝑻 and 𝑻𝒌𝒊𝒏, 𝜷
⟩ Part
N⟨100 200 300
( G
eV/c
)⟩
T p⟨
1
1.5
219.6 GeV 27 GeV 39 GeV62.4 GeV 200 GeV
Au+Au Anti-Deuteron
⟩ Part
N⟨100 200 300
( G
eV/c
)⟩
T p⟨
1
1.5
27.7 GeV 11.5 GeV 14.5 GeV 19.6 GeV27 GeV 39 GeV 62.4 GeV 200 GeV
Au+Au Deuteron
STAR Preliminary STAR Preliminary
39 GeV 𝑑 �� 𝜋, 𝐾, 𝑝∗
Cent. 𝑻𝒌𝒊𝒏(MeV) 𝜷(c) 𝑝X (GeV/c) 𝑝X (GeV/c) 𝑻𝒌𝒊𝒏(MeV) 𝜷(c) 𝑝X (GeV/c)0-10% 99±12 0.45±0.02 1.35±0.09 1.39±0.09 118±11 0.48±0.04 0.85±0.0510-20% 110±14 0.43±0.02 1.32±0.09 1.35±0.05 120±11 0.46±0.03 0.83±0.0520-40% 135±23 0.39±0.02 1.23±0.08 1.23±0.08 126±11 0.41±0.03 0.79±0.05
✯ 𝒑𝑻 decrease fromcentral to peripheralcollision
✯ 𝒑𝑻 of 𝑑 and 𝑑 areconsistent within error
✯ B.W. can describe both𝑑 and 𝜋, 𝐾, 𝑝 withsimilar parameters
∗ STAR Collaboration, arXiv:1701.07065 (submitted to PRC)
Ning Yu, Quark Matter 2017@Chicago 12/20
2017/2/7 17:10-17:30
Integral Yield 𝒅𝑵 𝒅𝒚⁄
✯ 𝑑𝑁 𝑑 /𝑑𝑦 is smaller at higher energy: baryon stopping✯ 𝑑𝑁(𝑑)/𝑑𝑦 increases with increasing energy: baryon pair production✯ 𝑁���� scaled 𝑑𝑁/𝑑𝑦 for 𝑑 show weak centrality dependence, for 𝑑
increase slightly from peripheral to central collision
⟩ Part
N⟨100 200 300
]⟩ P
art
N⟨×
dN
/dy/[
0.5
6−10
5−10
4−10
3−10
11.5 GeV 14.5 GeV 19.6 GeV 27 GeV39 GeV 62.4 GeV 200 GeV
Au+Au Anti-Deuteron
⟩ Part
N⟨100 200 300
]⟩ P
art
N⟨×
dN
/dy/[
0.5
3−10
2−10
7.7 GeV 11.5 GeV 14.5 GeV 19.6 GeV
27 GeV 39 GeV 62.4 GeV 200 GeV
Au+Au Deuteron
STAR Preliminary STAR Preliminary
Ning Yu, Quark Matter 2017@Chicago 13/20
2017/2/7 17:10-17:30
Antiparticle to Particle Ratios
✯ 𝑁 �� /𝑁 𝑑 ratio decreases as a function of collision centrality✯ 𝑁 �� /𝑁 𝑑 ratio decreases with decreasing energy
⟩ Part N⟨100 200 300
)/N(d
)d
N(
0
0.2
0.4
0.6
0.8 200 GeV 2×39 GeV
4×19.6 GeV PHENIX 200 GeV
STAR Preliminary
PHENIX, PRL. 94, 122302 (2005).
Ning Yu, Quark Matter 2017@Chicago 14/20
2017/2/7 17:10-17:30
𝑵(𝒅)/𝑵(𝒑) Ratio vs. Energy
The lines are from thermal model predictionA. Andronic, P. Braun-Munzinger, J. Stachel, H. Stocker, PLB697 (2011)203
(GeV)NNs10 210 310
Parti
cle
Rat
io
4−10
3−10
2−10
1−10
1STAR 0-10% d/p
p/dSTAR 0-10% SIS d/pEOS802 d/pNA49 d/pPHENIX d/p
p/dPHENIX ALICE d/p
Thermal Prediction
5 MeV±T = 163
✯ The N(𝑑)/𝑁(𝑝) ratios by thermal model prediction are consistentwith the data from SIS energies up to LHC
✯ A temperature of 𝑇 = 163 ± 5 MeV can be extracted from 𝑁(𝑑)/𝑁(𝑝)and 𝑁(��)/𝑁(��)
𝑁(𝑑)𝑁(𝑝) ~
𝐾9 𝑚> 𝑇⁄𝐾9 𝑚- 𝑇⁄
𝑒��X
𝑁(��)𝑁(��) ~
𝐾9 𝑚> 𝑇⁄𝐾9 𝑚- 𝑇⁄
𝑒0��X
STAR Preliminary
Ning Yu, Quark Matter 2017@Chicago 15/20
2017/2/7 17:10-17:30
𝒅/𝒑𝟐 and 𝒅�/𝒑�𝟐 Ratios✯ In thermal model with GCE (grand canonical
ensemble), 𝑑 𝑝9⁄ and �� ��9⁄ should be the same if iso-spin effect can be neglected
𝜇 𝑇 =
12 ln
�� ��9⁄𝑑 𝑝9⁄
✯ The 𝜇 /𝑇 can also be obtained by 𝜇 𝑇 =
12 ln
𝜋¡
𝜋0
The results are close to zero implying smalliso-spin effect
10 210
2d/p
0.2
0.4
0.6
0.8
3−10×
2d/p2
p/d
p err.
err.p
Au+Au 0-10%
(GeV)NNs10 210
/ T
Qµ 0.5−
0
2BES d/p-
π/+πBES -
π/+πNA49 Initial Iso-spin
STAR Preliminary
NA49, PRC 94, 044906 (2016)
Ning Yu, Quark Matter 2017@Chicago 16/20
2017/2/7 17:10-17:30
𝑩𝟐 v.s. 𝒎𝑻 and Collision Centrality
✯ The values of 𝐵9 increase as a function of 𝑚Xand decrease with collision centrality : collective expansion
✯ 𝐵9 𝑑 are smaller than that of 𝐵9 𝑑 , anti−baryon freeze out at a larger source
𝐵9 = 𝑎 £ exp 𝑏 𝑚X − 𝑚
NA44, EPJ C. 23, 237 (2002)
)2 - m (GeV/cTm0.5 1 1.5
)3/c2
(GeV
2B
1
2
3
4
3−10×
(d) 0-10%2B(d) 10-20%2B(d) 20-40%2B(d) 40-60%2B
)2 - m (GeV/cTm0.5 1 1.5
)3/c2
(GeV
2B
) 0-10%d(2B) 10-20%d(2B) 20-40%d(2B) 40-60%d(2B
Au+Au 39 GeV
STAR Preliminary
Ning Yu, Quark Matter 2017@Chicago 17/20
(GeV)NNs4 5 6 7 8 10 20 30 40 100 200
)3/c2
(GeV
2B
3−10
E864(d) Au+PbE866(d) Au+AuE877(d) Au+AuNA49(d) Pb+PbPHENIX(d) Au+Au
) Au+AudSTAR() Au+AudPHENIX(
/ A = 0.65 GeV/cT
pSTAR 0-10%(d) Au+Au
) Au+AudSTAR 0-10%(
Average of p+p and p+A
Central CollisionSTAR Preliminary
2017/2/7 17:10-17:30
Coalescence Parameters v.s. Collision Energy
✯ 𝐵9 decrease with collision energy. A minimum around sHH� = 20 GeV :change of EOS?!
✯ 𝐵9 𝑑 values are systematically lower than that of 𝐵9(𝑑) implying emitted source of anti-baryons is larger than those of baryons
arXiv:1410.2559
∝ ∆𝝉 ∝ 𝒄𝒔
Ning Yu, Quark Matter 2017@Chicago 18/20
2017/2/7 17:10-17:30
Discussion✯ Is there any structure in energy
dependence of 𝐵9, from high
energy to low energy ? (BES: Yes)
✯ Is there any centrality dependence
of 𝐵9? (Yes)
✯ Is there any difference of 𝐵9between deuteron and anti-
deuteron? (Yes) (GeV)NNs4 5 6 7 8 10 20 30 40 100 200
)3/c2
(GeV
2B
3−10
E864(d) Au+PbE866(d) Au+AuE877(d) Au+AuNA49(d) Pb+PbPHENIX(d) Au+Au
) Au+AudSTAR() Au+AudPHENIX(
/ A = 0.65 GeV/cT
pSTAR 0-10%(d) Au+Au
) Au+AudSTAR 0-10%(
Average of p+p and p+A
Central CollisionSTAR Preliminary
Ning Yu, Quark Matter 2017@Chicago 19/20
2017/2/7 17:10-17:30
Summary✯ STAR systematic results of 𝑑(��) production (𝑑𝑁/𝑑𝑦, 𝑝𝑇 ) from Au + Au collisions
at 𝒔𝐍𝐍� = 7.7, 11.5, 14.5, 19.6, 27, 39, 62.4 and 200 GeV
✯ Coalescence parameter𝐵9for𝑑 and �� are extracted. 𝐵9(𝑑) and 𝐵9(��) are found to
be different in the most central collisions
✯ Similar to the 𝜋 HBT and net-proton high moment, around sHH� = 20 GeV, 𝐵9reaches a minimum implying EOS changes around the energy
✯ High statistics data are needed for future studies, especially at the high net-baryon
density, i.e., low collision energy region
Ning Yu, Quark Matter 2017@Chicago 20/20
Thank you
2017/2/7 17:10-17:30 Ning Yu, Quark Matter 2017@Chicago 21/20