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Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department of Engineering Physics Tsinghua University

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Page 1: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strangeness Production and Thermal Statistical Model

Huan Zhong Huang

Department of Physics and Astronomy

University of California, Los Angeles

Department of Engineering Physics

Tsinghua University

Page 2: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strange Particle Discovery

1935 Yukawa: meson exchange model for nuclear interactionElectromagnetic interaction – photons infinite range -- photon masslessNuclear Interaction (Strong Force) – mesons Range (Rutherford Scattering) ~ 1-2 fmUncertainty principle

E t ~ cmeson mass ~ 100-200 MeV/c2

1937 Cloud Chamber cosmic ray eventsmass 106 MeV/c2

not the Yukawa meson, muon1947 C. Powell, C. Lattes and G. Occhialini

photographic plates at a mountain topm ~ 140 MeV/c2

+v

Page 3: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Particle Discovery

neutral pion 0 1950 accelerator experiment1947 G.D. Rochester and C.C. Butler

v – decay vertex – discovery

V0

V+

m ~ 1000 me

Page 4: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Kaon versus pion

du dduu 2

1Pions: ud

Neutron pions – the anti-particle is itself !! not true to neutral K0

K0 and K0 are different particles !

u, d quark masses 5-10 MeV/c2

strange quark mass ~ 150 MeV/c2

SU(3) representation for u,d,s quarks, light quarks

Page 5: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strangeness Quark Mass Important!

Page 6: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

SU(3) Representation of Particles

Page 7: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strangeness Conservation

222 pNN mmEms

In Strong Interaction: strange quarks can only be produced in pairs !

Associated Production:p + N NK+

Pair Production:p + N pNK+K-

Threshold in fixed target: s = (E+mN)2 – p2

KKNppNNth

KNpNNth

mmmmmmmE

mmmmmmE

22

22

2

2

Associated Production More Effective (lower Threshold) @ low beam energies

Page 8: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strange Baryons Sensitive to Bulk Partonic Matter

Tc~ ms

Page 9: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

The Melting of Quarks and Gluons-- Quark-Gluon Plasma --

Matter Compression: Vacuum Heating:

High Baryon Density-- low energy heavy ion collisions-- neutron starquark star

High Temperature Vacuum -- high energy heavy ion collisions -- the Big Bang

Deconfinement

Page 10: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

High Baryon Density at the AGS Si+Si 14.6 A GeV

Si+Au14.6 A GeV

Au+Au11.7 A GeV

ARCYang Pang

Page 11: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Systematic Kaon Measurement

NPart

NPart

NK-

NK+

NK+

/NK-

E802/E859/E866

Au+Au

Si+Au

Page 12: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Measurement

~ 17 sper centralAu+Au @ AGS

Page 13: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Large to p Ratio

Anti-hyperon absorption in dense medium?

Dynamical conversion of anti-protons to anti-Lambda?

Similar results from E917.

E864/E878

Page 14: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strangeness is ‘enhanced’ at SPS

No of Wounded Nucleons

YieldN-wound

Baryon and anti-baryons are both enhanced, but by different amount !

WA97/NA57 and NA49 Consistent Results

Page 15: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

NPART or No Wounded Nucleons Nucleons wounded once, twice or n times are different !

NA49 Data

NPart

Page 16: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Beam-Target Fragmentation Important

E910 p+A @ AGS

Strange Baryon Production Increases with Number of Collisions !

NA49 results lead to the same conclusion for p+A collisions ! Both fragmentation and pair production increase @SPS !!

Page 17: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Proton Fragmentation and Hyperon Production

E941@AGS data Baryons Very Brittle!

pAup+XpAun+X EQUAL

Page 18: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Energy Dependence of Strangeness Production

Page 19: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Mid-rapidity Ratio versus CM energy

Page 20: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

4 Integrated Ratio versus Energy

1/4NNs

Page 21: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strange Quark Production

Page 22: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Quark to Pion Ratio

Kink or Not ?

Page 23: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

The to Ratio

@mid-rapidityPb+Pb @SPSMany more sThan s !!

Page 24: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Scenarios of Baryon Number Transport

Direct Transport Through Gluon Junctions …

X)

Indirect Transport Through Pair Production Modified by Baryon Chemical Potential …

and K

and K

and p / n ) K

Net Baryon Density Increases the Associated Production and Transfers net baryon number to multiply-strange baryons !

Event-by-Event STAR Hyperon Correlations Doable with STAR TOF and SVT Upgrade !

Page 25: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Multi-Strange Baryon Spectrum Shape

Page 26: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Too Many Baryons at Intermediate pT

Au+Au 0-10%

p+p

Page 27: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Cannot Simply Blame Gluon Fragmentation !

Glu

on/Q

uar

k

~10-20% difference in baryon production between gluon and quark jets

(SLD)

Page 28: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

1/3

String Fragmentations Suppress Strange Baryons

Standard string fragmentation for baryon formation through diquark tunneling out of string potential: dependence m(ud-1) = 0.49 GeV m(ud-0) = 0.42 GeV predicts =0.35.

If , STAR data would imply , very unlikely !

RQMD

Diquark fragmentation scheme for multi-strange baryon production in A+A collisions – Ruled Out ?!

See M.Bleicher et al, PRL 88, 202501 (2002) on Discussion,

/2me

Page 29: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Multi-parton Dynamics and Baryon Production

q

qq

q

q q

Baryon Anti-Baryon

Baryon (Hyperon) Production may be Enhanced by Multi-parton Dynamics:

Gluon Junction Mechanism -- (Kharzeev, Gyulassy and Vance ….)

Quark Coalescence – (ALCOR-J.Zimanyi et al, AMPT-Lin et al,Molnar+Voloshin …..)

Quark Recombination – (R.J. Fries et al….)

Key Measurement: 0/ Ratio 0.35 String Fragmentation 0.65-0.75 Thermal Statistical 1 Gluon Junction/Coalescence

Physics Implication of multi-parton dynamics on v2 and RAA

Junction

Page 30: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Thermal Statistical Model

ch

i

ch

iT

n

T

n

nsi

chi T

mK

T

meeg

Tn ch

ss

ch

qq

s2

2

2

3

2

ezdzn

nzK

n

zn

n

n

21

221

)!2(

!2)(

Particle Density

Modified Bessel Function

Must Include all particles including resonances !!Physical meaning of s – phase space suppresion factor

Page 31: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Thermal Statistical Model

62.4 GeV 200 GeV

Tch (MeV) 160-170 160-170

B (MeV) 70 20

s (MeV) 0 0

200 GeV

Page 32: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strangeness Enhancement and s

Page 33: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Chemical Freeze-out @ Phase Boundary

Page 34: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Misleadingly Appealing and Beautiful

Becattini: T=170, s=1

PBM (PLB518,(2000)41) predicts y=0ratios almost exactlyK-/K+=exp(2ms/T)(pbar/p)1/3

K- /K+=(pbar/p)1/4 is a fit to the data points

Agreement Appealing !Conceptually ?Equalibrium in local spatial region --- ButMeasurement in rapidity bin -- Fireball emission region in pT-y.I. Bearden, BRAHMS

Page 35: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Kinetic and Chemical Freezeout

Page 36: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

R

s

R

s

Blast Wave

tanh 1 rE.Schnedermann et al, PRC48 (1993) 2462

dn

mT dmT r dr mT K1

mT coshT

0

R

I0pT sinh T

where:

r =s (r/R)n

STAR Preliminary

Page 37: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Blast Wave Fit

Parameters: Freeze-out T; Transverse Flow Velocity T

Page 38: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Different Freeze-out Conditions

Multi-strange Baryons freeze-out early: high T and small v

Physical origin for non-zero v?

/

p/K/

Page 39: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Have We Observed This ?

Page 40: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strange Baryon Physics1 is special –

@AGS Quark level clustering or coalescence@SPS Sensitive to dynamics of baryon number transport@RHIC v2 and transverse radial flow reflects partonic

collectivityThere may be a special di-Omega state -]

2) Baryons, Strange Hyperons, --Multi-parton Dynamics: Gluon Junctions, Quark Coalescence

Quark Recombinations ……

We began to investigate quantitatively features which may be related to anisotropy and hadronization properties

of bulk partonic matter !

3) Strange Baryons and Heavy Quarks Are Sensitive Probes of Bulk Properties of Matter at RHIC ! STAR’s future Barrel TOF and MicroVertex detector upgrade will

greatly enhance STAR’s physics capability on these topics.

Page 41: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

END of Talk

Page 42: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department
Page 43: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Statistical QCDStatistical QCD

42

228

72

30TQED

42

33228

783

30TQCD

photon spin electrons spin

gluon spin, color quarks spin, color, flavor

Energy density reflects the information on what the matter is made of !

Page 44: Strangeness Production and Thermal Statistical Model Huan Zhong Huang Department of Physics and Astronomy University of California, Los Angeles Department

Strange Baryons and Dynamics of Early Stages

Precision Measurement of and Spectra Shape at the Low pT Region is Needed !!

Javier Castillo


Huan CA Bamba

Strangeness Measurements in BRAHMS

Strangeness measurements with the Experiment

Parton Model & Parton Dynamics Huan Z Huang Department of Physics and Astronomy University of California, Los Angeles Department of Engineering Physics

Tap Huan Fttx

Strangeness in the Nucleon

Chal Huan CA

System-size dependence of strangeness production, canonical strangeness suppression, and percolation Claudia Höhne, GSI Darmstadt

Strangeness nuclear physics.pdf

STRANGENESS IN QUARK MATTER 2013

Tap huan 12.8

Huan Capet i

Strangeness Experimental Techniques

Strangeness and QGP

Huan Chaco

Discovery of Quark-Gluon Plasma: Strangeness Diaries€¦ · Strangeness Diaries Johann Rafelski1,2;a 1 CERN-TH, 1211 Geneva 23, Switzerland 2 Department of Physics, The University

Strangeness in Collisions Workshop “Strangeness in p+p: Data vs Models”

Strangeness Production at RHIC

Strangeness Workshop Warszawa 2016

STRANGENESS NUCLEAR PHYSICS

Strangeness analysis in ALICE

Strangeness Production @ COSY

Strangeness Production at SIS Energies SQM 2007 International Conference on Strangeness in Quark Matter Xavier Lopez

STAR Time-Projection Chamber Huan Zhong Huang Department of Engineering Physics Tsinghua University & Department of Physics and Astronomy University of

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