V. Greco Università di Catania, Italy - PowerPoint Presentation

Slide1

V. GrecoUniversità di Catania, ItalyINFN-LNS

Modelli

Idrodinamici e di Ricombinazione con pT spettri e v2 at LHC

?

V.

Minissale

F.

Scardina

S.

Plumari

Slide2

Brief Introduction to basic idea of coalescence

Agreement with main pattern Baryon vs Meson How the model is set-up to make prediction RHIC LHC (success in predicting pT spectra and ration p,K,p, L…)Outline

Some Features and some Legends

Radial and Elliptic

Flow in Coalescence

mass,

n

q

meson vs baryon, hydro radial flow Is the QuarkNumberScaling

a prediction of Coalescence? Why QNS is expected to be violated

Slide3

In

pp

-> p/

p ~ 0.3 - fragmentation Baryon/Mesons

Elliptic flow v

2B

> v

2M

Au+Au

p+p

Jet quenching should affect both

At

p

T

> 2

GeV

v2 for Baryon=Mesons in both

- hydrodynamics - jet fragmentation

Slide4

Hadronization in Heavy-Ion Collisions

Initial state: no partons in the vacuum

but a thermal ensemble of partonsNo direct QCD

factorization scale for the bulk: dynamics much less violent (t ~ 4 fm/c)

Parton

spectrum

H

Baryon

Meson

Coal.

Fragmentation

V. Greco et al.

/

R.J. Fries et al., PRL 90

(03

)

Fragmentation:

energy

to

create quarks from vacuum

hadrons from higher

p

T

partons

are already there

$ to be close in phase space $

p

h

= n

p

T

,

, n = 2

,

3

baryons from

lower

p

T

(denser)

Coalescence:

ReCo

pushes

out soft

physics

by

factors

x2

and

x3 !

p

1

+p

2

=

p

h

p

h

= z p,

z≈0.5

Slide5

Phase-Space

Coalescence (GKL

)

fq invariant parton

distribution function

thermal with radial flow (b

=0.5r/R) quenched minijets (p

T> 2 GeV)

f

H

hadron Wigner function

D

x

=

1/Dp (real free parameter different)

npQCD

also encoded in quark masses,

mq=0.3 GeV, m

s=0.480 GeV

gH statistical factor color-spin-isospin

gg

->

qq

,

suppressed

by

mass

3D Geometry and radial flow

First higher states (resonances) suppressed by the statistical

exp

[-(E*-E)/T]

quenched

soft

hard

Parton spectrum

Slide6

dE

T

/dy ~ 740

GeV  2100 GeVdNch/dy ≈ 670  1600 Tc ~

160 MeV

Hadronization

occurs ate ~ 0.7

GeV

/fm3

Bulk matter consistent with hydro, experiments,

lQCDOnly parameter wave function width

Dp kept

the same at RHIC and LHC!

Parton

bulk matter

parameters

Experiments

ExperimentslQCD T

c

RHIC

 LHC

b

(r)=

b

0

r/R

b

0

= 0.38



0.6

Radial transverse flow

Lifetime and Volume implied

~ 4.5

fm

/c

 8

fm

/c

V

~ 1100 fm

3

 2500 fm

3

In agreement with HBT evolution

V.

Minissale

et al.,

arXiv

:1502.06213

Slide7

Meson & Baryon

Spectra - RHIC

GKL

ReCo dominates up to 3.5 (pion)-5(proton) GeV/c; Fragmentation + energy

loss

takes over above

.

Au+Au@200AGeV, 0-10%antiproton

pion

Slide8

Meson & Baryon

Spectra - RHIC

GKL

Au+Au@200AGeV, 0-10%LambdaKaonResonance decays includedReCo dominates

up

to

4 (kaons

)-5.8(Lambda) GeV/c

;

Slide9

Meson & Baryon

Spectra - LHC

ReCo

dominates up to 4 (pions)-6(Lambda) GeV/c; Fragmentation + energy loss takes over above.

At LHC coalescence extends to larger

p

T: 0.5 GeV (pions) – 1.0 GeV

(protons) Pb+Pb@2.76ATeV, 0-10%

protonpion

V.

Minissale et al.,

arXiv:1502.06213

Slide10

Meson & Baryon

Spectra - LHC

ReCo

dominates up to 4.2 (kaon)-6.5(Lambda) GeV/c; Fragmentation + energy loss takes over above.

Pb+Pb@2.76ATeV, 0-10%

Lambda

kaon

Slide11

Baryon/Meson

ratio - LHC

Pb+Pb@2.76ATeV, 0-10%

Height and pT position of the peak well described.Lack of fragmentation at pT ≈ 6 GeV (seen also in pp with AKK)Soft-minijet coalesc. contribution around and above the peak (similar to EPOS)Only colaescence would give higher peak shifted in pTWithout radial flow … ( pp collisions but not exactly)V. Minissale et al., arXiv:1502.06213

Slide12

Hydrodynamical radial flow or nq recomb.?

* It is

clear that w/o

radial flow recomb. does not work! * Is Coal. Necessary? (M. Floris et al.) * What’s the approach working in the range pT≈ 2-10

GeV?

Mass

or quark number? F(1020) vs

p(938)

Slide13

* What’s the approach working in the range pT≈ 2-10 GeV

?* Is the

coalescence necessary?EPOS= (half)-viscous-hydro+ soft-jet recombination

K. Werner, PRL109 (2012) 102301It is not that different.E’ solo che non c’e’ una formulaper capire cosa fanno i vari parametri- p/

p ?

- v2

of L and K ?- Also pT

spectra check

Slide14

Taos, 19-24 July 2004

Hot

Quarks

2004

Slide15

Missing fragmentationContribution usually half of the yield at pT ≈4 GeVSoft partsame slope f and pPrediction for

f at LHC - Preliminary

We do not have the

fragm. function for f

It is clear that coalescencepredict a similar slope for

f and p

That is the difference

in the radial flow between1h*1000 MeV,2q*500 MeV3q*330 MeV

in the radial flow effect?p/

f

Slide16

The other main feature of coalescence:Impact on the elliptic flow

Slide17

v2 for baryon is

larger and

saturates at higher p

Tv2q fitted from v2p

GKL, PRC68(03)

Coalescence and Elliptic Flow

Enhancement of v

2

At

higher

p

T

v

2 for Baryon=Mesons in both - hydrodynamics

- jet fragmentationAu+Au@200AGeV

PHENIX

Slide18

Quark Number Scaling?!

It is related with energy conservation

QNS

scaling

Enhancement of v

2

L

p

Slide19

Slide20

Quark Number Scaling?

Enhancement of v

2

Coalescence scaling

Assumptions

:

1D collinear coalescence

Wave function is a delta function : P

T

=

p

T

/2+p

T

/2 =

p

T

/3+p

T

/3+p

T

/3Direct production: no feed-down from resonance decayNo space-momentum correlation (-> no radial flow)No contribution from fragmentation

vn=0 for n>2 , not true especially at LHC and with the e-b-e measurements

Slide21

Resonances & v

2 scaling

K,

L, p … v2 not affected by resonances!p coal. moved towards data Greco-Ko, PRC 70 (03)

w.f. + resonance decay

K & p

*

p

from

Slide22

Role of finite mass - 3D

Importance

of 3D phase-space lowering pT At low pT scaling can be largely brokenbut dumped by the shape of v2(pT) Lower mass lead to larger breakingof the scaling

due to coalescence

between quark with large

q=p1-p2

2 schematic case

realistic shape

V.G., EPJ-ST (2008)

Wavefunction+ Resonance decays

Slide23

mesons

2 for mesons

3 for baryons

quarks

Impact of non zero

v

n

(only even)

baryons

Now we should add also v

3

2

, v

2

*v

3

, … on an e-b-e basis

Kolb-VG, PRC

69, 051901(R) (2004)

This is another source of QNS breaking (may be small)!

Slide24

Very Preliminary on radial flow impactSame approach used for the pTspectra and B/M ratio, but with an anisotropic radial flow in the quark distrib. function

bT(r,f)=

b0(r) +b2(r)*cos(2f)

About20% breaking of QNS, including:- 3D- finite width wave function- anisotropic radial flowfrom coal. only

Slide25

- Only coalescence! No fragmentation contrib.- Radial flow not properly includedV.

Minissale, Master Thesis (UniCT)

One should look also at other vn’s

What predict hydro or EPOS?v3 from jets is about zeroMore sensitive to coal contrib.Large difference B vs M up to7 GeV

Slide26

Summary and Outlook

Coal. prediction from RHIC to LHC are ok!

with no parameters changeNot clear if an(other) approach is able to describe p/

p, K/L, W/f ratio + spectra + vn(pT) pT [2-8 GeV] Breaking of vn QNS scaling expected,

missing a realistic study (3D, finite width

):

- b(

r,f) impact -

vn contamination in ebe

- (fragmentation contribution)

Look at v3 B

vs M at pT≈2-8 GeV

can provide further insight

Slide27

Slide28

Quark Number Scaling?!

0-20%

20-60%

QNS scalingB. Jacak, ERICE2012

Slide29

FMNB(03)

Hwa

-

Yang(06)Work from others…Centrality evolutionf and WExtension to all pTSame approach s GKL in p-space, Unitarity forced (like ALCOR)

but parton distribution function fitted

to pion and protons (5 parameters)

Wang-Song-Shao

,PRC91 (2015) 014909

Slide30

Wave function & v

2

scaling

Dp momentum width of w.f.Baryon-to-Meson breaking of the scaling

Wavefunction+ Resonance decays

Breaking :

increasing with

D

p

decreasing with pT

Slide31

Bulk : Charge Fluctuations

Recombination with all the quark converted into baryon and meson

Correlations c

ikNeglecting: Hadronic diffusion Gluons

Close to the value used in

GKL, PRC68 : N

q

~ 1200

ALCOR, PLB**: N

q

~ 1300

Statistical model

N

had at Tc & from recombination N

quark

C. Nonaka et al., nucl-th/0501028

N

had = 507 (635)

Nquark= 1125 (1377)

( ) nonet mesons +octet & decuplet baryons

STAR, PRC68

(2003) 44905

Slide32

E791



-

beam: - hard cc production;- c recombine with d valence from - -> D- enhancement Braaten, Jia, Mehen: Phys. Rev. Lett. 89, 122002 (2002)

Quark-Antiquark Recombination in the Fragmentation Region

K.P. Das & R.C. Hwa: Phys. Lett. B68, 459 (1977):

Sea quarks Recombination at X

F = 0Rapp and Shuryak, Phys. Rev. D67, 074036 (2003)

Leading Particle Effect

Reservoir of partons modifies hadronization

Similarly for

p

+

/p-, K+/K-

at ISR/Fermilab (late ‘70)

In HIC the resorvoir

is the thermal bulk!



=0 from LO fragmentation

beam

Slide33

R.q.Wang, J.Song and F.L. Shao,Phys.Rev. C91 (2015) 1, 014909Same approach in p-space, but parton distribution function fittedto pion and protons (5 parameters)

Works from others …