Документ взят из кэша поисковой машины. Адрес оригинального документа : http://lav01.sinp.msu.ru/~igor/seminar/CorrFlow_In_AMPT_vlk.pdf Дата изменения: Tue Mar 5 23:37:09 2013 Дата индексирования: Thu Feb 27 21:07:14 2014 Кодировка:

"Higher-order anisotropic flows and dihadron correlations in Pb-Pb in AMPT" Jun Xu and Che Ming Ko Phys.Rev. C84 (2011) 044907, arXiv 1108.0717
.. . , 5 2013


Motivations
1 .
Recently, results from the first Pb-Pb collisions at sNN = 2.76 TeV at the Large Hadron Collider (LHC)have attracted a lot of attentions [15­18].-> ALICE Besides, experimental data on higher-order flows [20] ].-> ALICE and dihadron correlations [21] >CMS have also become available

2.
In more old work [22] ->Xu,Ko studied Pb-Pb collisions atsNN = 2.76 TeV in a multiphase transport (AMPT)model. The AMPT model is a hybrid model with the
initial particle distribution generated by the heavy ion jet interaction generator (HIJING) model [23] through Lund string fragmentation + Zhang's parton cascade (ZPC) model [24] +a spatial coalescence model to hadrons

+the scatterings among them are described by a relativistic transport (ART) model [25].

.

3. Description of High harmonics and Ridge effect in AMPT. 2Part and Flow correlation 4.


Some useful formulae, I


Some useful formulae, II


Some useful formulae, III


Some useful formulae, IV


Results, A. Anisotropic flows, centrality

AMPT 1. || >1 2. || < 0.8 3. AMPT . [22] 40-50%


Results, B. Anisotropic flows, pT
0-5% 30-40%

1. n=2,3,4,5 good for 30-40% 2. Weak dependence on || >1 or >2


B. Dihadron correlations


2D-distributions || vs ||. Dihadron correlations
With final state interactions Without final state interactions

1. Peak at || =0 and Ridge up to || =4 near ||0 2. Ridge disappear if both partonic and hadronic scatterings switch off


1D-distributions. B. Dihadron correlations, ||and pT
Jet region Ridge region

trigg

1. 2- Jet region pTtrigg 2. Ridge region 3. || 2-

«» n (pTtrigg), .. ! n pTtrigg - Jet region


1D-distributions. B. Dihadron correlations, ||
Short- range Long- range Their difference , || Long- range Short- range , Away- side , Near-side pTtrigg

Solid black line - With FSI Near- side Away- side Dashed red line - Without FSI, as in ~pp FSI , jetquenching Away- side FSI.




Lets see these formulae conserning Scalar Production needs additional integration over paT . Lets take (7) and write additional integration



Lets take (7) and write additional integration



a dpT

dN same dd

e



a dpT

dN mix dd

a trig e {1 vn ( pT ) vn ( pT ) cos(n )

a trig a trig FF ( vn ( pT ), vn ( pT )) cos(n ) NF ( , , pT , pT )}



a dpT

dN same dd

e

dN mix dd



e

{1

trig vn ( pT )

[

a a dpT vn ( pT ) cos(n )

]



[

a trig a dpT FF ( vn ( pT ), vn ( pT )) cos(n )

]

[

a trig a dpT NF ( , , pT , pT )

]} }



dN mix dd



e

{1

trig int vn ( pT ) vn cos(n )

trig trig FF int ( vn ( pT )) cos(n ) NF int ( , , pT )

So, you see four terms : 1 + (diffInt)flow + FlowFluct + NonFlow




Some conclusions for : 1. Main difference from Standard 2 particle correlations is the whole interval over pTa instead of (p1,p2) 2. We need consider various regions || <1, 2<|| <4, ... to study Jet- region and Ridge- region 3. We need consider Away- side and Near-side regions ||0 and ||

It may allows us to separate the contributions Flow, Fluctuations and Nonflow by comparison : in pp, pPb, PbPb collisions