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Дата изменения: Wed Sep 16 16:32:47 2009
Дата индексирования: Tue Oct 2 00:45:58 2012
Кодировка:

(for CMS Collaboration)

Sergey Petrushanko

Elliptic flow studies in heavy-ion collisions using the CMS detector
14th Lomonosov Conference on Elementary Particle Physics 19-25 A ug us t 200 9
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Elliptic flow in non-central heavy-ion events

transverse plane

py

)

px

Kolb P.F., Heinz U., nucl-th/0305084

Initial spatial anisotropy results in elliptic flow of finite particles. Azimuthal anisotropy of particles is a signature of termalizasion.
Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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Azimuthal distribution on RHIC

R azimuthal angle of the reaction plane

STAR Collaboration, Phys.Rev.Lett.90:032301,2003.

dN ( p ) = N 0 (1 + 2v1 cos( p - R ) + 2v 2 cos 2( p - R ) + ...) d Ellip v2 = < 2 tic flow cos (-R) >
= t an
-1

(py/px)

p

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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v2 current data and prediction for LHC

Simple extrapolation for LHC: v2 = 0.07

Alessandro B et al., 2006 J. Phys. G: Nucl. Part. Phys. 32 1295

Simple extrapolation gives slight increasing of v2 for LHC energy (but a number of models predicts slight decreasing of v2)
Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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v2 vs. pT RHIC and LHC

N. Armesto et al., J. Phys. G 35 (2008) 054001.

A. K. Chaudhuri, Phys. Lett. B 672 (2009) 126

M PC par ton cascade of M ol nar f or RH I C and L H C, b = 8 f m.

V i scous hy dr ody nami cal cal cul ati ons f or RH I C and L H C, mi ni mum bi as col l i si ons.

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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Elliptic flow on LHC: experiments

ALICE

ATLAS

CMS

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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CMS experiment on the LHC
Silicon Tracker || < 2.4 Electromagnetic Calorimeter || < 3.0 Hadron Calorimeter
barrel and endcap with HF-calorimeter up to

|| < 3.0

|| < 5.2 Muon Chambers || < 2.4 + CASTOR detector 5.3 < || < 6.4 + Zero-degree calorimeter + TOTEM

Magnetic field: 3.8 Tesla

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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CMS experiment on the LHC
Tracker system: Silicon pixel layers ( 3 in barrel || < 1.5, 2 in endcap 1.5 < || < 2.4) Silicon strips layers (10 in barrel || < 1.5, 12 in endcap 1.5 < || < 2.4) Calorimeter system: ECAL electromagnetic (crystals of lead tungstate PbWO4) || < 3.0 HCAL hadron (active plastic scintillator tiles interspersed between stainless steel and brass absorber plates) || < 3.0 HF hadron forward (steel absorbers and embedded radiation hard quartz fibers) 3.0< || < 5.2

Muon Coil HCAL ECAL Tracker

Excellent coverage: Tracker ~ 5 units of rapidity and 2 Calorimeter > 10 units of rapidity and 2 Momentum resolution: ~ 2% of momentum resolution for tracks w ith pT < 100 GeV/c

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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From RHIC to LHC: time and statistics for first heavy-ion run
Physics proton-proton run on LHC w ill start in mid-November 2009 Two w eeks heavy-ion run w ill be expected in the end of 2010 Expected LHC one week of 1-st year run for PbPb collisions at ~ 4 TeV L=10 b -1 ~ 70M events STAR (similar acceptance as CMS) 2000 year, first publications on Elliptic flow on RHIC: ~ 25M events
Statistical reach at CMS will be better or comparable with the RHIC results

Elliptic flow one of the priorities of the CMS heavy-ion group for the first heavy-ion run on the LHC
Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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Reconstruction of the reaction plane in CMS
CMS Tracker Reconstructed Tracks
The reaction plane at the CMS can be determined independently by different detector subsystems and in different pseudorapidity windows.

CMS Calorimeters
ECAL and HCAL

HYDJET generator was used to simulate PbPb events at the LHC.
I.P. Lokhtin and A.M. Snigirev, Eur. Phys. J. C 46 (2006) 211, http://lokhtin.web.cern.ch/lokhtin/hydro/hydjet.html

GEANT-based software was used to simulate CMS responses.
Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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Reaction plane in CMS with calorimeter
PbPb, b=9 fm

reco R

gen R

Azimuthal distribution of the reconstructed energy

Event plane resolution w ith ECAL: 0.37 radian

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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v2 vs. pT CMS tracker, PbPb b=9 fm
Tracks with pT >0.9 GeV/c
- generated - reconstructed

(by Event Plane method) The uncertainties of the CMS Tracker detector is not higher than 3% Methods of v2 extraction
- v {EP} in generated events
2

- original events - Lee-Yang zeros method

Non-flow corrections
Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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v2 vs. CMS tracker
PbPb, b=9 fm

Tracks with pT >0.9 GeV/c
- generated - reconstructed

(by Event Plane method)
Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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Summary

v2 study at LHC energy can give important information about quark matter.

Heavy-ion collisions are expected at the LHC in the end of 2010.

CMS detector at the LHC is ready to study elliptic flow by different detector subsystems, in different pseudorapidity windows and by different methods.

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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BACK UP

Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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Materials about elliptic flow at the CMS
G.Kh.Eyyubova, V.L. Korotkikh, I.P. Lokhtin, S.V. Petrushanko, L.I. Sarycheva, A.M. Snigirev (SINP MSU, Russia) & David Krofcheck (Auckland, NZ)

CMS NOTE-2003/019, "Azimuthal Anisotropy and Jet Quenching in Heavy Ion Collisions with CMS Calorimetry"
http://cms-secr.web.cern.ch/cms-secr/documents/03/note03_019.pdf

Chapter 4 "Elliptic Flow" in PTDR Addendum "High Density QCD with Heavy Ions"
http://cdsweb.cern.ch/record/1019832/files/lhcc-2007-009.pdf

CMS AN-2007/004 "Azimuthal Anisotropy in Heavy Ions Collisions with CMS Tracker"
http://cms.cern.ch/iCMS/jsp/openfile.jsp?tp=draft&files=AN2007_004_v4.pdf

Quark Matter 2008 Proceeding
http://cms.cern.ch/iCMS/jsp/openfile.jsp?type=CR&year=2008&files=CR2008_022.pdf Sergey Petrushanko (CMS Collaboration), Elliptic Flow, Lomonosov 2009

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