a.litvinenko vblhep jinr Определение центральности столкновения...
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A.Litvinenko VBLHEP JINR
Определение центральности столкновения ядер с использованием калориметра cпектаторов
в эксперименте MPD@NICA
A.Litvinenko, litvin@moonhe.jinr.ru
M.Golubeva, F.Guber, A.Ivashkin, A.Kurepin,INR, Moscow
A.Litvinenko, E.Litvinenko, A.Isupov, I.Migulina, V.Peresedov, JINR, Dubna
A.Litvinenko VBLHEP JINR
IntroductionSome definitionsSpectators
UrQMD generatorUrQMD generator LAQGSM generatorLAQGSM generator UrQMD - SHIELD - LAQGSMUrQMD - SHIELD - LAQGSM ConclusionsConclusions
OutlineOutline
A.Litvinenko VBLHEP JINR
NICA
A.Litvinenko VBLHEP JINR
MPD
A.Litvinenko VBLHEP JINR
Quasi-Classical pictureb – not observable observables b
Nuclear-Nuclear collisions
6
R
geo Rbdb2
0
2)2(2
Centrality classification
Value of impact parameter
Geometrical cross section
8%)(2 fm 42 b
In percent from the geometrical cross section
% 50 40Centrality
Corresponds to the region impact parameter
fm 9.5 (15)fm 0.63 )2( 4.0min Rb
fm 10.6 (15)fm 0.71 )2( 5.0max Rb
%) ( 2R
b
2R
b
(b
(b2
A
max
2
A
min
geo
max
geo
min
σσ
σσ ))
;)b(bdb)b(b
0
22 ππσ
Centrality classification
1. (fm) b bb maxmin
2. Fraction from total cross-section
%) ( 2Rb
2Rb
2
A
max
2
A
min
3. Number of participant
…. ?
.partN
Impact parameter
%) ( 2Rb
2Rb
2
A
max
2
A
min
8
Centrality classification
A.Litvinenko VBLHEP JINR
The importance of the centrality classification
elliptic flow scaling with space eccentricity short equlibration time
Space eccentricityElliptic flow
...)2cosv2cosv21(2
121
ddN
ε=A 2
2
v
Nuclear Physics A V757, No. 1-2 , p.184,2005
A.Litvinenko VBLHEP JINR
The importance of the centrality study
Jet Quenching – nuclear modification factor vs centrality
Nuclear Physics A V757, No. 1-2 , p.184,2005
Nuclear modification factor
A.Litvinenko VBLHEP JINR
The importance of the centrality study
A.Litvinenko VBLHEP JINR
A.Litvinenko VBLHEP JINR
Nucleon spectators (spectrum)
Yu.Bayukov et al ., YaF V.35, No. 4, p.960, (1982)
R.Ammarи et al., Pisma v JETF, V.94, No. 4, p.189, (1989)
nXPb
pXEm ~
nXC
X )p(backward Em
A.Litvinenko VBLHEP JINR
Spectator spectrum
)exp(-T/TC pd
dE 03
МэВ 10 - 5 T0
)Tmm-PP
exp(-C pd
dE
0N
2NFS
3
)σ
Θ•)
σ
)pp(•=
pd
σdE
Θp2
2
2
2b
3 2exp(-
2
-exp(-C
0.022 - 0.016 p
Tm GeV/c; 0.22 - 0.15
mTE
2b
0N
N
0bp
A.Litvinenko VBLHEP JINR
A.Litvinenko VBLHEP JINR
Front view of ZDC. The squares size is 5 x 5 cm x cm
A.Litvinenko VBLHEP JINR
ZDC@MPD geometrical efficiency
.)tot(N/)ZDC(N )ZDC( SS
central hole
out of ZDC
0.99 >)ZDC(ε
% 70 50 )d)
2exp(-
)d)2
exp(-
)ZDC(
0 2
2
r 2
2
ZDCint/L
A.Litvinenko VBLHEP JINR
Simulation Transport – Geant3 and Geant4, generates UrQMD and LAQGSM
framework MpdRoot
A.Litvinenko VBLHEP JINR
URQMD generator, Sqrt(S)=5 GeV
Total kinetic energy of all nucleonsdirected to ZDC
Optimistic results with UrQMD
A.Litvinenko VBLHEP JINR
UrQMD generator, Sqrt(S)=9 GeV
Total kinetic energy of all nucleonsdirected to ZDC
Optimistic results with UrQMD
0.782m- N
=A)S(
EΔ=ε
NN
ZDC
A.Litvinenko VBLHEP JINR
The accuracy of impact parameterdetermination for MC with UrQMD
% 18 E GeV 20 E GeV 114 E(b)
b fm 0.35 b ; fm 0
=δ;=Δ;=
=δ;=Δ=b
% 10 E GeV 38 E GeV 392 E(b)
% 13 b fm 0.67 b ; fm 5
=δ;=Δ;=
=δ;=Δ=b
C - N(b)
N(b) b
A
1 b ;
A
C-
N(b)1/ E NT E T E(b)
N(b)1/ N N N C;
bb
=δ;)b(N=Δ)b(N
=b
=δ;•=Δ);b(N•=
=δ;=Δ+b•A=)b(N
% 7 E GeV 49 E GeV 673 E(b)
% 9 b fm 0.87 b ; fm 10
=δ;=Δ;=
=δ;=Δ=b
% 150 <<β;E
β=
E
EΔ
22
The centrality resolution evaluations √S=9 AGeVThe centrality resolution evaluations √S=9 AGeV
A.Litvinenko VBLHEP JINR
But
The NA49 collaboration. Eur. Phys. J., A2, 383, (1998)
A.Litvinenko VBLHEP JINR
LAQGSM high-energy event generatorLAQGSM high-energy event generator
But
A.Litvinenko VBLHEP JINR
LAQGSM generator, Sqrt(S)=5 GeV
Total kinetic energy of all nucleonsand fragments directed to ZDC
Taking into account spectator fragments
A.Litvinenko VBLHEP JINR
LAQGSM generator, Sqrt(S)=9 GeV
Total kinetic energy of all nucleonsand fragments directed to ZDC
Taking into account spectator fragments
A.Litvinenko VBLHEP JINR
SHIELD event generator
A.Litvinenko VBLHEP JINR
LAQGSM, Sqrt(S)=5 GeV
Total kinetic energy of all nucleonsand fragments directed to ZDC
URQMD, Sqrt(S)=5 GeV
A.Litvinenko VBLHEP JINR
A.Litvinenko VBLHEP JINR
At large impact parameters the most of spectator nucleons are bound in fragments.
The NA49 collaboration. Eur. Phys. J., A2, 383, (1998)
Experimental data : the deposited energy for different types of spectators in dependence of
the centrality
A.Litvinenko VBLHEP JINR
All nucleons directed to the hole of ZDC (rectangle 10x10cm2)
0 % - 60 % 60 % - 80 % 80 % - 100 %
mrad 100.3 -3 30.=rad•~θ
A.Litvinenko VBLHEP JINR
At large impact parameters the most of spectator nucleons are bound in fragments.
The NA49 collaboration. Eur. Phys. J., A2, 383, (1998)
Experimental data : the deposited energy for different types of spectators in dependence of
the centrality
33
The centrality resolution evaluations The centrality resolution evaluations √S=9 AGeV√S=9 AGeV
Kinetic energy of all spectators directed to solid angle 5º
The centrality resolution evaluations √S=9 AGeVThe centrality resolution evaluations √S=9 AGeV
The centrality resolution evaluations √S=9 AGeVThe centrality resolution evaluations √S=9 AGeV
The centrality resolution evaluations √S=9 AGeVThe centrality resolution evaluations √S=9 AGeV
A.Litvinenko VBLHEP JINR
The centrality determination: ZDC (energy) + number of charged barrel
tracks
A.Litvinenko VBLHEP JINR
UrQMD - SHIELD - LAQGSM
b < 3 фм (0 – 4 %)
A.Litvinenko VBLHEP JINR
UrQMD - SHIELD - LAQGSM
3 фм < b < 9.5 фм (4 – 40 %)
A.Litvinenko VBLHEP JINR
UrQMD - SHIELD - LAQGSM
9.5 фм < b (40 – 100 %)
A.Litvinenko VBLHEP JINR
Centrality determination in some experiment
y=0 y=3y>6
STARPHENIXNA49
NA49 ZDC Only
STAR TPC only
PHENIX BBC & ZDC
A.Litvinenko VBLHEP JINR
Conclusions
• The SHIELD and LAQGSM could be used for NICA/MPD simulations under mpdroot.
• The SHIELD and LAQGSM angular distributions of the spectators differ from URQMD picture.
• The experimental study of the spectator distributions and calorimeter resolution have to be performed on the extracted beam of NUCLOTRON-M at the fixed target.
A.Litvinenko VBLHEP JINR
Conclusions
•Работа выполнена при поддержке грантов РФФИ
10-02-01036-а
11-02-01026-а
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Backup slidesBackup slides
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A.Litvinenko VBLHEP JINR
Fast evaluations: the movement of spectators at NICA/MPD
bpXY
Z
T 1 B
QB0.3Ap
- Ap
zQB0.3cos
QB0.3Ap
)z(y
ApzQB0.3
sinQB0.3Ap
)z(x
T
z
T
z
T
ApzQB0.3
cos12QB0.3Ap
yx )z,B(z
T22
Ap
zQBz
p
pzB
Ap
zQB
zz
T
z
0.3
2
1 ; ),( 0.2
0.3
The conclusion:Magnetic field of MPD will not change the polar angles for spectators at ZDC position it will only slightly changes the azimutal angles
06 zT p/p
A.Litvinenko VBLHEP JINR
A.Litvinenko VBLHEP JINR
A.Litvinenko VBLHEP JINR
A.Litvinenko VBLHEP JINR
Centrality classification
C.E.Aguilar et al., Brazilian Journal of Physics, V.34,No.1,p.319,(2004)
A.Litvinenko VBLHEP JINR
Calorimeter No.1
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Calorimeter No.1
A.Litvinenko VBLHEP JINR
Calorimeter No.1
A.Litvinenko VBLHEP JINR
Calorimeter No.1
A.Litvinenko VBLHEP JINR
Linearity
Resolution
Longitudinal distribution
A.Litvinenko VBLHEP JINR
Calorimeter No.1
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CONCLUSION
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Пространственное разрешение
A.Litvinenko VBLHEP JINR
)c/GeV(Pz )c/GeV(Pz
)c/GeV(Pz)c/GeV(Pz
partN
)c/GeV(Px
)GeV(EZDC
partN
partN
ZDC
A.Litvinenko VBLHEP JINR
ZDC + Multiplicity
1000 Min Bias
chN
A.Litvinenko VBLHEP JINR
ZDC + Multiplicity
1000 Min Bias
chN
chN chN
chN
A.Litvinenko VBLHEP JINR
A.Litvinenko VBLHEP JINR
PHENIX
ZDC + BBC
A.Litvinenko VBLHEP JINR
NA49
VCAL (ZDC)
65
TIME = 0 fm/c, 0.7
66
TIME = 1 fm/c, 0.6
67
TIME = 2 fm/c, 0.5
68
TIME = 3 fm/c, 0.3
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