Äîêóìåíò âçÿò èç êýøà ïîèñêîâîé ìàøèíû. Àäðåñ îðèãèíàëüíîãî äîêóìåíòà : http://qfthep.sinp.msu.ru/talks2013/Geometric_properties_and_charged_particles_Seryakov.pdf Äàòà èçìåíåíèÿ: Fri Jun 28 15:26:49 2013 Äàòà èíäåêñèðîâàíèÿ: Thu Feb 27 20:34:06 2014 Êîäèðîâêà:

Geometric properties and charged particles yields behind Glauber model in high energy pA and AA collisions
T.Drozhzhova, G.Feofilov, V.Kovalenko, A.Seryakov Saint-Petersburg State University (Lab. of Ultra-High Energy Physics)

Saint-Petersburg June 28, 2013
The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Terminology

· Nucleon-participants ( ) ­ nucleons collided at least once · Nucleon-spectators ( = 2 - =216 - ) ­ nucleons which didn't interact · Number of nucleon-nucleon collisions ( ) · Multiplicity of charged particles ( )
2


Charged-particle pseudorapidity density at midrapidity normalized to Npart

most central AA collisions pp collisions

AA collisions are not simple a superposition of nucleon collisions!

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Standard Glauber model (SGM)
· · · · -collision ­ sequence of nucleon-nucleon collisions. Nuclear density ­ distribution of the Woods-Saxon. Trajectories of nucleons are linear from experiments =const = 0
0 A

1 1 + -

= 0.545

= 1.07

1

3



- nucleon density in the center of nucleus - radius of the nucleus - atomic number -diffusivity

· Energy loss in nucleon collisions due to particle production are not considered
The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Standard Glauber model (SGM)
· · · · -collision ­ sequence of nucleon-nucleon collisions. Nuclear density ­ distribution of the Woods-Saxon. Trajectories of nucleons are linear from experiments =const = 0
0 A

1 1 + -

= 0.545

= 1.07

1

3



- nucleon density in the center of nucleus - radius of the nucleus - atomic number -diffusivity

Number of nucleon-participants (Npart) and nucleon-nucleon collisions (Ncoll)
· Energy loss in nucleon collisions due to particle production are not considered
The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Standard Glauber model (SGM)

. Ivanov: Long-range correlations and collectivity in pp and collisions, SPSU 2010, 42

G. Antchev et al. (OTEM Collaboration) First measurement of the total proton-proton cross-section at the LHC energy of = 7 TeV, EPL, 96 (2011) 21002

Calculated for each nucleon-nucleon collision



=





The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Standard Glauber model (SGM)

. Ivanov: Long-range correlations and collectivity in pp and collisions, SPSU 2010, 42

G. Antchev et al. (OTEM Collaboration) First measurement of the total proton-proton cross-section at the LHC energy of = 7 TeV, EPL, 96 (2011) 21002

Calculated for each nucleon-nucleon collision



=





The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Models with energy-momentum conservation

· Modified Glauber model · Non-Glauber MC model (V. Kovalenko) · HIJING

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Models with energy-momentum conservation

· Modified Glauber model · Non-Glauber MC model (V. Kovalenko) · HIJING

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Modified Glauber model (MGM)
· Each nucleon in collisions loses in the inelastic collision the fixed portion (1-k) of momentum in the center of mass system[1]:

p = kp
· This loss of momentum goes to the production of charged and neutral particles
· One can define parameter k by fitting the available experimental data on charged-particle multiplicity yields in AA collisions · New: Nucleon core · New: Secondary collisions ­ collisions between nucleons of one nucleus

[1]. G.Feofilov, A.Ivanov, Number of nucleon-nucleon collisions vs energy in modified Glauber calculations // Journal of Physics G CS, 5, (2005) 230-237

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Total multiplicity of charged particles for the most central AA collisions

our estimates from [2]


=






=
=1







[1] B. Back et al. (PHOBOS Collaboration) Comparison of the Total Charged-Particle Multiplicity in High-Energy Heavy Ion Collisions with e+e- and pp/p(anti)p Data // arXiv:nucl-ex/0301017v1 28 Jan 2003 [2] ALICE experimental pseudo-rapidity distribution 2011 APW Guilbaud Maxime & Hans Dalsgaard 16.04.2012 [3] K. Aamodt et al. (ALICE Collaboration) Centrality dependence of the pseudorapidity density distribution for charged particles in Pb-Pb collisions at SNN = 2.76 TeV, arXiv:1304.0347 [nucl-ex], 2013

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


AA - scaling

2,76 TeV
[2] [1]

200 GeV
[3]

19,6 GeV

[1]B. Back et al. (PHOBOS Collaboration) Comparison of the Total Charged-Particle Multiplicity in High-Energy Heavy Ion Collisions with e+e- and pp/p(anti)p Data// arXiv:nucl-ex/0301017v1 28 Jan 2003 [2]ALICE experimental pseudo-rapidity distribution 2011 APW Guilbaud Maxime & Hans Dalsgaard 16.04.2012 [3]K. Aamodt et al. (ALICE Collaboration) Centrality dependence of the pseudorapidity density distribution for charged particles in Pb-Pb collisions at SNN = 2.76 TeV, arXiv:1304.0347 [nucl-ex], 2013

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Models with energy-momentum conservation

· Modified Glauber model · Non-Glauber MC model (V. Kovalenko) see report at the present workshop · HIJING

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Non-Glauber MC model

· Partonic picture of nucleons interaction. · Every parton can interact with other one only once (contrary to Glauber supposition of constant nucleon cross section) · Nucleon is participating in the collision if at least one of it's partons collides with parton from another nucleus. · Parameters of the model are constrained from the p-p data on total inelastic cross section and multiplicity · Additional requirement is consistent description of the multiplicity in min. bias p-Pb collisions
V. Kovalenko, Phys. Atom Nucl 76 (accepted), arXiv:1211.6209 [ hep-ph]; V. Kovalenko, V. Vechernin. PoS (Baldin ISHEPP XXI) 077, 2012, arXiv:1212.2590 [ nucl-th]

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Systematic uncertainties of the model

No fusion

with fusion rstr=0.2-0.3fm

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Charged multiplicity over Npart

Pb-Pb multiplicity is reproduced well in the model

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Models with energy-momentum conservation

· Modified Glauber model · Non-Glauber MC model · HIJING

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


HIJING
· HIJING is the MC event generator for hadron production in high energy pp, pA, AA collisions. · Gives reasonable description of multiplicity yields.

HIJING, R. Xu, W.-T. Deng, and X.-N. Wang, arXiv:1204.1998 Wei-tian Deng, Xin-Nian Wang, Rong Xu Phys.Lett.B701:133-136,2011 B. Abelev et al. (ALICE Collaboration) Phys. Rev. Lett. 110, 032301 (2013)

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


pA collisions

· · · ·

Glauber model Modified Glauber model Non-Glauber MC model HIJING

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


pPb collisions 5.02 TeV

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


pA collisions

at 5.02 TeV ALICE p-Pb MinBias 7.87 (A.Ser) 7.9±0.6 (ALICE[1]) 4.3±0.3 6.2±0.6 6.5

at 200GeV at 2.76 TeV ALICE Pb-Pb PHOBOS d-Au MinBias 0-5% centrality 8.4 (A.Ser) 5.0±0.3 408 (A.Ser) 397

Glauber MGM Non-Glauber HIJING

8.1±0.7 [2]

[1] B. Abelev et al. (ALICE Collaboration) Phys. Rev. Lett. 110, 032301 (2013) [2] B. Back et al. (PHOBOS Collaboration), Phys. Rev. Lett.93, 082301 (2004 ) [3] AMPTJ . Albaete, N. Armesto, R. Baier, et al., Int. J. Mod. Phys. E 22, 1330007 (2013), arXiv:1301.3395

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Corrections
Charged-particle pseudorapidity density at midrapidity normalized to Npart at 5.02 TeV ALICE p-Pb

MinBias

Glauber

7.87 (A.Ser) 7.9±0.6 (ALICE) 4.3±0.3
6.2±0.6 6.5

MGM
NonGlauber HIJING

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Conclusions
· MGM, non-Glauber, HIJING and AMPT ­ all these models gives smaller values of compared to Glauber · This indicates considerable stopping of nucleons in AA and pA interactions at the LHC energies.

MinBias

at 5.02 TeV ALICE p-Pb 7.87 (A.Ser) 7.9±0.6 (ALICE) 4.3±0.3 6.2±0.6 6.5

Glauber MGM Non-Glauber HIJING

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Backup

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Backup
pPb 5.02 TeV

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Backup



1 2 = < > 2

The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia


Backup
PbPb 2.76 TeV

For the most central collisions:










= 0.35





The XXI International Workshop High Energy Physics and Quantum Field Theory June 23 ­ June 30, 2013 Saint Petersburg Area, Russia