July 2007Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France...
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Transcript of July 2007Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France...
![Page 1: July 2007Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev 1 Direct photons for FASTMC Sergey Kiselev,](https://reader035.fdocuments.net/reader035/viewer/2022081603/5697c02a1a28abf838cd7fb5/html5/thumbnails/1.jpg)
July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Direct photons for FASTMC
Sergey Kiselev, ITEP, Moscow Introduction Prompt photons for FASTMC Thermal photons from hot hadron gas for
FASTMC Conclusions and next steps
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Introduction - UHKM package Universal Hydro Kinetic Model (UHKM) (
http://uhkm.jinr.ru). Now includes: FASTMC – FAST Monte-Carlo hadron freeze-out generator. Particles are generated on the chemical or thermal freeze-out hyper-surface represented by a parameterization or a numerical solution of relativistic hydrodynamics. UKM – Universal Kinetic Model. Treats further evolution (scattering and decays) solving relativistic Boltzmann equations numerically.SPHES – Smoothed Particle Hydrodynamics Equations Solver. Solves (1+3D) – relativistic perfect hydrodynamics equations at given initial condition and equation of state and provides hadron freeze-out hyper-surface.
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Introduction - photons for UHKM decay photons: trivial (π0, , … decays) prompt photons (high pT):
p+p – data fit & A+B – binary scaling thermal photons (low pT):
thermal rates from QGP/Hot HadronGas (HHG) have to be convoluted over the space-time history of the A+B reaction given by hydrodynamics
hard-thermal photons (intermediate pT): ??? Should think how jet-γ conversion, jet-bremsstrahlung could be implemented in UHKM.
ITEP group has prepared for FASTMC: prompt photons thermal photons from HHG in Bjorken -(1+1)-hydrodynamics Have been implemented into FASTMC by Ludmila Malinina
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Prompt photons: RHIC and D0 pp data
Srivastava’s fit does not describe D0 data at xT>0.1
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Prompt photons: pp data fit + binary scaling
PHENIX hep-ph/0609037
(√s)5 Ed3σ/d3p = F(xT,y) One can use a data tabulation of
the F(xT,y) to generate prompt photons.
A+B:
Ed3N/d3p(b)=
Ed3σpp/d3p AB TAB(b)=
Ed3σpp/d3p Ncoll(b)/σppin
Nuclear effects (Cronin, quenching, …) are not taken into account.
Realization: GePP.C macros for ROOT
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Generator of Prompt Photons (GePP): results
Comparison with RHIC data Prediction for LHC
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Thermal photons Thermal rates from QGP:
Perturbative QCD, the lowest order in s
qq gγ, qg qγ
dN/d4xd3p s ln(0.23E/sT) exp(-E/T) T2/E, ZP C53, 433bremsstrahlung
dN/d4xd3p s exp(-E/T) T2/E, PL B510, 98 Thermal rates from hot hadron gas:
effective theory for hadron interactionsπρ πγ, ππ ργ, ρ ππγ, ω πγdN/d4xd3p ~ T2.15 exp(-E/T) / exp((1.35 ET)0.77), PL B510, 98
The thermal rates can be convoluted over the space-time history of the A+B reaction given by SPHES
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Thermal production rates from HHG
C.Song and G.Fai, Phys.Rev., C58 (1998) 1689.
parameterizations for the processes ππ →ργ , πρ → πγ, and ρ →ππγ , in which the a1 meson is taken into account properly
F.D.Steffen and M.H.Thoma, Phys.Lett., B510 (2001) 98.For hard photons, E >1 GeV, a rough estimate of this sum plus ω πγ by the parameterization
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Bjorken -(1+1)-hydrodynamics
Proper time and rapidity y Phys.Rev., D27 (1983) 140
There is no dependence onLorenz boost variable y:
Landau hydrodynamical model, viscosity and conductivity are neglected
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Photon spectrumPhoton spectra follow from convoluting the photon production rates with the space–time evolution of the collision
For a longitudinally expanding cylinder
For proper time and rapidity y`
For an ideal hadron gas
Main parameters: initial 0 , T0 and Tf (at freeze-out)
Connection with the local rest frame
Realization: GeTP.C macros for ROOT
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Generator of Thermal Photons (GeTP): results
Choosing T0 and 0 one can fit data in the hadron scenario
comparison with data, Tf = 100 MeV
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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GeTP: prediction for LHC
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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GeTP: sensitivity to the parameters
sensitivity to T0 sensitivity to Tf
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Conclusions and next steps
In FASTMC one can generate:
prompt photons
thermal photons from HHG in Bjorken -(1+1)- hydrodynamics
Direct photon data at SPS and RHIC can be reproduced by choosing the T0 and 0 parameters in the hadron scenario
The thermal photons rates can be easy implemented into more realistic hydrodynamics (SPHES, …)
Next step: thermal photons from HHG in (2+1) – hydrodynamics of FASTMC.
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Back up
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July 2007 Workshop of European Research Group on Ultra-Relativistic Heavy Ion Physics, Nantes, France S.Kiselev
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Compton Annihilation
In p+p Hard photons:direct component
q + g + q q + q + g
Photons in A+A
Direct Photons Decay Photons
hard thermal hard+thermal
QGP Hadron gasdirect fragmentation
Preequilibriumphotons
jet--conv.
Medium induced bremsstr.
In A+A picture is much more complicated:
V2=0V2<0V2<0
V2>0V2>0V2>0