1 #ifndef ALIGENTHERMALPHOTONS_H
2 #define ALIGENTHERMALPHOTONS_H
3 /* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * See cxx source for full Copyright notice */
6 //-------------------------------------------------------------------------
7 // author: Sergey Kiselev, ITEP, Moscow
8 // e-mail: Sergey.Kiselev@cern.ch
9 // tel.: 007 495 129 95 45
10 //-------------------------------------------------------------------------
11 // Generator of direct thermal photons for the reaction A+B, sqrt(S)
13 // 1+1 Bjorken scaling hydrodinamics.
14 // 1st order phase transition
15 // QGP + Mixed (QGP+HHG) + HHG (Hot Hadron Gas) phases,
16 // an ideal massless parton gas and ideal massless HHG
18 // F.D.Steffen, nucl-th/9909035
19 // F.D.Steffen and M.H.Thoma, Phys.Lett. B510, 98 (2001)
20 // T.Peitzmann and M.H.Thoma, Phys.Rep., 364, 175 (2002)
22 // photon rates for QGP: Phys.Rep., 364, 175 (2002), section 2.1.1
24 // photon rates for HHG
25 // prates for i rho --> pi gamma, pi pi --> rho gamma and rho --> pi pi gamma:
26 // Song and Fai, Phys.Rev. C58, 1689 (1998)
27 // rates for omega --> pi gamma: Phys.Rev. D44, 2774 (1991)
30 // fAProjectile, fATarget - number of nucleons in a nucleus A and B
31 // fMinImpactParam - minimal impct parameter, fm
32 // fMaxImpactParam - maximal impct parameter, fm
33 // fEnergyCMS - sqrt(S) per nucleon pair, AGeV
34 // fTau0 - initial proper time, fm/c
35 // fT0 - initial temperature, GeV
36 // fTc - critical temperature, GeV
37 // fTf - freeze-out temperature, GeV
38 // fGhhg - effective number of degrees of freedom in HHG
40 // fYMin - minimal rapidity of photons
41 // fYMax - maximal rapidity of photons
42 // in [fYMin,fYMax] uniform distribution of gamma is assumed
43 // fPtMin - minimal p_t value of gamma, GeV/c
44 // fPtMax - maximal p_t value of gamma, GeV/c
45 //-------------------------------------------------------------------------
46 // comparison with SPS and RHIC data, prediction for LHC can be found in
47 // arXiv:0811.2634 [nucl-th]
48 //-------------------------------------------------------------------------
52 #include "AliGenerator.h"
54 class AliGenThermalPhotons : public AliGenerator
58 AliGenThermalPhotons();
59 AliGenThermalPhotons(Int_t npart);
60 virtual ~AliGenThermalPhotons();
61 virtual void Generate();
63 virtual void SetPtRange(Float_t ptmin = 0.1, Float_t ptmax=10.);
64 virtual void SetYRange(Float_t ymin = -1., Float_t ymax=1.);
67 virtual void SetAProjectile(Int_t a = 208.) {fAProjectile = a;}
68 virtual void SetATarget(Int_t a = 208.) {fATarget = a;}
69 virtual void SetEnergyCMS(Float_t energy = 5500.) {fEnergyCMS = energy;}
70 virtual void SetImpactParameterRange(Float_t bmin = 0., Float_t bmax = 0.)
71 {fMinImpactParam=bmin; fMaxImpactParam=bmax;}
72 virtual void SetTau0(Float_t tau0 = 0.1) {fTau0 = tau0;}
73 virtual void SetT0(Float_t T0 = 0.650) {fT0 = T0;}
74 virtual void SetTc(Float_t Tc = 0.170) {fTc = Tc;}
75 virtual void SetTf(Float_t Tf = 0.100) {fTf = Tf;}
76 virtual void SetGhhg(Int_t Ghhg = 8) {fGhhg = Ghhg;}
79 Float_t fMinImpactParam; // minimum impact parameter
80 Float_t fMaxImpactParam; // maximum impact parameter
81 Float_t fTau0; // initial proper time, fm
82 Float_t fT0; // initial temperature, GeV
83 Float_t fTc; // critical temperature, GeV
84 Float_t fTf; // freeze-out temperature, GeV
85 Int_t fGhhg; // number of degrees of freedom in HHG
87 TH1F *fSumPt; // histo with pt from all origins
91 AliGenThermalPhotons(const AliGenThermalPhotons & ThermalPhotons);
92 AliGenThermalPhotons& operator = (const AliGenThermalPhotons & ThermalPhotons) ;
95 ClassDef(AliGenThermalPhotons, 1) // Direct thermal photon generator