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18 Revision 1.1.2.1 2003/04/14 17:33:50 hristov
19 Merging with v3-09-08 (part1)
21 Revision 1.1 2003/03/24 16:49:23 morsch
22 Slow nucleon generator and model.
27 // Experimental data inspired Gray Particle Model for p-Pb collisions
29 // The number of gray nucleons is proportional to the number of collisions.
30 // The number of black nucleons is proportional to the number of collisions
31 // Fluctuations are calculated from a binomial distribution.
34 #include "AliSlowNucleonModelExp.h"
35 #include "AliCollisionGeometry.h"
38 ClassImp(AliSlowNucleonModelExp)
40 AliSlowNucleonModelExp::AliSlowNucleonModelExp()
42 // Default constructor
50 void AliSlowNucleonModelExp::GetNumberOfSlowNucleons(AliCollisionGeometry* geo,
51 Int_t& ngp, Int_t& ngn, Int_t & nbp, Int_t & nbn)
54 // Return the number of black and gray nucleons
56 // Number of collisions
58 Int_t nu = geo->NwN() + geo->NNw();
60 // Mean number of gray nucleons
62 Float_t nGray = fAlphaGray * nu;
63 Float_t nGrayNeutrons = nGray * fN / (fN + fP);
64 Float_t nGrayProtons = nGray - nGrayNeutrons;
66 // Mean number of black nucleons
67 Float_t nBlack = fAlphaBlack * nu;
68 Float_t nBlackNeutrons = nBlack * fN / (fN + fP);
69 Float_t nBlackProtons = nBlack - nBlackNeutrons;
71 // Actual number (including fluctuations) from binomial distribution
76 ngn = gRandom->Binomial((Int_t) fN, p);
80 ngp = gRandom->Binomial((Int_t) fP, p);
83 p = nBlackNeutrons/fN;
84 nbn = gRandom->Binomial((Int_t) fN, p);
88 nbp = gRandom->Binomial((Int_t) fP, p);
92 void AliSlowNucleonModelExp::SetParameters(Float_t alpha1, Float_t alpha2)
94 // Set the model parameters