Fix bug in building local list of valid files.
[u/mrichter/AliRoot.git] / TEvtGen / EvtGenModels / EvtBtoXsgammaAliGreub.cpp
CommitLineData
da0e9ce3 1//--------------------------------------------------------------------------
2//
3//
4// Copyright Information: See EvtGen/COPYRIGHT
5//
6// Environment:
7// This software is part of the EvtGen package developed jointly
8// for the BaBar and CLEO collaborations. If you use all or part
9// of it, please give an appropriate acknowledgement.
10//
11// Module: EvtBtoXsgammaAliGreub.cc
12//
13// Description: Routine to perform two-body non-resonant B->Xs,gamma decays.
14// It generates an X_s mass spectrum based on a parameterisation of the
15// b->s,gamma photon spectrum of Ali-Greub. The resultant X_s particles may
16// be decayed by JETSET.
17//
18// Modification history:
19//
20// Mark Ian Williams July 20, 2000 Module created
21// Mark Ian Williams July 21, 2000 Module works
22// Mark Ian Williams July 25, 2000 Works for all Xs modes
23// Mark Ian Williams Aug 09, 2000 New values for mass minima
24// Mark Ian Williams Sept 06, 2000 14 parameter M_Xs function
25// Mark Ian Williams Sept 07, 2000 18 parameter M_Xs function
26// Mark Ian Williams Sept 07, 2000 Tidied up the code
27// Mark Ian Williams Sept 10, 2000 Updated parameters
28// Mark Ian Williams Sept 11, 2000 Finalised code
29// Jane Tinslay March 21, 2000 Separated from EvtBtoXsgamma
30// class to allow choice of input models.
31//------------------------------------------------------------------------
32//
33#include "EvtGenBase/EvtPatches.hh"
34
35#include <stdlib.h>
36#include "EvtGenBase/EvtRandom.hh"
37#include "EvtGenModels/EvtBtoXsgammaAliGreub.hh"
38#include <string>
39#include "EvtGenBase/EvtConst.hh"
40#include "EvtGenBase/EvtParticle.hh"
41#include "EvtGenBase/EvtGenKine.hh"
42#include "EvtGenBase/EvtPDL.hh"
43#include "EvtGenBase/EvtReport.hh"
44using std::endl;
45
46
47EvtBtoXsgammaAliGreub::~EvtBtoXsgammaAliGreub(){}
48
49void EvtBtoXsgammaAliGreub::init(int nArg, double* /*args*/){
50
51 if ((nArg - 1) != 0) {
52
53 report(ERROR,"EvtGen") << "EvtBtoXsgamma generator model "
54 << "EvtBtoXsgammaAliGreub expected "
55 << "zero arguments but found: "<<nArg-1<<endl;
56 report(ERROR,"EvtGen") << "Will terminate execution!"<<endl;
57 ::abort();
58
59 }
60
61}
62
63double EvtBtoXsgammaAliGreub::GetMass(int Xscode) {
64
65 // The special lineshape for strange hadrons X_s in b -> s gamma:
66 // An 18 parameter function fitted to the theoretical mass spectrum
67 // of Ali & Greub for a B meson mass of 5.279 GeV; top quark mass of
68 // 174.3 GeV; strange quark mass of 0.48 GeV (tuned to give minimum
69 // M_Xs of 0.64 GeV) and Fermi momentum of 265 MeV for spectator quark
70 // mass of 150 MeV (from CLEO fit). Truncated at max on high side
71 // and min (just above K pi or KK thresold) on low side.
72 double min=0.64;
73 double max=4.5;
74 double xbox, ybox, alifit;
75 double mass=0.0;
76
77 double par[18];
78 if ((Xscode == 30343) || (Xscode == -30343) ||
79 (Xscode == 30353) || (Xscode == -30353)) { // Xsu or Xsd
80 min=0.6373; // Just above K pi threshold for Xsd/u
81 //min=0.6333; // K pi threshold for neutral Xsd
82 par[0]=-2057.2380371094;
83 par[1]=2502.2556152344;
84 par[2]=1151.5632324219;
85 par[3]=0.82431584596634;
86 par[4]=-4110.5234375000;
87 par[5]=8445.6757812500;
88 par[6]=-3034.1894531250;
89 par[7]=1.1557708978653;
90 par[8]=1765.9311523438;
91 par[9]=1.3730158805847;
92 par[10]=0.51371538639069;
93 par[11]=2.0056934356689;
94 par[12]=37144.097656250;
95 par[13]=-50296.781250000;
96 par[14]=27319.095703125;
97 par[15]=-7408.0678710938;
98 par[16]=1000.8093261719;
99 par[17]=-53.834449768066;
100 } else if ((Xscode == 30363) || (Xscode == -30363)) {
101 min = 0.9964; // Just above KK threshold for Xss
102 par[0]=-32263.908203125;
103 par[1]=57186.589843750;
104 par[2]=-24230.728515625;
105 par[3]=1.1155973672867;
106 par[4]=-12161.131835938;
107 par[5]=20162.146484375;
108 par[6]=-7198.8564453125;
109 par[7]=1.3783323764801;
110 par[8]=1995.1691894531;
111 par[9]=1.4655895233154;
112 par[10]=0.48869228363037;
113 par[11]=2.1038570404053;
114 par[12]=55100.058593750;
115 par[13]=-75201.703125000;
116 par[14]=41096.066406250;
117 par[15]=-11205.986328125;
118 par[16]=1522.4024658203;
119 par[17]=-82.379623413086;
120 } else {
121 report(DEBUG,"EvtGen") << "In EvtBtoXsgammaAliGreub: Particle with id " << Xscode << " is not a Xss particle"<<endl;
122 return 0;
123 }
124
125 double boxheight=par[8];
126 double boxwidth=max-min;
127
128 while ((mass > max) || (mass < min)){
129 xbox = EvtRandom::Flat(boxwidth)+min;
130 ybox=EvtRandom::Flat(boxheight);
131 if (xbox<par[3]) {
132 alifit=par[0]+par[1]*xbox+par[2]*pow(xbox,2);
133 } else if (xbox<par[7]) {
134 alifit=par[4]+par[5]*xbox+par[6]*pow(xbox,2);
135 } else if (xbox<par[11]) {
136 alifit=par[8]*exp(-0.5*pow((xbox-par[9])/par[10],2));
137 } else {
138 alifit=par[12]+par[13]*xbox+par[14]*pow(xbox,2)+par[15]*pow(xbox,3)+par[16]*pow(xbox,4)+par[17]*pow(xbox,5);
139 }
140 if (ybox>alifit) {
141 mass=0.0;
142 } else {
143 mass=xbox;
144 }
145 }
146 return mass;
147}