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da0e9ce3 | 1 | //-------------------------------------------------------------------------- |
2 | // | |
3 | // Environment: | |
4 | // This software is part of the EvtGen package developed jointly | |
5 | // for the BaBar and CLEO collaborations. If you use all or part | |
6 | // of it, please give an appropriate acknowledgement. | |
7 | // | |
8 | // Copyright Information: See EvtGen/COPYRIGHT | |
9 | // Copyright (C) 1998 Caltech, UCSB | |
10 | // | |
11 | // Module: EvtGen/EvtVubNLO.hh | |
12 | // | |
13 | // Description: | |
14 | // Class to generate inclusive B to X_u l nu decays according to various | |
15 | // decay models. Implemtented are ACCM, parton-model and a QCD model. | |
16 | // | |
17 | // Modification history: | |
18 | // | |
19 | // Sven Menke January 17, 2001 Module created | |
20 | // | |
21 | //------------------------------------------------------------------------ | |
22 | ||
23 | #ifndef EVTVUBNLO_HH | |
24 | #define EVTVUBNLO_HH | |
25 | ||
26 | #include <vector> | |
27 | #include "EvtGenBase/EvtDecayIncoherent.hh" | |
28 | ||
29 | class EvtParticle; | |
30 | class RandGeneral; | |
31 | ||
32 | class EvtVubNLO:public EvtDecayIncoherent { | |
33 | ||
34 | public: | |
35 | ||
36 | EvtVubNLO() {} | |
37 | virtual ~EvtVubNLO(); | |
38 | ||
39 | std::string getName(); | |
40 | ||
41 | EvtDecayBase* clone(); | |
42 | ||
43 | void initProbMax(); | |
44 | ||
45 | void init(); | |
46 | ||
47 | void decay(EvtParticle *p); | |
48 | ||
49 | ||
50 | private: | |
51 | ||
52 | // cache | |
53 | double _lbar; | |
54 | double _mupi2; | |
55 | ||
56 | double _mb; // the b-quark pole mass in GeV | |
57 | double _mB; | |
58 | double _lambdaSF; | |
59 | double _b; // Parameter for the Fermi Motion | |
60 | double _kpar; | |
61 | double _mui; // renormalization scale (preferred value=1.5 GeV) | |
62 | double _SFNorm; // SF normalization | |
63 | double _dGMax; // max dGamma*p2 value; | |
64 | int _nbins; | |
65 | int _idSF;// which shape function? | |
66 | double * _masses; | |
67 | double * _weights; | |
68 | ||
69 | double _gmax; | |
70 | int _ngood,_ntot; | |
71 | ||
72 | ||
73 | double tripleDiff(double pp, double pl, double pm); | |
74 | double SFNorm(const std::vector<double> &coeffs); | |
75 | static double integrand(double omega, const std::vector<double> &coeffs); | |
76 | double F10(const std::vector<double> &coeffs); | |
77 | static double F1Int(double omega,const std::vector<double> &coeffs); | |
78 | double F20(const std::vector<double> &coeffs); | |
79 | static double F2Int(double omega,const std::vector<double> &coeffs); | |
80 | double F30(const std::vector<double> &coeffs); | |
81 | static double F3Int(double omega,const std::vector<double> &coeffs); | |
82 | static double g1(double y, double z); | |
83 | static double g2(double y, double z); | |
84 | static double g3(double y, double z); | |
85 | ||
86 | static double Gamma(double z);// Euler Gamma Function | |
87 | static double dgamma(double t, const std::vector<double> &c){ return pow(t,c[0]-1)*exp(-t);} | |
88 | static double Gamma(double z, double tmax); | |
89 | ||
90 | // theory parameters | |
91 | inline double mu_i(){return _mui;} // intermediate scale | |
92 | inline double mu_bar(){return _mui;} | |
93 | inline double mu_h(){return _mb/sqrt(2.0);} // high scale | |
94 | inline double lambda1(){return -_mupi2;} | |
95 | ||
96 | // expansion coefficients for RGE | |
97 | static double beta0(int nf=4){return 11.-2./3.*nf;} | |
98 | static double beta1(int nf=4){return 34.*3.-38./3.*nf;} | |
99 | static double beta2(int nf=4){return 1428.5-5033./18.*nf+325./54.*nf*nf;} | |
100 | static double gamma0(){return 16./3.;} | |
101 | static double gamma1(int nf=4){return 4./3.*(49.85498-40./9.*nf);} | |
102 | static double gamma2(int nf=4){return 64./3.*(55.07242-8.58691*nf-nf*nf/27.);} /* zeta3=1.20206 */ | |
103 | static double gammap0(){return -20./3.;} | |
104 | static double gammap1(int nf=4){return -32./3.*(6.92653-0.9899*nf);} /* ?? zeta3=1.202 */ | |
105 | ||
106 | ||
107 | // running constants | |
108 | ||
109 | static double alphas(double mu) ; | |
110 | static double C_F(double mu){return (4.0/3.0)*alphas(mu)/4./EvtConst::pi;} | |
111 | ||
112 | // Shape Functions | |
113 | ||
114 | inline double lambda_SF(){ return _lambdaSF;} | |
115 | double lambda_bar(double omega0); | |
116 | inline double lambda2(){return 0.12;} | |
117 | double mu_pi2(double omega0); | |
118 | inline double lambda(double mu=0){ return _mB-_mb;} | |
119 | ||
120 | // specail for gaussian SF | |
121 | static double cGaus(double b){return pow(Gamma(1+b/2.)/Gamma((1+b)/2.),2);} | |
122 | ||
123 | double M0(double mui,double omega0); | |
124 | static double shapeFunction(double omega, const std::vector<double> &coeffs); | |
125 | static double expShapeFunction(double omega, const std::vector<double> &coeffs); | |
126 | static double gausShapeFunction(double omega, const std::vector<double> &coeffs); | |
127 | // SSF (not yet implemented) | |
128 | double subS(const std::vector<double> &coeffs ); | |
129 | double subT(const std::vector<double> &coeffs); | |
130 | double subU(const std::vector<double> &coeffs); | |
131 | double subV(const std::vector<double> &coeffs); | |
132 | ||
133 | ||
134 | // Sudakov | |
135 | ||
136 | inline double S0(double a, double r){return -gamma0()/4/a/pow(beta0(),2)*(1/r-1+log(r));} | |
137 | inline double S1(double a, double r){return gamma0()/4./pow(beta0(),2)*( | |
138 | pow(log(r),2)*beta1()/2./beta0()+(gamma1()/gamma0()-beta1()/beta0())*(1.-r+log(r)) | |
139 | );} | |
140 | inline double S2(double a, double r){return gamma0()*a/4./pow(beta0(),2)*( | |
141 | -0.5*pow((1-r),2)*( | |
142 | pow(beta1()/beta0(),2)-beta2()/beta0()-beta1()/beta0()*gamma1()/gamma0()+gamma2()/gamma0() | |
143 | ) | |
144 | +(pow(beta1()/beta0(),2)-beta2()/beta0())*(1-r)*log(r) | |
145 | +(beta1()/beta0()*gamma1()/gamma0()-beta2()/beta0())*(1-r+r*log(r)) | |
146 | );} | |
147 | inline double dSudakovdepsi(double mu1, double mu2){return S2(alphas(mu1)/(4*EvtConst::pi),alphas(mu2)/alphas(mu1));} | |
148 | inline double Sudakov(double mu1, double mu2, double epsi=0){double fp(4*EvtConst::pi);return S0(alphas(mu1)/fp,alphas(mu2)/alphas(mu1))+S1(alphas(mu1)/fp,alphas(mu2)/alphas(mu1))+epsi*dSudakovdepsi(mu1,mu2);} | |
149 | ||
150 | // RG | |
151 | inline double dGdepsi(double mu1, double mu2){return 1./8./EvtConst::pi*(alphas(mu2)-alphas(mu1))*(gamma1()/beta0()-beta1()*gamma0()/pow(beta0(),2));} | |
152 | inline double aGamma(double mu1, double mu2, double epsi=0){return gamma0()/2/beta0()*log(alphas(mu2)/alphas(mu1))+epsi*dGdepsi( mu1, mu2);} | |
153 | inline double dgpdepsi(double mu1, double mu2){return 1./8./EvtConst::pi*(alphas(mu2)-alphas(mu1))*(gammap1()/beta0()-beta1()*gammap0()/pow(beta0(),2));} | |
154 | inline double agammap(double mu1, double mu2, double epsi=0){return gammap0()/2/beta0()*log(alphas(mu2)/alphas(mu1))+epsi*dgpdepsi( mu1, mu2);} | |
155 | inline double U1(double mu1, double mu2, double epsi=0){return exp(2*(Sudakov(mu1,mu2,epsi)-agammap(mu1,mu2,epsi)-aGamma(mu1,mu2,epsi)*log(_mb/mu1)));} | |
156 | inline double U1lo(double mu1, double mu2){return U1(mu1,mu2);} | |
157 | inline double U1nlo(double mu1, double mu2){return U1(mu1,mu2)*(1+2*(dSudakovdepsi(mu1,mu2)-dgpdepsi( mu1, mu2)-log(_mb/mu1)*dGdepsi( mu1, mu2)));} | |
158 | inline double alo(double mu1, double mu2){return -2*aGamma(mu1,mu2);} | |
159 | inline double anlo(double mu1, double mu2){return -2*dGdepsi(mu1,mu2);} | |
160 | ||
161 | }; | |
162 | ||
163 | #endif | |
164 |