1 //--------------------------------------------------------------------------
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.
8 // Copyright Information: See EvtGen/COPYRIGHT
9 // Copyright (C) 2000 Caltech, UCSB
11 // Module: EvtbTosllVectorAmp.cc
13 // Description: Routine to implement bTosll decays to vector
16 // Modification history:
18 // Ryd January 5,2000 Module created
20 //------------------------------------------------------------------------
22 #include "EvtGenBase/EvtPatches.hh"
23 #include "EvtGenBase/EvtPatches.hh"
24 #include "EvtGenBase/EvtParticle.hh"
25 #include "EvtGenBase/EvtGenKine.hh"
26 #include "EvtGenBase/EvtPDL.hh"
27 #include "EvtGenBase/EvtReport.hh"
28 #include "EvtGenBase/EvtVector4C.hh"
29 #include "EvtGenBase/EvtTensor4C.hh"
30 #include "EvtGenBase/EvtDiracSpinor.hh"
31 #include "EvtGenModels/EvtbTosllVectorAmp.hh"
32 #include "EvtGenBase/EvtId.hh"
33 #include "EvtGenBase/EvtIdSet.hh"
34 #include "EvtGenBase/EvtAmp.hh"
35 #include "EvtGenModels/EvtbTosllAmp.hh"
36 #include "EvtGenModels/EvtbTosllFF.hh"
38 void EvtbTosllVectorAmp::CalcAmp( EvtParticle *parent,
40 EvtbTosllFF *formFactors ) {
42 //Add the lepton and neutrino 4 momenta to find q2
44 EvtVector4R q = parent->getDaug(1)->getP4()
45 + parent->getDaug(2)->getP4();
46 double q2 = (q.mass2());
49 double a1,a2,a0,v,t1,t2,t3;
50 double mesonmass = parent->getDaug(0)->mass();
51 double parentmass = parent->mass();
53 formFactors->getVectorFF(parent->getId(),
54 parent->getDaug(0)->getId(),
60 EvtId daught = parent->getDaug(0)->getId();
65 daught == EvtPDL::getId(std::string("rho+")) ||
66 daught == EvtPDL::getId(std::string("rho-")) ||
67 daught == EvtPDL::getId(std::string("rho0")) ||
68 daught == EvtPDL::getId(std::string("omega"))
73 p4b.set(parent->mass(),0.0,0.0,0.0);
74 EvtVector4R p4meson = parent->getDaug(0)->getP4();
82 EvtId parentID = parent->getId();
84 //EvtId l_num = parent->getDaug(1)->getId();
86 EvtVector4R pbhat=p4b/parentmass;
87 EvtVector4R qhat=q/parentmass;
88 EvtVector4R pkstarhat=p4meson/parentmass;
89 EvtVector4R phat=pbhat+pkstarhat;
91 EvtComplex c7eff = EvtbTosllAmp::GetC7Eff(q2,nnlo);
92 EvtComplex c9eff = EvtbTosllAmp::GetC9Eff(q2,nnlo,btod);
93 EvtComplex c10eff = EvtbTosllAmp::GetC10Eff(q2,nnlo);
94 EvtComplex uniti(0.0,1.0);
96 double mhatb=4.4/(parentmass);
97 double mhatkstar=mesonmass/(parentmass);
98 double shat=q2/(parentmass*parentmass);
102 a=c9eff*v*2/(1+mhatkstar)+4*mhatb*c7eff*t1/shat;
104 b=(1+mhatkstar)*(c9eff*a1+2*mhatb*(1-mhatkstar)*c7eff*t2/shat);
106 c=((1-mhatkstar)*c9eff*a2+
107 2*mhatb*c7eff*(t3+(1-mhatkstar*mhatkstar)*t2/shat))/
108 (1-mhatkstar*mhatkstar);
110 d=(c9eff*((1+mhatkstar)*a1-(1-mhatkstar)*a2-2*mhatkstar*a0)
111 -2*mhatb*c7eff*t3)/shat;
113 e=2*c10eff*v/(1+mhatkstar);
115 f=(1+mhatkstar)*c10eff*a1;
117 g=c10eff*a2/(1+mhatkstar);
119 h=c10eff*((1+mhatkstar)*a1-(1-mhatkstar)*a2-2*mhatkstar*a0)/shat;
123 static EvtIdSet bmesons("B-","anti-B0","anti-B_s0");
124 static EvtIdSet bbarmesons("B+","B0","B_s0");
126 EvtParticle* lepPlus=0;
127 EvtParticle* lepMinus=0;
129 int charge1 = EvtPDL::chg3(parent->getDaug(1)->getId());
130 int charge2 = EvtPDL::chg3(parent->getDaug(2)->getId());
132 lepPlus = (charge1 > charge2) ? parent->getDaug(1) : parent->getDaug(2);
133 lepMinus = (charge1 < charge2) ? parent->getDaug(1) : parent->getDaug(2);
135 if (bmesons.contains(parentID)) {
137 T1=a*dual(directProd(pbhat,pkstarhat))
138 -b*uniti*EvtTensor4C::g()
139 +c*uniti*directProd(pbhat,phat)
140 +d*uniti*directProd(pbhat,qhat);
142 T2=e*dual(directProd(pbhat,pkstarhat))
143 -f*uniti*EvtTensor4C::g()
144 +g*uniti*directProd(pbhat,phat)
145 +h*uniti*directProd(pbhat,qhat);
147 l11=EvtLeptonVCurrent(lepPlus->spParent(0),
148 lepMinus->spParent(0));
149 l21=EvtLeptonVCurrent(lepPlus->spParent(1),
150 lepMinus->spParent(0));
151 l12=EvtLeptonVCurrent(lepPlus->spParent(0),
152 lepMinus->spParent(1));
153 l22=EvtLeptonVCurrent(lepPlus->spParent(1),
154 lepMinus->spParent(1));
156 a11=EvtLeptonACurrent(lepPlus->spParent(0),
157 lepMinus->spParent(0));
158 a21=EvtLeptonACurrent(lepPlus->spParent(1),
159 lepMinus->spParent(0));
160 a12=EvtLeptonACurrent(lepPlus->spParent(0),
161 lepMinus->spParent(1));
162 a22=EvtLeptonACurrent(lepPlus->spParent(1),
163 lepMinus->spParent(1));
167 if (bbarmesons.contains(parentID)) {
169 T1=-a*dual(directProd(pbhat,pkstarhat))
170 -b*uniti*EvtTensor4C::g()
171 +c*uniti*directProd(pbhat,phat)
172 +d*uniti*directProd(pbhat,qhat);
174 T2=-e*dual(directProd(pbhat,pkstarhat))
175 -f*uniti*EvtTensor4C::g()
176 +g*uniti*directProd(pbhat,phat)
177 +h*uniti*directProd(pbhat,qhat);
179 l11=EvtLeptonVCurrent(lepPlus->spParent(1),
180 lepMinus->spParent(1));
181 l21=EvtLeptonVCurrent(lepPlus->spParent(0),
182 lepMinus->spParent(1));
183 l12=EvtLeptonVCurrent(lepPlus->spParent(1),
184 lepMinus->spParent(0));
185 l22=EvtLeptonVCurrent(lepPlus->spParent(0),
186 lepMinus->spParent(0));
188 a11=EvtLeptonACurrent(lepPlus->spParent(1),
189 lepMinus->spParent(1));
190 a21=EvtLeptonACurrent(lepPlus->spParent(0),
191 lepMinus->spParent(1));
192 a12=EvtLeptonACurrent(lepPlus->spParent(1),
193 lepMinus->spParent(0));
194 a22=EvtLeptonACurrent(lepPlus->spParent(0),
195 lepMinus->spParent(0));
199 report(ERROR,"EvtGen") << "Wrong lepton number\n";
207 EvtVector4C eps=parent->getDaug(0)->epsParent(i).conj();
209 EvtVector4C E1=T1.cont1(eps);
210 EvtVector4C E2=T2.cont1(eps);
212 amp.vertex(i,0,0,l11*E1+a11*E2);
213 amp.vertex(i,0,1,l12*E1+a12*E2);
214 amp.vertex(i,1,0,l21*E1+a21*E2);
215 amp.vertex(i,1,1,l22*E1+a22*E2);