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) 1998 Caltech, UCSB
11 // Module: EvtSVVHelCPMix.cc
13 // Description: Routine to decay scalar -> 2 vectors
14 // by specifying the helicity amplitudes, taking appropriate
15 // weak phases into account to get mixing and CP violation through
16 // interference. Based on EvtSVVHelAmp. Particularly appropriate for
19 // Modification history:
21 // RYD November 24, 1996 EvtSVVHelAmp Module
22 // CATMORE March 2004 Modified to EvtSVVHelCPMix
24 // Model takes the following as user-specified arguments:
25 // deltaM, averageM - mass diference and average of light and heavy mass eigenstates (real scalars)
26 // gamma, deltagamma - average width and width difference of the l and h eigenstates (real scalars)
27 // delta1, delta2 - strong phases (real scalars)
28 // direct weak phase (real scalar) (for Bs->JPsiPhi this will be zero)
29 // weak mixing phase (real scalar) (this is equal to 2*arg(Vts Vtb) for Bs->JPsiPhi)
30 // Magnitudes of helicity amplitudes as in SVV_HELAMP
31 // See Phys Rev D 34 p1404 - p1417 and chapters 5 and 7 of Physics Reports 370 p537-680 for more details
32 //------------------------------------------------------------------------
35 #pragma warning( disable : 4786 )
36 // Disable anoying warning about symbol size
42 #include "EvtGenBase/EvtParticle.hh"
43 #include "EvtGenBase/EvtGenKine.hh"
44 #include "EvtGenBase/EvtPDL.hh"
45 #include "EvtGenBase/EvtVector4C.hh"
46 #include "EvtGenBase/EvtTensor4C.hh"
47 #include "EvtGenBase/EvtVector3C.hh"
48 #include "EvtGenBase/EvtVector3R.hh"
49 #include "EvtGenBase/EvtTensor3C.hh"
50 #include "EvtGenBase/EvtReport.hh"
51 #include "EvtGenModels/EvtSVVHelCPMix.hh"
52 #include "EvtGenBase/EvtId.hh"
55 EvtSVVHelCPMix::~EvtSVVHelCPMix() {}
57 std::string EvtSVVHelCPMix::getName(){
64 EvtDecayBase* EvtSVVHelCPMix::clone(){
66 return new EvtSVVHelCPMix;
70 void EvtSVVHelCPMix::init(){
72 // check that there are 12 arguments
76 checkSpinParent(EvtSpinType::SCALAR);
78 checkSpinDaughter(0,EvtSpinType::VECTOR);
79 checkSpinDaughter(1,EvtSpinType::VECTOR);
81 hp = EvtComplex(getArg(0)*cos(getArg(1)),getArg(0)*sin(getArg(1)));
82 h0 = EvtComplex(getArg(2)*cos(getArg(3)),getArg(2)*sin(getArg(3)));
83 hm = EvtComplex(getArg(4)*cos(getArg(5)),getArg(4)*sin(getArg(5)));
87 deltagamma = getArg(9);
88 weakmixingphase = EvtComplex(cos(getArg(10)),sin(getArg(10)));
89 weakdirectphase = EvtComplex(cos(getArg(11)),sin(getArg(11)));
93 void EvtSVVHelCPMix::initProbMax(){
95 setProbMax(getArg(0)*getArg(0)+getArg(2)*getArg(2)+getArg(4)*getArg(4));
100 void EvtSVVHelCPMix::decay( EvtParticle *p){
102 EvtParticle* parent = p;
104 EvtId n_v1 = getDaug(0);
105 EvtId n_v2 = getDaug(1);
107 // Routine to decay a vector into a vector and scalar. Started
108 // by ryd on Oct 17, 1996.
109 // Modified by J.Catmore to take account of CP-violation and mixing
113 EvtId Bs=EvtPDL::getId("B_s0");
114 EvtId antiBs=EvtPDL::getId("anti-B_s0");
118 // Phase space and kinematics
120 parent->initializePhaseSpace(tndaug,tdaug);
123 v1 = parent->getDaug(0);
124 v2 = parent->getDaug(1);
126 EvtVector4R momv1 = v1->getP4();
127 EvtVector4R momv2 = v2->getP4();
129 EvtVector3R v1dir(momv1.get(1),momv1.get(2),momv1.get(3));
130 v1dir=v1dir/v1dir.d3mag();
132 // Definition of quantities used in construction of complex amplitudes:
134 EvtTensor3C M; // Tensor as defined in EvtGen manual, equ 117
135 EvtComplex a,b,c; // Helicity amplitudes; EvtGen manual eqns 126-128, also see Phys Lett B 369 p144-150 eqn 15
136 EvtComplex deltamu = EvtComplex(deltaM, -0.5*deltagamma); // See Phys Rev D 34 p1404
138 // conversion from times in mm/c to natural units [GeV]^-1
139 double t = ((parent->getLifetime())/2.998e11)*6.58e-25;
141 // The following two quantities defined in Phys Rev D 34 p1404
142 EvtComplex fplus = EvtComplex(cos(averageM*t),-1.*sin(averageM*t))*exp(-(gamma/2.0)*t)*
143 (cos(0.5*deltaM*t)*cosh(0.25*deltagamma*t)+EvtComplex(0.0,sin(0.5*deltaM*t)*sinh(0.25*deltagamma*t)));
144 EvtComplex fminus = EvtComplex(cos(averageM*t), -1.*sin(averageM*t))*exp(-(gamma/2.0)*t)*EvtComplex(0.0,1.0)*
145 (sin(0.5*deltaM*t)*cosh(0.25*deltagamma*t)-EvtComplex(0.0,1.0)*sinh(0.25*deltagamma*t)*cos(0.5*deltaM*t));
147 // See EvtGen manual pp 106-107
150 b=EvtComplex(0.0,0.5)*(hp-hm);
153 M=a*EvtTensor3C::id()+
155 c*directProd(v1dir,v1dir);
157 EvtVector3C t0=M.cont1(v1->eps(0).vec().conj());
158 EvtVector3C t1=M.cont1(v1->eps(1).vec().conj());
159 EvtVector3C t2=M.cont1(v1->eps(2).vec().conj());
161 EvtVector3C eps0=v2->eps(0).vec().conj();
162 EvtVector3C eps1=v2->eps(1).vec().conj();
163 EvtVector3C eps2=v2->eps(2).vec().conj();
165 // We need two sets of equations, one for mesons which were in the Bs state at t=0, and another
166 // for those which were in the antiBs state. Each equation consists of a sum of amplitudes - mod-squaring gives the interference terms.
168 EvtComplex amplSum00, amplSum01, amplSum02;
169 EvtComplex amplSum10, amplSum11, amplSum12;
170 EvtComplex amplSum20, amplSum21, amplSum22;
172 // First the Bs state:
174 if (parent->getId()==Bs) {
176 amplSum00 = (fplus*weakdirectphase*t0*eps0) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t0*eps0);
177 amplSum01 = (fplus*weakdirectphase*t0*eps1) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t0*eps1);
178 amplSum02 = (fplus*weakdirectphase*t0*eps2) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t0*eps2);
180 amplSum10 = (fplus*weakdirectphase*t1*eps0) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t1*eps0);
181 amplSum11 = (fplus*weakdirectphase*t1*eps1) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t1*eps1);
182 amplSum12 = (fplus*weakdirectphase*t1*eps2) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t1*eps2);
184 amplSum20 = (fplus*weakdirectphase*t2*eps0) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t2*eps0);
185 amplSum21 = (fplus*weakdirectphase*t2*eps1) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t2*eps1);
186 amplSum22 = (fplus*weakdirectphase*t2*eps2) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t2*eps2);
189 // Now the anti-Bs state:
191 if (parent->getId()==antiBs) {
193 amplSum00 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t0*eps0) + (fplus*(1.0/weakdirectphase)*t0*eps0);
194 amplSum01 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t0*eps1) + (fplus*(1.0/weakdirectphase)*t0*eps1);
195 amplSum02 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t0*eps2) + (fplus*(1.0/weakdirectphase)*t0*eps2);
197 amplSum10 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t1*eps0) + (fplus*(1.0/weakdirectphase)*t1*eps0);
198 amplSum11 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t1*eps1) + (fplus*(1.0/weakdirectphase)*t1*eps1);
199 amplSum12 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t1*eps2) + (fplus*(1.0/weakdirectphase)*t1*eps2);
201 amplSum20 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t2*eps0) + (fplus*(1.0/weakdirectphase)*t2*eps0);
202 amplSum21 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t2*eps1) + (fplus*(1.0/weakdirectphase)*t2*eps1);
203 amplSum22 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t2*eps2) + (fplus*(1.0/weakdirectphase)*t2*eps2);
207 // Now set the amplitude
209 amp.vertex(0,0,amplSum00);
210 report(INFO,"EvtGen") << "00: " << amplSum00 << std::endl;
211 amp.vertex(0,1,amplSum01);
212 report(INFO,"EvtGen") << "01: " << amplSum01 << std::endl;
213 amp.vertex(0,2,amplSum02);
214 report(INFO,"EvtGen") << "02: " << amplSum02 << std::endl;
216 amp.vertex(1,0,amplSum10);
217 report(INFO,"EvtGen") << "10: " << amplSum10 << std::endl;
218 amp.vertex(1,1,amplSum11);
219 report(INFO,"EvtGen") << "11: " << amplSum11 << std::endl;
220 amp.vertex(1,2,amplSum12);
221 report(INFO,"EvtGen") << "12: " << amplSum12 << std::endl;
223 amp.vertex(2,0,amplSum20);
224 report(INFO,"EvtGen") << "20: " << amplSum20 << std::endl;
225 amp.vertex(2,1,amplSum21);
226 report(INFO,"EvtGen") << "21: " << amplSum21 << std::endl;
227 amp.vertex(2,2,amplSum22);
228 report(INFO,"EvtGen") << "22: " << amplSum22 << std::endl;