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EvtSVVHelCPMix.cpp
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EvtSVVHelCPMix.cpp
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//--------------------------------------------------------------------------
//
// Environment:
// This software is part of the EvtGen package developed jointly
// for the BaBar and CLEO collaborations. If you use all or part
// of it, please give an appropriate acknowledgement.
//
// Copyright Information: See EvtGen/COPYRIGHT
// Copyright (C) 1998 Caltech, UCSB
//
// Module: EvtSVVHelCPMix.cc
//
// Description: Routine to decay scalar -> 2 vectors
// by specifying the helicity amplitudes, taking appropriate
// weak phases into account to get mixing and CP violation through
// interference. Based on EvtSVVHelAmp. Particularly appropriate for
// Bs->J/Psi+Phi
//
// Modification history:
//
// RYD November 24, 1996 EvtSVVHelAmp Module
// CATMORE March 2004 Modified to EvtSVVHelCPMix
//
// Model takes the following as user-specified arguments:
// deltaM, averageM - mass diference and average of light and heavy mass eigenstates (real scalars)
// gamma, deltagamma - average width and width difference of the l and h eigenstates (real scalars)
// delta1, delta2 - strong phases (real scalars)
// direct weak phase (real scalar) (for Bs->JPsiPhi this will be zero)
// weak mixing phase (real scalar) (this is equal to 2*arg(Vts Vtb) for Bs->JPsiPhi)
// Magnitudes of helicity amplitudes as in SVV_HELAMP
// See Phys Rev D 34 p1404 - p1417 and chapters 5 and 7 of Physics Reports 370 p537-680 for more details
//------------------------------------------------------------------------
//
#ifdef WIN32
#pragma warning( disable : 4786 )
// Disable anoying warning about symbol size
#endif
#include <iostream>
#include <fstream>
#include <stdlib.h>
#include <ctype.h>
#include "EvtGenBase/EvtParticle.hh"
#include "EvtGenBase/EvtGenKine.hh"
#include "EvtGenBase/EvtPDL.hh"
#include "EvtGenBase/EvtVector4C.hh"
#include "EvtGenBase/EvtTensor4C.hh"
#include "EvtGenBase/EvtVector3C.hh"
#include "EvtGenBase/EvtVector3R.hh"
#include "EvtGenBase/EvtTensor3C.hh"
#include "EvtGenBase/EvtReport.hh"
#include "EvtGenModels/EvtSVVHelCPMix.hh"
#include "EvtGenBase/EvtId.hh"
#include <string>
EvtSVVHelCPMix::~EvtSVVHelCPMix() {}
std::string EvtSVVHelCPMix::getName(){
return "SVVHELCPMIX";
}
EvtDecayBase* EvtSVVHelCPMix::clone(){
return new EvtSVVHelCPMix;
}
void EvtSVVHelCPMix::init(){
// check that there are 12 arguments
checkNArg(12);
checkNDaug(2);
checkSpinParent(EvtSpinType::SCALAR);
checkSpinDaughter(0,EvtSpinType::VECTOR);
checkSpinDaughter(1,EvtSpinType::VECTOR);
hp = EvtComplex(getArg(0)*cos(getArg(1)),getArg(0)*sin(getArg(1)));
h0 = EvtComplex(getArg(2)*cos(getArg(3)),getArg(2)*sin(getArg(3)));
hm = EvtComplex(getArg(4)*cos(getArg(5)),getArg(4)*sin(getArg(5)));
averageM = getArg(6);
deltaM = getArg(7);
gamma = getArg(8);
deltagamma = getArg(9);
weakmixingphase = EvtComplex(cos(getArg(10)),sin(getArg(10)));
weakdirectphase = EvtComplex(cos(getArg(11)),sin(getArg(11)));
}
void EvtSVVHelCPMix::initProbMax(){
setProbMax(getArg(0)*getArg(0)+getArg(2)*getArg(2)+getArg(4)*getArg(4));
}
void EvtSVVHelCPMix::decay( EvtParticle *p){
EvtParticle* parent = p;
EvtAmp& amp = _amp2;
EvtId n_v1 = getDaug(0);
EvtId n_v2 = getDaug(1);
// Routine to decay a vector into a vector and scalar. Started
// by ryd on Oct 17, 1996.
// Modified by J.Catmore to take account of CP-violation and mixing
int tndaug = 2;
EvtId tdaug[2];
EvtId Bs=EvtPDL::getId("B_s0");
EvtId antiBs=EvtPDL::getId("anti-B_s0");
tdaug[0] = n_v1;
tdaug[1] = n_v2;
// Phase space and kinematics
parent->initializePhaseSpace(tndaug,tdaug);
EvtParticle *v1,*v2;
v1 = parent->getDaug(0);
v2 = parent->getDaug(1);
EvtVector4R momv1 = v1->getP4();
EvtVector3R v1dir(momv1.get(1),momv1.get(2),momv1.get(3));
v1dir=v1dir/v1dir.d3mag();
// Definition of quantities used in construction of complex amplitudes:
EvtTensor3C M; // Tensor as defined in EvtGen manual, equ 117
EvtComplex a,b,c; // Helicity amplitudes; EvtGen manual eqns 126-128, also see Phys Lett B 369 p144-150 eqn 15
//EvtComplex deltamu = EvtComplex(deltaM, -0.5*deltagamma); // See Phys Rev D 34 p1404
// conversion from times in mm/c to natural units [GeV]^-1
double t = ((parent->getLifetime())/2.998e11)*6.58e-25;
// The following two quantities defined in Phys Rev D 34 p1404
EvtComplex fplus = EvtComplex(cos(averageM*t),-1.*sin(averageM*t))*exp(-(gamma/2.0)*t)*
(cos(0.5*deltaM*t)*cosh(0.25*deltagamma*t)+EvtComplex(0.0,sin(0.5*deltaM*t)*sinh(0.25*deltagamma*t)));
EvtComplex fminus = EvtComplex(cos(averageM*t), -1.*sin(averageM*t))*exp(-(gamma/2.0)*t)*EvtComplex(0.0,1.0)*
(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));
// See EvtGen manual pp 106-107
a=-0.5*(hp+hm);
b=EvtComplex(0.0,0.5)*(hp-hm);
c=(h0+0.5*(hp+hm));
M=a*EvtTensor3C::id()+
b*EvtGenFunctions::eps(v1dir)+
c*EvtGenFunctions::directProd(v1dir,v1dir);
EvtVector3C t0=M.cont1(v1->eps(0).vec().conj());
EvtVector3C t1=M.cont1(v1->eps(1).vec().conj());
EvtVector3C t2=M.cont1(v1->eps(2).vec().conj());
EvtVector3C eps0=v2->eps(0).vec().conj();
EvtVector3C eps1=v2->eps(1).vec().conj();
EvtVector3C eps2=v2->eps(2).vec().conj();
// We need two sets of equations, one for mesons which were in the Bs state at t=0, and another
// for those which were in the antiBs state. Each equation consists of a sum of amplitudes - mod-squaring gives the interference terms.
EvtComplex amplSum00, amplSum01, amplSum02;
EvtComplex amplSum10, amplSum11, amplSum12;
EvtComplex amplSum20, amplSum21, amplSum22;
// First the Bs state:
if (parent->getId()==Bs) {
amplSum00 = (fplus*weakdirectphase*t0*eps0) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t0*eps0);
amplSum01 = (fplus*weakdirectphase*t0*eps1) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t0*eps1);
amplSum02 = (fplus*weakdirectphase*t0*eps2) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t0*eps2);
amplSum10 = (fplus*weakdirectphase*t1*eps0) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t1*eps0);
amplSum11 = (fplus*weakdirectphase*t1*eps1) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t1*eps1);
amplSum12 = (fplus*weakdirectphase*t1*eps2) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t1*eps2);
amplSum20 = (fplus*weakdirectphase*t2*eps0) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t2*eps0);
amplSum21 = (fplus*weakdirectphase*t2*eps1) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t2*eps1);
amplSum22 = (fplus*weakdirectphase*t2*eps2) + (fminus*(1.0/weakdirectphase)*weakmixingphase*t2*eps2);
}
// Now the anti-Bs state:
if (parent->getId()==antiBs) {
amplSum00 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t0*eps0) + (fplus*(1.0/weakdirectphase)*t0*eps0);
amplSum01 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t0*eps1) + (fplus*(1.0/weakdirectphase)*t0*eps1);
amplSum02 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t0*eps2) + (fplus*(1.0/weakdirectphase)*t0*eps2);
amplSum10 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t1*eps0) + (fplus*(1.0/weakdirectphase)*t1*eps0);
amplSum11 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t1*eps1) + (fplus*(1.0/weakdirectphase)*t1*eps1);
amplSum12 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t1*eps2) + (fplus*(1.0/weakdirectphase)*t1*eps2);
amplSum20 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t2*eps0) + (fplus*(1.0/weakdirectphase)*t2*eps0);
amplSum21 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t2*eps1) + (fplus*(1.0/weakdirectphase)*t2*eps1);
amplSum22 = (fminus*weakdirectphase*(1.0/weakmixingphase)*t2*eps2) + (fplus*(1.0/weakdirectphase)*t2*eps2);
}
// Now set the amplitude
amp.vertex(0,0,amplSum00);
report(INFO,"EvtGen") << "00: " << amplSum00 << std::endl;
amp.vertex(0,1,amplSum01);
report(INFO,"EvtGen") << "01: " << amplSum01 << std::endl;
amp.vertex(0,2,amplSum02);
report(INFO,"EvtGen") << "02: " << amplSum02 << std::endl;
amp.vertex(1,0,amplSum10);
report(INFO,"EvtGen") << "10: " << amplSum10 << std::endl;
amp.vertex(1,1,amplSum11);
report(INFO,"EvtGen") << "11: " << amplSum11 << std::endl;
amp.vertex(1,2,amplSum12);
report(INFO,"EvtGen") << "12: " << amplSum12 << std::endl;
amp.vertex(2,0,amplSum20);
report(INFO,"EvtGen") << "20: " << amplSum20 << std::endl;
amp.vertex(2,1,amplSum21);
report(INFO,"EvtGen") << "21: " << amplSum21 << std::endl;
amp.vertex(2,2,amplSum22);
report(INFO,"EvtGen") << "22: " << amplSum22 << std::endl;
return ;
}
std::string EvtSVVHelCPMix::getParamName(int i) {
switch(i) {
case 0:
return "plusHelAmp";
case 1:
return "plusHelAmpPhase";
case 2:
return "zeroHelAmp";
case 3:
return "zeroHelAmpPhase";
case 4:
return "minusHelAmp";
case 5:
return "minusHelAmpPhase";
case 6:
return "averageM";
case 7:
return "deltaM";
case 8:
return "gamma";
case 9:
return "deltaGamma";
case 10:
return "weakMixPhase";
case 11:
return "weakDirectPhase";
default:
return "";
}
}
std::string EvtSVVHelCPMix::getParamDefault(int i) {
switch(i) {
case 0:
return "1.0";
case 1:
return "0.0";
case 2:
return "1.0";
case 3:
return "0.0";
case 4:
return "1.0";
case 5:
return "0.0";
default:
return "";
}
}

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