EvtSemiLeptonicScalarAmp Class Reference

#include <EvtSemiLeptonicScalarAmp.hh>

Inheritance diagram for EvtSemiLeptonicScalarAmp:

EvtSemiLeptonicAmp List of all members.

Public Member Functions

double CalcMaxProb (EvtId parent, EvtId meson, EvtId lepton, EvtId nudaug, EvtSemiLeptonicFF *FormFactors)

Private Member Functions

void CalcAmp (EvtParticle *parent, EvtAmp &amp, EvtSemiLeptonicFF *FormFactors)

Detailed Description

Definition at line 30 of file EvtSemiLeptonicScalarAmp.hh.


Member Function Documentation

void EvtSemiLeptonicScalarAmp::CalcAmp ( EvtParticle parent,
EvtAmp amp,
EvtSemiLeptonicFF FormFactors 
) [private, virtual]

Reimplemented from EvtSemiLeptonicAmp.

Definition at line 36 of file EvtSemiLeptonicScalarAmp.cc.

References calibUtil::ERROR, EvtLeptonVACurrent(), EvtParticle::getDaug(), EvtParticle::getId(), EvtPDL::getId(), EvtParticle::getP4(), EvtSemiLeptonicFF::getscalarff(), EvtParticle::mass(), q, report(), EvtVector4R::set(), EvtParticle::spParent(), EvtParticle::spParentNeutrino(), and EvtAmp::vertex().

00038                                                                          {
00039 
00040   static EvtId EM=EvtPDL::getId("e-");
00041   static EvtId MUM=EvtPDL::getId("mu-");
00042   static EvtId TAUM=EvtPDL::getId("tau-");
00043   static EvtId EP=EvtPDL::getId("e+");
00044   static EvtId MUP=EvtPDL::getId("mu+");
00045   static EvtId TAUP=EvtPDL::getId("tau+");
00046   
00047   //Add the lepton and neutrino 4 momenta to find q2
00048 
00049   EvtVector4R q = parent->getDaug(1)->getP4() 
00050                     + parent->getDaug(2)->getP4();
00051   double q2 = (q.mass2());
00052 
00053   double fpf,f0f;
00054   double mesonmass = parent->getDaug(0)->mass();
00055   double parentmass = parent->mass();
00056 
00057   FormFactors->getscalarff(parent->getId(),
00058                            parent->getDaug(0)->getId(),
00059                            q2,
00060                            mesonmass,
00061                            &fpf, 
00062                            &f0f);
00063 
00064 
00065   EvtVector4R p4b;
00066   p4b.set(parent->mass(),0.0,0.0,0.0);
00067   EvtVector4R p4meson = parent->getDaug(0)->getP4();
00068   double mdiffoverq2;
00069   mdiffoverq2 = parentmass*parentmass - mesonmass*mesonmass;
00070   mdiffoverq2 = mdiffoverq2 / q2;
00071 
00072   EvtVector4C l1,l2;
00073 
00074   EvtId l_num = parent->getDaug(1)->getId();
00075   EvtVector4C tds;
00076 
00077   if (l_num==EM||l_num==MUM||l_num==TAUM){
00078 
00079     tds = EvtVector4C(fpf*(p4b+p4meson - (mdiffoverq2*(p4b-p4meson)))+
00080                     + f0f*mdiffoverq2*(p4b-p4meson));
00081 
00082     l1=EvtLeptonVACurrent(parent->getDaug(1)->spParent(0),
00083                           parent->getDaug(2)->spParentNeutrino());
00084     l2=EvtLeptonVACurrent(parent->getDaug(1)->spParent(1),
00085                           parent->getDaug(2)->spParentNeutrino());
00086   }
00087   else{
00088     if (l_num==EP||l_num==MUP||l_num==TAUP){
00089 
00090       tds = EvtVector4C(fpf*(p4b+p4meson - (mdiffoverq2*(p4b-p4meson)))+
00091                     + f0f*mdiffoverq2*(p4b-p4meson));
00092 
00093       l1=EvtLeptonVACurrent(parent->getDaug(2)->spParentNeutrino(),
00094                             parent->getDaug(1)->spParent(0));
00095       l2=EvtLeptonVACurrent(parent->getDaug(2)->spParentNeutrino(),
00096                             parent->getDaug(1)->spParent(1));
00097     }
00098     else{
00099       report(ERROR,"EvtGen") << "dfnb89agngri wrong lepton number\n";
00100     }
00101   }
00102 
00103   amp.vertex(0,l1*tds);
00104   amp.vertex(1,l2*tds);
00105 
00106 }

double EvtSemiLeptonicAmp::CalcMaxProb ( EvtId  parent,
EvtId  meson,
EvtId  lepton,
EvtId  nudaug,
EvtSemiLeptonicFF FormFactors 
) [inherited]

Definition at line 38 of file EvtSemiLeptonicAmp.cc.

References boostTo(), EvtSemiLeptonicAmp::CalcAmp(), EvtParticle::deleteTree(), EvtParticle::getDaug(), EvtPDL::getMass(), EvtPDL::getMaxMass(), EvtPDL::getMeanMass(), EvtPDL::getMinMass(), EvtAmp::getSpinDensity(), EvtParticle::getSpinStates(), EvtPDL::getWidth(), genRecEmupikp::i, EvtParticle::init(), EvtAmp::init(), EvtScalarParticle::init(), ganga-rec::j, EvtParticle::makeDaughters(), EvtParticle::mass(), mass, EvtParticle::noLifeTime(), EvtSpinDensity::NormalizedProb(), EvtVector4R::set(), EvtSpinDensity::SetDiag(), and EvtParticle::setDiagonalSpinDensity().

Referenced by EvtSLPole::initProbMax(), EvtSLBKPole::initProbMax(), EvtHQET2::initProbMax(), and EvtHQET::initProbMax().

00040                                                       {
00041 
00042   //This routine takes the arguements parent, meson, and lepton
00043   //number, and a form factor model, and returns a maximum
00044   //probability for this semileptonic form factor model.  A
00045   //brute force method is used.  The 2D cos theta lepton and
00046   //q2 phase space is probed.
00047 
00048   //Start by declaring a particle at rest.
00049 
00050   //It only makes sense to have a scalar parent.  For now. 
00051   //This should be generalized later.
00052 
00053   EvtScalarParticle *scalar_part;
00054   EvtParticle *root_part;
00055 
00056   scalar_part=new EvtScalarParticle;
00057 
00058   //cludge to avoid generating random numbers!
00059   scalar_part->noLifeTime();
00060 
00061   EvtVector4R p_init;
00062   
00063   p_init.set(EvtPDL::getMass(parent),0.0,0.0,0.0);
00064   scalar_part->init(parent,p_init);
00065   root_part=(EvtParticle *)scalar_part;
00066 //  root_part->set_type(EvtSpinType::SCALAR);
00067   root_part->setDiagonalSpinDensity();      
00068 
00069   EvtParticle *daughter, *lep, *trino;
00070   
00071   EvtAmp amp;
00072 
00073   EvtId listdaug[3];
00074   listdaug[0] = meson;
00075   listdaug[1] = lepton;
00076   listdaug[2] = nudaug;
00077 
00078   amp.init(parent,3,listdaug);
00079 
00080   root_part->makeDaughters(3,listdaug);
00081   daughter=root_part->getDaug(0);
00082   lep=root_part->getDaug(1);
00083   trino=root_part->getDaug(2);
00084 
00085   //cludge to avoid generating random numbers!
00086   daughter->noLifeTime();
00087   lep->noLifeTime();
00088   trino->noLifeTime();
00089 
00090 
00091   //Initial particle is unpolarized, well it is a scalar so it is 
00092   //trivial
00093   EvtSpinDensity rho;
00094   rho.SetDiag(root_part->getSpinStates());
00095   
00096   double mass[3];
00097   
00098   double m = root_part->mass();
00099   
00100   EvtVector4R p4meson, p4lepton, p4nu, p4w;
00101   double q2max;
00102 
00103   double q2, elepton, plepton;
00104   int i,j;
00105   double erho,prho,costl;
00106 
00107   double maxfoundprob = 0.0;
00108   double prob = -10.0;
00109   int massiter;
00110 
00111   for (massiter=0;massiter<3;massiter++){
00112 
00113     mass[0] = EvtPDL::getMeanMass(meson);
00114     mass[1] = EvtPDL::getMeanMass(lepton);
00115     mass[2] = EvtPDL::getMeanMass(nudaug);
00116     if ( massiter==1 ) {
00117       mass[0] = EvtPDL::getMinMass(meson);
00118     }
00119     if ( massiter==2 ) {
00120       mass[0] = EvtPDL::getMaxMass(meson);
00121       if ( (mass[0]+mass[1]+mass[2])>m) mass[0]=m-mass[1]-mass[2]-0.00001; 
00122     }
00123 
00124     q2max = (m-mass[0])*(m-mass[0]);
00125     
00126     //loop over q2
00127 
00128     for (i=0;i<25;i++) {
00129       q2 = ((i+0.5)*q2max)/25.0;
00130       
00131       erho = ( m*m + mass[0]*mass[0] - q2 )/(2.0*m);
00132       
00133       prho = sqrt(erho*erho-mass[0]*mass[0]);
00134       
00135       p4meson.set(erho,0.0,0.0,-1.0*prho);
00136       p4w.set(m-erho,0.0,0.0,prho);
00137       
00138       //This is in the W rest frame
00139       elepton = (q2+mass[1]*mass[1])/(2.0*sqrt(q2));
00140       plepton = sqrt(elepton*elepton-mass[1]*mass[1]);
00141       
00142       double probctl[3];
00143 
00144       for (j=0;j<3;j++) {
00145         
00146         costl = 0.99*(j - 1.0);
00147         
00148         //These are in the W rest frame. Need to boost out into
00149         //the B frame.
00150         p4lepton.set(elepton,0.0,
00151                   plepton*sqrt(1.0-costl*costl),plepton*costl);
00152         p4nu.set(plepton,0.0,
00153                  -1.0*plepton*sqrt(1.0-costl*costl),-1.0*plepton*costl);
00154 
00155         EvtVector4R boost((m-erho),0.0,0.0,1.0*prho);
00156         p4lepton=boostTo(p4lepton,boost);
00157         p4nu=boostTo(p4nu,boost);
00158 
00159         //Now initialize the daughters...
00160 
00161         daughter->init(meson,p4meson);
00162         lep->init(lepton,p4lepton);
00163         trino->init(nudaug,p4nu);
00164 
00165         CalcAmp(root_part,amp,FormFactors);
00166 
00167         //Now find the probability at this q2 and cos theta lepton point
00168         //and compare to maxfoundprob.
00169 
00170         //Do a little magic to get the probability!!
00171         prob = rho.NormalizedProb(amp.getSpinDensity());
00172 
00173         probctl[j]=prob;
00174       }
00175 
00176       //probclt contains prob at ctl=-1,0,1.
00177       //prob=a+b*ctl+c*ctl^2
00178 
00179       double a=probctl[1];
00180       double b=0.5*(probctl[2]-probctl[0]);
00181       double c=0.5*(probctl[2]+probctl[0])-probctl[1];
00182 
00183       prob=probctl[0];
00184       if (probctl[1]>prob) prob=probctl[1];
00185       if (probctl[2]>prob) prob=probctl[2];
00186 
00187       if (fabs(c)>1e-20){
00188         double ctlx=-0.5*b/c;
00189         if (fabs(ctlx)<1.0){
00190           double probtmp=a+b*ctlx+c*ctlx*ctlx;
00191           if (probtmp>prob) prob=probtmp;
00192         } 
00193 
00194       }
00195 
00196       //report(DEBUG,"EvtGen") << "prob,probctl:"<<prob<<" "
00197       //                            << probctl[0]<<" "
00198       //                            << probctl[1]<<" "
00199       //                            << probctl[2]<<endl;
00200 
00201       if ( prob > maxfoundprob ) {
00202         maxfoundprob = prob; 
00203       }
00204 
00205     }
00206     if ( EvtPDL::getWidth(meson) <= 0.0 ) {
00207       //if the particle is narrow dont bother with changing the mass.
00208       massiter = 4;
00209     }
00210 
00211   }
00212   root_part->deleteTree();  
00213 
00214   maxfoundprob *=1.1;
00215   return maxfoundprob;
00216   
00217 }


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