EvtHNLSemiLeptonicScalarAmp Class Reference

Amplitude calculator for semileptonic HNL scalar decays. More...

#include <EvtHNLSemiLeptonicScalarAmp.h>

Inheritance diagram for EvtHNLSemiLeptonicScalarAmp:

Private Member Functions
void	CalcAmp (EvtParticle *parent, EvtAmp &amp, EvtSemiLeptonicFF *FormFactors) override
	Daughters are initialized and have been added to the parent.

Detailed Description

Amplitude calculator for semileptonic HNL scalar decays.

Definition at line 17 of file EvtHNLSemiLeptonicScalarAmp.h.

Member Function Documentation

CalcAmp()

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

overrideprivate

Daughters are initialized and have been added to the parent.

No need to carry around the daughters seperately!

Definition at line 20 of file EvtHNLSemiLeptonicScalarAmp.cc.

{
  static EvtId EM = EvtPDL::getId("e-");
  static EvtId MUM = EvtPDL::getId("mu-");
  static EvtId TAUM = EvtPDL::getId("tau-");
  static EvtId EP = EvtPDL::getId("e+");
  static EvtId MUP = EvtPDL::getId("mu+");
  static EvtId TAUP = EvtPDL::getId("tau+");
 
  //Add the lepton and neutrino 4 momenta to find q2
 
  EvtVector4R q = parent->getDaug(1)->getP4() + parent->getDaug(2)->getP4();
  double q2 = (q.mass2());
 
  double fpf, f0f;
  double mesonmass = parent->getDaug(0)->mass();
  double parentmass = parent->mass();
 
  FormFactors->getscalarff(parent->getId(), parent->getDaug(0)->getId(),
                           q2, mesonmass, &fpf, &f0f);
 
  EvtVector4R p4b;
  p4b.set(parent->mass(), 0.0, 0.0, 0.0);
  EvtVector4R p4meson = parent->getDaug(0)->getP4();
  double mdiffoverq2;
  mdiffoverq2 = parentmass * parentmass - mesonmass * mesonmass;
  mdiffoverq2 = mdiffoverq2 / q2;
 
  EvtId l_num = parent->getDaug(1)->getId();
  EvtVector4C tds;
  tds = EvtVector4C(
          fpf * (p4b + p4meson - (mdiffoverq2 * (p4b - p4meson))) +
          +f0f * mdiffoverq2 * (p4b - p4meson));
 
  for (int i{0}; i < 2; ++i) {
    for (int j{0}; j < 2; ++j) {
      const EvtVector4C current{
        EvtLeptonVACurrent(parent->getDaug(2)->spParent(j),
                           parent->getDaug(1)->spParent(i))};
 
      if (l_num == EM || l_num == MUM || l_num == TAUM) {
 
        amp.vertex(i, j, current.conj() * tds);
 
      } else if (l_num == EP || l_num == MUP || l_num == TAUP) {
 
        amp.vertex(i, j, current * tds);
 
      } else {
        B2ERROR("HNLSemileptonicScalarAmp: Wrong lepton number");
      }
    }
  }
}

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The documentation for this class was generated from the following files:

• generators/evtgen/models/include/EvtHNLSemiLeptonicScalarAmp.h
• generators/evtgen/models/src/EvtHNLSemiLeptonicScalarAmp.cc