#include "PHOTONS++/MEs/Z_To_Fermion_Fermion.H" #include "ATOOLS/Math/Poincare.H" #include "ATOOLS/Phys/Flavour.H" #include "ATOOLS/Phys/Particle.H" #include "METOOLS/Main/XYZFuncs.H" #include "METOOLS/Main/Polarization_Tools.H" using namespace PHOTONS; using namespace ATOOLS; using namespace METOOLS; using namespace std; Z_To_Fermion_Fermion::Z_To_Fermion_Fermion (const Particle_Vector_Vector& pvv) : PHOTONS_ME_Base(pvv), Dipole_FF(pvv) { m_name = "Z_To_Fermion_Fermion"; m_flavs[0] = pvv[1][0]->Flav(); m_masses[0] = pvv[1][0]->FinalMass(); // switch ordering if necessary m_switch = pvv[2][0]->Flav().IsAnti(); // m_switch == true if first multipole particle is anti if (m_switch == false) { m_flavs[1] = pvv[2][0]->Flav(); m_masses[1] = pvv[2][0]->FinalMass(); m_flavs[2] = pvv[2][1]->Flav(); m_masses[2] = pvv[2][1]->FinalMass(); } else { m_flavs[2] = pvv[2][0]->Flav(); m_masses[2] = pvv[2][0]->FinalMass(); m_flavs[1] = pvv[2][1]->Flav(); m_masses[1] = pvv[2][1]->FinalMass(); } for (unsigned int i=3; i<9; i++) { m_flavs[i] = Flavour(kf_photon); m_masses[i] = 0.; } // v = I3 - 2Q sW2 ; a = I3 // cL = v+a = 2I3 - 2Q sW2 // cR = v-a = - 2Q sW2 // also include global pre-factor ie/2sWcW // always use the particle, not the anti-particle -> position 1 m_cL = -m_i*m_e/(2.*m_sW*m_cW)*(2.*m_flavs[1].IsoWeak() -2.*m_flavs[1].Charge()*m_sW*m_sW); m_cR = -m_i*m_e/(2.*m_sW*m_cW)*(-2.*m_flavs[1].Charge()*m_sW*m_sW); } Z_To_Fermion_Fermion::~Z_To_Fermion_Fermion() { } void Z_To_Fermion_Fermion::BoostOriginalPVVToMultipoleCMS() { // m_pvv_one already in multipole CMS // m_pvv_zero in arbitrary frame -> boost m_olddipole into its CMS // and rotate m_olddipole.at(0) into +z direction Vec4D sum(0.,0.,0.,0.); for (unsigned int i=0; iMomentum(); } Vec4D p1 = m_olddipole[0]->Momentum(); p_boost = new Poincare(sum); p_boost->Boost(p1); p_rot = new Poincare(p1,Vec4D(0.,0.,0.,1.)); for (unsigned int i=0; iMomentum(); p_boost->Boost(vec); p_rot->Rotate(vec); m_olddipole[i]->SetMomentum(vec); } for (unsigned int i=0; iMomentum(); p_boost->Boost(vec); p_rot->Rotate(vec); m_oldspectator[i]->SetMomentum(vec); } } void Z_To_Fermion_Fermion::FillMomentumArrays (const Particle_Vector_Vector& pvv_one) { // m_moms0 - no photon m_moms0[0] = m_pvv_zero[1][0]->Momentum(); if (m_switch == false) { m_moms0[1] = m_pvv_zero[2][0]->Momentum(); m_moms0[2] = m_pvv_zero[2][1]->Momentum(); } else { m_moms0[2] = m_pvv_zero[2][0]->Momentum(); m_moms0[1] = m_pvv_zero[2][1]->Momentum(); } // m_moms1 - project multiphoton state onto one photon phase space // do reconstruction procedure again pretending only one photon was generated // not necessary if only one photon if (pvv_one[4].size() == 1) { m_moms1[0][0] = pvv_one[1][0]->Momentum(); if (m_switch == false) { m_moms1[0][1] = pvv_one[2][0]->Momentum(); m_moms1[0][2] = pvv_one[2][1]->Momentum(); } else { m_moms1[0][2] = pvv_one[2][0]->Momentum(); m_moms1[0][1] = pvv_one[2][1]->Momentum(); } m_moms1[0][3] = pvv_one[4][0]->Momentum(); } else { Dipole_FF::DefineDipole(); BoostOriginalPVVToMultipoleCMS(); for (unsigned int i=0; iMomentum(); m_moms1[i][2] = m_newdipole[1]->Momentum(); } else { m_moms1[i][2] = m_newdipole[0]->Momentum(); m_moms1[i][1] = m_newdipole[1]->Momentum(); } m_moms1[i][3] = m_softphotons[0]->Momentum(); m_moms1[i][0] = m_moms1[i][1]+m_moms1[i][2]+m_moms1[i][3]; m_softphotons.clear(); } } } double Z_To_Fermion_Fermion::Smod(unsigned int kk) { m_moms = m_moms1[kk]; Vec4D k = m_moms[3]; Vec4D pi = m_moms[1]; Vec4D pj = m_moms[2]; double Zi = m_flavs[1].Charge(); double Zj = m_flavs[2].Charge(); int ti = +1; int tj = +1; return m_alpha/(4.*M_PI*M_PI)*Zi*Zj*ti*tj*(pi/(pi*k)-pj/(pj*k)).Abs2(); } Complex Z_To_Fermion_Fermion::InfraredSubtractedME_0_0() { m_moms = m_moms0; Vec4C epsZ = Polarization_Vector(m_moms[0])[m_spins[0]]; XYZFunc XYZ(3,m_moms,m_flavs,false); return XYZ.X(1,m_spins[1],epsZ,2,m_spins[2],m_cR,m_cL); } Complex Z_To_Fermion_Fermion::InfraredSubtractedME_0_1() { return 0.; } Complex Z_To_Fermion_Fermion::InfraredSubtractedME_0_2() { return 0.; } Complex Z_To_Fermion_Fermion::InfraredSubtractedME_1_05(unsigned int i) { m_moms = m_moms1[i]; // set to set of momenta to be used Vec4C epsZ = Polarization_Vector(m_moms[0])[m_spins[0]]; Vec4C epsP = conj(Polarization_Vector(m_moms[3])[m_spins[3]]); Vec4D pa = m_moms[1]+m_moms[3]; // fermion propagator momenta Vec4D pb = m_moms[2]+m_moms[3]; double m = 0.5*(m_masses[1]+m_masses[2]); // fermion mass/propagator pole m_moms[4] = m_moms[5] = pa; // enter those into m_moms m_moms[6] = m_moms[7] = pb; m_flavs[4] = m_flavs[6] = m_flavs[1]; // set to corresponding particle/antiparticle m_flavs[5] = m_flavs[7] = m_flavs[2]; XYZFunc XYZ(8,m_moms,m_flavs,false); Complex r1 = Complex(0.,0.); Complex r2 = Complex(0.,0.); Complex r3 = Complex(0.,0.); Complex r4 = Complex(0.,0.); // emission off fermion (a) and (b) for (unsigned int s=0; s<=1; s++) { r1 += XYZ.X(1,m_spins[1],epsP,4,s,1.,1.) *XYZ.X(4,s,epsZ,2,m_spins[2],m_cR,m_cL); r2 += XYZ.X(1,m_spins[1],epsP,5,s,1.,1.) *XYZ.X(5,s,epsZ,2,m_spins[2],m_cR,m_cL); r3 += XYZ.X(1,m_spins[1],epsZ,6,s,m_cR,m_cL) *XYZ.X(6,s,epsP,2,m_spins[2],1.,1.); r4 += XYZ.X(1,m_spins[1],epsZ,7,s,m_cR,m_cL) *XYZ.X(7,s,epsP,2,m_spins[2],1.,1.); } // add prefactors r1 *= m_e/(2.*(pa*pa-m*m))*(1.+m/sqrt(pa*pa)); r2 *= m_e/(2.*(pa*pa-m*m))*(1.-m/sqrt(pa*pa)); r3 *= -m_e/(2.*(pb*pb-m*m))*(1.-m/sqrt(pb*pb)); r4 *= -m_e/(2.*(pb*pb-m*m))*(1.+m/sqrt(pb*pb)); // erase intermediate entries from m_flavs m_flavs[4] = m_flavs[5] = m_flavs[6] = m_flavs[7] = Flavour(kf_none); return (r1+r2+r3+r4); } Complex Z_To_Fermion_Fermion::InfraredSubtractedME_1_15(unsigned int i) { return 0.; } Complex Z_To_Fermion_Fermion::InfraredSubtractedME_2_1(unsigned int i, unsigned int j) { return 0.; } double Z_To_Fermion_Fermion::GetBeta_0_0() { double sum = 0.; for (unsigned int i=0; i<=1; i++) { // spin l.Bar for (unsigned int j=0; j<=1; j++) { // spin l for (unsigned int k=0; k<=2; k++) { // spin Z m_spins[0] = k; m_spins[1] = j; m_spins[2] = i; Complex M_0_0 = InfraredSubtractedME_0_0(); sum = sum + (M_0_0*conj(M_0_0)).real(); } } } // spin avarage over initial state sum = (1./3.)*sum; return sum; } double Z_To_Fermion_Fermion::GetBeta_0_1() { // in limit mZ >> ml return m_alpha/M_PI*(2.*log(m_M/(0.5*(m_masses[1]+m_masses[2])))+3./2.) *GetBeta_0_0(); } double Z_To_Fermion_Fermion::GetBeta_0_2() { // in limit mZ >> ml return 1./2.*sqr(m_alpha/M_PI*2.*log(m_M/(0.5*(m_masses[1]+m_masses[2])))) *GetBeta_0_0(); } double Z_To_Fermion_Fermion::GetBeta_1_1(unsigned int a) { double sum = 0.; for (unsigned int i=0; i<=1; i++) { // spin l.Bar for (unsigned int j=0; j<=1; j++) { // spin l for (unsigned int k=0; k<=2; k++) { // spin Z for (unsigned int l=0; l<=1; l++) { // spin gamma m_spins[0] = k; m_spins[1] = j; m_spins[2] = i; m_spins[3] = l; Complex M_1_05 = InfraredSubtractedME_1_05(a); sum = sum + (M_1_05*conj(M_1_05)).real(); } } } } // spin avarage over initial state sum = (1./3.)*sum; sum = 1./(16.*M_PI*M_PI*M_PI)*sum - Smod(a)*GetBeta_0_0(); return sum; } double Z_To_Fermion_Fermion::GetBeta_1_2(unsigned int i) { return 0.; } double Z_To_Fermion_Fermion::GetBeta_2_2(unsigned int i, unsigned int j) { return 0.; } DECLARE_PHOTONS_ME_GETTER(Z_To_Fermion_Fermion, "Z_To_Fermion_Fermion") PHOTONS_ME_Base *ATOOLS::Getter:: operator()(const Particle_Vector_Vector &pvv) const { if ( (pvv.size() == 4) && (pvv[0].size() == 0) && (pvv[1].size() == 1) && (pvv[1][0]->Flav().Kfcode() == kf_Z) && (pvv[2].size() == 2) && pvv[2][0]->Flav().IsFermion() && (pvv[2][0]->Flav() == pvv[2][1]->Flav().Bar()) && (pvv[3].size() == 0)) return new Z_To_Fermion_Fermion(pvv); return NULL; }