#include <TDatabasePDG.h>
#include <TMath.h>
#include <TVector3.h>
#include "AliESDcascade.h"
#include "AliLog.h"
ClassImp(AliESDcascade)
AliESDcascade::AliESDcascade() :
AliESDv0(),
fEffMassXi(TDatabasePDG::Instance()->GetParticle(kXiMinus)->Mass()),
fChi2Xi(1024),
fDcaXiDaughters(1024),
fPdgCodeXi(kXiMinus),
fBachIdx(-1)
{
for (Int_t j=0; j<3; j++) {
fPosXi[j]=0.;
fBachMom[j]=0.;
}
fPosCovXi[0]=1024;
fPosCovXi[1]=fPosCovXi[2]=0.;
fPosCovXi[3]=1024;
fPosCovXi[4]=0.;
fPosCovXi[5]=1024;
fBachMomCov[0]=1024;
fBachMomCov[1]=fBachMomCov[2]=0.;
fBachMomCov[3]=1024;
fBachMomCov[4]=0.;
fBachMomCov[5]=1024;
}
AliESDcascade::AliESDcascade(const AliESDcascade& cas) :
AliESDv0(cas),
fEffMassXi(cas.fEffMassXi),
fChi2Xi(cas.fChi2Xi),
fDcaXiDaughters(cas.fDcaXiDaughters),
fPdgCodeXi(cas.fPdgCodeXi),
fBachIdx(cas.fBachIdx)
{
for (int i=0; i<3; i++) {
fPosXi[i] = cas.fPosXi[i];
fBachMom[i] = cas.fBachMom[i];
}
for (int i=0; i<6; i++) {
fPosCovXi[i] = cas.fPosCovXi[i];
fBachMomCov[i] = cas.fBachMomCov[i];
}
}
AliESDcascade::AliESDcascade(const AliESDv0 &v,
const AliExternalTrackParam &t, Int_t i) :
AliESDv0(v),
fEffMassXi(TDatabasePDG::Instance()->GetParticle(kXiMinus)->Mass()),
fChi2Xi(1024),
fDcaXiDaughters(1024),
fPdgCodeXi(kXiMinus),
fBachIdx(i)
{
Double_t r[3]; t.GetXYZ(r);
Double_t x1=r[0], y1=r[1], z1=r[2];
Double_t p[3]; t.GetPxPyPz(p);
Double_t px1=p[0], py1=p[1], pz1=p[2];
Double_t x2,y2,z2;
v.GetXYZ(x2,y2,z2);
Double_t px2,py2,pz2;
v.GetPxPyPz(px2,py2,pz2);
Double_t a2=((x1-x2)*px2+(y1-y2)*py2+(z1-z2)*pz2)/(px2*px2+py2*py2+pz2*pz2);
Double_t xm=x2+a2*px2;
Double_t ym=y2+a2*py2;
Double_t zm=z2+a2*pz2;
fPosXi[0]=0.5*(x1+xm); fPosXi[1]=0.5*(y1+ym); fPosXi[2]=0.5*(z1+zm);
Double_t e1=TMath::Sqrt(0.13957*0.13957 + px1*px1 + py1*py1 + pz1*pz1);
Double_t e2=TMath::Sqrt(1.11568*1.11568 + px2*px2 + py2*py2 + pz2*pz2);
fEffMassXi=TMath::Sqrt((e1+e2)*(e1+e2)-
(px1+px2)*(px1+px2)-(py1+py2)*(py1+py2)-(pz1+pz2)*(pz1+pz2));
fBachMom[0]=px1; fBachMom[1]=py1; fBachMom[2]=pz1;
if (t.Charge()<0)
fPdgCodeXi = kXiMinus;
else
fPdgCodeXi = kXiPlusBar;
fPosCovXi[0]=1024;
fPosCovXi[1]=fPosCovXi[2]=0.;
fPosCovXi[3]=1024;
fPosCovXi[4]=0.;
fPosCovXi[5]=1024;
fBachMomCov[0]=1024;
fBachMomCov[1]=fBachMomCov[2]=0.;
fBachMomCov[3]=1024;
fBachMomCov[4]=0.;
fBachMomCov[5]=1024;
fChi2Xi=1024.;
}
AliESDcascade& AliESDcascade::operator=(const AliESDcascade& cas)
{
if(this==&cas) return *this;
AliESDv0::operator=(cas);
fEffMassXi = cas.fEffMassXi;
fChi2Xi = cas.fChi2Xi;
fDcaXiDaughters = cas.fDcaXiDaughters;
fPdgCodeXi = cas.fPdgCodeXi;
fBachIdx = cas.fBachIdx;
for (int i=0; i<3; i++) {
fPosXi[i] = cas.fPosXi[i];
fBachMom[i] = cas.fBachMom[i];
}
for (int i=0; i<6; i++) {
fPosCovXi[i] = cas.fPosCovXi[i];
fBachMomCov[i] = cas.fBachMomCov[i];
}
return *this;
}
void AliESDcascade::Copy(TObject &obj) const {
if(this==&obj)return;
AliESDcascade *robj = dynamic_cast<AliESDcascade*>(&obj);
if(!robj)return;
*robj = *this;
}
AliESDcascade::~AliESDcascade() {
}
Double_t AliESDcascade::E() const {
return E(fPdgCodeXi);
}
Double_t AliESDcascade::Y() const {
return Y(fPdgCodeXi);
}
Double_t AliESDcascade::E(Int_t pdg) const {
Double_t mass = TDatabasePDG::Instance()->GetParticle(pdg)->Mass();
return TMath::Sqrt(mass*mass+P()*P());
}
Double_t AliESDcascade::Y(Int_t pdg) const {
return 0.5*TMath::Log((E(pdg)+Pz())/(E(pdg)-Pz()+1.e-13));
}
Double_t AliESDcascade::RapXi() const {
return Y(kXiMinus);
}
Double_t AliESDcascade::RapOmega() const {
return Y(kOmegaMinus);
}
Double_t AliESDcascade::AlphaXi() const {
TVector3 momBach(fBachMom[0],fBachMom[1],fBachMom[2]);
TVector3 momV0(fNmom[0]+fPmom[0],fNmom[1]+fPmom[1],fNmom[2]+fPmom[2]);
TVector3 momTot(Px(),Py(),Pz());
Double_t lQlBach = momBach.Dot(momTot)/momTot.Mag();
Double_t lQlV0 = momV0.Dot(momTot)/momTot.Mag();
return 1.-2./(1.+lQlBach/lQlV0);
}
Double_t AliESDcascade::PtArmXi() const {
TVector3 momBach(fBachMom[0],fBachMom[1],fBachMom[2]);
TVector3 momTot(Px(),Py(),Pz());
return momBach.Perp(momTot);
}
Double_t AliESDcascade::ChangeMassHypothesis(Double_t &v0q, Int_t code) {
Double_t nmass=0.13957, pmass=0.93827, ps0=0.101;
Double_t bmass=0.13957, mass =1.3213, ps =0.139;
if (Charge()*code<0)
fPdgCodeXi = code;
else {
AliWarning("Chosen PDG code does not match the sign of the bachelor... Corrected !!");
fPdgCodeXi = -code;
}
switch (fPdgCodeXi) {
case kXiMinus:
break;
case kXiPlusBar:
nmass=0.93827; pmass=0.13957;
break;
case kOmegaMinus:
bmass=0.49368; mass=1.67245; ps=0.211;
break;
case kOmegaPlusBar:
nmass=0.93827; pmass=0.13957;
bmass=0.49368; mass=1.67245; ps=0.211;
break;
default:
AliError("Invalide PDG code ! Assuming a Xi particle...");
if (Charge()<0) {
fPdgCodeXi=kXiMinus;
}
else {
fPdgCodeXi=kXiPlusBar;
nmass=0.93827; pmass=0.13957;
}
break;
}
Double_t pxn=fNmom[0], pyn=fNmom[1], pzn=fNmom[2];
Double_t pxp=fPmom[0], pyp=fPmom[1], pzp=fPmom[2];
Double_t px0=pxn+pxp, py0=pyn+pyp, pz0=pzn+pzp;
Double_t p0=TMath::Sqrt(px0*px0 + py0*py0 + pz0*pz0);
Double_t e0=TMath::Sqrt(1.11568*1.11568 + p0*p0);
Double_t beta0=p0/e0;
Double_t pln=(pxn*px0 + pyn*py0 + pzn*pz0)/p0;
Double_t plp=(pxp*px0 + pyp*py0 + pzp*pz0)/p0;
Double_t pt2=pxp*pxp + pyp*pyp + pzp*pzp - plp*plp;
Double_t a=(plp-pln)/(plp+pln);
a -= (pmass*pmass-nmass*nmass)/(1.11568*1.11568);
a = 0.25*beta0*beta0*1.11568*1.11568*a*a + pt2;
v0q=a - ps0*ps0;
Double_t pxb=fBachMom[0], pyb=fBachMom[1], pzb=fBachMom[2];
Double_t eb=TMath::Sqrt(bmass*bmass + pxb*pxb + pyb*pyb + pzb*pzb);
Double_t pxl=px0+pxb, pyl=py0+pyb, pzl=pz0+pzb;
Double_t pl=TMath::Sqrt(pxl*pxl + pyl*pyl + pzl*pzl);
fEffMassXi=TMath::Sqrt(((e0+eb)-pl)*((e0+eb)+pl));
Double_t beta=pl/(e0+eb);
Double_t pl0=(px0*pxl + py0*pyl + pz0*pzl)/pl;
Double_t plb=(pxb*pxl + pyb*pyl + pzb*pzl)/pl;
pt2=p0*p0 - pl0*pl0;
a=(pl0-plb)/(pl0+plb);
a -= (1.11568*1.11568-bmass*bmass)/(mass*mass);
a = 0.25*beta*beta*mass*mass*a*a + pt2;
return (a - ps*ps);
}
void
AliESDcascade::GetPxPyPz(Double_t &px, Double_t &py, Double_t &pz) const {
px=fNmom[0]+fPmom[0]+fBachMom[0];
py=fNmom[1]+fPmom[1]+fBachMom[1];
pz=fNmom[2]+fPmom[2]+fBachMom[2];
}
void AliESDcascade::GetXYZcascade(Double_t &x, Double_t &y, Double_t &z) const {
x=fPosXi[0];
y=fPosXi[1];
z=fPosXi[2];
}
Double_t AliESDcascade::GetDcascade(Double_t x0, Double_t y0, Double_t z0) const {
Double_t x=fPosXi[0],y=fPosXi[1],z=fPosXi[2];
Double_t px=fNmom[0]+fPmom[0]+fBachMom[0];
Double_t py=fNmom[1]+fPmom[1]+fBachMom[1];
Double_t pz=fNmom[2]+fPmom[2]+fBachMom[2];
Double_t dx=(y0-y)*pz - (z0-z)*py;
Double_t dy=(x0-x)*pz - (z0-z)*px;
Double_t dz=(x0-x)*py - (y0-y)*px;
Double_t d=TMath::Sqrt((dx*dx+dy*dy+dz*dz)/(px*px+py*py+pz*pz));
return d;
}
Double_t AliESDcascade::GetCascadeCosineOfPointingAngle(Double_t refPointX, Double_t refPointY, Double_t refPointZ) const {
Double_t momCas[3];
GetPxPyPz(momCas[0],momCas[1],momCas[2]);
Double_t deltaPos[3];
deltaPos[0] = fPosXi[0] - refPointX;
deltaPos[1] = fPosXi[1] - refPointY;
deltaPos[2] = fPosXi[2] - refPointZ;
Double_t momCas2 = momCas[0]*momCas[0] + momCas[1]*momCas[1] + momCas[2]*momCas[2];
Double_t deltaPos2 = deltaPos[0]*deltaPos[0] + deltaPos[1]*deltaPos[1] + deltaPos[2]*deltaPos[2];
Double_t cosinePointingAngle = (deltaPos[0]*momCas[0] +
deltaPos[1]*momCas[1] +
deltaPos[2]*momCas[2] ) /
TMath::Sqrt(momCas2 * deltaPos2);
return cosinePointingAngle;
}
void AliESDcascade::GetPosCovXi(Double_t cov[6]) const {
for (Int_t i=0; i<6; ++i) cov[i] = fPosCovXi[i];
}