Coding Convention Violations
[u/mrichter/AliRoot.git] / STEER / AliESDv0.cxx
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e23730c7 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
15
4f679a16 16/* $Id$ */
17
e23730c7 18//-------------------------------------------------------------------------
19// Implementation of the ESD V0 vertex class
4f679a16 20// This class is part of the Event Data Summary
21// set of classes and contains information about
22// V0 kind vertexes generated by a neutral particle
e23730c7 23// Origin: Iouri Belikov, IReS, Strasbourg, Jouri.Belikov@cern.ch
24//-------------------------------------------------------------------------
4f679a16 25
e23730c7 26#include <Riostream.h>
27#include <TMath.h>
28#include <TPDGCode.h>
29
30#include "AliESDv0.h"
31
32ClassImp(AliESDv0)
33
34AliESDv0::AliESDv0() : TObject() {
35 //--------------------------------------------------------------------
36 // Default constructor (K0s)
37 //--------------------------------------------------------------------
38 fPdgCode=kK0Short;
39 fEffMass=0.497672;
40 fChi2=1.e+33;
41 fPos[0]=fPos[1]=fPos[2]=0.;
42 fPosCov[0]=fPosCov[1]=fPosCov[2]=fPosCov[3]=fPosCov[4]=fPosCov[5]=0.;
43}
44
45Double_t AliESDv0::ChangeMassHypothesis(Int_t code) {
46 //--------------------------------------------------------------------
47 // This function changes the mass hypothesis for this V0
48 // and returns the "kinematical quality" of this hypothesis
49 //--------------------------------------------------------------------
50 Double_t nmass=0.13957, pmass=0.13957, mass=0.49767, ps=0.206;
51
52 fPdgCode=code;
53
54 switch (code) {
55 case kLambda0:
56 nmass=0.13957; pmass=0.93827; mass=1.1157; ps=0.101; break;
57 case kLambda0Bar:
58 pmass=0.13957; nmass=0.93827; mass=1.1157; ps=0.101; break;
59 case kK0Short:
60 break;
61 default:
62 cerr<<"AliV0vertex::ChangeMassHypothesis: ";
63 cerr<<"invalide PDG code ! Assuming K0s...\n";
64 fPdgCode=kK0Short;
65 break;
66 }
67
68 Double_t pxn=fNmom[0], pyn=fNmom[1], pzn=fNmom[2];
69 Double_t pxp=fPmom[0], pyp=fPmom[1], pzp=fPmom[2];
70
71 Double_t en=TMath::Sqrt(nmass*nmass + pxn*pxn + pyn*pyn + pzn*pzn);
72 Double_t ep=TMath::Sqrt(pmass*pmass + pxp*pxp + pyp*pyp + pzp*pzp);
73 Double_t pxl=pxn+pxp, pyl=pyn+pyp, pzl=pzn+pzp;
74 Double_t pl=TMath::Sqrt(pxl*pxl + pyl*pyl + pzl*pzl);
75
76 fEffMass=TMath::Sqrt((en+ep)*(en+ep)-pl*pl);
77
78 Double_t beta=pl/(en+ep);
79 Double_t pln=(pxn*pxl + pyn*pyl + pzn*pzl)/pl;
80 Double_t plp=(pxp*pxl + pyp*pyl + pzp*pzl)/pl;
81
82 Double_t pt2=pxp*pxp + pyp*pyp + pzp*pzp - plp*plp;
83
84 Double_t a=(plp-pln)/(plp+pln);
85 a -= (pmass*pmass-nmass*nmass)/(mass*mass);
86 a = 0.25*beta*beta*mass*mass*a*a + pt2;
87
88 return (a - ps*ps);
89
90}
91
92void AliESDv0::GetPxPyPz(Double_t &px, Double_t &py, Double_t &pz) const {
93 //--------------------------------------------------------------------
94 // This function returns V0's momentum (global)
95 //--------------------------------------------------------------------
96 px=fNmom[0]+fPmom[0];
97 py=fNmom[1]+fPmom[1];
98 pz=fNmom[2]+fPmom[2];
99}
100
101void AliESDv0::GetXYZ(Double_t &x, Double_t &y, Double_t &z) const {
102 //--------------------------------------------------------------------
103 // This function returns V0's position (global)
104 //--------------------------------------------------------------------
105 x=fPos[0];
106 y=fPos[1];
107 z=fPos[2];
108}
109
110Double_t AliESDv0::GetD(Double_t x0, Double_t y0, Double_t z0) const {
111 //--------------------------------------------------------------------
112 // This function returns V0's impact parameter
113 //--------------------------------------------------------------------
114 Double_t x=fPos[0],y=fPos[1],z=fPos[2];
115 Double_t px=fNmom[0]+fPmom[0];
116 Double_t py=fNmom[1]+fPmom[1];
117 Double_t pz=fNmom[2]+fPmom[2];
118
119 Double_t dx=(y0-y)*pz - (z0-z)*py;
120 Double_t dy=(x0-x)*pz - (z0-z)*px;
121 Double_t dz=(x0-x)*py - (y0-y)*px;
122 Double_t d=TMath::Sqrt((dx*dx+dy*dy+dz*dz)/(px*px+py*py+pz*pz));
123 return d;
124}