Added customised streamer to AliMUONSt12QuadrantSegmentation (to get correct behavio...
[u/mrichter/AliRoot.git] / STEER / AliESDcascade.cxx
CommitLineData
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 cascade vertex class
4f679a16 20// This is part of the Event Summary Data
21// which contains the result of the reconstruction
22// and is the main set of classes for analaysis
e23730c7 23// Origin: Christian Kuhn, IReS, Strasbourg, christian.kuhn@ires.in2p3.fr
24//-------------------------------------------------------------------------
4f679a16 25
e23730c7 26#include <TMath.h>
27
5f7789fc 28#include "AliLog.h"
e23730c7 29#include "AliESDcascade.h"
e23730c7 30
31ClassImp(AliESDcascade)
32
33AliESDcascade::AliESDcascade() : TObject() {
34 //--------------------------------------------------------------------
35 // Default constructor (Xi-)
36 //--------------------------------------------------------------------
37 fPdgCode=kXiMinus;
38 fEffMass=1.32131;
39 fChi2=1.e+33;
40 fPos[0]=fPos[1]=fPos[2]=0.;
41 fPosCov[0]=fPosCov[1]=fPosCov[2]=fPosCov[3]=fPosCov[4]=fPosCov[5]=0.;
42}
43
44inline Double_t det(Double_t a00, Double_t a01, Double_t a10, Double_t a11){
45 // determinant 2x2
46 return a00*a11 - a01*a10;
47}
48
49inline Double_t det (Double_t a00,Double_t a01,Double_t a02,
50 Double_t a10,Double_t a11,Double_t a12,
51 Double_t a20,Double_t a21,Double_t a22) {
52 // determinant 3x3
53 return
54 a00*det(a11,a12,a21,a22)-a01*det(a10,a12,a20,a22)+a02*det(a10,a11,a20,a21);
55}
56
57Double_t AliESDcascade::ChangeMassHypothesis(Double_t &v0q, Int_t code) {
58 //--------------------------------------------------------------------
59 // This function changes the mass hypothesis for this cascade
60 // and returns the "kinematical quality" of this hypothesis
61 // together with the "quality" of associated V0 (argument v0q)
62 //--------------------------------------------------------------------
63 Double_t nmass=0.13957, pmass=0.93827, ps0=0.101;
64 Double_t bmass=0.13957, mass =1.3213, ps =0.139;
65
66 fPdgCode=code;
67
68 switch (code) {
69 case 213:
70 bmass=0.93827;
71 break;
72 case kXiMinus:
73 break;
74 case kXiPlusBar:
75 nmass=0.93827; pmass=0.13957;
76 break;
77 case kOmegaMinus:
78 bmass=0.49368; mass=1.67245; ps=0.211;
79 break;
80 case kOmegaPlusBar:
81 nmass=0.93827; pmass=0.13957;
82 bmass=0.49368; mass=1.67245; ps=0.211;
83 break;
84 default:
5f7789fc 85 AliError("Invalide PDG code ! Assuming XiMinus's...");
e23730c7 86 fPdgCode=kXiMinus;
87 break;
88 }
89
90 Double_t pxn=fV0mom[0][0], pyn=fV0mom[0][1], pzn=fV0mom[0][2];
91 Double_t pxp=fV0mom[1][0], pyp=fV0mom[1][1], pzp=fV0mom[1][2];
92 Double_t px0=pxn+pxp, py0=pyn+pyp, pz0=pzn+pzp;
93 Double_t p0=TMath::Sqrt(px0*px0 + py0*py0 + pz0*pz0);
94
95 Double_t e0=TMath::Sqrt(1.11568*1.11568 + p0*p0);
96 Double_t beta0=p0/e0;
97 Double_t pln=(pxn*px0 + pyn*py0 + pzn*pz0)/p0;
98 Double_t plp=(pxp*px0 + pyp*py0 + pzp*pz0)/p0;
99 Double_t pt2=pxp*pxp + pyp*pyp + pzp*pzp - plp*plp;
100
101 Double_t a=(plp-pln)/(plp+pln);
102 a -= (pmass*pmass-nmass*nmass)/(1.11568*1.11568);
103 a = 0.25*beta0*beta0*1.11568*1.11568*a*a + pt2;
104
105
106 v0q=a - ps0*ps0;
107
108
109 Double_t pxb=fBachMom[0], pyb=fBachMom[1], pzb=fBachMom[2];
110
111 Double_t eb=TMath::Sqrt(bmass*bmass + pxb*pxb + pyb*pyb + pzb*pzb);
112 Double_t pxl=px0+pxb, pyl=py0+pyb, pzl=pz0+pzb;
113 Double_t pl=TMath::Sqrt(pxl*pxl + pyl*pyl + pzl*pzl);
114
115 fEffMass=TMath::Sqrt((e0+eb)*(e0+eb) - pl*pl);
116
117 Double_t beta=pl/(e0+eb);
118 Double_t pl0=(px0*pxl + py0*pyl + pz0*pzl)/pl;
119 Double_t plb=(pxb*pxl + pyb*pyl + pzb*pzl)/pl;
120 pt2=p0*p0 - pl0*pl0;
121
122 a=(pl0-plb)/(pl0+plb);
123 a -= (1.11568*1.11568-bmass*bmass)/(mass*mass);
124 a = 0.25*beta*beta*mass*mass*a*a + pt2;
125
126 return (a - ps*ps);
127}
128
129void
130AliESDcascade::GetPxPyPz(Double_t &px, Double_t &py, Double_t &pz) const {
131 //--------------------------------------------------------------------
132 // This function returns the cascade momentum (global)
133 //--------------------------------------------------------------------
134 px=fV0mom[0][0]+fV0mom[1][0]+fBachMom[0];
135 py=fV0mom[0][1]+fV0mom[1][1]+fBachMom[1];
136 pz=fV0mom[0][2]+fV0mom[1][2]+fBachMom[2];
137}
138
139void AliESDcascade::GetXYZ(Double_t &x, Double_t &y, Double_t &z) const {
140 //--------------------------------------------------------------------
141 // This function returns cascade position (global)
142 //--------------------------------------------------------------------
143 x=fPos[0];
144 y=fPos[1];
145 z=fPos[2];
146}
147
148Double_t AliESDcascade::GetD(Double_t x0, Double_t y0, Double_t z0) const {
149 //--------------------------------------------------------------------
150 // This function returns the cascade impact parameter
151 //--------------------------------------------------------------------
152
153 Double_t x=fPos[0],y=fPos[1],z=fPos[2];
154 Double_t px=fV0mom[0][0]+fV0mom[1][0]+fBachMom[0];
155 Double_t py=fV0mom[0][1]+fV0mom[1][1]+fBachMom[1];
156 Double_t pz=fV0mom[0][2]+fV0mom[1][2]+fBachMom[2];
157
158 Double_t dx=(y0-y)*pz - (z0-z)*py;
159 Double_t dy=(x0-x)*pz - (z0-z)*px;
160 Double_t dz=(x0-x)*py - (y0-y)*px;
161 Double_t d=TMath::Sqrt((dx*dx+dy*dy+dz*dz)/(px*px+py*py+pz*pz));
162
163 return d;
164}
165