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6c94f330 1/**************************************************************************
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
16//-------------------------------------------------------------------------
17//
18// Implementation of the V0 vertex class
19// Numerical part - AliHelix functionality used
20//
21// Origin: Marian Ivanov marian.ivanov@cern.ch
22//-------------------------------------------------------------------------
23#include <TMath.h>
24
25#include "AliV0.h"
26#include "AliHelix.h"
27
28
29ClassImp(AliV0)
30
31void AliV0::Update(Float_t vertex[3])
32{
33 //
35 //
36 // Float_t distance1,distance2;
37 Float_t distance2;
38 //
39 AliHelix phelix(fParamP);
d6a49f20 40 AliHelix mhelix(fParamN);
6c94f330 41 //
42 //find intersection linear
43 //
45 Int_t points = phelix.GetRPHIintersections(mhelix, phase, radius,200);
46 Double_t delta1=10000,delta2=10000;
47 /*
48 if (points<=0) return;
49 if (points>0){
53 }
54 if (points==2){
58 }
59 distance1 = TMath::Min(delta1,delta2);
60 */
61 //
62 //find intersection parabolic
63 //
64 points = phelix.GetRPHIintersections(mhelix, phase, radius);
65 delta1=10000,delta2=10000;
66 Double_t d1=1000.,d2=10000.;
67 Double_t err[3],angles[3];
68 if (points<=0) return;
69 if (points>0){
6c94f330 73 // if we are close to vertex use error parama
74 //
d6a49f20 75 err[1] = fParamP.GetCovariance()[0]+fParamN.GetCovariance()[0]+0.05*0.05
76 +0.3*(fParamP.GetCovariance()[2]+fParamN.GetCovariance()[2]);
77 err[2] = fParamP.GetCovariance()[2]+fParamN.GetCovariance()[2]+0.05*0.05
78 +0.3*(fParamP.GetCovariance()[0]+fParamN.GetCovariance()[0]);
6c94f330 79
80 phelix.GetAngle(phase[0][0],mhelix,phase[0][1],angles);
81 Double_t tfi = TMath::Abs(TMath::Tan(angles[0]));
82 Double_t tlam = TMath::Abs(TMath::Tan(angles[1]));
83 err[0] = err[1]/((0.2+tfi)*(0.2+tfi))+err[2]/((0.2+tlam)*(0.2+tlam));
84 err[0] = ((err[1]*err[2]/((0.2+tfi)*(0.2+tfi)*(0.2+tlam)*(0.2+tlam))))/err[0];
86 }
87 Double_t xd[3],xm[3];
88 phelix.Evaluate(phase[0][0],xd);
89 mhelix.Evaluate(phase[0][1],xm);
90 d1 = (xd[0]-xm[0])*(xd[0]-xm[0])+(xd[1]-xm[1])*(xd[1]-xm[1])+(xd[2]-xm[2])*(xd[2]-xm[2]);
91 }
92 if (points==2){
6c94f330 96 // if we are close to vertex use error paramatrization
97 //
d6a49f20 98 err[1] = fParamP.GetCovariance()[0]+fParamN.GetCovariance()[0]+0.05*0.05
99 +0.3*(fParamP.GetCovariance()[2]+fParamN.GetCovariance()[2]);
100 err[2] = fParamP.GetCovariance()[2]+fParamN.GetCovariance()[2]+0.05*0.05
101 +0.3*(fParamP.GetCovariance()[0]+fParamN.GetCovariance()[0]);
6c94f330 102
103 phelix.GetAngle(phase[1][0],mhelix,phase[1][1],angles);
104 Double_t tfi = TMath::Abs(TMath::Tan(angles[0]));
105 Double_t tlam = TMath::Abs(TMath::Tan(angles[1]));
106 err[0] = err[1]/((0.2+tfi)*(0.2+tfi))+err[2]/((0.2+tlam)*(0.2+tlam));
107 err[0] = ((err[1]*err[2]/((0.2+tfi)*(0.2+tfi)*(0.2+tlam)*(0.2+tlam))))/err[0];
109 }
110 Double_t xd[3],xm[3];
111 phelix.Evaluate(phase[1][0],xd);
112 mhelix.Evaluate(phase[1][1],xm);
113 d2 = (xd[0]-xm[0])*(xd[0]-xm[0])+(xd[1]-xm[1])*(xd[1]-xm[1])+(xd[2]-xm[2])*(xd[2]-xm[2]);
114 }
115 //
116 distance2 = TMath::Min(delta1,delta2);
117 if (delta1<delta2){
118 //get V0 info
119 Double_t xd[3],xm[3];
120 phelix.Evaluate(phase[0][0],xd);
121 mhelix.Evaluate(phase[0][1], xm);
b75d63a7 122 fPos[0] = 0.5*(xd[0]+xm[0]);
123 fPos[1] = 0.5*(xd[1]+xm[1]);
124 fPos[2] = 0.5*(xd[2]+xm[2]);
6c94f330 125
d6a49f20 126 Float_t wy = fParamP.GetCovariance()[0]/(fParamP.GetCovariance()[0]+fParamN.GetCovariance()[0]);
127 Float_t wz = fParamP.GetCovariance()[2]/(fParamP.GetCovariance()[2]+fParamN.GetCovariance()[2]);
b75d63a7 128 fPos[0] = 0.5*( (1.-wy)*xd[0]+ wy*xm[0] + (1.-wz)*xd[0]+ wz*xm[0] );
129 fPos[1] = (1.-wy)*xd[1]+ wy*xm[1];
130 fPos[2] = (1.-wz)*xd[2]+ wz*xm[2];
6c94f330 131 //
b75d63a7 132 phelix.GetMomentum(phase[0][0],fPmom);
133 mhelix.GetMomentum(phase[0][1],fNmom);
6c94f330 134 phelix.GetAngle(phase[0][0],mhelix,phase[0][1],fAngle);
b75d63a7 135 fRr = TMath::Sqrt(fPos[0]*fPos[0]+fPos[1]*fPos[1]);
6c94f330 136 }
137 else{
138 Double_t xd[3],xm[3];
139 phelix.Evaluate(phase[1][0],xd);
140 mhelix.Evaluate(phase[1][1], xm);
b75d63a7 141 fPos[0] = 0.5*(xd[0]+xm[0]);
142 fPos[1] = 0.5*(xd[1]+xm[1]);
143 fPos[2] = 0.5*(xd[2]+xm[2]);
d6a49f20 144 Float_t wy = fParamP.GetCovariance()[0]/(fParamP.GetCovariance()[0]+fParamN.GetCovariance()[0]);
145 Float_t wz = fParamP.GetCovariance()[2]/(fParamP.GetCovariance()[2]+fParamN.GetCovariance()[2]);
b75d63a7 146 fPos[0] = 0.5*( (1.-wy)*xd[0]+ wy*xm[0] + (1.-wz)*xd[0]+ wz*xm[0] );
147 fPos[1] = (1.-wy)*xd[1]+ wy*xm[1];
148 fPos[2] = (1.-wz)*xd[2]+ wz*xm[2];
6c94f330 149 //
b75d63a7 150 phelix.GetMomentum(phase[1][0], fPmom);
151 mhelix.GetMomentum(phase[1][1], fNmom);
6c94f330 152 phelix.GetAngle(phase[1][0],mhelix,phase[1][1],fAngle);
b75d63a7 153 fRr = TMath::Sqrt(fPos[0]*fPos[0]+fPos[1]*fPos[1]);
6c94f330 154 }
b75d63a7 155 //Bo: fDist1 = TMath::Sqrt(TMath::Min(d1,d2));
156 //Bo: fDist2 = TMath::Sqrt(distance2);
157 fDcaV0Daughters = TMath::Sqrt(distance2);//Bo:
6c94f330 158 //
159 //
b75d63a7 160 Double_t v[3] = {fPos[0]-vertex[0],fPos[1]-vertex[1],fPos[2]-vertex[2]};
161 Double_t p[3] = {fPmom[0]+fNmom[0], fPmom[1]+fNmom[1],fPmom[2]+fNmom[2]};
6c94f330 162 Double_t vnorm2 = v[0]*v[0]+v[1]*v[1];
163 if (TMath::Abs(v[2])>100000) return;
164 Double_t vnorm3 = TMath::Sqrt(TMath::Abs(v[2]*v[2]+vnorm2));
165 vnorm2 = TMath::Sqrt(vnorm2);
166 Double_t pnorm2 = p[0]*p[0]+p[1]*p[1];
167 Double_t pnorm3 = TMath::Sqrt(p[2]*p[2]+pnorm2);
168 pnorm2 = TMath::Sqrt(pnorm2);
8de83b8e 169 if (vnorm2*pnorm2>0) {
170 fPointAngleFi = (v[0]*p[0]+v[1]*p[1])/(vnorm2*pnorm2);
171 }
172 if (vnorm3*pnorm3>0) {
173 fPointAngleTh = (v[2]*p[2]+vnorm2*pnorm2)/(vnorm3*pnorm3);
174 fPointAngle = (v[0]*p[0]+v[1]*p[1]+v[2]*p[2])/(vnorm3*pnorm3);
175 }
6c94f330 176 //
177}
178