new classes for track segments
[u/mrichter/AliRoot.git] / EMCAL / AliEMCALFast.cxx
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f3c4a6df 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
155f1576 16
17/*
18$Log$
b03ac336 19Revision 1.3 2002/02/05 11:32:15 morsch
20Smearing parameters with TRD included added.
21
33e0ecee 22Revision 1.2 2002/01/18 03:27:12 morsch
23Acceptance and random rejection added.
24
155f1576 25*/
26
f3c4a6df 27
28//*-- Author: Andreas Morsch (CERN)
29
30#include "AliEMCALFast.h"
31#include <TRandom.h>
32
33
34ClassImp(AliEMCALFast)
35
36//____________________________________________________________________________
37
38
39Float_t AliEMCALFast::SmearMomentum(Int_t ind, Float_t p)
40{
41//
155f1576 42// The relative momentum error, i.e.
43// (delta p)/p = sqrt (a**2 + (b*p)**2) * 10**-2,
f3c4a6df 44// where typically a = 0.75 and b = 0.16 - 0.24 depending on multiplicity
45// (the lower value is for dn/d(eta) about 2000, and the higher one for 8000)
46//
33e0ecee 47// If we include information from TRD b will be by a factor 2/3 smaller.
48//
49// ind = 1: high multiplicity
50// ind = 2: low multiplicity
51// ind = 3: high multiplicity + TRD
52// ind = 4: low multiplicity + TRD
53
f3c4a6df 54 Float_t pSmeared;
55 Float_t a = 0.75;
56 Float_t b = 0.24;
33e0ecee 57
58 if (ind == 1) b = 0.24;
f3c4a6df 59 if (ind == 2) b = 0.16;
33e0ecee 60 if (ind == 3) b = 0.16;
61 if (ind == 4) b = 0.11;
f3c4a6df 62
63 Float_t sigma = p*TMath::Sqrt(a*a+b*b*p*p)*0.01;
64 pSmeared = p + gRandom->Gaus(0., sigma);
65 return pSmeared;
66}
67
68
69Float_t AliEMCALFast::Efficiency(Int_t ind, Float_t p)
70{
71// Tracking efficiency:
155f1576 72// above pt 0.5 GeV practically constant, between 90 and 95 % (again,
f3c4a6df 73// depending on multplicity)
74// below 0.5 GeV goes down to about 70% at 0.2 GeV.
75// On top of that there is 90% geometrical acceptance for tracking due
76// to TPC (dead zones between readout chambers).
f3c4a6df 77// Tracking
b03ac336 78//
79 Float_t eff = 0.9;
80 if (ind == 2) eff = 0.95;
81 if (p < 0.5) eff -= (0.5-p)*0.2/0.3;
82// Geometry
155f1576 83 eff *= 0.9;
f3c4a6df 84// Acceptance
85 return eff;
86}
87
155f1576 88Bool_t AliEMCALFast::EmcalAcceptance(Float_t eta, Float_t phi)
89{
90//
91// EMCAL eta-phi acceptance
92 Bool_t acc = kFALSE;
93 if (TMath::Abs(eta) < 0.7 &&
94 phi > 0. &&
95 phi < 120.*TMath::Pi()/180.)
96 acc = kTRUE;
97 return acc;
98}
99
100
101Bool_t AliEMCALFast::RandomReject(Float_t eff)
102{
103//
104// Random rejection
105 Bool_t rej = kFALSE;
106 Float_t ran = gRandom->Rndm();
107 if (ran > eff) rej = kTRUE;
108 return rej;
109}
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