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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 | ||
16 | /* $Id$ */ | |
17 | ||
18 | //*-- Author: Andreas Morsch (CERN) | |
19 | ||
20 | #include "AliEMCALFast.h" | |
21 | #include <TRandom.h> | |
22 | ||
23 | ||
24 | ClassImp(AliEMCALFast) | |
25 | ||
26 | //____________________________________________________________________________ | |
27 | ||
28 | ||
29 | Float_t AliEMCALFast::SmearMomentum(Int_t ind, Float_t p) | |
30 | { | |
31 | // | |
32 | // The relative momentum error, i.e. (delta p)/p = sqrt (a**2 + (b*p)**2) * | |
33 | // 10**-2, | |
34 | // where typically a = 0.75 and b = 0.16 - 0.24 depending on multiplicity | |
35 | // (the lower value is for dn/d(eta) about 2000, and the higher one for 8000) | |
36 | // | |
37 | Float_t pSmeared; | |
38 | Float_t a = 0.75; | |
39 | Float_t b = 0.24; | |
40 | if (ind == 2) b = 0.16; | |
41 | ||
42 | Float_t sigma = p*TMath::Sqrt(a*a+b*b*p*p)*0.01; | |
43 | pSmeared = p + gRandom->Gaus(0., sigma); | |
44 | return pSmeared; | |
45 | } | |
46 | ||
47 | ||
48 | Float_t AliEMCALFast::Efficiency(Int_t ind, Float_t p) | |
49 | { | |
50 | // Tracking efficiency: | |
51 | // above pt 0.5 GeV practically constant, between 90 and 95 % (agian, | |
52 | // depending on multplicity) | |
53 | // below 0.5 GeV goes down to about 70% at 0.2 GeV. | |
54 | // On top of that there is 90% geometrical acceptance for tracking due | |
55 | // to TPC (dead zones between readout chambers). | |
56 | Float_t eff = 0.; | |
57 | // Tracking | |
58 | if (p > 0.5) { | |
59 | eff = 0.9; | |
60 | if (ind == 2) eff = 0.95; | |
61 | } else { | |
62 | eff = eff-(0.5-p)*0.2/0.3; | |
63 | } | |
64 | eff*= 0.9; | |
65 | // Acceptance | |
66 | return eff; | |
67 | } | |
68 | ||
69 | ||
70 | ||
71 | ||
72 | ||
73 | ||
74 | ||
75 |