1 /**************************************************************************
2 * Copyright(c) 2004, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 //____________________________________________________________________
20 // FMD reconstructed multiplicity in a region of a ring. The region
21 // is identified by (strip_min,sector_min)x(strip_max,sector_max) or
22 // by (eta_max,phi_min),(eta_min,phi_max). It's also possible to
23 // get the peudorapidity of the center-of-mass of the region, as well
24 // as the mean azimuthal angle.
26 // [Note, that minStrip corresponds to maxEta, and maxStrip
27 // corresponds to minEta]
29 // These objects are usually created by the Poisson reconstruction
32 #include "AliFMDMultRegion.h" // ALIFMDPARTICLES_H
33 #include <TString.h> // ROOT_TString
34 #include <Riostream.h> // ROOT_Riostream
36 //____________________________________________________________________
37 ClassImp(AliFMDMultRegion)
39 ; // This is here to keep Emacs for indenting the next line
43 //____________________________________________________________________
44 AliFMDMultRegion::AliFMDMultRegion()
57 //____________________________________________________________________
58 AliFMDMultRegion::AliFMDMultRegion(UShort_t detector, Char_t ring,
59 UShort_t minSector, UShort_t maxSector,
60 UShort_t minStrip, UShort_t maxStrip,
61 Float_t minEta, Float_t maxEta,
63 Float_t minPhi, Float_t maxPhi,
64 Float_t particles, UShort_t method)
65 : AliFMDMult(particles, method),
68 fMinSector(minSector),
69 fMaxSector(maxSector),
80 //____________________________________________________________________
82 AliFMDMultRegion::Eta() const
84 // Return the center-of-mass eta of the region. This is calculated
85 // as the weighted mean of min and max eta, where the weights are
86 // the length of the arcs of the upper and lower edge of the region:
89 // f = -----------------
92 // w_max = ds*minStrip*2*pi*f
94 // w_min = ds*maxStrip*2*pi*f
96 // 1/w^2 = 1/w_max^2 + 1/w_min^2
99 // = ---------------------- + ----------------------
100 // (ds*minStrip*2*pi*f)^2 (ds*maxStrip*2*pi*f)^2
102 // (ds*maxStrip*2*pi*f)^2 + (ds*minStrip*2*pi*f)^2
103 // = -----------------------------------------------
104 // (ds*maxStrip*2*pi*f)^2 * (ds*minStrip*2*pi*f)^2
107 // 4 * pi^2 * ds^2 * f^2 (maxStrip^2 + minStrip^2)
108 // = -------------------------------------------------
109 // 16 * pi^4 * ds^4 * f^4 minStrip^2 * maxStrip^2
111 // (maxStrip^2 + minStrip^2)
112 // = -------------------------------------------------
113 // 4 * pi^2 * ds^2 * f^2 minStrip^2 * maxStrip^2
115 // <eta> = (maxEta/w_max^2 + minEta /w_min^2) / (1/w^2)
117 // w_min^2 * maxEta + w_max^2 * minEta
118 // = ------------------------------------ / (1/w^2)
121 // 4*pi^2*ds^2*(maxStrip*maxEta + minStrip*minEta)
122 // = ----------------------------------------------- / (1/w^2)
123 // 16*pi^4*ds^4*f^4*minStrip^2*maxStrip^2
125 // maxStrip * maxEta + minStrip * minEta
126 // = -------------------------------------
127 // 4*pi^2*ds^2*f^2*minStrip^2*maxStrip^2
129 // 4*pi^2*ds^2*f^2*minStrip^2*maxStrip^2
130 // * -------------------------------------
131 // maxStrip^2+minStrip^2
133 // maxStrip * maxEta + minStrip * minEta
134 // = -------------------------------------
135 // maxStrip^2 + minStrip^2
139 Float_t eta = (fMaxStrip * fMaxEta + fMinStrip * fMinEta)
140 / (fMaxStrip * fMaxStrip + fMinStrip * fMinStrip);
145 //____________________________________________________________________
147 AliFMDMultRegion::Print(Option_t* option) const
152 // D: Detector (default)
155 // E: Eta range (default)
156 // P: Phi range (default)
159 cout << "FMD Multiplicity in a region: " << fParticles << endl;
160 if (opt.Contains("D", TString::kIgnoreCase))
161 cout << " Detector: FMD" << fDetector << fRing
162 << "[" << fMinSector << "-" << fMaxSector
163 << "," << fMinStrip << "-" << fMaxStrip << "]" << endl;
164 if (opt.Contains("E", TString::kIgnoreCase))
165 cout << " Eta range: [" << fMinEta << "," << fMaxEta << endl;
166 if (opt.Contains("P", TString::kIgnoreCase))
167 cout << " Phi range: [" << fMinPhi << "," << fMaxPhi << endl;
168 AliFMDMult::Print(option);
172 //____________________________________________________________________