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da0e9ce3 | 1 | #include "EvtGenBase/EvtPatches.hh" |
2 | /******************************************************************************* | |
3 | * Project: BaBar detector at the SLAC PEP-II B-factory | |
4 | * Package: EvtGenBase | |
5 | * File: $Id: EvtTwoBodyKine.cc,v 1.8 2004/12/21 19:58:50 ryd Exp $ | |
6 | * Author: Alexei Dvoretskii, dvoretsk@slac.stanford.edu, 2001-2002 | |
7 | * | |
8 | * Copyright (C) 2002 Caltech | |
9 | *******************************************************************************/ | |
10 | ||
11 | #include <iostream> | |
12 | #include <assert.h> | |
13 | #include <math.h> | |
14 | #include "EvtGenBase/EvtTwoBodyKine.hh" | |
15 | #include "EvtGenBase/EvtReport.hh" | |
16 | using std::endl; | |
17 | using std::ostream; | |
18 | ||
19 | ||
20 | EvtTwoBodyKine::EvtTwoBodyKine() | |
21 | : _mA(0.), _mB(0.), _mAB(0.) | |
22 | {} | |
23 | ||
24 | EvtTwoBodyKine::EvtTwoBodyKine(double mA, double mB, double mAB) | |
25 | : _mA(mA), _mB(mB), _mAB(mAB) | |
26 | { | |
27 | if(mAB < mA + mB) { | |
28 | ||
29 | report(INFO,"EvtGen") << mAB << " < " << mA << " + " << mB << endl; | |
30 | assert(0); | |
31 | } | |
32 | } | |
33 | ||
34 | EvtTwoBodyKine::EvtTwoBodyKine(const EvtTwoBodyKine& other) | |
35 | : _mA(other._mA), _mB(other._mB), _mAB(other._mAB) | |
36 | {} | |
37 | ||
38 | EvtTwoBodyKine::~EvtTwoBodyKine() | |
39 | {} | |
40 | ||
41 | ||
42 | double EvtTwoBodyKine::m(Index i) const | |
43 | { | |
44 | double ret = _mAB; | |
45 | if(A == i) ret = _mA; | |
46 | else | |
47 | if(B == i) ret = _mB; | |
48 | ||
49 | return ret; | |
50 | } | |
51 | ||
52 | ||
53 | double EvtTwoBodyKine::p(Index i) const | |
54 | { | |
55 | double p0 = 0.; | |
56 | ||
57 | if(i == AB) { | |
58 | ||
59 | double x = _mAB*_mAB - _mA*_mA - _mB*_mB; | |
60 | double y = 2*_mA*_mB; | |
61 | p0 = sqrt(x*x - y*y)/2./_mAB; | |
62 | } | |
63 | else | |
64 | if(i == A) { | |
65 | ||
66 | double x = _mA*_mA - _mAB*_mAB - _mB*_mB; | |
67 | double y = 2*_mAB*_mB; | |
68 | p0 = sqrt(x*x - y*y)/2./_mA; | |
69 | } | |
70 | else { | |
71 | ||
72 | double x = _mB*_mB - _mAB*_mAB - _mA*_mA; | |
73 | double y = 2*_mAB*_mA; | |
74 | p0 = sqrt(x*x - y*y)/2./_mB; | |
75 | } | |
76 | ||
77 | return p0; | |
78 | } | |
79 | ||
80 | ||
81 | double EvtTwoBodyKine::e(Index i, Index j) const | |
82 | { | |
83 | double ret = m(i); | |
84 | if(i != j) { | |
85 | ||
86 | double pD = p(j); | |
87 | ret = sqrt(ret*ret + pD*pD); | |
88 | } | |
89 | return ret; | |
90 | } | |
91 | ||
92 | ||
93 | void EvtTwoBodyKine::print(ostream& os) const | |
94 | { | |
95 | os << " mA = " << _mA << endl; | |
96 | os << " mB = " << _mB << endl; | |
97 | os << "mAB = " << _mAB << endl; | |
98 | } | |
99 | ||
100 | ||
101 | ostream& operator<<(ostream& os, const EvtTwoBodyKine& p) | |
102 | { | |
103 | p.print(os); | |
104 | return os; | |
105 | } |