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da0e9ce3 | 1 | //----------------------------------------------------------------------- |
2 | // File and Version Information: | |
3 | // $Id: EvtMassAmp.cc,v 1.11 2006/01/25 19:55:43 lange Exp $ | |
4 | // | |
5 | // Environment: | |
6 | // This software is part of the EvtGen package developed jointly | |
7 | // for the BaBar and CLEO collaborations. If you use all or part | |
8 | // of it, please give an appropriate acknowledgement. | |
9 | // | |
10 | // Copyright Information: | |
11 | // Copyright (C) 1998 Caltech, UCSB | |
12 | // | |
13 | // Module creator: | |
14 | // Alexei Dvoretskii, Caltech, 2001-2002. | |
15 | //----------------------------------------------------------------------- | |
16 | #include "EvtGenBase/EvtPatches.hh" | |
17 | ||
18 | #include "EvtGenBase/EvtMassAmp.hh" | |
19 | ||
20 | EvtMassAmp::EvtMassAmp(const EvtPropBreitWignerRel& prop, const EvtTwoBodyVertex& vd) | |
21 | : EvtAmplitude<EvtPoint1D>() | |
22 | ,_prop(prop), _vd(vd), _vb(0) | |
23 | ,_useBirthFact(false), _useDeathFact(false) | |
24 | ,_useBirthFactFF(false), _useDeathFactFF(false) | |
25 | {} | |
26 | ||
27 | EvtMassAmp::EvtMassAmp(const EvtMassAmp& other) | |
28 | : EvtAmplitude<EvtPoint1D>(other) | |
29 | ,_prop(other._prop), _vd(other._vd) | |
30 | ,_vb(other._vb ? new EvtTwoBodyVertex(*other._vb) : 0) | |
31 | ,_useBirthFact(other._useBirthFact) | |
32 | ,_useDeathFact(other._useDeathFact) | |
33 | ,_useBirthFactFF(other._useBirthFactFF) | |
34 | ,_useDeathFactFF(other._useDeathFactFF) | |
35 | {} | |
36 | ||
37 | ||
38 | EvtMassAmp::~EvtMassAmp() | |
39 | { | |
40 | if(_vb) delete _vb; | |
41 | } | |
42 | ||
43 | ||
44 | EvtComplex EvtMassAmp::amplitude(const EvtPoint1D& p) const | |
45 | { | |
46 | // Modified vertex | |
47 | ||
48 | double m = p.value(); | |
49 | // keep things from crashing.. | |
50 | ||
51 | if ( m< (_vd.mA()+_vd.mB()) ) return EvtComplex(0.,0.); | |
52 | ||
53 | EvtTwoBodyKine vd(_vd.mA(),_vd.mB(),m); | |
54 | ||
55 | // Compute mass-dependent width for relativistic propagator | |
56 | ||
57 | EvtPropBreitWignerRel bw(_prop.m0(),_prop.g0()*_vd.widthFactor(vd)); | |
58 | EvtComplex amp = bw.evaluate(m); | |
59 | ||
60 | ||
61 | // Birth vertex factors | |
62 | ||
63 | if(_useBirthFact) { | |
64 | ||
65 | assert(_vb); | |
66 | if ( (m+_vb->mB()) < _vb->mAB() ) { | |
67 | EvtTwoBodyKine vb(m,_vb->mB(),_vb->mAB()); | |
68 | amp *= _vb->phaseSpaceFactor(vb,EvtTwoBodyKine::AB); | |
69 | amp *= sqrt((vb.p() / _vb->pD())); | |
70 | ||
71 | if(_useBirthFactFF) { | |
72 | ||
73 | assert(_vb); | |
74 | amp *= _vb->formFactor(vb); | |
75 | } | |
76 | } | |
77 | else{ | |
78 | if ( _vb->L() != 0 ) amp=0.; | |
79 | } | |
80 | } | |
81 | ||
82 | ||
83 | // Decay vertex factors | |
84 | ||
85 | if(_useDeathFact) { | |
86 | amp *= _vd.phaseSpaceFactor(vd,EvtTwoBodyKine::AB); | |
87 | amp *= sqrt((vd.p() / _vd.pD())); | |
88 | } | |
89 | if(_useDeathFactFF) amp *= _vd.formFactor(vd); | |
90 | ||
91 | return amp; | |
92 | } | |
93 | ||
94 | ||
95 | ||
96 | ||
97 | ||
98 |