]>
Commit | Line | Data |
---|---|---|
da0e9ce3 | 1 | //----------------------------------------------------------------------- |
2 | // File and Version Information: | |
3 | // $Id: EvtPto3P.cc,v 1.13 2004/12/21 22:16:05 ryd 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/EvtPatches.hh" | |
19 | #include "EvtGenBase/EvtPDL.hh" | |
20 | #include "EvtGenModels/EvtPto3P.hh" | |
21 | #include "EvtGenBase/EvtPto3PAmpFactory.hh" | |
22 | using namespace EvtCyclic3; | |
23 | ||
24 | EvtDalitzPlot EvtPto3P::dp() | |
25 | { | |
26 | // There must be 3 daughters. All particles must be pseudoscalars. | |
27 | // Charge must be conserved. Number of arguments must be non-zero. | |
28 | ||
29 | EvtId parent = getParentId(); | |
30 | assert(getNDaug() == 3); | |
31 | EvtId dau0 = getDaug(0); | |
32 | EvtId dau1 = getDaug(1); | |
33 | EvtId dau2 = getDaug(2); | |
34 | ||
35 | assert(EvtPDL::getSpinType(parent) == EvtSpinType::SCALAR); | |
36 | assert(EvtPDL::getSpinType(dau0) == EvtSpinType::SCALAR); | |
37 | assert(EvtPDL::getSpinType(dau1) == EvtSpinType::SCALAR); | |
38 | assert(EvtPDL::getSpinType(dau2) == EvtSpinType::SCALAR); | |
39 | assert(EvtPDL::chg3(parent) == EvtPDL::chg3(dau0) + EvtPDL::chg3(dau1) + EvtPDL::chg3(dau2)); | |
40 | assert(getNArg() > 0); | |
41 | ||
42 | return EvtDalitzPlot(EvtPDL::getMass(dau0),EvtPDL::getMass(dau1),EvtPDL::getMass(dau2),EvtPDL::getMass(parent)); | |
43 | } | |
44 | ||
45 | EvtAmpFactory<EvtDalitzPoint>* EvtPto3P::createFactory(const EvtMultiChannelParser& parser) | |
46 | { | |
47 | // Compute the interval size | |
48 | ||
49 | EvtDalitzPlot plot = dp(); | |
50 | EvtAmpFactory<EvtDalitzPoint>* fact = new EvtPto3PAmpFactory(plot); | |
51 | fact->build(parser,10000); | |
52 | return fact; | |
53 | } | |
54 | ||
55 | ||
56 | std::vector<EvtVector4R> EvtPto3P::initDaughters(const EvtDalitzPoint& x) const | |
57 | { | |
58 | std::vector<EvtVector4R> v; | |
59 | assert(x.isValid()); | |
60 | ||
61 | // Calculate in the r.f. of AB | |
62 | ||
63 | double eA = x.e(A,AB); | |
64 | double eB = x.e(B,AB); | |
65 | double eC = x.e(C,AB); | |
66 | double pA = x.p(A,AB); | |
67 | double pC = x.p(C,AB); | |
68 | double cos = x.cosTh(CA,AB); | |
69 | double sin = sqrt(1.0-cos*cos); | |
70 | ||
71 | EvtVector4R vA(eA,0,0,pA); | |
72 | EvtVector4R vB(eB,0,0,-pA); | |
73 | EvtVector4R vC(eC,0,pC*sin,pC*cos); | |
74 | ||
75 | // Boost from rest frame of AB to rest-frame of decaying particle | |
76 | // vboost is the 4-momentum of frame being boosted from in the frame | |
77 | // being boosted into. | |
78 | ||
79 | EvtVector4R vboost = vA + vB + vC; | |
80 | vboost.set(1,-vboost.get(1)); | |
81 | vboost.set(2,-vboost.get(2)); | |
82 | vboost.set(3,-vboost.get(3)); | |
83 | vA.applyBoostTo(vboost); | |
84 | vB.applyBoostTo(vboost); | |
85 | vC.applyBoostTo(vboost); | |
86 | ||
87 | // Rotate | |
88 | ||
89 | double alpha = EvtRandom::Flat( EvtConst::twoPi ); | |
90 | double beta = acos(EvtRandom::Flat( -1.0, 1.0 )); | |
91 | double gamma = EvtRandom::Flat( EvtConst::twoPi ); | |
92 | ||
93 | vA.applyRotateEuler( alpha, beta, gamma ); | |
94 | vB.applyRotateEuler( alpha, beta, gamma ); | |
95 | vC.applyRotateEuler( alpha, beta, gamma ); | |
96 | ||
97 | // Fill vector | |
98 | ||
99 | assert(v.size() == 0); | |
100 | v.push_back(vA); | |
101 | v.push_back(vB); | |
102 | v.push_back(vC); | |
103 | ||
104 | return v; | |
105 | } | |
106 | ||
107 | ||
108 | ||
109 | ||
110 | ||
111 | ||
112 | ||
113 | ||
114 | ||
115 | ||
116 |