BOSS 7.0.9
BESIII Offline Software System
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bak-BesEvtGen-00-04-08/src/EvtGen/EvtGenModels/EvtEtaDalitz.cc
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1//--------------------------------------------------------------------------
2//
3// Environment:
4// This software is part of the EvtGen package developed jointly
5// for the BaBar and CLEO collaborations. If you use all or part
6// of it, please give an appropriate acknowledgement.
7//
8// Copyright Information: See EvtGen/COPYRIGHT
9// Copyright (C) 1998 Caltech, UCSB
10//
11// Module: EvtEtaDalitz.cc
12//
13// Description: Routine to decay eta -> pi+ pi- pi0
14//
15// Modification history:
16//
17// DJL/RYD July 23, 1997 Module created
18//
19//------------------------------------------------------------------------
20//
21#include "EvtGenBase/EvtPatches.hh"
22#include <stdlib.h>
23#include "EvtGenBase/EvtParticle.hh"
24#include "EvtGenBase/EvtGenKine.hh"
25#include "EvtGenBase/EvtPDL.hh"
26#include "EvtGenModels/EvtEtaDalitz.hh"
27#include "EvtGenBase/EvtReport.hh"
28#include <string>
29
31
32void EvtEtaDalitz::getName(std::string& model_name){
33
34 model_name="ETA_DALITZ";
35
36}
37
38
40
41 return new EvtEtaDalitz;
42
43}
44
46
47 // check that there are 0 arguments
48 checkNArg(0);
49 checkNDaug(3);
50
52
56}
57
58
60
61 setProbMax(2.1);
62
63}
64
66
68
69 EvtVector4R mompi0 = p->getDaug(2)->getP4();
70 double masspip = p->getDaug(0)->mass();
71 double masspim = p->getDaug(1)->mass();
72 double masspi0 = p->getDaug(2)->mass();
73 double m_eta = p->mass();
74
75 double y;
76
77 //The decay amplitude coems from Layter et al PRD 7 pA2M5.
78 //this reference doesn't make sence!!!
79
80 y=(mompi0.get(0)-masspi0)*(3.0/(m_eta-masspip-masspim-masspi0))-1.0;
81
82 EvtComplex amp(sqrt(1.0-1.07*y),0.0);
83
84 vertex(amp);
85
86 return ;
87
88}
89
90
*********DOUBLE PRECISION m_pi INTEGER m_lenwt !max no of aux weights INTEGER m_phmax !maximum photon multiplicity ISR FSR *DOUBLE COMPLEX m_Pauli4 DOUBLE COMPLEX m_AmpBorn DOUBLE COMPLEX m_AmpBoxy DOUBLE COMPLEX m_AmpBorn1 DOUBLE COMPLEX m_AmpBorn2 DOUBLE COMPLEX m_AmpExpo2p DOUBLE COMPLEX m_Rmat DOUBLE COMPLEX m_BoxGZut !DOUBLE COMPLEX m_F1finPair2 !DOUBLE PRECISION m_Vcut DOUBLE PRECISION m_Alfinv DOUBLE PRECISION m_Lorin1 DOUBLE PRECISION m_Lorin2 DOUBLE PRECISION m_eta
Definition: GPS.h:30
void checkSpinDaughter(int d1, EvtSpinType::spintype sp)
void checkNArg(int a1, int a2=-1, int a3=-1, int a4=-1)
double initializePhaseSpace(int numdaughter, EvtId *daughters, double poleSize=-1., int whichTwo1=0, int whichTwo2=1)
double y[1000]