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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: EvtGen/EvtKine.hh | |
12 | // | |
13 | // Description:routines to calc. decay angles. | |
14 | // | |
15 | // Modification history: | |
16 | // | |
17 | // DJL/RYD September 25, 1996 Module created | |
18 | // | |
19 | //------------------------------------------------------------------------ | |
20 | ||
21 | #ifndef EVTKINE_HH | |
22 | #define EVTKINE_HH | |
23 | ||
24 | class EvtVector4R; | |
25 | class EvtComplex; | |
26 | ||
27 | double EvtDecayAngle(const EvtVector4R&, const EvtVector4R&, | |
28 | const EvtVector4R&); | |
29 | ||
30 | double EvtDecayAngleChi(const EvtVector4R&, const EvtVector4R&, | |
31 | const EvtVector4R&, const EvtVector4R&, | |
32 | const EvtVector4R& ); | |
33 | ||
34 | // | |
35 | // This routine calculates the cosine of the angle between | |
36 | // the normal of the decay plane and the flight direction of particle q | |
37 | // in the parent frame. | |
38 | // | |
39 | double EvtDecayPlaneNormalAngle(const EvtVector4R& p,const EvtVector4R& q, | |
40 | const EvtVector4R& d1,const EvtVector4R& d2); | |
41 | ||
42 | ||
43 | ||
44 | // Added by AJB | |
45 | // | |
46 | // Calculate phi (between 0 and 2 pi) of the daughter given the 4-momentum of | |
47 | // the grandparent, parent, resonance and the daughter. g, p, q and d need to | |
48 | // be in the same rest frame. Note that for the first level of the tree there | |
49 | // is no grandparent and thus <0,0,0,1> should be passed in for g. When there | |
50 | // is no parent the angles need to be calculated by simply by calculating polar | |
51 | // and azymuthal angles in the rest frame of the resonance (since this will | |
52 | // generally be the root particle and is generally at rest the polar and | |
53 | // azymuthal angels can simply be calculated. | |
54 | // | |
55 | double EvtDecayAnglePhi( const EvtVector4R& g, const EvtVector4R& p, | |
56 | const EvtVector4R& q, const EvtVector4R& d ); | |
57 | ||
58 | // Wigner big-D function in Jackson convention | |
59 | // | |
60 | // XXX NOTE XXX | |
61 | // - EvtDecayAngle returns the cos \theta and EvtdFunction requires theta | |
62 | // - In EvtdFunction j m1 and m2 are really 2 * j, 2 * m1, 2*m2 to deal with | |
63 | // spin 1/2 particles | |
64 | // | |
65 | EvtComplex wignerD( int j, int m1, int m2, double phi, double theta, | |
66 | double gamma ); | |
67 | ||
68 | ||
69 | #endif | |
70 | ||
71 | ||
72 | ||
73 | ||
74 | ||
75 | ||
76 |