C++ Interface to Tauola
new.f
1************************************************************************
2* default Tauola resonance form factor (taken from tauola function
3* FORM1):
4************************************************************************
5 xm2 = 1.402
6 gam2 = 0.174
7 form1 = fpikm(sqrt(s1),ampi,ampi)
8 form1 = form1*wigfor(qq,xm2,gam2)
9************************************************************************
10* new form factor taking into account phase space limitations
11* for decay K1(1270)->rho(770) K :
12************************************************************************
13 xm2 = 1.270
14 gam2 = 0.090
15 amres = amro
16 gamres = gamro
17 am3 = ampi
18 am2 = ampi
19 am1 = amk
20 l1 = 0
21 l2 = 1
22 form1 = bwigk1(qq,xm2,gam2,amres,gamres,am3,am2,am1,l1,l2)
23 form1 = form1*bwigkst(s1,amres,gamres,am2,am3,l2)
24
25************************************************************************
26* L-DEPENDENT BREIT WIGNER FOR K1. TAKES INTO ACCOUNT CASES WHERE
27* ONLY A PORTION OF THE BW OF THE SECONDARY RESONANCE IS KINEMATICALLY
28* ACCESSIBLE (IE; K1(1270)->RHOK).
29*
30* SQRT(S) = SAMPLED K1 MASS
31* M = MASS OF K1 (1270 or 1410)
32* G = WIDTH OF K1
33* XMRES0 = MASS OF SECONDARY RESONANCE
34* GAM0 = WIDTH OF SECONDARY RESONANCE
35* XMRES1 = MASS OF FIRST DAUGHTER OF SECONDARY RESONANCE
36* XMRES2 = MASS OF SECOND DAUGHTER OF SECONDARY RESONANCE
37* XMLEFT = MASS OF SECOND DAUGHTER OF PRIMARY RESONANCE
38*
39* FORM TAKEN FROM MANLEY ET AL, 'Multichannel resonance parameterisation
40* of piN scattering amplitudes', Phys Rev D, vol 45, 4002-4033 (1992).
41*
42* L1 IS THE ANG-MOM OF PRIMARY DECAY
43* L2 IS ANG-MOM OF DECAY OF SECONDARY RESONANCE (RHO OR K*)
44*
45* Created: 1997
46* Author: Sherry Towers
47************************************************************************
48+deck,bwigk1.
49 COMPLEX FUNCTION bwigk1(S,M,G,XMRES0,XGAM0,XMRES1,XMRES2,XMLEFT
50 * ,L1,L2)
51 IMPLICIT NONE
52 real
53 * s,m,g
54 * ,xmres1,xmres2,xmleft
55 * ,mres1,mres2,mleft
56 * ,gam
57 * ,eps,w
58 * ,xmres0,xgam0
59 * ,mres0,gamres
60 * ,rhok1,rhos
61 * ,a,b,c
62
63 INTEGER L1,L2,N1,N2
64 REAL GAUSS ! CERNLIB GAUSSIAN INTEGRATION ROUTINE
65 EXTERNAL gauss
66 REAL FUNC
67 EXTERNAL func
68
69 COMMON /k1mass/ w,mres0,gam0,mres1,mres2,mleft,n1,n2
70
71 COMPLEX WIGNER
72 wigner(a,b,c)= cmplx(1.0,0.0)/cmplx(a-b**2,b*c)
73
74 n1 = l1
75 n2 = l2
76 mres0 = xmres0
77 gam0 = xgam0
78 mres1 = xmres1
79 mres2 = xmres2
80 mleft = xmleft
81
82 eps = 0.00001
83 w = m
84 rhok1 = gauss(func,xmres1+xmres2,m-xmleft,eps)
85 w = sqrt(s)
86 rhos = gauss(func,xmres1+xmres2,sqrt(s)-xmleft,eps)
87 gam = g*(rhos/rhok1)
88 bwigk1 = (m**2)*wigner(s,m,gam)
89
90 RETURN
91 END
92
93************************************************************************
94************************************************************************
95* Created: 1997
96* Author: Sherry Towers
97************************************************************************
98+deck,func.
99 REAL FUNCTION FUNC(X)
100 IMPLICIT NONE
101 real
102 * x,w
103 * ,mres0,mres1,mres2,mleft
104 * ,gam,gam0
105 * ,q,q0
106 * ,pival
107 * ,bwig
108 INTEGER L1,L2
109 COMMON /k1mass/ w,mres0,gam0,mres1,mres2,mleft,l1,l2
110
111 pival = acos(-1.0)
112
113 l2 = 1
114 IF (x.GT.(mres1+mres2)) THEN
115 q0 = (mres0**2-(mres1+mres2)**2)*(mres0**2-(mres1-mres2)**2)
116 q0 = sqrt(q0)/(2.0*mres0)
117
118 q = (x**2-(mres1+mres2)**2)*(x**2-(mres1-mres2)**2)
119 q = sqrt(q)/(2.0*x)
120
121 gam = gam0*(q/q0)**(2*l2+1)
122 bwig = (x-mres0)**2 + (gam/2.0)**2
123 bwig = (gam/(2.0*pival))/bwig
124 ELSE
125 bwig = 0.0
126 END IF
127
128 l1 = 0
129 q = (w**2-(mleft+x)**2)*(w**2-(mleft-x)**2)
130 q = sqrt(q)/(2.0*w)
131
132 func = bwig*(q)**(2*l1+1)/w
133
134 RETURN
135 END
136************************************************************************
137************************************************************************
138* L-DEPENDENT BREIT WIGNER FOR KSTAR(1430),K*(892) or RHO(770)
139* Created: 1997
140* Author: Sherry Towers
141************************************************************************
142+deck,bwigkst.
143 COMPLEX FUNCTION bwigkst(S,M,G,XM1,XM2,L)
144 IMPLICIT NONE
145 real
146 * s,m,g
147 * ,xm1,xm2
148 * ,gam,q,q0
149 * ,a,b,c
150 INTEGER L
151 COMPLEX WIGNER
152 wigner(a,b,c)= cmplx(1.0,0.0)/cmplx(a-b**2,b*c)
153
154 IF (s.GT.(xm1+xm2)**2.AND.m.GT.(xm1+xm2)) THEN
155 q0 = (m**2-(xm1+xm2)**2)*(m**2-(xm1-xm2)**2)
156 q0 = sqrt(q0)/(2.0*m)
157
158 q = (s-(xm1+xm2)**2)*(s-(xm1-xm2)**2)
159 q = sqrt(q)/(2.0*sqrt(s))
160
161 gam = g*(q/q0)**(2*l+1)
162 bwigkst = (m**2)*wigner(s,m,gam)
163 ELSE
164 bwigkst = cmplx(0.0,0.0)
165 END IF
166
167 RETURN
168 END
169
170