Line data Source code
1 : // WeakShowerMEs.cc is a part of the PYTHIA event generator.
2 : // Copyright (C) 2015 Torbjorn Sjostrand.
3 : // PYTHIA is licenced under the GNU GPL version 2, see COPYING for details.
4 : // Please respect the MCnet Guidelines, see GUIDELINES for details.
5 :
6 : // Function definitions (not found in the header) for the
7 : // WeakShowerMEs class.
8 :
9 : #include "Pythia8/WeakShowerMEs.h"
10 :
11 : namespace Pythia8 {
12 :
13 : //==========================================================================
14 :
15 : // The WeakShowerMEs class.
16 :
17 : //--------------------------------------------------------------------------
18 :
19 : // Calculate the 2 to 2 ME uG -> uG, with an overall factor of
20 : // g_s^4 / 9 was removed.
21 :
22 : double WeakShowerMEs::getTchanneluGuGME(double sHat, double tHat,
23 : double uHat) {
24 :
25 0 : double sH2 = sHat* sHat;
26 0 : double sH3 = sH2 * sHat;
27 0 : double tH2 = tHat * tHat;
28 0 : double uH2 = uHat * uHat;
29 0 : return (18.*sH3*uHat - 4*tH2*uH2 + 9*sHat*uH2*(tHat + 2*uHat) +
30 0 : sH2*(-4.*tH2 + 9*tHat*uHat + 18*uH2))/(sHat*tH2*uHat);
31 :
32 : }
33 :
34 : //--------------------------------------------------------------------------
35 :
36 : // Calculate the 2 to 2 ME ud -> ud, with an overall factor of
37 : // g_s^4 / 9 was removed.
38 :
39 : double WeakShowerMEs::getTchannelududME(double sHat, double tHat,
40 : double uHat) {
41 :
42 0 : double sH2 = sHat * sHat;
43 0 : double tH2 = tHat * tHat;
44 0 : double uH2 = uHat * uHat;
45 0 : return 4.*(sH2+uH2)/tH2;
46 :
47 : }
48 :
49 : //--------------------------------------------------------------------------
50 :
51 : // Calculate the 2 to 2 ME uu -> uu, with an overall factor of
52 : // g_s^4 / 9 was removed.
53 :
54 : double WeakShowerMEs::getTchanneluuuuME(double sHat, double tHat,
55 : double uHat) {
56 :
57 0 : double sH2 = sHat * sHat;
58 0 : double tH2 = tHat * tHat;
59 0 : double uH2 = uHat * uHat;
60 0 : return 4./2.*((sH2+uH2)/tH2 + (sH2+tH2)/uH2 - 2.*sH2/(3.*tHat*uHat));
61 :
62 : }
63 :
64 : //--------------------------------------------------------------------------
65 :
66 : // Calculate the 2 to 3 ME uG -> uGZ, with an overall factor of
67 : // \frac{(g_s^4 * 4\pi \alpha_{em} * (lU^2 + rU^2))}{
68 : // 9 * \cos^2(\theta_W) \sin^2(\theta_W)}$ was removed.
69 : // p1 = incoming quark, p2 = incoming gluon, p3 = outgoing gluon,
70 : // p4 = outgoing Z, p5 = outgoing quark.
71 :
72 : double WeakShowerMEs::getTchanneluGuGZME(Vec4 p1, Vec4 p2, Vec4 p3,
73 : Vec4 p4, Vec4 p5) {
74 :
75 0 : double p12 = p1*p2;
76 0 : double p13 = p1*p3;
77 0 : double p14 = p1*p4;
78 0 : double p23 = p2*p3;
79 0 : double p24 = p2*p4;
80 0 : double p44 = p4*p4;
81 0 : double p12P = (p1 + p2).m2Calc();
82 0 : double p13M = (p1 - p3).m2Calc();
83 0 : double p14M = (p1 - p4).m2Calc();
84 0 : double p23M = (p2 - p3).m2Calc();
85 0 : double p25M = (p2 - p5).m2Calc();
86 0 : double p35P = (p3 + p5).m2Calc();
87 0 : double p45P = (p4 + p5).m2Calc();
88 0 : double p44S = p44*p44;
89 :
90 0 : double dia1 = (-4*p12*(p12* (p44 - 2*p24) -p23 * (p44 - 2*p24) +2*p13*p24))
91 0 : / pow2(p12P * p45P);
92 :
93 0 : double dia2 = -(((p12 - p13 - p23) * (p12 * (p44 - 2*p14)
94 0 : - p13 * (p44 - 2*p14) + 2*p14*p23)) / (p12P * p13M * pow2(p45P)));
95 :
96 0 : double dia3 = (8*(p44 - 2*p12) * p12 * (p12 - p23 - p24))
97 0 : / (pow2(p12P) * p35P * p45P);
98 :
99 0 : double dia4 = -(8*pow3(p12) + 2*pow2(p12) * (p44 - 6*p13 - 6*p14 - 6*p23
100 0 : - 4*p24) + 4*pow2(p13) * (p44 - 2*p14 - p24) - 2*p14*p23
101 0 : * (-p44 + 2*p14 + 2*p23 + 4*p24) + 2*p13 * (-4*pow2(p14)
102 0 : + 2*p14 * (p44 - 3*p23 - 3*p24) + 2*p23 * (p44 - p24) + p44*p24)
103 0 : + p12* (p44S + 4*pow2(p13) + 4*pow2(p14) + 4*pow2(p23) - 4*p14
104 0 : * (p44 - 4*p23 - 3*p24) - 4*p13* (p44 - 4*p14 - 4*p23 - 3*p24)
105 0 : - 2*p44*p24 + 4*p23*p24)) / (4. * p12P * p13M * p25M * p45P);
106 :
107 0 : double dia5 = (-9*(2*pow3(p12) + (p13 + p23) * (-(p14* p23)
108 0 : + p13 * (p44 - 2*p14 - p24)) + pow2(p12)* (2*p44 - 4*p13 - 3*p14
109 0 : - 4*p23 - 3*p24) + p12 * (2*pow2(p13) + p23 * (-p44 + 4*p14
110 0 : + 2*p23 + 3*p24) + p13 * (-2*p44 + 5*p14 + 4*p23 + 4*p24))))
111 0 : / (p12P * p23M* pow2(p45P));
112 :
113 0 : double dia6 = (-4*(2*pow3(p12) + pow2(p12)* (7*p44 - 4*p13 - 6*p14
114 0 : - 2*p23 - 4*p24) + p12 * (2*pow2(p13) + 4*pow2(p14) - 2*p44*p23
115 0 : - 3*p44*p24 + 2*p23* p24 + 2*pow2(p24) + p14 * (-8*p44 + 6*p23 + 2*p24)
116 0 : + p13* (-7*p44 + 10*p14 + 6*p23 + 6*p24)) + 2*(pow2(p13) * (p44
117 0 : - 2*p14 - p24) + p14* (p14* (p44 - 2*p23) + p23 * (p44 - p24) + p44*p24)
118 0 : + p13 * (-2*pow2(p14) + p23 * (p44 - 2*p24) + p14* (2*p44 - 3*p23
119 0 : - 2*p24) + (p44 - p24)* p24)))) / (p12P * p14M * p35P * p45P);
120 :
121 0 : double dia7 = ((p12 - p13 - p14) * (p44 - 2*p23) * (p12 - p13 - p14
122 0 : - p23 - p24)) / (p12P * p14M * p25M * p45P);
123 :
124 0 : double dia8 = (9*(2*pow2((p1*p2))* (p44 - 10*p14 - 16*p23 + 4*p24)
125 0 : + p12* (p44S + 20*pow2(p14) - 6*p44*p23 + 16*pow2(p23)
126 0 : + p13* (-18*p44 + 28*p14 + 32*p23 - 8*p24) + 2*p44*p24
127 0 : + 16*p23* p24 - 8*pow2(p24) + p14* (-8*p44 + 52*p23 + 4*p24))
128 0 : + 2*(4*pow2(p13)* (p44 - p14 - 2*p23) - p14*p23* (-3*p44 + 10*p14
129 0 : + 8*p23 + 8*p24) + p13* (-4*pow2(p14) - 8*pow2(p23) + 4*p23* (p44 - p24)
130 0 : + 2*p14* (2*p44 - 8*p23 + p24) + p24* (p44 + 4*p24)))))
131 0 : / (8. * p12P * p23M * p14M * p45P);
132 :
133 0 : double dia9 = (-4*p13* (2*pow2(p12) + p12* (p44 - 4*p13 - 2*p14
134 0 : - 4*p23 - 2*p24) + 2*(p13 + p23)* (p13 + p14 + p23 + p24)))
135 0 : / (pow2(p13M) * pow2(p45P));
136 :
137 0 : double dia10 = (4*pow3(p12) - 4*pow2(p12) * (3*p13 + 2*p14 + 2*p23 + p24)
138 0 : + p12* (p44S + 8*pow2(p13) + 4*pow2(p14) + 4*pow2(p23)
139 0 : - 4*p14* (p44 - 3*p23 - 3*p24) - 2*p44*p24 + 4*p23*p24
140 0 : + p13* (-6*p44 + 20*p14 + 4*p23 + 12*p24)) + 2*(p14*p23* (p44
141 0 : - 2*p14 - 2*p23 - 4*p24) + 2*pow2(p13)* (p44 - 2*p14 - 2*p24)
142 0 : + p13* (-4*pow2(p14) + 2*p14* (p44 - 2*p23 - 3*p24)
143 0 : + 2*p23* (p44 - p24) + p44*p24))) / (4. * p12P * p13M * p35P* p45P);
144 :
145 0 : double dia11 = (4*p13* (p44 + 2*p13)* (p44 + 2*p12 - 2*p14 - 2*p24))
146 0 : / (pow2(p13M)* p25M * p45P);
147 :
148 0 : double dia12 = (-9*(-2*pow3(p12) + 2*pow3(p13) - 2*p14* pow2(p23)
149 0 : + pow2(p12)* (p44 + 6*p13 - 2*p14 + 4*p23 + 2*p24) + p13*p23
150 0 : * (-p44 - 2*p14 + 2*p23 + 6*p24) + pow2(p13)* (p44 + 4*p23 + 6*p24)
151 0 : - p12* (6*pow2(p13) + p23* (p44 - 4*p14 + 2*p23 + 2*p24)
152 0 : + p13* (-2*p14 + 8*(p23 + p24))))) / (2.* p13M * p23M * pow2(p45P));
153 :
154 0 : double dia13 = -((p12 - p13 - p14)* (p44 - 2*p23)* (p44 - 2*p24))
155 0 : / (2. * p13M * p14M * p35P * p45P);
156 :
157 0 : double dia14 = (2*(-8*pow2(p13)* (p44 - p14) - 2*pow2(p12)
158 0 : * (p44 - 2*p14 + 2*p23 - 2*p24) + 2*p14* (-p44S - 2*pow2(p23)
159 0 : + p23 * (p44 + 2*p14 - 2*p24) + 2*p44*p24) + p12* (p44S
160 0 : - 4*pow2(p14) + 4*pow2(p23) + 2*p13* (3*p44 - 6*p14 - 2*p23 - 2*p24)
161 0 : - 4*pow2(p24)) + p13* (-2*p44S + 8*pow2(p14) + 2*(p44 + 2*p23)* p24
162 0 : + 4*pow2(p24) + p14* (-8*p44 + 8*p23 + 4*p24))))
163 0 : / (p13M * p14M * p25M * p45P);
164 :
165 0 : double dia15 = (-9*(8*pow3(p12) + 2*pow2(p12)* (p44 - 8*p13 - 2*p14
166 0 : - 4*p23 - 8*p24) + p12* (3*p44S + 8*pow2(p13) - 4*pow2(p14)
167 0 : - 6*p44*p23 - 10*p44*p24 + 24*p23* p24 + 8*pow2(p24) + 4*p14
168 0 : * (p23 + 3*p24) + 2*p13 * (3*p44 - 2*p14 + 8*p23 + 12*p24))
169 0 : + 2*(p14*p23 * (p44 + 2*p14 - 8*p24) + 4*pow2(p13)* (p14
170 0 : + p23 - p24) + p13* (4*pow2(p14) - 4*pow2(p23)
171 0 : + 4*p23* (p44 - 4*p24) - 10*p14* p24 + (3*p44 - 4*p24)* p24))))
172 0 : / (8. * p13M * p23M * p14M * p45P);
173 :
174 0 : double dia16 = (4*p12*p23* (p44 + 2*p12 - 2*p14 - 2*p24))
175 0 : / (pow2(p12P) * pow2(p35P));
176 :
177 0 : double dia17 = ((p12 - p13 - p14)* (p44 - 2*p24)
178 0 : * (p12 - p13 - p14 - p23 - p24)) / (p12P * p13M * p25M * p35P);
179 :
180 0 : double dia18 = (9*(-20*pow3(p12) + 4*pow2(p12)* (4*p44 + p13 + 2*p14
181 0 : + p23) + 2*p14*p23* (p44 + 2*p14 - 4*p23 - 2*p24) + 8*pow2(p13)
182 0 : * (p44 - p14 - p24) + p13* (-8*pow2(p14) + 8*p44*p23
183 0 : + 4*p14* (2*p44 - 2*p23 - 5*p24) + 6*p44*p24 - 4*pow2(p24))
184 0 : + p12* (p44S - 4*pow2(p14) - 14*p44*p23 + 8*pow2(p23)
185 0 : - 8*p14* (p44 - p23 - 2*p24) - 12*p44*p24 + 12*p23* p24
186 0 : + 4*pow2(p24) + p13 * (-22*p44 + 20*p14 - 8*p23 + 24*p24))))
187 0 : / (8. * p12P * p23M * p35P * p45P);
188 :
189 0 : double dia19 = (-8*p13* (p44 + 2*p12 - 2*p14 - 2*p24)*(p12 - p14 - p24))
190 0 : / (p12P * p14M * pow2(p35P));
191 :
192 0 : double dia20 = (-8*pow3(p12) - p12* (4*pow2(p13) + 4*pow2(p14)
193 0 : - 4*p14* (p44 - 3*p23 - 4*p24) - 4*p13* (p44 - 4*p14 - 3*p23 - 4*p24)
194 0 : + (p44 - 2*p24)* (p44 - 2*p23 - 2*p24)) - 2*pow2(p12)
195 0 : * (p44 - 6*p13 - 6*p14 - 4*p23 - 6*p24) + 2*p14*p23
196 0 : * (-p44 + 2*p14 + 2*p24) + pow2(p13) * (-4*p44 + 8*p14 + 4*p24)
197 0 : + p13* (8*pow2(p14) - 4*p14* (p44 - 3*p23 - 3*p24) - 2*(p44 - 2*p24)
198 0 : * (2*p23 + p24))) / (4. * p12P * p14M * p25M* p35P);
199 :
200 0 : double dia21 = (-9*(14*pow3(p12) + pow2(p12)* (7*p44 - 10*p13 - 30*p14
201 0 : - 10*p23 - 22*p24) + 2*p12 * (2*pow2(p13) + 12*pow2(p14) - p44*p23
202 0 : - 3*p44*p24 + 2*p23* p24 + 4*pow2(p24) + p13* (-4*p44 + 10*p14
203 0 : + 6*p23 + 5*p24) + p14* (-5*p44 + 7*p23 + 16*p24)) + 2*(2*pow2(p13)
204 0 : * (p44 - 2*p14 - p24) + p13* (-4*pow2(p14) + 2*p23* (p44 - 2*p24)
205 0 : + 2*p14* (p44 - 3*p23 - 2*p24) + p44*p24) + p14* (-4*pow2(p14)
206 0 : + 2*p14* (p44 - p23 - 3*p24) + p23* (p44 - 2*p24)
207 0 : + 2*(p44 - p24)* p24)))) / (4. * p12P * p23M * p14M* p35P);
208 :
209 0 : double dia22 = (-8*p13*p23* (-p12 + p23 + p24))
210 0 : / (pow2(p13M)* pow2(p25M));
211 :
212 0 : double dia23 = (-9*(2*pow3(p12) - pow2(p12)* (p44 + 10*p13 + 6*p14)
213 0 : + p12* (p44S + 8*pow2(p13) + 4*pow2(p14) + 3*p44*p23 - 2*pow2(p23)
214 0 : - p44*p24 - 4*p23 * p24 - 2*pow2(p24) + 2*p13* (6*p14 + 7*p23 + 2*p24)
215 0 : + p14* (-2*p44 + 4*p23 + 6*p24)) - 2*(4*pow3(p13) + 2*pow2(p13)
216 0 : * (p44 + 2*p14 + p23 - p24) + p14*p23* (2*p14 - p23 + p24)
217 0 : + p13 * (p44S + 4*pow2(p14) + (-2*p44 + p23)* p24 - pow2(p24)
218 0 : + p14* (-2*p44 + 4*p23 + 2*p24))))) / (4. * p13M * p23M * p25M * p45P);
219 :
220 0 : double dia24 = (-2*pow2(p12)* (p44 + p13 + p23 - p24) + p12* (2*pow2(p13)
221 0 : - p13* (p44 - 6*p14) + (p44 + 2*p14 + 2*p23 - 2*p24)* (p23 + p24))
222 0 : + 2*(pow2(p13)* (p44 - 2*p14 - p24) - p14*p23 * (p23 + p24)
223 0 : + p13* (-2*pow2(p14) + p14 * (p44 - p23 - 2*p24) + p24* (p23 + p24))))
224 0 : / (2. * p13M * p14M * p25M* p35P);
225 :
226 0 : double dia25 = (8*p12* (p44 + 2*p12 - 2*p23 - 2*p24)*(p12 - p23 - p24))
227 0 : / (p13M * p14M * pow2(p25M));
228 :
229 0 : double dia26 = (9*(4*pow3(p12) + 2*pow2(p13)* (p44 - 2*p14 - 3*p24)
230 0 : - 2*pow2(p12)* (p13 + 6*p23 + 2*p24) + p12* (p44S + 6*pow2(p13)
231 0 : - 2*p44*p14 + 4*pow2(p14) - 2*p44*p23 + 8*pow2(p23) + 3*p13
232 0 : * (p44 + 2*p14 - 2*p23 - 2*p24) - 2*p44*p24 + 8*p23*p24)
233 0 : + p14* (-p44S + 2*p14* (p44 - 2*p23 - 2*p24) + 4*p23* p24
234 0 : + 4*pow2(p24)) - p13 * (p44S + 4*pow2(p14) - 4*pow2(p23)
235 0 : + 2*p23 * (p44 - 6*p24) + 2*p44*p24 - 8*pow2(p24)
236 0 : + p14* (-4*p44 + 2*p23 + 8*p24)))) / (4. * p13M * p23M * p14M * p25M);
237 :
238 0 : double dia27 = (-9*(3*pow3(p12) - pow3(p13) + p14 * pow2(p23)
239 0 : + pow2(p12)* (p44 - 7*p13 - 3*p14 - 6*p23 - 2*p24) - p13*p23
240 0 : * (2*p44 + p23 - 2*p24) - pow2(p13)* (p14 + 2*p23 - 2*p24)
241 0 : + p12 * (5*pow2(p13) + p13* (p44 + 4*p14 + 8*p23)
242 0 : + p23 * (p44 + 2*p14 + 3*p23 + 2*p24)))) / (pow2(p23M) * pow2(p45P));
243 :
244 0 : double dia28 = (9*(2*pow3(p12) - pow2(p12)* (p44 + 4*p13 + 10*p14
245 0 : + 8*p23 - 2*p24) + 2*pow2(p13)* (p44 - 2*p14 - p24) + p14* (p44S
246 0 : + 2*p44*p23 + 2*pow2(p23) - 2*p14* (p44 + 6*p23) - 4*p44*p24)
247 0 : + p12* (-p44S + 2*pow2(p13) + 8*pow2(p14) + p13 * (-5*p44 + 14*p14)
248 0 : - 3*p44*p23 - 2*pow2(p23) + 2*p14* (p44 + 10*p23) + 6*p44*p24
249 0 : + 2*p23* p24 - 4*pow2(p24)) + p13* (-4*pow2(p14) + pow2(p44 - 2*p24)
250 0 : + 2*p23* (p44 + p24) + p14* (-6*p23 + 4*p24))))
251 0 : / (4. * p23M * p14M * p35P * p45P);
252 :
253 0 : double dia29 = (-9*(6*pow3(p12) - 2*pow2(p13)* (p44 - 2*p14 + 3*p24)
254 0 : - pow2(p12)* (p44 + 12*p13 + 2*p14 + 8*p23 + 10*p24) + p14* (p44S
255 0 : - 2*p14* (p44 - 6*p23) - 6*p44*p23 - 2*pow2(p23) - 4*p44*p24)
256 0 : + p13* (p44S + 4*pow2(p14) - 8*pow2(p23) - 2*p44* p24 - 4*pow2(p24)
257 0 : - 2*p14* (2*p44 - 5*p23 + 4*p24) - 2*p23* (2*p44 + 5*p24))
258 0 : + p12* (6* pow2(p13) - 4*pow2(p14) + 3*p44*p23 + 2*pow2(p23)
259 0 : + 6*p23* p24 + 4*pow2(p24) + p14 * (6*p44 - 4*p23 + 4*p24)
260 0 : + p13* (7*p44 - 2*p14 + 16*p23 + 16*p24))))
261 0 : / (4. * p23M * p14M * p25M * p45P);
262 :
263 0 : double dia30 = (-9*(4*pow3(p12) + 2*pow2(p12)* (p44 - 4*p13 + 2*p14
264 0 : - 6*p24) + p12* (p44S + 4*pow2(p13) - 8*pow2(p14) - 6*p44*p23
265 0 : + 12*pow2(p23) - 6*p44 *p24 + 4*p23* p24 + 8*pow2(p24) + 2*p14
266 0 : * (p44 - 4*p23 + 2*p24) + 8*p13* (p44 - p14 + 2*p23 + 2*p24))
267 0 : - 2*(-2*p14* (p44 + 2*p14 - 3*p23)* p23 + pow2(p13)* (p44 - 2*p14
268 0 : + 2*p24) + p13 * (-2*pow2(p14) + 8*pow2(p23) - 3*p23* (p44 - 2*p24)
269 0 : + p24* (-p44 + 4*p24) + p14* (p44 + 6*p24)))))
270 0 : / (2. * pow2(p23M) * p14M * p45P);
271 :
272 0 : double dia31 = (-2*(p13* (p44 - 2*p14) + p14* (p44 + 2*p12 - 2*p14
273 0 : - 2*p23 - 2*p24))* (p44 + 2*p12 - 2*p14 - 2*p24))
274 0 : / (pow2(p14M) * pow2(p35P));
275 :
276 0 : double dia32 = -((p44 - 2*p14)* (p12* (p44 - 2*p14) - p13* (p44 - 2*p14)
277 0 : + 2*p14*p23)) / (2. * pow2(p14M) * p25M * p35P);
278 :
279 0 : double dia33 = (-9*(4*pow3(p14) + 2*pow2(p12)* (p44 + 2*p14)
280 0 : - 4*pow2(p14)* (p44 + p23 - 3*p24) - 2*p44*p13* p24
281 0 : + p14* (p44S + 2*p44*p23 + (-6*p44 + 4*p13)* p24 + 8*pow2(p24))
282 0 : + p12 * (2*p13* (p44 - 2*p14) + p44*(3*p44 + 2*p23 - 2*p24)
283 0 : - 2*p14* (3*p44 + 2*p23 + 6*p24)))) / (4. * p23M * pow2(p14M) * p35P);
284 :
285 0 : double dia34 = (-4*(p12 - p23 - p24)* (p44*p12-2*p14*p24))
286 0 : / (pow2(p14M)* pow2(p25M));
287 :
288 0 : double dia35 = (-9*(2*pow2(p12)* (p44 + 2*p14) - 2*p13 * (p44 - 2*p14)
289 0 : * (p44 - 2*p14 + 2*p23 + p24) + 2*p14* (4*pow2(p23) + 8*p23* p24
290 0 : + p24* (-p44 + 2*p14 + 4*p24)) + p12* (2*p13* (p44 - 2*p14)
291 0 : + p44*(p44 - 2*p23 - 2*p24) - 2*p14* (p44 + 6*p23 + 6*p24))))
292 0 : / (4. * p23M * pow2(p14M) * p25M);
293 :
294 0 : double dia36 = (-9*(4*pow2(p12)* (p44 + 2*p14) - p13 * (p44 - 2*p14)
295 0 : * (p44 - 2*p14 + 8*p23 + 4*p24) + p14* (-p44S - 4*pow2(p14)
296 0 : + 16*pow2(p23) - 4*p23 * (p44 - 4*p24) - 8*p44*p24 + 16*pow2(p24)
297 0 : + 4*p14* (p44 + 2*p23 + 4*p24)) + p12* (4*p13 * (p44 - 2*p14)
298 0 : - 4*pow2(p14) + p44*(3*p44 + 4*p23 - 4*p24) - 4*p14* (p44 + 6*p23
299 0 : + 6*p24)))) / (4. * pow2(p23M) * pow2(p14M));
300 :
301 0 : return dia1 + dia2 + dia3 + dia4 + dia5 + dia6 + dia7 + dia8 + dia9
302 0 : + dia10 + dia11 + dia12 + dia13 + dia14 + dia15 + dia16 + dia17 + dia18
303 0 : + dia19 + dia20 + dia21 + dia22 + dia23 + dia24 + dia25 + dia26 + dia27
304 0 : + dia28 + dia29 + dia30 + dia31 + dia32 + dia33 + dia34 + dia35 + dia36;
305 :
306 0 : }
307 :
308 : //--------------------------------------------------------------------------
309 :
310 : // Calculate the 2 to 3 ME ud -> udZ, with the coupling between Z and d
311 : // set to zero. An overall factor of
312 : // \frac{(g_s^4 * 4\pi \alpha_{em} * (lU^2 + rU^2))}{
313 : // 9 * \cos^2(\theta_W) \sin^2(\theta_W)}$ was removed.
314 : // p1 = incoming u, p2 = incoming d, p3 = outgoing Z,
315 : // p4 = outgoing d, p5 = outgoing u.
316 :
317 : double WeakShowerMEs::getTchannelududZME(Vec4 p1,Vec4 p2,Vec4 p3,
318 : Vec4 p4,Vec4 p5) {
319 :
320 0 : double p12 = p1*p2;
321 0 : double p13 = p1*p3;
322 0 : double p14 = p1*p4;
323 0 : double p23 = p2*p3;
324 0 : double p24 = p2*p4;
325 0 : double p33 = p3*p3;
326 0 : double p13M = (p1 - p3).m2Calc();
327 0 : double p24M = (p2 - p4).m2Calc();
328 0 : double p35P = (p3 + p5).m2Calc();
329 0 : double p33S = p33*p33;
330 :
331 0 : double dia1 = (-4*(2*pow3(p12) + pow2(p12) * (p33 - 2*p13 - 4*p14
332 0 : - 2*p23 - 4*p24) + p14* (2*p14* p23 - (p33 - 2*p23)* p24)
333 0 : + p12 * (2*pow2(p14) + 2*p24* (p13 + p23 + p24)
334 0 : + p14* (p33 + 2*p13 + 4*p24)))) / pow2(p24M* p35P);
335 :
336 0 : double dia2 = (-2*(4*pow3(p12) + 4*pow2(p12)
337 0 : * (p33 - 2*p14 - 3*p23) + p12 * (p33S - 4*pow2(p13) + 4*pow2(p14)
338 0 : - 6*p33*p23 + 8*pow2(p23) + 4*p13 * (p23 - p24) - 4*p33*p24 + 4*p23
339 0 : * p24 + 4*pow2(p24) + 4*p14* (p33 + 4*p23 + 4*p24)) + 2*(-2*pow2(p14)
340 0 : * p23 + p13* (p33 + 2*p13 - 2*p24) * p24 + p14* (-4*pow2(p23) + p23
341 0 : * (p33 - 6*p13 - 6*p24) + 2*(p33 - p13 - 2*p24)* p24))))
342 0 : / (p13M * pow2(p24M) * p35P);
343 :
344 0 : double dia3 = (-2*(2*pow2(p12)* (p33 + 2*p13)
345 0 : - 2*p33*p14* (p23 + p24) + 4*pow2(p13)* (2*p23 + p24) + p12
346 0 : * (-4*pow2(p13) + p33*(p33 + 2*p14 - 2*p23) - 4*p13* (p14 + 3*p23
347 0 : + 2*p24)) + p13* (8*pow2(p23) + 2*p24 * (-p33 + 2*p14 + 2*p24) + p23
348 0 : * (-4*p33 + 4*p14 + 8*p24)))) / pow2(p13M * p24M);
349 :
350 0 : return dia1 + dia2 + dia3;
351 :
352 0 : }
353 :
354 : //==========================================================================
355 :
356 : } // end namespace Pythia8
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