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[u/mrichter/AliRoot.git] / ISAJET / code / sigh.F
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0795afa3 1#include "isajet/pilot.h"
2 SUBROUTINE SIGH
3C
4C COMPUTE THE INTEGRATED WEINBERG-SALAM HIGGS CROSS SECTION
5C D(SIGMA)/D(QMW**2)D(YW)
6C
7C SIGMA = CROSS SECTION SUMMED OVER QUARK TYPES ALLOWED BY
8C JETTYPE3 AND WTYPE CARDS.
9C SIGS(I) = PARTIAL CROSS SECTION FOR I1 + I2 --> I3 + I4.
10C INOUT(I) = IOPAK**3*I4 + IOPAK**2*I3 + IOPAK*I2 + I1
11C USING JETTYPE CODE.
12C
13C VER. 7.14: CHECK INITIAL QUARK MASS IS ALLOWED
14C
15#include "isajet/itapes.inc"
16#include "isajet/qcdpar.inc"
17#include "isajet/jetpar.inc"
18#include "isajet/primar.inc"
19#include "isajet/q1q2.inc"
20#include "isajet/jetsig.inc"
21#include "isajet/qsave.inc"
22#include "isajet/wcon.inc"
23#include "isajet/const.inc"
24#include "isajet/jetlim.inc"
25#include "isajet/hcon.inc"
26C
27 DIMENSION AMQCUR(6),LISTW(4),WTHELI(4),FINT(9)
28 DIMENSION X(2)
29 EQUIVALENCE (S,SHAT),(T,THAT),(U,UHAT),(X(1),X1)
30#if defined(CERNLIB_DOUBLE)
31 DOUBLE PRECISION C,TERM,SUM,FINT,ZLIM
32#endif
33 DATA AMQCUR/.005,.009,.175,1.25,4.50,30./
34 DATA LISTW/10,80,-80,90/
35C WTHELI ARE WEIGHTS OF HELICITY AMPLITUDES IN SIGMA.
36 DATA WTHELI/1.,2.,2.,4./
37C
38C FUNCTIONS
39 ACOSH(Z)=ALOG(Z+SQRT(Z**2-1.))
40 ATANH(Z)=.5*ALOG((1.+Z)/(1.-Z))
41C
42C KINEMATICS (IDENTICAL TO DRELL-YAN)
43C
44 AMQCUR(6)=AMASS(6)
45 QMW2=QMW**2
46 QTMW=SQRT(QMW2+QTW**2)
47 Q0W=QTMW*COSH(YW)
48 QZW=QTMW*SINH(YW)
49 QW=SQRT(QZW**2+QTW**2)
50 IF(QW.NE.0.) THEN
51 CTHW=QZW/QW
52 STHW=QTW/QW
53 IF(ABS(CTHW).LT.1.) THEN
54 THW=ACOS(CTHW)
55 ELSE
56 CTHW=0.
57 STHW=1.
58 THW=.5*PI
59 ENDIF
60 ELSE
61 CTHW=0.
62 STHW=1.
63 THW=.5*PI
64 ENDIF
65 EHAT=QMW
66 SHAT=QMW**2
67 QSQ=SHAT
68 ANEFF=4.+QSQ/(QSQ+AMASS(5)**2)+QSQ/(QSQ+AMASS(6)**2)
69 ALFQSQ=12.*PI/((33.-ANEFF)*ALOG(QSQ/ALAM2))
70 Q2SAVE=QSQ
71 YHAT=YW
72 EY=EXP(YHAT)
73 X1=EHAT/ECM*EY
74 X2=EHAT/(ECM*EY)
75C
76C INITIALIZE
77C
78 SIGMA=0.
79 NSIGS=0
80 DO 100 I=1,MXSIGS
81100 SIGS(I)=0
82C
83 IF(X1.GE.1..OR.X2.GE.1.) RETURN
84C
85C COMPUTE STRUCTURE FUNCTIONS
86 DO 110 IH=1,2
87 DO 120 IQ=1,13
88120 QSAVE(IQ,IH)=STRUC(X(IH),QSQ,IQ,IDIN(IH))/X(IH)
89 DO 130 IQ=14,26
90130 QSAVE(IQ,IH)=0.
91 DO 140 IW=2,4
92 AMW=AMASS(LISTW(IW))
93 IF(QMW.GT.2.*AMW) THEN
94 QSAVE(25+IW,IH)=STRUCW(X(IH),IW,IDIN(IH))/X(IH)
95 ELSE
96 QSAVE(25+IW,IH)=0.
97 ENDIF
98140 CONTINUE
99110 CONTINUE
100C
101C CALCULATE HIGGS-GLUON-GLUON COUPLING FOR GIVEN Q**2
102 ETAR=0.
103 ETAI=0.
104 DO 150 IQ=1,8
105 AMQ=AMASS(IQ)
106 IF(AMQ.LE.0.) GO TO 150
107 RQ=(2.*AMQ/HMASS)**2
108 IF(RQ.GE.1.) THEN
109 ETAR=ETAR+.5*RQ*(1.+(1.-RQ)*ASIN(1./SQRT(RQ))**2)
110 ELSE
111 RQLOG=ALOG((1.+SQRT(1.-RQ))/(1.-SQRT(1.-RQ)))
112 PHIR=.25*(RQLOG**2-PI**2)
113 ETAR=ETAR+.5*RQ*(1.+(RQ-1.)*PHIR)
114 PHII=.5*PI*RQLOG
115 ETAI=ETAI+.5*RQ*(RQ-1.)*PHII
116 ENDIF
117150 CONTINUE
118 ETAHGG=ETAR**2+ETAI**2
119C
120C GL + GL --> HIGGS
121C
122 SIG0=GF*ALFQSQ**2/(32.*PI*SQRT2)*ETAHGG*X1*X2*UNITS
123 SIG0=SIG0*S/(PI*HMASS*((S-HMASS**2)**2+(HMASS*HGAM)**2))
124 SIG0=SIG0*QSAVE(1,1)*QSAVE(1,2)
125 DO 160 IQ1=2,29
126 IQ2=MATCHH(IQ1)
127 IF(GOQ(IQ1,1).AND.GOQ(IQ2,2)) THEN
128 SIG=SIG0*HGAMS(IQ1)
129 IF(IQ1.GT.25) SIG=SIG*TBRWW(IQ1-25,1)*TBRWW(IQ2-25,2)
130 CALL SIGFIL(SIG,1,1,IQ1,IQ2)
131 ENDIF
132160 CONTINUE
133C
134C QK + QB --> HIGGS
135C
136 SIG0=PI*GF/(3.*SQRT2*HMASS**2)*X1*X2*UNITS
137 SIG0=SIG0*S/(PI*HMASS*((S-HMASS**2)**2+(HMASS*HGAM)**2))
138 DO 210 IQ1=2,13
139 IQ2=MATCHH(IQ1)
140 AMQ=AMQCUR(IQ1/2)
141 IF(QMW.LE.2*AMQ) GO TO 210
142 SIG1=SIG0*AMQ**2*QSAVE(IQ1,1)*QSAVE(IQ2,2)
143 DO 220 IQ3=2,29
144 IQ4=MATCHH(IQ3)
145 IF(GOQ(IQ3,1).AND.GOQ(IQ4,2)) THEN
146 SIG=SIG1*HGAMS(IQ3)
147 IF(IQ3.GT.25) SIG=SIG*TBRWW(IQ3-25,1)*TBRWW(IQ4-25,2)
148 CALL SIGFIL(SIG,IQ1,IQ2,IQ3,IQ4)
149 ENDIF
150220 CONTINUE
151210 CONTINUE
152C
153C W+W FUSION AND W+W->W+W IN EFFECTIVE W APPROXIMATION WITH
154C ANGULAR DISTRIBUTION CUT OFF BY PTMIN.
155C Z0 Z0 FINAL STATE HAS SYMMETRY FACTOR OF .5
156C
157 IF(QMW.LE.2.*AMASS(80)) GO TO 500
158C
159C W+ W- --> W+ W-
160C
161 IF(.NOT.((GOQ(27,1).AND.GOQ(28,2)).OR.(GOQ(28,1).AND.GOQ(27,2))))
162 $GO TO 400
163 WM=AMASS(80)
164 PWWCM=.5*SQRT(QMW**2-4.*WM**2)
165 STHLIM=PTMIN(1)/PWWCM
166 IF(STHLIM.LE.1) THEN
167 ZLIM=SQRT(1.-STHLIM**2)
168 ELSE
169 GO TO 400
170 ENDIF
171C SET UP AMPLITUDES
172 CALL XWWWW
173C SUM CROSS SECTION TERMS. I,J RUN OVER AMPLITUDE TERMS.
174C L RUNS OVER HELICITY STATES. N RUNS OVER POWERS.
175C REMEMBER THAT L=4 IS MISSING SIN(THETA)/SQRT(2)
176 SUM=0.
177 DO 311 I=1,4
178 DO 311 J=I,4
179 CALL SIGINT(FINT,ZLIM,ADWWWW(1,I),ADWWWW(2,I),ADWWWW(1,J),
180 $ADWWWW(2,J))
181 DO 312 L=1,4
182 TERM=0.
183 DO 313 N=0,6
184 C=0.
185 N1=MAX(N-3,0)
186 N2=MIN(3,N)
187 DO 314 K=N1,N2
188314 C=C+ANWWWW(K+1,I,L)*ANWWWW(N-K+1,J,L)
189 C=C*WTHELI(L)
190 IF(J.NE.I) C=2.*C
191 IF(L.EQ.4) THEN
192 TERM=TERM+.5*C*FINT(N+1)-.5*C*FINT(N+3)
193 ELSE
194 TERM=TERM+C*FINT(N+1)
195 ENDIF
196313 CONTINUE
197 SUM=SUM+TERM
198312 CONTINUE
199311 CONTINUE
200C ADD INTEGRAL OF IMAGINARY PART SQUARED.
201 SUM=SUM+2.*ZLIM*(WTHELI(1)*AIWWWW(1)**2+WTHELI(2)*AIWWWW(2)**2
202 $+WTHELI(3)*AIWWWW(3)**2+WTHELI(4)*AIWWWW(4)**2)
203C CROSS SECTION
204 SIG0=SUM/(32.*PI*S*SCM)*UNITS
205 SIG1=.5*SIG0*QSAVE(27,1)*QSAVE(28,2)
206 IF(GOQ(27,1).AND.GOQ(28,2)) THEN
207 SIG=SIG1*TBRWW(2,1)*TBRWW(3,2)
208 CALL SIGFIL(SIG,27,28,27,28)
209 ENDIF
210 IF(GOQ(28,1).AND.GOQ(27,2)) THEN
211 SIG=SIG1*TBRWW(3,1)*TBRWW(2,2)
212 CALL SIGFIL(SIG,27,28,28,27)
213 ENDIF
214 SIG1=.5*SIG0*QSAVE(28,1)*QSAVE(27,2)
215 IF(GOQ(27,1).AND.GOQ(28,2)) THEN
216 SIG=SIG1*TBRWW(2,1)*TBRWW(3,2)
217 CALL SIGFIL(SIG,28,27,27,28)
218 ENDIF
219 IF(GOQ(28,1).AND.GOQ(27,2)) THEN
220 SIG=SIG1*TBRWW(3,1)*TBRWW(2,2)
221 CALL SIGFIL(SIG,28,27,28,27)
222 ENDIF
223C
224C Z0 Z0 --> W+ W-
225C
226C SET UP AMPLITUDES
227 IF(QMW.LE.2.*AMASS(90)) GO TO 500
228 CALL XZZWW
229C SUM CROSS SECTION TERMS. I,J RUN OVER AMPLITUDE TERMS.
230C L RUNS OVER HELICITY STATES. N RUNS OVER POWERS.
231C REMEMBER THAT L=4 IS MISSING SIN(THETA)/SQRT(2)
232 SUM=0.
233 DO 321 I=1,4
234 DO 321 J=I,4
235 CALL SIGINT(FINT,ZLIM,ADWWWW(1,I),ADWWWW(2,I),ADWWWW(1,J),
236 $ADWWWW(2,J))
237 DO 322 L=1,4
238 TERM=0.
239 DO 323 N=0,6
240 C=0.
241 N1=MAX(N-3,0)
242 N2=MIN(3,N)
243 DO 324 K=N1,N2
244324 C=C+ANWWWW(K+1,I,L)*ANWWWW(N-K+1,J,L)
245 C=C*WTHELI(L)
246 IF(J.NE.I) C=2.*C
247 IF(L.EQ.4) THEN
248 TERM=TERM+.5*C*FINT(N+1)-.5*C*FINT(N+3)
249 ELSE
250 TERM=TERM+C*FINT(N+1)
251 ENDIF
252323 CONTINUE
253 SUM=SUM+TERM
254322 CONTINUE
255321 CONTINUE
256C ADD INTEGRAL OF IMAGINARY PART SQUARED.
257 SUM=SUM+2.*ZLIM*(WTHELI(1)*AIWWWW(1)**2+WTHELI(2)*AIWWWW(2)**2
258 $+WTHELI(3)*AIWWWW(3)**2+WTHELI(4)*AIWWWW(4)**2)
259C CROSS SECTION
260 SIG0=SUM/(32.*PI*S*SCM)*UNITS
261 SIG1=.5*SIG0*QSAVE(29,1)*QSAVE(29,2)
262 IF(GOQ(27,1).AND.GOQ(28,2)) THEN
263 SIG=SIG1*TBRWW(2,1)*TBRWW(3,2)
264 CALL SIGFIL(SIG,29,29,27,28)
265 ENDIF
266 IF(GOQ(28,1).AND.GOQ(27,2)) THEN
267 SIG=SIG1*TBRWW(3,1)*TBRWW(2,2)
268 CALL SIGFIL(SIG,29,29,28,27)
269 ENDIF
270C
271C W+ W- --> Z0 Z0
272C
273400 IF(QMW.LE.2.*AMASS(90)) GO TO 500
274 IF(.NOT.(GOQ(29,1).AND.GOQ(29,2))) GO TO 500
275 WM=AMASS(90)
276 PWWCM=.5*SQRT(QMW**2-4.*WM**2)
277 STHLIM=PTMIN(1)/PWWCM
278 IF(STHLIM.LE.1) THEN
279 ZLIM=SQRT(1.-STHLIM**2)
280 ELSE
281 GO TO 500
282 ENDIF
283C SET UP AMPLITUDES
284 CALL XWWZZ
285C SUM CROSS SECTION TERMS. I,J RUN OVER AMPLITUDE TERMS.
286C L RUNS OVER HELICITY STATES. N RUNS OVER POWERS.
287C REMEMBER THAT L=4 IS MISSING SIN(THETA)/SQRT(2)
288 SUM=0.
289 DO 411 I=1,4
290 DO 411 J=I,4
291 CALL SIGINT(FINT,ZLIM,ADWWWW(1,I),ADWWWW(2,I),ADWWWW(1,J),
292 $ADWWWW(2,J))
293 DO 412 L=1,4
294 TERM=0.
295 DO 413 N=0,6
296 C=0.
297 N1=MAX(N-3,0)
298 N2=MIN(3,N)
299 DO 414 K=N1,N2
300414 C=C+ANWWWW(K+1,I,L)*ANWWWW(N-K+1,J,L)
301 C=C*WTHELI(L)
302 IF(J.NE.I) C=2.*C
303 IF(L.EQ.4) THEN
304 TERM=TERM+.5*C*FINT(N+1)-.5*C*FINT(N+3)
305 ELSE
306 TERM=TERM+C*FINT(N+1)
307 ENDIF
308413 CONTINUE
309 SUM=SUM+TERM
310412 CONTINUE
311411 CONTINUE
312C ADD INTEGRAL OF IMAGINARY PART SQUARED.
313 SUM=SUM+2.*ZLIM*(WTHELI(1)*AIWWWW(1)**2+WTHELI(2)*AIWWWW(2)**2
314 $+WTHELI(3)*AIWWWW(3)**2+WTHELI(4)*AIWWWW(4)**2)
315C CROSS SECTION
316 SIG0=SUM/(32.*PI*S*SCM)*UNITS
317 SIG0=.5*SIG0
318 SIG0=SIG0*TBRWW(4,1)*TBRWW(4,2)
319 SIG=SIG0*QSAVE(27,1)*QSAVE(28,2)
320 CALL SIGFIL(SIG,27,28,29,29)
321 SIG=SIG0*QSAVE(28,1)*QSAVE(27,2)
322 CALL SIGFIL(SIG,28,27,29,29)
323C
324C Z0 Z0 --> Z0 Z0
325C
326C SET UP AMPLITUDES
327 CALL XZZZZ
328C SUM CROSS SECTION TERMS. I,J RUN OVER AMPLITUDE TERMS.
329C L RUNS OVER HELICITY STATES. N RUNS OVER POWERS.
330C REMEMBER THAT L=4 IS MISSING SIN(THETA)/SQRT(2)
331 SUM=0.
332 DO 421 I=1,4
333 DO 421 J=I,4
334 CALL SIGINT(FINT,ZLIM,ADWWWW(1,I),ADWWWW(2,I),ADWWWW(1,J),
335 $ADWWWW(2,J))
336 DO 422 L=1,4
337 TERM=0.
338 DO 423 N=0,6
339 C=0.
340 N1=MAX(N-3,0)
341 N2=MIN(3,N)
342 DO 424 K=N1,N2
343424 C=C+ANWWWW(K+1,I,L)*ANWWWW(N-K+1,J,L)
344 C=C*WTHELI(L)
345 IF(J.NE.I) C=2.*C
346 IF(L.EQ.4) THEN
347 TERM=TERM+.5*C*FINT(N+1)-.5*C*FINT(N+3)
348 ELSE
349 TERM=TERM+C*FINT(N+1)
350 ENDIF
351423 CONTINUE
352 SUM=SUM+TERM
353422 CONTINUE
354421 CONTINUE
355C ADD INTEGRAL OF IMAGINARY PART SQUARED.
356 SUM=SUM+2.*ZLIM*(WTHELI(1)*AIWWWW(1)**2+WTHELI(2)*AIWWWW(2)**2
357 $+WTHELI(3)*AIWWWW(3)**2+WTHELI(4)*AIWWWW(4)**2)
358C CROSS SECTION
359 SIG0=SUM/(32.*PI*S*SCM)*UNITS
360 SIG0=.5*SIG0
361 SIG0=SIG0*TBRWW(4,1)*TBRWW(4,2)
362 SIG=SIG0*QSAVE(29,1)*QSAVE(29,2)
363 CALL SIGFIL(SIG,29,29,29,29)
364C
365500 RETURN
366 END