1 #include "isajet/pilot.h"
4 C Compute the lepton-lepton-jet cross or quark-antiquark-jet
6 C d(sigma)/d(qmw**2)d(qtw**2)d(yw)d(yj)d(omega*)
7 C for the specified W and jet types
9 C Also fix the incoming partons to be the selected types.
11 C QT cutoff from Parisi and Petronzio, Nucl Phys B154, 427
12 C qk+gl-->qk+w suppressed at low QTW
14 C Ver 6.40: Fix underflow in standard Drell-Yan
16 C Ver 7.17: include top mass for gb --> Wt and gt --> Zt
17 C with no extra qt suppression factor. Note we do NOT include
18 C gt --> Wb; while this process makes sense for qt >> m_t,
19 C it has a pole in the physical region at low qt from the
20 C on-shell decay t --> Wb. We let Q**2 --> Q**2 + m_t**2
21 C in the scale for the parton distributions.
23 C Ver 7.32: Rewrite AJLWT for gb --> Wt, etc., in terms of
24 C scaled variables, and restore SWT**5 later to avoid
25 C floating errors on VMS.
28 #if defined(CERNLIB_IMPNONE)
31 #include "isajet/itapes.inc"
32 #include "isajet/jetpar.inc"
33 #include "isajet/primar.inc"
34 #include "isajet/q1q2.inc"
35 #include "isajet/jetsig.inc"
36 #include "isajet/wsig.inc"
37 #include "isajet/qsave.inc"
38 #include "isajet/wcon.inc"
39 #include "isajet/const.inc"
41 REAL PROP,AJLWT,FCDIR,FCINT,QT2CUT,QFCN,AMASS,STRUC
42 REAL AJLZT1,AJLZT2,AJLZT3,AJLZT4
43 REAL X1WT,X2WT,P1WT,P2WT,SWT,TWT,UWT,QZW,P3Z,
44 $S,T,U,S1,T1,U1,TDIR,UDIR,TINT,UINT,COUPL,DENOM,
45 $AMT,AMT2,TERM1,TERM2,SIG0,QMW2,Q2,XX,S1WT,T1WT,U1WT,P1M,P2M,
46 $AMI2,AMF2,EFWT,A2,A2B2,AB,AL2BL2,ALBL,QQ,TM2
48 INTEGER I,JF,IFLQ,JQK,IQ1,IQ2,IFL1,IQ,IFLL,IH,IQ3
50 EQUIVALENCE (S,SHAT),(T,THAT),(U,UHAT)
51 EQUIVALENCE (S1,SHAT1),(T1,THAT1),(U1,UHAT1)
54 DATA AMFAC/11*0.,2*1./
56 C Functions. FCDIR and FCINT are direct and interference
57 C terms for virtual Compton cross section.
59 PROP(I)=1./((QMW2-WMASS(I)**2)**2+(WMASS(I)*WGAM(I))**2)
60 FCDIR(S,T,U,S1,T1,U1)=COUPL*(S*(2.*S1**2-2.*S1*U1-2.*T1*U1)
61 1+T*(-2.*S1*T1-4.*S1*U1-2.*T1*U1)+U*(2.*U1**2-2.*S1*T1-2.*S1*U1)
62 2+QMW2*(S**2+U**2+2.*T*QMW2))*(-T)/DENOM
63 FCINT(S,T,U,S1,T1,U1)=-COUPL*(S1*(S*T-T*U+T*QMW2+QMW2**2)
64 1+T1*(-S**2+U**2+2.*S*QMW2-2.*U*QMW2)+U1*(S*T-T*U-T*QMW2-QMW2**2))
67 QT2CUT(QMW)=CUTOFF*QMW**CUTPOW
68 C Parton distributions for top processes
69 QFCN(XX,IQ,IH)=STRUC(XX,QSQ+AMT2,IQ,IDIN(IH))/XX
70 C Matrix elements JL/128 from FORM
71 AJLWT(S,T,T1,U1,QQ,TM2)=
72 $ + 2*QQ**3*S*T - 2*QQ**3*S*TM2 - 2*QQ**2*S**2*TM2
73 $ - 2*QQ**2*S*T**2 + 4*QQ**2*S*T*T1 + 2*QQ**2*S*T*U1
74 $ - 4*QQ**2*S*T1*TM2 - 2*QQ**2*S*U1*TM2 + 2*QQ**2*S*TM2**2
75 $ + QQ*S**2*T*TM2 - 4*QQ*S**2*T1*TM2 + QQ*S**2*TM2**2
76 $ + QQ*S*T**3 - 2*QQ*S*T**2*T1 - QQ*S*T**2*TM2 + 2*QQ*S*T*T1**2
77 $ + 2*QQ*S*T*T1*U1 - 2*QQ*S*T*T1*TM2 + QQ*S*T*U1**2
78 $ - 3*QQ*S*T*U1*TM2 + QQ*S*T*TM2**2 - 2*QQ*S*T1**2*TM2
79 $ - 2*QQ*S*T1*U1*TM2 + 4*QQ*S*T1*TM2**2 - QQ*S*U1**2*TM2
80 $ + 3*QQ*S*U1*TM2**2 - QQ*S*TM2**3 + S**2*T*T1*TM2
81 $ - S**2*T*U1*TM2 - 2*S**2*T1**2*TM2 + S**2*T1*TM2**2
82 $ + S**2*U1*TM2**2 + S*T**2*T1*TM2 - 2*S*T*T1**2*TM2
83 $ - 2*S*T*T1*U1*TM2 - S*T*U1**2*TM2 + S*T*U1*TM2**2
84 $ + 2*S*T1**2*TM2**2 + 2*S*T1*U1*TM2**2 - S*T1*TM2**3
85 $ + S*U1**2*TM2**2 - S*U1*TM2**3
87 AJLZT1(S,T,T1,U1,QQ,TM2)=
88 $ + A2*AL2BL2 * ( 8*QQ**2*S*T*TM2 - 8*QQ**2*S*TM2**2
89 $ - 8*QQ**2*T*TM2**2 + 8*QQ**2*TM2**3 - 8*QQ*S**2*T*TM2
90 $ - 8*QQ*S*T**2*TM2 + 16*QQ*S*T*TM2**2 + 8*QQ*S*TM2**3
91 $ + 8*QQ*T*TM2**3 - 16*QQ*TM2**4 + 8*S**2*T*U1*TM2
92 $ - 8*S**2*U1*TM2**2 + 8*S*T**2*U1*TM2 + 8*S*T*U1**2*TM2
93 $ - 32*S*T*U1*TM2**2 - 8*S*U1**2*TM2**2 + 24*S*U1*TM2**3
94 $ - 8*T**2*U1*TM2**2 - 8*T*U1**2*TM2**2 + 24*T*U1*TM2**3
95 $ + 8*U1**2*TM2**3 - 16*U1*TM2**4 )/8.
96 AJLZT2(S,T,T1,U1,QQ,TM2)=
97 $ + A2B2*AL2BL2 * ( 2*QQ**3*S*T - 2*QQ**3*S*TM2
98 $ - 2*QQ**3*T*TM2 + 2*QQ**3*TM2**2 - 2*QQ**2*S**2*TM2
99 $ - 2*QQ**2*S*T**2 + 4*QQ**2*S*T*T1 + 2*QQ**2*S*T*U1
100 $ - 8*QQ**2*S*T*TM2 - 4*QQ**2*S*T1*TM2 - 2*QQ**2*S*U1*TM2
101 $ + 14*QQ**2*S*TM2**2 - 4*QQ**2*T*T1*TM2 - 2*QQ**2*T*U1*TM2
102 $ + 12*QQ**2*T*TM2**2 + 4*QQ**2*T1*TM2**2 + 2*QQ**2*U1*TM2**2
103 $ - 14*QQ**2*TM2**3 + QQ*S**3*T - QQ*S**3*TM2 + 2*QQ*S**2*T*T1
104 $ + 2*QQ*S**2*T*U1 - QQ*S**2*T*TM2 - 6*QQ*S**2*T1*TM2
105 $ - 2*QQ*S**2*U1*TM2 + 9*QQ*S**2*TM2**2 + QQ*S*T**3
106 $ - 2*QQ*S*T**2*T1 + 3*QQ*S*T**2*TM2 + 4*QQ*S*T*T1**2
107 $ + 4*QQ*S*T*T1*U1 - 16*QQ*S*T*T1*TM2 + 2*QQ*S*T*U1**2
108 $ - 12*QQ*S*T*U1*TM2 + 10*QQ*S*T*TM2**2 - 4*QQ*S*T1**2*TM2
109 $ - 4*QQ*S*T1*U1*TM2 + 26*QQ*S*T1*TM2**2 - 2*QQ*S*U1**2*TM2
110 $ + 12*QQ*S*U1*TM2**2 - 30*QQ*S*TM2**3 - QQ*T**3*TM2
111 $ - 2*QQ*T**2*T1*TM2 - 4*QQ*T**2*U1*TM2 + 5*QQ*T**2*TM2**2
112 $ - 4*QQ*T*T1**2*TM2 - 4*QQ*T*T1*U1*TM2 + 22*QQ*T*T1*TM2**2
113 $ - 2*QQ*T*U1**2*TM2 + 18*QQ*T*U1*TM2**2 )/8.
114 AJLZT3(S,T,T1,U1,QQ,TM2)=
115 $ + A2B2*AL2BL2 * ( - 26*QQ*T*TM2**3 + 4*QQ*T1**2*TM2**2
116 $ + 4*QQ*T1*U1*TM2**2 - 24*QQ*T1*TM2**3 + 2*QQ*U1**2*TM2**2
117 $ - 14*QQ*U1*TM2**3 + 30*QQ*TM2**4 - 8*S**2*T*U1*TM2
118 $ - 4*S**2*T1**2*TM2 + 8*S**2*T1*TM2**2 + 8*S**2*U1*TM2**2
119 $ - 4*S**2*TM2**3 - 8*S*T**2*U1*TM2 - 8*S*T*T1**2*TM2
120 $ - 8*S*T*T1*U1*TM2 + 16*S*T*T1*TM2**2 - 8*S*T*U1**2*TM2
121 $ + 40*S*T*U1*TM2**2 - 8*S*T*TM2**3 + 16*S*T1**2*TM2**2
122 $ + 8*S*T1*U1*TM2**2 - 32*S*T1*TM2**3 + 8*S*U1**2*TM2**2
123 $ - 32*S*U1*TM2**3 + 16*S*TM2**4 - 4*T**2*T1**2*TM2
124 $ - 8*T**2*T1*U1*TM2 + 8*T**2*T1*TM2**2 - 4*T**2*U1**2*TM2
125 $ + 16*T**2*U1*TM2**2 - 4*T**2*TM2**3 + 16*T*T1**2*TM2**2
126 $ + 24*T*T1*U1*TM2**2 - 32*T*T1*TM2**3 + 16*T*U1**2*TM2**2
127 $ - 48*T*U1*TM2**3 + 16*T*TM2**4 - 16*T1**2*TM2**3
128 $ - 16*T1*U1*TM2**3 + 32*T1*TM2**4 - 12*U1**2*TM2**3
129 $ + 32*U1*TM2**4 - 16*TM2**5 )/8.
130 AJLZT4(S,T,T1,U1,QQ,TM2)=
131 $ + AB*ALBL * ( 8*QQ**3*S*T - 8*QQ**3*S*TM2 - 8*QQ**3*T*TM2
132 $ + 8*QQ**3*TM2**2 - 8*QQ**2*S**2*TM2 - 8*QQ**2*S*T**2
133 $ + 16*QQ**2*S*T*T1 + 8*QQ**2*S*T*U1 - 16*QQ**2*S*T*TM2
134 $ - 16*QQ**2*S*T1*TM2 - 8*QQ**2*S*U1*TM2 + 40*QQ**2*S*TM2**2
135 $ - 16*QQ**2*T*T1*TM2 - 8*QQ**2*T*U1*TM2 + 32*QQ**2*T*TM2**2
136 $ + 16*QQ**2*T1*TM2**2 + 8*QQ**2*U1*TM2**2 - 40*QQ**2*TM2**3
137 $ - 4*QQ*S**3*T + 4*QQ*S**3*TM2 - 8*QQ*S**2*T*T1
138 $ - 8*QQ*S**2*T*U1 + 20*QQ*S**2*T*TM2 - 8*QQ*S**2*T1*TM2
139 $ + 8*QQ*S**2*U1*TM2 - 4*QQ*S**2*TM2**2 + 4*QQ*S*T**3
140 $ - 8*QQ*S*T**2*T1 - 4*QQ*S*T**2*TM2 + 40*QQ*S*T1*TM2**2
141 $ - 32*QQ*S*TM2**3 - 4*QQ*T**3*TM2 - 8*QQ*T**2*T1*TM2
142 $ - 16*QQ*T**2*U1*TM2 + 20*QQ*T**2*TM2**2 + 40*QQ*T*T1*TM2**2
143 $ + 40*QQ*T*U1*TM2**2 - 48*QQ*T*TM2**3 - 48*QQ*T1*TM2**3
144 $ - 24*QQ*U1*TM2**3 + 48*QQ*TM2**4 )/8.
146 C Find whether JETTYP(1) or JETTYP(2) is particle
149 IF(2*(JETTYP(1)/2).NE.JETTYP(1)) JF=2
156 QW=SQRT(QZW**2+QTW**2)
158 T1=-X2*ECM*PT(JF)*EXP(YJ(JF))
159 U1=-X1*ECM*PT(JF)*EXP(-YJ(JF))
166 IF(JETTYP(3).EQ.1) THEN
168 COUPL=-ALFA**2*ALFQSQ*PROP(JWTYP)/(9.*PI*SCM*S)
169 DENOM=S**2*EXP(.5*ALOG(QTW**4+QT2CUT(QMW)**2))
170 TDIR=FCDIR(T,S,U,T1,S1,U1)*(AQ(IFLL,JWTYP)**2+BQ(IFLL,JWTYP)**2)
171 UDIR=FCDIR(U,S,T,U1,S1,T1)*(AQ(IFLL,JWTYP)**2+BQ(IFLL,JWTYP)**2)
172 TINT=FCINT(T,S,U,T1,S1,U1)*2.*AQ(IFLL,JWTYP)*BQ(IFLL,JWTYP)
173 UINT=FCINT(U,S,T,U1,S1,T1)*2.*AQ(IFLL,JWTYP)*BQ(IFLL,JWTYP)
177 IF(2*IFL1.EQ.IQ1) THEN
178 TERM1=TDIR*(AQ(IFL1,JWTYP)**2+BQ(IFL1,JWTYP)**2)
179 $ *QSAVE(IQ1,1)*QSAVE(IQ2,2)
180 TERM2=TINT*2.*AQ(IFL1,JWTYP)*BQ(IFL1,JWTYP)
181 $ *QSAVE(IQ1,1)*QSAVE(IQ2,2)
182 SIGLLQ=SIGLLQ+TERM1+TERM2
184 TERM1=UDIR*(AQ(IFL1,JWTYP)**2+BQ(IFL1,JWTYP)**2)
185 $ *QSAVE(IQ1,1)*QSAVE(IQ2,2)
186 TERM2=UINT*2.*AQ(IFL1,JWTYP)*BQ(IFL1,JWTYP)
187 $ *QSAVE(IQ1,1)*QSAVE(IQ2,2)
188 SIGLLQ=SIGLLQ+TERM1+TERM2
191 IF(JETTYP(1).LE.13) SIGLLQ=3.*SIGLLQ
196 ELSEIF(JETTYP(3).LE.NZERO(JWTYP)) THEN
197 JQK=MATCH(JETTYP(3),4)
200 COUPL=ALFA**2*ALFQSQ*PROP(JWTYP)/(24.*PI*SCM*S)
201 DENOM=S**2*EXP(.5*ALOG(QTW**4+QT2CUT(QMW)**2))
204 IF(INITYP(2).EQ.1) THEN
205 TDIR=FCDIR(S,T,U,S1,T1,U1)*QSAVE(JQK,1)*QSAVE(1,2)
207 TDIR=FCDIR(S,U,T,S1,U1,T1)*QSAVE(JQK,2)*QSAVE(1,1)
209 TDIR=TDIR*(AQ(IFLQ,JWTYP)**2+BQ(IFLQ,JWTYP)**2)
210 $ *(AQ(IFLL,JWTYP)**2+BQ(IFLL,JWTYP)**2)
211 IF(INITYP(2).EQ.1) THEN
212 TINT=FCINT(S,T,U,S1,T1,U1)*QSAVE(JQK,1)*QSAVE(1,2)
214 TINT=FCINT(S,U,T,S1,U1,T1)*QSAVE(JQK,2)*QSAVE(1,1)
216 TINT=TINT*4.*AQ(IFLQ,JWTYP)*BQ(IFLQ,JWTYP)*AQ(IFLL,JWTYP)
220 IF(JETTYP(1).LE.13) SIGLLQ=3.*SIGLLQ
221 SIGLLQ=SIGLLQ*QTW**2/(QTW**2+QT2CUT(QMW))
224 C bt,tp + gl --> bt,tp + W,Z
226 ELSEIF(JETTYP(3).GE.NZERO(JWTYP)+1) THEN
236 EFWT=SQRT(P(3)**2+AMF2)
238 SWT=QMW2+AMF2+2.*Q0W*EFWT-2.*QZW*P3Z+2.*PT(3)**2
240 IF(INITYP(2).EQ.1) THEN
241 P1WT=EFWT+P3Z+Q0W+QZW
243 P2WT=EFWT-P3Z+Q0W-QZW-P1M
246 TWT=-P1WT*(EFWT-P3Z)-P1M*(P(3)+P3Z)+AMI2+AMF2
247 UWT=-P2WT*(EFWT+P3Z)+AMF2
248 T1WT=-X2WT*ECM*PT(JF)*EXP(YJ(JF))
249 U1WT=-X1WT*ECM*PT(JF)*EXP(-YJ(JF))-P1M*PT(JF)*EXP(YJ(JF))
250 S1WT=-T1WT-U1WT-QMW2+AMI2+AMF2
252 P2WT=EFWT-P3Z+Q0W-QZW
254 P1WT=EFWT+P3Z+Q0W+QZW-P2M
257 TWT=-P1WT*(EFWT-P3Z)+AMF2
258 UWT=-P2WT*(EFWT+P3Z)-P2M*(EFWT-P3Z)+AMI2+AMF2
259 T1WT=-X2WT*ECM*PT(JF)*EXP(YJ(JF))-P2M*PT(JF)*EXP(-YJ(JF))
260 U1WT=-X1WT*ECM*PT(JF)*EXP(-YJ(JF))
261 S1WT=-T1WT-U1WT-QMW2+AMI2+AMF2
264 SIG0=-ALFA**2*ALFQSQ/(12*PI*SCM*SWT)*PROP(JWTYP)*UNITS
265 IF(JETTYP(1).LE.13) SIG0=3*SIG0
266 IF(JWTYP.EQ.2.OR.JWTYP.EQ.3) THEN
267 SIG0=SIG0*(AQ(6,JWTYP)**2+BQ(6,JWTYP)**2)**2
268 IF(INITYP(2).EQ.1.AND.(IQ3.EQ.12.OR.IQ3.EQ.13)) THEN
269 SIGLLQ=AJLWT(SWT/SWT,TWT/SWT,T1WT/SWT,U1WT/SWT,Q2/SWT,
271 SIGLLQ=SIGLLQ*SWT*(SWT/(SWT-AMI2))**2*(SWT/(TWT-AMF2))**2
272 SIGLLQ=SIGLLQ*SIG0*QFCN(X1WT,JQK,1)*QFCN(X2WT,1,2)
273 ELSEIF(INITYP(1).EQ.1.AND.(IQ3.EQ.12.OR.IQ3.EQ.13)) THEN
274 SIGLLQ=AJLWT(SWT/SWT,UWT/SWT,U1WT/SWT,T1WT/SWT,Q2/SWT,
276 SIGLLQ=SIGLLQ*SWT*(SWT/(SWT-AMI2))**2*(SWT/(TWT-AMF2))**2
277 SIGLLQ=SIGLLQ*SIG0*QFCN(X1WT,JQK,2)*QFCN(X2WT,1,1)
279 ELSEIF(JWTYP.EQ.4) THEN
281 A2B2=AQ(6,JWTYP)**2+BQ(6,JWTYP)**2
282 AB=AQ(6,JWTYP)*BQ(6,JWTYP)
283 AL2BL2=AQ(JETTYP(1)/2,JWTYP)**2+BQ(JETTYP(1)/2,JWTYP)**2
284 ALBL=AQ(JETTYP(1)/2,JWTYP)*BQ(JETTYP(1)/2,JWTYP)
285 IF(INITYP(2).EQ.1) THEN
286 SIGLLQ=AJLZT1(SWT/SWT,TWT/SWT,T1WT/SWT,U1WT/SWT,
288 SIGLLQ=SIGLLQ+AJLZT2(SWT/SWT,TWT/SWT,T1WT/SWT,U1WT/SWT,
290 SIGLLQ=SIGLLQ+AJLZT3(SWT/SWT,TWT/SWT,T1WT/SWT,U1WT/SWT,
292 SIGLLQ=SIGLLQ+AJLZT4(SWT/SWT,TWT/SWT,T1WT/SWT,U1WT/SWT,
294 SIGLLQ=SIGLLQ*SWT*(SWT/(SWT-AMI2))**2*(SWT/(TWT-AMF2))**2
295 SIGLLQ=SIGLLQ*SIG0*QFCN(X1WT,JQK,1)*QFCN(X2WT,1,2)
296 ELSEIF(INITYP(1).EQ.1) THEN
297 SIGLLQ=AJLZT1(SWT/SWT,UWT/SWT,U1WT/SWT,T1WT/SWT,
299 SIGLLQ=SIGLLQ+AJLZT2(SWT/SWT,UWT/SWT,U1WT/SWT,T1WT/SWT,
301 SIGLLQ=SIGLLQ+AJLZT3(SWT/SWT,UWT/SWT,U1WT/SWT,T1WT/SWT,
303 SIGLLQ=SIGLLQ+AJLZT4(SWT/SWT,UWT/SWT,U1WT/SWT,T1WT/SWT,
305 SIGLLQ=SIGLLQ*SWT*(SWT/(SWT-AMI2))**2*(SWT/(UWT-AMF2))**2
306 SIGLLQ=SIGLLQ*SIG0*QFCN(X1WT,JQK,2)*QFCN(X2WT,1,1)
312 C Standard Drell-Yan with QT=0.
316 COUPL=ALFA**2*PROP(JWTYP)*UNITS
317 TDIR=COUPL*(AQ(IFLL,JWTYP)**2+BQ(IFLL,JWTYP)**2)
318 $*((U1**2+T1**2)/(6.*SCM*QMW2))
319 TINT=COUPL*2.*AQ(IFLL,JWTYP)*BQ(IFLL,JWTYP)
320 $*((U1**2-T1**2)/(6.*SCM*QMW2))
324 TERM1=TDIR*(AQ(IFL1,JWTYP)**2+BQ(IFL1,JWTYP)**2)
325 $*QSAVE(IQ1,1)*QSAVE(IQ2,2)
326 TERM2=-TINT*2.*AQ(IFL1,JWTYP)*BQ(IFL1,JWTYP)
327 $*QSAVE(IQ1,1)*QSAVE(IQ2,2)
328 IF(2*IFL1.EQ.IQ1) SIGLLQ=SIGLLQ+TERM1+TERM2
329 IF(2*IFL1.NE.IQ1) SIGLLQ=SIGLLQ+TERM1-TERM2
330 IF(JETTYP(1).LE.13) SIGLLQ=3.*SIGLLQ