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Commit | Line | Data |
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e74335a4 | 1 | * $Id$ |
2 | ||
3 | C********************************************************************* | |
4 | ||
5 | SUBROUTINE LUX4JT_HIJING(NJET,CUT,KFL,ECM,KFLN,X1,X2,X4,X12,X14) | |
6 | ||
7 | C...Purpose: to select the kinematical variables of four-jet events. | |
8 | #include "ludat1_hijing.inc" | |
9 | DIMENSION WTA(4),WTB(4),WTC(4),WTD(4),WTE(4) | |
10 | ||
11 | C...Common constants. Colour factors for QCD and Abelian gluon theory. | |
12 | PMQ=ULMASS_HIJING(KFL) | |
13 | QME=(2.*PMQ/ECM)**2 | |
14 | CT=LOG(1./CUT-5.) | |
15 | IF(MSTJ(109).EQ.0) THEN | |
16 | CF=4./3. | |
17 | CN=3. | |
18 | TR=2. | |
19 | ELSE | |
20 | CF=1. | |
21 | CN=0. | |
22 | TR=12. | |
23 | ENDIF | |
24 | ||
25 | C...Choice of process (qqbargg or qqbarqqbar). | |
26 | 100 NJET=4 | |
27 | IT=1 | |
28 | IF(PARJ(155).GT.RLU_HIJING(0)) IT=2 | |
29 | IF(MSTJ(101).LE.-3) IT=-MSTJ(101)-2 | |
30 | IF(IT.EQ.1) WTMX=0.7/CUT**2 | |
31 | IF(IT.EQ.1.AND.MSTJ(109).EQ.2) WTMX=0.6/CUT**2 | |
32 | IF(IT.EQ.2) WTMX=0.1125*CF*TR/CUT**2 | |
33 | ID=1 | |
34 | ||
35 | C...Sample the five kinematical variables (for qqgg preweighted in y34). | |
36 | 110 Y134=3.*CUT+(1.-6.*CUT)*RLU_HIJING(0) | |
37 | Y234=3.*CUT+(1.-6.*CUT)*RLU_HIJING(0) | |
38 | IF(IT.EQ.1) Y34=(1.-5.*CUT)*EXP(-CT*RLU_HIJING(0)) | |
39 | IF(IT.EQ.2) Y34=CUT+(1.-6.*CUT)*RLU_HIJING(0) | |
40 | IF(Y34.LE.Y134+Y234-1..OR.Y34.GE.Y134*Y234) GOTO 110 | |
41 | VT=RLU_HIJING(0) | |
42 | CP=COS(PARU(1)*RLU_HIJING(0)) | |
43 | Y14=(Y134-Y34)*VT | |
44 | Y13=Y134-Y14-Y34 | |
45 | VB=Y34*(1.-Y134-Y234+Y34)/((Y134-Y34)*(Y234-Y34)) | |
46 | Y24=0.5*(Y234-Y34)*(1.-4.*SQRT(MAX(0.,VT*(1.-VT)*VB*(1.-VB)))* | |
47 | &CP-(1.-2.*VT)*(1.-2.*VB)) | |
48 | Y23=Y234-Y34-Y24 | |
49 | Y12=1.-Y134-Y23-Y24 | |
50 | IF(MIN(Y12,Y13,Y14,Y23,Y24).LE.CUT) GOTO 110 | |
51 | Y123=Y12+Y13+Y23 | |
52 | Y124=Y12+Y14+Y24 | |
53 | ||
54 | C...Calculate matrix elements for qqgg or qqqq process. | |
55 | IC=0 | |
56 | WTTOT=0. | |
57 | 120 IC=IC+1 | |
58 | IF(IT.EQ.1) THEN | |
59 | WTA(IC)=(Y12*Y34**2-Y13*Y24*Y34+Y14*Y23*Y34+3.*Y12*Y23*Y34+ | |
60 | & 3.*Y12*Y14*Y34+4.*Y12**2*Y34-Y13*Y23*Y24+2.*Y12*Y23*Y24- | |
61 | & Y13*Y14*Y24-2.*Y12*Y13*Y24+2.*Y12**2*Y24+Y14*Y23**2+2.*Y12* | |
62 | & Y23**2+Y14**2*Y23+4.*Y12*Y14*Y23+4.*Y12**2*Y23+2.*Y12*Y14**2+ | |
63 | & 2.*Y12*Y13*Y14+4.*Y12**2*Y14+2.*Y12**2*Y13+2.*Y12**3)/(2.*Y13* | |
64 | & Y134*Y234*Y24)+(Y24*Y34+Y12*Y34+Y13*Y24-Y14*Y23+Y12*Y13)/(Y13* | |
65 | & Y134**2)+2.*Y23*(1.-Y13)/(Y13*Y134*Y24)+Y34/(2.*Y13*Y24) | |
66 | WTB(IC)=(Y12*Y24*Y34+Y12*Y14*Y34-Y13*Y24**2+Y13*Y14*Y24+2.*Y12* | |
67 | & Y14*Y24)/(Y13*Y134*Y23*Y14)+Y12*(1.+Y34)*Y124/(Y134*Y234*Y14* | |
68 | & Y24)-(2.*Y13*Y24+Y14**2+Y13*Y23+2.*Y12*Y13)/(Y13*Y134*Y14)+ | |
69 | & Y12*Y123*Y124/(2.*Y13*Y14*Y23*Y24) | |
70 | WTC(IC)=-(5.*Y12*Y34**2+2.*Y12*Y24*Y34+2.*Y12*Y23*Y34+2.*Y12* | |
71 | & Y14*Y34+2.*Y12*Y13*Y34+4.*Y12**2*Y34-Y13*Y24**2+Y14*Y23*Y24+ | |
72 | & Y13*Y23*Y24+Y13*Y14*Y24-Y12*Y14*Y24-Y13**2*Y24-3.*Y12*Y13*Y24- | |
73 | & Y14*Y23**2-Y14**2*Y23+Y13*Y14*Y23-3.*Y12*Y14*Y23-Y12*Y13*Y23)/ | |
74 | & (4.*Y134*Y234*Y34**2)+(3.*Y12*Y34**2-3.*Y13*Y24*Y34+3.*Y12*Y24* | |
75 | & Y34+3.*Y14*Y23*Y34-Y13*Y24**2-Y12*Y23*Y34+6.*Y12*Y14*Y34+2.*Y12* | |
76 | & Y13*Y34-2.*Y12**2*Y34+Y14*Y23*Y24-3.*Y13*Y23*Y24-2.*Y13*Y14* | |
77 | & Y24+4.*Y12*Y14*Y24+2.*Y12*Y13*Y24+3.*Y14*Y23**2+2.*Y14**2*Y23+ | |
78 | & 2.*Y14**2*Y12+2.*Y12**2*Y14+6.*Y12*Y14*Y23-2.*Y12*Y13**2- | |
79 | & 2.*Y12**2*Y13)/(4.*Y13*Y134*Y234*Y34) | |
80 | WTC(IC)=WTC(IC)+(2.*Y12*Y34**2-2.*Y13*Y24*Y34+Y12*Y24*Y34+ | |
81 | & 4.*Y13*Y23*Y34+4.*Y12*Y14*Y34+2.*Y12*Y13*Y34+2.*Y12**2*Y34- | |
82 | & Y13*Y24**2+3.*Y14*Y23*Y24+4.*Y13*Y23*Y24-2.*Y13*Y14*Y24+ | |
83 | & 4.*Y12*Y14*Y24+2.*Y12*Y13*Y24+2.*Y14*Y23**2+4.*Y13*Y23**2+ | |
84 | & 2.*Y13*Y14*Y23+2.*Y12*Y14*Y23+4.*Y12*Y13*Y23+2.*Y12*Y14**2+4.* | |
85 | & Y12**2*Y13+4.*Y12*Y13*Y14+2.*Y12**2*Y14)/(4.*Y13*Y134*Y24*Y34)- | |
86 | & (Y12*Y34**2-2.*Y14*Y24*Y34-2.*Y13*Y24*Y34-Y14*Y23*Y34+Y13*Y23* | |
87 | & Y34+Y12*Y14*Y34+2.*Y12*Y13*Y34-2.*Y14**2*Y24-4.*Y13*Y14*Y24- | |
88 | & 4.*Y13**2*Y24-Y14**2*Y23-Y13**2*Y23+Y12*Y13*Y14-Y12*Y13**2)/ | |
89 | & (2.*Y13*Y34*Y134**2)+(Y12*Y34**2-4.*Y14*Y24*Y34-2.*Y13*Y24*Y34- | |
90 | & 2.*Y14*Y23*Y34-4.*Y13*Y23*Y34-4.*Y12*Y14*Y34-4.*Y12*Y13*Y34- | |
91 | & 2.*Y13*Y14*Y24+2.*Y13**2*Y24+2.*Y14**2*Y23-2.*Y13*Y14*Y23- | |
92 | & Y12*Y14**2-6.*Y12*Y13*Y14-Y12*Y13**2)/(4.*Y34**2*Y134**2) | |
93 | WTTOT=WTTOT+Y34*CF*(CF*WTA(IC)+(CF-0.5*CN)*WTB(IC)+CN*WTC(IC))/ | |
94 | & 8. | |
95 | ELSE | |
96 | WTD(IC)=(Y13*Y23*Y34+Y12*Y23*Y34-Y12**2*Y34+Y13*Y23*Y24+2.*Y12* | |
97 | & Y23*Y24-Y14*Y23**2+Y12*Y13*Y24+Y12*Y14*Y23+Y12*Y13*Y14)/(Y13**2* | |
98 | & Y123**2)-(Y12*Y34**2-Y13*Y24*Y34+Y12*Y24*Y34-Y14*Y23*Y34-Y12* | |
99 | & Y23*Y34-Y13*Y24**2+Y14*Y23*Y24-Y13*Y23*Y24-Y13**2*Y24+Y14* | |
100 | & Y23**2)/(Y13**2*Y123*Y134)+(Y13*Y14*Y12+Y34*Y14*Y12-Y34**2*Y12+ | |
101 | & Y13*Y14*Y24+2.*Y34*Y14*Y24-Y23*Y14**2+Y34*Y13*Y24+Y34*Y23*Y14+ | |
102 | & Y34*Y13*Y23)/(Y13**2*Y134**2)-(Y34*Y12**2-Y13*Y24*Y12+Y34*Y24* | |
103 | & Y12-Y23*Y14*Y12-Y34*Y14*Y12-Y13*Y24**2+Y23*Y14*Y24-Y13*Y14*Y24- | |
104 | & Y13**2*Y24+Y23*Y14**2)/(Y13**2*Y134*Y123) | |
105 | WTE(IC)=(Y12*Y34*(Y23-Y24+Y14+Y13)+Y13*Y24**2-Y14*Y23*Y24+Y13* | |
106 | & Y23*Y24+Y13*Y14*Y24+Y13**2*Y24-Y14*Y23*(Y14+Y23+Y13))/(Y13*Y23* | |
107 | & Y123*Y134)-Y12*(Y12*Y34-Y23*Y24-Y13*Y24-Y14*Y23-Y14*Y13)/(Y13* | |
108 | & Y23*Y123**2)-(Y14+Y13)*(Y24+Y23)*Y34/(Y13*Y23*Y134*Y234)+ | |
109 | & (Y12*Y34*(Y14-Y24+Y23+Y13)+Y13*Y24**2-Y23*Y14*Y24+Y13*Y14*Y24+ | |
110 | & Y13*Y23*Y24+Y13**2*Y24-Y23*Y14*(Y14+Y23+Y13))/(Y13*Y14*Y134* | |
111 | & Y123)-Y34*(Y34*Y12-Y14*Y24-Y13*Y24-Y23*Y14-Y23*Y13)/(Y13*Y14* | |
112 | & Y134**2)-(Y23+Y13)*(Y24+Y14)*Y12/(Y13*Y14*Y123*Y124) | |
113 | WTTOT=WTTOT+CF*(TR*WTD(IC)+(CF-0.5*CN)*WTE(IC))/16. | |
114 | ENDIF | |
115 | ||
116 | C...Permutations of momenta in matrix element. Weighting. | |
117 | 130 IF(IC.EQ.1.OR.IC.EQ.3.OR.ID.EQ.2.OR.ID.EQ.3) THEN | |
118 | YSAV=Y13 | |
119 | Y13=Y14 | |
120 | Y14=YSAV | |
121 | YSAV=Y23 | |
122 | Y23=Y24 | |
123 | Y24=YSAV | |
124 | YSAV=Y123 | |
125 | Y123=Y124 | |
126 | Y124=YSAV | |
127 | ENDIF | |
128 | IF(IC.EQ.2.OR.IC.EQ.4.OR.ID.EQ.3.OR.ID.EQ.4) THEN | |
129 | YSAV=Y13 | |
130 | Y13=Y23 | |
131 | Y23=YSAV | |
132 | YSAV=Y14 | |
133 | Y14=Y24 | |
134 | Y24=YSAV | |
135 | YSAV=Y134 | |
136 | Y134=Y234 | |
137 | Y234=YSAV | |
138 | ENDIF | |
139 | IF(IC.LE.3) GOTO 120 | |
140 | IF(ID.EQ.1.AND.WTTOT.LT.RLU_HIJING(0)*WTMX) GOTO 110 | |
141 | IC=5 | |
142 | ||
143 | C...qqgg events: string configuration and event type. | |
144 | IF(IT.EQ.1) THEN | |
145 | IF(MSTJ(109).EQ.0.AND.ID.EQ.1) THEN | |
146 | PARJ(156)=Y34*(2.*(WTA(1)+WTA(2)+WTA(3)+WTA(4))+4.*(WTC(1)+ | |
147 | & WTC(2)+WTC(3)+WTC(4)))/(9.*WTTOT) | |
148 | IF(WTA(2)+WTA(4)+2.*(WTC(2)+WTC(4)).GT.RLU_HIJING(0)*(WTA(1) | |
149 | $ +WTA(2)+WTA(3)+WTA(4)+2.*(WTC(1)+WTC(2)+WTC(3)+WTC(4)))) | |
150 | $ ID=2 | |
151 | IF(ID.EQ.2) GOTO 130 | |
152 | ELSEIF(MSTJ(109).EQ.2.AND.ID.EQ.1) THEN | |
153 | PARJ(156)=Y34*(WTA(1)+WTA(2)+WTA(3)+WTA(4))/(8.*WTTOT) | |
154 | IF(WTA(2)+WTA(4).GT.RLU_HIJING(0)*(WTA(1)+WTA(2)+WTA(3)+WTA(4) | |
155 | $ )) ID=2 | |
156 | IF(ID.EQ.2) GOTO 130 | |
157 | ENDIF | |
158 | MSTJ(120)=3 | |
159 | IF(MSTJ(109).EQ.0.AND.0.5*Y34*(WTC(1)+WTC(2)+WTC(3)+WTC(4)).GT. | |
160 | & RLU_HIJING(0)*WTTOT) MSTJ(120)=4 | |
161 | KFLN=21 | |
162 | ||
163 | C...Mass cuts. Kinematical variables out. | |
164 | IF(Y12.LE.CUT+QME) NJET=2 | |
165 | IF(NJET.EQ.2) GOTO 150 | |
166 | Q12=0.5*(1.-SQRT(1.-QME/Y12)) | |
167 | X1=1.-(1.-Q12)*Y234-Q12*Y134 | |
168 | X4=1.-(1.-Q12)*Y134-Q12*Y234 | |
169 | X2=1.-Y124 | |
170 | X12=(1.-Q12)*Y13+Q12*Y23 | |
171 | X14=Y12-0.5*QME | |
172 | IF(Y134*Y234/((1.-X1)*(1.-X4)).LE.RLU_HIJING(0)) NJET=2 | |
173 | ||
174 | C...qqbarqqbar events: string configuration, choose new flavour. | |
175 | ELSE | |
176 | IF(ID.EQ.1) THEN | |
177 | WTR=RLU_HIJING(0)*(WTD(1)+WTD(2)+WTD(3)+WTD(4)) | |
178 | IF(WTR.LT.WTD(2)+WTD(3)+WTD(4)) ID=2 | |
179 | IF(WTR.LT.WTD(3)+WTD(4)) ID=3 | |
180 | IF(WTR.LT.WTD(4)) ID=4 | |
181 | IF(ID.GE.2) GOTO 130 | |
182 | ENDIF | |
183 | MSTJ(120)=5 | |
184 | PARJ(156)=CF*TR*(WTD(1)+WTD(2)+WTD(3)+WTD(4))/(16.*WTTOT) | |
185 | 140 KFLN=1+INT(5.*RLU_HIJING(0)) | |
186 | IF(KFLN.NE.KFL.AND.0.2*PARJ(156).LE.RLU_HIJING(0)) GOTO 140 | |
187 | IF(KFLN.EQ.KFL.AND.1.-0.8*PARJ(156).LE.RLU_HIJING(0)) GOTO 140 | |
188 | IF(KFLN.GT.MSTJ(104)) NJET=2 | |
189 | PMQN=ULMASS_HIJING(KFLN) | |
190 | QMEN=(2.*PMQN/ECM)**2 | |
191 | ||
192 | C...Mass cuts. Kinematical variables out. | |
193 | IF(Y24.LE.CUT+QME.OR.Y13.LE.1.1*QMEN) NJET=2 | |
194 | IF(NJET.EQ.2) GOTO 150 | |
195 | Q24=0.5*(1.-SQRT(1.-QME/Y24)) | |
196 | Q13=0.5*(1.-SQRT(1.-QMEN/Y13)) | |
197 | X1=1.-(1.-Q24)*Y123-Q24*Y134 | |
198 | X4=1.-(1.-Q24)*Y134-Q24*Y123 | |
199 | X2=1.-(1.-Q13)*Y234-Q13*Y124 | |
200 | X12=(1.-Q24)*((1.-Q13)*Y14+Q13*Y34)+Q24*((1.-Q13)*Y12+Q13*Y23) | |
201 | X14=Y24-0.5*QME | |
202 | X34=(1.-Q24)*((1.-Q13)*Y23+Q13*Y12)+Q24*((1.-Q13)*Y34+Q13*Y14) | |
203 | IF(PMQ**2+PMQN**2+MIN(X12,X34)*ECM**2.LE. | |
204 | & (PARJ(127)+PMQ+PMQN)**2) NJET=2 | |
205 | IF(Y123*Y134/((1.-X1)*(1.-X4)).LE.RLU_HIJING(0)) NJET=2 | |
206 | ENDIF | |
207 | 150 IF(MSTJ(101).LE.-2.AND.NJET.EQ.2) GOTO 100 | |
208 | ||
209 | RETURN | |
210 | END |