| fe4da5cc |
1 | |
| 2 | C********************************************************************* |
| 3 | |
| 4 | SUBROUTINE LUXTOT(KFL,ECM,XTOT) |
| 5 | |
| 6 | C...Purpose: to calculate total cross-section, including initial |
| 7 | C...state radiation effects. |
| 8 | COMMON/LUDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200) |
| 9 | COMMON/LUDAT2/KCHG(500,3),PMAS(500,4),PARF(2000),VCKM(4,4) |
| 10 | SAVE /LUDAT1/,/LUDAT2/ |
| 11 | |
| 12 | C...Status, (optimized) Q^2 scale, alpha_strong. |
| 13 | PARJ(151)=ECM |
| 14 | MSTJ(119)=10*MSTJ(102)+KFL |
| 15 | IF(MSTJ(111).EQ.0) THEN |
| 16 | Q2R=ECM**2 |
| 17 | ELSEIF(MSTU(111).EQ.0) THEN |
| 18 | PARJ(168)=MIN(1.,MAX(PARJ(128),EXP(-12.*PARU(1)/ |
| 19 | & ((33.-2.*MSTU(112))*PARU(111))))) |
| 20 | Q2R=PARJ(168)*ECM**2 |
| 21 | ELSE |
| 22 | PARJ(168)=MIN(1.,MAX(PARJ(128),PARU(112)/ECM, |
| 23 | & (2.*PARU(112)/ECM)**2)) |
| 24 | Q2R=PARJ(168)*ECM**2 |
| 25 | ENDIF |
| 26 | ALSPI=ULALPS(Q2R)/PARU(1) |
| 27 | |
| 28 | C...QCD corrections factor in R. |
| 29 | IF(MSTJ(101).EQ.0.OR.MSTJ(109).EQ.1) THEN |
| 30 | RQCD=1. |
| 31 | ELSEIF(IABS(MSTJ(101)).EQ.1.AND.MSTJ(109).EQ.0) THEN |
| 32 | RQCD=1.+ALSPI |
| 33 | ELSEIF(MSTJ(109).EQ.0) THEN |
| 34 | RQCD=1.+ALSPI+(1.986-0.115*MSTU(118))*ALSPI**2 |
| 35 | IF(MSTJ(111).EQ.1) RQCD=MAX(1.,RQCD+(33.-2.*MSTU(112))/12.* |
| 36 | & LOG(PARJ(168))*ALSPI**2) |
| 37 | ELSEIF(IABS(MSTJ(101)).EQ.1) THEN |
| 38 | RQCD=1.+(3./4.)*ALSPI |
| 39 | ELSE |
| 40 | RQCD=1.+(3./4.)*ALSPI-(3./32.+0.519*MSTU(118))*ALSPI**2 |
| 41 | ENDIF |
| 42 | |
| 43 | C...Calculate Z0 width if default value not acceptable. |
| 44 | IF(MSTJ(102).GE.3) THEN |
| 45 | RVA=3.*(3.+(4.*PARU(102)-1.)**2)+6.*RQCD*(2.+(1.-8.*PARU(102)/ |
| 46 | & 3.)**2+(4.*PARU(102)/3.-1.)**2) |
| 47 | DO 100 KFLC=5,6 |
| 48 | VQ=1. |
| 49 | IF(MOD(MSTJ(103),2).EQ.1) VQ=SQRT(MAX(0.,1.-(2.*ULMASS(KFLC)/ |
| 50 | & ECM)**2)) |
| 51 | IF(KFLC.EQ.5) VF=4.*PARU(102)/3.-1. |
| 52 | IF(KFLC.EQ.6) VF=1.-8.*PARU(102)/3. |
| 53 | RVA=RVA+3.*RQCD*(0.5*VQ*(3.-VQ**2)*VF**2+VQ**3) |
| 54 | 100 CONTINUE |
| 55 | PARJ(124)=PARU(101)*PARJ(123)*RVA/(48.*PARU(102)*(1.-PARU(102))) |
| 56 | ENDIF |
| 57 | |
| 58 | C...Calculate propagator and related constants for QFD case. |
| 59 | POLL=1.-PARJ(131)*PARJ(132) |
| 60 | IF(MSTJ(102).GE.2) THEN |
| 61 | SFF=1./(16.*PARU(102)*(1.-PARU(102))) |
| 62 | SFW=ECM**4/((ECM**2-PARJ(123)**2)**2+(PARJ(123)*PARJ(124))**2) |
| 63 | SFI=SFW*(1.-(PARJ(123)/ECM)**2) |
| 64 | VE=4.*PARU(102)-1. |
| 65 | SF1I=SFF*(VE*POLL+PARJ(132)-PARJ(131)) |
| 66 | SF1W=SFF**2*((VE**2+1.)*POLL+2.*VE*(PARJ(132)-PARJ(131))) |
| 67 | HF1I=SFI*SF1I |
| 68 | HF1W=SFW*SF1W |
| 69 | ENDIF |
| 70 | |
| 71 | C...Loop over different flavours: charge, velocity. |
| 72 | RTOT=0. |
| 73 | RQQ=0. |
| 74 | RQV=0. |
| 75 | RVA=0. |
| 76 | DO 110 KFLC=1,MAX(MSTJ(104),KFL) |
| 77 | IF(KFL.GT.0.AND.KFLC.NE.KFL) GOTO 110 |
| 78 | MSTJ(93)=1 |
| 79 | PMQ=ULMASS(KFLC) |
| 80 | IF(ECM.LT.2.*PMQ+PARJ(127)) GOTO 110 |
| 81 | QF=KCHG(KFLC,1)/3. |
| 82 | VQ=1. |
| 83 | IF(MOD(MSTJ(103),2).EQ.1) VQ=SQRT(1.-(2.*PMQ/ECM)**2) |
| 84 | |
| 85 | C...Calculate R and sum of charges for QED or QFD case. |
| 86 | RQQ=RQQ+3.*QF**2*POLL |
| 87 | IF(MSTJ(102).LE.1) THEN |
| 88 | RTOT=RTOT+3.*0.5*VQ*(3.-VQ**2)*QF**2*POLL |
| 89 | ELSE |
| 90 | VF=SIGN(1.,QF)-4.*QF*PARU(102) |
| 91 | RQV=RQV-6.*QF*VF*SF1I |
| 92 | RVA=RVA+3.*(VF**2+1.)*SF1W |
| 93 | RTOT=RTOT+3.*(0.5*VQ*(3.-VQ**2)*(QF**2*POLL-2.*QF*VF*HF1I+ |
| 94 | & VF**2*HF1W)+VQ**3*HF1W) |
| 95 | ENDIF |
| 96 | 110 CONTINUE |
| 97 | RSUM=RQQ |
| 98 | IF(MSTJ(102).GE.2) RSUM=RQQ+SFI*RQV+SFW*RVA |
| 99 | |
| 100 | C...Calculate cross-section, including QCD corrections. |
| 101 | PARJ(141)=RQQ |
| 102 | PARJ(142)=RTOT |
| 103 | PARJ(143)=RTOT*RQCD |
| 104 | PARJ(144)=PARJ(143) |
| 105 | PARJ(145)=PARJ(141)*86.8/ECM**2 |
| 106 | PARJ(146)=PARJ(142)*86.8/ECM**2 |
| 107 | PARJ(147)=PARJ(143)*86.8/ECM**2 |
| 108 | PARJ(148)=PARJ(147) |
| 109 | PARJ(157)=RSUM*RQCD |
| 110 | PARJ(158)=0. |
| 111 | PARJ(159)=0. |
| 112 | XTOT=PARJ(147) |
| 113 | IF(MSTJ(107).LE.0) RETURN |
| 114 | |
| 115 | C...Virtual cross-section. |
| 116 | XKL=PARJ(135) |
| 117 | XKU=MIN(PARJ(136),1.-(2.*PARJ(127)/ECM)**2) |
| 118 | ALE=2.*LOG(ECM/ULMASS(11))-1. |
| 119 | SIGV=ALE/3.+2.*LOG(ECM**2/(ULMASS(13)*ULMASS(15)))/3.-4./3.+ |
| 120 | &1.526*LOG(ECM**2/0.932) |
| 121 | |
| 122 | C...Soft and hard radiative cross-section in QED case. |
| 123 | IF(MSTJ(102).LE.1) THEN |
| 124 | SIGV=1.5*ALE-0.5+PARU(1)**2/3.+2.*SIGV |
| 125 | SIGS=ALE*(2.*LOG(XKL)-LOG(1.-XKL)-XKL) |
| 126 | SIGH=ALE*(2.*LOG(XKU/XKL)-LOG((1.-XKU)/(1.-XKL))-(XKU-XKL)) |
| 127 | |
| 128 | C...Soft and hard radiative cross-section in QFD case. |
| 129 | ELSE |
| 130 | SZM=1.-(PARJ(123)/ECM)**2 |
| 131 | SZW=PARJ(123)*PARJ(124)/ECM**2 |
| 132 | PARJ(161)=-RQQ/RSUM |
| 133 | PARJ(162)=-(RQQ+RQV+RVA)/RSUM |
| 134 | PARJ(163)=(RQV*(1.-0.5*SZM-SFI)+RVA*(1.5-SZM-SFW))/RSUM |
| 135 | PARJ(164)=(RQV*SZW**2*(1.-2.*SFW)+RVA*(2.*SFI+SZW**2-4.+3.*SZM- |
| 136 | & SZM**2))/(SZW*RSUM) |
| 137 | SIGV=1.5*ALE-0.5+PARU(1)**2/3.+((2.*RQQ+SFI*RQV)/RSUM)*SIGV+ |
| 138 | & (SZW*SFW*RQV/RSUM)*PARU(1)*20./9. |
| 139 | SIGS=ALE*(2.*LOG(XKL)+PARJ(161)*LOG(1.-XKL)+PARJ(162)*XKL+ |
| 140 | & PARJ(163)*LOG(((XKL-SZM)**2+SZW**2)/(SZM**2+SZW**2))+ |
| 141 | & PARJ(164)*(ATAN((XKL-SZM)/SZW)-ATAN(-SZM/SZW))) |
| 142 | SIGH=ALE*(2.*LOG(XKU/XKL)+PARJ(161)*LOG((1.-XKU)/(1.-XKL))+ |
| 143 | & PARJ(162)*(XKU-XKL)+PARJ(163)*LOG(((XKU-SZM)**2+SZW**2)/ |
| 144 | & ((XKL-SZM)**2+SZW**2))+PARJ(164)*(ATAN((XKU-SZM)/SZW)- |
| 145 | & ATAN((XKL-SZM)/SZW))) |
| 146 | ENDIF |
| 147 | |
| 148 | C...Total cross-section and fraction of hard photon events. |
| 149 | PARJ(160)=SIGH/(PARU(1)/PARU(101)+SIGV+SIGS+SIGH) |
| 150 | PARJ(157)=RSUM*(1.+(PARU(101)/PARU(1))*(SIGV+SIGS+SIGH))*RQCD |
| 151 | PARJ(144)=PARJ(157) |
| 152 | PARJ(148)=PARJ(144)*86.8/ECM**2 |
| 153 | XTOT=PARJ(148) |
| 154 | |
| 155 | RETURN |
| 156 | END |
git://git.uio.no / u / mrichter / AliRoot.git / blame