hijing/src/crsjet.f

0001 C
0002 C
0003 C       THIS PROGRAM IS TO CALCULATE THE JET CROSS SECTION
0004 C       THE INTEGRATION IS DONE BY USING VEGAS
0005 C
0006         SUBROUTINE CRSJET
0007         IMPLICIT REAL*8(A-H,O-Z)
0008         REAL HIPR1(100),HINT1(100)
0009         COMMON/HIPARNT/HIPR1,IHPR2(50),HINT1,IHNT2(50)
0010         SAVE  /HIPARNT/
0011         COMMON/NJET/N,IP_CRS
0012         SAVE  /NJET/
0013         COMMON/BVEG1/XL(10),XU(10),ACC,NDIM,NCALL,ITMX,NPRN
0014         SAVE  /BVEG1/
0015         COMMON/BVEG2/XI(50,10),SI,SI2,SWGT,SCHI,NDO,IT
0016         SAVE  /BVEG2/
0017         COMMON/BVEG3/F,TI,TSI
0018         SAVE  /BVEG3/
0019         COMMON/SEEDVAX/NUM1
0020         SAVE  /SEEDVAX/
0021         EXTERNAL FJET,FJETRIG
0022 C
0023 c************************
0024 c       NCALL give the number of inner-iteration, ITMX
0025 C       gives the limit of out-iteration. Nprn is an option
0026 C       ( 1: print the integration process. 0: do not print)
0027 C
0028
0029 C       print *, 'ncall = ', ncall
0030 C       print *, 'itmx = ', itmx
0031 C       print *, 'nprn = ', nprn
0032 C       print *, 'acc = ', acc
0033 C       print *, 'xl(1), xu(1) = ', XL(1), XU(1)
0034 C       print *, 'xl(2), xu(2) = ', XL(2), XU(2)
0035 C       print *, 'xl(3), xu(3) = ', XL(3), XU(3)
0036
0037 C +++BAC
0038 C
0039 C  The following line inserted to improve the accuracy of the jet cross-section
0040 C    integration for LHC purposes where integration region runs out to XT=1 where the
0041 C    contribution is infinitesimal. Found to be necessary because large jet cross-section
0042 C    errors were affecting total and inelastic cross-sections.
0043 C
0044         ncall = 4000
0045
0046 C ---BAC
0047
0048         NDIM=3
0049         IP_CRS=0
0050         CALL VEGAS(FJET,AVGI,SD,CHI2A)
0051         HINT1(14)=AVGI/2.5682
0052         IF(IHPR2(6).EQ.1 .AND. IHNT2(1).GT.1) THEN
0053                 IP_CRS=1
0054                 CALL VEGAS(FJET,AVGI,SD,CHI2A)
0055                 HINT1(15)=AVGI/2.5682
0056         ENDIF
0057         IF(IHPR2(6).EQ.1 .AND. IHNT2(3).GT.1) THEN
0058                 IP_CRS=2
0059                 CALL VEGAS(FJET,AVGI,SD,CHI2A)
0060                 HINT1(16)=AVGI/2.5682
0061         ENDIF
0062         IF(IHPR2(6).EQ.1.AND.IHNT2(1).GT.1.AND.IHNT2(3).GT.1) THEN
0063                 IP_CRS=3
0064                 CALL VEGAS(FJET,AVGI,SD,CHI2A)
0065                 HINT1(17)=AVGI/2.5682
0066         ENDIF
0067 C               ********Total inclusive jet cross section(Pt>P0)
0068 C
0069         IF(IHPR2(3).NE.0) THEN
0070            IP_CRS=0
0071            CALL VEGAS(FJETRIG,AVGI,SD,CHI2A)
0072            HINT1(61)=AVGI/2.5682
0073            IF(IHPR2(6).EQ.1 .AND. IHNT2(1).GT.1) THEN
0074               IP_CRS=1
0075               CALL VEGAS(FJETRIG,AVGI,SD,CHI2A)
0076               HINT1(62)=AVGI/2.5682
0077            ENDIF
0078            IF(IHPR2(6).EQ.1 .AND. IHNT2(3).GT.1) THEN
0079               IP_CRS=2
0080               CALL VEGAS(FJETRIG,AVGI,SD,CHI2A)
0081               HINT1(63)=AVGI/2.5682
0082            ENDIF
0083            IF(IHPR2(6).EQ.1.AND.IHNT2(1).GT.1.AND.IHNT2(3).GT.1) THEN
0084               IP_CRS=3
0085               CALL VEGAS(FJETRIG,AVGI,SD,CHI2A)
0086               HINT1(64)=AVGI/2.5682
0087            ENDIF
0088         ENDIF
0089 C                       ********cross section of trigger jet
0090 C
0091         RETURN
0092         END