HIJING/hipyset1_35/pyxtot_hijing.F

   1 * $Id$
   2
   3 C*********************************************************************
   4
   5       SUBROUTINE PYXTOT_HIJING
   6
   7 C...Parametrizes total, double diffractive, single diffractive and
   8 C...elastic cross-sections for different energies and beams.
   9 #include "ludat1_hijing.inc"
  10 #include "pypars_hijing.inc"
  11 #include "pyint1_hijing.inc"
  12 #include "pyint5_hijing.inc"
  13       DIMENSION BCS(5,8),BCB(2,5),BCC(3)
  14
  15 C...The following data lines are coefficients needed in the
  16 C...Block, Cahn parametrization of total cross-section and nuclear
  17 C...slope parameter; see below.
  18       DATA ((BCS(I,J),J=1,8),I=1,5)/
  19      1 41.74, 0.66, 0.0000, 337.,  0.0, 0.0, -39.3, 0.48,
  20      2 41.66, 0.60, 0.0000, 306.,  0.0, 0.0, -34.6, 0.51,
  21      3 41.36, 0.63, 0.0000, 299.,  7.3, 0.5, -40.4, 0.47,
  22      4 41.68, 0.63, 0.0083, 330.,  0.0, 0.0, -39.0, 0.48,
  23      5 41.13, 0.59, 0.0074, 278., 10.5, 0.5, -41.2, 0.46/
  24       DATA ((BCB(I,J),J=1,5),I=1,2)/
  25      1 10.79, -0.049, 0.040, 21.5, 1.23,
  26      2  9.92, -0.027, 0.013, 18.9, 1.07/
  27       DATA BCC/2.0164346,-0.5590311,0.0376279/
  28
  29 C...Total cross-section and nuclear slope parameter for pp and p-pbar
  30       NFIT=MIN(5,MAX(1,MSTP(31)))
  31       SIGP=BCS(NFIT,1)+BCS(NFIT,2)*(-0.25*PARU(1)**2*
  32      &(1.-0.25*BCS(NFIT,3)*PARU(1)**2)+(1.+0.5*BCS(NFIT,3)*PARU(1)**2)*
  33      &(LOG(VINT(2)/BCS(NFIT,4)))**2+BCS(NFIT,3)*
  34      &(LOG(VINT(2)/BCS(NFIT,4)))**4)/
  35      &((1.-0.25*BCS(NFIT,3)*PARU(1)**2)**2+2.*BCS(NFIT,3)*
  36      &(1.+0.25*BCS(NFIT,3)*PARU(1)**2)*(LOG(VINT(2)/BCS(NFIT,4)))**2+
  37      &BCS(NFIT,3)**2*(LOG(VINT(2)/BCS(NFIT,4)))**4)+BCS(NFIT,5)*
  38      &VINT(2)**(BCS(NFIT,6)-1.)*SIN(0.5*PARU(1)*BCS(NFIT,6))
  39       SIGM=-BCS(NFIT,7)*VINT(2)**(BCS(NFIT,8)-1.)*
  40      &COS(0.5*PARU(1)*BCS(NFIT,8))
  41       REFP=BCS(NFIT,2)*PARU(1)*LOG(VINT(2)/BCS(NFIT,4))/
  42      &((1.-0.25*BCS(NFIT,3)*PARU(1)**2)**2+2.*BCS(NFIT,3)*
  43      &(1.+0.25*BCS(NFIT,3)*PARU(1)**2)+(LOG(VINT(2)/BCS(NFIT,4)))**2+
  44      &BCS(NFIT,3)**2*(LOG(VINT(2)/BCS(NFIT,4)))**4)-BCS(NFIT,5)*
  45      &VINT(2)**(BCS(NFIT,6)-1.)*COS(0.5*PARU(1)*BCS(NFIT,6))
  46       REFM=-BCS(NFIT,7)*VINT(2)**(BCS(NFIT,8)-1.)*
  47      &SIN(0.5*PARU(1)*BCS(NFIT,8))
  48       SIGMA=SIGP-ISIGN(1,MINT(11)*MINT(12))*SIGM
  49       RHO=(REFP-ISIGN(1,MINT(11)*MINT(12))*REFM)/SIGMA
  50
  51 C...Nuclear slope parameter B, curvature C:
  52       NFIT=1
  53       IF(MSTP(31).GE.4) NFIT=2
  54       BP=BCB(NFIT,1)+BCB(NFIT,2)*LOG(VINT(2))+
  55      &BCB(NFIT,3)*(LOG(VINT(2)))**2
  56       BM=BCB(NFIT,4)+BCB(NFIT,5)*LOG(VINT(2))
  57       B=BP-ISIGN(1,MINT(11)*MINT(12))*SIGM/SIGP*(BM-BP)
  58       VINT(121)=B
  59       C=-0.5*BCC(2)/BCC(3)*(1.-SQRT(MAX(0.,1.+4.*BCC(3)/BCC(2)**2*
  60      &(1.E-03*VINT(1)-BCC(1)))))
  61       VINT(122)=C
  62
  63 C...Elastic scattering cross-section (fixed by sigma-tot, rho and B).
  64       SIGEL=SIGMA**2*(1.+RHO**2)/(16.*PARU(1)*PARU(5)*B)
  65
  66 C...Single diffractive scattering cross-section from Goulianos:
  67       SIGSD=2.*0.68*(1.+36./VINT(2))*LOG(0.6+0.1*VINT(2))
  68
  69 C...Double diffractive scattering cross-section (essentially fixed by
  70 C...sigma-sd and sigma-el).
  71       SIGDD=SIGSD**2/(3.*SIGEL)
  72
  73 C...Total non-elastic, non-diffractive cross-section.
  74       SIGND=SIGMA-SIGDD-SIGSD-SIGEL
  75
  76 C...Rescale for pions.
  77       IF(IABS(MINT(11)).EQ.211.AND.IABS(MINT(12)).EQ.211) THEN
  78         SIGMA=4./9.*SIGMA
  79         SIGDD=4./9.*SIGDD
  80         SIGSD=4./9.*SIGSD
  81         SIGEL=4./9.*SIGEL
  82         SIGND=4./9.*SIGND
  83       ELSEIF(IABS(MINT(11)).EQ.211.OR.IABS(MINT(12)).EQ.211) THEN
  84         SIGMA=2./3.*SIGMA
  85         SIGDD=2./3.*SIGDD
  86         SIGSD=2./3.*SIGSD
  87         SIGEL=2./3.*SIGEL
  88         SIGND=2./3.*SIGND
  89       ENDIF
  90
  91 C...Save cross-sections in common block PYPARA.
  92       VINT(101)=SIGMA
  93       VINT(102)=SIGEL
  94       VINT(103)=SIGSD
  95       VINT(104)=SIGDD
  96       VINT(106)=SIGND
  97       XSEC(95,1)=SIGND
  98
  99       RETURN
 100       END