Patch for the tracker

[u/mrichter/AliRoot.git] / PYTHIA6 / pythia6214.f

diff --git a/PYTHIA6/pythia6214.f b/PYTHIA6/pythia6214.f
index 02a2088d5fcd9f703eee440c1e0109c5fd6e1755..6a9b73c5c894e70ae604b899039d835d5287caa5 100644 (file)
--- a/PYTHIA6/pythia6214.f
+++ b/PYTHIA6/pythia6214.f
@@ -286,7 +286,7 @@ C...and particle, decay and process data.
 C...Double precision and integer declarations.
       IMPLICIT DOUBLE PRECISION(A-H, O-Z)
       IMPLICIT INTEGER(I-N)
-      INTEGER PYK,PYCHGE,PYCOMP
+C      INTEGER PYK,PYCHGE,PYCOMP
 C...Commonblocks.
       COMMON/PYDAT1/MSTU(200),PARU(200),MSTJ(200),PARJ(200)
       COMMON/PYDAT2/KCHG(500,4),PMAS(500,4),PARF(2000),VCKM(4,4)
@@ -2563,8 +2563,8 @@ C...Local arrays and character variables.
       CHARACTER CHFRAM*12,CHBEAM*12,CHTARG*12,CHLH(2)*6
  
 C...Interface to PDFLIB.
-      COMMON/W50512/QCDL4,QCDL5
-      SAVE /W50512/
+      COMMON/LW50512/QCDL4,QCDL5
+      SAVE /LW50512/
       DOUBLE PRECISION VALUE(20),QCDL4,QCDL5
       CHARACTER*20 PARM(20)
       DATA VALUE/20*0D0/,PARM/20*' '/
@@ -2856,7 +2856,6 @@ C...Stop if no subprocesses on.
         WRITE(MSTU(11),5100)
         STOP
       ENDIF
- 
 C...Initial values for some counters.
       N=0
       MINT(5)=MINT(5)+1
@@ -27692,8 +27691,8 @@ C...Local arrays.
      &XPPI(-6:6),XPPR(-6:6)
  
 C...Interface to PDFLIB.
-      COMMON/W50513/XMIN,XMAX,Q2MIN,Q2MAX
-      SAVE /W50513/
+      COMMON/LW50513/XMIN,XMAX,Q2MIN,Q2MAX
+      SAVE /LW50513/
       DOUBLE PRECISION XX,QQ,UPV,DNV,USEA,DSEA,STR,CHM,BOT,TOP,GLU,
      &VALUE(20),XMIN,XMAX,Q2MIN,Q2MAX
       CHARACTER*20 PARM(20)
@@ -28358,8 +28357,8 @@ C...Local arrays.
       DIMENSION XPEL(-25:25),XPGA(-6:6),SXP(0:6)
  
 C...Interface to PDFLIB.
-      COMMON/W50513/XMIN,XMAX,Q2MIN,Q2MAX
-      SAVE /W50513/
+      COMMON/LW50513/XMIN,XMAX,Q2MIN,Q2MAX
+      SAVE /LW50513/
       DOUBLE PRECISION XX,QQ,UPV,DNV,USEA,DSEA,STR,CHM,BOT,TOP,GLU,
      &VALUE(20),XMIN,XMAX,Q2MIN,Q2MAX
       CHARACTER*20 PARM(20)
@@ -45412,7 +45411,6 @@ C...Commonblocks.
       SAVE /PYJETS/,/PYDAT1/,/PYDAT2/,/PYDAT3/,/PYINT4/
 C...Local array.
       DIMENSION PS(2,6),IJOIN(100)
- 
 C...Initialize and reset.
       MSTU(24)=0
       IF(MSTU(12).GE.1) CALL PYLIST(0)
@@ -50099,6 +50097,41 @@ C.. Form baryon. Distinguish Lambda- and Sigmalike baryons.
         KF=ISIGN(1000*KFLD+100*KFLE+10*KFLF+KFLS,KFL1)
         IF(KSIG.EQ.0) KF=ISIGN(1000*KFLD+100*KFLF+10*KFLE+KFLS,KFL1)
       ENDIF
+C -------------------------------------------------------------------------
+C Extracted from a private e-mail exchange with Torbjorn Sjostrand
+C 
+C No, Lambda(1520) is not included and not foreseen.
+C So if you want it in Pythia, it would have to be a hack.
+C What you could do is:
+C 1) In PYKFDI, just before the RETURN above label 140, you could check if
+C a Lambda, Sigma0 or Sigma*0 has been produced, and with some small
+C probability switch such a particle to the Lambda(1520) code. That is,
+C if KF = 3122, 3212, or 3214 and a random number below some number, switch
+C to KF = 3124. (And correspondingly for anticparticles.)
+C 2) Use the PYUPDA routine (see manual) to include particle and decay data
+C for the Lambda(1520).
+C -------------------------------------------------------------------------
+ 
+C      IF (IABS(KF).EQ.3122) THEN
+C     Converting a fraction (0.20) of Lambda0 to Lambda(1520) + c.c.
+C     This fraction is based on the experimental measurement at ISR
+C     Bobbink 83, NP B217,11 (1983)
+C     The region 0.5 < XF < 1.0 has been extrapolated to XF=0
+C         IF(PYR(0).LE.0.20) KF=ISIGN(3124,KF)
+C      ENDIF
+
+C      IF(IABS(KF).EQ.3212) THEN
+C     Converting a fraction (0.20) of Sigma0 to Lambda(1520) + c.c.
+C     We suppose the same fraction as for Lambda0
+C         IF(PYR(0).LE.0.20) KF=ISIGN(3124,KF)
+C      ENDIF
+
+C      IF (IABS(KF).EQ.3214) THEN
+C     Converting a fraction (0.30) of Sigma0(1385) to Lambda(1520) + c.c.
+C     This is conservative extimate supposing that the ratio
+C     scales as (M_Sigma1385/M_Lambda0)^2 ~ 1.5 
+C         IF(PYR(0).LE.0.30) KF=ISIGN(3124,KF)
+C      ENDIF
       RETURN
  
 C...Use tabulated probabilities to select new flavour and hadron.
@@ -51380,10 +51413,14 @@ C...Calculate allowed z range.
  
 C...Integral of Altarelli-Parisi z kernel for QCD.
 C...(Includes squark and gluino; with factor N_C/C_F extra for latter).
+
+      FMED = PARJ(200)
       IF(MSTJ(49).EQ.0.AND.KFL(1).EQ.21) THEN
-        FBR=6D0*LOG((1D0-ZC)/ZC)+MSTJ(45)*0.5D0
+C Nestor
+        FBR=(1.D0+FMED)*6D0*LOG((1D0-ZC)/ZC)+MSTJ(45)*0.5D0
       ELSEIF(MSTJ(49).EQ.0) THEN
-        FBR=(8D0/3D0)*LOG((1D0-ZC)/ZC)
+C Nestor
+        FBR=(1.D0+FMED)*(8D0/3D0)*LOG((1D0-ZC)/ZC)
         IF(IGLUI.EQ.1.AND.IR.GE.31) FBR=FBR*(9D0/4D0)
  
 C...Integral of Altarelli-Parisi z kernel for scalar gluon.
@@ -51395,9 +51432,9 @@ C...Integral of Altarelli-Parisi z kernel for scalar gluon.
  
 C...Integral of Altarelli-Parisi z kernel for Abelian vector gluon.
       ELSEIF(KFL(1).EQ.21) THEN
-        FBR=6D0*MSTJ(45)*(0.5D0-ZC)
+        FBR=(1.D0+FMED)*6D0*MSTJ(45)*(0.5D0-ZC)
       ELSE
-        FBR=2D0*LOG((1D0-ZC)/ZC)
+        FBR=(1.D0+FMED)*2D0*LOG((1D0-ZC)/ZC)
       ENDIF
  
 C...Reset QCD probability for colourless.