Tuned pp-min.bias settings (M.Monteno, R.Ugoccioni and N.Carrer)

diff --git a/EVGEN/AliPythia.cxx b/EVGEN/AliPythia.cxx
index b81d81cadb162736a12a777914ea742e799e3b33..61c749890674febbb98c3af148f681c74d4060d6 100644 (file)
--- a/EVGEN/AliPythia.cxx
+++ b/EVGEN/AliPythia.cxx
@@ -15,6 +15,10 @@
 
 /*
 $Log$
+Revision 1.17  2001/12/19 15:40:43  morsch
+For kPyJets enforce simple jet topology, i.e no initial or final state
+gluon radiation and no primordial pT.
+
 Revision 1.16  2001/10/12 11:13:59  morsch
 Missing break statements added (thanks to Nicola Carrer)
 
@@ -153,25 +157,19 @@ void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfun
     case kPyMb:
 // Minimum Bias pp-Collisions
 //
-// Tuning of parameters descibed in G. Ciapetti and A. Di Ciaccio
-// Proc. of the LHC Workshop, Aachen 1990, Vol. II p. 155
 //   
 //      select Pythia min. bias model
        SetMSEL(0);
-       SetMSUB(92,1);
-       SetMSUB(93,1);
-       SetMSUB(94,1);
-       SetMSUB(95,1);  
-//      Multiple interactions switched on
-       SetMSTP(81,1);
-       SetMSTP(82,2);
-//      Low-pT cut-off for hard scattering
-       SetPARP(81,1.9);
-//      model for subsequent non-hardest interaction
-//     90% gg->gg 10% gg->qq
-       SetPARP(86,0.9);
-//      90% of gluon interactions have minimum string length
-       SetPARP(85,0.9);
+       SetMSUB(92,1);      // single diffraction AB-->XB
+       SetMSUB(93,1);      // single diffraction AB-->AX
+       SetMSUB(94,1);      // double diffraction
+       SetMSUB(95,1);      // low pt production
+       SetMSTP(81,1);      // multiple interactions switched on
+       SetMSTP(82,3);      // model with varying impact param. & a single Gaussian
+       SetPARP(82,3.47);   // set value pT_0  for turn-off of the cross section of                  
+                            // multiple interaction at a reference energy = 14000 GeV
+       SetPARP(89,14000.); // reference energy for the above parameter
+       SetPARP(90,0.174);  // set exponent for energy dependence of pT_0 
        break;
     case kPyJets:
        SetMSEL(1);
@@ -192,7 +190,7 @@ void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfun
     }
 //
 //  Initialize PYTHIA
-    SetMSTP(41,1);
+    SetMSTP(41,1);   // all resonance decays switched on
 
     Initialize("CMS","p","p",fEcms);
 

diff --git a/EVGEN/AliPythia.h b/EVGEN/AliPythia.h
index 0f3698f733a0411d4b46893d13fb84af817fced9..8108a61bf471224ba8e626a0e9c26aedb3fb8901 100644 (file)
--- a/EVGEN/AliPythia.h
+++ b/EVGEN/AliPythia.h
@@ -21,6 +21,7 @@ typedef enum
     kMRS_D0=3030,
     kMRS_G=3041,
     kCTEQ_2pM=4024,
+    kCTEQ_4L=4032,
     kCTEQ_4M=4034,
     kMRST_cg_LO=3072,
     kCTEQ_5L=4046,