MSTU(16) = 2 for all processes.

diff --git a/PYTHIA6/AliPythia.cxx b/PYTHIA6/AliPythia.cxx
index e98836f31a74c5f3e2ffb04ad88d8d12e27574c1..f58c91526a8fb86a212464c84698697005b3d12e 100644 (file)
--- a/PYTHIA6/AliPythia.cxx
+++ b/PYTHIA6/AliPythia.cxx
@@ -81,10 +81,13 @@ void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfun
     SetMDCY(Pycomp(3312),1,0);
     SetMDCY(Pycomp(3322),1,0);
     SetMDCY(Pycomp(3334),1,0);
-    //  select structure function 
+    // Select structure function 
     SetMSTP(52,2);
     SetMSTP(51,strucfunc);
-    
+    // Particles produced in string fragmentation point directly to either of the two endpoints
+    // of the string (depending in the side they were generated from).
+    SetMSTU(16,2);
+
 //
 // Pythia initialisation for selected processes//
 //
@@ -154,7 +157,6 @@ void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfun
 //  heavy quark masses
 
        SetPMAS(4,1,1.2);
-       SetMSTU(16,2);
 //
 //    primordial pT
        SetMSTP(91,1);
@@ -165,7 +167,6 @@ void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfun
     case kPyBeauty:
        SetMSEL(5);
        SetPMAS(5,1,4.75);
-       SetMSTU(16,2);
        break;
     case kPyJpsi:
        SetMSEL(0);
@@ -185,7 +186,6 @@ void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfun
        break;
     case kPyCharmUnforced:
        SetMSEL(0);
-       SetMSTU(16,2);
 // gq->qg   
        SetMSUB(28,1);
 // gg->qq
@@ -194,7 +194,6 @@ void AliPythia::ProcInit(Process_t process, Float_t energy, StrucFunc_t strucfun
        SetMSUB(68,1);
        break;
     case kPyBeautyUnforced:
-       SetMSTU(16,2);
        SetMSEL(0);
 // gq->qg   
        SetMSUB(28,1);
@@ -1184,7 +1183,6 @@ void AliPythia::ConfigHeavyFlavor()
     // QCD scales
     SetMSTP(32,2);
     SetPARP(34,1.0);
-    SetMSTU(16,2);
 }
 
 void AliPythia::AtlasTuning()