From 7935c2c73ac3aee3cfeca76998abaed953dbc850 Mon Sep 17 00:00:00 2001
From: morsch <morsch@f7af4fe6-9843-0410-8265-dc069ae4e863>
Date: Mon, 11 Aug 2003 13:49:59 +0000
Subject: [PATCH] Updates for B->J/Psi (psi') X decays.

---
 PYTHIA6/AliDecayerPythia.cxx | 59 ++++++++++++++++++++++++++++--------
 PYTHIA6/AliDecayerPythia.h   |  1 +
 2 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/PYTHIA6/AliDecayerPythia.cxx b/PYTHIA6/AliDecayerPythia.cxx
index 491f93a08c7..2372c6661ae 100644
--- a/PYTHIA6/AliDecayerPythia.cxx
+++ b/PYTHIA6/AliDecayerPythia.cxx
@@ -119,6 +119,8 @@ void AliDecayerPythia::ForceDecay()
 
 //
 // select mode    
+    Int_t products[2];
+    Int_t mult[2];
 
     switch (decay) 
     {
@@ -143,10 +145,10 @@ void AliDecayerPythia::ForceDecay()
 	ForceParticleDecay(  223,13,2); // omega
 	ForceParticleDecay(  333,13,2); // phi
 	ForceParticleDecay(  443,13,2); // J/Psi
-	ForceParticleDecay(100443,13,2); // Psi'
+	ForceParticleDecay(100443,13,2);// Psi'
 	ForceParticleDecay(  553,13,2); // Upsilon
-	ForceParticleDecay(100553,13,2); // Upsilon'
-	ForceParticleDecay(200553,13,2); // Upsilon''
+	ForceParticleDecay(100553,13,2);// Upsilon'
+	ForceParticleDecay(200553,13,2);// Upsilon''
 	break;
     case kSemiElectronic:
 	ForceParticleDecay(  411,11,1); // D+/-     
@@ -169,17 +171,24 @@ void AliDecayerPythia::ForceDecay()
 	ForceParticleDecay(  221,11,2); // eta
 	ForceParticleDecay(  223,11,2); // omega
 	ForceParticleDecay(  443,11,2); // J/Psi
-	ForceParticleDecay(100443,11,2); // Psi'
+	ForceParticleDecay(100443,11,2);// Psi'
 	ForceParticleDecay(  553,11,2); // Upsilon
-	ForceParticleDecay(100553,11,2); // Upsilon'
-	ForceParticleDecay(200553,11,2); // Upsilon''
+	ForceParticleDecay(100553,11,2);// Upsilon'
+	ForceParticleDecay(200553,11,2);// Upsilon''
 	break;
     case kBJpsiDiMuon:
-	ForceParticleDecay(  511,443,1); // B0     
-	ForceParticleDecay(  521,443,1); // B+/-     
-	ForceParticleDecay(  531,443,1); // B_s     
-	ForceParticleDecay( 5122,443,1); // Lambda_b
-	ForceParticleDecay(  443,13,2);  // J/Psi    
+
+	products[0] =    443;
+	products[1] = 100443;
+	mult[0] = 1;
+	mult[1] = 1;
+
+	ForceParticleDecay(  511, products, mult, 2); // B0   -> J/Psi (Psi') X   
+	ForceParticleDecay(  521, products, mult, 2); // B+/- -> J/Psi (Psi') X     
+	ForceParticleDecay(  531, products, mult, 2); // B_s  -> J/Psi (Psi') X     
+	ForceParticleDecay( 5122, products, mult, 2); // Lambda_b -> J/Psi (Psi') X 
+	ForceParticleDecay( 100443, 443, 1);          // Psi'  -> J/Psi X    
+	ForceParticleDecay(    443,13,2);             // J/Psi -> mu+ mu-   
 	break;
     case kBPsiPrimeDiMuon:
 	ForceParticleDecay(  511,30443,1); // B0     
@@ -292,7 +301,7 @@ void AliDecayerPythia::ForceHadronicD()
 void AliDecayerPythia::ForceParticleDecay(Int_t particle, Int_t product, Int_t mult)
 {
 //
-//  force decay of particle into products with multiplicity mult
+//  Force decay of particle into products with multiplicity mult
 
     Int_t kc=fPythia->Pycomp(particle);
     fPythia->SetMDCY(kc,1,1);
@@ -311,6 +320,32 @@ void AliDecayerPythia::ForceParticleDecay(Int_t particle, Int_t product, Int_t m
     }
 }
 
+void AliDecayerPythia::ForceParticleDecay(Int_t particle, Int_t* products, Int_t* mult, Int_t npart)
+{
+//
+//  Force decay of particle into products with multiplicity mult
+
+    Int_t kc=fPythia->Pycomp(particle);
+    fPythia->SetMDCY(kc,1,1);
+    Int_t ifirst=fPythia->GetMDCY(kc,2);
+    Int_t ilast=ifirst+fPythia->GetMDCY(kc,3)-1;
+    fBraPart[kc] = 1;
+//
+//  Loop over decay channels
+    for (Int_t channel = ifirst; channel <= ilast; channel++) {
+	Int_t nprod = 0;
+	for (Int_t i = 0; i < npart; i++) {
+	    nprod += (CountProducts(channel, products[i]) >= mult[i]);
+	}
+	if (nprod) {
+	    fPythia->SetMDME(channel,1,1);
+	} else {
+	    fPythia->SetMDME(channel,1,0);
+	    fBraPart[kc]-=fPythia->GetBRAT(channel);
+	}
+    }
+}
+
 void AliDecayerPythia::DefineParticles()
 {
 //
diff --git a/PYTHIA6/AliDecayerPythia.h b/PYTHIA6/AliDecayerPythia.h
index 14f9d865f7f..b6047bd3e59 100644
--- a/PYTHIA6/AliDecayerPythia.h
+++ b/PYTHIA6/AliDecayerPythia.h
@@ -39,6 +39,7 @@ public AliDecayer
 		    Double_t mom, Double_t theta, Double_t phi);
     Int_t    CountProducts(Int_t channel, Int_t particle);
     void     ForceParticleDecay(Int_t particle, Int_t product, Int_t mult);
+    void     ForceParticleDecay(Int_t particle, Int_t* products, Int_t* mult, Int_t npart);
     void     ForceHadronicD();
     void     ForceOmega();    
     Float_t  GetBraPart(Int_t kf);
-- 
2.31.1