From fb629e2dc5d9c974ca659a1d42d16330310d12b4 Mon Sep 17 00:00:00 2001
From: skowron <skowron@f7af4fe6-9843-0410-8265-dc069ae4e863>
Date: Thu, 15 Jul 2004 10:37:53 +0000
Subject: [PATCH] Bug Correction

---
 ANALYSIS/AliAODPair.cxx | 24 ++++++++++++++++++++++++
 ANALYSIS/AliAODPair.h   |  9 ++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/ANALYSIS/AliAODPair.cxx b/ANALYSIS/AliAODPair.cxx
index acd30e75f4b..da609d3a056 100644
--- a/ANALYSIS/AliAODPair.cxx
+++ b/ANALYSIS/AliAODPair.cxx
@@ -29,6 +29,8 @@ AliAODPair::AliAODPair(Bool_t rev):
  fQLongLCMSNotCalc(kTRUE),
  fQtLCMS(0.0),
  fQtLCMSNotCalc(kTRUE),
+ fQt(0.0),
+ fQtNotCalc(kTRUE),
  fQInv(0.0),
  fQInvNotCalc(kTRUE),
  fInvMass(0.0),
@@ -314,6 +316,28 @@ Double_t AliAODPair::GetQtLCMS()
   }
  return fQtLCMS; 
 }
+/************************************************************************/
+
+Double_t AliAODPair::GetQt()
+{
+ //returns Q transverse CMS longitudionally co-moving
+ if (fQtNotCalc)
+  {
+    Double_t dotprod = fPxSum*fPxDiff + fPySum*fPyDiff + fPzSum*fPzDiff;
+    Double_t klen =    fPxSum*fPxSum  + fPySum*fPySum  + fPzSum*fPzSum;
+    klen = TMath::Sqrt(klen);
+    Double_t qlen =    fPxDiff*fPxDiff + fPyDiff*fPyDiff + fPzDiff*fPzDiff;
+    qlen = TMath::Sqrt(qlen);
+    
+    Double_t cosopenangle = dotprod/(klen*qlen);
+    Double_t sinopenangle = TMath::Sqrt(1.0 - cosopenangle*cosopenangle);
+    
+    fQt = sinopenangle*qlen;
+    fQtNotCalc = kFALSE;
+  }
+ return fQt; 
+}
+/************************************************************************/
 
 Double_t AliAODPair::GetKt()
 {
diff --git a/ANALYSIS/AliAODPair.h b/ANALYSIS/AliAODPair.h
index 83dab89b663..f8de3c9cbed 100644
--- a/ANALYSIS/AliAODPair.h
+++ b/ANALYSIS/AliAODPair.h
@@ -43,6 +43,7 @@ class AliAODPair: public TObject
    virtual Double_t GetQLongLCMS(); //returns Q Long CMS longitudionally co-moving
    virtual Double_t GetQtLCMS(); //returns Q transverse CMS longitudionally co-moving
    
+   virtual Double_t GetQt(); //returns Q transverse to Kt
    
    
    virtual Double_t GetKt();  //returns K transverse
@@ -82,8 +83,12 @@ class AliAODPair: public TObject
    Double_t fQLongLCMS; //value of Q long CMS longitudially co-moving
    Bool_t   fQLongLCMSNotCalc;//flag indicating if fQLongLCMS is already calculated for this pair
    
-   Double_t fQtLCMS; //value of Q long CMS longitudially co-moving
+   Double_t fQtLCMS; //value of Qt CMS longitudially co-moving (hypot(qsidelcms,qoutlcms))
    Bool_t   fQtLCMSNotCalc;//flag indicating if fQLongLCMS is already calculated for this pair
+
+   Double_t fQt; //value of Qt, projection of 3-mom diff to Kt
+   Bool_t   fQtNotCalc;//flag indicating if fQt is already calculated for this pair
+   
 /************************************************************/
 /************************************************************/
    Double_t fQInv;  //half of differnece of 4-momenta
@@ -173,6 +178,8 @@ void AliAODPair::Changed()
  fQSideLCMSNotCalc = kTRUE;
  fQOutLCMSNotCalc  = kTRUE;
  fQLongLCMSNotCalc = kTRUE;
+ fQtLCMSNotCalc    = kTRUE;
+ fQtNotCalc        = kTRUE;
  fKtNotCalc         = kTRUE;
  fKStarNotCalc      = kTRUE;
  fQInvLNotCalc      = kTRUE;
-- 
2.39.3