diff --git a/examples/smearing/lutRead.C b/examples/smearing/lutRead.C
index d43fee4..9226aa1 100644
--- a/examples/smearing/lutRead.C
+++ b/examples/smearing/lutRead.C
@@ -1,5 +1,6 @@
 enum EWhat {
   kEfficiency,
+  kEfficiency2,
   kEfficiencyInnerTOF,
   kEfficiencyOuterTOF,
   kPtResolution,
@@ -44,6 +45,7 @@ lutRead(int pdg, const char *filename, int what, int vs, float nch = 0., float r
     if (vs == kPt)  cen = lutEntry->pt;
     double val = 0.;
     if (what == kEfficiency)         val = lutEntry->eff * 100.; // efficiency (%)
+    if (what == kEfficiency2)        val = lutEntry->eff2 * 100.; // efficiency (%)
     if (what == kEfficiencyInnerTOF) val = lutEntry->itof * 100.; // efficiency (%)
     if (what == kEfficiencyOuterTOF) val = lutEntry->otof * 100.; // efficiency (%)
     if (what == kPtResolution)   val = sqrt(lutEntry->covm[14]) * lutEntry->pt * 100.; // pt resolution (%)
diff --git a/src/TrackSmearer.cc b/src/TrackSmearer.cc
index 9a17fa8..598164d 100644
--- a/src/TrackSmearer.cc
+++ b/src/TrackSmearer.cc
@@ -96,8 +96,13 @@ bool
 TrackSmearer::smearTrack(O2Track &o2track, lutEntry_t *lutEntry)
 {
   // generate efficiency
-  if (mUseEfficiency && (gRandom->Uniform() > lutEntry->eff))
-    return false;
+  if (mUseEfficiency) {
+    auto eff = 0.;
+    if (mWhatEfficiency == 1) eff = lutEntry->eff;
+    if (mWhatEfficiency == 2) eff = lutEntry->eff2;
+    if (gRandom->Uniform() > eff)
+      return false;
+  }
   // transform params vector and smear
   double params_[5];
   for (int i = 0; i < 5; ++i) {
diff --git a/src/TrackSmearer.hh b/src/TrackSmearer.hh
index b6af3f8..4f3bc70 100644
--- a/src/TrackSmearer.hh
+++ b/src/TrackSmearer.hh
@@ -25,6 +25,7 @@ public:
   /** LUT methods **/
   bool loadTable(int pdg, const char *filename, bool forceReload = false);
   void useEfficiency(bool val) { mUseEfficiency = val; };
+  void setWhatEfficiency(int val) { mWhatEfficiency = val; };
   lutHeader_t *getLUTHeader(int pdg) { return mLUTHeader[getIndexPDG(pdg)]; };
   lutEntry_t *getLUTEntry(int pdg, float nch, float radius, float eta, float pt);
 
@@ -53,6 +54,7 @@ protected:
   lutHeader_t *mLUTHeader[nLUTs] = {nullptr};
   lutEntry_t *****mLUTEntry[nLUTs] = {nullptr};
   bool mUseEfficiency = true;
+  int mWhatEfficiency = 1;
   float mdNdEta =  1600.;
   
 };
diff --git a/src/lutCovm.hh b/src/lutCovm.hh
index 8cb8c6a..acceefd 100644
--- a/src/lutCovm.hh
+++ b/src/lutCovm.hh
@@ -2,7 +2,7 @@
 /// @email: preghenella@bo.infn.it
 
 #pragma once
-#define LUTCOVM_VERSION 20210731
+#define LUTCOVM_VERSION 20210801
 
 struct map_t {
   int nbins = 1;
@@ -56,6 +56,7 @@ struct lutEntry_t {
   float pt = 0.;
   bool valid = false;
   float eff = 0.; 
+  float eff2 = 0.; 
   float itof = 0.;
   float otof = 0.;
   float covm[15] = {0.};
diff --git a/src/lutWrite.cc b/src/lutWrite.cc
index 90fc7fa..371bb1a 100644
--- a/src/lutWrite.cc
+++ b/src/lutWrite.cc
@@ -23,11 +23,28 @@ fatSolve(lutEntry_t &lutEntry, float pt = 0.1, float eta = 0.0, float mass = 0.1
   if (!trPtr) return false;
 
   lutEntry.valid = true;
-  lutEntry.eff = fat.GetGoodHitProb(0);
   lutEntry.itof = fat.GetGoodHitProb(itof);
   lutEntry.otof = fat.GetGoodHitProb(otof);
   for (int i = 0; i < 15; ++i) lutEntry.covm[i] = trPtr->GetCovariance()[i];
-  
+
+  // define the efficiency
+  auto totfake = 0.;
+  lutEntry.eff = 1.;
+  for (int i = 1; i < 20; ++i) {
+    auto igoodhit = fat.GetGoodHitProb(i);
+    if (igoodhit <= 0. || i == itof || i == otof) continue;
+    lutEntry.eff *= igoodhit;
+    auto pairfake = 0.;
+    for (int j = i + 1; j < 20; ++j) {
+      auto jgoodhit = fat.GetGoodHitProb(j);
+      if (jgoodhit <= 0. || j == itof || j == otof) continue;
+      pairfake = (1. - igoodhit) * (1. - jgoodhit);
+      break;
+    }
+    totfake += pairfake;
+  }
+  lutEntry.eff2 = (1. - totfake);
+
   return true;
 }
 
@@ -164,6 +181,7 @@ lutWrite(const char *filename = "lutCovm.dat", int pdg = 211, float field = 0.2,
 	      //	      printf(" --- fatSolve: error \n");
 	      lutEntry.valid = false;
               lutEntry.eff = 0.;
+              lutEntry.eff2 = 0.;
 	      for (int i = 0; i < 15; ++i)
 		lutEntry.covm[i] = 0.;
 	    }
@@ -171,6 +189,7 @@ lutWrite(const char *filename = "lutCovm.dat", int pdg = 211, float field = 0.2,
 	  else {
 	    //	    printf(" --- fwdSolve: pt = %f, eta = %f, mass = %f, field=%f \n", lutEntry.pt, lutEntry.eta, lutHeader.mass, lutHeader.field);
 	    lutEntry.eff = 1.;
+	    lutEntry.eff2 = 1.;
             bool retval = true;
             if (usePara) {
 	      retval = fwdPara(lutEntry, lutEntry.pt, lutEntry.eta, lutHeader.mass, field);