diff --git a/EvtGenBase/EvtTensorParticle.hh b/EvtGenBase/EvtTensorParticle.hh
--- a/EvtGenBase/EvtTensorParticle.hh
+++ b/EvtGenBase/EvtTensorParticle.hh
@@ -24,6 +24,8 @@
 #include "EvtGenBase/EvtParticle.hh"
 #include "EvtGenBase/EvtTensor4C.hh"
 
+#include <array>
+
 class EvtTensorParticle : public EvtParticle {
   public:
     EvtTensorParticle() = default;
@@ -42,7 +44,7 @@
                                           double gamma ) const override;
 
   private:
-    EvtTensor4C eps[5];    //eps1,eps2,eps3,eps4,eps5;
+    std::array<EvtTensor4C, 5> eps;    //eps1,eps2,eps3,eps4,eps5;
 
     EvtTensorParticle( const EvtTensorParticle& tensor );
     EvtTensorParticle& operator=( const EvtTensorParticle& tensor );
diff --git a/EvtGenBase/EvtVectorParticle.hh b/EvtGenBase/EvtVectorParticle.hh
--- a/EvtGenBase/EvtVectorParticle.hh
+++ b/EvtGenBase/EvtVectorParticle.hh
@@ -25,6 +25,9 @@
 #include "EvtGenBase/EvtVector4C.hh"
 #include "EvtGenBase/EvtVector4R.hh"
 
+#include <array>
+#include <cassert>
+
 class EvtId;
 
 class EvtVectorParticle : public EvtParticle {
@@ -37,15 +40,22 @@
                const EvtVector4C&, const EvtVector4C& );
     EvtVector4C epsParent( int i ) const override
     {
+        assert( i >= 0 && i < _eps.size() );
+
         return boostTo( _eps[i], this->getP4() );
     }
-    EvtVector4C eps( int i ) const override { return _eps[i]; }
+    EvtVector4C eps( int i ) const override
+    {
+        assert( i >= 0 && i < _eps.size() );
+
+        return _eps[i];
+    }
     EvtSpinDensity rotateToHelicityBasis() const override;
     EvtSpinDensity rotateToHelicityBasis( double alpha, double beta,
                                           double gamma ) const override;
 
   private:
-    EvtVector4C _eps[3];
+    std::array<EvtVector4C, 3> _eps;
 
     EvtVectorParticle( const EvtVectorParticle& vector );
     EvtVectorParticle& operator=( const EvtVectorParticle& vector );
diff --git a/History.md b/History.md
--- a/History.md
+++ b/History.md
@@ -12,6 +12,9 @@
 ## R02-0X-00
 
 19 Feb 2024 Fernando Abudinen
+* D108: Bugfix protect polarisation vector for vector and tensor particles against wrong indices
+
+19 Feb 2024 Fernando Abudinen
 * D107: Implement const correctness for epsPhoton and epsParentPhoton
 
 3 Feb 2024 John Back
diff --git a/src/EvtGenBase/EvtTensorParticle.cpp b/src/EvtGenBase/EvtTensorParticle.cpp
--- a/src/EvtGenBase/EvtTensorParticle.cpp
+++ b/src/EvtGenBase/EvtTensorParticle.cpp
@@ -27,6 +27,7 @@
 #include "EvtGenBase/EvtVector4C.hh"
 #include "EvtGenBase/EvtVector4R.hh"
 
+#include <cassert>
 #include <iostream>
 #include <math.h>
 #include <stdlib.h>
@@ -84,15 +85,15 @@
 
 EvtTensor4C EvtTensorParticle::epsTensorParent( int i ) const
 {
-    EvtTensor4C temp = eps[i];
+    assert( i >= 0 && i < eps.size() );
 
-    temp.applyBoostTo( this->getP4() );
-    return temp;
+    return boostTo( eps[i], this->getP4() );
 
 }    //epsParent
 
 EvtTensor4C EvtTensorParticle::epsTensor( int i ) const
 {
+    assert( i >= 0 && i < eps.size() );
     return eps[i];
 
 }    //eps
diff --git a/src/EvtGenModels/EvtBcToNPi.cpp b/src/EvtGenModels/EvtBcToNPi.cpp
--- a/src/EvtGenModels/EvtBcToNPi.cpp
+++ b/src/EvtGenModels/EvtBcToNPi.cpp
@@ -301,7 +301,7 @@
             2 * I * FV * dual( EvtGenFunctions::directProd( p, k ) );
         EvtVector4C Heps = H.cont2( hardCur );
 
-        for ( int i = 0; i < 4; i++ ) {
+        for ( int i = 0; i < 3; i++ ) {
             EvtVector4C eps = root_particle->getDaug( 0 )
                                   ->epsParent( i )
                                   .conj();    // psi-meson polarization vector
diff --git a/src/EvtGenModels/EvtBcVNpi.cpp b/src/EvtGenModels/EvtBcVNpi.cpp
--- a/src/EvtGenModels/EvtBcVNpi.cpp
+++ b/src/EvtGenModels/EvtBcVNpi.cpp
@@ -183,7 +183,7 @@
     H.addDirProd( ( a0f - a3f ) * 2.0 * ( m_meson / Q2 ) * p4b, p4b - p4meson );
     EvtVector4C Heps = H.cont2( hardCur );
 
-    for ( int i = 0; i < 4; i++ ) {
+    for ( int i = 0; i < 3; i++ ) {
         EvtVector4C eps = root_particle->getDaug( 0 )
                               ->epsParent( i )
                               .conj();    // psi-meson polarization vector