diff --git a/math/physics/inc/TLorentzVector.h b/math/physics/inc/TLorentzVector.h
index 62996364a42a69a7326d30f4ad95f50d11cd766f..f5c58ba1ace5994c16ee1cb8a6d5b039f260ad1b 100644
--- a/math/physics/inc/TLorentzVector.h
+++ b/math/physics/inc/TLorentzVector.h
@@ -47,8 +47,9 @@ public:
    enum { kX=0, kY=1, kZ=2, kT=3, kNUM_COORDINATES=4, kSIZE=kNUM_COORDINATES };
    // Safe indexing of the coordinates when using with matrices, arrays, etc.
 
-   TLorentzVector(Double_t x = 0.0, Double_t y = 0.0,
-                 Double_t z = 0.0, Double_t t = 0.0);
+   TLorentzVector();
+
+   TLorentzVector(Double_t x, Double_t y, Double_t z, Double_t t);
    // Constructor giving the components x, y, z, t.
 
    TLorentzVector(const Double_t * carray);
diff --git a/math/physics/inc/TVector3.h b/math/physics/inc/TVector3.h
index 7ed03b0f6ed7c2470e4842a8bb358b1488e01ed8..a6df2e07fef5675821f5085956e2f6869417506f 100644
--- a/math/physics/inc/TVector3.h
+++ b/math/physics/inc/TVector3.h
@@ -28,8 +28,9 @@ class TVector3 : public TObject {
 
 public:
 
+   TVector3();
 
-   TVector3(Double_t x = 0.0, Double_t y = 0.0, Double_t z = 0.0);
+   TVector3(Double_t x, Double_t y, Double_t z);
    // The constructor.
 
    TVector3(const Double_t *);
diff --git a/math/physics/src/TLorentzVector.cxx b/math/physics/src/TLorentzVector.cxx
index e9c6aee7cfb5850b27d684dd17111d7a144a97b5..ae61720999a587c8c137c17a874f13e56e2ede42 100644
--- a/math/physics/src/TLorentzVector.cxx
+++ b/math/physics/src/TLorentzVector.cxx
@@ -243,6 +243,9 @@ v *= l;&nbsp; // Attention v = l*v</TT>
 
 ClassImp(TLorentzVector)
 
+TLorentzVector::TLorentzVector()
+               : fP(), fE(0.0) {}
+
 TLorentzVector::TLorentzVector(Double_t x, Double_t y, Double_t z, Double_t t)
                : fP(x,y,z), fE(t) {}
 
diff --git a/math/physics/src/TVector3.cxx b/math/physics/src/TVector3.cxx
index ce0e2b2c676220afd1355be74b44e2f8efb9dd9b..f2104b5119398b14ddbf6449bf66b068a67addfc 100644
--- a/math/physics/src/TVector3.cxx
+++ b/math/physics/src/TVector3.cxx
@@ -168,6 +168,9 @@ theta plane) to the (x,y,z) frame.
 ClassImp(TVector3)
 
 //______________________________________________________________________________
+TVector3::TVector3()
+: fX(0.0), fY(0.0), fZ(0.0) {}
+
 TVector3::TVector3(const TVector3 & p) : TObject(p),
   fX(p.fX), fY(p.fY), fZ(p.fZ) {}