diff --git a/Config/Constants.h b/Config/Constants.h
--- a/Config/Constants.h
+++ b/Config/Constants.h
@@ -1,71 +1,86 @@
 // -*- C++ -*-
 //
 // Constants.h is a part of ThePEG - Toolkit for HEP Event Generation
 // Copyright (C) 1999-2011 Leif Lonnblad
 //
 // ThePEG is licenced under version 2 of the GPL, see COPYING for details.
 // Please respect the MCnet academic guidelines, see GUIDELINES for details.
 //
 #ifndef ThePEG_Constants_H
 #define ThePEG_Constants_H
 
 // This file defines a number of useful constants, placed in the
 // namespace <!id>ThePEG::Constants<!!id>.
 
 #include "Unitsystem.h"
 #include <cmath>
 #include <cfloat>
 
 namespace ThePEG {
 
 /**
  * The Constants namespace containing some useful physical constants
  * with suitable units.
  */
 namespace Constants {
 
 using namespace ThePEG::Units;
 
 /** A really large length. */
 const Length MaxLength = 1.0e20 * meter;
 
 /** A really large energy. */
 const Energy MaxEnergy = 1.0e6 * GeV;
 
 /** A really large squared energy. */
 const Energy2 MaxEnergy2 = MaxEnergy * MaxEnergy;
 
 /** The largest possible double. */
 const double MaxDouble = DBL_MAX;
 
 /** A really large double. */
 const double HugeDouble = DBL_MAX * 1.0e-4;
 
 /** The largest possible float. */
 const double MaxFloat = FLT_MAX;
 
 /** A really large floa.t */
 const double HugeFloat = FLT_MAX * 0.01;
 
 /** A really large rapidity */
 const double MaxRapidity = 100.0;
 
 /** Good old \f$\pi\f$. */
 const double pi    = M_PI;
 
 /** Good old \f$2\pi\f$. */
 const double twopi = 2.0 * pi;
 
 /** A really large integer */
 const long MaxInt = 1000000000L;
 
 /** The smallest non-zero double. */
 const double epsilon = DBL_EPSILON;
 
 /** The Euler gamma */
 const double EulerGamma = 0.5772156649015329;
+
+/** \f$\zeta(2)\f$. */
+const double zeta2 = pi*pi/6.;
+
+/** \f$\zeta(3)\f$. */
+const double zeta3 = 1.2020569031595943;
+
+/** \f$\zeta(4)\f$. */
+const double zeta4 = 0.4*zeta2*zeta2;
+
+/** \f$\zeta(5)\f$. */
+const double zeta5 = 1.0369277551433699;
+
+/** \f$\zeta(6)\f$. */
+const double zeta6 = 4.*zeta2*zeta4/7.;
 }
 
 }
 
 #endif /* ThePEG_Constants_H */