Adjoint Wilson lines and the effective gluon mass

The effective mass of the gluon is defined in terms of the energy stored in the string between adjoint sources. For SU(2) lattice gauge theory, I present Monte Carlo evidence that this mass scales correctly in the weak coupling regime and hence is non-zero and finite in the continuum limit. Various systematic errors (chief among them are temperature effects) still make it difficult to give a precise numerical value for this mass at zero temperature, but a range of 500 to 800 MeV seems reasonable (using a value for the string tension of (420 MeV)²). Some attempt is made to relate this quantity to a true “constituent gluon mass.”