String breaking as a mixing phenomenon in the SU(2) Higgs model

We study the potential of a static quark anti-quark pair in the confinement ''phase'' of the SU(2) Higgs model. Around separation r_b, the confining string of the gauge field breaks by formation of a dynamical pair of light quarks. The ground state and first excited state static potentials are determined by a variational technique from a matrix correlation in which suitably smeared gauge and Higgs fields enter. Our results at #beta# = 2.4 clearly show string breaking (r_b #approx# 1.9r_0). The investigation of properly defined overlaps confirms the interpretation of string breaking as a level crossing phenomenon between string-type and meson-type states. We study the scaling properties of the static potentials along a line of constant physics, varying the lattice spacing by a factor of 2. Our results show compatibility with scaling within tiny errors. (orig.)46 refs.SIGLEAvailable from TIB Hannover: RA 2999(00-78) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman