SCALAR MESON TO PHOTON DECAY IN A LIGHT-FRONT CONSTITUENT QUARK MODEL

Abstract

The Standard Model predicts the existence of so-called exotic states such as glueballs,hybrids,and four-quark states. The presence of low lying exotics with J p c = Of+ complicates the analysis of the light scalar mesons since, given the fact that they have the same quantum numbers, they will tend to mix. Here, we present a calculation of the fo + yy transition form factor for the isoscalar states fo(1370), fo(lSOO), and fo( 1710) using a light-front constituent quark model. The flavor-glue content of these states is determined using a mass-squared mixing scheme. The form factor calculation involves writing down a light-cone spin-space wavefunction for the scalar meson. The radial wavefunction is taken to be a simple harmonic oscillator wavefunction with one model parameter, which is then used as a trial wavefunction of the variational method. The spin-orbit wavefunction is determined exactly by the Melosh transformation. The full wavefunction is then used to calculate the two-photon transition form factor. In the limit as q2 goes to zero, the form factor can be used to calculate the fo + yy decay width. Ratios of these decay widths for the different scalars can be compared with other model calculations.