Chiral behavior of the rho meson in lattice QCD - art. no. 094502

In order to guide the extrapolation of the mass of the rho meson calculated in lattice QCD with dynamical fermions, we study the contributions to its self-energy, which vary most rapidly as the quark mass approaches zero. fro m the processes p --> omega pi and rho-->pi pi. It turns out that in analyz ing the most recent data from the CP-PACS Collaboration, it is crucial to e stimate the self-energy from rho-->pi pi using the same grid of discrete mo menta as included implicitly in the lattice simulation. The correction asso ciated with the continuum infinite volume limit can then be found by calcul ating the corresponding integrals exactly. Our error analysis suggests that a factor of 10 improvement in statistics at the lowest quark mass for whic h data currently exists would allow one to determine the physical rho mass to within 5%. Finally, our analysis throws light on a longstanding problem with the J parameter.