Lattice Charge Overlap I. Elastic Limit of Pi and Rho Mesons
✍ Scribed by William Andersen; Walter Wilcox
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 429 KB
- Volume
- 255
- Category
- Article
- ISSN
- 0003-4916
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✦ Synopsis
Using lattice quantum chromodynamics on a 16 3 _24 lattice at ;=6.0, we examine the elastic limit of charge overlap functions in the quenched approximation for the pion and rho mesons; results are compared to previous direct current insertion calculations. A good signal is seen for the pion, but the electric and magnetic rho meson results are considerably noisier. We find that the pion and rho results are characterized by a monopole mass to rho mass ratio of 0.97(8) and 0.73(10), respectively. Assuming that the functional forms of the electric and magnetic form factors are the same, we also find a rho meson g-factor of g=2.25(34), consistent with the nonrelativistic quark model. 1997 Academic Press I. INTRODUCTION Charge overlap techniques are based upon the direct construction of four-point functions on the lattice, representing zero momentum hadronic charge or current overlap matrix elements, (h(0) | J + (x) J & (0) | h( 0)). These amplitudes are the primitive building blocks for many experimental quantities of interest in strong interaction physics, from elastic and zero momentum properties like form factors and magnetic moments, to inelastic properties (from a hadron point of view) like structure functions and electric and magnetic polarizability coefficients. However, it is apparent that evaluation of four-point functions on the lattice can be problematical because of computer limitations. For example, it is necessary to have a long enough time axis in order to separate the fixed hadron creation and annihilation fields sufficiently to avoid lattice artifacts. On the other hand, these methods possess great versatility since many different observables can be measured with the same set of calculated quark propagators. It is therefore of interest to implement a study of these lattice correlation functions, comparing them, where possible, to previous results using two and three-point functions. We are initiating such a study in the article no.