Electric Polarizability of Neutral Hadrons from Lattice QCD

Abstract

By simulating a uniform electric field on a lattice and measuring the change in the rest mass, we calculate the electric polarizability of neutral mesons and baryons using the methods of quenched lattice QCD. Specifically, we measure the electric polarizability coefficient from the quadratic response to the electric field for 10 particles: the vector mesons ${\rho }^0$ and $K^{\ast 0}$; the octet baryons n, ${\Sigma }^0$, ${\Lambda }_o^0$, ${\Lambda }_s^0$, and ${\Xi }^0$; and the decouplet baryons ${\Delta }^0$, ${\Sigma }^{\ast 0}$, and ${\Xi }^{\ast 0}$. Independent calculations using two fermion actions were done for consistency and comparison purposes. One calculation uses Wilson fermions with a lattice spacing of $a=0.10$fm. The other uses tadpole improved Lüsher-Weiss gauge fields and clover quark action with a lattice spacing $a=0.17$fm. Our results for neutron electric polarizability are compared to experiment.

Comments: 25 pages, 20 figures