Magnetic polarizability of hadrons from lattice QCD in the background field method

Abstract

We present a calculation of hadron magnetic polarizability using the techniques of lattice QCD. This is carried out by introducing a uniform external magnetic field on the lattice and measuring the quadratic part of a hadron's mass shift. The calculation is performed on a $24^4$ lattice with standard Wilson actions at beta=6.0 (spacing $a=0.1$ fm) and pion mass down to about 500 MeV. Results are obtained for 30 particles covering the entire baryon octet ($n$, $p$, ${\Sigma }^0$, ${\Sigma }^{-}$, ${\Sigma }^{+}$, ${\Xi }^{-}$, ${\Xi }^0$, $\Lambda$) and decuplet (${\Delta }^0$, ${\Delta }^{-}$, ${\Delta }^{+}$, ${\Delta }^{++}$, ${\Sigma }^{\ast 0}$, ${\Sigma }^{\ast -}$, ${\Sigma }^{\ast +}$, ${\Xi }^{\ast 0}$, ${\Xi }^{\ast -}$, ${\Omega }^{-}$), plus selected mesons (${\pi }^0$, ${\pi }^{+}$, ${\pi }^{-}$, $K^0$, $K^{+}$, $K^{-}$, ${\rho }^0$, ${\rho }^{+}$, ${\rho }^{-}$, $K^{\ast 0}$, $K^{\ast +}$, $K^{\ast -}$). The results are compared with available values from experiments and other theoretical calculations.

Comments: 30 pages, 23 figures, 5 tables