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 ($n$, $p$, $Σ^0$, $Σ^-$, $Σ^+$, $Ξ^-$, $Ξ^0$, $Λ$) and decuplet ($Δ^0$, $Δ^-$, $Δ^+$, $Δ^{++}$, $Σ^{*0}$, $Σ^{*-}$, $Σ^{*+}$, $Ξ^{*0}$, $Ξ^{*-}$, $Ω^-$), plus selected mesons ($π^0$, $π^+$, $π^-$, $K^0$, $K^+$, ${K}^-$, $ρ^0$, $ρ^+$, $ρ^-$, $K^{*0}$, $K^{*+}$, $K^{*-}$). The results are compared with available values from experiments and other theoretical calculations.