Electric Polarizability of hadrons with nHYP-Clover fermions

Abstract

We present preliminary calculations for the electric polarizability of the neutral pion and neutron on three dynamically generated nHYP-Clover ensembles. We use two different pion masses (m π 300 and 220 MeV) to gauge the chiral behavior. The effects of partial quenching are analyzed by computing a string of partial quenched valence masses for each ensemble. We also analyzed the volume dependence using elongated lattices, where the elongation is in the direction of the electric field.

Compton scattering and nucleon polarisabilities in chiral EFT: The next steps

“…Error-bars at the physical point add statistical, theory and Baldin-sum-rule errors linearly, as applicable. Top: α E1 : (neutron) Lujan et al [27]; × (proton) and + (neutron) Detmold et al [28]; (neutron) Engelhardt/LHPC [29,30]. Bottom: β M1 : • (neutron) Hall et al [31]; (proton) and • (neutron) NPLQCD [26].…”

Polarisabilities of the proton and neutron from Compton scattering

“…In addition the magnetic polarisability β p M1 has been shown to be a crucial input in the determination of the two-photon-exchange contribution to the Lamb shift in muonic hydrogen [20,21,22,23], and the isovector β p M1 − β n M1 has been connected to the nucleon electromagnetic mass difference [25,24,26,27,28]. The calculation of nucleon polarisabilities is also an aim of lattice QCD, and several groups now have published results [29,30,31,32,33,34,35,36,37,38], albeit almost all at large pion masses. In this contribution we report on the results of high-precision EFT fits of scalar polarisabilities to current data, and on prospects for the determination of spin polarisabilities.…”