Proton polarisabilities from Compton data using Covariant Chiral EFT

Abstract

We present a fit of the spin-independent electromagnetic polarisabilities of the proton to low-energy Compton scattering data in the framework of covariant baryon chiral effective field theory. Using the Baldin sum rule to constrain their sum, we obtain $\alpha =[10.6\pm 0.25$(stat)$\pm 0.2$(Baldin)$\pm 0.4$(theory)$]\times 10^{-4}$fm${}^3$ and $\beta =[3.2\mp 0.25$(stat)$\pm 0.2$(Baldin)$\mp 0.4$(theory)$]\times 10^{-4}$fm${}^3$, in excellent agreement with other chiral extractions of the same quantities.

Comments: 4 pages, 2 figures