A bound on the nucleon Druck-term from chiral EFT in curved space-time and mechanical stability conditions
J. Gegelia, Maxim V. Polyakov
Abstract
Using dispersive representations of the nucleon gravitational form factors, the results for their absorptive parts from chiral effective field theory in curved space-time, and the mechanical stability conditions, we obtain a model independent inequality for the value of the gravitational D ( t ) form factor at zero momentum transfer (Druck-term). In particular, the obtained inequality leads to a conservative bound on the Druck-term in the chiral limit D ≤ − 0.95 ( 9 ) . This bound implies the restriction on the low-energy constant c 8 of the effective chiral action for nucleons and pions in the presence of an external gravitational field , c 8 ≤ − 1.1 ( 1 ) GeV −1 . For the physical pion mass we obtain a model independent bound D ≤ − 0.20 ( 2 ) .