Maximal neutron star mass and the resolution of the hyperon puzzle in modified gravity

Abstract

The so-called "hyperonization puzzle" in the theory of neutron stars is considered in the framework of modified f (R) gravity. We show that for simple hyperon equations of state, it is possible to obtain the maximal neutron star mass which satisfies the recent observational data for PSR J1614-2230, in higher-derivative models with power-law terms as f (R) = R+γR 2 +βR 3 . The soft hyperon equation of state under consideration is usually treated as non-realistic in the standard General Relativity. The numerical analysis of Mass-Radius relation for massive neutron stars with hyperon equation of state in modified gravity turns out to be consistent with observations. Thus, we show that the same modified gravity can solve at once three problems: consistent description of the maximal mass of neutron star, realistic Mass-Radius relation and account for hyperons in equation of state.

Accelerating cosmologies and the phase structure ofF(R)gravity with Lagrange multiplier constraints: A mimetic approach

“…This model has quite appealing phenomenological features, since as was shown in Ref. [24], when this model is employed to neutron stars, it generates an increase in the maximal neutron star mass, which is a very interesting phenomenological feature. Our purpose is to find which mimetic scalar potential V (φ = t) and Lagrange multiplier generates a cosmological evolution compatible with observations, for the F (R) gravity of Eq.…”

Dilatonic equation of hydrostatic equilibrium and neutron star structure

“…4), while for a neutron star, with increasing radius, the mass decreases, (see Ref. (Astashenok 2014) for more details). In other words, there are critical values for Λ and α, so that, the diagram related to gravitational mass versus radius is not similar to the diagram related to ordinary neutron star.…”

Constraining gravity with hadron physics: neutron stars, modified gravity and gravitational waves

“…What I and others guess is that, just as the 3-body force is repulsive, higher terms in the EFT-EOS must also make it stiffer, to later soften into something phenomenologically viable when other degrees of freedom activate. Of course, another logical possibility is to have doubly exotic physics: new gravity phenomena (such as f (R) corrections to the Einstein-Hilbert action) providing the margin for the EOS to actually be softer [54].…”