Abstract
The discovery of nondiffuse sources of gravitational waves through compact-object mergers opens new prospects for the study of physics beyond the Standard Model. In this paper, we study the effects of a new force between quarks, suggested by the gauging of baryon number, on pure neutron matter at supranuclear densities. This leads to a stiffening of the equation of state, allowing neutron stars to be both larger and heavier and possibly accommodating the light progenitor of GW190814 as a neutron star. The role of conventional three-body forces in neutron star structure is still poorly understood, though they can act in a similar way, implying that the mass and radius do not in themselves resolve whether new physics is coming into play. However, a crucial feature of the scenario we propose is that the regions of the new physics parameter space that induce observable changes to neutron star structure are testable at low-energy accelerator facilities. This testability distinguishes our scenario from other classes of new phenomena in dense matter.
Highlights
The environment of a proto-neutron star (NS) has long been known to be exquisitely sensitive to the appearance of new physics (NP), manifested through light particles such as axions [1,2,3,4,5,6,7] or dark photons [8,9,10], through cooling effects
Where N is the nucleon doublet, i is a charged lepton, and ε, crudely ≈ egB/(4π )2, can be made smaller still [71], with ε ∼ 10−8–10−2 [72]. Experimental constraints are such that the new mediator cannot be too light [64,70]; we focus on gauge mediators of about 0.2–1 GeV in mass, for which gB can be as large as gB ≈ 0.4 [65,70,73]
We have considered how a new force between firstgeneration quarks can make NSs for a fixed equation of state (EoS) and many-body method both heavier and puffier
Summary
The environment of a proto-neutron star (NS) has long been known to be exquisitely sensitive to the appearance of new physics (NP), manifested through light particles such as axions [1,2,3,4,5,6,7] or dark photons [8,9,10], through cooling effects. Its contribution to the nucleon-nucleon (NN) force can be hidden within the short-distance repulsion of the phenomenological NN force in the SM, recalling, e.g., the repulsive hard core of the Reid potential at separations of rhc = 0.5 fm [29], yet it can modify the the neutron matter equation of state (EoS) at supranuclear densities, i.e., beyond the saturation number density of ordinary nuclear matter, nsat [30] We expect these models to be accompanied by electromagnetic signatures, such as, e.g., brighter kilonovas, due to X -γ mixing, but reserve this for later work [31]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
