[Jlab-seminars] Today's Physics Seminar: Farrooh Fattoyev; Connecting Neutron Skins to Gravitational Waves

[Stephanie Tysor]

Physics Seminar 

Farrooh Fattoyev 

Indiana University, Bloomington 



Connecting Neutron Skins to Gravitational Waves 



Abstract : 



The historical first detection of a binary neutron star (BNS) merger by the LIGO-Virgo collaboration is providing fundamental new insights into the nature of dense neutron-rich nuclear matter. By using a set of realistic models of the equation of state (EOS) that yield an accurate description of the properties of finite nuclei, support neutron stars of two solar masses, and provide a Lorentz covariant extrapolation to dense matter we confront their predictions against the measured tidal deformability from the BNS merger. These models also predict a range of neutron skin thicknesses in Pb-208 that is consistent with the lower-to-central values of the first model-independent measurement of the neutron skin by the PREX Collaboration, i.e. 0.15 fm ≤ R_skin ≤ 0.33 fm. Since the gravitational-wave signal is sensitive to the underlying EOS, limits on the tidal deformability inferred from the observation translate into constraints on the neutron-star radius. In particular, we find an upper limit on the radius of a 1.4 solar-mass neutron star of R < 13.76 km. And given the sensitivity of the neutron-skin thickness of Pb-208 to the density dependence of the symmetry energy, hence to the neutron star radii, we infer a corresponding upper limit on the neutron skin of about R_skin ≲ 0.25 fm. If the upcoming PREX-II (or CREX) experiment measures a significantly thicker skin in Pb-208 (or in Ca-48 as predicted by the same models), this may be evidence of a softening of the symmetry energy at high densities – likely indicative of a phase transition in the interior of neutron stars. 



Wednesday January 24, 2018 

11:00am 

CEBAF F113 

-- 
Stephanie Tysor 
Hall A Administrative Assistant 
Thomas Jefferson National Accelerator Facility 
(office)757-269-6005 (fax)757-269-5235 
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