Direct astrophysical tests of chiral effective field theory at supranuclear densities

Journal Article · Wed Nov 04 00:00:00 EST 2020 · Physical Review. C

DOI:https://doi.org/10.1103/physrevc.102.055803· OSTI ID:1756799

Essick, Reed ^[1]; Tews, Ingo  ^[2]; Landry, Philippe  ^[3]; Reddy, Sanjay ^[4]; Holz, Daniel E.  ^[5]

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1. Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP)
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
3. California State Univ., Fullerton, CA (United States)
4. Univ. of Washington, Seattle, WA (United States)
5. Univ. of Chicago, IL (United States). Kavli Inst. for Cosmological Physics (KICP); Univ. of Chicago, IL (United States). Enrico Fermi Inst.

Recent observations of neutron stars with gravitational waves and X-ray timing provide unprecedented access to the equation of state (EoS) of cold dense matter at densities difficult to realize in terrestrial experiments. At the same time, predictions for the EoS equipped with reliable uncertainty estimates from chiral effective field theory (_xEFT) allow us to bound our theoretical ignorance. In this work, we analyze astrophysical data using a nonparametric representation of the neutron-star EoS conditioned on _xEFT to directly constrain the underlying physical properties of the compact objects without introducing modeling systematics. We discuss how the data alone constrain the EoS at high densities when we condition on _xEFT at low densities. Here, we also demonstrate how to exploit astrophysical data to directly test the predictions of _xEFT for the EoS up to twice nuclear saturation density, in order to estimate the density at which these predictions might break down. We nd that the existence of massive pulsars, gravitational waves from GW170817, and NICER observations of PSR J0030+0451 favor _xEFT predictions for the EoS up to nuclear saturation density over a more agnostic analysis by as much as a factor of 7 for the quantum Monte Carlo (QMC) calculations used in this work. While _xEFT predictions using QMC are fully consistent with gravitational-wave data up to twice nuclear saturation density, NICER observations suggest that the EoS stiffens relative to these predictions at or slightly above nuclear saturation density. Additionally, for these QMC calculations, we marginalize over the uncertainty in the density at which _xEFT begins to break down, constraining the radius of a 1.4M_$$\bigodot$$ neutron star to R_1.4 = $$11.40^{+1.38}_{–1.04}$$ ($$12.54^{+0.71}_{–0.63}$$) km and the pressure at twice nuclear saturation density to p(2n_sat) = $$14.2^{+18.1}_{–8.4}$$ ($$28.7^{+15.3}_{–15.0}$$) MeV=fm³ with massive pulsar and gravitational-wave (and NICER) data.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC); National Science Foundation (NSF)
• Grant/Contract Number: 89233218CNA000001; AC52- 06NA25396; FG02-00ER41132; AC02- 05CH11231; PHY-0757058; PHY-0823459; PHY-1430152; PHY-1836734; PHY-1708081
• OSTI ID: 1756799
• Report Number(s): LA-UR-20-22615; TRN: US2205679
• Journal Information: Physical Review. C, Vol. 102, Issue 5; ISSN 2469-9985
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Atomic
Nuclear and Particle Physics