Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userConstraining three-nucleon forces with multimessenger data
77
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We report the results of a study aimed at inferring direct information on the repulsive three-nucleon potential $V^R_{ijk}$textemdash driving the stiffness of the nuclear matter equation of state at supranuclear densitiestextemdash from astrophysical observations. Using a Bayesian approach, we exploit the measurements of masses, radii and tidal deformabalities performed by the NICER satellite and the LIGO/Virgo collaboration, as well as the mass of the heaviest observed pulsar, to constrain the strength of $V^R_{ijk}$. The baseline of our analysis is the widely employed nuclear Hamiltonian comprising the Argonne $v_{18}$ nucleon-nucleon potential andthe Urbana IX model of three-nucleon potential. The numerical results, largely determined by the bound on the maximum mass, suggest that existing and future facilities have the potential to provide valuable new insight into microscopic nuclear dynamics at supranuclear densities.
rate research
Read More
The equation of state (EoS) of the neutron star (NS) matter remains an enigma. In this work we perform the Bayesian parameter inference with the gravitational wave data (GW170817) and mass-radius observations of some NSs (PSR J0030+0451, PSR J0437-4715, and 4U 1702-429) using the phenomenologically constructed EoS models to search for a potential first-order phase transition. Our phenomenological EoS models take the advantages of current widely used parametrizing methods, which are flexible enough to resemble various theoretical EoS models. We find that the current observation data are still not informative enough to support/rule out phase transition, due to the comparable evidences for models with and without phase transition. However, the bulk properties of the canonical $1.4,M_odot$ NS and the pressure at around $2rho_{rm sat}$ are well constrained by the data, where $rho_{rm sat}$ is the nuclear saturation density. Moreover, strong phase transition at low densities is disfavored, and the $1sigma$ lower bound of transition density is constrained to $1.84rho_{rm sat}$.
We show how observations of gravitational waves from binary neutron star (BNS) mergers over the next few years can be combined with insights from nuclear physics to obtain useful constraints on the equation of state (EoS) of dense matter, in particular, constraining the neutron-matter EoS to within 20% between one and two times the nuclear saturation density $n_0approx 0.16 {text{fm}^{-3}}$. Using Fisher information methods, we combine observational constraints from simulated BNS merger events drawn from various population models with independent measurements of the neutron star radii expected from x-ray astronomy (the Neutron Star Interior Composition Explorer (NICER) observations in particular) to directly constrain nuclear physics parameters. To parameterize the nuclear EoS, we use a different approach, expanding from pure nuclear matter rather than from symmetric nuclear matter to make use of recent quantum Monte Carlo (QMC) calculations. This method eschews the need to invoke the so-called parabolic approximation to extrapolate from symmetric nuclear matter, allowing us to directly constrain the neutron-matter EoS. Using a principal component analysis, we identify the combination of parameters most tightly constrained by observational data. We discuss sensitivity to various effects such as different component masses through population-model sensitivity, phase transitions in the core EoS, and large deviations from the central parameter values.
We introduce a family of equations of state (EoS) for hybrid neutron star (NS) matter that is obtained by a two-zone parabolic interpolation between a soft hadronic EoS at low densities and a set of stiff quark matter EoS at high densities within a finite region of chemical potentials $mu_H < mu < mu_Q$. Fixing the hadronic EoS as the APR one and chosing the color-superconductiong, nonlocal NJL model with two free parameters for the quark phase, we perform Bayesian analyses with this two-parameter family of hybrid EoS. Using three different sets of observational constraints that include the mass of PSR J0740+6620, the tidal deformability for GW170817 and the mass-radius relation for PSR J0030+0451 from NICER as obligatory (set 1), while set 2 uses the possible upper limit on the maximum mass from GW170817 as additional constraint and set 3 instead the possibility that the lighter object in the asymmetric binary merger GW190814 is a neutron star. We confirm that in any case the quark matter phase has to be color superconducting with the dimensionless diquark coupling approximately fulfilling the Fierz relation $eta_D=0.75$ and the most probable solutions exhibiting a proportionality between $eta_D$ and $eta_V$, the coupling of the repulsive vector interaction that is required for a sufficiently large maximum mass. We anticipate the outcome of the NICER radius measurement on PSR J0740+6220 as a fictitious constraint and find evidence for claiming that GW190814 was a binary black hole merger if the radius will be 11 km or less.
Many of the astrophysical sources and violent phenomena observed in our Universe are potential emitters of gravitational waves (GW) and high-energy neutrinos (HEN). Both GWs and HENs may escape very dense media and travel unaffected over cosmological distances, carrying information from the innermost regions of the astrophysical engines. Such messengers could also reveal new, hidden sources that have not been observed by conventional photon-based astronomy. Coincident observation of GWs and HENs may thus play a critical role in multimessenger astronomy. This is particularly true at the present time owing to the advent of a new generation of dedicated detectors: IceCube, ANTARES, VIRGO and LIGO. Given the complexity of the instruments, a successful joint analysis of this data set will be possible only if the expertise and knowledge of the data is shared between the two communities. This review aims at providing an overview of both theoretical and experimental state-of-the-art and perspectives for such a GW+HEN multimessenger astronomy.
Three-nucleon forces (3NF) are investigated from two-flavor lattice QCD simulations. We utilize the Nambu-Bethe-Salpeter (NBS) wave function to determine two-nucleon forces (2NF) and 3NF in the same framework. As a first exploratory study, we extract 3NF in which three nucleons are aligned linearly with an equal spacing. This is the simplest geometrical configuration which reduces the huge computational cost of calculating the NBS wave function. Quantum numbers of the three-nucleon system are chosen to be (I, J^P)=(1/2,1/2^+) (the triton channel). Lattice QCD simulations are performed using N_f=2 dynamical clover fermion configurations at the lattice spacing of a = 0.156 fm on a 16^3 x 32 lattice with a large quark mass corresponding to m_pi= 1.13 GeV. We find repulsive 3NF at short distance in the triton channel. Several sources of systematic errors are also discussed.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
