Strange nuclear matter from first-principles hadron scattering amplitudes

Descripción del proyecto

Las amplitudes de dispersión aportan información nueva sobre las estrellas de neutrones

Hay seis tipos de quarks, incluido los «extraños». Tres quarks unidos por la interacción nuclear fuerte forman bariones, un tipo de hadrón que incluye protones y neutrones. La interacción nuclear fuerte también une hadrones en núcleos. La presencia de quarks extraños altera las propiedades de los núcleos atómicos y la materia nuclear, lo que afecta a la masa y el radio de las estrellas de neutrones. Sin conocer los bariones que contienen quarks extraños (una subclase de bariones denominada «hiperón»), los científicos no pueden predecir cuantitativamente las masas y los radios de las estrellas de neutrones. El equipo del proyecto StrangeScatt, financiado por el Consejo Europeo de Investigación, pretende aportar información nueva sobre esta cuestión calculando amplitudes de dispersión de dos y tres hadrones entre nucleones (protones o neutrones) e hiperones directamente a partir de la teoría que describe las interacciones mediadas por la interacción nuclear fuerte.

Objetivo

StrangeScatt will assess the role of strange quarks in nuclear physics by performing first-principles computations of scattering amplitudes to study interactions between hadrons with strange quarks. The presence of strange quarks alters the properties of atomic nuclei and nuclear matter. For instance, the relationship between the mass and radius of neutron stars depends on the dynamics of strange quarks produced in their core. However, quantitative predictions of neutron star masses and radii are complicated by our ignorance of the fundamental interactions of baryons with strange quarks (hyperons). Such predictions are timely given the advent of dedicated neutron star observatories, multi-messenger astronomy, and earth-based experiments involving baryon resonances and nuclear matter.
Nuclear interactions are rooted in QCD, the fundamental force which binds quarks inside hadrons and hadrons inside nuclei. The bridge between few-body and many-body dynamics is made systematically with effective theories of the strong nuclear force, which require as input few-hadron scattering amplitudes as well as their quark-mass dependence. This project will compute two- and three-hadron scattering amplitudes between nucleons and hyperons directly from QCD using high-performance computer simulations on a space-time lattice.
Lattice QCD computations of scattering amplitudes have improved markedly thanks to algorithms developed by the PI, so that accurate and precise first-principles computations of are finally within reach. The unique ability of lattice computations to vary the up, down, and strange quark masses near their physical values is necessary for fully predictive effective theories. The PI's experience in lattice QCD computations of scattering amplitudes makes him ideally suited for StrangeScatt, which supports ground-based experiments and astrophysical observations by probing the role of strangeness in hadron interactions, nuclei, and nuclear matter.