Leading order relativistic hyperon-nucleon interactions in chiral effective field theory**Supported by the National Natural Science Foundation of China (11375024, 11522539, 11375120), the China Postdoctoral Science Foundation (2016M600845, 2017T100008) and the Fundamental Research Funds for the Central Universities

Abstract

We apply a recently proposed covariant power counting in nucleon-nucleon interactions to study strangeness S=−1 interactions in chiral effective field theory. At leading order, Lorentz invariance introduces 12 low energy constants, in contrast to the heavy baryon approach, where only five appear. The Kadyshevsky equation is adopted to resum the potential in order to account for the non-perturbative nature of hyperon-nucleon interactions. A fit to the 36 hyperon-nucleon scattering data points yields , which is comparable with the sophisticated phenomenological models and the next-to-leading order heavy baryon approach. However, one cannot achieve a simultaneous description of the nucleon-nucleon phase shifts and strangeness S=−1 hyperon-nucleon scattering data at leading order.