Hyperon puzzle: Hints from quantum monte carlo calculations

The onset of hyperons in the core of neutron stars and the consequent softening of the equationof state have been questioned for a long time. Controversial theoretical predictions and the recentastrophysical observations are the grounds for the so-calledhyperon puzzle. We calculate the equationof state and the mass-radius relation of an infinite systems of neutrons andΛparticles by usingthe auxiliary field diffusion Monte Carlo algorithm. We find that the three-body hyperon-nucleoninteraction plays a fundamental role in the softening of the equation of state and for the consequentreduction of the predicted maximum mass. We have considered two different models of three-body force that successfully describe the binding energy of medium mass hypernuclei. Our resultsindicate that they give dramatically different results on the maximum mass of neutron stars, notnecessarily incompatible with the recent observation of very massive neutron stars. We concludethat stronger constraints on the hyperon-neutron force are necessary in order to properly assess therole of hyperons in neutron stars.