High statistics analysis using anisotropic clover lattices: III. Baryon-baryon interactions


Low-energy baryon-baryon interactions are calculated in a high-statistics lattice QCD study on a single ensemble of anisotropic-clover gauge-field configurations at a pion mass of m(pi) similar to 390 MeV, a spatial volume of L(3) similar to (2.5 fm)(3), and a spatial lattice spacing of b similar to 0.123 fm. Luscher's method is used to extract nucleon-nucleon, hyperon-nucleon, and hyperon-hyperon scattering phase shifts at one momentum from the one-and two-baryon ground-state energies in the lattice volume. The isospin-3= 2 N Sigma interactions are found to be highly spin dependent, and the interaction in the (3)S(1) channel is found to be strong. In contrast, the N Lambda interactions are found to be spin independent, within the uncertainties of the calculation, consistent with the absence of one-pion exchange. The only channel for which a negative energy shift is found is Lambda Lambda, indicating that the Lambda Lambda interaction is attractive, as anticipated from modeldependent discussions regarding the H dibaryon. The nucleon-nucleon (NN) scattering lengths are found to be small, clearly indicating the absence of any fine-tuning in the NN sector at this pion mass. This is consistent with our previous lattice QCD calculation of NN interactions. The behavior of the signal-to-noise ratio in the baryon-baryon correlation functions, and in the ratio of correlation functions that yields the ground-state energy splitting is explored. In particular, focus is placed on the window of time slices for which the signal-to-noise ratio does not degrade exponentially, as this provides the opportunity to extract quantitative information about multibaryon systems.



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Physical Review D



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