Low-energy interactions of scalar and pseudoscalar Higgs bosons with baryons

It is pointed out that a fit to the baryon-octet mass spectrum to the first order of SU(3) breaking indicates unambiguously a substantial sea-quark content in the baryon at rest. Owing to the presence of sizeable strange quark-antiquark pairs in the nucleon as implied by the pion-nucleon sigma term, the effective low-energy scalar Higgs-nucleon coupling gΦNN ≅ 2.2x10-3 is dominated by strange quarks rather than by heavy quarks. The couplings gΦΣΣ and gΦΞΞ are estimated to be 3.2x10-3 and 3.7x10-3, respectively. Supplemented by the 1/Nc expansion (Nc being the number of colors) and by the recent EMC measurement on the proton polarized structure functions, the coupling of the pseudoscalar Higgs boson to nucleons is fixed. A discussion of axion couplings is given. (orig.)