Bounds on antineutrinos and sterile neutrinos from SNO and SuperKamiokande data

The data from SNO and SuperKamiokande are used to derive upper bounds on antineutrinos ν¯X and sterile neutrinos νS which may accompany the LMA effect. We consider separately LMA+ν¯X, LMA+νS and the general case LMA+ν¯X+νS. We obtain for LMA+ν¯X upper and lower bounds on fB the SSM normalization factor. For LMA+νS we recover the νS upper bound existing in the literature. In the general case it is seen that the upper bound on νS is hardly sensitive to the ν¯X component. We conclude with a simple χ2 analysis of all four cases considered.