Leptoquark production in ultrahigh-energy neutrino interactions reexamined

The prospects for producing leptoquarks (LQs) in ultrahigh-energy (UHE) neutrino nucleon collisions are reexamined in the light of recent interpretations of DESY HERA data in terms of leptoquark production. We update predictions for cross sections for the production of first- and second-generation leptoquarks in UHE [Formula presented]-[Formula presented] and [Formula presented]-[Formula presented] collisions including (i) recent experimental limits on masses and couplings from the CERN LEP and Fermilab Tevatron colliders as well as rare processes, (ii) modern parton distributions, and (iii) radiative corrections to single leptoquark production. If the HERA events are due to an SU(2) doublet leptoquark that couples mainly to [Formula presented] states, we argue that there are likely other LQ states that couple to neutrinos that are close in mass, due to constraints from precision electroweak measurements.