Testing the R_{D^{(*)}} anomaly at the LHeC

Abstract

B-Physics anomalies have recently raised renewed interest in leptoquarks, predicted in several theoretical frameworks. Under simplifying but conservative assumptions, we show that the current limits from LHC searches together with the requirement to explain the observed value for R_{D^{(*)}} constrain the R_2 leptoquark mass to be in the range of 800 le m_{R_2} le 1000 GeV. We study the search for R_2 at the LHeC via its resonance in the btau final state by performing a cut-and-count analysis of the signal and the dominant Standard Model backgrounds. We find that the LHeC has an excellent discovery potential for the R_2 leptoquark even for couplings to the first generation as small as {mathcal {O}}(10^{-2}).