Testing leptoquark models in (B)over-bar → D τν

We study potential new physics effects in the (B) over barB -> D tau nu decays. As a particular example of new physics models, we consider the class of leptoquark models and put the constraints on the leptoquark couplings using the recently measured ratios R(D) = B (B) over bar -> D tau nu)/B((B) over bar -> D mu nu). For consistency, some of the constraints are compared with the ones coming from the current experimental bound on B(B -> X-s nu nu). In order to discriminate various new physics scenarios, we examine the correlations between different observables that can be measured in the future.