LHC constraints and prospects for S1 scalar leptoquark explaining the (B)over-bar → D(*) τ(ν)over-bar anomaly

Recently, deviations in flavor observables of (B) over bar -> D-(*)tau(nu) over bar have been shown between the predictions in the Standard Model and the experimental results reported by BABAR, Belle, and LHCb collaborations. One of the solutions to this anomaly is obtained in a class of leptoquark model with a scalar leptoquark boson S-1, which is a SU(3)(c) triplet and SU(2)(L) singlet particle with -1/3 hypercharge interacting with a quark-lepton pair. With well-adjusted couplings, this model can explain the anomaly and be compatible with all flavor constraints. In such a case, the S-1 boson can be pair-produced at CERN's Large Hadron Collider (LHC) and subsequently decay as S-1* -> t tau, b nu, and c tau. This paper explores the current 8 and 13 TeV constraints, as well as the detailed prospects at 14 TeV, of this flavor-motivated S-1 model. From the current available 8 and 13 TeV LHC searches, we obtain constraints on the S-1 boson mass for M-S1 < 400-640 GeV depending on values of the leptoquark couplings to fermions. Then we study future prospects for this scenario at the 14 TeV LHC using detailed cut analyses and evaluate exclusion and discovery potentials for the flavor- motivated S-1 leptoquark model from searches for the (b nu) (<(b)over bar>(nu) over bar) and (c tau) ((c) over bar(tau) over bar) final states. In the latter case, we consider several scenarios for the identification of charm jets. As a result, we find that the S-1 leptoquark origin of the (B) over bar -> D-(*) tau(nu) over bar anomaly can be probed with M-S1 less than or similar to 600/800 GeV at the 14 TeV LHC with L = 300/3000 fb(-1) of accumulated data. One can also see that the 14 TeV LHC run II with L = 300 fb(-1) can exclude the S-1 leptoquark boson up to M-S1 similar to 0.8 TeV at 95% confidence level, whereas a future 14 TeV LHC with L = 3000 fb(-1) data has a potential to discover the S-1 leptoquark boson with its mass up to M-S1 similar to 1.1 TeV with over 5 sigma significance, from the (b nu) ((b) over bar(nu) over bar) and/or (c tau) ((c) over bar(tau) over bar) searches.