Abstract
Motivated by the bto ctau overline{v} anomalies, we study non-resonant searches for new physics at the large hadron collider (LHC) by considering final states with an energetic and hadronically decaying τ lepton, a b-jet and large missing transverse momentum left( ppto {tau}_hoverline{b}+{E}_{mathrm{T}}^{mathrm{miss}}right) . Such searches can be useful to probe new physics contributions to bto ctau overline{v} . They are analyzed not only within the dimension-six effective field theory (EFT) but also in explicit leptoquark (LQ) models with the LQ non-decoupled. The former is realized by taking a limit of large LQ mass in the latter. It is clarified that the LHC sensitivity is sensitive to the LQ mass for \U0001d4aa(1) TeV even in the search of ppto {tau}_hoverline{b}+{E}_{mathrm{T}}^{mathrm{miss}} . Although the LQ models provide a weaker sensitivity than the EFT limit, it is found that the non-resonant search of ppto {tau}_hoverline{b}+{E}_{mathrm{T}}^{mathrm{miss}} can improve the sensitivity by ≈ 40% versus a conventional mono-τ search left( ppto {tau}_h+{E}_{mathrm{T}}^{mathrm{miss}}right) in the whole LQ mass region. Consequently, it is expected that most of the parameter regions suggested by the bto ctau overline{v} anomalies can be probed at the HL-LHC. Also, it is shown that R2 LQ scenario is accessible entirely once the LHC Run 2 data are analyzed. In addition, we discuss a charge selection of τh to further suppress the standard-model background, and investigate the angular correlations among b, τ and the missing transverse momentum to discriminate the LQ scenarios.
Highlights
Background simulationAs for the SM background events generation, we basically trace the method explored in ref. [34]
Motivated by the b → cτ ν anomalies, we study non-resonant searches for new physics at the large hadron collider (LHC) by considering final states with an energetic and hadronically decaying τ lepton, a b-jet and large missing transverse momentum
Given the LQ mass MLQ, the high-pT search puts an upper bound on the LQ couplings and the Wilson coefficients (WCs) in eq (1.1) at the ΛLHC scale, which is encoded as CX (ΛLHC) in this paper
Summary
Leptoquark (LQ) models are employed as an illustrative realization of the WCs of the effective Hamiltonian in eq (1.1) They form the WCs at the NP scale Λ ∼ MLQ as. There are LQ models which contribute to multiple WCs. Given the LQ mass MLQ, the high-pT search puts an upper bound on the LQ couplings and the WCs in eq (1.1) at the ΛLHC scale, which is encoded as CX (ΛLHC) in this paper. These constraints are weakened by incorporating light vector-like leptons contributions via a GIM-like mechanism [44, 45] Another scenario has been discussed in the context of a U(2) flavor symmetry [46–53]. Assuming CV1 to be real, the result to explain the RD(∗) anomaly is given as φR ∼ 0.4π and CV1 ∼ 0.09 This scenario will be investigated in this paper.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
