Search for tZ′ associated production induced by tcZ′ couplings at the LHC
AbstractThe P5′ and RK anomalies, recently observed by the LHCb Collaboration in B→K(*) transitions, may indicate the existence of a new Z′ boson, which may arise from gauged Lμ-Lτ symmetry. Flavor-changing neutral current Z′ couplings, such as tcZ′, can be induced by the presence of extra vector-like quarks. In this paper we study the LHC signatures of the induced right-handed tcZ′ coupling that is inspired by, but not directly linked to, the B→K(*) anomalies. The specific processes studied are cg→tZ′ and its conjugate process, each followed by Z′→μ+μ-. By constructing an effective theory for the tcZ′ coupling, we first explore in a model-independent way the discovery potential of such a Z′ at the 14 TeV LHC with 300 and 3000 fb-1 integrated luminosities. We then reinterpret the model-independent results within the gauged Lμ-Lτ model. In connection with tcZ′, the model also implies the existence of a flavor-conserving ccZ′ coupling, which can drive the cc¯→Z′→μ+μ- process. Our study shows that existing LHC results for dimuon resonance searches already constrain the ccZ′ coupling, and that the Z′ can be discovered in either or both of the cg→tZ′ and cc¯→Z′ processes. We further discuss the sensitivity to the left-handed tcZ′ coupling and find that the coupling values favored by the B→K(*) anomalies lie slightly below the LHC discovery reach even with 3000 fb-1.