Muon (g − 2) and flavor puzzles in the U(1)X-gauged leptoquark model

Abstract

We present an economical model where an S1 leptoquark and an anomaly-free U(1)X gauge symmetry with X = B3− 2Lμ/3 − Lτ/3 are introduced, to account for the muon anomalous magnetic moment aμ≡ (gμ− 2) and flavor puzzles including $$ {R}_{K^{\left(\ast \right)}} $$ R K ∗ and $$ {R}_{D^{\left(\ast \right)}} $$ R D ∗ anomalies together with quark and lepton flavor mixing. The Z′ gauge boson associated with the U(1)X symmetry is responsible for the $$ {R}_{K^{\left(\ast \right)}} $$ R K ∗ anomaly. Meanwhile, the specific flavor mixing patterns of quarks and leptons can be generated after the spontaneous breakdown of the U(1)X gauge symmetry via the Froggatt-Nielsen mechanism. The S1 leptoquark which is also charged under the U(1)X gauge symmetry can simultaneously explain the latest muon (g − 2) result and the $$ {R}_{D^{\left(\ast \right)}} $$ R D ∗ anomaly. In addition, we also discuss several other experimental constraints on our model.

Analysis of P cs (4338) and related pentaquark molecular states via QCD sum rules*

“…[2, 52], the n f is the flavor number, it is set as n f = 4 and n f = 5 for the doubly-charm and doubly-bottom pentaquark molecular states, respectively, the corresponding Λ QCD which depends on n f are 296 MeV and 213 MeV, respectively. The energy scale formula is applied to determine the best energy scales of the QCD spectral densities [53,54,55,56],…”