The fate of $$\mathbf{V}_\mathbf{1}$$ vector leptoquarks: the impact of future flavour data

Abstract

Motivated by the recent experimental progress on the B-meson decay anomalies (in particular the angular observables in $$B\rightarrow K^*\mu \mu $$ B → K ∗ μ μ ), we rely on a simplified-model approach to study the prospects of vector leptoquarks in what concerns numerous flavour observables, identifying several promising decay modes which would allow to (indirectly) probe such an extension. Our findings suggest that the confirmation of the B-meson decay anomalies, in parallel with positive signals (at Belle II or LHCb) for $$\tau \rightarrow \phi \mu $$ τ → ϕ μ , $$B_{(s)}$$ B ( s ) -meson decays to $$\tau ^+ \tau ^-$$ τ + τ - and $$\tau ^+ \mu ^-$$ τ + μ - ($$\tau ^+ e^-$$ τ + e - ) final states, as well as an observation of certain charged lepton flavour violation decays (at COMET or Mu2e), would contribute to strengthen the case for this scenario. We also illustrate how the evolution of the experimental determination of $$R_{D^{(*)}}$$ R D ( ∗ ) could be instrumental in falsifying an explanation of the anomalous B-meson decay data via a vector $$V_1$$ V 1 leptoquark.

Atomki anomaly in gauged $U(1)_R$ symmetric model

“…1, the coupling constant of neutrinos is much smaller than 10 −5 for small Q. Therefore, our result is consistent with that of [20].…”

“…Unless Q is very close to zero, the constraint excludes R > ∼ 10 −8 /Q. 5 Recently, in [20], this constraint is computed using data and χ 2 fit is performed. As we have shown in Fig.…”

“…Vector boson hypothesis was firstly studied in [9,10] in a gauged B − L symmetric model, taking various experimental constraints into account. Then, many models have been proposed in contexts of an extra U(1) gauge symmetry [11][12][13], dark matter [14][15][16], neutrino physics [17], lepton anomalous magnetic moments [18][19][20] and others [21][22][23][24][25]. Experimental searches of the X boson are also studied in [26][27][28][29].…”

A New Charged Lepton Flavor Violation Program at Fermilab

“…In scenarios dominated by the contribution of penguin diagrams, such as many supersymmetric setups [16] or the scotogenic model [19], µ + → e + γ rates can be several orders of magnitude larger than those of µ + → e + e − e + decays and µ − − e − conversion. Alternatively, tree level interactions, including leptoquarks [20,21] and Z models [22], are best probed with µ + → e + e − e + decays and µ − − e − conversion as µ + → e + γ rates are (strongly) suppressed.…”

Muon physics: from phenomenology to experiment

“…As an illustrative example, we have considered a SM extension via a single vector leptoquark, and 3 generations of vector-like heavy leptons. Similar to the case of additional sterile neutrinos, which leads to non-unitary left-handed leptonic mixings, the mixings of the charged leptons with the heavy vector-like fermions lead to a departure from unitarity, and hence to modified leptoquark-quark-lepton interactions, which in turn successfully allows to address both R K ( * ) and R D ( * ) [30]. The model is severely constrained by electroweak precision observables and from cLFV bounds (in particular from K → eµ decays and µ − e conversion in Nuclei -both occurring at the tree level).…”