English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We consider scenarios with a heavy $Z^\prime$ gauge boson with flavournon-universal quark and lepton couplings with the goal to illustrate how thecancellation of gauge anomalies generated by the additional U(1)$^\prime$ gaugesymmetry would imply correlations between FCNC processes in the quark sector,in the lepton sector and most interestingly between quark flavour and leptonflavour violating processes. We present scenarios with only left-handedflavour-violating $Z^\prime$ couplings and those with also right-handedflavour-violating couplings. These are characterized by a small number of freeparameters but in contrast to gauge anomaly cancellation in the Standard Model,that takes place separately within each generation, in our scenarios anomalycancellation involves simultaneously quarks and leptons of all threegenerations. Our models involve, beyond the ordinary quarks and leptons, threeheavy right-handed neutrinos. The models with only left-handed FCNCs of$Z^\prime$ involve beyond $g_{Z^\prime}$ and $M_{Z^\prime}$ two real parameterscharacterizing the charges of all fermions under the U(1)$^\prime$ gaugesymmetry and the CKM and PMNS ones in the quark and lepton sectors,respectively. The models with the right-handed FCNCs of $Z^\prime$ involve fewadditional parameters. Imposing constraints from well measured $\Delta F=2$observables we identify interesting correlations that involve e.g.$\varepsilon'/\varepsilon$, $B_{s,d}\to\mu^+\mu^-$, $B\to K(K^*) \ell^+\ell^-$,$K^+\rightarrow\pi^+\nu\bar\nu$, $K_{L}\rightarrow\pi^0\nu\bar\nu$ and purelylepton flavour violating decays like $\mu\to e\gamma$, $\mu\to 3 e$, $\tau\to3\mu$ and $\mu-e$ conversion} among others. Also $(g-2)_{\mu,e}$ areconsidered. The impact of the experimental $\mu\to e\gamma$, $\mu\to 3 e$ andin particular $\mu-e$ conversion bounds on rare $K$ and $B$ decays isemphasized.

Quark-Lepton Connections in $Z^\prime$ Mediated FCNC Processes: Gauge Anomaly Cancellations at Work