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 survey the phenomenological constraints on abelian gauge bosons havingmasses in the MeV to multi-GeV mass range (using precision electroweakmeasurements, neutrino-electron and neutrino-nucleon scattering, electron andmuon anomalous magnetic moments, upsilon decay, beam dump experiments, atomicparity violation, low-energy neutron scattering and primordialnucleosynthesis). We compute their implications for the three parameters thatin general describe the low-energy properties of such bosons: their mass andtheir two possible types of dimensionless couplings (direct couplings toordinary fermions and kinetic mixing with Standard Model hypercharge). We arguethat gauge bosons with very small couplings to ordinary fermions in this massrange are natural in string compactifications and are likely to be generic intheories for which the gravity scale is systematically smaller than the Planckmass - such as in extra-dimensional models - because of the necessity tosuppress proton decay. Furthermore, because its couplings are weak, in thelow-energy theory relevant to experiments at and below TeV scales the chargegauged by the new boson can appear to be broken, both by classical effects andby anomalies. In particular, if the new gauge charge appears to be anomalous,anomaly cancellation does not also require the introduction of new lightfermions in the low-energy theory. Furthermore, the charge can appear to beconserved in the low-energy theory, despite the corresponding gauge bosonhaving a mass. Our results reduce to those of other authors in the specialcases where there is no kinetic mixing or there is no direct coupling toordinary fermions, such as for recently proposed dark-matter scenarios.

New Constraints (and Motivations) for Abelian Gauge Bosons in the MeV-TeV Mass Range