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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We report new experimental limits on the \pi^0 -> \gamma X decay of theneutral pion into a photon and a light boson X followed by the decay X -> e+e-.If this process exist, one would expect a flux of high energy X's produced from\pi^0's generated by the proton beam in a neutrino target. The X's would thenpenetrate the downstream shielding and be observed in a neutrino detector viatheir decays. Using bounds from the NOMAD and PS191 neutrino experiments atCERN that searched for an excess of e+e- pairs from heavy neutrino decays,stringent limits on the branching ratio as small as Br(\pi^0 -> \gamma X) <10^{-15} are obtained. These limits are several orders of magnitude smallerthan the previous experimental and cosmological bounds. The obtained resultsare used to constrain models, where the X interacts with quarks and leptons, orit is a new vector boson mixing with photons, that transmits interactionbetween our world and hidden sectors consisting of SU(3)_C x SU(2)_L x U(1)_Ysinglet fields.

Stringent limits on the \pi^0 -> \gamma X, X -> e+e- decay from neutrino experiments and constraints on new light gauge bosons