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

A recently proposed scale invariant extension of the standard model ismodified such that it includes a Dark Matter candidate which can annihilateinto gamma-rays. For that a non-zero $U(1)_Y$ hypercharge $Q$ is assigned tothe fermions in a QCD-like hidden sector. The Nambu-Goldstone bosons, thatarise due to dynamical chiral symmetry breaking in the hidden sector, are coldDark Matter candidates, and the extension allows them to annihilate into twophotons, producing a gamma-ray line spectrum. We find that the gamma-ray lineenergy must be between 0.7 TeV and 0.9 TeV with the velocity-averagedannihilation cross section $10^{-30}\sim 10^{-26}$ cm^3/s for $Q=1/3$. With anon-zero hypercharge $Q$, the hidden sector is no longer completely dark andcan be directly probed by collider experiments.

Gamma-ray Line from Nambu-Goldstone Dark Matter in a Scale Invariant Extension of the Standard Model