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/

Zendy Plus

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

Zendy Tools

Zendy Open

Galaxy clusters, employed by Zwicky to demonstrate the existence of darkmatter, pose new stringent tests. If merging clusters demonstrate that darkmatter is self-interacting with cross section $\sigma/m\sim 2$ cm$^2$/gr,MACHOs, primordial black holes and light axions that build MACHOs are ruled outas cluster dark matter. Recent strong lensing and X-ray gas data of the quiterelaxed and quite spherical cluster A1835 allow to test the cases of darkmatter with Maxwell-Boltzmann, Bose-Einstein and Fermi-Dirac distribution, nextto Navarro-Frenck-White profiles. Fits to all these profiles are formallyrejected at over $5\sigma$, except in the fermionic situation. Theinterpretation in terms of (nearly) Dirac neutrinos with mass of$1.61^{+0.19}_{-0.30}$ eV/$c^2$ is consistent with results on the clusterA1689, with the WMAP, Planck and DES dark matter fractions and with thenondetection of neutrinoless double $\beta$-decay. The case will be tested inthe 2018 KATRIN experiment.

Subjecting dark matter candidates to the cluster test