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

Background: The existence of a tetraneutron comprising four neutrons has longbeen debated.  Purpose: Motivated by a recent observation of particle-stable tetraneutrons,we investigated potential particle-stable tetraneutron emission in thermalneutron-induced $^{235}$U fission using a nuclear research reactor.  Methods: We performed $\gamma$-ray spectroscopy for a $^{88}$SrCO$_3$ sampleirradiated in a reactor core. Stable $^{88}$Sr was expected to produce$^{91}$Sr by a tetraneutron-induced ($^4n$,n) reaction; hence, observation of$\gamma$-rays followed by $\beta$ decay of $^{91}$Sr would indicateparticle-stable tetraneutron emission.  Results: The $\gamma$-ray spectrum of an irradiated $^{88}$SrCO$_3$ sampledid not show any photopeak for $^{91}$Sr.  Conclusion: The emission rate of particle-stable tetraneutrons, if theyexist, is estimated to be lower than $8\times 10^{-7}$ per fission at the 95%confidence level, assuming the cross-sections of reactions induced byhypothetical particle-stable tetraneutrons.

Search for particle-stable tetraneutrons in thermal fission of $^{235}$U