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

Abstract

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

arXiv comment6 pages, 2 figures, accepted for publication in Phys. Rev. C

References in corpus (6)

• The detection of neutron clusters
• Can Modern Nuclear Hamiltonians Tolerate a Bound Tetraneutron?
• On the possibility of generating a 4-neutron resonance with a {\boldmath $T=3/2$} isospin 3-neutron force
• Can realistic nuclear interactions tolerate a resonant tetraneutron ?
• The quest for light multineutron systems
• Low energy structures in nuclear reactions with 4n in the final state

Cited by in corpus (1)

• Calculation of tetraneutron-induced reaction cross sections with optical and Hauser-Feshbach statistical models