The paper titled "Search for nonresonant pair production of Higgs bosons in the \(b\bar{b}b\bar{b}\) final state in \(pp\) collisions at \(\sqrt{s} = 13\ \mathrm{TeV}\) with the ATLAS detector", to which Shota Hayashida has contributed as the main analyst, was published in Physical Review D.

This paper presents a search for nonresonant Higgs boson pair production in the \(b\bar{b}b\bar{b}\) final state in the ATLAS experiment. No evidence for nonresonant Higgs boson pair production is found, but the result provides the upper limit on the cross section for nonresonant Higgs boson pair production and constraints on modifiers to the \(HHH\) and \(HHVV\) couplings. Dr. Hayashida was responsible for developing a search sensitivity improvement method using categorization, validating the background event estimation method, and deriving the results. More information about the paper is reported below.

Paper information:
G. Aad et al. (The ATLAS Collaboration), "Search for nonresonant pair production of Higgs bosons in the \(b\bar{b}b\bar{b}\) final state in \(pp\) collisions at \(\sqrt{s} = 13\ \mathrm{TeV}\) with the ATLAS detector"
[Phys. Rev. D, 108, 052003 (2023). DOI:10.1103/PhysRevD.108.052003]