Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited

Shima, Tatsushi

doi:https://doi.org/10.3390/sym17091524

Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited

Shima, Tatsushi

Symmetry, 2025, 17(9), 1524

アクセス数:24件（2026-02-16 00:54 集計）

固定URL: https://hdl.handle.net/11094/103503

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タイトル	Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited
著者	NRID 1000010222035 1000010222035 ORCID 0000-0001-9287-9953 0000-0001-9287-9953 researchmap permalink led0141215 led0141215 Scopus Author ID 7202589797 7202589797 著者名 Shima, Tatsushi
キーワード等	baryon number violation
	coherent scattering length
	neutron–antineutron oscillation
	physics beyond the standard model
	ultra-cold neutron
内容	Shima T., . Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited. Symmetry 17, 1524 (2025); https://doi.org/10.3390/sym17091524.
抄録	Neutron–antineutron oscillation (nnbar-osc) is a baryon number-violating process and a sensitive probe for physics beyond the standard model. Ultra-cold neutrons (UCNs) are attractive for nnbar-osc searches because of their long storage time, but earlier analyses indicated that phase shifts on wall reflection differ for neutrons and antineutrons, leading to severe decoherence and a loss of sensitivity. Herein, we revisit this problem by numerically solving the time-dependent Schrödinger equation for the two-component n/nbar wave function, explicitly including wall interactions. We show that decoherence can be strongly suppressed by selecting a wall material whose neutron and antineutron optical potentials are nearly equal. Using coherent scattering length data and estimates for antineutrons, we identify a Ni–Al alloy composition that matches the potentials within a few percent while providing a high absolute value, enabling long UCN storage. With such a bottle and an improved UCN source, the sensitivity could reach an oscillation period (Formula presented.) of the order 1010 s, covering most of the range predicted with certain grand unified models. This approach revives the feasibility of high-sensitivity nnbar-osc searches using stored UCNs and offers a clear path to probe baryon number violation far beyond existing limits.
出版者	Multidisciplinary Digital Publishing Institute (MDPI)
収録物名	Symmetry
巻(号)	17(9)
ページ	1524
刊行年月	2025-09-12
言語	英語
ハンドルURL	https://hdl.handle.net/11094/103503
eISSN	20738994
関連情報 (isIdenticalTo)	DOI (出版社版) https://doi.org/10.3390/sym17091524
アクセス権	open access
権利情報	This article is licensed under a Creative Commons Attribution 4.0 International License.
出版タイプ	Version of Record
カテゴリ	学術雑誌論文 Journal Article

資源タイプ	学術雑誌論文
ローカル資源タイプ	学術雑誌論文
DCMI資源タイプ	text
DCTERMS.bibliographicCitation	Symmetry. 2025, 17(9), p. 1524
DC.title	Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited
DC.creator	Shima, Tatsushi
DC.publisher	Multidisciplinary Digital Publishing Institute (MDPI)
DC.language' scheme='DCTERMS.RFC1766	英語
DC.type' scheme='DCTERMS.DCMIType	text
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2025-09-12
DC.identifier	https://doi.org/10.3390/sym17091524
DC.subject	baryon number violation
	coherent scattering length
	neutron–antineutron oscillation
	physics beyond the standard model
	ultra-cold neutron
DC.description	Shima T., . Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited. Symmetry 17, 1524 (2025); https://doi.org/10.3390/sym17091524.
DCTERMS.abstract	Neutron–antineutron oscillation (nnbar-osc) is a baryon number-violating process and a sensitive probe for physics beyond the standard model. Ultra-cold neutrons (UCNs) are attractive for nnbar-osc searches because of their long storage time, but earlier analyses indicated that phase shifts on wall reflection differ for neutrons and antineutrons, leading to severe decoherence and a loss of sensitivity. Herein, we revisit this problem by numerically solving the time-dependent Schrödinger equation for the two-component n/nbar wave function, explicitly including wall interactions. We show that decoherence can be strongly suppressed by selecting a wall material whose neutron and antineutron optical potentials are nearly equal. Using coherent scattering length data and estimates for antineutrons, we identify a Ni–Al alloy composition that matches the potentials within a few percent while providing a high absolute value, enabling long UCN storage. With such a bottle and an improved UCN source, the sensitivity could reach an oscillation period (Formula presented.) of the order 1010 s, covering most of the range predicted with certain grand unified models. This approach revives the feasibility of high-sensitivity nnbar-osc searches using stored UCNs and offers a clear path to probe baryon number violation far beyond existing limits.
DC.rights	This article is licensed under a Creative Commons Attribution 4.0 International License.
DC.format	103503
citation_title	Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited
citation_author	Shima, Tatsushi
citation_publisher	Multidisciplinary Digital Publishing Institute (MDPI)
citation_language	英語
citation_date	2025-09-12
citation_journal_title	Symmetry
citation_volume	17
citation_issue	9
citation_firstpage	1524
citation_doi	https://doi.org/10.3390/sym17091524
citation_public_url	https://hdl.handle.net/11094/103503

Experimental Search for Neutron–Antineutron Oscillation with the Use of Ultra-Cold Neutrons Revisited

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