Search for two-neutrino double electron capture on ¹²⁴Xe with the XMASS-I detector

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• 作者：XMASS Collaboration^⋆ ; K. Abe^a ; ^d ; K. Hiraide^a ; ^d ; K. Ichimura^a ; ^d ; Y. Kishimoto^a ; ^d ; K. Kobayashi^a ; ^d ; M. Kobayashi^a ; S. Moriyama^a ; ^d ; K. Nakagawa^a ; M. Nakahata^a ; ^d ; T. Norita^a ; H. Ogawa^a ; ^d ; H. Sekiya^a ; ^d ; O. Takachio^a ; A. Takeda^a ; ^d ; M. Yamashita^a ; ^d ; B.S. Yang^a ; ^d ; N.Y. Kim^b ; Y.D. Kim^b ; S. Tasaka^c ; ¹ ; J. Liu^d ; ² ; K. Martens^d ; Y. Suzuki^d ; R. Fujita^f ; K. Hosokawa^f ; K. Miuchi^f ; N. Oka^f ; Y. Onishi^f ; Y. Takeuchi^f ; ^d ; Y.H. Kim^g ; ^b ; J.S. Lee^g ; K.B. Lee^g ; M.K. Lee^g ; Y. Fukuda^h ; Y. Itowⁱ ; ^e ; R. Kegasaⁱ ; K. Kobayashiⁱ ; K. Masudaⁱ ; H. Takiyaⁱ ; H. Uchidaⁱ ; K. Nishijima^j ; K. Fujii^k ; I. Murayama^k ; S. Nakamura^k
• 关键词：Double electron capture ; Neutrino ; Liquid xenon
• 刊名：Physics Letters B
• 出版年：2016
• 出版时间：10 August 2016
• 年：2016
• 卷：759
• 期：Complete
• 页码：64-68
• 全文大小：329 K

文摘

Double electron capture is a rare nuclear decay process in which two orbital electrons are captured simultaneously in the same nucleus. Measurement of its two-neutrino mode would provide a new reference for the calculation of nuclear matrix elements whereas observation of its neutrinoless mode would demonstrate lepton number violation. A search for two-neutrino double electron capture on ¹²⁴Xe is performed using 165.9 days of data collected with the XMASS-I liquid xenon detector. No significant excess above background was observed and we set a lower limit on the half-life as class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269316301861&_mathId=si1.gif&_user=111111111&_pii=S0370269316301861&_rdoc=1&_issn=03702693&md5=fc6e63657d5313cf205ec921a9729ace" title="Click to view the MathML source">4.7×10²¹class="mathContainer hidden">class="mathCode">flow="scroll">4.7×1021 years at 90% confidence level. The obtained limit has ruled out parts of some theoretical expectations. We obtain a lower limit on the ¹²⁶Xe two-neutrino double electron capture half-life of class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269316301861&_mathId=si2.gif&_user=111111111&_pii=S0370269316301861&_rdoc=1&_issn=03702693&md5=a75d4b60192dc9a8ce7d05780a325819" title="Click to view the MathML source">4.3×10²¹class="mathContainer hidden">class="mathCode">flow="scroll">4.3×1021 years at 90% confidence level as well.