On possibility of determining neutrino mass hierarchy by the charged-current and neutral-current events of supernova neutrinos in scintillation detectors

Fei-Fan Lee; Feng-Shiuh Lee; Kwang-Chang Lai

doi:10.1140/epjc/s10052-019-6633-7

EPJ

On possibility of determining neutrino mass hierarchy by the charged-current and neutral-current events of supernova neutrinos in scintillation detectors

Fei-Fan Lee¹, Feng-Shiuh Lee² and Kwang-Chang Lai³^*

¹ Department of Physics, Jimei University, Xiamen, 361021, Fujian, People’s Republic of China
² Department of Electrophysics, National Chiao Tung University, Hsin-chu, 300, Taiwan
³ Center for General Education, Chang Gung University, Kwei-Shan, Taoyuan, 333, Taiwan

Received: 13 September 2018
Accepted: 28 January 2019
Published online: 12 February 2019

Abstract

One of the unresolved mysteries in neutrino physics is the neutrino mass hierarchy. We present a new method to determine neutrino mass hierarchy by comparing the events of inverse beta decays (IBD), ${\bar{\nu }}_e + p\rightarrow n + e^+$ , and neutral current (NC) interactions, $\nu ({\overline{\nu }}) + p\rightarrow \nu ({\overline{\nu }}) + p$ , of supernova neutrinos from accretion and cooling phases in scintillation detectors. Supernova neutrino flavor conversions depend on the neutrino mass hierarchy. On account of Mikheyev–Smirnov–Wolfenstein effects, the full swap of the ${\bar{\nu }}_e$ flux with the ${\bar{\nu }}_x$ ( $x=\mu ,~\tau$ ) one occurs in the inverted hierarchy, while such a swap does not occur in the normal hierarchy. In consequence, the ratio of high energy IBD events to NC events for the inverted hierarchy is higher than in the normal hierarchy. Since the luminosity of ${\bar{\nu }}_e$ is larger than that of $\nu _x$ in accretion phase while the luminosity of ${\bar{\nu }}_e$ becomes smaller than that of $\nu _x$ in cooling phase, we calculate this ratio for both accretion and cooling phases. By analyzing the change of this event ratio from accretion phase to cooling phase, one can determine the neutrino mass hierarchy.

12 Internat. Congress of the Balkan Physical Union
July 8-12, 2025
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EPJ

On possibility of determining neutrino mass hierarchy by the charged-current and neutral-current events of supernova neutrinos in scintillation detectors

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