[tw-hepnet] NCTS Seminar - Particle Physics Journal Club 2026/03/23 (Mon.) 12:30

[Yu-Rou Tsang]

***NCTS Seminar***

Particle Physics Journal Club

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Speaker: Dr. Manoj Singh (Academia Sinica)

Talk title: Discovery Potential of Neutrinoless Double-Beta Decay

Time: 2026/03/23 (Mon.) 12:30

Place: NCTS Physics 4F Lecture Hall, Cosmology Hall, NTU

 

Abstract:
Neutrinoless double-beta decay (0\nu\beta\beta) is a lepton-number-violating nuclear transition that can occur only if neutrinos are Majorana particles. Its observation would establish the violation of total lepton number, demonstrate the Majorana nature of neutrinos, and provide a sensitive probe of the absolute neutrino mass scale through the effective Majorana mass, with profound implications for physics beyond the Standard Model [1,2]. Next-generation 0\nu\beta\beta experiments, employing a diverse set of candidate isotopes, are designed to comprehensively probe the parameter space corresponding to the inverted neutrino mass ordering and to extend sensitivity into the normal ordering regime. Recent cosmological hints favoring the normal mass ordering further motivate these searches, although probing this region remains challenging under the current theoretical uncertainties associated with nuclear matrix elements. Recognizing the critical role of theoretical inputs, uncertainties in nuclear matrix elements, the axial-vector coupling, and phase-space factors, drawn from recent ab initio and phenomenological nuclear-structure calculations, are systematically incorporated to evaluate the projected sensitivity of future 0\nu\beta\beta experiments [3]. A detailed quantitative assessment of these theoretical limitations, encompassing both nuclear and particle physics inputs, demonstrates how such uncertainties shape the experimental outlook, guiding the interpretation of results and informing strategies to optimize the discovery potential of forthcoming searches. Our results and the current presentation emphasize that reducing theoretical uncertainties will require both refined nuclear modeling and dedicated measurements, which are essential for sharpening the predictions and sensitivity of future 0\nu\beta\beta searches and for identifying directions where further research is needed in both theory and experiment.

[1] M. K. Singh et al., Exposure-background duality in the searches of neutrinoless double beta decay, Phys. Rev. D 101, 013006 (2020). 

[2] M. K. Singh et al. (TEXONO Collaboration), Projections of discovery potentials from expected background, Phys. Rev. D 109, 032001 (2024). 

[3] M. K. Singh et al., Impact of theoretical constraints in the sensitivity estimation for neutrinoless double beta decay, Int. J. Mod. Phys. A 40, 18, 2550050 (2025).