2024/05/20 by Joel Kostensalo, Kostensalo, Joel, E. Lisi +5 · 1 citation
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Nuclear physics research studies #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2405.11920
openalex publication_date 2024/05/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We analyze the 115In β-decay energy spectrum through the spectral moment method (SMM), previously introduced in the context of 113Cd β decay. The spectral moments μn are defined as averaged n\rm th powers of the β particle energy, characterizing the spectrum normalization (n=0) and shape (n≥ 1) above a given threshold. For 115In, we consider three independent datasets characterized by different thresholds. We also consider three nuclear model calculations with two free parameters: the ratio of axial-vector to vector couplings, r=g\rm A/g\rm V, and the small vector-like relativistic nuclear matrix element (NME), s=s-NME. By using the most recent of the three datasets, we show that the first few spectral moments can determine (r, s) values in good agreement with those obtained by full-fledged experimental fits. We then work out the SMM results for the other datasets. We find that, although g\rm A quenching is generally favored, the preferred quenching factors may differ considerably depending on the chosen experimental data and nuclear models. We discuss various issues affecting both the overall normalization and the low-energy behaviour of the measured and computed spectra, and their joint effects on the experimentally quoted half-life values. Further 115In β-decay data at the lowest possible energy threshold appear to be crucial to clarify these issues.