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| Natura: | Preprint |
| Pubblicazione: |
2024
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| Accesso online: | https://arxiv.org/abs/2412.08638 |
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| _version_ | 1866913640154660864 |
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| author | Van Goffrier, Graham |
| author_facet | Van Goffrier, Graham |
| contents | Neutrinoless double-beta ($0νββ$) decay is an as-yet unobserved nuclear process, which stands to provide crucial insights for model-building beyond the Standard Model of particle physics. Its detection would simultaneously confirm the hypothesis that neutrinos are Majorana fermions, thus violating lepton-number conservation, and provide the first measurement of the absolute neutrino mass scale. This work aims to improve the estimation within chiral effective field theory of the so-called ''contact term'' for $0νββ$-decay, a short-range two-nucleon effect which is unaccounted for in traditional nuclear approaches to the process. We conduct a thorough review of the justifications for this contact term and the most precise computation of its size to date ($g_ν^{NN}$ = 1.3(6) at renormalisation point $μ=m_π$), whose precision is limited by a truncation to elastic intermediate hadronic states. We then perform an extension of this analysis to a subleading class of inelastic intermediate states which we characterise, delivering an updated figure for the contact coefficient ($g_ν^{NN}$ = 1.4(3) at $μ=m_π$) with uncertainty reduced by half. Such ab initio nuclear results, especially with enhanced precision, show promise for the resolution of disagreements between estimates of $0νββ$ from different many-body methods. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2412_08638 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | An Improved Precision Calculation of the $0νββ$ Contact Term within Chiral Effective Field Theory Van Goffrier, Graham High Energy Physics - Phenomenology Nuclear Theory Neutrinoless double-beta ($0νββ$) decay is an as-yet unobserved nuclear process, which stands to provide crucial insights for model-building beyond the Standard Model of particle physics. Its detection would simultaneously confirm the hypothesis that neutrinos are Majorana fermions, thus violating lepton-number conservation, and provide the first measurement of the absolute neutrino mass scale. This work aims to improve the estimation within chiral effective field theory of the so-called ''contact term'' for $0νββ$-decay, a short-range two-nucleon effect which is unaccounted for in traditional nuclear approaches to the process. We conduct a thorough review of the justifications for this contact term and the most precise computation of its size to date ($g_ν^{NN}$ = 1.3(6) at renormalisation point $μ=m_π$), whose precision is limited by a truncation to elastic intermediate hadronic states. We then perform an extension of this analysis to a subleading class of inelastic intermediate states which we characterise, delivering an updated figure for the contact coefficient ($g_ν^{NN}$ = 1.4(3) at $μ=m_π$) with uncertainty reduced by half. Such ab initio nuclear results, especially with enhanced precision, show promise for the resolution of disagreements between estimates of $0νββ$ from different many-body methods. |
| title | An Improved Precision Calculation of the $0νββ$ Contact Term within Chiral Effective Field Theory |
| topic | High Energy Physics - Phenomenology Nuclear Theory |
| url | https://arxiv.org/abs/2412.08638 |