Radiative Corrections to Inverse Beta Decay at Low Energies Improve Cross-Section Predictions by Incorporating Permille-Level Contributions
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The accurate detection of neutrinos relies on precisely predicting the rate of inverse beta decay, a crucial process in many neutrino experiments. Oleksandr Tomalak from the Institute of Theoretical Physics, Chinese Academy of Sciences, and colleagues now present the most accurate predictions for this process to date, accounting for subtle effects arising from electromagnetic radiation.
This research significantly improves upon previous calculations by consistently incorporating contributions from fundamental forces, including electromagnetism, chromodynamics, and the electroweak interaction, and delivers a comprehensive analysis of all contributing factors.
The team’s detailed calculation, which incorporates contributions at the permille level, will enable more precise measurements of neutrino oscillation parameters and facilitate the search for new physics using reactor antineutrinos at nuclear power plants. Reactor Neutrinos and Short-Baseline Anomalies This research area focuses on understanding discrepancies between predicted and measured rates of antineutrinos originating from nuclear reactors, a phenomenon known as the reactor anomaly. This anomaly is significant because it potentially indicates the existence of sterile neutrinos or new physics beyond the current Standard Model of particle physics. Numerous experiments, including Daya Bay, RENO, Double Chooz, PROSPECT, STEREO, NEOS, and SoLid, are dedicated to studying neutrino oscillations over short distances, crucial for investigating this anomaly and searching for these elusive particles. A substantial body of theoretical work supports these experiments, focusing on precise calculations of neutrino fluxes, oscillation probabilities, and the complex radiative corrections needed for accurate predictions.,. Antineutrino-Proton Interaction via Effective Field Theory Scientists have developed a precise method for calculating how antineutrinos interact with protons, a fundamental process in reactor neutrino experiments. The study centers on inverse beta decay, where an antineutrino transforms a proton into a positron and a neutron, and aims to provide the most accurate predictions of this process to date. Researchers began with an effective field theory, known as heavy baryon chiral perturbation theory, to systematically incorporate contributions from various energy scales, including electromagnetic, chromodynamic, and electroweak interactions. This approach separates effects, treating high-energy contributions as low-energy coupling constants within the effective theory.
The team formulated the interaction using a well-established framework, incorporating fundamental constants and values derived from neutron decay measurements. A key innovation involved a full analytical integration over phase space when evaluating bremsstrahlung contributions, avoiding approximations used in previous calculations and capturing subtle effects in the final-state kinematics. This technique enabled the calculation of the positron energy spectrum, a significant improvement over earlier studies. Furthermore, the research extended beyond simple cross-section calculations, providing two- and three-dimensional distributions to account for the influence of radiated photons on detector signatures.,. Precise Prediction of Reactor Antineutrino Spectra Scientists have achieved the most accurate predictions to date for the inverse beta decay process, a crucial reaction in reactor antineutrino experiments, by employing heavy baryon chiral perturbation theory. This work delivers a complete budget of electromagnetic radiative corrections, consistently incorporating contributions from quantum electrodynamics, chromodynamics, and electroweak interactions for the first time.
The team successfully calculated the positron energy spectrum, accounting for radiative corrections to an unprecedented degree of accuracy, and improved upon previous evaluations by including contributions at the permille level. The research provides a detailed analysis of the charged-current antineutrino-proton elastic scattering process, specifically the reaction where an antineutrino interacts with a proton to produce a positron and a neutron. By treating nucleons as heavy fields within an effective field theory, scientists were able to systematically incorporate effects from higher energy scales, ensuring a comprehensive understanding of the interaction. The calculation utilizes well-established fundamental constants and incorporates values derived from previous experiments. Notably, the team analytically integrated over phase space without the zero-recoil approximation, capturing leading enhancements near kinematic endpoints, and providing the positron energy spectrum. Furthermore, the study delivers two- and three-dimensional distributions to accurately account for the influence of radiated photons on detector signatures.,.
Precision Neutrino Cross Sections from Radiative Corrections This work presents a refined calculation of radiative corrections within the inverse beta decay process, crucial for understanding neutrino interactions at reactor antineutrino energies. Scientists achieved, for the first time, a consistent inclusion of quantum electrodynamic, electroweak, and quantum chromodynamic effects, utilising heavy-baryon chiral perturbation theory. The results encompass a detailed positron energy spectrum and a fully analytical phase-space integration, moving beyond previous approximations. The calculations reveal previously unaccounted for effects in the inverse beta decay cross sections, at the percent and permille levels, enhancing the precision of current and future neutrino experiments. These improvements are particularly relevant for normalising reactor antineutrino flux, enabling more accurate measurements of neutrino oscillation parameters, and searching for new physics. While the calculations represent a significant advancement, the authors acknowledge limitations inherent in theoretical modelling and emphasise the importance of ongoing experimental validation. Future research may focus on applying these refined cross sections to supernova neutrino detection, providing a more robust foundation for understanding these energetic events. 👉 More information 🗞 On radiative corrections to inverse beta decay at low energies 🧠 ArXiv: https://arxiv.org/abs/2512.07957 Tags: