2023/08/30 by M. Beck, Beck, M., W. Heil +11
Chemistry · Physics and Astronomy · #Advanced NMR Techniques and Applications #Atomic and Subatomic Physics Research #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Physics and Applications
paper · pdf · doi:10.48550/arxiv.2308.16170
openalex publication_date 2023/08/30 · openalex created_date 2023/09/02 · openalex updated_date 2026/07/28
On the basis of revisions of some of the systematic errors, we reanalyzed the electron-antineutrino angular correlation (a coefficient) in free neutron decay inferred from the recoil energy spectrum of the protons which are detected in 4π by the aSPECT spectrometer. With a = -0.10402(82) the new value differs only marginally from the one published in 2020. The experiment also has sensitivity to b, the Fierz interference term. From a correlated (b,a) fit to the proton recoil spectrum, we derive a limit of b = -0.0098(193) which translates into a somewhat improved 90 % CL region of -0.041 ≤ b ≤ 0.022 on this hypothetical term. Tighter constraints on b can be set from a combined(c) analysis of the PERKEO~III (β asymmetry) and aSPECT measurement which suggests a finite value of b with b(c) = -0.0181 ± 0.0065 deviating by 2.82σ from the standard model.