2025/09/15 by M. Anholm, Anholm, Melissa, J.A. Behr +13
Physics and Astronomy · #Atomic and Subatomic Physics Research #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Nuclear Experiment (nucl-ex) #Nuclear Theory (nucl-th) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2509.11502
openalex publication_date 2025/09/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
By extending our analysis and simulations of our 37K β-decay data set to allow the β asymmetry with respect to nuclear spin to vary with β energy Eβ, we have gained sensitivity to new physics that depends on a helicity factor for the β, mβ/Eβ. In particular, we constrain Lorentz scalar and tensor quark-lepton interaction strengths at a sensitivity complementary to the similar Fierz interference term in neutron β decay. Our result for that new physics is a Fierz interference term b = 0.033 ± 0.084 (stat) ± 0.039 (syst), consistent with the standard model electroweak interaction value b=0. We consider presently achieved complementarity to β-decay and particle physics experiments, along with projectable technical improvements to our method.