2018/10/01 by Nathan Callahan, Callahan, Nathan · 4 citations
Physics and Astronomy · #Atomic and Subatomic Physics Research #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #Instrumentation and Detectors (physics.ins-det) #Nuclear Experiment (nucl-ex) #Quantum, superfluid, helium dynamics
paper · pdf · doi:10.48550/arxiv.1810.00958
openalex publication_date 2018/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Precision measurements of the free neutron lifetime τn, when combined with measurements of the axial vector form factor, can be used to test unitarity of the CKM matrix. Non-unitarity is a signal for physics Beyond the Standard Model (BSM). Sensitivity to BSM physics requires measurements of τn to a precision of 0.1~s. However, the two dominant techniques to measure τn (colloquially beam and bottle measurements) disagree by nearly 10~s. UCNτ is a neutron lifetime experiment using a magneto-gravitational trap and an in-situ neutron detector. Neutrons in this trap are not susceptible to loss on material walls as in previous bottle measurements. Additionally, the in-situ detector allows spectral monitoring of the trapped Ultracold Neutrons. In this talk, I will present our most recent result - τn=877.7±0.7_(stat.)+0.4/-0.2_(sys.)~s. I will also present Monte Carlo simulations of systematic effects in the experiment including heating and spectral cleaning.