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.
@article{arxiv.1810.00958,
title = {Measurement of the neutron lifetime using a magneto-gravitational trap},
author = {Nathan Callahan},
journal= {arXiv preprint arXiv:1810.00958},
year = {2018}
}