Measurement of the neutron lifetime using a magneto-gravitational trap

Abstract

Precision measurements of the free neutron lifetime ${\tau }_n$, 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 ${\tau }_n$ to a precision of 0.1~s. However, the two dominant techniques to measure ${\tau }_n$ (colloquially beam and bottle measurements) disagree by nearly 10~s. UCN$\tau$ 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 - ${\tau }_n=877.7\pm 0.7_{\text{(stat.)}}+0.4/-0.2_{\text{(sys.)}}$~s. I will also present Monte Carlo simulations of systematic effects in the experiment including heating and spectral cleaning.

arXiv commentTalk presented CIPANP2018. 6 pages, 1 figure, LaTeX

References in corpus (5)

• The neutron and its role in cosmology and particle physics
• Beta Decays and Non-Standard Interactions in the LHC Era
• Measurement of the neutron lifetime using an asymmetric magneto- gravitational trap and in situ detection
• New result for the neutron $\beta$-asymmetry parameter $A_0$ from UCNA
• Spin flip loss in magnetic confinement of ultracold neutrons for neutron lifetime experiments

Cited by in corpus (1)

• Exotic decay channels are not the cause of the neutron lifetime anomaly