The Analysis of Systematic Effects of Detection Efficiencies in the BL2 In-Beam Neutron Lifetime Measurement

Precision measurements of neutron beta decay can provide answers to some of the most fundamental questions in particle physics, astrophysics and cosmology. Neutron beta decay, a semi-leptonic decay, is the simplest form of nuclear beta decay; therefore, it provides a clean test of the weak interaction of the Standard Model (SM). A precise measurement of the neutron lifetime and λ the ratio of axial vector and vector coupling constants of the weak interaction, allows for a determination of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element V_ud that is free from nuclear structure effects. The SM predicts that the CKM matrix is unitary; therefore, the measurement of the neutron lifetime provides an important test of the SM. The neutron lifetime is also an important input parameter into early universe Big Bang nucleosynthesis calculations. The in-beam method of measuring the neutron lifetime requires the absolute counting of decay protons in a neutron beam of precisely known flux. Improvements in the neutron and proton detection systems as well as the use of a new analysis technique and apparatus upgrades allow for a rigorous re-examination of the systematic effects associated with this method. This work will discuss the results of new systematic studies regarding the detection efficiencies of protons and molecular hydrogen.