Multisite event discrimination for the majorana demonstrator

The Majorana Demonstrator is searching for neutrinoless double-beta decay (0 ν β β ) in ⁷⁶Ge using arrays of point-contact germanium detectors operating at the Sanford Underground Research Facility. Background results in the 0 ν β β region of interest from data taken during construction, commissioning, and the start of full operations have been recently published. A pulse shape analysis cut applied to achieve this result, named A v s E , is described in this paper. This cut is developed to remove events whose waveforms are typical of multisite energy deposits while retaining (90 ±3.5 )% of single-site events. This pulse shape discrimination is based on the relationship between the maximum current and energy, and tuned using ²²⁸Th calibration source data. The efficiency uncertainty accounts for variation across detectors, energy, and time, as well as for the position distribution difference between calibration and 0 ν β β events, established using simulations.