The Search for Mirror Neutrons in 2020 Experiment at SNS

As a candidate for dark matter, the world of mirror matter is one with which we cannot interact directly; at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratories, our group has attempted to understand mirror matter by observing neutron-to-mirror neutron oscillations. The transformations from neutrons to mirror neutrons and back can act as a portal between matter and mirror matter. I was tasked with analyzing the data from the experiment performed at the SNS in November of 2020. This experiment consisted of a beam of cold neutrons that would be exposed to a magnetic field where in the center was a cadmium absorber. Neutrons in this magnetic field were supposed to be converted to mirror neutrons that can pass the absorber without interaction; then, while they are still in the magnetic field, they regenerate back into ordinary neutrons that are ultimately detected. My main goal is to characterize the intensity of the initial neutron beam, which is used to calculate the probability of the transformations occurring. I analyzed the data primarily using python along with C++ for further optimization. Six intensity calibration data files were analyzed, and among these six, various numbers of polycarbonate plates were used to attenuate the initial neutron beam. After defining a region of interest where regenerated neutrons have hit the detector along with a region of background resulting from scattered neutrons, I employed statistical methods to remove the background from under the beam intensity peak. Plotting the intensity of the peak of the data from these six files against the respective number of plates used in each run could be utilized to determining the intensity of the initial beam through fitting. With a determined intensity, the probability of quantum mechanical processes behind the oscillations into mirror particles can be further understood.