Directional Observation of Cold Dark Matter Particles (WIMP) in Light Target Experiments

For the last 10 years, the search for dark matter (DM) was carried out taking into account the fact that the DM particles are WIMPs (Weakly Interacted Massive Particles) which were introduced in supersymmetric extensions of the Standard Model. Many experiments such as XENON1T, DarkSide, CRESST, etc. set the constraints on the WIMP-nucleon elastic interaction cross sections for different assumed WIMP masses. Methods for detecting WIMPs could play a special role, allowing one to determine the directions of the tracks of recoil nuclei and, therefore, to determine the preferred direction of the WIMP flux. In this work, we analyze the capabilities of such direct detection experiments through analyzing the lengths and directions of the tracks of recoil nuclei. Taking into account the existing experimental constraints, we conclude that the optimal target would be a lower density target containing nuclei of the CNO group, for example, liquid propane.

Adjusting neutrino interaction models and evaluating uncertainties using NOvA near detector data

The two-detector design of the NOvA neutrino oscillation experiment, in which two functionally identical detectors are exposed to an intense neutrino beam, aids in canceling leading order effects of cross-section uncertainties. However, limited knowledge of neutrino interaction cross sections still gives rise to some of the largest systematic uncertainties in current oscillation measurements. We show contemporary models of neutrino interactions to be discrepant with data from NOvA, consistent with discrepancies seen in other experiments. Adjustments to neutrino interaction models in GENIE are presented, creating an effective model that improves agreement with our data. We also describe systematic uncertainties on these models, including uncertainties on multi-nucleon interactions from a newly developed procedure using NOvA near detector data.