Speaker
Description
The JSNS2 (J-PARC Sterile Neutrino Search at J-PARC Spallation Neutron Source) experiment and its upcoming Phase-II upgrade present a compelling frontier in neutrino physics, uniquely positioned to test the eV-scale sterile neutrino anomaly. Rather than relying solely on theoretical phenomenology, this presentation focuses on the experimental mechanics and the unique beam characteristics that make JSNS2 highly competitive. We will systematically explore the J-PARC Materials and Life Science Experimental Facility (MLF) as an exceptionally intense source of Decay-At-Rest (DAR) neutrinos.A primary focus will be placed on exploiting the $\mu^+$ Decay-At-Rest (muDAR) spectrum for the $\bar{\nu}_\mu \to \bar{\nu}_e$ appearance search, leveraging the well-understood energy distribution to meticulously control systematic uncertainties. Furthermore, we will highlight the critical role of Kaon Decay-At-Rest (KDAR). Producing monochromatic 236 MeV $\nu_\mu$, KDAR serves as a rare and invaluable "standard candle" in neutrino physics. We will discuss its application in precision neutrino-nucleus cross-section measurements, energy calibration, and probing exotic dark sector physics.From a metrological standpoint, the talk will also address the detector instrumentation, specifically the deployment of Gadolinium-loaded Liquid Scintillator (Gd-LS) targets. We will examine the operational strategies for maximizing the signal-to-noise ratio in a high-background accelerator environment using prompt-delayed coincidence logic. Finally, the presentation will outline the strategic enhancements of JSNS2-II, emphasizing how the addition of a far detector will break parameter degeneracies and definitively establish the existence or exclusion of the sterile neutrino within the targeted parameter space.
