A comparative study of physics capabilities of a liquid argon and a water based liquid scintillator at DUNE

TL;DR

This study compares the physics capabilities of Liquid Argon TPC and Water-based Liquid Scintillator detectors at DUNE, showing the WbLS detector's advantages in CP phase resolution and robustness under new physics scenarios.

Contribution

It provides a comprehensive simulation-based comparison of LArTPC and WbLS detectors for DUNE, highlighting the superior performance of WbLS in key neutrino measurements.

Findings

WbLS outperforms LArTPC in resolving the CP phase.

WbLS better lifts the $ heta_{23}$ octant degeneracy.

WbLS maintains competitive precision with moderate energy resolutions.

Abstract

We present a comprehensive comparison of the physics sensitivities of a Liquid Argon Time Projection Chamber (LArTPC) and a Water-based Liquid Scintillator (WbLS) detector, considering their potential deployment as the fourth far detector module in the DUNE facility. Using GLoBES-based simulations, we evaluate their performance in measuring standard neutrino oscillation parameters ($\theta_{23}, \delta_{13}$ and $\Delta m^{2}_{31}$), both in standard 3-neutrino case, as well as in presence of new physics scenarios involving light sterile neutrinos and neutral-current non-standard interactions (NC NSI). Our findings show that THEIA (a WbLS-based detector) significantly outperforms LArTPC in resolving the CP phase $\delta_{13}$,- especially near maximal CP violation, and in lifting the octant degeneracy of $\theta_{23}$ due to its superior energy resolution and ability to clearly identify the second oscillation maximum. Furthermore, THEIA offers competitive reconstruction precision even with relatively moderate energy resolutions ($7-10\%/\sqrt{E}$) and demonstrates enhanced robustness under new physics scenarios. These results support the physics-driven case for a hybrid DUNE configuration utilizing both LArTPC and WbLS technologies for optimized sensitivity across the full spectrum of neutrino oscillation and physics beyond the standard model.