We explore the potential of the European Spallation Source (ESS) in probing physics within and beyond the Standard Model (SM), based on future measurements of coherent elastic neutrino-nucleus scattering (CE$\textit{ν}$NS). We consider two SM physics cases, namely the weak mixing angle and the nuclear radius. Regarding physics beyond the SM, we focus on neutrino generalized interactions (NGIs) and on various aspects of sterile neutrino and sterile neutral lepton phenomenology. For this, we explore the violation of lepton unitarity, active-sterile oscillations as well as interesting upscattering channels such as the sterile dipole portal and the production of sterile neutral leptons via NGIs. The projected ESS sensitivities are estimated by performing a statistical analysis considering the various CE$\textit{ν}$NS detectors and expected backgrounds. We find that the enhanced statistics achievable in view of the highly intense ESS neutrino beam, will offer a drastic improvement in the current constraints obtained from existing CE$\textit{ν}$NS measurements. Finally, we discuss how the ESS has the potential to provide the leading CE$\textit{ν}$NS-based constraints, complementing also further experimental probes and astrophysical observations.

India

Ayan Chattaraj

Anirban Majumdar

Spain

Dimitrios Papoulias

Rahul Srivastava

Probing conventional and new physics at the ESS with coherent elastic neutrino-nucleus scattering

We explore the potential of reactor antineutrino-induced Coherent Elastic Neutrino-Nucleus Scattering (CE <italic>&#957;</italic>NS) data from the CONUS+ experiment to investigate both the Standard Model (SM) and Beyond Standard Model (BSM) scenarios. Alongside CE <italic>&#957;</italic>NS, Elastic Neutrino-Electron Scattering (E <italic>&#957;</italic>ES) events are also included in our analysis, enabling more stringent constraints on new physics. Within the SM, we examine the weak mixing angle as a precision test of the electroweak sector. For BSM scenarios, we constrain the parameter space of light mediators arising from neutrino generalized interactions (NGI), while also setting limits on the electromagnetic properties of neutrinos, including their charge radius, millicharge, and magnetic moment.