The \theta_{13} and \delta_{CP} sensitivities of the SPL-Frejus project revisited

TL;DR

This paper reevaluates the sensitivity of the SPL-Frejus project to the neutrino mixing angle heta_{13} and the CP-violating phase \,delta_{CP}, suggesting potential improvements with optimized beam parameters and detector setup.

Contribution

It provides an optimized configuration for the CERN SPL beam line to enhance sensitivities to heta_{13} and \,delta_{CP}, highlighting possible upgrades for better experimental outcomes.

Findings

20% gain in heta_{13} sensitivity with higher beam energy and longer decay tunnel

Optimized beam parameters can significantly improve CP violation sensitivity

Detector setup at Frejus is effective for neutrino oscillation measurements

Abstract

An optimization of the CERN SPL beam line has been performed guided by the sensitivities to the \theta_{13} mixing angle and to the \delta_{CP} Dirac CP violating phase. A UNO-like 440 ktons water Cerenkov detector located at 130 km from the target in a new foreseen Frejus laboratory has been used as a generic detector. Concerning the \delta_{CP} independent \theta_{13} sensitivity, a gain of about 20% may be reached using a 3.5 GeV proton beam with a 40 m long, 2 m radius decay tunnel compared to the up to now considered 2.2 GeV beam energy and 20 m long, 1 m radius decay tunnel. This may motivate new machine developments to upgrade the nominal SPL proton beam energy.