Eur. Phys. J. C (2006) 45: 643-657
https://doi.org/10.1140/epjc/s2005-02455-x

Experimental Physics

The Θ₁₃ and δ _CP sensitivities of the SPL-Fréjus project revisited

Université Paris-Sud, Laboratoire de l'Accélérateur Linéaire, Bât. 200, 91898, Orsay Cedex, BP 34, France

^* e-mail: campagne@lal.in2p3.fr

Received: 22 November 2004
Revised: 25 October 2005
Published online: 22 December 2005

Abstract

An optimization of the CERN SPL beam line has been performed guided by the sensitivities to the Θ₁₃ mixing angle and to the δ _CP Dirac CP violating phase. A UNO-like 440 ktons water Čerenkov detector located at 130 km from the target in a new foreseen Fréjus laboratory has been used as a generic detector. Concerning the δ _CP independent Θ₁₃ 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.