  Very intense neutrino beams and large neutrino detectors will be needed to
enable the discovery of CP violation in the leptonic sector. The European
Spallation Source (ESS), currently under construction in Lund, Sweden, is a
research center that will provide, by 2023, the world's most powerful neutron
source. The average power will be 5 MW. Pulsing this linac at higher frequency,
at the same instantaneous power, will make it possible to raise the average
beam power to 10 MW to produce, in parallel with the spallation neutron
production, a high performance neutrino Super Beam of about 0.4 GeV mean
neutrino energy. The ESS neutrino Super Beam, ESSnuSB, operated with a 2.0 GeV
linac proton beam, together with a large underground Water Cherenkov detector
located at 540 km from Lund, close to the second oscillation maximum, will make
it possible to discover leptonic CP violation at 5 sigma significance level in
56 percent (65 percent for an upgrade to 2.5 GeV beam energy) of the leptonic
Dirac CP-violating phase range after 10 years of data taking. The paper gives
an overview of the proposed facility and presents the outstanding physics reach
possible for CP violation with ESSnuSB.
