Speaker
Description
The European Spallation Source neutrino Super Beam (ESSνSB) is a long-baseline neutrino project that will measure the CP-violation (CPV) in the leptonic sector at the second, rather than the first, $\nu_{μ}$ to $\nu_{e}$, oscillation maximum, where the sensitivity is $\sim$ 3 times higher. The use of the 5 MW proton beam of the ESS linac combined to a $\sim$ 3 cubic-km Water Cherenkov detector located at the second oscillation maximum paves the way to a precise measurement of the CPV phase, $\delta_{CP}$. The ESS$\nu$SB Conceptual Design Report showed that that after 10 years of data taking, more than 70$\%$ of the possible $\delta_{CP}$ range will be covered with 5$\sigma$ C.L. to reject the no-CP-violation hypothesis. The expected value of $\delta_{CP}$ precision is smaller than 8$^{\circ}$ for all $\delta_{CP}$ values, making it the most precise proposed experiment in the field by a large margin. The next phase of the project, the ESSνSB+, which has been started in Jan. 2023, for a 4-year design study program, aims in using the intense muon flux produced together with neutrinos to measure the neutrino-nucleus cross-section (the dominant term of the systematic uncertainty) in the energy range of 0.2 – 0.6 GeV, using a Low Energy nuSTORM (LEnuSTORM) and a Low Energy Monitored Neutrino Beam (LEMNB) facilities.
In this talk, an overview of successfully concluded design-study of the experiment and its physics reach will be presented. Moreover, the recently accepted, by the Horizon-Europe program, extension project, the ESS$\nu$SB+, will be also presented.
