A very intense neutrino super beam experiment for leptonic CP violation discovery based on the European spallation source linac

Abstract

Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few µs with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 σ significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 σ if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.

Revisiting the quantum decoherence scenario as an explanation for the LSND anomaly

“…The situation is similar also for other short baseline neutrino experiment proposals with neutrino energies few × 100 MeV, see e.g., [49,50]. For the ESS superbeam [51,52], with a peak energy of E 200 MeV some decoherence effects may start to show up if the E 1,3 parameters are not too small. We do predict an appearance signal in LSND-like short baseline experiments with energies around 30 MeV; see e.g., [53].…”

ESSnuSB Neutrino Oscillation Project

“…In this context, the ESSνSB collaboration [2] proposes to take benefit from the European Spallation Source currently under construction at Lund in Sweden to produce a very intense neutrino superbeam.…”

Searching for sterile neutrinos at the ESSνSB

“…Overall, global analyses show strong tension between different data sets [16][17][18] and further experimental input will be needed to clarify the situation. The European Spallation Source ν-Beam [19,20] (ESSνSB) is a proposal for a neutrino oscillation experiment based upon the accelerator facilities of the future European Spallation Source (ESS) and optimized for the goal of a high significance search for CP violation. The relatively large value of θ 13 recently discovered [21][22][23][24][25] guarantees a comparatively high signal, which implies that the bottleneck of CP violation searches for the next generation of neutrino oscillation facilities will typically be systematics errors rather than statistics or backgrounds.…”