A comparative study of long-baseline superbeams within LAGUNA for large $θ_{13}$

Abstract

The Daya Bay and RENO experiments have recently observed a non-zero θ 13 at more than 5σ CL. This has important consequences for future neutrino oscillation experiments. We analyze these within the LAGUNA design study which considers seven possible locations for a European neutrino observatory for proton decay, neutrino, and astroparticle physics. The megaton-scale detector would be an ideal target for a CERN-based neutrino beam with baselines ranging from 130 km to 2300 km. We perform a detailed study to assess the physics reach of the three detector options -a 440 kton water Čerenkov, a 100 kton liquid argon and a 50 kton liquid scintillator detector -at each of the possible locations, taking into account the recent measurement of θ 13 . We study the impact of the beam properties and detector performances on the sensitivity to CPviolation and the mass hierarchy. We find that a liquid argon or water Čerenkov detector can make a 3σ discovery of CP violation for 60% − 70% of the parameter space for any of the baselines under consideration, although the results for the liquid argon detector placed at 130 km are slightly worse and only 40% − 50% is achieved in this case. The performance of the liquid scintillator detector is affected by its level of neutral-current background at all baselines. A 3σ determination of the mass hierarchy is possible for all values of δ, for the values of θ 13 favoured at 3σ by Daya Bay and RENO, for almost all setups with L 650 km.

Non-standard interaction effect on $CP$ violation in neutrino oscillation with super-beam

“…So with only SM the short baseline like 130 Km seems to be better for good discovery reach of CP violation. This was observed earlier by different authors [13][14][15][16][17]. However, the short baseline may not be always better in presence of NSI which we discuss below.…”

“…In figures 1, 2, 3 we have shown the NSI effect ∆ p in the particular oscillation channel ν µ → ν e (which is the most important channel for CP violation discovery) for different baseline length L and different neutrino energy E. It is found that oscillation probability P νµ→νe changes significantly in presence of NSI ε eµ and ε eτ in comparison to other NSIs for longer baselines and higher energies. It is known that in presence of SM interactions of neutrinos with matter the shorter baseline can give better discovery reach for CP violation [13][14][15][16][17]. However, as we have shown that in presence of NSI this may not be always true.…”

“…We do a comparative study in the discovery potentials of the CP violating phase δ for these two baselines in presence of both standard and non-standard interactions. There are some earlier studies for short and long baselines for standard interactions [10][11][12][13][14][15][16][17] for neutrinos coming from superbeam. Also there are such studies in presence of non-standard interactions [18,19] before Daya Bay experiment when θ 13 was not so precisely known.…”

Comparison of the calorimetric and kinematic methods of neutrino energy reconstruction in disappearance experiments

“…Phenomenological analyses for wide-band neutrino beams operating in the multi-GeV energy regime have shown that the sensitivity to neutrino oscillation parameters of a liquid-argon detector is similar to that of a Cherenkov detector of the mass ∼3-6 times larger, because of the lower efficiency of the latter for non-QE events [57,[80][81][82][83]. It has been argued that the reason lies in the imaging capabilities of the liquid-argon technology, able to identify protons in addition to lepton tracks [57], as opposed to Cherenkov detectors in which the information on CC events comes predominantly from the charged leptons.…”

Determination of the θ 23 octant in LBNO

“…In this work we assume the following detecting properties [23,24]. Whenever a neutrino interacts with the detector substance, the counting system reconstructs the energy and flavor of the incident neutrino and identifies the event with the corresponding energy bin.…”