93 research outputs found

    Complementarity Between Hyperkamiokande and DUNE in Determining Neutrino Oscillation Parameters

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    In this work we investigate the sensitivity to the neutrino mass hierarchy, the octant of the mixing angle θ23\theta_{23} and the CP phase δCP\delta_{CP} in the future long-baseline experiments T2HK and DUNE as well as in the atmospheric neutrino observation at Hyperkamiokande (HK). We show for the first time that the sensitivity is enhanced greatly if we combine these three experiments. Our results show that the hierarchy sensitivity of both T2HK and HK are limited due to the presence of parameter degeneracy. But this degeneracy is removed when T2HK and HK are added together. With T2HK+HK (DUNE), the neutrino mass hierarchy can be determined at least at 5σ 5 \sigma (8 σ\sigma) C.L. for any value of true δCP\delta_{CP}. With T2HK+HK+DUNE the significance of the mass hierarchy increases to almost 15 σ\sigma for the unfavorable value of δCP\delta_{CP}. For these combined setup, octant can be resolved except 43.5<θ23<4843.5^\circ < \theta_{23} < 48^\circ at 5σ5\sigma C.L for both the hierarchies irrespective of the value of δCP\delta_{CP}. The significance of CP violation is around 10 σ\sigma C.L. for δCP±90\delta_{CP} \sim \pm 90^\circ. Apart from that these combined facility has the capability to discover CP violation for at least 68%68\% fraction of the true δCP\delta_{CP} values at 5σ5 \sigma for any value of true θ23\theta_{23}. We also find that, with combination of all these three, the precision of Δmeff2\Delta m^2_{{\rm eff}}, sin2θ23\sin^2\theta_{23} and δCP\delta_{CP} becomes 0.3%, 2% and 20% respectively. We also clarify how the octant degeneracy occurs in the HK atmospheric neutrino experiment.Comment: 28 pages, 11 figures, 2 tables, Version accepted for publication in Nucl. Phys.

    A hybrid setup for fundamental unknowns in neutrino oscillations using T2HK (ν\nu) and μ\mu-DAR (νˉ\bar{\nu})

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    Neutrino mass hierarchy, CP-violation, and octant of θ23\theta_{23} are the fundamental unknowns in neutrino oscillations. In order to address all these three unknowns, we study the physics reach of a setup, where we replace the antineutrino run of T2HK with antineutrinos from muon decay at rest (μ\mu-DAR). This approach has the advantages of having higher statistics in both neutrino and antineutrino modes, and lower beam-on backgrounds for antineutrino run with reduced systematics. We find that a hybrid setup consisting of T2HK (ν\nu) and μ\mu-DAR (νˉ\bar\nu) in conjunction with full exposure from T2K and NOν\nuA can resolve the issue of mass hierarchy at greater than 3σ\sigma C.L. irrespective of the choices of hierarchy, δCP\delta_{\mathrm{CP}}, and θ23\theta_{23}. This hybrid setup can also establish the CP-violation at 5σ\sigma C.L. for \sim 55% choices of δCP\delta_{\mathrm{CP}}, whereas the same for conventional T2HK (ν+νˉ\nu + \bar\nu) setup along with T2K and NOν\nuA is around 30%. As far as the octant of θ23\theta_{23} is concerned, this hybrid setup can exclude the wrong octant at 5σ\sigma C.L. if θ23\theta_{23} is at least 33^{\circ} away from maximal mixing for any δCP\delta_{\mathrm{CP}}.Comment: 18 pages, 28 pdf figures, 1 table. Minor changes in the text. A new footnote added. Accepted in JHE

    Synergies between neutrino oscillation experiments: An `adequate' configuration for LBNO

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    Determination of the neutrino mass hierarchy, octant of the mixing angle theta_{23} and the CP violating phase delta_{CP} are the unsolved problems in neutrino oscillation physics today. In this paper our aim is to obtain the minimum exposure required for the proposed Long Baseline Neutrino Oscillation (LBNO) experiment to determine the above unknowns. We emphasize on the advantage of exploiting the synergies offered by the existing and upcoming long-baseline and atmospheric neutrino experiments in economising the LBNO configuration. In particular, we do a combined analysis for LBNO, T2K, NOvA and INO. We consider three prospective LBNO setups -- CERN-Pyhasalmi (2290 km), CERN-Slanic (1500 km) and CERN-Frejus (130 km) and evaluate the adequate exposure required in each case. Our analysis shows that the exposure required from LBNO can be reduced considerably due to the synergies arising from the inclusion of the other experiments.Comment: 22 pages, 14 figures, 2 tables Version published in JHE