Three-Neutrino Oscillations of Atmospheric Neutrinos, θ13, Neutrino Mass Hierarchy and Iron Magnetized Detectors
نویسندگان
چکیده
We derive predictions for the Nadir angle (θn) dependence of the ratio Nμ−/Nμ+ of the rates of the μ− and μ+ multi-GeV events, and for the μ−−μ+ event rate asymmetry, Aμ−μ+ = [N(μ −)−N(μ+)]/[N(μ−)+N(μ+)], in iron-magnetized calorimeter detectors (MINOS, INO, etc.) in the case of 3-neutrino oscillations of the atmospheric νμ and ν̄μ, driven by one neutrino mass squared difference, |∆m31| ∼ (2.0−3.0)×10−3 eV2 ≫ ∆m21. The asymmetry Aμ−μ+ (the ratio Nμ−/Nμ+) is shown to be particularly sensitive to the Earth matter effects in the atmospheric neutrino oscillations, and thus to the values of sin θ13 and sin 2 θ23, θ13 and θ23 being the neutrino mixing angle limited by the CHOOZ and Palo Verde experiments and that responsible for the dominant atmospheric νμ → ντ (ν̄μ → ν̄τ ) oscillations. It is also very sensitive to the type of neutrino mass spectrum which can be with normal (∆m31 > 0) or with inverted (∆m31 < 0) hierarchy. We find that for sin 2 θ23 >∼ 0.50, sin 2θ13 >∼ 0.06 and |∆m31| = (2−3)×10−3 eV2, the Earth matter effects produce a relative difference between the integrated asymmetries Āμ−μ+ and Ā 2ν μ−μ+ in the mantle (cos θn = 0.30−0.84) and core (cos θn = 0.84−1.0) bins, which is bigger in absolute value than approximately ∼ 15%, can reach the values of (30− 35)%, and thus can be sufficiently large to be observable. The sign of the indicated asymmetry difference is anticorrelated with the sign of ∆m31. An observation of the Earth matter effects in the Nadir angle distribution of the asymmetry Aμ−μ+ (ratio Nμ−/Nμ+) would clearly indicate that sin 2 2θ13 >∼ 0.06 and sin θ23 >∼ 0.50, and would lead to the determination of the sign of ∆m31. ∗Also at: Institute of Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria.
منابع مشابه
Can We Learn Something More on Oscillations from Atmospheric Neutrinos?
We show that for long-baseline experiments using a Mt water Čerenkov detector atmospheric neutrino data provide a powerful method to resolve parameter degeneracies. In particular, the combination of long-baseline and atmospheric data increases significantly the sensitivity to the neutrino mass hierarchy and the octant of θ23. Furthermore, we discuss the possibility to use μlike atmospheric neut...
متن کاملDetermining the Neutrino Mass Hierarchy with Atmospheric Neutrinos
The possibility to determine the type of neutrino mass hierarchy by studying atmospheric neutrino oscillations with a detector capable to distinguish between neutrino and antineutrino events, such as magnetized iron calorimeters, is considered. We discuss how the ability to distinguish between the neutrino mass spectrum with normal and inverted hierarchy depends on detector characteristics like...
متن کاملPhysics Potential of Future Atmospheric Neutrino Searches
The potential of future high statistics atmospheric neutrino experiments is considered, having in mind currently discussed huge detectors of various technologies (water Cerekov, magnetized iron, liquid Argon). I focus on the possibility to use atmospheric data to determine the octant of θ23 and the neutrino mass hierarchy. The sensitivity to the θ23-octant of atmospheric neutrinos is competitiv...
متن کاملAtmospheric Neutrino Oscillations, θ13 and Neutrino Mass Hierarchy
We derive predictions for the Nadir angle (θn) dependence of the ratio Nμ/Ne of the rates of the μ−like and e−like multi-GeV events measured in water-Čerenkov detectors in the case of 3-neutrino oscillations of the atmospheric νe (ν̄e) and νμ (ν̄μ), driven by one neutrino mass squared difference, |∆m31| ∼ (2.5− 3.0)× 10−3 eV2 ≫ ∆m21. This ratio is particularly sensitive to the Earth matter effect...
متن کاملOn the Atmospheric Neutrino Oscillations, θ13 and Neutrino Mass Hierarchy
We give predictions for the up-down asymmetry in the Nadir angle dependence of the ratio Nμ/Ne of the rates of the μ−like and e−like multi-GeV events measured in water-Čerenkov detectors (Super-Kamiokande, etc.) in the case of 3-neutrino oscillations of the atmospheric νe (ν̄e) and νμ (ν̄μ), driven by one neutrino mass squared difference, |∆matm | ≡ |∆m 2 31| ∼ (2.0 − 3.0) × 10 −3 eV2 ≫ ∆m21 ≡ ∆m...
متن کامل