The earth Mantle-Core effect in charge-asymmetries for atmospheric neutrino oscillations

Bernabéu, J.; Palomares‐Ruiz, Sergio; Perez, A.; Petcov, S.T.

doi:10.1016/s0370-2693(02)01358-8

Cited by 49 publications

(48 citation statements)

References 34 publications

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“…If θ 13 were significantly nonzero, then one could use the presence or absence of the resonance to discern which hierarchy is realized by nature. To do so, one would either need to have a relatively pure neutrino (or antineutrino) source or a detector, such as a magnetized iron calorimeter, which could distinguish neutrino from antineutrino [25,34,35,41,42]. Unfortunately, the atmospheric neutrino and anti-neutrino spectra are roughly equivalent, and water Cerenkov detectors, like Super-K, cannot resolve neutrino from anti-neutrino.…”

mentioning

confidence: 99%

Impact of hierarchy upon the values of neutrino mixing parameters

Escamilla-Roa¹,

Latimer²,

Ernst³

2010

Phys. Rev. C

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A neutrino-oscillation analysis is performed of the more finely binned Super-K atmospheric, MI-NOS, and CHOOZ data in order to examine the impact of neutrino hierarchy in this data set upon the value of θ13 and the deviation of θ23 from maximal mixing. Exact oscillation probabilities are used, thus incorporating all powers of θ13 and ε := θ23 − π/4. The extracted oscillation parameters are found to be dependent on the hierarchy, particularly for θ13. We find at 90% CL are ∆32 = 2.44 +0.26 −0.20 and 2.48 +0.25 −0.22 × 10 −3 eV 2 , ε = θ23 − π/4 = 0.06 +0.06 −0.16 and 0.06 +0.08 −0.17 , and θ13 = −0.07 +0.18 −0.11 and −0.13 +0.23 −0.16 , for the normal and inverted hierarchy respectively. The inverted hierarchy is preferred at a statistically insignificant level of 0.3 σ.PACS numbers: 14.60.Pq Keywords: neutrino oscillations, three neutrinos, mixing angles, mass-squared differences, mass hierarchyThe field of neutrino oscillations has progressed rapidly over the past fifteen years. The data can largely be understood by the oscillation of the three known neutrinos [1, 2]. Oscillation phenomenology invokes a unitary matrix that relates the flavor basis, in which the neutrinos are created or destroyed, to the mass basis, in which the neutrinos propagate through vacuum. This matrix can be written in terms of three real mixing angles, θ 12 , θ 23 , and θ 13 , and a phase δ that determines CP violation. Oscillations also require nonzero neutrino mass differences, being dependent upon the difference of the square of the masses, ∆ ij := m 2 i − m 2 j with m i the mass of neutrino i. A recent analysis [3] reports the present knowledge of the values of the oscillation parameters. In particular, we note that only an upper limit exists on the size of the "reactor" mixing angle |θ 13 | = 0.19 +0.12 −0.19 (1σ), a constraint which arises, in part, from the null oscillation result of the CHOOZ experiment [4]. A nonzero value of θ 13 is requisite for the existence of CP violation in neutrino oscillations; hence, we presently have no knowledge of the value of δ. We also have no knowledge of the ordering of the neutrino mass eigenstate; namely, is m 3 greater or less than m 1 and m 2 ? The former (latter) situation is termed the normal (inverted) hierarchy.Recently, hints of nonzero θ 13 have been reported as a means by which to ease the tension between the determination of the oscillation parameters θ 12 and ∆ 21 by the solar and KamLAND experiments [5,6]. At a smaller significance, analyses of atmospheric data also hint at nonzero θ 13 [7,8], though one study shows that the significance of the results are dependent upon the precise nature of the statistical analysis [9]. Furthermore, an analysis of the updated atmospheric data finds no preference for nonzero θ 13 [10]; however, this analysis employs approximate oscillation formulae and cannot be directly compared to these other works. Should these various hints be cleanly confirmed in current neutrino oscillation experiments [11-13], then one might be able to attack the issue of C...

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confidence: 99%

Impact of hierarchy upon the values of neutrino mixing parameters

Escamilla-Roa¹,

Latimer²,

Ernst³

2010

Phys. Rev. C

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“…We use a Gaussian energy resolution function for the muons as given by Eq. (8). We show the impact of this smearing in Fig.…”

Section: L=12611 Kmmentioning

confidence: 92%

Measuring the mass hierarchy with muon and hadron events in atmospheric neutrino experiments

Ghosh

Choubey

2013

J. High Energ. Phys.

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Neutrino mass hierarchy can be measured in atmospheric neutrino experiments through the observation of earth matter effects. Magnetized iron calorimeters have been shown to be good in this regard due to their charge identification capabilities. The charged current interaction of ν µ in this detector, produces a muon track and a hadron shower. The direction of the muon track can be measured very accurately. We show the improvement expected in the reach of this class of experiments to the neutrino mass hierarchy, as we improve the muon energy resolution and the muon reconstruction efficiency. We next propose to include the hadron events in the analysis, by tagging them with the zenith angle of the corresponding muon and binning the hadron data first in energy and then in zenith angle. To the best of our knowledge this way of performing the analysis of the atmospheric neutrino data has not be considered before. We show that the hadron events increase the mass hierarchy sensitivity of the experiment. Finally, we show the expected mass hierarchy sensitivity in terms of the reconstructed neutrino energy and zenith angle. We show how the detector resolutions spoil the earth matter effects in the neutrino channel and argue why the sensitivity obtained from the neutrino analysis cannot be significantly better than that obtained from the analysis using muon data alone. As a result, the best mass hierarchy sensitivity is obtained when we add the contribution of the muon and the hadron data. For sin 2 2θ 13 = 0.1, sin 2 θ 23 = 0.5, a muon energy resolution of 2%, reconstruction efficiency of 80% and exposure of 50 × 10 kton-year, we could get up to 4.5σ signal for the mass hierarchy from combining the muon and hadron data. The signal will go up when the atmospheric data is combined with data from other existing experiments, particularly NOνA.

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“…[36]). The mixing angle 13 also controls the Earth matter effects in multi-GeV atmospheric [37][38][39][40][41] and in supernova [42] neutrino oscillations.…”

Section: Introductionmentioning

confidence: 99%

“…This should be compared with the sensitivity of the proposed NO A experiment [27]. At 95% C.L., only for less than 40% of the values of , the type of neutrino mass hierarchy can be resolved if 2 Information on the type of neutrino mass hierarchy might be obtained in future atmospheric neutrino experiments [38][39][40][41]. If neutrino are Majorana particles, next generation of neutrinoless double -decay experiments could establish the type of neutrino mass spectrum [44] (see also Refs.…”

Section: Introductionmentioning

confidence: 99%

Determining the neutrino mass hierarchy andCP-violation inNOνAwith a second off-axis detector

2006

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We consider a Super-NO A-like experimental configuration based on the use of two detectors in a long-baseline experiment as NO A. We take the far detector as in the present NO A proposal and add a second detector at a shorter baseline. The location of the second off-axis detector is chosen such that the ratio L=E is the same for both detectors, being L the baseline and E the neutrino energy. We consider liquid argon and water-Č erenkov techniques for the second off-axis detector and study, for different experimental setups, the detector mass required for the determination of the neutrino mass hierarchy, for different values of 13 . We also study the capabilities of such an experimental setup for determining CP-violation in the neutrino sector. Our results show that by adding a second off-axis detector a remarkable enhancement on the capabilities of the current NO A experiment could be achieved.

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The earth Mantle-Core effect in charge-asymmetries for atmospheric neutrino oscillations

Cited by 49 publications

References 34 publications

Impact of hierarchy upon the values of neutrino mixing parameters

Impact of hierarchy upon the values of neutrino mixing parameters

Measuring the mass hierarchy with muon and hadron events in atmospheric neutrino experiments

Determining the neutrino mass hierarchy andCP-violation inNOνAwith a second off-axis detector

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