The dark side of the solar neutrino parameter space

Gouvêa, André de; Friedland, Alexander; Murayama, Hitoshi

doi:10.1016/s0370-2693(00)00989-8

Cited by 121 publications

(58 citation statements)

References 14 publications

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“…, this is equivalent to inquiring about the sign of cos 2θ 12 , or whether the solar angle is in the light or the dark-side of the parameter space [11]. * As a matter of fact, the magnitude of x should be small enough so that both ∆m where X ≡ x/2E and, for simplicity, we have dropped the '+' superscript in ∆m 2+ 13 .…”

Section: A How To Compare a Normal And An Inverted Mass-hierarchymentioning

confidence: 99%

Neutrino mass hierarchy, vacuum oscillations, and vanishing|Ue3|

2005

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Is the relatively isolated member of the neutrino mass spectrum heavier or lighter than the two closely-spaced members? This question -the character of the neutrino mass hierarchy -is of great theoretical interest. All previously identified experiments for addressing it via neutrino oscillations require that the currently unknown size of the Ue3 element of the leptonic mixing matrix (parameterized by the unknown θ13 mixing angle) be sufficiently large, and will utterly fail in the limit θ13 → 0. For this reason, we explore alternative oscillation approaches that would still succeed even if θ13 vanishes. We identify several alternatives that require neither a nonzero |Ue3| nor the presence of significant matter effects. All include multiple percent-level neutrino oscillation measurements, usually involving muon-neutrino (or antineutrino) disappearance and very long baselines. We comment on the degree of promise that these alternative approaches show.

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Section: A How To Compare a Normal And An Inverted Mass-hierarchymentioning

confidence: 99%

Neutrino mass hierarchy, vacuum oscillations, and vanishing|Ue3|

2005

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“…We follow refs. [31,32] in using tan 2 θ (rather than sin 2 2θ) in order to display conveniently the solutions on both sides of θ = π/4. Figure 1a presents the result for our standard analysis, (a), the free 8 B analysis.…”

Section: Global Oscillation Solutionsmentioning

confidence: 99%

Before and After: How has the SNO NC measurement changed things?

Bahcall¹,

González-García²,

Peña-Garay³

2002

J. High Energy Phys.

126

121

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We present "Before and After" global oscillation solutions, as well as predicted "Before and After" values and ranges for ten future solar neutrino observables (for BOREXINO, KamLAND, SNO, and a generic p − p neutrino detector). The "Before" case includes all solar neutrino data (and some theoretical improvements) available prior to April 20, 2002 and the "After" case includes, in addition, the new SNO data on the CC, NC, and day-night asymmetry. We have performed global analyses using the full SNO day-night energy spectrum and, alternatively, using just the SNO NC and CC rates and the day-night asymmetry. The LMA solution is the only currently allowed MSW oscillation solution at ∼ 99% CL. The LOW solution is allowed only at more than 2.5σ, SMA is now excluded at 3.7σ or 4.7σ depending upon analysis strategy, and pure sterile oscillations are excluded at more than 4.7σ. Small mixing angles are "out" (pure sterile is "way out"); MSW with large mixing angles is definitely "in." Vacuum oscillations are allowed at 3σ, but not at 2σ. Precise maximal mixing is excluded at 3.2σ for MSW solutions and at more than 2.8σ for vacuum solutions. Most of the predicted values for future observables for the BOREXINO, KamLAND, and future SNO measurements are changed only by minor amounts by the inclusion of the recent SNO data. In order to test the robustness of the allowed neutrino oscillation regions that are inferred from the measurements and the predicted values for future solar neutrino observables, we have carried out calculations using a variety of strategies for analyzing the SNO and other experimental data.

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“…We follow refs. [28,29] in using tan 2 θ (rather than sin 2 2θ) in order to display conveniently solutions on both sides of θ = π/4. Figure 1a presents the result for our standard analysis, which includes the BP00 predicted fluxes and uncertainties and all the experimental data except the Super- The three different analysis strategies are described in section 3.3.…”

Section: Global Oscillation Solution: Three Different Analysesmentioning

confidence: 99%

Robust signatures of solar neutrino oscillation solutions

Bahcall

González-García

Peña-Garay

2002

J. High Energy Phys.

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With the goal of identifying signatures that select specific neutrino oscillation parameters, we test the robustness of global oscillation solutions that fit all the available solar and reactor experimental data. We use three global analysis strategies previously applied by different authors and also determine the sensitivity of the oscillation solutions to the critical nuclear fusion cross section, S 17 (0), for the production of 8 B. Our standard results make use of the precise new measurement of S 17 (0) by Junghans et al. The globally favored solutions are, in order of goodness of fit: LMA(the only solution at 2σ), LOW, and VAC. The NC to CC ratio for SNO is predicted by the standard global analysis to be 3.45 +0.70 −0.54 (1σ) which is separated from the no-oscillation value of 1.0 by much more than the expected experimental error. The predicted range of the day-night difference in CC rates is 8.3 +5.0 −5.6 (1σ)%. A measurement by SNO of either a NC to CC ratio > 3.3 or a day-night difference > 10%, would favor a small region of the currently allowed LMA neutrino parameter space. The global oscillation solution predicts a 7 Be neutrino-electron scattering rate in BOREXINO and KamLAND in the range 0.65 +0.04 −0.03 (1σ) of the BP00 standard solar model rate, a prediction which can be used to test both the solar model and the neutrino oscillation theory. Only the LOW solution predicts a large day-night effect(≤ 42%, 3σ) in BOREXINO and KamLAND. For the reactor KamLAND experiment, the LMA solution predicts a charged current rate relative to the standard model of 0.44 +0.22 −0.07 (1σ), E threshold = 1.22 MeV. We have also evaluated the effects of including preliminary Super-Kamiokande data for 1496 days of observations.

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The dark side of the solar neutrino parameter space

Cited by 121 publications

References 14 publications

Neutrino mass hierarchy, vacuum oscillations, and vanishing|Ue3|

Neutrino mass hierarchy, vacuum oscillations, and vanishing|Ue3|

Before and After: How has the SNO NC measurement changed things?

Robust signatures of solar neutrino oscillation solutions

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