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

Abstract

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.

Synergies between the first-generation JHF-SK and NuMI superbeam experiments

“…All results within this work are, unless otherwise stated, calculated for the current best-fit values of the atmospheric [62,63] and solar neutrino experiments [6]. The ranges are, at the 3σ confidence level, given by…”

“…For the case of higher energies, the event rates, scaling ∝ E 3+x , would be increased. 6 For the case of shorter baselines, the rates simply scale ∝ 1/L 2 . Thus, any of the two options would lead to higher event rates for an experiment optimized for a larger value of |∆m 2 31 |.…”

Constraining neutrino oscillation parameters with current solar and atmospheric data

“…Since the release of the latest SNO data in April 2002 a number of global solar neutrino analyses in terms of active oscillations appeared [9,25,26,27,28,29,30,31]. Moreover, it has been shown by model-independent comparisons of the SNO CC rate with the SNO NC and Super-K rates that transitions of solar neutrinos into sterile neutrinos are strongly constrained by the recent data (see, e.g., Refs.…”

Tomography of the Earth's core using supernova neutrinos

“…For the neutrino oscillation parameters we choose θ 12 = 32.9 • , θ 13 = 5 • , θ 23 = 45 • , ∆m 2 21 = 5.0 · 10 −5 eV 2 , ∆m 2 32 = 2.5 · 10 −3 eV 2 , and δ CP = 0 [54,55,56,57,58], i.e., a normal mass hierarchy. Matter effects on supernova neutrinos in the Earth are discussed in detail in Ref.…”