Model-dependent and -independent implications of the first Sudbury Neutrino Observatory results - art. no. 093007

Citation
Gl. Fogli et al., Model-dependent and -independent implications of the first Sudbury Neutrino Observatory results - art. no. 093007, PHYS REV D, 6409(9), 2001, pp. 3007
Citations number
41
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physics
Journal title
PHYSICAL REVIEW D
ISSN journal
0556-2821 → ACNP
Volume
6409
Issue
9
Year of publication
2001
Database
ISI
SICI code
0556-2821(20011101)6409:9<3007:MA-IOT>2.0.ZU;2-N
Abstract
We briefly discuss some implications of the first solar nu results from the Sudbury Neutrino Observatory (SNO) experiment in the charged-current chann el, We first show that the present SNO response function is very similar to the Super-Karniokancle (SK) one above 8.6 MeV in kinetic electron energy. On the basis of such equivalence we confirm. in a completely model-independ ent way, the SNO evidence for an active. nonelectron neutrino component in the SK event sample, with a significance greater than 3 sigma. Then, by ass uming no oscillations into sterile neutrinos, we combine the SK+SNO data to derive allowed regions for two free parameters: (i) the ratio f(B) of the true B-8 nu flux from the Sun to the corresponding value predicted by the s tandard solar model (SSM), and (ii) the nu (e) survival probability <P-ee>, averaged over the common SK and SNO response function. We obtain the separ ate 3 sigma ranges: f(B) = 1.03(-0.58)(+0.50) (in agreement with the SSM ce ntral value, f(B) = 1) and <P-ee> = 0.34(-0.18)(+0.61)(in > 3 sigma disagre ement with the standard electroweak model prediction, <P-ee> = 1 with stron g anticorrelation between the two parameters. Finally, by taking f(B) and i ts uncertainties as predicted by the SSM, we perform an updated analysis of the 2 nu active neutrino oscillation parameters (deltam(2),tab(2)omega) in cluding all the solar nu data. as well as the spectral data from the CHOOZ reactor experiment. We find that only the solutions at tan(2)omega similar toO(1) survive at the 3 sigma level in the global fit, with a preference fo r the one at high deltam(2)-the so-called large mixing angle solution.