37 research outputs found
Neutrino mass and mixing parameters: A short review
We present a brief review of the current status of neutrino mass and mixing
parameters, based on a comprehensive phenomenological analysis of neutrino
oscillation and non-oscillation searches, within the standard three-neutrino
mixing framework.Comment: 11 pages, including 7 figures. Presented at the 40th Rencontres de
Moriond on Electroweak Interactions and Unified Theories, La Thuile, Aosta
Valley, Italy, 5-12 Mar 200
Evidence of theta(13)>0 from global neutrino data analysis
The neutrino mixing angle theta(13) is at the focus of current neutrino
research. From a global analysis of the available oscillation data in a
3-neutrino framework, we previously reported [Phys. Rev. Lett. 101, 141801
(2008)] hints in favor of theta(13)>0 at the 90 % C.L. Such hints are
consistent with the recent indications of nu(mu)-->nu(e) appearance in the T2K
and MINOS long-baseline accelerator experiments. Our global analysis of all the
available data currently provides >3 sigma evidence for nonzero theta(13), with
1-sigma ranges sin^2 theta(13) = 0.021+-0.007 or 0.025+-0.007, depending on
reactor neutrino flux systematics. Updated ranges are also reported for the
other 3-neutrino oscillation parameters (delta m^2, sin^2 theta(12)) and (Delta
m^2, sin^2 theta(23)).Comment: Slightly revised text; results unchanged. To appear in Phys. Rev.
Observables sensitive to absolute neutrino masses. II
In this followup to Phys. Rev. D 75, 053001 (2007) [arXiv:hep-ph/0608060] we
report updated constraints on neutrino mass-mixing parameters, in light of
recent neutrino oscillation data (KamLAND, SNO, and MINOS) and cosmological
observations (WMAP 5-year and other data). We discuss their interplay with the
final 0nu2beta decay results in 76-Ge claimed by part of the Heidelberg-Moscow
Collaboration, using recent evaluations of the corresponding nuclear matrix
elements, and their uncertainties. We also comment on the 0nu2beta limits in
130-Te recently set by Cuoricino, and on prospective limits or signals from the
KATRIN experiment.Comment: Final version for PRD. Includes one more cosmological dataset
(CMB+LSS) in Table II and in Fig. 3. Title slightly changed in journa
Hints of theta_13>0 from global neutrino data analysis
Nailing down the unknown neutrino mixing angle theta_13 is one of the most
important goals in current lepton physics. In this context, we perform a global
analysis of neutrino oscillation data, focusing on theta_13, and including
recent results [Neutrino 2008, Proceedings of the XXIII International
Conference on Neutrino Physics and Astrophysics, Christchurch, New Zealand,
2008 (unpublished)]. We discuss two converging hints of theta_13>0, each at the
level of ~1sigma: an older one coming from atmospheric neutrino data, and a
newer one coming from the combination of solar and long-baseline reactor
neutrino data. Their combination provides the global estimate sin^2(theta_13) =
0.016 +- 0.010 (1sigma), implying a preference for \theta_13>0 with
non-negligible statistical significance (~90% C.L.). We discuss possible
refinements of the experimental data analyses, which might sharpen such
intriguing indication.Comment: Minor changes in the text. Matches published version in PR
Golden Ratio Prediction for Solar Neutrino Mixing
It has recently been speculated that the solar neutrino mixing angle is
connected to the golden ratio phi. Two such proposals have been made, cot
theta_{12} = phi and cos theta_{12} = phi/2. We compare these Ansatze and
discuss a model leading to cos theta_{12} = phi/2 based on the dihedral group
D_{10}. This symmetry is a natural candidate because the angle in the
expression cos theta_{12} = phi/2 is simply pi/5, or 36 degrees. This is the
exterior angle of a decagon and D_{10} is its rotational symmetry group. We
also estimate radiative corrections to the golden ratio predictions.Comment: 15 pages, 1 figure. Matches published versio
Global analysis of neutrino masses, mixings and phases: entering the era of leptonic CP violation searches
We perform a global analysis of neutrino oscillation data, including
high-precision measurements of the neutrino mixing angle theta_13 at reactor
experiments, which have confirmed previous indications in favor of theta_13>0.
Recent data presented at the Neutrino 2012 Conference are also included. We
focus on the correlations between theta_13 and the mixing angle theta_23, as
well as between theta_13 and the neutrino CP-violation phase delta. We find
interesting indications for theta_23< pi/4 and possible hints for delta ~ pi,
with no significant difference between normal and inverted mass hierarchy.Comment: Updated version, including recent data released at the Neutrino 2012
Conference. Some references adde
Where we are on : addendum to "Global neutrino data and recent reactor fluxes: status of three-flavour oscillation parameters"
In this addendum to arXiv:1103.0734 we consider the recent results from
long-baseline searches at the T2K and MINOS experiments and
investigate their implications for the mixing angle and the
leptonic Dirac CP phase . By combining the indication for a
non-zero value of coming from T2K data with global neutrino
oscillation data we obtain a significance for of about
with best fit points for normal
(inverted) neutrino mass ordering. These results depend somewhat on assumptions
concerning the analysis of reactor neutrino data.Comment: 5 pages, 2 figures and 1 tabl
Three-flavor solar neutrino oscillations with terrestrial neutrino constraints
We present an updated analysis of the current solar neutrino data in terms of
three-flavor oscillations, including the additional constraints coming from
terrestrial neutrino oscillation searches at the CHOOZ (reactor),
Super-Kamiokande (atmospheric), and KEK-to-Kamioka (accelerator) experiments.
The best fit is reached for the subcase of two-family mixing, and the
additional admixture with the third neutrino is severely limited. We discuss
the relevant features of the globally allowed regions in the oscillation
parameter space, as well as their impact on the amplitude of possible
CP-violation effects at future accelerator experiments and on the
reconstruction accuracy of the mass-mixing oscillation parameters at the
KamLAND reactor experiment.Comment: 10 pages + 8 figure
Three-flavour neutrino oscillation update
We review the present status of three-flavour neutrino oscillations, taking
into account the latest available neutrino oscillation data presented at the
Neutrino 2008 Conference. This includes the data released this summer by the
MINOS collaboration, the data of the neutral current counter phase of the SNO
solar neutrino experiment, as well as the latest KamLAND and Borexino data. We
give the updated determinations of the leading 'solar' and 'atmospheric'
oscillation parameters. We find from global data that the mixing angle
is consistent with zero within and we derive an upper
bound of at 90% CL (3).Comment: 17 pages, 7 figures. An appendix is added providing three-neutrino
parameter determinations as of February 2010. We include all oscillation
data, such as the first MINOS electron neutrino appearance data, the low
energy threshold analysis given by the SNO Collaboration, as well as recently
updated Standard Solar Model
Solar neutrino oscillation parameters after first KamLAND results
We analyze the energy spectrum of reactor neutrino events recently observed
in the Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND) and combine
them with solar and terrestrial neutrino data, in the context of two- and
three-family active neutrino oscillations. In the 2-neutrino case, we find that
the solution to the solar neutrino problem at large mixing angle (LMA) is
basically split into two sub-regions, that we denote as LMA-I and LMA-II. The
LMA-I solution, characterized by lower values of the squared neutrino mass gap,
is favored by the global data fit. This picture is not significantly modified
in the 3-neutrino mixing case. A brief discussion is given about the
discrimination of the LMA-I and LMA-II solutions with future KamLAND data. In
both the 2- and 3-neutrino cases, we present a detailed analysis of the
post-KamLAND bounds on the oscillation parameters.Comment: Revised version. Two figures adde