SearcharxivSearch

arXiv · hep-ph/0209131

Solar Neutrinos: Interpretation of Results

Abstract

Recent SNO results give strong evidence that the solar neutrinos undergo the flavor conversion. Main issue now is the identification of the mechanism of conversion. The LMA MSW solution with $Δm^2 = (5 - 7) \cdot 10^{-5}$ eV$^2$, $\tan^2 θ= 0.35 - 0.45$ looks rather plausible: it fits well the experimental data and our new theoretical prejudices. In the LMA case, KamLAND should see (0.5 - 0.7) reduced signal. VAC-QVO and LOW are accepted at about $3σ$-level. The SMA solution is practically excluded. No sub-leading effects produced by $U_{e3}$ and admixture of sterile neutrino have been found. The fit becomes worse with increase of $U_{e3}$ (for LMA) and the $ν_s$ admixture. Still (30 - 50)% presence of the sterile neutrino is allowed. Solutions based on the neutrino spin-flip in the magnetic fields of the Sun as well as on non-standard neutrino interactions give good fit of the data. If KamLAND confirms LMA MSW, the spin-flip and non-standard interactions can be considered (and will be searched for) as sub-leading effects.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

A. Yu. Smirnov. 2002-09-12. Solar Neutrinos: Interpretation of Results. https://doi.org/10.1016/s0920-5632(03)01307-0

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Axionic Wormholes in Metric-Affine Gravity

The axion is a promising candidate for solving the strong CP problem. To solve this problem, the global U(1) symmetry must be preserved to a high degree of accuracy. However, it is well known that global symmetries are explicitly violated by quantum gravity effects, giving rise to what is referred to as the axion quality problem. In this paper, we investigate axionic wormholes as a source of explicit U(1) violation in Metric-Affine Gravity. This framework allows for spacetime torsion and non-metricity, which accommodate additional curvature-like and topological terms, such as the Holst and Nieh--Yan terms, that are absent from the metric and Palatini formalisms. We show that non-minimal couplings to these terms modify the wormhole dynamics and enhance the Euclidean wormhole action, thereby alleviating the axion quality problem. We also find that the viable parameter space is enlarged when two of these couplings are simultaneously present. We further identify representative parameter regions where the alleviation of the axion quality problem is compatible with inflationary constraints.

hep-ph

Qubit-Qutrit Quantum Tomography of hadronic $\Lambda\phi$ and $\Lambda K^{\ast 0}$ systems

Quantum-information observables have emerged in recent years as new tools in nuclear and particle physics, from entanglement in top-quark pairs to spin correlations in $\Lambda\bar{\Lambda}$ production. Extending these studies to unequal-spin hadronic final states poses a fundamental challenge: the $6\times6$ density matrix of a qubit-qutrit system contains 35 independent spin parameters, but the decays of $\Lambda V$ pairs, with $V=\phi$ or $K^{*0}$, provide access to only 23 due to the hidden vector polarization from the strong decay. In this Letter, we formulate a qubit-qutrit quantum tomography (QQQT) technique for these spin-$\tfrac{1}{2}\otimes1$ systems and establish exact criteria for entanglement certification from the \textit{incomplete} density matrix. Compared with the $\Lambda\bar{\Lambda}$ system, QQQT of $\Lambda\phi$ and $\Lambda K^{*0}$ provides a new probe of nonperturbative QCD hadronization, enabling a direct comparison of the spin evolution of entangled quark pairs produced from the vacuum as they hadronize into a baryon or a vector meson.

hep-ph

Twist decomposition of exclusive heavy meson production cross sections

We study the twist decomposition of the total cross sections for exclusive heavy vector meson electroproduction and photoproduction in the $\gamma^\ast p$ processes, within the leading logarithmic $1/x$ BFKL formalism. The Mellin transforms of the impact factors of the vector meson are calculated. We show that the higher twist contributions are strongly suppressed in the low-$x$ kinematical regime. Possible enhancement of the higher twists effects for nuclei targets is discussed.

hep-ph