[論文レビュー] Constraints on $f(T)$ Gravity from Solar Neutrino Conversion

H. Yazdani Ahmadabadi, H. Mohseni Sadjadi|arXiv (Cornell University)|Jan 27, 2026

Neutrino Physics Research被引用数 0

ひとこと要約

tldr: f(T) 重力における時空のねじれがニュートリノ味混合振動をどのように修飾するかを解析し、ねじれ誘起の位相シフトと質量平方の補正を導出し、太陽ニュートリノデータを用いてモデルパラメータを制約する。

ABSTRACT

We report new constraints on the parameters of $f(T)$ teleparallel gravity, derived from its imprints on neutrino flavor oscillations. Our analysis reveals that the presence of spacetime torsion can alter both vacuum oscillations and the matter enhanced Mikheyev Smirnov Wolfenstein (MSW) resonance. By using data from solar neutrino experiments: Super-Kamiokande, SNO, Borexino, and KamLAND, we perform a combined analysis to place the first direct observational bounds on the neutrino-torsion coupling and $f(T)$ parameters. These results establish neutrino phenomenology as a novel astrophysical probe for testing fundamental modifications of gravity.

研究の動機と目的

• Investigate whether spacetime torsion modifies neutrino flavor oscillations within f(T) gravity.
• Derive analytical expressions for torsion-induced phase shifts and effective mass-squared differences.
• Assess impacts on vacuum oscillations and MSW resonance in matter under torsion couplings.
• Constrain teleparallel model parameters and neutrino-torsion couplings using solar neutrino data.

提案手法

• Use Dirac action in teleparallel geometry to obtain an effective coupling between torsion vector and neutrino current.
• Work in the weak-field limit around a spherical mass to obtain analytical torsion-induced corrections.
• Derive the modified neutrino oscillation phase and effective mass-squared differences incorporating T1(x).
• Formulate a Schrödinger-like evolution equation with torsion-induced energy shifts and mass corrections.
• Apply a two-flavor approximation for solar neutrinos to obtain modified oscillation parameters in matter.
• Constrain α in f(T)=T+αT^2 and the neutrino-torsion coupling from solar neutrino observations.

実験結果

リサーチクエスチョン

• RQ1 How does torsion in f(T) gravity modify the vacuum oscillation phase of neutrinos?
• RQ2 What are the torsion-induced corrections to neutrino effective mass-squared and energy, and how do they affect oscillations in matter?
• RQ3 How do these corrections alter MSW resonance for solar neutrinos?
• RQ4 What constraints do solar neutrino experiments place on the f(T) gravity parameter α and neutrino-torsion couplings?

主な発見

• Torsion induces a shift in neutrino energy and an energy-dependent correction to the mass-squared differences.
• The oscillation phase acquires a torsion term proportional to the integral of T1(x) along the path, weighted by the coupling difference Δκ(ij).
• Axial torsion contributions vanish for the chosen spherically symmetric tetrad, leaving vector-torsion coupling as the relevant term.
• Inside matter, the effective mass-squared difference becomes Δm^2_m(r)=Δm^2−2EνΔκ(ij)T1(r), modifying the 2-flavor MSW formalism.
• For allowed α values, torsion-induced corrections to Δm^2_31 are negligible compared to the standard vacuum value, preserving the two-flavor approximation for solar neutrinos.
• Solar neutrino data from SK, SNO, Borexino, and KamLAND constrain the teleparallel model parameter α and the neutrino-torsion coupling.