Pragmatic View of Short-Baseline Neutrino Oscillations

Abstract

We present the results of global analyses of short-baseline neutrino oscillation data in 3+1, 3+2 and 3+1+1 neutrino mixing schemes. We show that the data do not allow us to abandon the simplest 3+1 scheme in favor of the more complex 3+2 and 3+1+1 schemes. We present the allowed region in the 3+1 parameter space, which is located at $Δ{m}^2_{41}$ between 0.82 and 2.19 $\text{eV}^2$ at $3σ$. The case of no oscillations is disfavored by about $6σ$, which decreases dramatically to about $2σ$ if the LSND data are not considered. Hence, new high-precision experiments are needed to check the LSND signal.

Figures (3)

• Figure 1: Averaged transition probability in MiniBooNE bins corresponding to the best-fit values of the oscillation parameters in the 3+1-LOW, 3+2-LOW and 3+1+1-LOW fits (see Tabs. \ref{['tab:3p1']} and \ref{['tab:3p2']}) compared with the experimental data.
• Figure 2: Allowed region in the $\sin^{2}2\vartheta_{e\mu}$--$\Delta{m}^{2}_{41}$ plane in the global (GLO) 3+1-HIG fit of short-baseline neutrino oscillation data compared with the $3\sigma$ allowed regions obtained from $\hbox{$$ {\overset{(-)}{ }}} {{\nu}_{\mu}}\to\hbox{$$ {\overset{(-)}{ }}} {{\nu}_{e}}$ short-baseline appearance data (APP; inside the solid blue curves) and the $3\sigma$ constraints obtained from $\hbox{$$ {\overset{(-)}{ }}} {{\nu}_{e}}$ short-baseline disappearance data ($\nu_{e}$ DIS; left of the dotted dark-red curve), $\hbox{$$ {\overset{(-)}{ }}} {{\nu}_{\mu}}$ short-baseline disappearance data ($\nu_{\mu}$ DIS; left of the dash-dotted dark-green curve) and the combined short-baseline disappearance data (DIS; left of the dashed red curve). The best-fit points of the GLO and APP fits are indicated by crosses.
• Figure 3: Allowed regions in the $\sin^{2}2\vartheta_{ee}$--$\Delta{m}^{2}_{41}$ and $\sin^{2}2\vartheta_{\mu\mu}$--$\Delta{m}^{2}_{41}$ planes in the global (GLO) 3+1-HIG fit of short-baseline neutrino oscillation data compared with the $3\sigma$ constraints obtained from $\hbox{$$ {\overset{(-)}{ }}} {{\nu}_{e}}$ short-baseline disappearance data (solid red DIS curve in the left panel), $\hbox{$$ {\overset{(-)}{ }}} {{\nu}_{\mu}}$ short-baseline disappearance data (solid red DIS curve in the right panel). The best-fit point of the GLO fit is indicated by crosses.