#### (C) Other neutrino mixing results

The LSND collaboration reported in AGUILAR 2001 a signal which is consistent with ${{\overline{\mathit \nu}}_{{\mu}}}$ $\rightarrow$ ${{\overline{\mathit \nu}}_{{e}}}$ oscillations. In a three neutrino framework, this would be a measurement of $\theta _{12}$ and $\Delta \mathit m{}^{2}_{21}$. This does not appear to be consistent with most of the other neutrino data. The following listings include results from ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ , ${{\overline{\mathit \nu}}_{{\mu}}}$ $\rightarrow$ ${{\overline{\mathit \nu}}_{{e}}}$ appearance and ${{\mathit \nu}_{{\mu}}}$ , ${{\overline{\mathit \nu}}_{{\mu}}}$ , ${{\mathit \nu}_{{e}}}$ , and ${{\overline{\mathit \nu}}_{{e}}}$ disappearance experiments, and searches for $\mathit CPT$ violation.

#### $\Delta \mathit m{}^{2}$ for sin$^2(2{}\theta )$ = 1 ( ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ )

VALUE (eV${}^{2}$) CL% DOCUMENT ID TECN  COMMENT
• • We do not use the following data for averages, fits, limits, etc. • •
$0.03\text{ to }0.55$ 90 1
 2021
MBNE MiniBooNE ${{\mathit \nu}}$ ,${{\overline{\mathit \nu}}}$ combined
$0.03\text{ to }0.05$ 90 2
 2018 C
MBNE MiniBooNE ${{\mathit \nu}}$ ,${{\overline{\mathit \nu}}}$ combined
$0.015\text{ to }0.050$ 90 3
 2013 A
MBNE MiniBooNE
$<0.34$ 90 4
 2012
MBNE MiniBooNE/SciBooNE
$<0.034$ 90
 2007
MBNE MiniBooNE
$<0.0008$ 90
 2004
K2K Water Cherenkov
$<0.4$ 90
 2003
NOMD CERN SPS
$<2.4$ 90
 2002
NTEV NUTEV FNAL
5
 2001
LSND ${{\mathit \nu}}$ ${{\mathit \mu}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ osc.prob.
$0.03\text{ to }0.3$ 95 6
 1998
LSND ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$
$<2.3$ 90 7
 1996
CHARM/CDHS
$<0.9$ 90
 1994 C
CHM2 CERN SPS
$<0.09$ 90
 1986
HLBC BEBC CERN PS
 1 AGUILAR-AREVALO 2021 result is based on a total of $18.75 \times 10^{20}$ POT in neutrino mode, and $11.27 \times 10^{20}$ POT in anti-neutrino mode. Best fit at 0.043 eV${}^{2}$. The allowed region does not extend to large $\Delta$m${}^{2}$. The quoted value is the entire allowed region of $\Delta$m${}^{2}$ at 90$\%$ C.L. for all values of sin$^2(2\theta )$. Supersedes AGUILAR-AREVALO 2018C.
 2 AGUILAR-AREVALO 2018C result is based on ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ appearance of $460.5$ $\pm99.0$ events; The best fit value is $\Delta$m${}^{2}$ = 0.041 eV${}^{2}$. Superseded by AGUILAR-AREVALO 2021 .
 3 AGUILAR-AREVALO 2013A result is based on ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ appearance of $162.0$ $\pm47.8$ events; marginally compatible with twoneutrino oscillations. The best fit value is $\Delta$m${}^{2}$ = 3.14 eV${}^{2}$.
 4 MAHN 2012 is a combined spectral fit of MiniBooNE and SciBooNE neutrino data with the range of $\Delta$m${}^{2}$ up to 25 eV${}^{2}$. The best limit is 0.04 at 7 eV${}^{2}$.
 5 AGUILAR 2001 is the final analysis of the LSND full data set. Search is made for the ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ oscillations using ${{\mathit \nu}_{{\mu}}}$ from ${{\mathit \pi}^{+}}$ decay in flight by observing beam-on electron events from ${{\mathit \nu}_{{e}}}$ ${}^{}\mathrm {C}$ $\rightarrow$ ${{\mathit e}^{-}}{{\mathit X}}$ . Present analysis results in $8.1$ $\pm12.2$ $\pm1.7$ excess events in the 60$<\mathit E_{{{\mathit e}} }<200$ MeV energy range, corresponding to oscillation probability of $0.10$ $\pm0.16$ $\pm0.04\%$. This is consistent, though less significant, with the previous result of ATHANASSOPOULOS 1998 , which it supersedes. The present analysis uses selection criteria developed for the decay at rest region, and is less effective in removing the background above 60 MeV than ATHANASSOPOULOS 1998 .
 6 ATHANASSOPOULOS 1998 is a search for the ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ oscillations using ${{\mathit \nu}_{{\mu}}}$ from ${{\mathit \pi}^{+}}$ decay in flight. The 40 observed beam-on electron events are consistent with ${{\mathit \nu}_{{e}}}$ ${}^{}\mathrm {C}$ $\rightarrow$ ${{\mathit e}^{-}}$ X; the expected background is $21.9$ $\pm2.1$. Authors interpret this excess as evidence for an oscillation signal corresponding to oscillations with probability ($0.26$ $\pm0.10$ $\pm0.05)\%$. Although the significance is only $2.3~\sigma$, this measurement is an important and consistent cross check of ATHANASSOPOULOS 1996 who reported evidence for ${{\overline{\mathit \nu}}_{{\mu}}}$ $\rightarrow$ ${{\overline{\mathit \nu}}_{{e}}}$ oscillations from ${{\mathit \mu}^{+}}$ decay at rest. See also ATHANASSOPOULOS 1998B.
 7 LOVERRE 1996 uses the charged-current to neutral-current ratio from the combined CHARM (ALLABY 1986 ) and CDHS (ABRAMOWICZ 1986 ) data from 1986.
References:
 AGUILAR-AREVALO 2021
PR D103 052002 Updated MiniBooNE neutrino oscillation results with increased data and new background studies
 AGUILAR-AREVALO 2018C
PRL 121 221801 Significant Excess of ElectronLike Events in the MiniBooNE Short-Baseline Neutrino Experiment
 AGUILAR-AREVALO 2013A
PRL 110 161801 Improved Search for ${{\overline{\mathit \nu}}_{{\mu}}}$ $\leftrightarrow{{\overline{\mathit \nu}}_{{e}}}$ Oscillations in the MiniBooNE Experiment
 MAHN 2012
PR D85 032007 Dual Baseline Search for Muon Neutrino Disappearance at 0.5 eV${}^{2}$ < $\Delta$m${}^{2}$ < 40 eV${}^{2}$
 AGUILAR-AREVALO 2007
PRL 98 231801 Search for Electron Neutrino Appearance at the $\Delta \mathit m{}^{2}\sim{}$1 eV${}^{2}$ Scale
 AHN 2004
PRL 93 051801 Search for Electron Neutrino Appearance in 250 km Long-baseline Experiment
 ASTIER 2003
PL B570 19 Search for ${{\mathit \nu}_{{\mu}}}$ $\rightarrow$ ${{\mathit \nu}_{{e}}}$ Oscillations in the NOMAD Experiment
 AVVAKUMOV 2002
PRL 89 011804 A Search for ${{\mathit \nu}_{{\mu}}}$ $-{{\mathit \nu}_{{e}}}$ and ${{\overline{\mathit \nu}}_{{\mu}}}$ $-{{\overline{\mathit \nu}}_{{e}}}$ Oscillations at NUTeV
 AGUILAR 2001
PR D64 112007 Evidence for Neutrino Oscillations from the Observation of ${{\overline{\mathit \nu}}_{{e}}}$ Appearance in a ${{\overline{\mathit \nu}}_{{\mu}}}$ Beam
 ATHANASSOPOULOS 1998
PRL 81 1774 Evidence for ${{\mathit \nu}_{{\mu}}}$ $\leftrightarrow$ ${{\mathit \nu}_{{e}}}$ Oscillations from the LSND
 LOVERRE 1996
PL B370 156 Limits on ${{\mathit \nu}_{{\mu}}}$ Oscillations from the Measurement of the Ratio of 0${{\mathit \mu}^{\pm}}$ to 1${{\mathit \mu}^{\pm}}$ Events at the CERN Narrow Band Neutrino Beam
 VILAIN 1994C
ZPHY C64 539 Search for Muon to Electron Neutrino Oscillations
 ANGELINI 1986
PL B179 307 New Experimental Limits on ${{\mathit \nu}_{{\mu}}}$ $\leftrightarrow$ ${{\mathit \nu}_{{e}}}$ Oscillations