We report limits on the so-called neutrino charge radius squared. While the straight-forward definition of a neutrino charge radius has been proven to be gauge-dependent and, hence, unphysical (LEE 1977C), there have been recent attempts to define a physically observable neutrino charge radius (BERNABEU 2000, BERNABEU 2002). The issue is still controversial (FUJIKAWA 2003, BERNABEU 2003). A more general interpretation of the experimental results is that they are limits on certain nonstandard contributions to neutrino scattering.

VALUE ($ 10^{-32} $ cm${}^{2}$) CL% DOCUMENT ID TECN  COMMENT $\bf{-2.1\text{ to }3.3 }$ 90 1 DENIZ 2010 TEXO Reactor ${{\overline{\mathit \nu}}_{{{e}}}}{{\mathit e}}$ • • We do not use the following data for averages, fits, limits, etc. • • $-27.5\text{ to }3 $ 90 2 CADEDDU 2018 ${{\mathit \nu}_{{{\mu}}}}$ coherent scat. on ${}^{}\mathrm {CsI}$ $-0.53\text{ to }0.68 $ 90 3 HIRSCH 2003 ${{\mathit \nu}_{{{\mu}}}}{{\mathit e}}$ scat. $-8.2\text{ to }9.9 $ 90 4 HIRSCH 2003 anomalous ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\mathit \nu}}{{\overline{\mathit \nu}}}{{\mathit \gamma}}$ $-2.97\text{ to }4.14 $ 90 5 AUERBACH 2001 LSND ${{\mathit \nu}_{{{e}}}}$ ${{\mathit e}}$ $\rightarrow$ ${{\mathit \nu}_{{{e}}}}{{\mathit e}}$ $-0.6\text{ to }0.6 $ 90 VILAIN 1995 B CHM2 ${{\mathit \nu}_{{{\mu}}}}{{\mathit e}}$ elastic scat. $0.9$ $\pm2.7$ ALLEN 1993 CNTR LAMPF ${{\mathit \nu}}$ ${{\mathit e}}$ $\rightarrow$ ${{\mathit \nu}}{{\mathit e}}$ $<2.3$ 95 MOURAO 1992 ASTR HOME/KAM2 ${{\mathit \nu}}$ rates $<7.3$ 90 6 VIDYAKIN 1992 CNTR Reactor ${{\overline{\mathit \nu}}}$ ${{\mathit e}}$ $\rightarrow$ ${{\overline{\mathit \nu}}}{{\mathit e}}$ $1.1$ $\pm2.3$ ALLEN 1991 CNTR Repl. by ALLEN 1993 $-1.1$ $\pm1.0$ 7 AHRENS 1990 CNTR ${{\mathit \nu}_{{{\mu}}}}{{\mathit e}}$ elastic scat. $-0.3$ $\pm1.5$ 7 DORENBOSCH 1989 CHRM ${{\mathit \nu}_{{{\mu}}}}{{\mathit e}}$ elastic scat. 8 GRIFOLS 1989 B ASTR SN 1987A 1  DENIZ 2010 observe reactor ${{\overline{\mathit \nu}}_{{{e}}}}{{\mathit e}}$ scattering with recoil kinetic energies $3 - 8$ MeV using CsI(Tl) detectors. The observed rate and spectral shape are consistent with the Standard Model prediction, leading to the reported constraint on ${{\overline{\mathit \nu}}_{{{e}}}}$ charge radius. 2  CADEDDU 2018 use the data of the COHERENT experiment, AKIMOV 2018. The limit is $\langle $r${}^{2}_{{{\mathit \nu}}}\rangle $ for ${{\mathit \nu}_{{{\mu}}}}$ obtained from the time-dependent data. Weaker limits were obtained for charge radii of ${{\mathit \nu}_{{{e}}}}$ and for transition charge radii. The published value was divided by 2 to conform to the convention of this table. 3  Based on analysis of CCFR 98 results. Limit is on $\langle $r${}^{2}_{V}\rangle $ + $\langle $r${}^{2}_{A}\rangle $. The CHARM II and E734 at BNL results are reanalyzed, and weaker bounds on the charge radius squared than previously published are obtained. The NuTeV result is discussed; when tentatively interpreted as ${{\mathit \nu}_{{{\mu}}}}$ charge radius it implies $\langle $r${}^{2}_{V}\rangle $ + $\langle $r${}^{2}_{A}\rangle $ = ($4.20$ $\pm1.64$) ${\times }$ 10 ${}^{-33}$ cm${}^{2}$. 4  Results of LEP-2 are interpreted as limits on the axial-vector charge radius squared of a Majorana ${{\mathit \nu}_{{{\tau}}}}$. Slightly weaker limits for both vector and axial-vector charge radius squared are obtained for the Dirac case, and somewhat weaker limits are obtained from the analysis of lower energy data (LEP-1.5 and TRISTAN). 5  AUERBACH 2001 measure ${{\mathit \nu}_{{{e}}}}{{\mathit e}}$ elastic scattering with LSND detector. The cross section agrees with the Standard Model expectation, including the charge and neutral current interference. The 90$\%$ CL applies to the range shown. 6  VIDYAKIN 1992 limit is from a ${{\mathit e}}{{\overline{\mathit \nu}}}$ elastic scattering experiment. No experimental details are given except for the cross section from which this limit is derived. Signal/noise was 1/10. The limit uses sin$^2\theta _{\mathit W}$ = $0.23$ as input. 7  Result is obtained from reanalysis given in ALLEN 1991, followed by our reduction to obtain 1$~\sigma $ errors. 8  GRIFOLS 1989B sets a limit of $\langle \mathit r{}^{2}\rangle $ $<~0.2 \times 10^{-32}~$cm${}^{2}$ for right-handed neutrinos.

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