NEUTRINO CHARGE RADIUS SQUARED

INSPIRE   PDGID:
S066CRD
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
1995B
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
1989B
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.
References