Assuming a light right-handed neutrino, except for BEALL 1982, LANGACKER 1989B, and COLANGELO 1991. ${{\mathit g}_{{{R}}}}$ = ${{\mathit g}_{{{L}}}}$ assumed. [Limits in the section MASS LIMITS for ${{\mathit W}^{\,'}}$ below are also valid for ${{\mathit W}_{{{R}}}}$ if ${\mathit m}_{{{\mathit \nu}_{{{R}}}}}{}\ll$ ${\mathit m}_{{{\mathit W}_{{{R}}}}}$.] Some limits assume manifest left-right symmetry, $\mathit i.e.$, the equality of left- and right Cabibbo-Kobayashi-Maskawa matrices. For a comprehensive review, see LANGACKER 1989B. Limits on the ${{\mathit W}_{{{L}}}}-{{\mathit W}_{{{R}}}}$ mixing angle $\zeta $ are found in the next section. Values in brackets are from cosmological and astrophysical considerations and assume a light right-handed neutrino.

VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT $> 592$ 90 1 BUENO 2011 TWST ${{\mathit \mu}}$ decay $\bf{>715}$ 90 2 CZAKON 1999 RVUE Electroweak • • We do not use the following data for averages, fits, limits, etc. • • $>235$ 90 3 PRIEELS 2014 PIE3 ${{\mathit \mu}}$ decay $> 245$ 90 4 WAUTERS 2010 CNTR ${}^{60}\mathrm {Co}{{\mathit \beta}}$ decay $> 2500$ 5 ZHANG 2008 THEO ${\mathit m}_{{{\mathit K}_L^0} }−{\mathit m}_{{{\mathit K}_S^0} }$ $> 180$ 90 6 MELCONIAN 2007 CNTR ${}^{37}\mathrm {K}{{\mathit \beta}^{+}}$ decay $> 290.7$ 90 7 SCHUMANN 2007 CNTR Polarized neutron decay $\text{[> 3300]}$ 95 8 CYBURT 2005 COSM Nucleosynthesis; light ${{\mathit \nu}_{{{R}}}}$ $>310$ 90 9 THOMAS 2001 CNTR ${{\mathit \beta}^{+}}$ decay $>137$ 95 10 ACKERSTAFF 1999 D OPAL ${{\mathit \tau}}$ decay $>1400$ 68 11 BARENBOIM 1998 RVUE Electroweak, ${{\mathit Z}}-{{\mathit Z}^{\,'}}$ mixing $>549$ 68 12 BARENBOIM 1997 RVUE ${{\mathit \mu}}$ decay $>220$ 95 13 STAHL 1997 RVUE ${{\mathit \tau}}$ decay $>220$ 90 14 ALLET 1996 CNTR ${{\mathit \beta}^{+}}$ decay $>281$ 90 15 KUZNETSOV 1995 CNTR Polarized neutron decay $>282$ 90 16 KUZNETSOV 1994 B CNTR Polarized neutron decay $>439$ 90 17 BHATTACHARYYA 1993 RVUE ${{\mathit Z}}-{{\mathit Z}^{\,'}}$ mixing $>250$ 90 18 SEVERIJNS 1993 CNTR ${{\mathit \beta}^{+}}$ decay 19 IMAZATO 1992 CNTR ${{\mathit K}^{+}}$ decay $>475$ 90 20 POLAK 1992 B RVUE ${{\mathit \mu}}$ decay $>240$ 90 21 AQUINO 1991 RVUE Neutron decay $>496$ 90 21 AQUINO 1991 RVUE Neutron and muon decay $>700$ 22 COLANGELO 1991 THEO ${\mathit m}_{{{\mathit K}_L^0} }–{\mathit m}_{{{\mathit K}_S^0} }$ $>477$ 90 23 POLAK 1991 RVUE ${{\mathit \mu}}$ decay $\text{[none 540 - 23000]}$ 24 BARBIERI 1989 B ASTR SN 1987A; light ${{\mathit \nu}_{{{R}}}}$ $>300$ 90 25 LANGACKER 1989 B RVUE General $>160$ 90 26 BALKE 1988 CNTR ${{\mathit \mu}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \nu}}{{\overline{\mathit \nu}}}$ $>406$ 90 27 JODIDIO 1986 ELEC Any $\zeta $ $>482$ 90 27 JODIDIO 1986 ELEC $\zeta $ = 0 $>800$ MOHAPATRA 1986 RVUE SU(2)$_{\mathit L}{\times }SU(2)_{\mathit R}{\times }$U(1) $>400$ 95 28 STOKER 1985 ELEC Any $\zeta $ $>475$ 95 28 STOKER 1985 ELEC $\zeta $ $<$0.041 29 BERGSMA 1983 CHRM ${{\mathit \nu}_{{{\mu}}}}$ ${{\mathit e}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \nu}_{{{e}}}}$ $>380$ 90 30 CARR 1983 ELEC ${{\mathit \mu}^{+}}$ decay $>1600$ 31 BEALL 1982 THEO ${\mathit m}_{{{\mathit K}_L^0} }–{\mathit m}_{{{\mathit K}_S^0} }$ 1  The quoted limit is for manifest left-right symmetric model. 2  CZAKON 1999 perform a simultaneous fit to charged and neutral sectors. 3  PRIEELS 2014 limit is from ${{\mathit \mu}^{+}}$ $\rightarrow$ ${{\mathit e}^{+}}{{\mathit \nu}}{{\overline{\mathit \nu}}}$ decay parameter ${{\mathit \xi}^{''}}$, which is determined by the positron polarization measurement. 4  WAUTERS 2010 limit is from a measurement of the asymmetry parameter of polarized ${}^{60}\mathrm {Co}{{\mathit \beta}}$ decays. The listed limit assumes no mixing. 5  ZHANG 2008 limit uses a lattice QCD calculation of the relevant hadronic matrix elements, while BEALL 1982 limit used the vacuum saturation approximation. 6  MELCONIAN 2007 measure the neutrino angular asymmetry in ${{\mathit \beta}^{+}}$-decays of polarized ${}^{37}\mathrm {K}$, stored in a magneto-optical trap. Result is consistent with SM prediction and does not constrain the ${{\mathit W}_{{{L}}}}$ ${{\mathit W}_{{{R}}}}$ mixing angle appreciably. 7  SCHUMANN 2007 limit is from measurements of the asymmetry $\langle \overrightarrow{{\mathit p}}_{{{\mathit \nu}}}\cdot{}{{\mathit \sigma}_{{{n}}}}\rangle $ in the $\beta $ decay of polarized neutrons. Zero mixing is assumed. 8  CYBURT 2005 limit follows by requiring that three light ${{\mathit \nu}_{{{R}}}}$'s decouple when ${{\mathit T}_{{{{dec}}}}}$ $>$ 140 MeV. For different ${{\mathit T}_{{{{dec}}}}}$, the bound becomes ${{\mathit M}}_{{{\mathit W}_{{{R}}}}}$ $>$ 3.3 TeV (${{\mathit T}_{{{{dec}}}}}$ $/$ 140 MeV)${}^{3/4}$. 9  THOMAS 2001 limit is from measurement of ${{\mathit \beta}^{+}}$ polarization in decay of polarized ${}^{12}\mathrm {N}$. The listed limit assumes no mixing. 10  ACKERSTAFF 1999D limit is from ${{\mathit \tau}}$ decay parameters. Limit increase to 145 GeV for zero mixing. 11  BARENBOIM 1998 assumes minimal left-right model with Higgs of SU(2)$_{\mathit R}$ in SU(2)$_{\mathit L}$ doublet. For Higgs in SU(2)$_{\mathit L}$ triplet, ${\mathit m}_{{{\mathit W}_{{{R}}}}}>$1100 GeV. Bound calculated from effect of corresponding ${{\mathit Z}_{{{LR}}}}$ on electroweak data through ${{\mathit Z}}-{{\mathit Z}_{{{LR}}}}$ mixing. 12  The quoted limit is from ${{\mathit \mu}}$ decay parameters. BARENBOIM 1997 also evaluate limit from ${{\mathit K}_{{{L}}}}-{{\mathit K}_{{{S}}}}$ mass difference. 13  STAHL 1997 limit is from fit to ${{\mathit \tau}}$-decay parameters. 14  ALLET 1996 measured polarization-asymmetry correlation in ${}^{12}\mathrm {N}$ ${{\mathit \beta}^{+}}$ decay. The listed limit assumes zero $\mathit L-\mathit R$ mixing. 15  KUZNETSOV 1995 limit is from measurements of the asymmetry $\langle{}\overrightarrow{{\mathit p}}_{{{\mathit \nu}}}\cdot{}{{\mathit \sigma}_{{{n}}}}\rangle{}$ in the $\beta $ decay of polarized neutrons. Zero mixing assumed. See also KUZNETSOV 1994B. 16  KUZNETSOV 1994B limit is from measurements of the asymmetry $\langle{}\overrightarrow{{\mathit p}}_{{{\mathit \nu}}}\cdot{}{{\mathit \sigma}_{{{n}}}}\rangle{}$ in the $\beta $ decay of polarized neutrons. Zero mixing assumed. 17  BHATTACHARYYA 1993 uses ${{\mathit Z}}-{{\mathit Z}^{\,'}}$ mixing limit from LEP '90 data, assuming a specific Higgs sector of SU(2)$_{\mathit L}{\times }SU(2)_{\mathit R}{\times }$U(1) gauge model. The limit is for ${\mathit m}_{{{\mathit t}}}$=200 GeV and slightly improves for smaller ${\mathit m}_{{{\mathit t}}}$. 18  SEVERIJNS 1993 measured polarization-asymmetry correlation in ${}^{107}\mathrm {In}$ ${{\mathit \beta}^{+}}$ decay. The listed limit assumes zero ${{\mathit L}}-{{\mathit R}}$ mixing. Value quoted here is from SEVERIJNS 1994 erratum. 19  IMAZATO 1992 measure positron asymmetry in ${{\mathit K}^{+}}$ $\rightarrow$ ${{\mathit \mu}^{+}}{{\mathit \nu}_{{{\mu}}}}$ decay and obtain $\xi {{\mathit P}_{{{\mu}}}}>0.990$ (90$\%$ CL). If ${{\mathit W}_{{{R}}}}$ couples to ${{\mathit u}}{{\overline{\mathit s}}}$ with full weak strength ($\mathit V{}^{\mathit R}_{{{\mathit u}} {{\mathit s}}}$=1), the result corresponds to ${\mathit m}_{{{\mathit W}_{{{R}}}}}>$653 GeV. See their Fig.$~$4 for ${\mathit m}_{{{\mathit W}_{{{R}}}}}$ limits for general $\vert \mathit V{}^{\mathit R}_{{{\mathit u}} {{\mathit s}}}\vert ^2=1−\vert \mathit V{}^{\mathit R}_{{{\mathit u}} {{\mathit d}}}\vert ^2$. 20  POLAK 1992B limit is from fit to muon decay parameters and is essentially determined by JODIDIO 1986 data assuming $\zeta $=0. Supersedes POLAK 1991. 21  AQUINO 1991 limits obtained from neutron lifetime and asymmetries together with unitarity of the CKM matrix. Manifest left-right symmetry assumed. Stronger of the two limits also includes muon decay results. 22  COLANGELO 1991 limit uses hadronic matrix elements evaluated by QCD sum rule and is less restrictive than BEALL 1982 limit which uses vacuum saturation approximation. Manifest left-right symmetry assumed. 23  POLAK 1991 limit is from fit to muon decay parameters and is essentially determined by JODIDIO 1986 data assuming $\zeta $=0. Superseded by POLAK 1992B. 24  BARBIERI 1989B limit holds for ${\mathit m}_{{{\mathit \nu}_{{{R}}}}}{}\leq{}$10 MeV. 25  LANGACKER 1989B limit is for any ${{\mathit \nu}_{{{R}}}}$ mass (either Dirac or Majorana) and for a general class of right-handed quark mixing matrices. 26  BALKE 1988 limit is for ${\mathit m}_{\mathrm {{{\mathit \nu}}_{{{\mathit e}} {{\mathit R}}}}}$ = 0 and ${\mathit m}_{\mathrm {{{\mathit \nu}}_{{{\mathit \mu}} {{\mathit R}}}}}{}\leq{}$ 50 MeV. Limits come from precise measurements of the muon decay asymmetry as a function of the positron energy. 27  JODIDIO 1986 is the same TRIUMF experiment as STOKER 1985 (and CARR 1983); however, it uses a different technique. The results given here are combined results of the two techniques. The technique here involves precise measurement of the end-point ${{\mathit e}^{+}}$ spectrum in the decay of the highly polarized ${{\mathit \mu}^{+}}$. 28  STOKER 1985 is same TRIUMF experiment as CARR 1983. Here they measure the decay ${{\mathit e}^{+}}$ spectrum asymmetry above 46 ${\mathrm {MeV}}/\mathit c$ using a muon-spin-rotation technique. Assumed a light right-handed neutrino. Quoted limits are from combining with CARR 1983. 29  BERGSMA 1983 set limit ${\mathit m}_{{{\mathit W}_{{{2}}}}}/{\mathit m}_{{{\mathit W}_{{{1}}}}}$ $>$1.9 at CL = 90$\%$. 30  CARR 1983 is TRIUMF experiment with a highly polarized ${{\mathit \mu}^{+}}$ beam. Looked for deviation from $\mathit V−\mathit A$ at the high momentum end of the decay ${{\mathit e}^{+}}$ energy spectrum. Limit from previous world-average muon polarization parameter is ${\mathit m}_{{{\mathit W}_{{{R}}}}}$ $>$240 GeV. Assumes a light right-handed neutrino. 31  BEALL 1982 limit is obtained assuming that ${{\mathit W}_{{{R}}}}$ contribution to ${{\mathit K}_L^0}$ $-{{\mathit K}_S^0}$ mass difference is smaller than the standard one, neglecting the top quark contributions. Manifest left-right symmetry assumed.

References