# ${{\widetilde{\boldsymbol \nu}}}$ (Sneutrino) mass limit INSPIRE search

The limits may depend on the number, $\mathit N({{\widetilde{\mathit \nu}}}$), of sneutrinos assumed to be degenerate in mass. Only ${{\widetilde{\mathit \nu}}_{{L}}}$ (not ${{\widetilde{\mathit \nu}}_{{R}}}$) is assumed to exist. It is possible that ${{\widetilde{\mathit \nu}}}$ could be the lightest supersymmetric particle (LSP).

We report here, but do not include in the Listings, the limits obtained from the fit of the final results obtained by the LEP Collaborations on the invisible width of the ${{\mathit Z}}~$boson ($\Delta \Gamma _{{\mathrm {inv.}}}<2.0$ MeV, LEP-SLC 2006 ): ${\mathit m}_{{{\widetilde{\mathit \nu}}}}>43.7$ GeV ($\mathit N({{\widetilde{\mathit \nu}}}$)=1) and ${\mathit m}_{{{\widetilde{\mathit \nu}}}}>44.7$ GeV ($\mathit N({{\widetilde{\mathit \nu}}}$)=3) .

Some earlier papers are now obsolete and have been omitted. They were last listed in our PDG 2014 edition: K. Olive, $\mathit et~al.$ (Particle Data Group), Chinese Physics C38 070001 (2014) (http://pdg.lbl.gov).

VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$\bf{> 3400}$ 95 1
 2018 CM
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit \lambda}_{{312}}}$ = ${{\mathit \lambda}_{{321}}}$ = 0.07, ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.11
$> 2900$ 95 2
 2018 CM
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \lambda}_{{313}}}$ = ${{\mathit \lambda}_{{331}}}$ = 0.07, ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.11
$> 2600$ 95 3
 2018 CM
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \tau}}$ , ${{\mathit \lambda}_{{323}}}$ = ${{\mathit \lambda}_{{332}}}$ = 0.07, ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.11
$> 1060$ 95 4
 2018 Z
ATLS RPV,${}\geq{}4{{\mathit \ell}}$, ${{\mathit \lambda}_{{12k}}}{}\not=$0, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 600 GeV (mass-degenerate left-handed sleptons and sneutrinos of all 3 generations)
$> 780$ 95 4
 2018 Z
ATLS RPV,${}\geq{}4{{\mathit \ell}}$, ${{\mathit \lambda}_{{i33}}}{}\not=$0, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 300 GeV (mass-degenerate left-handed sleptons and sneutrinos of all 3 generations)
$> 1700$ 95 5
 2018 AT
CMS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit \lambda}_{{132}}}$ = ${{\mathit \lambda}_{{231}}}$ = ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.01
$> 3800$ 95 5
 2018 AT
CMS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit \lambda}_{{132}}}$ = ${{\mathit \lambda}_{{231}}}$ = ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.1
$> 2300$ 95 6
 2016 P
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.11
$> 2200$ 95 6
 2016 P
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.11
$>1900$ 95 6
 2016 P
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \tau}}$ , ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.11
$> 400$ 95 7
 2014 X
ATLS RPV, ${}\geq{}4{{\mathit \ell}^{\pm}}$, ${{\widetilde{\mathit \nu}}}$ $\rightarrow$ ${{\mathit \nu}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\mp}}{{\mathit \nu}}$
8
 2011 Z
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$
$\bf{>94}$ 95 9
 2003 M
DLPH 1${}\leq{}$tan $\beta {}\leq{}$40, ${\mathit m}_{{{\widetilde{\mathit e}}_{{R}}}}\text{-}{\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}>$10~GeV
$>84$ 95 10
 2002 N
ALEP ${{\widetilde{\mathit \nu}}_{{e}}}$, any $\Delta \mathit m$
$\bf{>41}$ 95 11
 1992
ALEP $\Gamma\mathrm {( {{\mathit Z}} \rightarrow invisible)}$; $\mathit N({{\widetilde{\mathit \nu}}}$)=3, model independent
• • • We do not use the following data for averages, fits, limits, etc. • • •
12
 2019 AO
RPV, ${{\mathit \mu}^{\pm}}{{\mathit \mu}^{\pm}}$ + ${}\geq{}$2jets, ${{\mathit \lambda}_{{211}}^{\,'}}{}\not=$0, ${{\widetilde{\mathit \nu}}_{{\mu}}}$ $\rightarrow$ ${{\mathit \mu}}{{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ , ${{\widetilde{\mathit \chi}}_{{1}}^{\pm}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit q}}{{\overline{\mathit q}}}{{\mathit q}}{{\overline{\mathit q}}}$
$> 1280$ 95 13
 2016 BE
CMS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit \lambda}_{{132}}}$ = ${{\mathit \lambda}_{{231}}}$ = ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.01
$> 2300$ 95 13
 2016 BE
CMS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit \lambda}_{{132}}}$ = ${{\mathit \lambda}_{{231}}}$ = 0.07, ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.11
$>2000$ 95 14
 2015 O
ATLS RPV ( ${{\mathit e}}{{\mathit \mu}}$ ), ${{\widetilde{\mathit \nu}}_{{\tau}}}$, $\lambda {}^{'}_{311}$ = 0.11, $\lambda _{i3k}$ = 0.07
$>1700$ 95 14
 2015 O
ATLS RPV ( ${{\mathit \tau}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ ), ${{\widetilde{\mathit \nu}}_{{\tau}}}$, $\lambda {}^{'}_{311}$ = 0.11, $\lambda _{i3k}$ = 0.07
15
 2013 AI
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \mu}}{{\mathit \tau}}$
16
 2011 H
ATLS RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$
17
 2010 Z
CDF RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \mu}}{{\mathit \tau}}$
18
 2010 M
D0 RPV, ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$
$> 95$ 95 19
 2004 H
DLPH AMSB, ${{\mathit \mu}}$ $>$ 0
$>37.1$ 95 20
 1993 M
L3 $\Gamma\mathrm {( {{\mathit Z}} \rightarrow invisible)}$; $\mathit N({{\widetilde{\mathit \nu}}}$)=1
$>36$ 95
 1991 F
DLPH $\Gamma\mathrm {( {{\mathit Z}} \rightarrow invisible)}$; $\mathit N({{\widetilde{\mathit \nu}}}$)=1
$>31.2$ 95 21
 1991 F
OPAL $\Gamma\mathrm {( {{\mathit Z}} \rightarrow invisible)}$; $\mathit N({{\widetilde{\mathit \nu}}}$)=1
1  AABOUD 2018CM searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for heavy particles decaying into an ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \mu}}{{\mathit \tau}}$ final state. No significant deviation from the expected SM background is observed. Limits are set on the mass of a stau neutrino with R-parity-violating couplings. For ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , masses below 3.4 TeV are excluded at 95$\%$ CL, see their Figure 4(b). Upper limits on the RPV couplings $\vert {{\mathit \lambda}_{{312}}}\vert$ versus $\vert {{\mathit \lambda}_{{311}}^{\,'}}\vert$ are also performed, see their Figure 8(a-b).
2  AABOUD 2018CM searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for heavy particles decaying into an ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \mu}}{{\mathit \tau}}$ final state. No significant deviation from the expected SM background is observed. Limits are set on the mass of a stau neutrino with R-parity-violating couplings. For ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \tau}}$ , masses below 2.9 TeV are excluded at 95$\%$ CL, see their Figure 5(b). Upper limits on the RPV couplings $\vert {{\mathit \lambda}_{{313}}}\vert$ versus $\vert {{\mathit \lambda}_{{311}}^{\,'}}\vert$ are also performed, see their Figure 8(c).
3  AABOUD 2018CM searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for heavy particles decaying into an ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \mu}}{{\mathit \tau}}$ final state. No significant deviation from the expected SM background is observed. Limits are set on the mass of a stau neutrino with R-parity-violating couplings. For ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit \mu}}{{\mathit \tau}}$ , masses below 2.6 TeV are excluded at 95$\%$ CL, see their Figure 6(b). Upper limits on the RPV couplings $\vert {{\mathit \lambda}_{{323}}}\vert$ versus $\vert {{\mathit \lambda}_{{311}}^{\,'}}\vert$ are also performed, see their Figure 8(d).
4  AABOUD 2018Z searched in 36.1 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for events containing four or more charged leptons (electrons, muons and up to two hadronically decaying taus). No significant deviation from the expected SM background is observed. Limits are set on the Higgsino mass in simplified models of general gauge mediated supersymmetry Tn1n1A/Tn1n1B/Tn1n1C, see their Figure 9. Limits are also set on the wino, slepton, sneutrino and gluino mass in a simplified model of NLSP pair production with R-parity violating decays of the LSP via ${{\mathit \lambda}_{{12k}}}$ or ${{\mathit \lambda}_{{i33}}}$ to charged leptons, see their Figures 7, 8.
5  SIRUNYAN 2018AT searched in 35.9 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for heavy resonances decaying into ${{\mathit e}}{{\mathit \mu}}$ final states. No significant excess above the Standard Model expectation is observed and 95$\%$ C.L. exclusions are placed on the cross section times branching ratio for the R-parity-violating production and decay of a supersymmetric tau sneutrino, see their Fig. 3.
6  AABOUD 2016P searched in 3.2 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for events with different flavour dilepton pairs ( ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ , ${{\mathit \mu}}{{\mathit \tau}}$ ) from the production of ${{\widetilde{\mathit \nu}}_{{\tau}}}$ via an RPV ${{\mathit \lambda}_{{311}}^{\,'}}$ coupling and followed by a decay via ${{\mathit \lambda}_{{312}}}$ = ${{\mathit \lambda}_{{321}}}$ = 0.07 for ${{\mathit e}}{+}$ ${{\mathit \mu}}$ , via ${{\mathit \lambda}_{{313}}}$ = ${{\mathit \lambda}_{{331}}}$ = 0.07 for ${{\mathit e}}{+}$ ${{\mathit \tau}}$ and via ${{\mathit \lambda}_{{323}}}$ = ${{\mathit \lambda}_{{332}}}$ = 0.07 for ${{\mathit \mu}}{+}$ ${{\mathit \tau}}$ . No evidence for a dilepton resonance over the SM expectation is observed, and limits are derived on ${\mathit m}_{{{\widetilde{\mathit \nu}}}}$ at 95$\%$ CL, see their Figs. 2(b), 3(b), 4(b), and Table 3.
7  AAD 2014X searched in 20.3 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for events with at least four leptons (electrons, muons, taus) in the final state. No significant excess above the Standard Model expectations is observed. Limits are set on the sneutrino mass in an R-parity violating simplified model where the decay ${{\widetilde{\mathit \nu}}}$ $\rightarrow$ ${{\mathit \nu}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , with ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\mp}}{{\mathit \nu}}$ , takes place with a branching ratio of 100$\%$, see Fig. 9.
8  AAD 2011Z looked in 1.07 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events with one electron and one muon of opposite charge from the production of ${{\widetilde{\mathit \nu}}_{{\tau}}}$ via an RPV ${{\mathit \lambda}^{\,'}}_{311}$ coupling and followed by a decay via ${{\mathit \lambda}}_{312}$ into ${{\mathit e}}{+}$ ${{\mathit \mu}}$ . No evidence for an (${{\mathit e}}$, ${{\mathit \mu}}$) resonance over the SM expectation is observed, and a limit is derived in the plane of ${{\mathit \lambda}^{\,'}}_{311}$ versus ${\mathit m}_{{{\widetilde{\mathit \nu}}}}$ for three values of ${{\mathit \lambda}}_{312}$, see their Fig. 2. Masses ${\mathit m}_{{{\widetilde{\mathit \nu}}}}$ $<$ 1.32 (1.45) TeV are excluded for ${{\mathit \lambda}^{\,'}}_{311}$ = 0.10 and ${{\mathit \lambda}}_{312}$ = 0.05 (${{\mathit \lambda}^{\,'}}_{311}$ = 0.11 and ${{\mathit \lambda}}_{312}$ = 0.07).
9  ABDALLAH 2003M uses data from $\sqrt {s }$ = $192 - 208$ GeV to obtain limits in the framework of the MSSM with gaugino and sfermion mass universality at the GUT scale. An indirect limit on the mass is derived by constraining the MSSM parameter space by the results from direct searches for neutralinos (including cascade decays) and for sleptons. These limits are valid for values of M$_{2}<$ 1 TeV, $\vert {{\mathit \mu}}\vert {}\leq{}$1 TeV with the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ as LSP. The quoted limit is obtained when there is no mixing in the third family. See Fig.~43 for the mass limits as a function of tan $\beta$. These limits update the results of ABREU 2000W.
10  HEISTER 2002N derives a bound on ${\mathit m}_{{{\widetilde{\mathit \nu}}_{{e}}}}$ by exploiting the mass relation between the ${{\widetilde{\mathit \nu}}_{{e}}}$ and ${{\widetilde{\mathit e}}}$, based on the assumption of universal GUT scale gaugino and scalar masses $\mathit m_{1/2}$ and $\mathit m_{0}$ and the search described in the ${{\widetilde{\mathit e}}}$ section. In the MSUGRA framework with radiative electroweak symmetry breaking, the limit improves to ${\mathit m}_{{{\widetilde{\mathit \nu}}_{{e}}}}>$130 GeV, assuming a trilinear coupling $\mathit A_{0}$=0 at the GUT scale. See Figs.$~$5 and 7 for the dependence of the limits on tan $\beta$.
11  DECAMP 1992 limit is from $\Gamma\mathrm {({\mathrm {invisible}})}/\Gamma\mathrm {( {{\mathit \ell}} {{\mathit \ell}} )}$ = $5.91$ $\pm0.15$ ($\mathit N_{{{\mathit \nu}}}$ = $2.97$ $\pm0.07$).
12  SIRUNYAN 2019AO searched in 35.9 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for events containing two same-sign muons and at last two jets, originating from resonant production of second-generation sleptons (${{\widetilde{\mathit \mu}}_{{L}}}$, ${{\widetilde{\mathit \nu}}_{{\mu}}}$) via the R-parity violating coupling ${{\mathit \lambda}_{{211}}^{\,'}}$ to quarks. No significant excess above the Standard Model expectations is observed. Upper limits on cross sections are derived in the context of two simplified models, see their Figure 4. The cross section limits are translated into limits on ${{\mathit \lambda}_{{211}}^{\,'}}$ for a modified CMSSM, see their Figure 5.
13  KHACHATRYAN 2016BE searched in 19.7 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for evidence of narrow resonances decaying into ${{\mathit e}}{{\mathit \mu}}$ final states. No significant excess above the Standard Model expectation is observed and 95$\%$ C.L. exclusions are placed on the cross section times branching ratio for the production of an R-parity-violating supersymmetric tau sneutrino, see their Fig. 3.
14  AAD 2015O searched in 20.3 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for evidence of heavy particles decaying into ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ or ${{\mathit \mu}}{{\mathit \tau}}$ final states. No significant excess above the Standard Model expectation is observed, and 95$\%$ C.L. exclusions are placed on the cross section times branching ratio for the production of an $\mathit R$-parity-violating supersymmetric tau sneutrino, applicable to any sneutrino flavour, see their Fig. 2.
15  AAD 2013AI searched in 4.6 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for evidence of heavy particles decaying into ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ or ${{\mathit \mu}}{{\mathit \tau}}$ final states. No significant excess above the Standard Model expectation is observed, and 95$\%$ C.L. exclusions are placed on the cross section times branching ratio for the production of an R-parity-violating supersymmetric tau sneutrino, see their Fig. 2. For couplings ${{\mathit \lambda}^{\,'}}_{311}$ = 0.10 and ${{\mathit \lambda}_{{i3k}}}$ = 0.05, the lower limits on the ${{\widetilde{\mathit \nu}}_{{\tau}}}$ mass are 1610, 1110, 1100 GeV in the ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit e}}{{\mathit \tau}}$ , and ${{\mathit \mu}}{{\mathit \tau}}$ channels, respectively.
16  AAD 2011H looked in 35 pb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events with one electron and one muon of opposite charge from the production of ${{\widetilde{\mathit \nu}}_{{\tau}}}$ via an RPV ${{\mathit \lambda}^{\,'}}_{311}$ coupling and followed by a decay via ${{\mathit \lambda}}_{312}$ into ${{\mathit e}}{+}$ ${{\mathit \mu}}$ . No evidence for an excess over the SM expectation is observed, and a limit is derived in the plane of ${{\mathit \lambda}^{\,'}}_{311}$ versus ${\mathit m}_{{{\widetilde{\mathit \nu}}}}$ for several values of ${{\mathit \lambda}}_{312}$, see their Fig. 2. Superseded by AAD 2011Z.
17  AALTONEN 2010Z searched in 1 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV for events from the production ${{\mathit d}}$ ${{\overline{\mathit d}}}$ $\rightarrow$ ${{\widetilde{\mathit \nu}}_{{\tau}}}$ with the subsequent decays ${{\widetilde{\mathit \nu}}_{{\tau}}}$ $\rightarrow$ ${{\mathit e}}{{\mathit \mu}}$ , ${{\mathit \mu}}{{\mathit \tau}}$ , ${{\mathit e}}{{\mathit \tau}}$ in the MSSM framework with RPV. Two isolated leptons of different flavor and opposite charges are required, with ${{\mathit \tau}}$s identified by their hadronic decay. No statistically significant excesses are observed over the SM background. Upper limits on ${{\mathit \lambda}_{{311}}^{'2}}$ times the branching ratio are listed in their Table III for various ${{\widetilde{\mathit \nu}}_{{\tau}}}$ masses. Limits on the cross section times branching ratio for ${{\mathit \lambda}_{{311}}^{\,'}}$ = 0.10 and ${{\mathit \lambda}_{{i3k}}}$ = 0.05, displayed in Fig. 2, are used to set limits on the ${{\widetilde{\mathit \nu}}_{{\tau}}}$ mass of 558 GeV for the ${{\mathit e}}{{\mathit \mu}}$ , 441 GeV for the ${{\mathit \mu}}{{\mathit \tau}}$ and 442 GeV for the ${{\mathit e}}{{\mathit \tau}}$ channels.
18  ABAZOV 2010M looked in 5.3 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ collisions at $\sqrt {s }$ = 1.96 TeV for events with exactly one pair of high ${{\mathit p}_{{T}}}$ isolated ${{\mathit e}}{{\mathit \mu}}$ and a veto against hard jets. No evidence for an excess over the SM expectation is observed, and a limit at 95$\%$ C.L. on the cross section times branching ratio is derived, see their Fig. 3. These limits are translated into limits on couplings as a function of ${\mathit m}_{{{\widetilde{\mathit \nu}}_{{\tau}}}}$ as shown on their Fig. 4. As an example, for ${\mathit m}_{{{\widetilde{\mathit \nu}}_{{\tau}}}}$ = 100 GeV and ${{\mathit \lambda}_{{312}}}{}\leq{}$ 0.07, couplings ${{\mathit \lambda}_{{311}}^{\,'}}$ $>$ $7.7 \times 10^{-4}$ are excluded.
19  ABDALLAH 2004H use data from LEP~1 and $\sqrt {s }$ = $192 - 208$~GeV. They re-use results or re-analyze the data from ABDALLAH 2003M to put limits on the parameter space of anomaly-mediated supersymmetry breaking (AMSB), which is scanned in the region 1$<{{\mathit m}}_{3/2}<$50~TeV, 0$<{{\mathit m}_{{0}}}<$1000~GeV, 1.5$<$tan ${{\mathit \beta}}<$35, both signs of ${{\mathit \mu}}$. The constraints are obtained from the searches for mass degenerate chargino and neutralino, for SM-like and invisible Higgs, for leptonically decaying charginos and from the limit on non-SM ${{\mathit Z}}$ width of 3.2~MeV. The limit is for ${\mathit m}_{{{\mathit t}}}$ = 174.3~GeV (see Table 2 for other ${\mathit m}_{{{\mathit t}}}$ values). The limit improves to 114 GeV for ${{\mathit \mu}}$ $<$ 0.
20  ADRIANI 1993M limit from $\Delta \Gamma\mathrm {({{\mathit Z}})}$(invisible)$<16.2$ MeV.
21  ALEXANDER 1991F limit is for one species of ${{\widetilde{\mathit \nu}}}$ and is derived from $\Gamma$(invisible, new)$/\Gamma\mathrm {( {{\mathit \ell}} {{\mathit \ell}} )}$ $<~0.38$.
References:
 SIRUNYAN 2019AO
EPJ C79 305 Search for resonant production of second-generation sleptons with same-sign dimuon events in proton-proton collisions at $\sqrt{s} =$ 13 TeV
 AABOUD 2018CM
PR D98 092008 Search for lepton-flavor violation in different-flavor, high-mass final states in $pp$ collisions at $\sqrt s=13?$?TeV with the ATLAS detector
 AABOUD 2018Z
PR D98 032009 Search for supersymmetry in events with four or more leptons in $\sqrt{s}=13$ TeV $pp$ collisions with ATLAS
 SIRUNYAN 2018AT
JHEP 1804 073 Search for lepton-flavor violating decays of heavy resonances and quantum black holes to e? final states in proton-proton collisions at $\sqrt{s}=13$ TeV
 AABOUD 2016P
EPJ C76 541 Search for New Phenomena in Different-Flavour high-Mass Dilepton Final States in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 13 Tev with the ATLAS Detector
 KHACHATRYAN 2016BE
EPJ C76 317 Search for Lepton Flavour Violating Decays of Heavy Resonances and Quantum Black Holes to an ${{\mathit e}}{{\mathit \mu}}$ Pair in Proton-Proton Collisions at $\sqrt {s }$ = 8 TeV
PRL 115 031801 Search for a Heavy Neutral Particle Decaying to ${{\mathit e}}{{\mathit \mu}}$, ${{\mathit e}}{{\mathit \tau}}$, or ${{\mathit \mu}}{{\mathit \tau}}$ in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV with the ATLAS Detector
PR D90 052001 Search for Supersymmetry in Events with Four or More Leptons in $\sqrt {s }$ = 8 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
PL B723 15 Search for a Heavy Narrow Resonance Decaying to ${{\mathit e}}{{\mathit \mu}}$, ${{\mathit e}}{{\mathit \tau}}$, or ${{\mathit \mu}}{{\mathit \tau}}$ with the ATLAS Detector in $\sqrt {s }$ = 7 TeV ${{\mathit p}}{{\mathit p}}$ Collisions at the LHC
EPJ C71 1809 Search for a Heavy Neutral Particle Decaying into an Electron and a Muon using 1 fb${}^{-1}$ of ATLAS Data
PRL 106 251801 Search for a Heavy Particle Decaying into an Electron and a Muon with the ATLAS Detector in $\sqrt {s }$ = 7 TeV ${{\mathit p}}{{\mathit p}}$ collisions at the LHC.
 AALTONEN 2010Z
PRL 105 191801 Search for $\mathit R$-Parity Violating Decays of Sneutrinos to ${{\mathit e}}{{\mathit \mu}}$, ${{\mathit \mu}}{{\mathit \tau}}$, and ${{\mathit e}}{{\mathit \tau}}$ Pairs in ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 ABAZOV 2010M
PRL 105 191802 Search for Sneutrino Production in ${{\mathit e}}{{\mathit \mu}}$ Final States in 5.3 fb${}^{-1}$ of ${{\mathit p}}{{\overline{\mathit p}}}$ Collisions at $\sqrt {s }$ = 1.96 TeV
 ABDALLAH 2004H
EPJ C34 145 Search for SUSY in the AMSB Scenario with the DELPHI Detector
 ABDALLAH 2003M
EPJ C31 421 Searches for Supersymmetric Particles in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions up to 208 GeV and Interpretation of the Results within the MSSM
 HEISTER 2002N
PL B544 73 Absolute Lower Limits on the Masses of Selectrons and Sneutrinos in the MSSM
PRPL 216 253 Searches for New Particles in ${{\mathit Z}}$ Decays using the ALEPH Detector
NP B367 511 Determination of ${{\mathit Z}^{0}}$ Resonance Parameters and Couplings from its Hadronic and Leptonic Decays
ZPHY C52 175 Measurement of the ${{\mathit Z}^{0}}$ Line Shape Parameters and the Electroweak Couplings of Charged Leptons