# Charged sleptons

This section contains limits on charged scalar leptons (${{\widetilde{\mathit \ell}}}$, with ${{\mathit \ell}}={{\mathit e}},{{\mathit \mu}},{{\mathit \tau}}$). Studies of width and decays of the ${{\mathit Z}}$ boson (use is made here of $\Delta \Gamma _{{\mathrm {inv}}}<2.0~$MeV, LEP 2000 ) conclusively rule out ${\mathit m}_{{{\widetilde{\mathit \ell}}_{{R}}}}<40~$GeV (41 GeV for ${{\widetilde{\mathit \ell}}_{{L}}}$) , independently of decay modes, for each individual slepton. The limits improve to 43$~$GeV ($43.5$ GeV for ${{\widetilde{\mathit \ell}}_{{L}}}$) assuming all 3 flavors to be degenerate. Limits on higher mass sleptons depend on model assumptions and on the mass splitting $\Delta \mathit m$= ${\mathit m}_{{{\widetilde{\mathit \ell}}}}–{\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$. The mass and composition of ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ may affect the selectron production rate in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions through ${{\mathit t}}$-channel exchange diagrams. Production rates are also affected by the potentially large mixing angle of the lightest mass eigenstate ${{\widetilde{\mathit \ell}}_{{1}}}={{\widetilde{\mathit \ell}}_{{R}}}$ sin$\theta _{{{\mathit \ell}}}$ + ${{\widetilde{\mathit \ell}}_{{L}}}$ cos $\theta _{{{\mathit \ell}}}$. It is generally assumed that only ${{\widetilde{\mathit \tau}}}$ may have significant mixing. The coupling to the ${{\mathit Z}}$ vanishes for $\theta _{{{\mathit \ell}}}$=0.82. In the high-energy limit of ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions the interference between ${{\mathit \gamma}}$ and ${{\mathit Z}}$ exchange leads to a minimal cross section for $\theta _{{{\mathit \ell}}}$=0.91, a value which is sometimes used in the following entries relative to data taken at LEP2. When limits on ${\mathit m}_{{{\widetilde{\mathit \ell}}_{{R}}}}$ are quoted, it is understood that limits on ${\mathit m}_{{{\widetilde{\mathit \ell}}_{{L}}}}$ are usually at least as strong.
Possibly open decays involving gauginos other than ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ will affect the detection efficiencies. Unless otherwise stated, the limits presented here result from the study of ${{\widetilde{\mathit \ell}}^{+}}{{\widetilde{\mathit \ell}}^{-}}$ production, with production rates and decay properties derived from the MSSM. Limits made obsolete by the recent analyses of ${{\mathit e}^{+}}{{\mathit e}^{-}}$ collisions at high energies can be found in previous Editions of this Review.
For decays with final state gravitinos (${{\widetilde{\mathit G}}}$), ${\mathit m}_{{{\widetilde{\mathit G}}}}$ is assumed to be negligible relative to all other masses.

# R-parity conserving ${{\widetilde{\boldsymbol \tau}}}$ (Stau) mass limit INSPIRE search

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
$>85.2$ 1
 2004
OPAL $\Delta \mathit m>$ 6 GeV, $\theta _{\tau }=\pi$/2, $\vert {{\mathit \mu}}\vert >$ 100~GeV, tan $\beta$=1.5
$>78.3$ 2
 2004
L3 $\Delta \mathit m>$ 15 GeV, $\theta _{{{\mathit \tau}}}={{\mathit \pi}}$/2, $\vert {{\mathit \mu}}\vert >$200~GeV,tan $\beta {}\geq{}$2
$\bf{>81.9}$ 95 3
 2003 M
DLPH $\Delta {{\mathit m}}>$15~GeV, all $\theta _{{{\mathit \tau}}}$
$>79$ 95 4
 2002 E
ALEP $\Delta \mathit m>15$ GeV, $\theta _{{{\mathit \tau}}}=\pi$/2
$>76$ 95 4
 2002 E
ALEP $\Delta \mathit m>15$ GeV, $\theta _{{{\mathit \tau}}}=0.91$
• • • We do not use the following data for averages, fits, limits, etc. • • •
95 5
 2017 L
CMS 2 ${{\mathit \tau}}+\not E_T$, ${{\widetilde{\mathit \tau}}_{{L}}}$ $\rightarrow$ ${{\mathit \tau}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
$\text{none 109}$ 95 6
 2016 AA
ATLS 2 hadronic ${{\mathit \tau}}$ + $\not E_T$, ${{\widetilde{\mathit \tau}}_{{R/L}}}$ $\rightarrow$ ${{\mathit \tau}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV
7
 2012 AF
ATLS 2${{\mathit \tau}}$ + jets + $\not E_T$, GMSB
8
 2012 AG
ATLS ${}\geq{}$ 1${{\mathit \tau}_{{h}}}$ + jets + $\not E_T$, GMSB
9
 2012 CM
ATLS ${}\geq{}1{{\mathit \tau}}$ + jets + $\not E_T$, GMSB
$> 87.4$ 95 10
 2006 B
OPAL ${{\widetilde{\mathit \tau}}_{{R}}}$ $\rightarrow$ ${{\mathit \tau}}{{\widetilde{\mathit G}}}$ , all ${{\mathit \tau}}({{\widetilde{\mathit \tau}}_{{R}}}$)
$> 68$ 95 11
 2004 H
DLPH AMSB, ${{\mathit \mu}}$ $>$ 0
$\text{none } {\mathit m}_{{{\mathit \tau}}}\text{-} \text{ 26.3}$ 95 3
 2003 M
DLPH $\Delta {{\mathit m}}>{\mathit m}_{{{\mathit \tau}}}$, all $\theta _{{{\mathit \tau}}}$
1  ABBIENDI 2004 search for ${{\widetilde{\mathit \tau}}}{{\widetilde{\mathit \tau}}}$ production in acoplanar di-tau final states in the $183 - 208$~GeV data. See Fig.$~$15 for the dependence of the limits on ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ and for the limit at tan $\beta$=35. Under the assumption of 100\% branching ratio for ${{\widetilde{\mathit \tau}}_{{R}}}$ $\rightarrow$ ${{\mathit \tau}}$ ~${{\widetilde{\mathit \chi}}_{{1}}^{0}}$, the limit improves to 89.8~GeV for $\Delta \mathit m>$ 8$~$GeV. See Fig.~12 for the dependence of the limits on m$_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ at several values of the branching ratio and for their dependence on $\theta _{\tau }$. This limit supersedes ABBIENDI 2000G.
2  ACHARD 2004 search for ${{\widetilde{\mathit \tau}}}{{\widetilde{\mathit \tau}}}$ production in acoplanar di-tau final states in the $192 - 209$ GeV data. Limits on ${\mathit m}_{{{\widetilde{\mathit \tau}}_{{R}}}}$ are derived from a scan over the MSSM parameter space with universal GUT scale gaugino and scalar masses and , 1 ${}\leq{}$tan $\beta {}\leq{}$60 and $-2{}\leq{}\mu {}\leq{}$ 2 TeV. See Fig.~4 for the dependence of the limits on ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$.
3  ABDALLAH 2003M looked for acoplanar ditaus $\text{+}\not E$ final states at $\sqrt {s }$ = $130 - 208$ GeV. A dedicated search was made for low mass ${{\widetilde{\mathit \tau}}}$s decoupling from the ${{\mathit Z}^{0}}$. The limit assumes B( ${{\widetilde{\mathit \tau}}}$ $\rightarrow$ ${{\mathit \tau}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ ) = 100\%. See Fig.~20 for limits on the (${\mathit m}_{{{\widetilde{\mathit \tau}}}},{\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$) plane and as function of the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ mass and of the branching ratio. The limit in the low-mass region improves to 29.6 and 31.1 GeV for ${{\widetilde{\mathit \tau}}_{{R}}}$ and ${{\widetilde{\mathit \tau}}_{{L}}}$, respectively, at $\Delta \mathit m>$ ${\mathit m}_{{{\mathit \tau}}}$. The limit in the high-mass region improves to 84.7$~$GeV for ${{\widetilde{\mathit \tau}}_{{R}}}$ and $\Delta \mathit m>$ 15$~$GeV. These limits include and update the results of ABREU 2001 .
4  HEISTER 2002E looked for acoplanar ditau + $\not E_T$ final states from ${{\mathit e}^{+}}{{\mathit e}^{-}}$ interactions between 183 and 209 GeV. The mass limit assumes B( ${{\widetilde{\mathit \tau}}}$ $\rightarrow$ ${{\mathit \tau}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ )=1. See their Fig.$~$4 for the dependence of the limit on $\Delta \mathit m$. These limits include and update the results of BARATE 2001 .
5  KHACHATRYAN 2017L searched in about 19 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV for events with two ${{\mathit \tau}}$ (at least one decaying hadronically) and $\not E_T$. Results were interpreted to set constraints on the cross section for production of ${{\widetilde{\mathit \tau}}_{{L}}}$ pairs for ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$=1 GeV. No mass constraints are set, see their Fig. 7.
6  AAD 2016AA summarized and extended ATLAS searches for electroweak supersymmetry in final states containing several charged leptons, $\not E_T$, with or without hadronic jets, in 20 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 8 TeV. The paper reports 95$\%$ C.L. exclusion limits on the cross-section for production of ${{\widetilde{\mathit \tau}}_{{R}}}$ and ${{\widetilde{\mathit \tau}}_{{L}}}$ pairs for various ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$, using the 2 hadronic ${{\mathit \tau}}$ + $\not E_T$ analysis. The ${\mathit m}_{{{\widetilde{\mathit \tau}}_{{R/L}}}}$ = 109 GeV is excluded for ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}}$ = 0 GeV, with the constraints being stronger for ${{\widetilde{\mathit \tau}}_{{R}}}$. See their Fig. 12.
7  AAD 2012AF searched in 2 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events with two tau leptons, jets and large $\not E_T$ in a GMSB framework. No significant excess above the expected background was found and an upper limit on the visible cross section for new phenomena is set. A 95$\%$ C.L. lower limit of 32 TeV on the mGMSB breaking scale ${{\mathit \Lambda}}$ is set for ${{\mathit M}_{{mess}}}$ = 250 TeV, ${{\mathit N}_{{S}}}$ = 3, ${{\mathit \mu}}$ $>$ 0 and ${{\mathit C}_{{grav}}}$ = 1, independent of tan ${{\mathit \beta}}$.
8  AAD 2012AG searched in 2.05 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 7 TeV for events with at least one hadronically decaying tau lepton, jets, and large $\not E_T$ in a GMSB framework. No significant excess above the expected background was found and an upper limit on the visible cross section for new phenomena is set. A 95$\%$ C.L. lower limit of 30 TeV on the mGMSB breaking scale ${{\mathit \Lambda}}$ is set for ${{\mathit M}_{{mess}}}$ = 250 TeV, ${{\mathit N}_{{S}}}$ = 3, ${{\mathit \mu}}$ $>$ 0 and ${{\mathit C}_{{grav}}}$ = 1, independent of tan ${{\mathit \beta}}$. For large values of tan ${{\mathit \beta}}$, the limit on ${{\mathit \Lambda}}$ increases to 43 TeV.
9  AAD 2012CM searched in 4.7 fb${}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$=7 TeV for events with at least one tau lepton, zero or one additional light lepton (${{\mathit e}}/{{\mathit \mu}}$) jets, and large $\not E_T$ in a GMSB framework. No significant excess above the expected background was found and an upper limit on the visible cross section for new phenomena is set. A 95\% C. L. lower limit of 54 TeV on the mGMSB breaking scale ${{\mathit \Lambda}}$ is set for ${{\mathit M}_{{mess}}}$ = 250 TeV, ${{\mathit N}_{{S}}}$ = 3, ${{\mathit \mu}}$ $>$ 0 and ${{\mathit C}_{{grav}}}$ = 1, for tan ${{\mathit \beta}}$ $>$ 20. Here the ${{\widetilde{\mathit \tau}}_{{1}}}$ is the NLSP.
10  ABBIENDI 2006B use 600 pb${}^{-1}$ of data from $\sqrt {s }$ = $189 - 209$ GeV. They look for events from pair-produced staus in a GMSB scenario with ${{\widetilde{\mathit \tau}}}$ NLSP including prompt ${{\widetilde{\mathit \tau}}}$ decays to ditaus + $\not E$ final states, large impact parameters, kinked tracks and heavy stable charged particles. Limits on the cross-section are computed as a function of m(${{\widetilde{\mathit \tau}}}$) and the lifetime, see their Fig. 7. The limit is compared to the $\sigma \cdot{}\mathit BR{}^{2}$ from a scan over the GMSB parameter space.
11  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 75 GeV for ${{\mathit \mu}}$ $<$ 0.
References:
 KHACHATRYAN 2017L
JHEP 1704 018 Search for Electroweak Production of Charginos in Final States with Two ${{\mathit \tau}}$ Leptons in ${{\mathit p}}{{\mathit p}}$ Collisions at $\sqrt {s }$ = 8 TeV
 AAD 2016AA
PR D93 052002 Search for the Electroweak Production of Supersymmetric Particles in $\sqrt {s }$ = 8 TeV ${{\mathit p}}{{\mathit p}}$ Collisions with the ATLAS Detector
 AAD 2012CM
EPJ C72 2215 Search for Supersymmetry in Events with Large Missing Transverse Momentum, Jets, and at Least One tau Lepton in 7 TeV Proton$−$Proton Collision Data with the ATLAS Detector
 AAD 2012AG
PL B714 197 Search for Supersymmetry with Jets, Missing Transverse Momentum and at least One Hadronically Decaying ${{\mathit \tau}}$ Lepton in Proton$−$Proton Collisions at $\sqrt {s }$ = 7 TeV with the ATLAS Detector
 AAD 2012AF
PL B714 180 Search for Events with Large Missing Transverse Momentum, Jets, and at least Two tau Leptons in 7 TeV Proton$−$Proton Collision Data with the ATLAS Detector
 ABBIENDI 2006B
EPJ C46 307 Searches for Gauge-Mediated Supersymmetry Breaking Topologies in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at Centre-of-Mass Energies up to $\sqrt {s }$ = 209 GeV
 ABBIENDI 2004
EPJ C32 453 Search for Anomalous Production of Dilepton Events with Missing Transverse Momentum in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = $183 - 209$ GeV
 ABDALLAH 2004H
EPJ C34 145 Search for SUSY in the AMSB Scenario with the DELPHI Detector
 ACHARD 2004
PL B580 37 Search for Scalar Leptons and Scalar Quarks at LEP
 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 2002E
PL B526 206 Search for Scalar Leptons in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at Center-of-mass Energies upto 209 GeV
 BARATE 2001E
EPJ C19 213 Measurements of B( ${{\mathit b}}$ $\rightarrow$ ${{\mathit \tau}^{-}}{{\overline{\mathit \nu}}_{{\tau}}}{{\mathit X}}$ ) and B( ${{\mathit b}}$ $\rightarrow$ ${{\mathit \tau}^{-}}{{\overline{\mathit \nu}}_{{\tau}}}{{\mathit D}^{*\pm}}{{\mathit X}}$ ) and upper Limits on B( ${{\mathit B}^{-}}$ $\rightarrow$ ${{\mathit \tau}^{-}}{{\overline{\mathit \nu}}_{{\tau}}}$ ) and B( ${{\mathit b}}$ $\rightarrow$ ${{\mathit s}}{{\mathit \nu}}{{\overline{\mathit \nu}}}$ )
 ABBIENDI 2004N
PL B602 167 Multiphoton Events with Large Missing Energy in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = $192 - 209$ GeV
 ABREU 2001K
PL B511 159 Measurement of the Mass and Width of the ${{\mathit W}}$ Boson in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 189 GeV
 ABBIENDI 2000G
EPJ C14 51 Search for Anomalous Production of Acoplanar Dilepton Events in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 183 and 189 GeV
 PDG 2014
CP C38 070001 Review of Particle Physics 2014