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 violating ${{\widetilde{\mathit \tau}}}$ (Stau) mass limit

INSPIRE   JSON  (beta) PDGID:
S046STU
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
$\bf{> 1200}$ 95 1
AAD
2021Y
 ATLS ${}\geq{}4{{\mathit \ell}}$, ${{\mathit \lambda}_{{{12k}}}}{}\not=$ 0, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}}$ = 900 GeV (mass-degenerate ${{\widetilde{\mathit \ell}}_{{{L}}}}$ and ${{\widetilde{\mathit \nu}}}$ of all 3 generations)
$> 870$ 95 1
AAD
2021Y
 ATLS ${}\geq{}4{{\mathit \ell}}$, ${{\mathit \lambda}_{{{i 33}}}}{}\not=$ 0, ${\mathit m}_{{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}}$ = 450 GeV (mass-degenerate ${{\widetilde{\mathit \ell}}_{{{L}}}}$ and ${{\widetilde{\mathit \nu}}}$ of all 3 generations)
$> 1060$ 95 2
AABOUD
2018Z
 ATLS ${}\geq{}4{{\mathit \ell}}$, ${{\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 2
AABOUD
2018Z
 ATLS ${}\geq{}4{{\mathit \ell}}$, ${{\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)
$\bf{> 90}$ 95 3
ABDALLAH
2004M
 DLPH ${{\widetilde{\mathit \tau}}_{{{R}}}}$, indirect, $\Delta \mathit m>$5~GeV
• • We do not use the following data for averages, fits, limits, etc. • •
$> 74$ 95 4
ABBIENDI
2004F
 OPAL ${{\widetilde{\mathit \tau}}_{{{L}}}}$
1  AAD 2021Y searched in 139 ${\mathrm {fb}}{}^{-1}$ of ${{\mathit p}}{{\mathit p}}$ collisions at $\sqrt {s }$ = 13 TeV for supersymmetry in events with four or more leptons (electrons, muons and tau-leptons). No significant excess above the Standard Model expectations is observed. Limits are set on Tchi1n12-GGM, and RPV models similar to Tchi1n2I, Tglu1A (with ${{\mathit q}}$ = ${{\mathit u}}$, ${{\mathit d}}$, ${{\mathit s}}$, ${{\mathit c}}$, ${{\mathit b}}$, with equal branching fractions), and ${{\widetilde{\mathit \ell}}_{{{L}}}}$ $/$ ${{\widetilde{\mathit \nu}}}$ $\rightarrow$ ${{\mathit \ell}}$ $/$ ${{\mathit \nu}}{{\widetilde{\mathit \chi}}_{{{1}}}^{0}}$ (mass-degenerate ${{\widetilde{\mathit \ell}}_{{{L}}}}$ and ${{\widetilde{\mathit \nu}}}$ of all 3 generations), all with ${{\widetilde{\mathit \chi}}_{{{1}}}^{0}}$ $\rightarrow$ ${{\mathit \ell}^{\pm}}{{\mathit \ell}^{\mp}}{{\mathit \nu}}$ via ${{\mathit \lambda}_{{{12k}}}}$ or ${{\mathit \lambda}_{{{i 33}}}}$ (where $\mathit i,k$ $\in$ 1,2), see their Figure 11.
2  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.
3  ABDALLAH 2004M use data from $\sqrt {s }$ = $192 - 208$~GeV to derive limits on sparticle masses under the assumption of RPV with ${{\mathit L}}{{\mathit L}}{{\overline{\mathit E}}}$ couplings. The results are valid for ${{\mathit \mu}}$ = $-200$~GeV, tan ${{\mathit \beta}}$ = 1.5, $\Delta \mathit m$ $>$ 5~GeV and assuming a BR of 1 for the given decay. The limit quoted is for indirect decays using the neutralino constraint of 39.5 GeV, also derived in ABDALLAH 2004M. For indirect decays via ${{\mathit L}}{{\mathit L}}{{\overline{\mathit E}}}$ the limit decreases to 86 GeV if the constraint from the neutralino is not used. Supersedes the result of ABREU 2000U.
4  ABBIENDI 2004F use data from $\sqrt {s }$ = $189 - 209$~GeV. They derive limits on sparticle masses under the assumption of RPV with ${{\mathit L}}{{\mathit L}}{{\overline{\mathit E}}}$ or ${{\mathit L}}{{\mathit Q}}{{\overline{\mathit D}}}$ couplings. The results are valid for tan ${{\mathit \beta}}$ = 1.5, ${{\mathit \mu}}$ = $-200$~GeV, with, in addition, $\Delta \mathit m$ $>$ 5~GeV for indirect decays via ${{\mathit L}}{{\mathit Q}}{{\overline{\mathit D}}}$. The limit quoted applies to direct decays with ${{\mathit L}}{{\mathit L}}{{\overline{\mathit E}}}$ couplings and improves to 75~GeV for ${{\mathit L}}{{\mathit Q}}{{\overline{\mathit D}}}$ couplings. The limit on the ${{\widetilde{\mathit \tau}}_{{{R}}}}$ mass for indirect decays is 92~GeV for ${{\mathit L}}{{\mathit L}}{{\overline{\mathit E}}}$ couplings at ${\mathit m}_{{{\widetilde{\mathit \chi}}^{0}}}$ = 10~GeV and no exclusion is obtained for ${{\mathit L}}{{\mathit Q}}{{\overline{\mathit D}}}$ couplings. Supersedes the results of ABBIENDI 2000.
References