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 ${{\widetilde{\boldsymbol \tau}}}$ (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
• • • We do not use the following data for averages, fits, limits, etc. • • •
$> 74$ 95 1
ABBIENDI
2004F
OPAL RPV, ${{\widetilde{\mathit \tau}}_{{L}}}$
$> 90$ 95 2
ABDALLAH
2004M
DLPH RPV, ${{\widetilde{\mathit \tau}}_{{R}}}$, indirect, $\Delta \mathit m>$5~GeV
1  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 .
2  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.
  References:
ABBIENDI 2004F
EPJ C33 149 Search for $\mathit R$-Parity Violating Decays of Scalar Fermions at LEP
ABDALLAH 2004M
EPJ C36 1 Search for Supersymmetric Particles Assuming $\mathit R$-Parity non-conservation in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 192 to 208 GeV
ABREU 2000U
PL B487 36 Search for SUSY with $\mathit R$-Parity Violating LL${{\overline{\mathit E}}}$ Couplings at $\sqrt {s }$ = 189 GeV
ABBIENDI 2000H
EPJ C14 187 Search for Chargino and Neutralino Production at $\sqrt {s }$ = 189 GeV at LEP
PDG 2014
CP C38 070001 Review of Particle Physics 2014