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.

Degenerate charged sleptons

INSPIRE   PDGID:
S046DSL
Unless stated otherwise in the comment lines or in the footnotes, the following limits assume 3$~$ families of degenerate charged sleptons.
VALUE (GeV) CL% DOCUMENT ID TECN  COMMENT
$\bf{>93}$ 95 1
BARATE
2001
ALEP $\Delta \mathit m>10$ GeV, ${{\widetilde{\mathit \ell}}_{{R}}^{+}}{{\widetilde{\mathit \ell}}_{{R}}^{-}}$
$\bf{>70}$ 95 1
BARATE
2001
ALEP all $\Delta \mathit m$, ${{\widetilde{\mathit \ell}}_{{R}}^{+}}{{\widetilde{\mathit \ell}}_{{R}}^{-}}$
• • We do not use the following data for averages, fits, limits, etc. • •
$> 91.9$ 95 2
ABBIENDI
2006B
 OPAL ${{\widetilde{\mathit \ell}}_{{R}}}$ $\rightarrow$ ${{\mathit \ell}}{{\widetilde{\mathit G}}}$ , all ${{\mathit \ell}}({{\widetilde{\mathit \ell}}_{{R}}}$)
$>88$ 3
ABDALLAH
2003D
 DLPH ${{\widetilde{\mathit \ell}}_{{R}}}$ $\rightarrow$ ${{\mathit \ell}}{{\widetilde{\mathit G}}}$ , all ${{\mathit \ell}}({{\widetilde{\mathit \ell}}_{{R}}}$)
$>82.7$ 95 4
ACHARD
2002
L3 ${{\widetilde{\mathit \ell}}_{{R}}}$, RPV decays, MSUGRA
$>83$ 95 5
ABBIENDI
2001
OPAL ${{\mathit e}^{+}}$ ${{\mathit e}^{-}}$ $\rightarrow$ ${{\widetilde{\mathit \ell}}_{{1}}}{{\widetilde{\mathit \ell}}_{{1}}}$ , GMSB, tan $\beta $=2
6
ABREU
2001
DLPH ${{\widetilde{\mathit \ell}}}$ $\rightarrow$ ${{\mathit \ell}}{{\widetilde{\mathit \chi}}_{{2}}^{0}}$ , ${{\widetilde{\mathit \chi}}_{{2}}^{0}}$ $\rightarrow$ ${{\mathit \gamma}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ , ${{\mathit \ell}}={{\mathit e}},{{\mathit \mu}}$
$>68.8$ 95 7
ACCIARRI
2001
L3 ${{\widetilde{\mathit \ell}}_{{R}}}$, RPV, $0.7{}\leq{}$tan $\beta {}\leq{}40$
$>84$ 95 8
ABREU
2000V
 DLPH ${{\widetilde{\mathit \ell}}_{{R}}}{{\widetilde{\mathit \ell}}_{{R}}}$ ( ${{\widetilde{\mathit \ell}}_{{R}}}$ $\rightarrow$ ${{\mathit \ell}}{{\widetilde{\mathit G}}}$ ), ${\mathit m}_{{{\widetilde{\mathit G}}}}>$9 eV
1  BARATE 2001 looked for acoplanar dilepton + $\not E_T$ and single electron (for ${{\widetilde{\mathit e}}_{{R}}}{{\widetilde{\mathit e}}_{{L}}}$ ) final states at 189 to 202 GeV. The limit assumes $\mu =-200~$GeV and tan $\beta $=2 for the production cross section and decay branching ratios, evaluated within the MSSM, and zero efficiency for decays other than ${{\widetilde{\mathit \ell}}}$ $\rightarrow$ ${{\mathit \ell}}{{\widetilde{\mathit \chi}}_{{1}}^{0}}$ . The slepton masses are determined from the GUT relations without stau mixing. See their Fig.$~$1 for the dependence of the limit on $\Delta \mathit m$.
2  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 ${{\widetilde{\mathit \ell}}}$ co-NLSP including prompt ${{\widetilde{\mathit \ell}}}$ decays to dileptons + $\not E$ final states, large impact parameters, kinked tracks and heavy stable charged particles. Limits on the cross-section are computed as a function of m(${{\widetilde{\mathit \ell}}}$) 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. The highest mass limit is reached for ${{\widetilde{\mathit \mu}}_{{R}}}$, from which the quoted mass limit is derived by subtracting ${\mathit m}_{{{\mathit \tau}}}$.
3  ABDALLAH 2003D use data from $\sqrt {s }$ = $130 - 208$ GeV to search for tracks with large impact parameter or visible decay vertices and for heavy charged stable particles. Limits are obtained as function of m(${{\widetilde{\mathit G}}}$), after combining these results with the search for slepton pair production in the SUGRA framework from ABDALLAH 2003M to cover prompt decays The above limit is reached for prompt decays and assumes the degeneracy of the sleptons. For limits at different m(${{\widetilde{\mathit G}}}$), see their Fig.$~$9. Supersedes the results of ABREU 2001G.
4  ACHARD 2002 searches for the production of sparticles in the case of RPV prompt decays with $\mathit LL\bar E$ or $\bar U \bar D \bar D$ couplings at $\sqrt {\mathit s }=189 - 208$ GeV. The search is performed for direct and indirect decays, assuming one coupling at the time to be nonzero. The MSUGRA limit results from a scan over the MSSM parameter space with the assumption of gaugino and scalar mass unification at the GUT scale and no mixing in the slepton sector, imposing simultaneously the exclusions from neutralino, chargino, sleptons, and squarks analyses. The limit holds for $\mathit LL\bar E$ couplings and increases to $88.7$ GeV for $\bar U \bar D \bar D$ couplings. For L3 limits from $\mathit LQ\bar D$ couplings, see ACCIARRI 2001 .
5  ABBIENDI 2001 looked for final states with ${{\mathit \gamma}}{{\mathit \gamma}}$ $\not E$, ${{\mathit \ell}}{{\mathit \ell}}$ $\not E$, with possibly additional activity and four leptons + $\not E$ to search for prompt decays of ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ or ${{\widetilde{\mathit \ell}}_{{1}}}$ in GMSB. They derive limits in the plane (${\mathit m}_{{{\widetilde{\mathit \chi}}_{{1}}^{0}}},{\mathit m}_{{{\widetilde{\mathit \tau}}_{{1}}}}$), see Fig.$~$6, allowing either the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ or a ${{\widetilde{\mathit \ell}}_{{1}}}$ to be the NLSP. Two scenarios are considered: tan $\beta $=2 with the 3 sleptons degenerate in mass and tan $\beta $=20 where the ${{\widetilde{\mathit \tau}}_{{1}}}$ is lighter than the other sleptons. Data taken at $\sqrt {\mathit s }=189~$GeV. For tan $\beta $=20, the obtained limits are ${\mathit m}_{{{\widetilde{\mathit \tau}}_{{1}}}}>69~$GeV and $\mathit m_{{{\widetilde{\mathit e}}_{{1}}},{{\widetilde{\mathit \mu}}_{{1}}}}>88~$GeV.
6  ABREU 2001 looked for acoplanar dilepton + diphoton + $\not E$ final states from ${{\widetilde{\mathit \ell}}}$ cascade decays at $\sqrt {\mathit s }=130 - 189$ GeV. See Fig.$~$9 for limits on the ($\mu ,\mathit M_{2}$) plane for ${\mathit m}_{{{\widetilde{\mathit \ell}}}}=80~$GeV, tan $\beta $=1.0, and assuming degeneracy of ${{\widetilde{\mathit \mu}}}$ and ${{\widetilde{\mathit e}}}$.
7  ACCIARRI 2001 searches for multi-lepton and/or multi-jet final states from RPV prompt decays with $\mathit LL\bar E$, $\mathit LQ\bar D$, or $\bar U \bar D \bar D$ couplings at $\sqrt {\mathit s }=189~$GeV. The search is performed for direct and indirect decays of neutralinos, charginos, and scalar leptons, with the ${{\widetilde{\mathit \chi}}_{{1}}^{0}}$ or a ${{\widetilde{\mathit \ell}}}$ as LSP and assuming one coupling to be nonzero at a time. Mass limits are derived using simultaneously the constraints from the neutralino, chargino, and slepton analyses; and the ${{\mathit Z}^{0}}~$width measurements from ACCIARRI 2000C in a scan of the parameter space assuming MSUGRA with gaugino and scalar mass universality. Updates and supersedes the results from ACCIARRI 1999I.
8  ABREU 2000V use data from $\sqrt {\mathit s }$= $130 - 189$ GeV to search for tracks with large impact parameter or visible decay vertices. Limits are obtained as function of ${\mathit m}_{{{\widetilde{\mathit G}}}}$, after combining these results with the search for slepton pair production in the SUGRA framework from ABREU 2001 to cover prompt decays and on stable particle searches from ABREU 2000Q. For limits at different ${\mathit m}_{{{\widetilde{\mathit G}}}}$, see their Fig.$~$12. The above limit assumes the degeneracy of stau and smuon.
References:
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
ABDALLAH 2003D
EPJ C27 153 Search for Supersymmetric Particles in Light Gravitino Scenarios and Sleptons NLSP
ACHARD 2002
PL B524 65 Search for $\mathit R$ Parity Violating Decays of Supersymmetric Particles in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at LEP
ABBIENDI 2001
PL B501 12 Searches for Prompt Light Gravitino Signatures in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 189 GeV
ABREU 2001
EPJ C19 29 Search for Sleptons in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 183 to 189 GeV
ACCIARRI 2001
EPJ C19 397 Search for $\mathit R$-Parity Violating Decays of Supersymmetric Particles in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ = 189 GeV
BARATE 2001
PL B499 67 Search for Supersymmetric Particles in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ Collisions at $\sqrt {s }$ up to 202 GeV and Mass Limit for the Lightest Neutralino
ABREU 2000V
EPJ C16 211 Search for Supersymmetric Particles in Scenarios with a Gravitino LSP and stau NLSP