Discovering Supersymmetry at the Tevatron in Wino LSP Scenarios

Abstract

In supersymmetric models, Winos, partners of the SU(2) gauge bosons, may be the lightest supersymmetric particles (LSPs). For generic parameters, charged and neutral Winos are highly degenerate. Charged Winos travel macroscopic distances, but can decay to neutral Winos and extremely soft leptons or pions before reaching the muon chambers, thereby circumventing conventional trigger requirements based on energetic decay products or muon chamber hits. However, these charginos are detectable, and can be triggered on when produced in association with jets. In addition, we propose a new trigger for events with a high p_T track and low hadronic activity. For Tevatron Run II with luminosity 2 fb^-1, the proposed searches can discover Winos with masses up to 300 GeV and explore a substantial portion of the parameter space in sequestered sector models.

Figures (3)

• Figure 1: The mass splitting $\Delta M \equiv m_{\tilde{\chi}^{\pm}_1} - m_{\tilde{\chi}^0_1}$ and decay lengths $c\tau$ in the $(\mu, M_2)$ plane. (a) The anomaly-mediated relation $M_1 \approx 3.3 M_2$ is assumed, and $\tan\beta = 10$. Similar results are obtained for $\mu >0$. The discovery region for trigger II is shown. (See text.) (b) The same for a more general Wino LSP model, with $\tan\beta=3$ and $M_1=-1.5 M_2$, along with the discovery reach for triggers I -- III. (See text.)
• Figure 2: Cross sections (solid) at $\sqrt{s} = 2 \text{ TeV}$ for Wino pair production with at least one charged track traveling a radial length $L$ with $|\eta| < 1.2$. The dependence on decay length $c\tau$ is shown. For the dashed contours, the charged track is also required to have $\beta\gamma < 0.85$. See associated discussion of triggers I, III.
• Figure 3: Cross sections at $\sqrt{s} = 2 \text{ TeV}$ for associated production of a Wino pair and a jet with $p_T > 30 \text{ GeV}$ and $|\eta| < 1.2$. At least one charged Wino is required to travel a radial length $L$ with $|\eta| < 2$. The dependence on decay length $c\tau$ is shown. See associated discussion of trigger II.