Recent results of the searches for Supersymmetry in final states with one or two leptons at CMS are presented. Many Supersymmetry scenarios, including the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM), predict a substantial amount of events containing leptons, while the largest fraction of Standard Model background events -which are QCD interactions -gets strongly reduced by requiring isolated leptons. The analyzed data was taken in 2011 and corresponds to an integrated luminosity of approximately L = 1 fb −1 . The center-of-mass energy of the pp collisions was √ s = 7 TeV.

We observe a signal for the doubly charmed baryon Xi(+)(cc) in the charged decay mode Xi(+)(cc)-->Lambda(+)(c)K-pi(+) in data from SELEX, the charm hadroproduction experiment at Fermilab. We observe an excess of 15.9 events over an expected background of 6.1+/-0.5 events, a statistical significance of 6.3sigma. The observed mass of this state is 3519+/-1 MeV/c(2). The Gaussian mass width of this state is 3 MeV/c(2), consistent with resolution; its lifetime is less than 33 fs at 90% confidence.

We observe a signal for the doubly charmed baryon Ξ + cc in the decay mode Ξ + cc → pD + K − to complement the previous reported decay Ξ + cc → Λ + c K − π + in data from SELEX, the charm hadroproduction experiment at Fermilab. In this new decay mode we observe an excess of 5.62 events over a combinatoric background estimated by event mixing to be 1.38 ± 0.13 events. The mixed background has Gaussian statistics, giving a signal significance of 4.8σ. The Poisson probability that a background fluctuation can produce the apparent signal is less than 6.4 × 10 −4. The observed mass of this state is 3518 ± 3 MeV/c 2 , consistent with the published result. Averaging the two results gives a mass of 3518.7 ± 1.7 MeV/c 2. The observation of this new weak decay mode confirms the previous SELEX suggestion that this state is a double charm baryon. The relative branching ratio for these two modes is 0.36 ± 0.21.

The Σ − mean squared charge radius has been measured in the space-like Q 2 range 0.035-0.105 GeV 2 /c 2 by elastic scattering of a Σ − beam off atomic electrons. The measurement was performed with the SELEX (E781) spectrometer using the Fermilab hyperon beam at a mean energy of 610 GeV/c. We obtain r 2 ch Σ − = (0.61 ± 0.12 (stat.) ± 0.09 (syst.)) fm 2 . The proton and π − charge radii were measured as well and are consistent with results of other experiments. Our result agrees with the recently measured strong interaction radius of the Σ − .

In this article, construction, operation, and performance of the RICH detector of Fermilab experiment 781 (SELEX) are described. The detector utilizes a matrix of 2848 phototubes for the photocathode to detect Cherenkov photons generated in a 10 m Neon radiator. For the central region an N 0 of 104 cm −1 , corresponding to 13.6 hits on a β = 1 ring, was obtained. The ring radius resolution measured is 1.6 %.