Results are presented from searches for the standard model Higgs boson in proton-proton collisions at root s = 7 and 8 TeV in the Compact Muon Solenoid experiment at the LHC, using data samples corresponding to integrated luminosities of up to 5.1 fb(-1) at 7 TeV and 5.3 fb(-1) at 8 TeV. The search is performed in five decay modes: gamma gamma, ZZ, W+W-, tau(+)tau(-), and b (b) over bar. An excess of events is observed above the expected background, with a local significance of 5.0 standard deviations, at a mass near 125 GeV, signalling the production of a new particle. The expected significance for a standard model Higgs boson of that mass is 5.8 standard deviations. The excess is most significant in the two decay modes with the best mass resolution, gamma gamma and ZZ; a fit to these signals gives a mass of 125.3 +/- 0.4(stat.) +/- 0.5(syst.) GeV. The decay to two photons indicates that the new particle is a boson with spin different from one. (C) 2012 CERN. Published by Elsevier B.V. All rights reserved

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.

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The analysis of a combined data set, totaling 3.6 × 10(14) stopped muons on target, in the search for the lepton flavor violating decay μ(+) → e(+)γ is presented. The data collected by the MEG experiment at the Paul Scherrer Institut show no excess of events compared to background expectations and yield a new upper limit on the branching ratio of this decay of 5.7 × 10(-13) (90% confidence level). This represents a four times more stringent limit than the previous world best limit set by MEG.

A sample of 1.69 × 10 7 fully reconstructed π 0 → γ e + e − decay candidates collected by the NA48/2 experiment at CERN in 2003-2004 is analyzed to search for the dark photon (A) production in the π 0 → γ A decay followed by the prompt A → e + e − decay. No signal is observed, and an exclusion region in the plane of the dark photon mass m A and mixing parameter ε 2 is established. The obtained upper limits on ε 2 are more stringent than the previous limits in the mass range 9 MeV/c 2 < m A < 70 MeV/c 2. The NA48/2 sensitivity to the dark photon production in the K ± → π ± A decay is also evaluated. 0. Introduction Kaons are a source of tagged neutral pion decays, and high intensity kaon experiments provide opportunities for precision π 0 decay measurements. The NA48/2 experiment at the CERN SPS collected a large sample of charged kaon (K ±) decays in flight, corresponding to about 2 × 10 11 K ± decays in the fiducial decay volume. This letter reports the search for a hypothetical dark pho-ton (DP, denoted A) using a large sample of tagged π 0 mesons from identified K ± → π ± π 0 and K ± → π 0 μ ± ν decays. In a rather general set of hidden sector models with an extra U (1) gauge symmetry [1], the interaction of the DP with the visible sector proceeds through kinetic mixing with the Standard Model (SM) hypercharge. Such scenarios with GeV-scale dark matter provide possible explanations to the observed rise in the cosmic-ray positron fraction with energy and the muon gyromag-netic ratio (g − 2) measurement [2]. The DP is characterized by two a priori unknown parameters, the mass m A and the mixing parameter ε 2. Its possible production in the π 0 decay and its subsequent decay proceed via the chain π 0 → γ A , A → e + e −. The expected branching fraction of the above π 0 decay is [3] B(π 0 → γ A) = 2ε 2 1 − m 2 A m 2 π 0 3 B(π 0 → γ γ), (1) which is kinematically suppressed as m A approaches m π 0. In the DP mass range 2m e < m A < m π 0 accessible in pion decays, the only allowed tree-level decay into SM fermions is A → e + e − , while the loop-induced SM decays (A → 3γ , A → ν ¯ ν) are highly suppressed. Therefore, for a DP decaying only into SM particles, B(A → e + e −) ≈ 1, and the expected total decay width is [3] A ≈ (A → e + e −) = 1 3 αε 2 m A 1 − 4m 2 e m 2 A 1 + 2m 2 e m 2 A. (2) It follows that, for 2m e m A < m π 0 , the DP mean proper lifetime τ A satisfies the relation cτ A = ¯ hc/ / A ≈ 0.8 μm × 10 −6 ε 2 × 100 MeV/c 2 m A. (3) This analysis is performed assuming that the DP decays at the production point (prompt decay), which is valid for sufficiently large values of m A and ε 2 , as quantified in Section 5. In this case, the DP production and decay signature is identical to that of the Dalitz decay π 0 D → e + e − γ , which therefore represents an irreducible but well controlled background and determines the sensitivity. The NA48/2 experiment provides pure π 0 D decay samples through the reconstruction of K ± → π ± π 0 and K ± → π 0 μ ± ν decays (denoted K 2π and K μ3). Additionally, the K ± → π ±...