The observation of the standard model (SM) Higgs boson decay to a pair of bottom quarks is presented. The main contribution to this result is from processes in which Higgs bosons are produced in association with a W or Z boson (VH), and are searched for in final states including 0, 1, or 2 charged leptons and two identified bottom quark jets. The results from the measurement of these processes in a data sample recorded by the CMS experiment in 2017, comprising 41.3 fb −1 of proton-proton collisions at √ s = 13 TeV, are described. When combined with previous VH measurements using data collected at √ s = 7, 8, and 13 TeV, an excess of events is observed at m H = 125 GeV with a significance of 4.8 standard deviations, where the expectation for the SM Higgs boson is 4.9. The corresponding measured signal strength is 1.01 ± 0.22. The combination of this result with searches by the CMS experiment for H → bb in other production processes yields an observed (expected) significance of 5.6 (5.5) standard deviations and a signal strength of 1.04 ± 0.20.

High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e + e − linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.

We provide a detailed description of the Fortran code CPsuperH, a newly-developed computational package that calculates the mass spectrum and decay widths of the neutral and charged Higgs bosons in the Minimal Supersymmetric Standard Model with explicit CP violation. The program is based on recent renormalization-group-improved diagrammatic calculations that include dominant higher-order logarithmic and threshold corrections, bquark Yukawa-coupling resummation effects and Higgs-boson pole-mass shifts. The code CPsuperH is self-contained (with all subroutines included), is easy and fast to run, and is organized to allow further theoretical developments to be easily implemented * . The fact that the masses and couplings of the charged and neutral Higgs bosons are computed at a similar high-precision level makes it an attractive tool for Tevatron, LHC and LC studies, also in the CP-conserving case. * The program may be obtained from

We compute one-loop corrections to the mass matrix of the neutral Higgs bosons of the Minimal Supersymmetric Standard Model with explicit CP violation. We use the effective potential method, allowing for arbitrary splitting between squark masses. We include terms O(g 2 h 2 ), where g and h stand for electroweak gauge and Yukawa couplings, respectively. Leading two-loop corrections are taken into account by means of appropriately defined running quark masses. 1) IntroductionSupersymmetry is the currently best motivated extension of the Standard Model (SM) of particle physics, since it allows to stabilize the gauge hierarchy without getting into conflict with electroweak precision data. Among all possible supersymmetric theories, the Minimal Supersymmetric Standard Model (MSSM) occupies a special position. It is not only the simplest, i.e. most economical, potentially realistic supersymmetric field theory, it also has just the right particle content to allow for the unification of all gauge interactions [1]. Within the MSSM, the Higgs sector can be singled out: among all the as yet undetected new particles in the MSSM spectrum, the lightest neutral Higgs boson h 1 is the only one for which a strict upper bound on the mass can be given [2], m h 1 < ∼ 130 GeV. A good understanding of the Higgs sector is therefore of crucial importance for experimental tests of the MSSM.It has recently been realized [3] that explicit CP violation in the mass matrices of third generation squarks can induce sizable CP violation in the MSSM Higgs sector through loop corrections. Note that CP violating phases for third generation sfermions can be quite large, since they contribute to the electric dipole moments of the electron and neutron only at the two-loop level [4]. Although a one-loop effect, the induced CP violation in the MSSM Higgs sector can be large enough to significantly affect Higgs phenomenology at present [3, 5] and future [3,6] colliders. An accurate treatment of CP violating loop corrections to the MSSM Higgs sector is therefore of some importance.The first calculations [3] used diagrammatic methods, and diagonalized the resulting mass matrix only approximately. More recently, the effective potential has been used [5, 7] to compute the 3 × 3 mass matrix of the neutral Higgs bosons of the MSSM. However, the results of ref.[5] are not valid for large mass splitting between squark mass eigenstates, while ref. [7] does not include contributions from the bottom-sbottom sector, which can be important for large ratio of vacuum expectation values tanβ. Here we present a calculation based on the full one-loop effective potential, valid for all values of the relevant soft breaking parameters. This extends older results [8] where CP was assumed to be conserved. Moreover, unlike refs.[5,7,8] we include terms O(g 2 h 2 ), where g and h are a weak gauge and third generation Yukawa coupling, respectively. These new terms do not change the spectrum very much, but alter CP violating mixing angles by typically 20%. Finally, we absorb lead...

Gluinos and neutralinos, supersymmetric partners of gluons and neutral electroweak gauge and Higgs bosons, are Majorana particles in the minimal supersymmetric standard model (MSSM). Decays of such self-conjugate particles generate charge symmetric ensembles of final states. Moreover, production channels of supersymmetric particles at colliders are characteristically affected by the Majorana nature of particles exchanged in the production processes. The sensitivity to the Majorana character of the particles can be quantified by comparing the predictions with Dirac exchange mechanisms. A consistent framework for introducing gluino and neutralino Dirac fields can be designed by extending the N ¼ 1 supersymmetry of the MSSM to N ¼ 2 in the gauge sector. We examine to which extent like-sign dilepton production in the processes qq !qq and e À e À !ẽ ÀẽÀ is affected by the exchange of either Majorana or Dirac gluinos and neutralinos, respectively, at the Large Hadron Collider (LHC) and in the prospective e À e À mode of a lepton linear collider.

By studying the threshold dependence of the excitation curve and the angular distribution in Higgs-strahlung at e + e − colliders, e + e − → ZH, the spin of the Higgs boson in the Standard Model and related extensions can be determined unambiguously in a model-independent way.

For large masses, the two heavy neutral Higgs bosons are nearly degenerate in many 2-Higgs doublet models, and particularly in supersymmetric models. In such a scenario the mixing between the states can be very large if the theory is CPnoninvariant. We analyze the formalism describing this configuration, and we point to some interesting experimental consequences.

A comprehensive review of physics at an linear collider in the energy range of  GeV–3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.