I review a heterotic–string solution in which the observable sector effective field theory just below the string scale reduces to that of the MSSM, with the standard observable gauge group being just SU(3)C ×SU(2)L×U(1)Y and the SU(3)C ×SU(2)L×U(1)Y – charged spectrum of the observable sector consisting solely of the MSSM spectrum. Associated with this model is a set of distinct flat directions...

Within the context of the E8 ×E8 heterotic superstring compactified on a smooth CalabiYau threefold with an SU(4) gauge instanton, we show the existence of simple, realistic N = 1 supersymmetric vacua that are compatible with low energy particle physics. The observable sector of these vacua has gauge group SU(3)C ×SU(2)L ×U(1)Y ×U(1)B−L, three families of quarks and leptons, each with an additi...

The Standard Model is based on the gauge invariance principle with gauge group U(1) × SU(2) × SU(3) and suitable representations for fermions and bosons, which are begging for a conceptual understanding. We propose a purely gravitational explanation: space-time has a fine structure given as a product of a four dimensional continuum by a finite noncommutative geometry F. The raison d’être for F ...

R-parity stands as an ad hoc assumption in the most popular version of the supersymmetric standard model. More than fifteen years’ studies of R-parity violations have been restricted to various limiting scenarios. We illustrate how the single-VEV parametrization provides a workable framework to analyze the phenomenology of the complete theory of supersymmetry without R-parity. In our comprehens...

Phenomenological implications of the volume of the Calabi-Yau threefolds on the hidden and observable M-theory boundaries, together with slope stability of their corresponding vector bundles, constrain the set of Kähler moduli which give rise to realistic compactifications of the strongly coupled heterotic string. When vector bundles are constructed using extensions, we provide simple rules to ...

These lectures constitute a short course in ‘Beyond the Standard Model’ for students of experimental particle physics. I discuss the general ideas which guide the construction of models of physics beyond the Standard Model. The central principle, the one which most directly motivates the search for new physics, is the search for the mechanism of the spontaneous symmetry breaking observed in the...

In this conference report a summary is given on the theoretical work that has contributed to provide accurate theoretical predictions for testing the standard model in present and future experiments. Precision calculations for the vector boson masses, for the Z resonance, W pair production, and for the g − 2 of the muon are reviewed and the theoretical situation for the Higgs sector is summariz...

In the minimal supersymmetric standard model, the Higgs sector has two unknown parameters, usually taken to be tanβ ≡ v2/v1 and mA, the mass of its one physical pseudoscalar particle. By minimizing the minimum of the Higgs potential along a certain direction in parameter space, it is shown that mA = MZ + radiative correction, and if one further plausible assumption is made, tanβ > √ 3. If there...

We present a primer on the Standard Model of the electroweak interaction. Emphasis is given to the historical aspects of the theory’s formulation. The radiative corrections to the Standard Model are presented and its predictions for the electroweak parameters are compared with the precise experimental data obtained at the Z pole. Finally, we make some remarks on the perspectives for the discove...

The quantity RK = Γ(K → eν)/Γ(K → μν) studied by the experiment NA62 at CERN is known to probe lepton-flavour violating (LFV) parameters of the Minimal Supersymmetric Standard Model (MSSM). A non-zero parameter δ RR can open the decay channel K → eντ and enhance RK over its Standard-Model value. In the region of the parameter space probed by NA62 the contribution from a bino-stau loop diagram i...