Causal standard model

Field equations in the minimal Standard Model are equivalent to hyperbolic partial differential equations supplemented by constraints. It is shown that wave fronts of the solutions propagate causally. This statement is valid also for the effective chiral Lagrangian model in which electroweak interactions are treated without the Higgs potential.     

Monojets in the standard model

In a previous analysis it was shown that in the standard model the number of events with large missing transverse energy in pp̄ collision can be experimentally important. Now this analysis is refined to confront the sample of monojet events recently reported by the UA1 collaboration. It is shown how an absolutely normalized calculation based on simple parton level cross sections — which gives good agreement with the production cross sections for observed W and Z events — appears to satisfactory describe the monojet sample. The various sources of uncertainty in the calculation are emphasized.     

Non-commutative standard model: model building

A non-commutative version of the usual electro-weak theory is constructed. We discuss how to overcome the two major problems: (1) although we can have non-commutative U(n) (which we denote by _U* (n)) gauge theory we cannot have non-commutative SU(n) and (2) the charges in non-commutative QED are quantized to just . We show how the latter problem with charge quantization, as well as with the gauge group, can be resolved by taking the gauge group and reducing the extra U(1) factors in an appropriate way. Then we proceed with building the non-commutative version of the standard model by specifying the proper representations for the entire particle content of the theory, the gauge bosons, the fermions and Higgs. We also present the full action for the non-commutative standard model (NCSM). In addition, among several peculiar features of our model, we address the inherent CP violation and new neutrino interactions. Received: 23 January 2003, Published online: 18 June 2003     

Cosmology versus standard model

I will discuss a proposal for a unified solution of the problems of neutrino masses, dark matter, baryon asymmetry of the Universe and inflation, which does not require introduction of any new energy scale besides already known, namely the electroweak and the Planck scales. This point of view, supplemented by a requirement of simplicity, has a number of experimental predictions which can be tested, at least partially, with the use of existing accelerators and the LHC, with current and future X-ray telescopes, and with the Planck mission.     

No-scale supersymmetric standard model

We propose a class of supergravity models coupled to matter in which the scales of supersymmetry breaking and of weak gauge symmetry breaking are both fixed by dimensional transmutation, not put in by hand. The models have a flat potential with zero cosmological constant before the evaluation of weak radiative corrections which determine $\text{m}\text{3}\text{2}\text{, m}{}_{\mathrm{<mtext>W</mtext>}}\text{=}\text{exp}\text{[}\text{?O(1)}\text{α}{}_{\mathrm{<mtext>t</mtext>}}\text{]m}{}_{\mathrm{<mtext>p</mtext>}}\text{:α}{}_{\mathrm{<mtext>t</mtext>}}\text{= O(α)}$. These models are consistent with all particle physi cs and cosmological constraints for top quark masses in the range 30 GeV < m_t < 100 GeV.     

LEP Higgs boson searches beyond the standard model and minimum supersymmetric standard model

Ever since the center-of-mass energy was increased in 1995 above the Zℴ resonance, the four LEP experiments (ALEPH, DELPHI, OPAL and L3) have renewed their effort to search for the Higgs boson. Data taking ended in the year 2000 with about 130 pb⁻¹ of data collected per experiment above 206 GeV ine ⁺ e ⁻¹ collisions but the data analysis is still very active. Most recently, the wealth of theoretical models and predictions has stimulated new analyses and model interpretations which go beyond the standard model and minimal supersymmetric standard model. These include the searches for charged Higgs bosons, models with two Higgs field doublets, searches for ‘fermiophobic’ Higgs decay, invisible Higgs boson decays, decay-mode independent searches, and limits on Yukawa and anomalous Higgs couplings. I review the searches done by the four LEP experiments and present the LEP combined results when they exist.     

The neutrino ball in the standard model

The model of the quasars as a neutrino ball based on the standard model is presented. A realistic quasar with the typical massM=8.42 10⁹ M , the radius of the neutrino ballR=1.66 a.u., and the neutrino numberN=1.07 10⁷² is obtained when the electroweak phase transition is first-order.     

Constrained next-to-minimal supersymmetric standard model

We consider the fully constrained version of the next-to-minimal supersymmetric extension of the standard model (cNMSSM) in which a singlet Higgs superfield is added to the two doublets that are present in the minimal extension (MSSM). Assuming universal boundary conditions at a high scale for the soft supersymmetry-breaking mass parameters as well as for the trilinear interactions, we find that the model is more constrained than the celebrated minimal supergravity model. The phenomenologically viable region in the parameter space of the cNMSSM corresponds to a small value for the universal scalar mass m_{0}: in this case, one single input parameter is sufficient to describe the model's phenomenology once constraints from collider data and cosmology are imposed.