arXiv subjects
Publications and source records attributed to Yu. F. Pirogov.
The concept of the space-time as emerging in the world phase transition, vs. a priori existing, is put forward. The theory of gravity with two basic symmetries, the global affine one and the general covariance, is developed. Implications for the Universe are indicated.
The concept of the space-time as emerging in the world phase transition, vs. a priori exiting, is put forward. The theory of gravity with two basic symmetries, the global affine one and the general covariance, is developed. Implications for the Universe are indicated.
The metric space-time is revised as a priori existing. It is substituted by the world continuum endowed only with the affine connection. The metric, accompanied by the tensor Goldstone boson, is to emerge during the spontaneous breaking of the global affine symmetry. Implications for gravity and the Universe are indicated.
A modified criterion of the SM perturbative consistency is proposed. It is based on the analytic properties of the two-loop SM running couplings. Under the criterion adopted, the Higgs mass up to 380 GeV might not give rise to the strong coupling prior to the Planck scale. This means that the light Higgs boson is possibly preferred for reasons other than the SM peturbative consistency, i.e. for reasons beyond the SM.
The advantages to consider the ordinary space-time as the symplectic rather than pseudo-orthogonal one are indicated, and the consequences of extending this view to extra space/time dimensions are discussed.
It is conjectured that the symplectic structure of space-time is superior to the metric one. Instead of the commonly adopted pseudo-orthogonal groups SO(1,d-1), d\ge4, the complex symplectic ones Sp(2l,C), l\ge1 are proposed as the local structure groups of the extended space-time. A discrete series of the metric space-times of the particular dimensionalities d=4l^2 and signatures, with l(2l-1) time and l(2l+1) spatial directions, defined over the set of the Hermitian second-rank spin-tensors is proposed as an alternative to the pseudo-Euclidean space-times with extra dimensions. The one-dimensional time-like direction remaining invariant under fixed boosts makes it possible the non-relativistic causality description despite the presence of extra times.
It is conjectured that in the origin of space-time there lies a symplectic rather than metric structure. The complex symplectic symmetry Sp(2l,C), l\ge1 instead of the pseudo-orthogonal one SO(1,d-1), d\ge4 is proposed as the space-time local structure group. A discrete sequence of the metric space-times of the fixed dimensionalities d=(2l)^2 and signatures, with l(2l-1) time-like and l(2l+1) space-like directions, defined over the set of the Hermitian second-rank spin-tensors is considered as an alternative to the pseudo-Euclidean extra dimensional space-times. The basic concepts of the symplectic framework are developed in general, and the ordinary and next-to-ordinary space-time cases with l=1,2, respectively, are elaborated in more detail. In particular, the scheme provides the rationale for the four-dimensionality and 1+3 signature of the ordinary space-time.
Neutrino mixing in the standard model extensions, both renormalizable and effective, with arbitrary numbers of the singlet and left-handed doublet neutrinos is investigated in a systematic fashion. The charged and neutral (the Z and Higgs mediated)lepton currents are written under general Majorana condition, and the odservable independence of the choice of the condition, the rephasing invariance, is studied. A parametrization of the neutrino mixing matrices in the doublet-singlet factorized form is developed. Its relationship with the see-saw mechanism is shown in the limit of a small doublet-singlet mixing. The structure of the mixing matrices relevant to the neutrino oscillation experiments is explicated.
The content of physical massess, mixing angles and CP-violating phases in the lepton sector of extended standard model, both renormalizable and non-renormalizable, with arbitrary numbers of the singlet and left-handed doublet neutrinos is systematically analyzed in the weak basis.
The extension of the standard model with pairs of the vector-like families is studied. The quark mixing matrices for the left- and right-handed charged currents, as well as those for the flavour changing neutral currents, the Z and Higgs mediated, are found. Both the model independent parametrization for an arbitrary case and an explicit realization for the case with one pair of the heavy vector-like families are presented. The extension opens new prospects for studying deviations from the standard model in the future experiments at high energies.
The standard model extended with the pairs of the vector-like families is studied. The model independent analysis for an arbitrary case and an explicit realization for the case with one pair of the heavy vector-like families are considered. The mixing matrices of the light quarks for the left- and right-handed charged currents, as well as those for the flavour changing neutral currents, both the Z and Higgs mediated, are found.
The two-loop renormalization group global profile of the Standard Model (SM) in its full parameter space is investigated. Restrictions on the Higgs boson mass as a function of a cutoff scale are obtained from the stability of the electroweak vacuum and from the perturbative validity both in the Higgs and Yukawa sectors. The cutoff equal to the Planck scale requires the Higgs mass to be M=(161.3+-20.6)+4-10 GeV and M>=140.7+-10 GeV, where the M corridor is the theoretical one and the errors are due to the top mass uncertainty. Modification of the two-loop global profile of the SM extended by one new chiral generation is studied, and bounds on the masses of the generation are derived. Under the precision experiment restriction M<=200 GeV, the forth chiral generation, taken alone, is excluded. Nevertheless a pair of the chiral generations constituing the vector-like one could exist.
In the context of the future high energy - high luminosity electron and muon colliders, all the relevant four-lepton processes with the lepton family violation (LFV) are systematically classified. The most general LFV effective lagrangians are found, and the helicity differential cross sections for the LFV processes are calculated. The six- and eight-lepton Standard Model (SM) backgrounds are discussed, and the LFV processes clean of the six-lepton background are picked out. The possibility to suppress the six-lepton SM background, when present, by the unnatural initial beam polarizations is investigated. It is shown that the four-lepton LFV processes are amenable to experimental study in the lepton-lepton collisions in the most favourable cases up to the underlying scale of order 100 TeV. Studying these processes should provide an essential part of the physics program for the next generation lepton colliders to unravel the outstanding flavour/family problem.