arXiv subjects

P. Tinyakov

Publications and source records attributed to P. Tinyakov.

25 records · Page 2Linked to original sources

arXiv2003

Suppression of baryon number violation in electroweak collisions: Numerical results

We present a semiclassical study of the suppression of topology changing, baryon number violating transitions induced by particle collisions in the electroweak theory. We find that below the sphaleron energy the suppression exponent is remarkably close to the analytic estimates based on a low energy expansion about the instanton. Above the sphaleron energy, the relevant semiclassical solutions have qualitatively different properties from those below the sphaleron: they correspond to jumps on top of the barrier. Yet these processes remain exponentially suppressed, and, furthermore, the tunneling exponent flattens out in energy. We also derive lower bounds on the tunneling exponent which show that baryon number violation remains exponentially suppressed up to very high energies of at least 30 sphaleron masses (250 TeV).

hep-ph↗

arXiv2003

Correlations and Charge Composition of UHECR without Knowledge of Galactic Magnetic Field

We develop a formalism which allows to study correlations of charged UHECR with potential sources without using any Galactic Magnetic Field (GMF) model. The method is free of subjective chose of parameters on which the significance of correlations depends strongly. We show that correlations of the AGASA dataset with BL Lacs (found previously after reconstruction of particle trajectories in a specific GMF) are present intrinsically and can be detected without reference to a particular model of magnetic field.

astro-ph↗

arXiv2002

Sources of sub-GZK cosmic rays

We analyze the existing evidence that BL Lacertae objects (BL Lacs) are sources of the highest-energy cosmic rays. We argue that three independent signatures observed in the real data -- (1) improvement of correlations with corrections of trajectories for the Galactic magnetic field; (2) connection between gamma-ray and UHECR emissions; (3) non-uniform distribution of correlating rays over the sky -- are consistent with the hypothesis that a substantial fraction of cosmic rays in the energy range 40-60 EeV are protons accelerated in BL Lacs.

hep-ph↗

arXiv2002

Evidence for a connection between the gamma-ray and the highest energy cosmic-ray emissions by BL Lacertae objects

A set of potentially gamma-ray--loud BL Lac objects is selected by intersecting the EGRET and BL Lac catalogs. Of the resulting 14 objects, eight are found to correlate with arrival directions of ultra--high-energy cosmic rays (UHECRs), with significance of the order of 5 sigma. This suggests that gamma-ray emission can be used as a distinctive feature of those BL Lac objects that are capable of producing UHECR.

astro-ph↗

arXiv2001

Instanton-Like Processes in Particle Collisions: a Numerical Study of the SU(2)-Higgs Theory below the Sphaleron Energy

We use semiclassical methods to calculate the probability of inducing a change of topology via a high-energy collision in the SU(2)-Higgs theory. This probability is determined by a complex solution to a classical boundary value problem on a contour in the complex time plane. In the case of small particle number it is the probability of instanton-like processes in particle collisions. We obtain numerically configurations with the correct topological features and expected properties in the complex time plane. Our work demonstrates the feasibility of the numerical approach to the calculation of instanton-like processes in gauge theories. We present our preliminary results for the suppression factor of topology changing processes, which cover a wide range of incoming particle numbers and energies below the sphaleron energy.

hep-ph↗

arXiv1999

Periodic Instantons in SU(2) Yang-Mills-Higgs Theory

The properties of periodic instanton solutions of the classical SU(2) gauge theory with a Higgs doublet field are described analytically at low energies, and found numerically for all energies up to and beyond the sphaleron energy. Interesting new classes of bifurcating complex periodic instanton solutions to the Yang-Mills-Higgs equations are described.

hep-ph↗

arXiv1996

On Spherically-Symmetric Solutions in the Two-Higgs Standard Model

We report the results of a numerical search for non-topological solitons in the two-Higgs standard model, characterized by the non-trivial winding, $π_3(S^3)$, of the relative phase of the two doublets. In a region of (weak-coupling) parameter space we identify a branch of winding solutions, which are lower in energy than the embedded standard sphaleron and deformed (bi)sphalerons. Contrary, however, to what happens in 2d toy models, these solutions remain unstable even for very large Higgs masses.

hep-ph↗