Seminar “Hadron Physics”

Date and Time: Friday, 12 November 2021, at 11:00 AM

Venue: online seminar on Zoom, Bogoliubov Laboratory of Theoretical Physics

Link to join the seminar on Zoom

Seminar topic: “Causality principle in three-dimensional field-theoretical equations obtained on the basis of the S-matrix equations of Bogolyubov-Medvedev-Polivanov and their applications for few body systems and in high-energy physics”

Speaker: Machavariani Alexander (LHEP JINR & HEPI TSU, Tbilisi, Georgia)

Abstract:

Taking into account the principle of causality the relativistic equations for the multi-channel hadron scattering amplitudes are derived within the S-matrix method of Bogolyubov. The resulting equations have the form of three-dimensional time-ordered relativistic equations. The form and structure of these three-dimensional relativistic equations does not change if the quark degrees of freedom are taken into account based on the Huang-Weldon formulation, where hadrons are considered as bound states of quarks.
The equivalence of the field-theoretical S-matrix methods of Bogolyubov and Lehman-Simanczyk-Zimmerman is considered.
It is shown that take into account the causality principle in the suggested field-theoretical equations reduces to the special shifts on magnitudes of the momentums in s, u, u, t,t channels. At the same time, unitarity in the s-channel is preserved for equations with and without quark degrees of freedom.
Numerical solutions of the obtained equations do not require additional efforts in comparison with similar Lippmann-Schwinger equations in non-relativistic collision theory. A good description was obtained of the experimental phases of elastic πN and NN scattering in the low energy region Quark-parton model for inclusive generation of particles with large transverse momentum is reproduced using a separable approximation. This made it possible to describe experimental data of the inclusive production of a ρ-meson with a large transverse momentum (<1.5 GeV/s) in a proton-proton collision in the energy region 2.9< √s<64 GeV.