arXiv subjects

K. Urbanowski

Publications and source records attributed to K. Urbanowski.

39 records · Page 3Linked to original sources

arXiv2000

Improved Lee, Oehme and Yang approximation

The Lee, Oehme and Yang (LOY) theory of time evolution in two state subspace of states of the complete system is discussed. Some inconsistencies in assumptions and approximations used in the standard derivation of the LOY effective Hamiltonian, H(LOY), governig this time evolution are found. Eliminating these inconsistecies and using the LOY method, approximate formulae for the effective Hamiltonian, H(eff), governing the time evolution in this subspace (improving those obtained by LOY) are derived. It is found, in contradistinction to the standard LOY result, that in the case of neutral kaons ( - ), cannot take the zero value if the total system the preserves CPT--symmetry. Within the use of the method mentioned above formulae for H(eff) acting in the three state (three dimensional) subspace of states are also found.

math-ph↗

arXiv1999

A contribution to the discussion of the matter-antimatter asymmetry problem

Using a more accurate effective Hamiltonian governing the time evolution in the particle-antiparticle subspace of states than the one obtained within the Lee-Oehme--Yang approach we show that in the case of particles created at the initial instant t = 0 only the masses of a stable particle and its antiparticle are the same at all t > 0 in a CPT invariant system, whereas the masses of an unstable particle and its antiparticle are equal only at t = 0 and then during their time evolution they become slightly different for times t >> 0 if CP symmetry is violated but CPT symmetry holds. This property is used to show that if the baryon number B is not conserved then the asymmetry between numbers of unstable baryons and antibaryons can arise in a CPT invariant system at t >> 0 even in the thermal equilibrium state of this system.

hep-ph↗

arXiv1998

CPT transformation properties of the exact effective Hamiltonian for neutral kaon and similar complexes

CPT-symmetry properties of the exact effective Hamiltonian H(eff) governing the time evolution in the K(0), K(O)-bar (neutral K mesons) subspace implied by such properties of the total Hamiltonian of the system under consideration are examined. We show that H(eff) can commute with CPT - operator only if H does not commute with it. We also find that, in contradistinction to the standard result of the Lee-Oehme-Yang (LOY) theory, Re. = Re. , i.e., ( - ) = 0, only if the total system does not preserve CPT-symmetry. Using more accurate approximation than Weisskopf-Wigner approximation, an estimation of the difference ( - ) is found for CPT-invariant generalized Fridrichs-Lee model.

hep-ph↗