arXiv subjects

V. I. Zakharov

Publications and source records attributed to V. I. Zakharov.

131 records · Page 8Linked to original sources

arXiv1994

Nambu-Jona-Lasinio Model vs QCD

We argue that the extended Nambu-Jona-Lasinio model which introduces four-quark interactions to describe hadron physics at low energies can be confronted with fundamental quantum chromodynamics by means of spectral sum rules. While there arise rather restrictive bounds on the strength of the effective four-quark interaction in the vector channel, introduction of the four-quark interaction in the pseudoscalar channel resolves a long standing puzzle of the sum rules.

hep-ph↗

arXiv1994

Extended Nambu-Jona-Lasinio Model vs QCD Sum Rules

We argue that the extended Nambu-Jona-Lasinio model of hadrons can be be probed and constrained in a nontrivial way via QCD sum rules. While there arise rather restrictive bounds on the strength of the effective four-fermion interaction in the vector channel, introduction of the four-fermion interaction in the pseudoscalar channel could resolve a long standing puzzle of QCD sum rules. We speculate also on possible connection between effective four-quark interactions describing the low-energy phenomenology and ultraviolet renormalons of the fundamental QCD.

hep-ph↗

arXiv1994

Bloch-Nordsieck cancellations beyond logarithms in heavy particle decays

We investigate the one-loop radiative corrections to the semileptonic decay of a charged particle at finite gauge boson mass. Extending the Bloch-Nordsieck cancellation of infrared logarithms, the subsequent non-analytic terms are also found to vanish after eliminating the pole mass in favor of a mass defined at short distances. This observation justifies the operator product expansion for inclusive decays of heavy mesons and implies that infrared effects associated with the summation of the radiative corrections are suppressed by at least three powers of the mass of the heavy decaying particle.

hep-ph↗

arXiv1994

The Vacuum of de~Sitter Space

To resolve infrared problems with the de~Sitter invariant vacuum, we argue that the history of the de~Sitter phase is crucial. We illustrate how either (1)~the diagonalization of the Hamiltonian for long-wavelength modes or (2)~an explicit modification of the metric in the distant past leads to natural infrared cutoffs. The former case resembles a bosonic superconductor in which graviton-pairing occurs between non-adiabatic modes. While the dynamical equations respect de~Sitter symmetry, the vacuum is not de~Sitter invariant because of the introduction of an initial condition at a finite time. The implications for the one-loop stress tensor and the production of particles are also discussed.

gr-qc↗

arXiv1994

On Infrared Effects in de~Sitter Background

We have estimated higher order quantum gravity corrections to de~Sitter spacetime. Our results suggest that, while the classical spacetime metric may be distorted by the graviton self-interactions, the corrections are relatively weaker than previously thought, possibly growing like a power rather than exponentially in time.

gr-qc↗