相关论文: Propagators of light scalar mesons
We consider field-theoretic models, one consisting purely of scalars, the other also involving fermions, that couple to a set of constant background coupling coefficients transforming as a symmetric observer Lorentz two-tensor. We show that…
A multichannel description of the light scalar mesons in the framework of the Resonance-Spectrum Expansion is generalised by including vector-vector and scalar-scalar channels, besides the usual pseudoscalar-pseudoscalar channels.…
A new type of integral representation is proposed for the propagators of the massive Klein-Gordon field minimally coupled to the gravity of the de Sitter expanding universe. This representation encapsulates the effects of the Heaviside step…
In this work we study the spectral functions of scalar mesons in one- and two-channel cases. When the propagators satisfy the K\"allen-Lehman representation a normalized spectral function is obtained, allowing to take into account…
In a recent paper [1], motivated by forthcoming space experiments involving propagation of light in the Solar System, we have proposed an extention of the IAU metric equations at the c-4 level in General Relativity. However, scalar-tensor…
The light scalar mesons in a variety of approaches are briefly reviewed, as well as their description in the Resonance-Spectrum Expansion and related coupled-channel formalisms. A recent multichannel modelling of the light scalars is…
It is well known that the propagator for a massive scalar field is ill-defined in the coordinate space for $d\geq2$, in particular it diverges at the light-cone; we show that by using Lorentz symmetry breaking weighted measures, an infinite…
We have obtained propagators in the position space as an expansion over Landau levels for the charged scalar particle, fermion, and massive vector boson in a constant external magnetic field. The summation terms in the resulting expressions…
Whether monochromatic, pulsed, or even constant and crossed, the field used to describe the interaction of charged fermions with an intense laser beam is mainly assumed to be of plane-wave form. We consider a simple extension to plane-wave…
Light scalar mesons can be understood as dynamically generated resonances. They arise as 'companion poles' in the propagators of quark-antiquark seed states when accounting for hadronic loop contributions to the self-energies of the latter.…
We provide an analytic propagator for non-Hermitian dimers showing linear gain or losses in the quantum regime. In particular, we focus on experimentally feasible realizations of the $\mathcal{PT}$-symmetric dimer and provide their mean…
The light scalar mesons, discovered over forty years ago, became a challenge for the naive quark-antiquark model from the outset. At present the nontrivial nature of these states is no longer denied practically anybody. Two-photon physics…
Contrary to common belief, the longitudinal vector meson and scalar meson propagators have very different forms in spontaneously broken gauge theories. We choose the Abelian-Higgs model as an example and show that the longitudinal vector…
We show how to obtain information about the states of an effective field theory in terms of the underlying fundamental theory. In particular we analyze the spectroscopic nature of meson resonances from the meson-meson scattering amplitudes…
Within the framework of generally covariant (pre-metric) electrodynamics, we specify a local vacuum spacetime relation between the excitation $H=({\cal D},{\cal H})$ and the field strength $F=(E,B)$. We study the propagation of…
We numerically find that transmission coefficients have a rich structure as a function of wavelength in Cantor media. Complete transmission and complete reflection are observed. We also find that light propagation has scalings with respect…
A relativistic version of the Kubo--Martin--Schwinger boundary condition is presented which fixes the properties of thermal equilibrium states with respect to arbitrary space--time translations. This novel condition is a natural…
We develop a field theory approach to light propagation in a gas of resonant atoms taking into account vector character of light and atom-atom interactions. Within this approach, we calculate the propagator of the electric field for both…
Although studied for many years the nature of the light scalar mesons remains controversial. Here we shall present a method, applicable for s-wave states located close to a threshold, that allows one to quantify the molecular part of a…
This contribution has two main purposes. First, we show using classical optics how to model two coupled quantum harmonic oscillators and two interacting quantized fields. Second, we use quantum mechanical techniques to solve, exactly, the…