Related papers: Effect of Pions in Cosmic Rays
The gluon condensation (GC)-effects in high energy cosmic rays are investigated. After a brief review of the GC, several examples including gamma-, electron-, and positron-spectra in a broad GeV$\sim $TeV region can be explained by the…
A cold relic axion condensate resulting from vacuum misalignment in the early universe oscillates with a frequency \sim m_a, where m_a is the axion mass. We summarize how the properties of photons propagating in such a medium are modified.…
Conditions are found, at which in nuclear matter there may appear a spatially nonuniform $p$ wave $\pi^0$ condensate supplemented by a spatially varying spontaneous magnetization. The pion-nucleon interaction and the anomaly contributions…
The quantum electrodynamical vacuum polarization effects arising in the collision of a high-energy proton beam and a strong, linearly polarized laser field are investigated. The probability that laser photons merge into one photon by…
Axionlike particles (ALPs) could mix with photons in the presence of astrophysical magnetic fields. Searching for this effect in gamma-ray observations of blazars has provided some of the strongest constraints on ALP parameter space so far.…
While star-forming galaxies could be major contributors to the cosmic GeV $\gamma$-ray background, they are expected to be MeV-dim because of the "pion bump" falling off below ~100 MeV. However, there are very few observations of galaxies…
Using the light-front pion wave function based on a Bethe-Salpeter amplitude model, we study the properties of the pion in symmetric nuclear matter. The pion model we adopt is well constrained by previous studies to explain the pion…
We explore the phenomenological consequences of a model with axion-like particles and hidden photons mixing with photons. In this model, the hidden photon is directly coupled to the photon, while the axion coupling is induced by an external…
We account for dynamical spin effects in the holographic light-front wavefunction of the pion in order to predict its mean charge radius, decay constant, spacelike electromagnetic form factor, twist-2 Distribution Amplitude and the…
We present Monte Carlo simulations of radiative transfer in magnetar atmospheres. We include the effects of vacuum polarization, electron and proton scattering, and free-free absorption. Simulations are performed for the atmosphere model…
The electric alpha and magnetic beta pion Compton polarizabilities characterize the pion's deformation in the electromagnetic field of the gamma during gamma-pi Compton scattering. The chi_PT effective Lagrangian, using data from radiative…
The propagation of electromagnetic waves in a Lorentz-symmetry violating scenario where there is a region of polarized vacuum is studied. It turns out that the photon field acquires an interesting polarization state, possibly useful to set…
We study pion and kaon condensation using three-flavor chiral perturbation theory at finite isospin and strangeness quark chemical potentials {\mu}I and {\mu}S . The phase diagram consists of a vacuum phase and three distinct Bose condensed…
We use a diffusive model for the propagation of Galactic cosmic rays to estimate the charged pion production in interactions with protons of the interstellar medium. Cosmic ray nuclei from proton to iron are considered and the corresponding…
Very high energy (VHE, energy >~ 100 GeV) {\gamma}-rays originating from extragalactic sources interact with low energy photons of background radiation fields and produce electron-positron pairs. Alternatively, in the presence of ambient…
The decays of pions, the lightest particles composed of quarks, provide important insight into fundamental questions in particle physics including basic symmetries, the universality of fermionic weak interactions, and aspects of the strong…
We investigate the influence of the real part of the in-medium pion optical potential on the pion dynamics in intermediate energy heavy ion reactions at 1 GeV/A. For different models, i.e. a phenomenological model and the $\Delta$--hole…
Understanding the effects of a background hadronic medium on hadronic observables is important in the context of hadron structure. Many experiments probing nucleon structure make use of nuclear targets and unraveling the modifications that…
Recent studies on meson condensations (pions and kaons) in high-density hadronic matter are reviewed. After summarizing onset mechanisms of pion and kaon condensations, we discuss implications for neutron star phenomena such as rapid…
We solve the coupled system of Dyson-Schwinger and Bethe-Salpeter equations for the quark propagator and the pion Bethe-Salpeter amplitude on a finite volume. To this end we use a truncation scheme that includes pion cloud effects in the…