Related papers: Additional selection rule for some emission, photo…
We use a kinetic-equation approach to describe the propagation of ultra high energy cosmic ray protons and nuclei and calculate the expected spectra and mass composition at the Earth for different assumptions on the source injection spectra…
In light of the increasingly heavy UHECR composition at the highest energies, as observed by the Pierre Auger Observatory, the implications of these results on the actual source composition and spectra are investigated. Depending on the…
Deviation from standard dispersion relations for electrons and photons in the form of an extra term proportional to an arbitrarily high power of momentum is studied. It is shown that observational constraints lead to a region in the…
The mechanism leading to an Auger transition is based on the residual Coulomb interaction between the valence electron and the core electrons. On the assumption that the wave field is switched on adiabatically, the probability of the Auger…
Photons carrying a well-defined orbital angular momentum have been proven to modify spectroscopic selection rules in atomic matter. Excitation profiles of electric quadrupole transitions have been measured with single trapped $^{40}$Ca$^+$…
We use a kinetic-equation approach to describe the propagation of ultra high energy cosmic ray protons and nuclei comparing theoretical results with the observations of the Pierre Auger Observatory.
The energy spectrum and mass composition of ultra-high energy cosmic rays inferred at the Pierre Auger Observatory are used to derive a benchmark scenario for the emission mechanisms at play in extragalactic accelerators as well as for…
The second order correlation function for light emitted from a strongly and near-resonantly driven dilute cloud of atoms is discussed. Because of the strong driving, the fluorescence spectrum separates into distinct peaks, for which the…
Many models for ultra-high energy cosmic rays postulate exotic scenarios to explain the sources or the nature of these particles. A characteristic feature of these models is the prediction of a significant flux of photons at ultra-high…
A gas of atoms some of which are in excited electronic state is under consideration. Since the lifetime of an excited state is to great extent larger than the time required for establishing the equilibrium over translational degrees of…
We calculate the axion emission rate from reactions involving thermal pions in matter encountered in supernovae and neutron star mergers, identify unique spectral features, and explore their implications for astrophysics and particle…
We report a calculation of the expected rate of inclined air showers induced by ultra high energy cosmic rays to be obtained by the Auger Southern Observatory assuming different mass compositions. We describe some features that can be used…
Proton emission, $\alpha$ decay, and cluster radioactivity play an important role in nuclear physics. We show that high-frequency alternative electric fields could deform Coulomb barriers that trap the charged particle, and raise the…
We discuss the possibility of non-exponential Auger decay of atoms irradiated by X-ray photons. This effect can occur at times, which are greater than the lifetime of a system under consideration. The mechanism for non-exponential depletion…
Twisted photon states, or photon states with large ($> \hbar$) angular momentum projection in the direction of motion, can photoexcite atomic final states of differing quantum numbers. If the photon symmetry axis coincides with the center…
The hypernuclear Auger effect, given by the de-excitation of a Lambda hypernucleus by means of the transition of a Lambda hyperon from an initial to a lower lying final single particle state in conjunction with neutron emission from the…
The dependence of fusion dynamics on neutron excess for light nuclei is extracted. This is accomplished by comparing the average fusion cross-section at energies just above the fusion barrier for $^{12-15}$C + $^{12}$C with measurements of…
A set of electron-correlation energies as large as 10 eV have been measured for a magnetic 2ML Fefilm deposited on Ag(001). By exploiting the spin selectivity in angle-resolved Auger-photoelectroncoincidence spectroscopy and the…
The Pierre Auger Observatory has a unique potential to search for ultra-high energy photons (above ~1 EeV). First experimental limits on photons were obtained during construction of the southern part of the Observatory. Remarkably, already…
An overview of the multi-messenger capabilities of the Pierre Auger Observatory is presented. The techniques and performance of searching for Ultra-High Energy neutrinos, photons and neutrons are described. Some of the most relevant results…