The purpose of this Letter is to prove that, contrary to a widespread belief, photons can be localized in space with an exponential falloff of the photon energy density and of the photodetection rates. In that respect, photons are not much different from massive particles. The only constraint on the photon localizability comes from the fundamental Paley-Wiener theorem [1]. The mathematical mech...

This Letter applies the concept of "jets," as constructed from calorimeter cell four-vectors, to jets composed (primarily) of photons (or leptons). Thus jets become a superset of both traditional objects such as QCD jets, photons, and electrons, and more unconventional objects such as photon jets and electron jets, defined as collinear photons and electrons, respectively. Since standard objects...

The physics of kinetic mixing between ordinary and mirror photons is elucidated. An important role is played by four linear combinations we dub the physical photon, the sterile photon, the physical mirror photon, and the sterile mirror photon. Because of the mass degeneracy between the two gauge bosons, quantum coherence effects are important. The physical photon becomes a certain coherent supe...

The influence of static gravitational field on frequency, wavelength and velocity of photons and on the energy levels of atoms and nuclei is considered in the most elementary way. The interconnection between these phenomena is stressed.

A parametric down conversion source pumped by a monochromatic laser will produce frequency entangled photon pairs. We demonstrate this by an experiment in which five-dimensional frequency entanglement is manipulated at telecommunication wavelengths using commercially available components such as electro-optic phase modulators and narrowband frequency filters. A theoretical intuition for this ap...

We demonstrate that it is possible to localize photons nonreciprocally in a moving photonic lattice made by spatiotemporally modulating the atomic response, where the dispersion acquires a spectral Doppler shift with respect to the probe direction. A static defect placed in such a moving lattice produces a spatial localization of light in the band gap with a shifting frequency that depends on t...

The DGLAP improved color dipole approach provides a good description of data for inclusive direct photon spectra at the energies of RHIC and Tevatron. Within the same framework we predict the transverse momentum distribution of direct photons at the CERN LHC energies.

Researchers have studied electron-positron (e+e-) collisions for interactions that produce a normal photon γ and a dark photon A′ that interacts with ordinary matter particles. The dark photon can potentially decay into an e+epair (shown here) or a μ+μpair (not shown). However, the latest results from the BaBar collaboration offer no sign of dark photons, thus placing new limits on these types ...