One of the most successful models of ionization is the photo-absorption ionization model . The model assumes that the process of interest is dominated by single-photon exchange which allows one to relate the ionization process to the photo-absorption process for which the data is more readily available. Also the model is restricted to non-relativistic recoil electron, thus it does not include h...

The photon production due to conversion of two gluons into a photon, $gg\rightarrow\gamma$, in the presence background gauge fields is studied within specific mean-field approach QCD vacuum. In this approach, mean field confinement phase represented by statistical ensemble almost everywhere homogeneous abelian (anti-)self-dual gluon configurations, while deconfined can be characterized purely c...

The photon production rate from a chemically equilibrating quark-gluon plasma likely to be produced at RHIC (BNL) and LHC (CERN) energies is estimated taking into account bremsstrahlung. The plasma is assumed to be in local thermal equilibrium, but with a phase space distribution that deviates from the Fermi or Bose distribution by space-time dependent factors (fugacities). The photon spectrum ...

We study electron-positron in-flight annihilation as a potential source of quasi-monoenergetic photon (or gamma-ray) beams. A high-intensity tunable-energy (1.515 MeV) gamma source has many potential uses in medical, industrial and security applications. Several electron-positron collision geometries are considered: a) head-on; b) collinear; and c) positron beam incident on a fixed electron tar...

Combined experimental and theoretical efforts in the past few years have led to an improved understanding of the unpolarized parton distributions f(x,Q) and the helicity distributions ∆f(x,Q) of the nucleon. It is known that the complete understanding of the partonic structure of a spin 1 2 object like a nucleon is given in terms of f(x,Q), ∆f(x,Q) and by the transversity distributions δf(x,Q),...

An overview of the latest results of the LEP collaborations on QCD measurements in photon-photon collisions is presented, including measurements of the total hadronic cross-section, the production of heavy quarks and dijets and the structure functions of real and virtual photons.

The spectroscopy and photo-induced dissociation of flavin mononucleotide anions in vacuo are investigated over the 300–500 nm wavelength range. Comparison dependence fragment ion yields as a function deposited photon energy with calculated energies collision-induced measurements performed under single-collision conditions suggests that substantial fraction photo-activated ions decompose through...

Acceleration of polarized protons in Relativistic Heavy Ion Collider (RHIC) provides unique tool to study the spin structure of the nucleon. We give a brief overview of the PHENIX program to investigate poorly known gluon and flavor decomposed see quark polarization in the proton, utilizing polarized proton collisions at RHIC. We report PHENIX first results on transverse single-spin asymmetry i...

In hadrons and nuclei at very small x, parton distributions saturate at a scale Qs(x). Since the occupation number is large, and Qs(x) >> ΛQCD, classical weak coupling methods may be used to study this novel regime of non–linear classical fields in QCD. In these lectures, we apply these methods to compute structure functions in deeply inelastic scattering (DIS) and the energy density of gluons ...

The emission of ee pairs from C+C collisions at an incident energy of 1 GeV per nucleon has been investigated. The measured production probabilities, spanning from the π-Dalitz to the ρ/ω invariant-mass region, display a strong excess above the cocktail of standard hadronic sources. The bombarding-energy dependence of this excess is found to scale like pion production, rather than like eta prod...