The working group on two photon physics concentrated on three main subtopics: modelling the hadronic final state of deep inelastic scattering on a photon; unfolding the deep inelastic scattering data to obtain the photon structure function; and resonant production of exclusive final states, particularly of glueball candidates. In all three areas, new results were presented.

Exclusive two-photon reactions such as Compton scattering at large angles, deeply virtual Compton scattering, and hadron production in photon-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes and skewed parton distributions. Invited talk presented at Photon 2000 Ambleside, England August 26–31, 2000 ∗Work supporte...

We present exact analytical solutions to study the coherent interaction between a single photon and the mechanical motion of a membrane in quadratic optomechanics. We consider single-photon emission and scattering when the photon is initially inside the cavity and in the fields outside the cavity, respectively. Using our solutions, we calculate the single-photon emission and scattering spectra,...

The photon is one of the fundamental gauge bosons of the Standard Model without self-couplings and without intrinsic structure. It couples to any kind of charged particle, which allows it to fluctuate directly into fermion-antifermion pairs and into bound states, vector mesons, which have the same spin-parity (J = 1−−) as the photon. Photon-photon interactions therefore become possible through ...

Introduction: Scatter radiation is one of the major sources of error in nuclear medicine data processing. Different methods of scatter correction have been introduced in order to improve the quality of data. However the best method is to avoid recording of scatter photons in acquisition. The only difference between scattered and non-scattered photons is the energy. Pulse height analyzer i...

We use the behavior of the photon-photon scattering for photon energies ω less than the electron mass, me, to examine the implications of treating the Euler-Heisenberg Lagrangian as an effective field theory. Specifically, we determine the ω/me behavior of the scattering amplitude predicted by including one-loop corrections to the Euler-Heisenberg effective Lagrangian together with the countert...

In electromagnetically-induced transparency (EIT), the scattering rate of a probe beam is greatly reduced due to destructive interference between two dressed atomic states produced by a strong laser beam. Here we show that a similar reduction in the single-photon scattering rate can be achieved by tuning a probe beam to be halfway between the resonant frequencies of two modes of a cavity. This ...

A brief overview of direct-photon measurements in ultra-relativistic nucleus-nucleus collisions is given. The results for Pb+Pb collisions at √ sNN = 17.3 GeV and for Au+Au collisions at √ sNN = 200 GeV are compared to estimates of the direct-photon yield from hard scattering. Both results leave room for a significant thermal photon component. A description purely based on hard scattering proce...

We present a source of correlated photon pairs that relies on spontaneous parametric scattering in microstructure fiber. Quantum correlations are shown between photon pairs that are generated through four-photon scattering where the pump photons are degenerate at a wavelength of 749 nm and the signal and idler photons are nondegenerate at wavelengths of 761 nm and 737 nm, respectively. Careful ...