Related papers: Transition from real to virtual polarized photon s…
The response of matter to an optical excitation consists essentially of absorption and emission. Traditional spectroscopy accesses the frequency-resolved and time-integrated response, while the temporal evolution stays concealed. However,…
In this work, we explore the polaron and molecule physics by utilizing a unified variational ansatz with up to two particle-hole(p-h) excitations(V-2ph). We confirm the existence of a first-order transition in 3D and 2D Fermi polarons, and…
In this report we present the status of the Mainz group's lattice QCD calculation of the pion transition form factor, which describes the interaction of an on-shell pion with two off-shell photons. This form factor is the main ingredient in…
The rare three body decay of a Higgs boson to a lepton-anti lepton pair and a photon has begun to attract attention, after the first evidence for the $H\to Z\gamma$ at CMS and ATLAS, which is a sub process of $H \to \ell^+ \ell^- \gamma$ .…
The unique nature of the photon can be investigated in hitherto unexplored kinematic regions at LEP2. We discuss the theoretical significance of deep inelastic measurements and present a prescription that allows a theoretically and…
We extend the QCD sum rule analysis of the \gamma^*\gamma^* -->\pi^o form factor into the region where one of the photons has small virtuality: q^2 << Q^2 > 1 GeV^2. In this kinematics, one should perform an additional factorization of…
We investigate the singly virtual transition form factor (TFF) for the $\pi^0\to\gamma^*\gamma$ process in the space-like region using the hard-scattering formalism within the Basis Light-Front Quantization (BLFQ) framework. This form…
A simple method is used to extrapolate the form factor for the process gamma* gamma *--->pi^0 when two virtual photons produce a pi ^0 from the region of large spacelike photon virtualities to the experimentally accessible case when one of…
We perform the Hamiltonian analysis of an on-shell U(1) gauge field theory, in which the action is not invariant under local U(1) transformations but recovers the invariance when the equations of motion are imposed. We firstly apply Dirac's…
In this work, we try to understand the transverse structure of photon through transverse momentum dependent parton distribution functions (TMDs) in quantum chromodynamics. We calculate all the possible time reversal photon TMDs using…
A description of the virtual photon absorption cross section difference \sigma_{1/2}-\sigma_{3/2} for the proton and the neutron is obtained with a parameterisation based on a Regge type approach. The parameterisation is obtained from…
In order to examine the validity of Wandzura-Wilczek relation for the polarized DIS structure function $g_2(x,Q^2)$, we use the light-front time-ordering pQCD to calculate $g_2(x,Q^2)$ at order $\alpha_s$ on a quark target. We find that the…
The QCD treatment of the photon structure is recalled. Emphasis is given to the recently derived momentum sum rule, and to the proper choice of the factorization scheme and/or boundary conditions for the evolution equations beyond the…
In a vacuum first-order phase transition, gravitational waves are generated from collision of bubbles of the true vacuum. The spectrum from such collisions takes the form of a broken power law. We consider a toy model for such a phase…
We are studying the electron scattering process e p to e' p' gamma in order to obtain information on the genuine virtual Compton scattering (VCS) process gamma^* N to gamma N. In addition to the two kinematical variables of real Compton…
We report on a recent calculation of the generalized parton distributions (GPDs) of the photon when the momentum transfer in the transverse direction is non-zero. We use an overlap representation of the photon GPDs in terms of the photon…
We report a Virtual Compton Scattering study of the proton at low CM energies. We have determined the structure functions $P_{LL}-P_{TT}/\epsilon$ and $P_{LT}$, and the electric and magnetic Generalized Polarizabilities (GPs) $\alpha_E(Q2)$…
We derive the light-front wave function (LFWF) representation of the $\gamma^* \gamma^* \to \eta_c(1S)\,,\eta_c(2S)$ transition form factor $F(Q_1^2, Q_2^2)$ for two virtual photons in the initial state. For the LFWF, we use different…
We examine the QCD corrections to the structure functions $F_2^\gamma(x,Q^2)$ and $F_L^\gamma(x,Q^2)$ for a real photon target. The pointlike photon contributions from light and heavy quarks are computed through $O(\alpha\alpha_S)$. A…
We study the scaling regime of hadron-(anti)-hadron annihilation into a deeply virtual photon and a real photon, H anti-H -> gamma^* gamma, and deep backward virtual Compton scattering, gamma^* H -> H gamma. We advocate that there is a…