Related papers: Hard exclusive two photon processes in QCD
We study the exclusive production of pi pi and rho pi in hard gamma* gamma scattering in the forward kinematical region where the virtuality of one photon provides us with a hard scale in the process. The newly introduced concept of…
We compute QCD corrections to the production of a ttbar pair in association with a hard photon at the Tevatron and the LHC. This process allows a direct measurement of the top quark electromagnetic couplings that, at the moment, are only…
We calculate the photoproduction of heavy quarks in proton-proton collisions at RHIC, Tevatron and LHC energies. The integrated cross section and the rapidity distributions for open charm and bottom production are computed employing sound…
Ultrarelativistic heavy ion collisions at the laboratory provide a unique chance to study quantum chromodynamics (QCD) under extreme temperature (${\approx}150\,\mathrm{MeV}$) and density (${\approx}1\,\mathrm{GeV}/\mathrm{fm}^3$)…
We describe the process $\gamma N \to \gamma\,\rho N'$ in the generalized Bjorken regime where the $\gamma\,\rho $ pair has a large invariant mass. In the collinear QCD factorization framework, the amplitude gives access to both chiral-even…
We develop a QCD sum rule analysis of the form factor $F_{\gamma^*\gamma^*\pi^0}(q^2,Q^2)$ in the region where virtuality of one of the spacelike photons is small $q^2 \ll 1 GeV^2$ while another is large: $Q^2 \gapprox 1 GeV^2$. We…
Exclusive proton-antiproton annihilation into two photons can be viewed as the Compton process in the crossed channel. At large s (~10 GeV^2) and |t|,|u| s this process can be described by a generalized partonic picture, analogous to the…
1) Hard exclusive processes in QCD: main characteristic properties; 2) Experimental and theoretical status of the J/Psi and Psi^\prime decays.
The photoproduction of $P$-wave doubly charmed baryon ($\Xi_{cc}$) is investigated in the context of future high-energy and high-luminosity $e^+e^-$ colliders. The direct photoproduction via the sub-process $\gamma+\gamma \rightarrow…
Results of a next-to-leading order calculation of the inclusive cross section for a photon and a heavy quark (charm or bottom), $p \bar p / pp \to \gamma +Q +X$, are presented. Pointlike photon subprocesses through ${\cal…
A unified approach to total cross-sections, based on the QCD contribution to the rise with energy, is presented for the processes $pp$, $p{\bar p}$, $\gamma p, \gamma \gamma, e^+e^- \to hadrons$. For proton processes, a discussion of the…
We investigate the two-photon transitions $H_{c\bar c} \to \gamma^*\gamma$ of the charmonium system in light-front dynamics. The light-front wave functions were obtained from solving the effective Hamiltonian based on light-front holography…
We show that a general two-Higgs-doublet model (THDM) with a very light CP-odd scalar (A) can be compatible with the rho parameter, Br(b --> s\gamma), R_b, A_b, (g-2) of muon, Br(Upsilon --> A gamma), and the direct search via the Yukawa…
The process $p \pbar \rightarrow W^{\pm}\gamma + X \rightarrow \ell^\pm \nu \gamma + X$ is calculated to ${\cal O}(\alpha_s)$ for general $CP$ conserving $WW\gamma$ couplings. At the Tevatron center of mass energy, the QCD corrections to…
Enlarging the set of hard exclusive reactions to be studied in the framework of QCD collinear factorization opens new possibilities to access generalized parton distributions (GPDs). We studied the photoproduction of a large invariant mass…
The recent status of hard thermal photon production in relativistic heavy ion collisions is reviewed and the current rates are presented with emphasis on corrected bremsstrahlung processes in the quark-gluon plasma (QGP) and quark-hadron…
A selected set of topics along the borderline between perturbative and nonperturbative QCD in exclusive reactions are studied. Specific problems, related to different mechanisms of momentum transfer to an intact hadron, are discussed.…
We demonstrate that studies of the semiexclusive large angle photon - nucleus reactions: $\gamma + A\to h_1+h_2 +(A-1)^*$ with tagged photon beams of energies $6 \div 10$ GeV which can be performed in Hall D at Thomas Jefferson National…
The goal of this research is to determine and study a physical system that will enable a fast and intrinsically two-photon detector, which would be of interest for quantum information and metrology applications. We consider two types of…
In this paper, we present a dispersive analysis of the double-virtual photon-photon scattering to two pions up to 1.5 GeV. Through unitarity, this process is very sensitive to hadronic final state interaction. For the $s$-wave, we use a…