Related papers: Two-photon annihilation into pion pairs
Estimation of multiplicity of muons and pions production at high energy proton-nuclei collisions is given. Both QED and QCD contributions are considered for peripheral kinematics of muon pair and $\sigma$-meson production, keeping in mind…
The photon pair production by pion annihilation in a hot and dense medium at the chiral phase transition is investigated within a chiral quark model. As a direct consequence of this transition the $\sigma$ meson appears as a bound state in…
High energy multiparticle photoproduction off nuclear targets is studied. The photon is assumed to interact in direct scattering processes or as a resolved $q\bar{q}$-state according to the Generalized Vector Dominance Model. In the…
We revisit the description of pion production in proton-proton collisions in the light of the very precise data taken at the Large Hadron Collider (LHC) over the past decade. First attempts to include LHC results in next-to-leading order…
We consider the charge-odd correlations (COC) in cross sections of processes of production of charged particles. The cases of a muonic pair and pion systems $\pi^{+}\pi^{-},\pi^{+}\pi^{-}\pi^{0}$ are considered in detail for electron-proton…
The reaction $pp \to pp2\gamma$, proposed earlier to probe for the NN--decoupled dibaryon resonances, has been studied by the DIB$2\gamma$ Collaboration (JINR) and their preliminary data seem to give evidence for the resonance effect at…
We present a perturbative calculation of baryon pair production in two-photon collisions, $\gamma \gamma \to B \bar{B}$, in which baryons are treated as quark-diquark systems. Our approach accounts for constituent mass effects in a…
We perform a QCD analysis of the exclusive production of two mesons in gamma^* gamma collisions in the kinematical domain of large photon virtuality Q and small hadronic invariant mass W. This reaction is dominated by a scale invariant…
The position-representation wave function for multi-photon states and its equation of motion are introduced. A major strength of the theory is that it describes the complete evolution (including polarization and entanglement) of…
The differential cross sections for the process $\gamma \gamma \to \pi^0 \pi^0$ have been measured in the kinematic range 0.6 GeV $< W < 4.1$ GeV, $|\cos \theta^*|<0.8$ in energy and pion scattering angle, respectively, in the…
We present a formalism for studying the exclusive production or decay of mesons with any value of the internal orbital angular momentum L. As an application, we discuss the production of meson pairs (involving tensor and pseudotensor…
In the framework of QED, scalar pair production by a single linearly polarized high-energy photon in the presence of an external Aharonov-Bohm potential is investigated. The exact scattering solutions of the Klein-Gordon equation in…
In $\rho^0$ photoproduction in ultra-peripheral heavy ion collisions, either ion can be the photon emitter or the target. The two possibilities are indistinguishable, and they should be able to interfere, reducing $rho^0$ production at low…
We study pair production of scalar top quarks in polarized photon-photon collisions with the subsequent decay of the top squarks into b-quarks and charginos. We simulate this process by using PYTHIA6.4 for an electron beam energy 2E_beam…
We report a study of the processes of coherent a pion and a photon diffraction dissociation into two jets. The structure of non-factorizable contributions in these reactions is discussed. We argue that production of hard dijets by real…
The advent of back-scattered laser beams for electron-positron colliders will allow detailed studies of a large array of high energy photon-photon and photon-electron collision processes with polarized beams. These include tests of…
We present complete results for the $O(\alpha_s)$ corrections to the production of a heavy quark pair plus a hard photon, in $e^+ e^-$ annihilation, including both photon and $Z$ intermediate states. Virtual corrections are calculated…
We explore quark-hadron duality in semi-inclusive pion electroproduction on proton and neutron targets. Using the spin-flavor symmetric quark model, we compute ratios of pi+ and pi- cross sections for both unpolarized and polarized…
We calculate the rate for pair production of light pseudoscalars by strong inhomogeneous and static electric (magnetic) fields. We show that, in the case of axions, the stability of atoms over cosmic lifetimes is jeopardised unless the…
We develop the formalism for coherent two pion photoproduction in nuclei and perform actual calculations of cross sections for $\pi^-\pi^+$ and $\pi^0\pi^0$ photoproduction on $^{12}C$. We find that due to the isospin symmetry the cross…