Related papers: Helicity amplitude method for two electron positro…
The exclusive photoproduction of lepton pairs on nucleon and nucleus target is investigated within the high energy color dipole approach, where the main physical quantity is the dipole-target elastic scattering amplitude that captures the…
Data from the Large Electron Positron collider (LEP) at CERN on hadron production in gamma-gamma interactions exceed the predictions of the standard model by an order of magnitude at the highest observed transverse momenta in three…
The exclusive photoproduction of a pair of light mesons is studied within the framework of collinear factorisation. The amplitude factorises into a process-dependent perturbatively calculable hard part, a generalised parton distribution…
The amplitude for production of a single photon associated with quark pair in the fusion of two off-shell gluons is calculated. The matrix element found is applied to the inclusive prompt photon hadroproduction at high energies in the…
Single $W$-boson production in $e^-\gamma$ collisions with polarized beams is investigated. Helicity amplitudes for general couplings are derived and their properties are discussed. The results are applied to the Standard Model (SM) and the…
Exclusive production of neutrinos via photon-photon fusion provides an excellent opportunity to probe electromagnetic properties of the neutrinos at the LHC. We explore the potential of processes pp-> p gamma gamma p -> p nu anti-nu p and…
The amplitudes for photoproduction of two pseudoscalars on a nucleon are expanded in the overall c.m. frame in a model independent way with respect to the contribution of the final state partial wave of total angular momentum $J$ and its…
A complete parton level analysis of 2l2v2j and 4l2j, l = mu,e production at the LHC is presented, including all processes at order alpha^6, alpha^4*alpha_s^2. The infinite Higgs mass scenario, which is considered as a benchmark for strong…
Knowledge of two-loop QCD amplitudes for processes $q\bar q \to V_1 V_2 \to (l_1\bar l'_1)(l_2 \bar l'_2)$ is important for improving the theoretical description of four-lepton production in hadron collisions. In this paper we compute these…
Optical readout of Gas Electron Multipliers (GEM) provides very interesting performances and has been proposed for different applications in particle physics. In particular, thanks to its good efficiency in the keV energy range, it is being…
High intensity back-scattered laser beams will allow the efficient conversion of a substantial fraction of the incident lepton energy into high energy photons, thus significantly extending the physics capabilities of an electron-electron or…
The process of pair creation by a photon in a constant and homogeneous electromagnetic field of an arbitrary configuration is investigating. At high energy the correction to the standard quasiclassical approximation (SQA) has been…
We assume the coupling of Axion-like particle (ALP) to diphoton $g_{a\gamma\gamma} \sim 0$ and accomplish detailed analyses for the $\gamma Z$ decay mode of such heavy photophobic ALPs at the high luminosity-Large Hadron Collider (HL-LHC).…
We present the gluon-gluon and photon-gluon helicity amplitudes for color singlet and octet charmonium production in polarized and unpolarized hadron-hadron and photon-hadron collisions.
Various methods of obtaining longitudinally polarized positrons for future linear colliders are reviewed. Special attention is paid to the schemes using circularly polarized high-energy photons for positron production. Most effectively such…
We use aMC@NLO to study the production of four charged leptons at the LHC, performing parton showers with both HERWIG and Pythia6. Our underlying matrix element calculation features the full next-to-leading order $O(\alpha_S)$ result and…
A theoretical description of photon-pair production in polarized positron-electron annihilation is presented. Complete one-loop electroweak radiative corrections are calculated taking into account the exact dependence on the electron mass.…
Using a covariant diagram technique and the concept of a nucleus as an elementary particle we calculated differential cross-sections for two-particle photodisintegration reactions of the He-4. The only functional parameter was the vertex…
A model of $\pi N$ pair photoproduction on nuclei at high momentum transfer is presented. The $A(\gamma,\pi N)B$ reaction amplitude is obtained by means of an extended impulse approximation, according to which the nuclear wavefunction…
The collinear factorization framework allows to describe the exclusive photoproduction of a $\gamma\,\rho$ pair in the generalized Bjorken regime in terms of a perturbatively calculable coefficient function and universal generalized parton…