相关论文: Isolated Prompt Photon Production
In this preprint we analyzed the exclusive photoproduction of $\eta_{c}\gamma$ pairs in the collinear factorization framework and evaluated its cross-section in leading order in the strong coupling $\alpha_{s}$. We found that this process…
We complete our earlier study of the "direct" part of the cross section and spin asymmetry for the photoproduction process $\gamma N\rightarrow h X$ by analysing the "resolved" contribution, for which the photon couples like a hadron…
The invariant cross sections for direct photon production in hadron-hadron collisions are calculated for several initial energies (SPS, ISR, S$p \bar p$S, RHIC, Tevatron, LHC) including initial parton transverse momenta within the formalism…
The photoproduction of large-p_T charged hadrons and of prompt photons is discussed, for the inclusive case and with an associated jet, using predictions from the NLO partonic Monte Carlo program EPHOX. Comparisons to recent HERA data are…
It is shown that the yield of relativistic positronium atoms in photoproduction on extended targets is much larger than usually accepted.The cause of such difference is transparent. At high energies, when the positronium atom formation time…
Positivity constraints have proved to be important for spin observables of exclusive reactions involving polarized initial and final particles. Attention is focused in this note on the photoproduction of pseudoscalar mesons from spin 1/2…
Pair production of massive coloured particles in hadron collisions is accompanied by potentially large radiative corrections related to the suppression of soft gluon emission and enhanced Coulomb exchange near the production threshold. We…
Exotic hadrons beyond the conventional quark model have been discovered in the past two decades. Investigations of these states can lead to deep understanding of nonperturbative dynamics of the strong interaction. In this concise review, we…
We investigate the early onset of pionic color transparency ($\pi$CT) observed at Jefferson Laboratory (JLAB) in semi--exclusive pion electroproduction reaction $A(e,e'\pi^+)$ off nuclei. In the present description the primary $\gamma^*p…
Inclusive hadron production cross sections in e+e-collisions shed light on the fundamental fragmentation and hadronization processes. We present measurements of the inclusive spectra of charged pions, kaons and protons in hadronic events at…
The ATLAS experiment at the LHC has measured the production cross section of events with two isolated photons in the final state, in proton-proton collisions at sqrt(s) = 7 TeV. The full data set collected in 2011, corresponding to an…
The productions of the exotic states $ X_0(2900) $ and $ X_1(2900) $ in $K^{+}p \to \Sigma_{c}^{++}X_{0}(2900)$ and $K^{+}p \to \Sigma_{c}^{++}X_{1}(2900)$ reactions are studied within an effective Lagrangian approach. The $t-$channel Born…
We calculate the inclusive cross section for prompt photon production in heavy-ion collisions at RHIC energies ($\sqrt{s}=130$ GeV and $\sqrt{s}=200$ GeV) in the central rapidity region including next-to-leading order,…
The $x$ dependence of hadrons' generalized parton distributions (GPDs) $\mathcal{F}(x,\xi,t)$ is the most difficult to extract from the existing known processes, while the $\xi$ and $t$ dependence are uniquely determined by the kinematics…
The thermal multihadron production observed in different high energy collisions poses two basic problems: (1) why do even elementary collisions with comparatively few secondaries (e+e- annihilation) show thermal behaviour, and 2) why is…
The hypothetic R--resonance production (anomalous "$l\bar l\gamma\gamma$" events at LEP) with 60 GeV mass at FNAL hadron collider has been considered. The cross-section of this R-resonance production with the consequent decay $R \to…
The reactions gamma p -> K+ Lambda and gamma p -> K* Lambda are analyzed within perturbative QCD, allowing for diquarks as quasi-elementary constituents of baryons. The diquark-model parameters and the quark-diquark distribution amplitudes…
We consider the prompt photon production at modern high energy colliders in the framework of $k_T-$factorization approach. We compare our theoretical predictions with recent experimental data at HERA and Tevatron, empahasizing the…
Photon radiation at large transverse momenta at colliders is a detailed probe of hard interaction dynamics. The isolated photon production cross section in deep inelastic scattering was measured recently by the ZEUS experiment, and found to…
Photonic events with large missing energy have been observed in e+e- collisions at centre-of-mass energies of 130, 136, 161 and 172 GeV using the OPAL detector at LEP. Results are presented based on search topologies designed to select…