相关论文: On hard exclusive reactions in the time-like regio…
The electromagnetic form factors of the proton in the time-like region and two-photon annihilations into proton-antiproton are investigated. To calculate these processes at moderately large $s$ we use a variant of the Brodsky-Lepage…
The analysis of the $\pi\gamma$ transition form factor provides severe constraints on the pion's wave function. This information is used to examine charmonium decays into two pions critically. It will be argued that the standard…
Massless perturbative QCD forbids, at leading order, the exclusive annihilation of proton-antiproton into some charmonium states, which, however, have been observed in the $p\bar p$ channel, indicating the significance of higher order and…
I survey a number of interesting tests of quantum chromodynamics at the amplitude level which can be carried out in electron-positron annihilation and in photon-photon collisions at low energy, including measurements of fundamental…
It is generally assumed that due to factorization of long- and short-distance dynamics perturbative QCD can be applied to exclusive hadronic reactions at large momentum transfers. Within such a perturbative approach diquarks turn out to be…
In the context of hard hadronic reactions diquarks are a useful phenomenological device to model non-perturbative effects still observable in the kinematic range accessible by present-day experiments. In the following we present…
The role of power corrections and higher Fock-state contributions to exclusive charmonium decays will be discussed. It will be argued that the J/Psi (Psi') decays into baryon-antibaryon pairs are dominated by the valence Fock-state…
We develop perturbative QCD factorization theorems for the exclusive semileptonic heavy baryon decay $\Lambda_b \to pl{\bar\nu}$, in which the relevant hadronic form factor is expressed as the convolution of a hard subamplitude with the…
Data on hyperon form factors recently obtained from annihilation reactions are compared each other, and to proton and neutron form factors, in terms of two kinematical variables: the transferred momentum square, $q^2$, and the modulus $P$…
Recent experimental progress on baryonic rare decays has spurred a deeper investigation on flavor-changing neutral current transitions in the baryon sector. Within the framework of QCD sum rules, we derive a complete set of form factors for…
Motivated by recent advances in experimental measurements of heavy baryon decays, the charmonium decays of single $b$-baryon are investigated systematically in the framework of perturbative QCD approach. We calculate the decay branching…
The annihilation of a lepton pair into a proton-antiproton pair, and the reverse process, allow for a measurement of the timelike proton form factors. This work aims at studying the corrections due to direct soft interactions between the…
The present status of the diquark model for exclusive reactions at moderately large momentum transfer is reviewed. That model is a variant of the Brodsky-Lepage approach in which diquarks are considered as quasi-elementary constituents of…
Exclusive decays of the $\Xi_{bc}^+$ with light mesons production, $\Xi_{bc}^+\to\Xi_{cc}^{++}\mathcal{R}$ are analyzed. In the framework of the factorization model the matrix elements of the considered reactions are written as a product of…
Recent theoretical results on heavy flavor production and decay in the framework of perturbative QCD are reviewed. This includes calculations for top production at hadron colliders, inclusive charmonium production and the comparison between…
I present a mini-review on the physics of heavy flavour baryons where I concentrate on the HQET description of their exclusive decay modes. In particular I discuss the structure of current-induced bottom baryon to charm baryon transitions,…
We study baryon pair production in two-photon collisions, gamma gamma -> B Bbar, within perturbative quantum chromodynamics, treating baryons as quark-diquark systems. We extend previous work within the same approach by treating…
We analyze hadrochemical freeze-out in central Pb+Pb collisions at CERN SPS and LHC energies. We determine the effects of baryon and antibaryon annihilation and/or regeneration occurring during the final cascade expansion stage of the…
New possibilities of high precision measurements of hadron form factors in annihilation and scattering reactions over an unexplored kinematical region suggest a compared analysis, in view of a global description of the nucleon structure.
The data on the proton form factors in the time-like region from the BaBar, BESIII and CMD-3 Collaborations are examined to have coherent pieces of information on the proton structure. Oscillations in the annihilation cross section,…