We discuss scattering of fundamental matter in the planar and strong coupling limit via the AdS/CFT correspondence, generalizing the recently proposed calculation for adjoint matter due to Alday and Maldacena [1]. Color decomposition of quark amplitudes is a key property allowing to repeat the procedure in the case of fundamental matter and to derive the relation of these strong coupling amplit...

We pursue the issue of the local quark-hadron duality at high energies in twoand four-dimensional QCD. A mechanism of the dynamical realization of the quark-hadron duality in two-dimensional QCD in the limit of large number of colors, Nc → ∞, (the ’ t Hooft model) is investigated. We argue that a similar mechanism of dynamical smearing may be relevant in four-dimensional QCD. Although particula...

We analyse ∆C = 2 transitions in the framework of a minimal extension of the Standard Model where either a Q = 2/3 or a Q = −1/3 isosinglet quark is added to the standard quark spectrum. In the case of a Q = 2/3 isosinglet quark, it is shown that there is a significant region of parameter space where D 0 − ¯ D 0 mixing is sufficiently enhanced to be observed at the next round of experiments. On...

Hadron structure studies might be traced back to Fermi-Yang [1] and Sakata models [2]. Gell-Mann [3] and Zweig [4] proposed the quark model of hadrons. Lepton-nucleon deep inelastic scattering (DIS) [5] verified the quark structure of hadrons. However the quark revealed in DIS is found to be different from the quark as a carrier of SU(3) symmetry in Gell-Mann-Zweig model. The former is almost a...