The leading-twist valence-quark distribution function in the pion is obtained at a low normalization scale of an order of the inverse average size of an instanton ρc. The momentum dependent quark mass and the quark-pion vertex are constructed in the framework of the instanton liquid model, using a gauge invariant approach. The parameters of instanton vacuum, the effective instanton radius and q...

The MiniBooNE experiment has prepared an almost pure beam of muon-neutrinos over an energy range of a few-hundred MeV to a few GeV with a sample of roughly one-million neutrino interactions. Detailed cross-section measurements have been performed spanning 89% of the total neutrino-interaction rate. Specifically, three single-pion production mechanisms have been measured in detail. These measure...

We argue that the effective pion mass in nuclear matter obtained from chiral effective lagrangians is unique and does not depend on off-mass-shell extensions of the pion fields as e.g. the PCAC choice. The effective pion mass in isospin symmetric nuclear matter is predicted to increase slightly with increasing nuclear density, whereas the effective time-like pion decay constant and the magnitud...

We have developed a field theory formalism to calculate in-medium properties of hadrons within a unified approach that exploits a single Lagrangian to describe simultaneously both matter and meson fluctuations. In this paper , we study the pion velocity v π , which controls through a dispersion relation , the pion propagation in the medium. The v π is defined in terms of parameters related to t...

We study the pion production in heavy-ion collisions at SIS energies within the coupled resonance BUU model. The standard calculation overpredicts the pion multiplicity in the central Au+Au collision at 1 A GeV by about a factor of 2, which is interpreted as a signature for the quenching of the resonance production/absorption in nucleon-nucleon collisions at high nuclear density. Results of the...

The STAR experiment at RHIC has measured a variety of inclusive hadron cross sections in p + p collisions at √ s = 200 GeV. Measurements of the differential cross section for inclusive charged pion production at mid rapidity and for inclusive neutral pion production at forward rapidity (3.0 < η < 4.2) as well as the first preliminary result from STAR for the differential cross section for inclu...

The energy dependence of forward pion double charge exchange reactions on light nuclei is studied for both the Ground State transition and the Double-Isobaric-Analog-State transitions. A common characteristic of these double reactions is a resonance-like peak around 50 MeV pion lab energy. This peak arises naturally in a two-step process in the conventional pion-nucleon system with proper handl...

We present an analysis of QCD sum rules for pion form factor in next-to-leading order of perturbation theory for the case of pseudoscalar pion currents. The essential instanton contribution is reanalysed with account for present more accurate values of parameters entering Single Instanton Approximation (SIA). The theoretical curve obtained for Q 2 dependence of pion form factor is in a good agr...

We give a brief review on the important role of the pion-exchange interaction characterized by the strong tensor force. In order to illustrate the role of the pion, we have proposed a new mean field theory with the charge and parity mixing, by which the pion is treated explicitly in the mean field framework. We introduce the essence of the new mean field theory and illustrate the calculated res...