Related papers: Probing Delta structure with pion electromagnetic …
We present a relativistic dynamical model of pion photoproduction on the nucleon in the resonance region. It offers several advances over the existing approaches. The model is obtained by extending our $\pi N$-scattering description to the…
We develop a model for the weak pion production off the nucleon, which besides the Delta pole mechanism (weak excitation of the $\Delta(1232)$ resonance and its subsequent decay into $N\pi$), includes also some background terms required by…
A large set of cross sections for semi-inclusive electroproduction of charged pions ($\pi^\pm$) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared $W^2$ > 4…
We derive the separate helicity amplitudes involving the partial wave analysis in the process of pseudo-scalar meson photon productions with $J^P=3/2^+$, which is independent on model. According to parity, the general amplitude in the case…
Photo- and electroproduction of pions and eta-mesons is studied on the nucleon. The formalism of such reactions is presented including polarization degrees of freedom and theoretical approaches are discussed. In particular, the threshold…
The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it…
We consider two-photon exchange (TPE) in the elastic electron-proton scattering and study the contribution arising from the production of Delta(1232) resonance in the intermediate state. We calculate all three TPE amplitudes (generalized…
We discuss the decay tau^- -> nu_tau pi^- pi^0 gamma in terms of a model with the correct low-energy structure and with the relevant resonance degress of freedom. The nontrivial radiative dynamics becomes visible for large photon momenta…
We present the first measurement of the induced proton polarization P_n in pi^0 electroproduction on the proton around the Delta resonance. The measurement was made at a central invariant mass and a squared four-momentum transfer of W=1231…
We study the one-dimensional spin-1/2 model with nearest and next-to-nearest-neighbor couplings exposed to a homogeneous magnetic field $h_{3}$ and a dimer field with period $q$ and strength $\delta$. The latter generates a magnetization…
We studied the electroproduction of the Delta(1232) resonance via the reaction p(e,e'p)\pi0 at four-momentum transfers Qsq = 2.8 and 4.0 GeV^2. This is the highest Qsq for which exclusive resonance electroproduction has ever been observed.…
A unitary model of the final state kaon pion interaction amplitudes in the B --> K pi pi decays is constructed. The weak decay penguin amplitudes, derived in QCD factorization, are supplemented by phenomenological contributions. The strange…
The amplitudes of the pion electroproduction from the nucleon are derived up to third order in the chiral effective theory including explicit $\Delta$(1232) >. The Q^2 evolutions of weighted integrals of amplitudes are presented.
The beam-helicity asymmetry in associated electroproduction of real photons, $ep\to e\gamma \pi N$, in the $\Delta$(1232)-resonance region is measured using the longitudinally polarized HERA positron beam and an unpolarized hydrogen target.…
We study the pi+- spectra obtained in 2,4,6,8 A GeV Au-Au collisions within the thermal model. We find that the main features of the data can be well described after we include the pions from the decay of the Delta-resonance with medium…
Pion-photoproduction data is examined to check for the nucleon-helicity conservation predicted by asymptotic QCD. The differential cross section shows agreement with constituent-counting rules, and polarization data is not in disagreement…
Two pion effective mass and helicity angle distributions in the charged B-meson decays into three charged pions are studied. The weak decay amplitudes are calculated in the framework of the QCD factorization approximation. The strong…
With the availability of the new neutral pion photoproduction from the proton data from the A2 and CB-TAPS Collaborations at Mainz it is mandatory to revisit Heavy Baryon Chiral Perturbation Theory (HBChPT) and address the extraction of the…
We discuss the difficulties in testing the hadron models by using the N^* parameters extracted from the empirical amplitude analyses of the pi-N and gamma-N reaction data. As an alternative or perhaps a more advantageous approach, we…
The production of the isoscalar Jp = 3+ didelta dibaryon d* by proton inelastic scattering from deuteron targets is described in a double-scattering Glauber approximation. Each scattering changes a target nucleon into a Delta with the help…