相关论文: Hard exclusive pion electroproduction at backward …
In this letter we present the first measurements of an exclusive electron neutrino cross section with the MicroBooNE experiment using data from the Booster Neutrino Beamline at Fermilab. These measurements are made for a selection of…
Exclusive production of dielectron pairs, $\gamma\gamma\rightarrow e^+e^-$, is studied using $\mathcal{L}_\mathrm{int}=1.72\; \mathrm{nb^{-1}}$ of data from ultraperipheral collisions of lead nuclei at $\sqrt{s_{_{\text{NN}}}} = 5.02$ TeV…
The differential cross section for the reaction p(gamma, eta p) has been measured from threshold to 1100 MeV photon laboratory energy. For the first time, the region of the S11(1535) resonance is fully covered in a photoproduction…
We develop a non-perturbative analysis of the electro-production of heavy vector mesons ($\phi$, $J/\Psi$) from threshold to high energy. We use the holographic construction with bulk confinement enforced through a soft wall. Using Witten…
We show within proton hot spot picture that the exclusive vector meson production in electron-proton deeply inelastic scattering is sensitive to the individual width of the constituent quarks of the proton. For comparison, we calculate the…
We present measurements of the ep->ep pi^0 cross section extracted at two values of four-momentum transfer Q^2=1.9 GeV^2 and Q^2=2.3 GeV^2 at Jefferson Lab Hall A. The kinematic range allows to study the evolution of the extracted hadronic…
The wide-angle photo- and electroproduction of pions is investigated within the handbag mechanism in which the $\gamma^{(*)} N\to \pi N'$ amplitudes factorize into subprocess amplitudes,$\gamma^{(*)} q\to \pi q'$, and form factors…
Weak pion production off the nucleon at low energies has been systematically investigated in manifestly relativistic baryon chiral perturbation theory with explicit inclusion of the $\Delta$(1232) resonance. Most of the involved low-energy…
Measurements of inclusive differential cross sections for charged pion and kaon production in electron-positron annihilation have been carried out at a center-of-mass energy of Q = 10.52 GeV. The measurements were performed with the Belle…
We have extended a model for the $\gamma N\to \pi\pi N$ reaction to virtual photons and selected the diagrams which have a $\Delta$ in the final state. With this model we have evaluated cross sections for the virtual photon cross section as…
Electroproduction of pions on the nucleon near the threshold is analyzed within the framework of baryon chiral perturbation theory. We give a thorough discussion of the low--energy theorems related to charged and neutral…
Experiments at HERA looking for deep-inelastic electroproduction of neutrons in the proton fragmentation region are in progress. They are aimed to measure the pion structure function at small Bjorken $x$. The important condition for such a…
A general analysis of polarization phenomena for coherent meson electroproduction on deuterons, $e+ d\to e+ d +P^0$, where $P^0$ is a pseudoscalar $\pi ^0$ or $\eta$-meson, is presented. The spin structure of the electromagnetic current for…
Measurements of double-differential charged pion production cross-sections in interactions of 12 GeV/c protons on O_2 and N_2 thin targets are presented in the kinematic range 0.5 GeV/c < p_{\pi} < 8 GeV/c and 50 mrad < \theta_{\pi} < 250…
We evaluate perturbative next-to-leading order corrections to the hard exclusive leptoproduction of pi+ mesons on a transversely polarized proton target. A model dependent study shows that these corrections can be large. We analyze the…
We consider pion electroproduction close to threshold for $Q^2$ in the region 1-10 GeV$^2$ on a nucleon target. The momentum transfer dependence of the S-wave multipoles at threshold, $E_{0+}$ and $L_{0+}$, is calculated in the chiral limit…
A first measurement is presented of exclusive photoproduction of $\rho^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years $2006$ and $2007$ at a centre-of-mass energy of $\sqrt{s}=319$…
Recent developments in phenomenological analysis of the CLAS data on 2$\pi$ electroproduction are presented. The contributions from isobar channels and $P_{11}(1440)$, $D_{13}(1520)$ electrocouplings at $Q^{2}$ from 0.25 to 0.6 GeV$^2$ were…
Exclusive pi0 electroproduction from nucleons can be related to transversity, the tensor charge, and other quantities related to transversity. This process isolates C-parity odd and chiral odd combinations of t-channel exchange quantum…
A first measurement is presented of exclusive photoproduction of $\rho^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years $2006$ and $2007$ at a centre-of-mass energy of $\sqrt{s}=319$…