Related papers: DIS2021 Workshop Proceedings: Backward-Angle (u-Ch…
Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this letter, we present the first…
The proposed measurement is a dedicated study of the exclusive electroproduction process,1H(e,e'p)pi0, in the backward-angle regime (u-channel process) above the resonance region. The produced pi0 is emitted 180 degrees opposite to the…
In backward photoproduction of mesons, $\gamma p\rightarrow M p$, the target proton takes most of the photon momentum, while the produced meson recoils in the direction from which the photon came. Thus the Mandelstam $u$ is small, while the…
The proposed measurement is a dedicated study to investigate the exclusive electroproduction process: 1H(e, e'p)X, in the backward angle above the resonance region. Here, the produced particle X (pi0 or gamma) is emitted 180 degrees…
Exclusive electroproduction of pi0 mesons on protons in the backward hemisphere has been studied at Q**2 = 1.0 GeV**2 by detecting protons in the forward direction in coincidence with scattered electrons from the 4 GeV electron beam in…
Backward photoproduction of $\omega$ off a proton target is investigated in a Reggeized model where the $u$-channel nucleon Reggeon is constructed from the nucleon Born terms in a gauge invariant way. The $t$-channel meson exchanges are…
We propose to study the onset of color transparency in hard exclusive reactions in the backward regime. Guided by the encouraging JLab results on backward pion and omega electro-production data at moderate Q^2, which may be interpreted as…
We consider backward vector meson exclusive electroproduction off nucleons in the framework of collinear QCD factorization. Nucleon to vector meson transition distribution amplitudes arise as building blocks for the corresponding factorized…
At large virtuality $Q^2$, the coupling to the $\rho$ meson production channels provides us with a natural explanation of the surprisingly large cross section of the $\omega$, as well as the $\pi^+$, meson electroproduction recently…
High-energy backward ($u$-channel) reactions can involve very large momentum transfers to the target baryons, shifting them by many units of rapidity. These reactions are difficult to understand in conventional models in which baryon number…
The electroproduction of $\eta '$ mesons from a $\mathrm{^{1}H}$ target at $W=2.13~\text{GeV}$, $Q^{2} = 0.46~\left( \text{GeV}/c\right)^{2}$ and $\cos \theta^{\text{CM}}_{\gamma^{*}\eta'} \approx -1$ has been experimentally measured. The…
Mesons' internal structure and dynamics may be accessed through hard exclusive electroproduction processes such as deeply virtual Compton scattering in both near forward and near backward kinematics. With the help of the Sullivan process…
Advances in the exploration of the spectrum and structure of the excited states of the nucleon from experiments with electromagnetic probes on proton targets are presented. Impressive progress has been achieved in the studies of exclusive…
This work is a pioneering study of backward-angle omega cross sections through the exclusive 1H(e,e'p)omega reaction using the missing mass reconstruction technique. The extracted cross sections are separated into the transverse (T),…
The data were accumulated with the HERMES forward spectrometer using the 27.6 GeV longitudinally polarized electron or positron beam of HERA. Exclusive electroproduction of $\omega$ mesons on unpolarized hydrogen and deuterium targets is…
Electroproduction of the omega meson was investigated in the p(e,e'p)omega reaction. The measurement was performed at a 4-momentum transfer Q2 ~ 0.5 GeV2. Angular distributions of the virtual photon-proton center-of-momentum cross sections…
Differential cross sections and photon beam asymmetries for $\pi^0$ photoproduction have been measured at $E_\gamma$ = 1.5--2.4 GeV and at the $\pi^0$ scattering angles, --1 $<$ cos$\Theta_{c.m.} <$ --0.6. The energy-dependent slope of…
I discuss recent results on the electroproduction and photoproduction of mesons in the region of non-strange baryon resonances. Results on the quadrupole transition from the ground state nucleon to the Delta(1232) show the importance of…
We report the measurement of differential cross sections for $\omega$ and $\eta'$ photoproduction from protons at backward angles ($-1.0<\cos\Theta_{C.M}^{X}<-0.8$) using linearly polarized photons at $E_{\gamma}=$$1.5-3.0$ GeV.…
One principal motivation for studying exclusive reactions is that they provide a new class of observables, called off-diagonal parton distributions, for the internal structure of the nucleon. The study of exclusive reactions provides a…