Related papers: Pion structure function at small x from DIS data
We compaWe compare the absorptive corrections to the one pion exchange in $pp\to Xn$ and $ep\to e'Xn$ reactions. It is shown that the absorption is stronger in the case of $pp$ collision. The difference in strength of the absorption for the…
Attention is paid to recent results from the ZEUS Collaboration on the photo- and electro- production of leading neutrons in e^+ p collisions at HERA. Some implications for the structure of the pion and the nucleon are discussed.
In principle, leading neutrons produced in photoproduction and deep-inelastic scattering at HERA have the potential to determine the pion structure function, the neutron absorptive cross section and the form of the pion flux. To explore…
The production of neutrons carrying at least 20% of the proton beam energy ($\xl > 0.2$) in $e^+p$ collisions has been studied with the ZEUS detector at HERA for a wide range of $Q^2$, the photon virtuality, from photoproduction to deep…
We examine the efficacy of pion exchange models to simultaneously describe leading neutron electroproduction at HERA and the $\bar{d}-\bar{u}$ flavor asymmetry in the proton. A detailed $\chi^2$ analysis of the ZEUS and H1 cross sections,…
Partonic structure of constituent quark (or{\it{valon}}) in the Next-to-Leading Order is used to calculate pion structure function. This is a further demonstration of the finding that the constituent quark structure is universal, and once…
A detailed analysis of semi-exclusive diffractive processes in e-p DIS at HERA, with the diffractive final states in the forward direction is presented. The contributions of the subleading f_2, \omega, a_2, \rho reggeons and the pion…
Differential cross sections for dijet photoproduction and this process in association with a leading neutron, e+ + p -> e+ + jet + jet + X (+ n), have been measured with the ZEUS detector at HERA using an integrated luminosity of 40 pb-1.…
Despite its theoretical and practical importance, the pion structure is still badly constrained, particularly at low $x_{\pi}$ and in the sea-quark and gluon sectors. Recently ZEUS have presented data on dijet photoproduction with a leading…
Energetic neutrons produced in $ep$ collisions at HERA have been studied with the ZEUS detector in the photoproduction regime at a mean photon-proton center-of-mass energy of 220 GeV. The neutrons carry a large fraction $0.64 < x_L <0.925$…
The "triple-Regge" analysis of subleading Reggeon contributions to the diffractive structure function in DIS at HERA is presented. The recently published data allow to estimate the only free parameter of the analysis related to the ratio of…
The zero-degree calorimeters (ZDC) installed in the ALICE, ATLAS and CMS experiments at the LHC, make possible simultaneous detection of forward-backward leading neutrons, pp=>nXn. Such data with sufficiently high statistics could be a…
Neutron structure functions can be extracted from proton and deuteron data and a representation of the deuteron structure. This procedure does not require DIS approximations or quark structure assumptions. We find that the results depend…
Measurements of proton structure functions made in neutral and charged current interactions at HERA are discussed, covering four-momentum transfers Q^2 from about 0.5 GeV^2 to 30000 GeV^2. The results include the rise of the structure…
The QCD hardness scale for secondary particles ($h$) production in semi-inclusive deep inelastic scattering (DIS), $e p \to e' X h$, gradually decreases from $Q^{2}$, the photon virtuality which determines the hard scale in the virtual…
Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm. A cut on xg, the fraction of the photon energy participating in the production of the two jets of…
A recent reanalysis of world proton and deuteron structure function measurements showed that a significant amount of the apparent model dependence in the extraction of the neutron structure function was related to inconsistencies between…
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 319 GeV and…
The dependence of dijet production on the virtuality of the exchanged photon, Q^2, has been studied by measuring dijet cross sections in the range 0 < Q^2 < 2000 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 38.6…
The inclusive cross section for the photoproduction of neutral pions has been measured as a function of the transverse momentum, rapidity, and Feynman x of the pizero mesons at an average photon--proton centre-of-mass energy of 208 GeV and…