2,241 research outputs found
Reggeons in diffractive interactions in deep inelastic scattering at HERA
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 RRP and PPP couplings. The large value of this
ratio is prefered which is in agreement with analyses of soft hadronic
interactions. The role of the subleading Reggeons as well as pions for the fast
forward neutron production in diffractive processes is estimated. The forward
piN state production is also discussed.Comment: 6 pages, 2 figures, uses sprocl.sty and epsfig. To be published in
Proceedings of the Madrid low-x Workshop, Miraflores de la Sierra, June
18-21,199
Geometric scaling for the total gamma^* p cross section in the low x region
We observe that the saturation model of deep inelastic scattering, which
successfully describes inclusive and diffractive data at small x, predicts a
geometric scaling of the total gamma^* p cross section in the region of small
Bjorken variable x. The geometric scaling in this case means that the cross
section is a function of only one dimensionless variable tau = Q^2 R_0^2(x),
where the function R_0(x) (called saturation radius) decreases with decreasing
x. We show that the experimental data from HERA in the region x<0.01 confirm
the expectations of this scaling over a very broad region of Q^2. We suggest
that the geometric scaling is more general than the saturation model.Comment: 12 pages, 4 figures, LaTeX, revised version to appear in journal. 1
new figure, several new references added, extended discussion on saturation
radiu
Redescription des genres Septatrypa KOZLOWSKI, 1929 et Dubaria TERMIER, 1936 (Brachiopoda, Atrypida, Lissatrypidae)
The serial sections carried out on specimens of Septatrypa secreta KOZLOWSKI, 1929 and Dubaria lantenoisi TERMIER, 1936 show that the former of these species has a structure of the type "septalium" in the brachial valve. This "septalium" arises from the presence of an apical thickening which joins the median septum and the posterior and external part of the socket plates. This observation confirms the opinion of the authors who consider these two genera - of which the above species are the type species - to be distinct. The lectotype of Dubaria lantenoisi is designated. Some controversial genera of Septatrypinae are briefly discussed
Quark model with chiral-symmetry breaking and confinement in the Covariant Spectator Theory
We propose a model for the quark-antiquark interaction in Minkowski space
using the Covariant Spectator Theory. We show that with an equal-weighted
scalar-pseudoscalar structure for the confining part of our interaction kernel
the axial-vector Ward-Takahashi identity is preserved and our model complies
with the Adler-zero constraint for pi-pi-scattering imposed by chiral symmetry.Comment: 4 pages, 2 figures; 21st International Conference on Few-Body
Problems in Physics, May 18 - 22, 2015, Chicago, US
- …