Deeply virtual Compton scattering at small x

We calculate the cross section of the deeply virtual Compton scattering at large energies and intermediate momentum transfers.Comment: 26 pages, 13 postscript figures, two figures and three references adde

Effect of atomic diffusion on the Raman-Ramsey coherent population trapping resonances

We experimentally investigated the characteristics of two-photon transmission resonances in Rb vapor cells with different amounts of buffer gas under the conditions of steady-state coherent population trapping (CPT) and a pulsed Raman-Ramsey (RR) CPT interrogation scheme. We particularly focused on the influence of the Rb atoms diffusing in and out of the laser beam. We showed that this effect modifies the shape of both CPT and RR resonances as well as their projected performance for CPT clock applications. In particular we found that at moderate buffer gas pressures RR-CPT did not improve the projected atomic clock stability compared to the regular steady-state CPT resonance. (C) 2016 Optical Society of Americ

Ugra first institutuion of higher education: way from branch to university

В статье показана 25-летняя история Нижневартовского государственного университета, его достижения и проблемы. Даны результаты опросов по проблеме высшего образования.The article reveals the 25 year history of Nizhnevartovsk State University, its achievements and challenges. The polling results on the problems of education are presented

Lepidoptera (Insecta) of proposed specially protected natural area "Belokurikha nature park" (Northern Altai). First results

149 Lepidoptera species from 16 families were reported for the territory of the proposed protected area "Belokurikha Natural Park". This list is the primary data on the fauna of Lepidoptera in the region. Most of the species belongs to Euro-Siberian and Transpalaearctic groups

Scaling Tests of the Cross Section for Deeply Virtual Compton Scattering

We present the first measurements of the ep → epγ cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region. The Q2 dependence (from 1.5 to 2.3 GeV2) of the helicity-dependent cross section indicates the twist-2 dominance of DVCS, proving that generalized parton distributions (GPDs) are accessible to experiment at moderate Q2. The helicity-independent cross section is also measured at Q2=2.3 GeV2. We present the first model-independent measurement of linear combinations of GPDs and GPD integrals up to the twist-3 approximation

A precise extraction of the induced polarization in the 4He(e,e'p)3H reaction

We measured with unprecedented precision the induced polarization Py in 4He(e,e'p)3H at Q^2 = 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2. The induced polarization is indicative of reaction-mechanism effects beyond the impulse approximation. Our results are in agreement with a relativistic distorted-wave impulse approximation calculation but are over-estimated by a calculation with strong charge-exchange effects. Our data are used to constrain the strength of the spin independent charge-exchange term in the latter calculation.Comment: submitted to Physical Review Letter

Polarization Transfer in the 4He(e,e'p)3H Reaction at Q^2 = 0.8 and 1.3 (GeV/c)^2

Proton recoil polarization was measured in the quasielastic 4He(e,e'p)3H reaction at Q^2 = 0.8 (GeV/c)^2 and 1.3 (GeV/c)^2 with unprecedented precision. The polarization-transfer coefficients are found to differ from those of the 1H(e,e' p) reaction, contradicting a relativistic distorted-wave approximation, and favoring either the inclusion of medium-modified proton form factors predicted by the quark-meson coupling model or a spin-dependent charge-exchange final-state interaction. For the first time, the polarization-transfer ratio is studied as a function of the virtuality of the proton

The Proton Elastic Form Factor Ratio at Low Momentum Transfer

High precision measurements of the proton elastic form factor ratio have been made at four-momentum transfers, Q^2, between 0.2 and 0.5 GeV^2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q^2 range the deviation from unity is primarily due to GEp being smaller than the dipole parameterization.Comment: 5 pages, 2 figure