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Dymov, S.

Publications and source records attributed to Dymov, S..

7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97 - GeV / c Deuterons in a Storage Ring

Here, we observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10 -29 $e$ cm.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Measurement of the absolute differential cross section of proton–proton elastic scattering at small angles

The differential cross section for proton-proton elastic scattering has been measured at a beam kinetic energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12°-16° to 25°-30°, depending on the energy. A precision in the overall normalisation of typically 3% was achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon the results of a partial wave analysis. Furthermore, after extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Spin Physics at ANKE-COSY

The COSY accelerator (Jülich, Germany) provides beams of polarised protons and deuterons. The ANKE facility at COSY is equipped with polarised hydrogen and deuterium atomic gas targets. The reactions investigated with polarised probes at ANKE include the deuteron break-up at small and large momentum transfer, the pion production processes in pp and pn collisions and the near-threshold η meson production in dip d-vector p→{sup 3}Heη process. Use of the polarised deuteron beam properties allowed a precision measurement of the η meson mass. The future experimental program covers the study of the elementary pp and pn-interaction with polarised beams up to the maximal COSY energy, and a double polarised measurement of the A {sub x, z }spin correlation parameter in the pN → {pp}{sub s }π process.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Production of K⁺K⁻ pairs in proton-proton collisions below the Φ meson threshold

The pp→ppK⁺K⁻ reaction was measured below the Φ threshold at a beam energy of 2.568 GeV using the COSY-ANKE magnetic spectrometer. By assuming that the four-body phase space is distorted only by the product of two-body final-state interactions, fits to a variety of one-dimensional distributions permit the evaluation of differential and total cross sections. The shapes of the distributions in the K p and K pp invariant masses are reproduced only if the K⁻ p interaction is even stronger than that found at higher energy. The cusp effect in the K⁺K⁻ distribution at the K⁰K¯¯¯⁰ threshold is much more clear and some evidence is also found for coupling between the K⁻ p and K¯¯¯⁰n channels. However, the energy dependence of the total cross section cannot be reproduced by considering only a simple product of such pairwise final-state interactions.

Ye, Q. J.↗
DOE OSTI2012

Production of K⁺K⁻ pairs in proton-proton collisions at 2.83 GeV

Differential and total cross sections for the pp→ppK⁺K⁻ reaction have been measured at a proton beam energy of 2.83 GeV using the COSY-ANKE magnetic spectrometer. Detailed model descriptions fitted to a variety of one-dimensional distributions permit the separation of the pp→ppφ cross section from that of non-φ production. The differential spectra show that higher partial waves represent the majority of the pp→ppφ total cross section at an excess energy of 76 MeV, whose energy dependence would then seem to require some s-wave φp enhancement near threshold. The non-φ data can be described in terms of the combined effects of two-body final state interactions using the same effective scattering parameters determined from lower energy data.

Ye, Q. J.↗