arXiv subjects

O. Ivanov

Publications and source records attributed to O. Ivanov.

26 records · Page 2Linked to original sources

arXiv2008

Transversity and T-odd PDFs from Drell-Yan processes with $pp$, $pD$ and $DD$ collisions

We estimate the single-spin asymmetries (SSA) which provide the access to transversity as well as to Boer-Mulders and Sivers PDFs via investigation of the single-polarized Drell-Yan (DY) processes with $ pp$, $pD$ and $DD$ collisions available to RHIC, NICA, COMPASS, and J-PARC. The feasibility of these SSA is studied with the new generator of polarized DY events. The performed estimations demonstrate that there exist the such kinematical regions where SSA are presumably measurable. The most useful for PDFs extraction are the limiting kinematical ranges, where one can neglect the sea PDFs contributions which occur at large values of Bjorken x. It is of interest that on the contrary to the Sivers PDF, the transversity PDF is presumably accessible only in the especial kinematical region. On the contrary to the option with the symmetric collider mode (RHIC, NICA), this is of importance for the COMPASS experiment and the future J-PARC facility where the fixed target mode is available.

hep-ph↗

arXiv2008

Shape Isomerism at N = 40: Discovery of a Proton Intruder in 67Co

The nuclear structure of 67Co has been investigated through 67Fe beta-decay. The 67Fe isotopes were produced at the LISOL facility in proton-induced fission of 238U and selected using resonant laser ionization combined with mass separation. The application of a new correlation technique unambiguously revealed a 496(33) ms isomeric state in 67Co at an unexpected low energy of 492 keV. A 67Co level scheme has been deduced. Proposed spin and parities suggest a spherical (7/2-) 67Co ground state and a deformed first excited (1/2-) state at 492 keV, interpreted as a proton 1p-2h prolate intruder state.

nucl-ex↗

arXiv2007

On duality of Drell-Yan and J/psi production processes

It is studied the model on J/psi production allowing to extract parton distribution functions (PDFs) from the combined analysis with both data on Drell-Yan and J/psi production processes. It is shown that this, so attractive from theoretical point of view, model, can be safely used in the low energy region E<100 GeV. The significance of gluon contributions to the J/psi cross-sections is investigated. The obtained results in the high energy region occur to be rather surprising.

hep-ph↗

arXiv2007

Photoinduced electrification of solids. III. Temperature dependences

Two preceding parts of a paper (cond-mat/0508457, cond-mat/0508460) considered the heuristic values of recent experiments pointing to the nearly universal occurrence of photovoltages across solid surfaces under short-circuit conditions. These voltages arise by virtue of a variety of spectrally-dependent mechanisms activated by incident photons. For the visible range, the photovoltages are obliged to the photodetachment of ions which leave the surface charged. In an attempt to learn more, we now study short-circuit photovoltages in well-defined materials including high-Tc superconductors within a broad temperature range down to liquid nitrogen. We believe our data provide a new insight into the process.

cond-mat.mtrl-sci↗

arXiv2005

Transversity and its accompanying T-odd distribution from Drell-Yan processes with pion-proton collisions

It is studied the possibility of direct extraction of the transversity and its accompanying T-odd parton distribution function (PDF) from Drell-Yan (DY) processes with unpolarized pion beam and with both unpolarized and transversely polarized proton targets. At present, such a measurement can be performed on the COMPASS experiment at CERN. The preliminary estimations performed for COMPASS kinematic region demonstrate that it is quite real to extract both transversity and its accompanying T-odd PDF in the COMPASS conditions

hep-ph↗

arXiv2005

Photoinduced electrification of solids: I. Plausible mechanisms

Experiments carried out at our laboratories have led to observing a new type of electrification, now called surface photocharging. For a consistent description, we are weighing carefully the experimental evidence against the common knowledge of frictional electrification and analyze it on the premise that photocharging may be the electric face of the structural damage produced at the surface by photodesorption or laser sputtering. We find the emerging picture well consistent and elaborate photocharging mechanisms based on familiar photodesorption steps. The first mechanism based on negative-U operates in the visible and near infrared. It involves photoelectron capture by negative-U metal sites at surface dangling bonds and photohole capture by negative-U sites at active bonds. Dihole formation leading to bond breaking is the likely prerequisite of metal ion desorption. Alternatively, unihole capture at trapped electron sites can give rise to self-trapped excitons (STE) which decay leading to surface defects formation, the prerequisite of metalloid ion desorption. As a result of the coupling to normally polarized modes, surface metal or metalloid ions are desorbed while complementary ionic charges appear in the subsurface region. Alternative photoelectrification mechanisms, such as the photostimulated migration or reorientation of surface molecule ions operating in the far infrared are also discussed. Implications for the practical use of the phenomenon are also mentioned.

cond-mat.mtrl-sci↗

arXiv2005

Photoinduced electrification of solids: II. Photovoltage transients

In relevance to the photoelectrification mechanisms proposed in Part I, we derive rate equations for the negative-u and STE photoelectrification modes and solve them under conditions close to experimental ones. Exact solutions are obtained for the case of a slow electron-hole recombination at negative-U sites. These solutions are compared with photovoltage versus time transients by "short circuit currents" in photocharging experiments.

cond-mat.mtrl-sci↗

arXiv2004

First Results on In-Beam gamma Spectroscopy of Neutron-Rich Na and Mg Isotopes at REX-ISOLDE

After the successful commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE - first physics experiments using these beams were performed. Initial experiments focused on the region of deformation in the vicinity of the neutron-rich Na and Mg isotopes. Preliminary results show the high potential and physics opportunities offered by the exotic isotope accelerator REX in conjunction with the modern Germanium gamma spectrometer MINIBALL.

nucl-ex↗