A5047854275- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Nuclear Physics and Applications
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Geophysics and Gravity Measurements
- Historical Geography and Cartography
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Hydraulic Fracturing and Reservoir Analysis
- Muon and positron interactions and applications
- Particle Accelerators and Free-Electron Lasers
- Enhanced Oil Recovery Techniques
- Reservoir Engineering and Simulation Methods
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Advanced Frequency and Time Standards
- Pulsars and Gravitational Waves Research
- Cold Atom Physics and Bose-Einstein Condensates
- Geographic Information Systems Studies
- Regional Socio-Economic Development Trends
Siberian Scientific Research Institute of Oil Industry
2024
Petersburg Nuclear Physics Institute
2008-2021
Kurchatov Institute
2015-2021
Russian Academy of Sciences
2000-2010
University of Alberta
1998-2000
Argonne National Laboratory
1999
Single-spin asymmetries for semi-inclusive electroproduction of charged pions in deep-inelastic scattering positrons are measured the first time with transverse target polarization. The asymmetry depends on azimuthal angles both pion ($\ensuremath{\phi}$) and spin axis (${\ensuremath{\phi}}_{S}$) about virtual-photon direction relative to lepton plane. extracted Fourier component $\mathbf{⟨}\mathrm{sin}(\ensuremath{\phi}+{\ensuremath{\phi}}_{S}){\mathbf{⟩}}_{UT}^{\ensuremath{\pi}}$ is a...
Precise measurements of the spin structure functions proton ${g}_{1}^{p}(x,{Q}^{2})$ and deuteron ${g}_{1}^{d}(x,{Q}^{2})$ are presented over kinematic range $0.0041\ensuremath{\le}x\ensuremath{\le}0.9$ $0.18\text{ }\text{ }{\mathrm{GeV}}^{2}\ensuremath{\le}{Q}^{2}\ensuremath{\le}20\text{ }{\mathrm{GeV}}^{2}$. The data were collected at HERMES experiment DESY, in deep-inelastic scattering 27.6 GeV longitudinally polarized positrons off hydrogen deuterium gas targets internal to HERA storage...
The HERMES experiment is collecting data on inclusive and semi-inclusive deep inelastic scattering of polarised positrons from targets H, D, 3He. These give information the spin structure nucleon. This paper describes forward angle spectrometer built for this purpose. includes numerous tracking chambers (micro-strip gas chambers, drift proportional chambers) in front behind a 1.3 T.m magnetic field, as well an extensive set detectors particle identification (a lead-glass calorimeter,...
The beam-spin asymmetry in hard electroproduction of photons has been measured. data have accumulated by the HERMES experiment at DESY using HERA 27.6 GeV longitudinally polarized positron beam and an unpolarized hydrogen-gas target. azimuthal distribution produced angle $\ensuremath{\varphi}$ relative to lepton scattering plane was determined with respect helicity state incoming beam. analyzing power $\mathrm{sin}\ensuremath{\varphi}$ moment measured be...
Results are reported from the HERMES experiment at HERA on a measurement of neutron spin structure function $g_1^n(x,Q^2)$ in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident $^3$He internal gas target. The data cover kinematic range $0.023
Single-spin asymmetries for semi-inclusive pion production in deep-inelastic scattering have been measured the first time. A significant target-spin asymmetry of distribution azimuthal angle straight phi relative to lepton plane was formed pi(+) electroproduction on a longitudinally polarized hydrogen target. The corresponding analyzing power sinstraight moment cross section is 0.022+/-0.005+/-0.003. This result can be interpreted as effect terms involving chiral-odd spin functions...
Polarized deep-inelastic scattering data on longitudinally polarized hydrogen and deuterium targets have been used to determine double-spin asymmetries of cross sections. Inclusive semi-inclusive for the production positive negative pions from were obtained in a reanalysis previously published data. kaons measured target. The separate helicity densities up down quarks anti-up, anti-down, strange sea computed these “leading order” QCD analysis. polarization up-quark is that down-quark...
Multiplicities in semi-inclusive deep-inelastic scattering are presented for each charge state of ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ and ${\mathrm{K}}^{\ifmmode\pm\else\textpm\fi{}}$ mesons. The data were collected by the HERMES experiment at HERA storage ring using 27.6 GeV electron positron beams incident on a hydrogen or deuterium gas target. results as function kinematic quantities ${x}_{\mathrm{B}}$, ${Q}^{2}$, $z$, ${P}_{h\ensuremath{\perp}}$. They represent unique set...
The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R_{2γ}, direct measure contribution hard two-photon exchange section. In measurement, 2.01 GeV electron and positron beams were directed through hydrogen gas target internal DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers time-of-flight scintillators detected elastically scattered leptons in coincidence recoiling...
The flavor asymmetry of the light quark sea nucleon is determined in kinematic range $0.02<x<0.3$ and $1<{Q}^{2}<10{\mathrm{GeV}}^{2}$ for first time from semi-inclusive deep-inelastic scattering. quantity $[\overline{d}(x)\ensuremath{-}\overline{u}(x)]/[u(x)\ensuremath{-}d(x)]$ derived a relationship between yields positive negative pions unpolarized hydrogen deuterium targets. $\overline{d}\ensuremath{-}\overline{u}$ found to be nonzero $x$ dependent, showing an excess $\overline{d}$ over...
A single-spin asymmetry in the azimuthal distribution of neutral pions relative to lepton scattering plane has been measured for first time deep-inelastic positrons off longitudinally polarized protons. The analyzing power sinφ moment cross section is 0.019±0.007(stat)±0.003(syst). This result compared asymmetries charged pion production same kinematic range. π0 size as π+ and shows a similar dependence on relevant variables. described by phenomenological calculation based fragmentation...
The momentum and helicity density distributions of the strange quark sea in nucleon are obtained leading order from charged-kaon production deep-inelastic scattering on deuteron. extracted spin-averaged K+/- multiplicities, inclusive double-spin asymmetries for polarized positrons by a deuterium target. shape distribution is softer than that average ubar dbar quarks. In region measurement 0.02 < x 0.6 Q^2 > 1.0 GeV^2, zero within experimental uncertainties.
We present a measurement of the longitudinal spin asymmetry A(||) in photoproduction pairs hadrons with high transverse momentum p(T). Data were accumulated by HERMES experiment using 27.5 GeV polarized positron beam and hydrogen target internal to HERA storage ring. For h(+)h(-) p(h(1))(T)>1.5 GeV/c p(h(2))(T)>1.0 GeV/c, measured is = -0. 28+/-0.12(stat)+/-0.02(syst). This negative value contrast positive asymmetries typically deep inelastic scattering from protons, interpreted arise gluon...
Double-spin asymmetries of semiinclusive cross sections for the production identified pions and kaons have been measured in deep inelastic scattering polarized positrons on a deuterium target. Five helicity distributions including those three sea quark flavors were extracted from these data together with reanalyzed previous hydrogen These are consistent zero all flavors. A recently predicted flavor asymmetry polarization light appears to be disfavored by data.
Single-spin asymmetries have been measured for semi-inclusive electroproduction of $\pi^+$, $\pi^-$, $\pi^0$ and $K^+$ mesons in deep-inelastic scattering off a longitudinally polarised deuterium target. The appear the distribution hadrons azimuthal angle $\phi$ around virtual photon direction, relative to lepton plane. corresponding analysing powers $\sin \phi$ moment cross section are $0.012 \pm 0.002 {(stat.)} {(syst.)}$ $0.006 0.003 $0.021 0.005 $0.013 0.006 $K^+$. 2\phi$ moments...
The first observation of an azimuthal cross section asymmetry with respect to the charge incoming lepton beam is reported from a study hard exclusive electroproduction real photons. data have been accumulated by HERMES experiment at DESY, in which HERA 27.6 GeV electron or positron scattered off unpolarized hydrogen gas target. observed attributed interference between Bethe-Heitler process and deeply virtual Compton scattering (DVCS) process. term sensitive DVCS amplitudes, provide most...
The Hermes experiment has investigated the tensor spin structure of deuteron using $27.6\text{ }\text{ }\mathrm{GeV}/c$ positron beam DESY HERA. use a tensor-polarized gas target with only negligible residual vector polarization enabled first measurement asymmetry ${A}_{zz}^{d}$ and function ${b}_{1}^{d}$ for average values Bjorken variable $0.01<⟨x⟩<0.45$ negative squared four-momentum transfer $0.5\text{ }{\mathrm{GeV}}^{2}<⟨{Q}^{2}⟩<5\text{ }{\mathrm{GeV}}^{2}$. quantities are...
Polarisation asymmetries are measured for the hard exclusive leptoproduction of real photons from a longitudinally polarised hydrogen target. These arise deeply virtual Compton scattering and Bethe-Heitler processes. From data extracted two in azimuthal distribution produced about direction exchanged photon: $$ {\mathcal{A}_{\text{UL}}} with respect to target polarisation {\mathcal{A}_{\text{LL}}} product beam polarisations. Results both compared predictions generalised parton model. The sin...
A measurement of the beam-spin asymmetry in azimuthal distribution pions produced semi-inclusive deep-inelastic scattering off protons is presented. The was performed using {HERMES} spectrometer with a hydrogen gas target and longitudinally polarized 27.6 GeV positron beam HERA. sinusoidal amplitude dependence on angle $\phi$ hadron production plane around virtual photon direction relative to lepton measured for $\pi^+,\pi^-$ $\pi^0$ mesons. this Bjorken scaling variable pion fractional...