A5034968605- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Nuclear physics research studies
- High-Energy Particle Collisions Research
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Testicular diseases and treatments
- COVID-19 epidemiological studies
- Gastric Cancer Management and Outcomes
- Advanced Condensed Matter Physics
- Solid-state spectroscopy and crystallography
- Osteoarthritis Treatment and Mechanisms
- Orthopaedic implants and arthroplasty
- Particle Accelerators and Free-Electron Lasers
- Colorectal Cancer Surgical Treatments
- Total Knee Arthroplasty Outcomes
- Hepatitis Viruses Studies and Epidemiology
- Sexual Differentiation and Disorders
- Sarcoma Diagnosis and Treatment
- Scientific Research and Discoveries
- Travel-related health issues
- Random Matrices and Applications
- Quantum and electron transport phenomena
University of Bonn
2014-2024
A. Alikhanyan National Laboratory
2023
University of Aveiro
2023
Åland University of Applied Sciences
2022
Klinikum Weiden
2014-2017
University of Giessen
2013-2015
Orthopädische Universitätsklinik
2003
The first measurement of the helicity dependence photoproduction cross section single neutral pions off protons is reported for photon energies from 600 to 2300 MeV, covering nearly full solid angle. data are compared predictions SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between observed, which traced in amplitudes well-known established resonances. Precise values several resonances reported.
The excitation function and momentum distribution of ${\ensuremath{\eta}}^{\ensuremath{'}}$ mesons have been measured in photoproduction off $^{93}\mathrm{Nb}$ the energy range 1.2--2.9 GeV. experiment has performed with combined Crystal Barrel MiniTAPS detector system, using tagged photon beams from ELSA electron accelerator. Information on sign magnitude real part ${\ensuremath{\eta}}^{\ensuremath{'}}$-Nb potential extracted a comparison data model calculations. An attractive...
New data on the polarization observables $T$, $P$, and $H$ for reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{0}$ are reported. The results extracted from azimuthal asymmetries when a transversely polarized butanol target linearly photon beam used. were taken at Bonn electron stretcher accelerator ELSA using CBELSA/TAPS detector. These earlier used to perform truncated energy-independent partial wave analysis in sliced-energy bins. This is compared...
Data on the polarization observables T, P, and H for reaction $\gamma p\to p\pi^0$ are reported. Compared to earlier data from other experiments, our more precise extend covered range in energy angle substantially. The results were extracted azimuthal asymmetries measured using a transversely polarized target linearly photons. taken at Bonn electron stretcher accelerator ELSA with CBELSA/TAPS detector. Within Bonn-Gatchina partial wave analysis, new lead significant narrowing of error band...
The polarization observables T,E,P,H, and G in photoproduction of η mesons off protons are measured for photon energies from threshold to W=2400 MeV (T), 2280 (E), 1620 (P,H), or 1820 (G), covering nearly the full solid angle. data compared predictions SAID, MAID, JüBo, BnGa partial-wave analyses. A refit within approach including further yields precise branching ratios Nη decay nucleon resonances. Nη-branching ratio 0.33±0.04 N(1650)1/2− is found, which reduces large controversially...
The production of vector mesons in deep inelastic scattering is an interesting yet scarsely explored channel to study the transverse spin structure nucleon and related phenomena. COMPASS collaboration has performed first measurement Collins Sivers asymmetries for inclusively produced $\rho^0$ mesons. analysis based on data set collected $2010$ using a $160\,\,\rm{GeV}/c$ $\mu^+$ beam impinging transversely polarized $\rm{NH}_3$ target. $\rho^{0}$ are selected from oppositely charged hadron...
In a search for $\omega$ mesic states, the production of $\omega$-mesons in coincidence with forward going protons has been studied photon induced reactions on $^{12}$C incident energies 1250 - 3100 MeV. The $\pi^0 \gamma$ pairs from decays bound or quasi-free have measured CBELSA/TAPS detector system registered MiniTAPS array. Structures total energy distribution pairs, which would indicate population and decay $\omega~^{11}$B are not observed. cross section 0.3 nb/MeV/sr observed state...
Data on the beam asymmetry $\Sigma$ in photoproduction of $\eta$ mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range $W=$ 1748 2045 MeV). The data cover full solid angle that allows a precise moment analysis. For first time, strong cusp effect polarization observable has been observed is an branch-point singularity at $p\eta'$ threshold [$E_\gamma=$ 1447 ($W=$ 1896 MeV)]. latest BnGa partial wave analysis includes new and yields indication...
New results are presented on a high-statistics measurement of Collins and Sivers asymmetries charged hadrons produced in deep inelastic scattering muons transversely polarized ^{6}LiD target. The data were taken 2022 with the COMPASS spectrometer using 160 GeV muon beam at CERN, statistically balancing existing proton targets. first from about two-thirds new have total uncertainties smaller by up to factor three compared previous deuteron measurements. Using all results, both transversity...
The first measurements of the beam-target-helicity-asymmetries $E$ and $G$ in photoproduction $\omega$-mesons off protons at CBELSA/TAPS experiment are reported. ($G$) was measured using circularly (linearly) polarised photons a longitudinally target. over photon energy range from close to threshold ($E_\gamma = 1108$~MeV) $E_\gamma 2300$~MeV single interval $1108 < E_\gamma <1300$~MeV. Both cover full solid angle. observables highly sensitive contribution baryon resonances, with acting as...
A set of measurements azimuthal asymmetries in the production pairs identified hadrons deep-inelastic scattering muons on transversely polarised 6LiD (deuteron) and NH3 (proton) targets is presented. All available data collected years 2003–2004 2007/2010 with COMPASS spectrometer using a muon beam 160GeV/c at CERN SPS were analysed. The provide access to transversity distribution functions via fragmentation function that principle may be independently obtained from e+e− annihilation data....
<b><i>Purpose:</i></b> The aim of this study was to evaluate the quality care and interdisciplinary cooperation in palliative treatment colorectal cancer (CRC), including associated costs. <b><i>Patients Methods:</i></b> 103 patients were enrolled from 13 institutions reflect existing clinical reality costs CRC treatment. We present outcome compare results obtained 3 centers with double-figure recruitment numbers (centers A, B, C)....
Studienziel: Ziel der prospektiv randomisierten Therapievergleichsstudie war es, die Frage nach Notwendigkeit des Patellarückflächenersatzes bei Patienten mit einer primären Gonarthrose ohne wesentliche retropatellare Schmerzsymptomatik zu klären. Methode: Von Mai 1999 bis 2000 wurden insgesamt 50 in randomisierte aufgenommen. Sämtliche Oberflächenersatzprothesen gleichen Typs (n = 25) und Patellarückflächenersatz versorgt. Einschlusskriterien waren, dass Vorliegen Patellaverschiebeschmerz...
A measurement of the double-polarization observable
Abstract We report on a measurement of Spin Density Matrix Elements (SDMEs) in hard exclusive $$\rho ^0$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mi>ρ</mml:mi> <mml:mn>0</mml:mn> </mml:msup> </mml:math> meson muoproduction at COMPASS using 160 GeV/ c polarised $$ \mu ^{+}$$ <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> and ^{-}$$ <mml:mo>-</mml:mo> beams impinging liquid hydrogen target. The covers the kinematic range 5.0 $$c^2$$ <mml:mi>c</mml:mi>...
The COMPASS Collaboration performed measurements of the Drell-Yan process in 2015 and 2018 using a 190 GeV/c π^{-} beam impinging on transversely polarized ammonia target. Combining data both years, we present final results amplitudes five azimuthal modulations, which correspond to transverse-spin-dependent asymmetries (TSAs) dimuon production cross section. Three them probe nucleon leading-twist Sivers, transversity, pretzelosity transverse-momentum dependent (TMD) parton distribution...
The multiplicities of positive and negative pions, kaons unidentified hadrons produced in deep-inelastic scattering are measured bins the Bjorken scaling variable $x$, relative virtual-photon energy $y$ fraction transferred to final-state hadron $z$. Data were obtained by COMPASS Collaboration using a 160 GeV muon beam both electric charges liquid hydrogen target. These measurements cover kinematic domain with photon virtuality $Q^2 > 1$ (GeV/$c)^2$, $0.004 < x 0.4$, $0.1 y 0.7$ $0.2 z...
A new and detailed measurement of the cross section for hard exclusive neutral-pion muoproduction on proton was performed in a wide kinematic region, with photon virtuality $Q^2$ ranging from 1 to 8 (GeV/$c$)$^{\rm\, 2}$ Bjorken variable $x_{\rm Bj}$ 0.02 0.45. The data were collected at COMPASS CERN using 160 GeV/$c$ longitudinally polarised $\mu^+$ $\mu^-$ beams scattering off 2.5 m long liquid hydrogen target. From average measured sections, virtual-photon--proton is determined as...