M. Hoffmann
A5012653115- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle physics theoretical and experimental studies
- Quantum, superfluid, helium dynamics
- Random Matrices and Applications
- Nuclear physics research studies
- Chemical Synthesis and Characterization
- Inorganic and Organometallic Chemistry
- Organophosphorus compounds synthesis
- Atomic and Subatomic Physics Research
University of Bonn
1875-2024
A. Alikhanyan National Laboratory
2023
University of Aveiro
2021
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...
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....
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...
Based on the observation of sizeable target-transverse-spin asymmetries in single-hadron and hadron-pair production Semi-Inclusive measurements Deep Inelastic Scattering (SIDIS), chiral-odd transversity quark distribution functions $h_1^q$ are nowadays well established. Several possible channels to access these were originally proposed. One candidate is measurement polarisation $\Lambda$ hyperons produced SIDIS off transversely polarised nucleons, where transverse struck might be transferred...
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>...
New results are presented on a high-statistics measurement of Collins and Sivers asymmetries charged hadrons produced in deep inelastic scattering muons transversely polarised $^6$LiD target. The data were taken 2022 with the COMPASS spectrometer using 160 \gevv\ muon beam at CERN, 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 distribution...
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 COMPASS Collaboration performed measurements of the Drell-Yan process in 2015 and 2018 using a 190 GeV/c $\pi^{-}$ beam impinging on transversely polarised ammonia target. Combining data both years, we present final results amplitudes five azimuthal modulations dimuon production cross section. Three these transverse-spin-dependent asymmetries (TSAs) probe nucleon leading-twist Sivers, transversity, pretzelosity transverse-momentum dependent (TMD) parton distribution functions (PDFs)....
We present the study of production double $J/ψ$ mesons using COMPASS data collected with a 190 GeV/$c$ $π^-$ beam scattering off NH$_{3}$, Al and W targets. Kinematic distributions events are analysed, cross section is estimated for each The results compared to predictions from single- double-parton models as well pion intrinsic charm tetraquark exotic resonance hypotheses. It demonstrated that single parton mechanism gives dominant contribution sufficient describe data. An upper limit on...