A. Austregesilo
A5005516475- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Nuclear physics research studies
- Dark Matter and Cosmic Phenomena
- CCD and CMOS Imaging Sensors
- International Science and Diplomacy
- Medical Imaging Techniques and Applications
- Advanced Graph Theory Research
- Atomic and Molecular Physics
- Graph Labeling and Dimension Problems
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Photonic and Optical Devices
- Quantum Mechanics and Applications
- Advanced NMR Techniques and Applications
- Black Holes and Theoretical Physics
- Algebraic and Geometric Analysis
- Astro and Planetary Science
- Advancements in Photolithography Techniques
- Scientific Computing and Data Management
- Computational Physics and Python Applications
Thomas Jefferson National Accelerator Facility
2018-2025
Sesame Workshop
2024
Carnegie Mellon University
2019-2021
Technical University of Munich
2010-2020
European Organization for Nuclear Research
2009-2020
University of Aveiro
2018
Campbell Collaboration
2012-2016
We report on the measurement of γp→J/ψp cross section from E_{γ}=11.8 GeV down to threshold at 8.2 using a tagged photon beam with GlueX experiment. find that total falls toward less steeply than expected two-gluon exchange models. The differential dσ/dt has an exponential slope 1.67±0.39 GeV^{-2} 10.7 average energy. LHCb pentaquark candidates P_{c}^{+} can be produced in s channel this reaction. see no evidence for them and set model-dependent upper limits their branching fractions...
The COMPASS Collaboration at CERN has measured the transverse spin azimuthal asymmetry of charged hadrons produced in semi-inclusive deep inelastic scattering using a 160 GeV μ+ beam and transversely polarised NH3 target. Sivers proton been extracted Bjorken x range 0.003<x<0.7. new measurements have small statistical systematic uncertainties few percent confirm with considerably better accuracy previous measurement. is found to be compatible zero for negative positive hadrons, clear...
The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use CERN SPS 190 GeV/c π^{-} beam and a transversely polarized ammonia target. Three giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3 GeV/c^{2} 8.5 GeV/c^{2}. Within experimental uncertainties, observed sign Sivers asymmetry found be consistent...
New results for the double spin asymmetry A1p and proton longitudinal structure function g1p are presented. They were obtained by COMPASS Collaboration using polarised 200 GeV muons scattered off a longitudinally NH3 target. The data collected in 2011 complement those recorded 2007 at 160 GeV, particular lower values of x. improve statistical precision g1p(x) about factor two region x≲0.02. A next-to-leading order QCD fit to g1 world is performed. It leads new determination quark...
Measurements of the Collins and Sivers asymmetries for charged pions neutral kaons produced in semi-inclusive deep-inelastic scattering high energy muons off transversely polarised protons are presented. The results were obtained using all available COMPASS proton data, which taken years 2007 2010. exhibit valence region a non-zero signal there hints also kaons. found to be positive compatible with zero otherwise.
We report the total and differential cross sections for $J/\psi$ photoproduction with large acceptance GlueX spectrometer photon beam energies from threshold at 8.2~GeV up to 11.44~GeV over full kinematic range of momentum transfer squared, $t$. Such coverage facilitates extrapolation forward ($t = 0$) point beyond physical region. The section is used by many theoretical models plays an important role in understanding its relation $J/\psi-$proton interaction. These measurements near are also...
First measurements of azimuthal asymmetries in hadron-pair production deep-inelastic scattering muons on transversely polarised ^6LiD (deuteron) and NH_3 (proton) targets are presented. The data were taken the years 2002-2004 2007 with COMPASS spectrometer using a muon beam 160 GeV/c at CERN SPS. provide access to transversity distribution functions, without involving Collins effect as single hadron production. sizeable measured NH_ target indicate non-vanishing u-quark two-hadron...
Spin-averaged asymmetries in the azimuthal distributions of positive and negative hadrons produced deep inelastic scattering were measured using CERN SPS muon beam at $160$ GeV/c a $^6$LiD target. The amplitudes three modulations $\cos\phi_h$, $\cos2\phi_h$ $\sin\phi_h$ obtained binning data separately each relevant kinematic variables $x$, $z$ or $p_T^{\,h}$ three-dimensional grid these variables. $\cos \phi_h$ 2\phi_h$ show strong dependencies both for hadrons.
The main characteristics of the COMPASS experimental setup for physics with hadron beams are described. This was designed to perform exclusive measurements processes several charged and/or neutral particles in final state. Making use a large part apparatus that previously built spin structure studies muon beam, it also features new target system as well or upgraded detectors. is able operate at high incident flux available CERN. It characterised by angular and momentum coverages, nearly flat...
A measurement of the azimuthal asymmetry in dihadron production deep-inelastic scattering muons on transversely polarised proton (NH$_{3}$) targets are presented. They provide independent access to transversity distribution functions through Collins single hadron production. The data were taken year $2010$ with COMPASS spectrometer using a $160\,\mbox{GeV}/c$ muon beam CERN SPS, increasing by factor about three available statistics previously published $2007$. measured sizeable is good...
The COMPASS collaboration at CERN has measured diffractive dissociation of 190 GeV/$c$ pions into the $\pi^-\pi^-\pi^+$ final state using a stationary hydrogen target. A partial-wave analysis (PWA) was performed in bins $3\pi$ mass and four-momentum transfer isobar model so far largest PWA consisting 88 waves. narrow $J^{PC} = 1^{++}$ signal is observed $f_0(980)\,\pi$ channel. We present resonance-model study subset spin-density matrix selecting states with 2^{++}$ $4^{++}$ decaying...
We have performed the most comprehensive resonance-model fit of $\pi^-\pi^-\pi^+$ states using results our previously published partial-wave analysis (PWA) a large data set diffractive-dissociation events from reaction $\pi^- + p \to \pi^-\pi^-\pi^+ p_\text{recoil}$ with 190 GeV/$c$ pion beam. The PWA results, which were obtained in 100 bins three-pion mass, $0.5 < m_{3\pi} 2.5$ GeV/$c^2$, and simultaneously 11 reduced four-momentum transfer squared, $0.1 t' 1.0$ $($GeV$/c)^2$, are subjected...
Exclusive production of $\eta\pi^-$ and $\eta'\pi^-$ has been studied with a $191\,\textrm{GeV}/c$ $\pi^-$ beam impinging on hydrogen target at COMPASS (CERN). Partial-wave analyses reveal different odd/even angular momentum ($L$) characteristics in the inspected invariant mass range up to $3\,\textrm{GeV}/c^2$. A striking similarity between two systems is observed for $L=2,4,6$ intensities (scaled by kinematical factors) relative phases. The known resonances $a_2(1320)$ $a_4(2040)$ are line...
The COMPASS experiment at the CERN SPS has studied diffractive dissociation of negative pions into π−π−π+ final state using a 190 GeV/c pion beam hitting lead target. A partial wave analysis been performed on sample 420 000 events taken values squared 4-momentum transfer t′ between 0.1 and 1 GeV2/c2. well-known resonances a1(1260), a2(1320), π2(1670) are clearly observed. In addition, data show significant natural-parity exchange production resonance with spin-exotic quantum numbers JPC=1−+...
We present a LO evaluation of helicity densities valence, Δuv+Δdv, non-strange sea, Δu¯+Δd¯, and strange quarks, Δs (assumed to be equal Δs¯). They have been obtained from the inclusive asymmetry A1,d semi-inclusive asymmetries A1,dπ+, A1,dπ−, A1,dK+, A1,dK− measured in polarised deep inelastic muon–deuteron scattering. The full deuteron statistics COMPASS (years 2002–2004 2006) has used. data cover range Q2>1(GeV/c)2 0.004<x<0.3. Both are found good agreement with previous measurements....
The gluon polarisation in the nucleon was measured using open charm production by scattering 160 GeV/c polarised muons off longitudinally protons or deuterons. data were taken COMPASS collaboration between 2002 and 2007. A detailed account is given of analysis method that includes application neural networks. Several decay channels D^0 mesons are investigated. Longitudinal spin asymmetries D meson cross-sections extracted bins transverse momentum energy. At leading order QCD accuracy average...
A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered data: photon virtuality ${Q}^{2}>1\text{ }\text{ }(\mathrm{GeV}/c{)}^{2}$, invariant mass hadronic system $W>5\text{ }\mathrm{GeV}/{c}^{2}$, Bjorken scaling variable range $0.003<x<0.4$, fraction virtual energy carried $0.2<z<0.8$, and square transverse...
Proton transverse-spin azimuthal asymmetries are extracted from the COMPASS 2010 semi-inclusive hadron measurements in deep inelastic muon-nucleon scattering those four regions of photon virtuality $Q^2$, which correspond to di-muon mass $\sqrt{Q^2}$ used ongoing analysis Drell-Yan measurements. This allows for a future direct comparison nucleon transverse-momentum-dependent parton distribution functions these two alternative Various two-dimensional kinematic dependences presented induced by...
The COMPASS collaboration has collected the currently largest data set on diffractively produced ${\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$ final states using a negative pion beam of $190\text{ }\text{ }\mathrm{GeV}/c$ momentum impinging stationary proton target. This allows for systematic partial-wave analysis in 100 bins three-pion mass, $0.5<{m}_{3\ensuremath{\pi}}<2.5\text{ }\mathrm{GeV}/{c}^{2}$, and 11 reduced four-momentum...