A5100635390- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Nuclear physics research studies
- Planetary Science and Exploration
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Particle Accelerators and Free-Electron Lasers
- Astro and Planetary Science
- Advanced NMR Techniques and Applications
- Space Exploration and Technology
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Synthesis and Reactivity of Sulfur-Containing Compounds
- Cold Atom Physics and Bose-Einstein Condensates
- Muon and positron interactions and applications
- Medical Imaging Techniques and Applications
- Inorganic and Organometallic Chemistry
- Synthesis of heterocyclic compounds
- Quantum, superfluid, helium dynamics
- Asymmetric Synthesis and Catalysis
- Bluetooth and Wireless Communication Technologies
- Coordination Chemistry and Organometallics
Chiba Institute of Technology
2024
Yamagata University Hospital
2003-2024
Yamagata University
2007-2024
Ruhr University Bochum
2024
A. Alikhanyan National Laboratory
2023
Duquesne University
2023
University of Aveiro
2021-2023
The University of Tokyo
2020
Sapienza University of Rome
2019
GSI Helmholtz Centre for Heavy Ion Research
2019
First measurements of the Collins and Sivers asymmetries charged hadrons produced in deep-inelastic scattering muons on a transversely polarized 6-LiD target are presented. The data were taken 2002 with COMPASS spectrometer using muon beam CERN SPS at 160 GeV/c. asymmetry turns out to be compatible zero, as does measured within present statistical errors.
We have measured the spin-dependent structure function g1p in inclusive deep-inelastic scattering of polarized muons off protons, kinematic range 0.003<x<0.7 and 1GeV2<Q2<60GeV2. A next-to-leading order QCD analysis is used to evolve g1p(x,Q2) a fixed Q02. The first moment at Q02=10GeV2 Γ1p=0.136±0.013 (stat) ±0.009 (syst) ±0.005 (evol). This result below prediction Ellis-Jaffe sum rule by more than two standard deviations. singlet axial charge a0 found be 0.28±0.16. In Adler-Bardeen...
The differential cross sections for inclusive neutral pions as a function of transverse and longitudinal momentum in the very forward rapidity region have been measured at Large Hadron Collider (LHC) with detector (LHCf) proton-proton collisions $\sqrt{s}=$ 2.76 7 TeV proton-lead nucleon-nucleon center-of-mass energies $\sqrt{s_\text{NN}}=$ 5.02 TeV. Such are compatible hypotheses limiting fragmentation Feynman scaling. Comparing collisions, we find sizable suppression production after...
We present a determination of the gluon polarization Delta G/G in nucleon, based on helicity asymmetry quasi-real photoproduction events, Q^2<1(GeV/c)^2, with pair large transverse-momentum hadrons final state. The data were obtained by COMPASS experiment at CERN using 160 GeV polarized muon beam scattered 6-LiD target. for selected events is = 0.002 +- 0.019(stat.) 0.003(syst.). From this value, we obtain leading-order QCD analysis G/G=0.024 0.089(stat.) 0.057(syst.) x_g 0.095 and mu^2...
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...
We present a new measurement of the spin-dependent structure function g1d deuteron from deep inelastic scattering 190 GeV polarized muons on deuterons. The results are combined with our previous measurements g1d. A perturbative QCD evolution in next-to-leading order is used to compute g1d(x) at constant Q2. At Q2 = 10 GeV2, we obtain first moment Γ1d=∫1dg1ddx=0.041±0.008, flavour-singlet axial charge nucleon a0 0.30 ± 0.08, and an strange quark as −0.09 0.03. Using earlier determination Γ1p,...
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....
We present a new measurement of the virtual photon proton asymmetry A1p from deep inelastic scattering polarized muons on protons in kinematic range 0.0008 < x 0.7 and 0.2 Q2 100 GeV2. With this, statistical uncertainty our has improved by factor 2 compared to previous measurements. The spin-dependent structure function g1p is determined for data with > 1 A perturbative QCD evolution next-to-leading order used determine g1p(x) at constant Q2. At = 10 GeV2 we find, measured range,...
In this paper, we report the production cross-section of forward photons in pseudorapidity regions $\eta\,>\,10.94$ and $8.99\,>\,\eta\,>\,8.81$, measured by LHCf experiment with proton--proton collisions at $\sqrt{s}$ = 13 TeV. The results from analysis 0.191 $\mathrm{nb^{-1}}$ data obtained June 2015 are compared to predictions several hadronic interaction models that used air-shower simulations for ultra-high-energy cosmic rays. Although none agree perfectly data, EPOS-LHC shows best...
We have searched for exclusive production of exotic charmonia in the reaction $\mu^+~N \rightarrow \mu^+ (J\!/\!\psi\pi^+\pi^-)\pi^{\pm}~N'$ using COMPASS data collected with incoming muons 160 GeV/$c$ and 200 momentum. In $J\!/\!\psi\pi^+\pi^-$ mass distribution we observe a signal statistical significance 4.1 $\sigma$. Its width are consistent those $X(3872)$. The shape $\pi^+\pi^-$ from observed decay into shows disagreement previous observations may be interpreted as possible evidence...
Exclusive production of ρ0 mesons was studied at the COMPASS experiment by scattering 160GeV/c muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured as a function Q2, xBj, or pT2. The sinϕS asymmetry is found to be −0.019±0.008(stat.)±0.003(syst.). All other are also small magnitude consistent with zero within experimental uncertainties. Very recent calculations using GPD-based model agree well present results. data interpreted...
Azimuthal asymmetries in semi-inclusive production of positive (h^+) and negative hadrons (h^-) have been measured by scattering 160 GeV muons off longitudinally polarised deuterons at CERN. The were decomposed several terms according to their expected modulation the azimuthal angle phi outgoing hadron. Each term receives contributions from one or spin transverse-momentum-dependent parton distribution fragmentation functions. amplitudes all phi-modulation hadron integrated over kinematic...
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...
The longitudinal polarisation transfer from muons to lambda and anti-lambda hyperons, D_LL, has been studied in deep inelastic scattering off an unpolarised isoscalar target at the COMPASS experiment CERN. spin transfers produced current fragmentation region exhibit different behaviours as a function of x xF . measured dependences D^lambda_LL are compatible with zero, while D^anti-lambda_LL tends increase xF, reaching values 0.4 - 0.5. resulting average = -0.012 +- 0.047 0.024 0.249 0.056...
The Large Hadron Collider forward (LHCf) experiment was motivated to understand the hadronic interaction processes relevant cosmic-ray air shower development. We have developed radiation-hard detectors with use of Gd2SiO5 (GSO) scintillators for proton-proton √s = 13 TeV collisions. Calibration such photon measurement has been completed at CERN SPS T2-H4 line in 2015 using electron beams 100–250 GeV and muon 150–250 . After channel-by-channel absolute energy calibration, resolution...
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...
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....
Exclusive production of the isoscalar vector mesons $\omega$ and $\phi$ is measured with a 190 GeV$/c$ proton beam impinging on liquid hydrogen target. Cross section ratios are determined in three intervals Feynman variable $x_{F}$ fast proton. A significant violation OZI rule found, confirming earlier findings. Its kinematic dependence invariant mass $M_{p\mathrm{V}}$ system formed by $p_\mathrm{fast}$ meson $V$ discussed terms diffractive $p_\mathrm{fast}V$ resonances competition central...
A 2.5 m long liquid hydrogen target has been developed for the COMPASS experiment at CERN to investigate nucleon spin structure via Deeply Virtual Compton Scattering (DVCS) process.To recognize exclusive DVCS events, produced photons and slow protons need be detected.In order do so, material budget around minimal.A 0.125 mm thick Kapton s cell a 1 carbon fiber vacuum chamber with Mylar window have constructed tested.Finally, system was successfully employed during pilot run in end of...
We have developed an event mixing technique to observe Bose-Einstein correlations (BEC) between two identical neutral pions produced in photo-induced reactions the non-perturbative QCD energy region.It is found that missing-mass consistency cut and pion-energy are essential for method effectively extract BEC observables.A Monte Carlo (MC) simulation used validate these constraints confirms efficiency of this method.Our work paves way similar studies at lower energies where multiplicity...