A5015624712- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Noncommutative and Quantum Gravity Theories
- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Atomic and Subatomic Physics Research
- Quantum Electrodynamics and Casimir Effect
- Quantum Mechanics and Applications
- Advanced NMR Techniques and Applications
- Dark Matter and Cosmic Phenomena
- Muon and positron interactions and applications
- Algebraic and Geometric Analysis
- Cold Atom Physics and Bose-Einstein Condensates
- Relativity and Gravitational Theory
- Particle Detector Development and Performance
- Radiation Detection and Scintillator Technologies
- Gyrotron and Vacuum Electronics Research
- Experimental and Theoretical Physics Studies
- Neutrino Physics Research
- Advanced Optical Network Technologies
- Superconducting Materials and Applications
- Numerical methods for differential equations
- Biofield Effects and Biophysics
- International Science and Diplomacy
Universidade Federal do Triângulo Mineiro
2025
University of Genoa
2025
Istituto Nazionale di Alta Matematica Francesco Severi
2025
Universidade Federal do ABC
2023-2024
Universidade Estadual Paulista (Unesp)
2014-2022
Universidade de Santiago de Compostela
1995-2004
National Institute for Subatomic Physics
1997-2004
Universidad de Santiago de Chile
1993-2000
Direction des énergies
1994
University of Mons
1994
We present the final results of spin asymmetries A1 and structure functions g1 proton deuteron in kinematic range 0.0008<x<0.7 0.2<Q2<100GeV2. For determination A1, addition to usual method which employs inclusive scattering events includes a large radiative background at low x, we use new minimizes by selecting with least one hadron as well muon state. find that this gives smaller errors for x<0.02, so it is combined provide optimal set results.Received 18 May...
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...
We present a new measurement of the spin-dependent structure function g1d deuteron in deep inelastic scattering 190 GeV polarised muons on deuterons, kinematic range 0.003 < x 0.7 and 1 GeV2 Q2 60 GeV2. This is found to be negative at small x. The first moment Γ1d=∫01g1ddx evaluated Q02 = 10 0.034 ± 0.009 (stat.) 0.006 (syst.). value below Ellis-Jaffe sum rule prediction by three standard deviations. Using our earlier determination Γ1p, we obtain Γ1p − Γ1n 0.199 0.038 which agrees with Bjorken rule.
We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering polarised muons on protons deuterons in the range 0.003<x<0.7 Q2>1 GeV2. Compared to our previous publication this subject, with new data statistical errors have been reduced by nearly factor two. From these inclusive we determine quark distributions valence quarks non-strange sea at Q2=10 The u distribution, Δuv(x), is positive polarisation increases x. d...
We present a next-to-leading order QCD analysis of the presently available data on spin structure function g1 including final from Spin Muon Collaboration. results for first moments proton, deuteron, and neutron functions, determine singlet nonsinglet parton distributions in two factorization schemes. also test Bjorken sum rule find agreement with theoretical prediction at level 10%.Received 18 May 1998DOI:https://doi.org/10.1103/PhysRevD.58.112002©1998 American Physical Society
We present a measurement of the longitudinal spin cross section asymmetry for deep-inelastic muon-nucleon interactions with two high transverse momentum hadrons in final state. Two methods event classification are used to increase contribution photon-gluon fusion process above 30%. The most effective one, based on neural network approach, provides asymmetries Al→NlhhXp=0.030±0.057(stat)±0.010(syst) and Al→NlhhXd=0.070±0.076(stat)±0.010(syst). From these values we derive an averaged gluon...
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 measured the spin asymmetry in scattering of 100 GeV longitudinally-polarized muons on transversely polarized protons. The was found to be compatible with zero kinematic range 0.006 < x 0.6, 1 Q2 30GeV2. From this result we derive upper limits for virtual photon-proton A2, and structure function g2. For 0.15, A2 is significantly smaller than its positivity limit √R.
In this work, we shall analyse the necessity of a proper definition dual structure for Elko spinors and singular in general. We examine detail why Dirac fails, it is not functional these cases, highlighting all physical consequences misdirection. The approach considered here different from one usually taken current literature. pinpoint shortcomings that brings to particle interpretation propagator structure, as well implications non-locality existence negative energy levels. This...
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,...
Mass dimension one fermionic fields are prime candidates to describe dark matter, due their intrinsic neutral nature, as they constructed eigenstates of the charge conjugation operator with dual helicity. To formulate meaning darkness, fermion-photon coupling is scrutinized a Pauli-like interaction, and path integral then formulated from phase space constraint structure. Ward-Takahashi-like identities Schwinger-Dyson equations, together renormalizability, employed investigate...
A bstract Not all complete set of spinors can be used as expansion coefficients a quantum field. In fact, Steven Weinberg established the uniqueness Dirac for this purpose provided: (a) one paid due attention to multiplicative phases each spinors, and (b) paired these creation annihilation operators in specific manner. This is implicit his implementation rotational symmetry spin half Among numerous that are available physicist, Elko occupies unique status allows it enter field without...
A muon beam polarimeter has been built for the SMC experiment at CERN SPS, energies of 100 to 200 GeV. The polarisation is determined from energy spectrum positrons decay μ+ → e+ νcνμ. − 0.82 measured with a relative systematic accuracy 3%.
Considering the recent advances, weak correlation between massive Kalb-Ramond and Proca models is investigated using a set of complementary quantum field techniques beyond semi-classical approach. A consistent framework to discuss abrupt degree freedom variation in massless limit established. In this manner, Stueckelberg procedure generalized for present case derive Ward-Takahashi constraints even case. By adding couplings with fermionic matter fields, dual broken due explicit form radiative...
In this work, we shall analyze the necessity of a proper definition dual structure for Elko spinors, and singular spinors in general. We examine detail why Dirac fails it is not functional these cases, highlighting all physical consequences misdirection. The approach considered here different from one usually taken current literature. pinpoint shortcomings that brings to particle interpretation, propagator structure, as well implications non-locality, existence negative energy levels. This...
We report a large enhancement of 1.7 in deuteron polarization up to values 0.6 due frequency modulation the polarizing microwaves two liters polarized target using method dynamic nuclear polarization. This was used during deep inelastic muon-deuteron scattering experiment at CERN. Measurements electron paramagnetic resonance absorption spectra show that gives rise additional microwave spectral wings. Although these results are not understood theoretically, they may provide useful testing...
An analytic model of the deuteron absorption function has been developed and is compared to experimental NMR signals deuterated butanol obtained at SMC experiment in order determine polarization. The includes dipolar broadening a frequency-dependent treatment intensity factors. high-precision TE signal data available are used adjust for Q-meter distortions dispersion effects. Once adjustment made, enhanced polarizations determined by asymmetry TE-calibration methods compare well within...