A5100767580- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Quantum Chromodynamics and Particle Interactions
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Computational Physics and Python Applications
- Neutrino Physics Research
- Black Holes and Theoretical Physics
- Astrophysics and Cosmic Phenomena
- Medical Imaging Techniques and Applications
- Radiation Detection and Scintillator Technologies
- Distributed and Parallel Computing Systems
- Atomic and Subatomic Physics Research
- Nuclear reactor physics and engineering
- Particle Accelerators and Free-Electron Lasers
- Nuclear physics research studies
- Muon and positron interactions and applications
- Neural Networks and Applications
- Nuclear Physics and Applications
- Advanced Data Storage Technologies
- Theoretical and Computational Physics
- Gamma-ray bursts and supernovae
- Scientific Computing and Data Management
- Quantum Computing Algorithms and Architecture
LIP - Laboratory of Instrumentation and Experimental Particle Physics
2016-2025
Institute of High Energy Physics
2015-2024
University of Lisbon
2005-2024
Instituto Politécnico de Lisboa
1996-2024
University of Antwerp
2024
A. Alikhanyan National Laboratory
2022-2024
Administração Regional de Saúde de Lisboa e Vale do Tejo
2024
Universidade Federal do Rio de Janeiro
2014-2023
Instituto Superior Técnico
2009-2023
Joint Institute for Nuclear Research
2011-2023
We report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions at the CERN SPS. A significant excess is observed above yield expected from neutral meson decays. The unprecedented sample size 360 000 dimuons and good mass resolution about 2% allow us to isolate by subtraction decay sources. shape resulting spectrum consistent with dominant contribution...
We highlight issues which are often underestimated in the experimental analyses on quarkonium polarization: relation between parameters of angular distributions and momentum composition quarkonium, importance choice reference frame, interplay observed decay production kinematics, consequent influence acceptance comparison measurements theoretical calculations. Given puzzles raised by available results, new must provide more detailed information, such that physical conclusions can be derived...
The NA60 experiment at the CERN SPS has studied low-mass muon pairs in 158A GeV In-In collisions. mass and pT spectra associated with peripheral collisions can quantitatively be described by known neutral meson decays. high data quality allowed to remeasure electromagnetic transition form factors of Dalitz decays η-> μ^+μ^-γand ω-> μ^+μ^-π^0. Using usual pole approximation F = (1-M_{μμ}^{2}/Λ^{2})^{-1} for factors, we find Λ^{-2} (in GeV^{-2}) 1.95+-0.17(stat.)+-0.05(syst.) ηand...
Polarization measurements are usually considered as the most difficult challenge for QCD description of quarkonium production. In fact, global data fits determination non-perturbative parameters bound-state formation traditionally exclude polarization observables and use them a posteriori verifications predictions, with perplexing results. With change perspective, we move to centre study, advocating that they actually provide strongest fundamental indications about production mechanisms,...
The NA60 experiment studies muon pair production at the CERN Super Proton Synchrotron. In this Letter we report on a precision measurement of J/ψ in In-In collisions. We have studied centrality distribution, and compared it with one expected if absorption cold nuclear matter were only active suppression mechanism. For collisions involving more than ∼80 participant nucleons, find that an extra is present. This result qualitative agreement previous Pb-Pb measurements by NA50 experiment, but no...
The yield of muon pairs in the invariant mass region 1
The currently predicted increase in computational demand for the upcoming High-Luminosity Large Hadron Collider (HL-LHC) event reconstruction, and particular jet clustering, is bound to challenge present day computing resources, becoming an even more complex combinatorial problem. In this paper, we show that quantum annealing can tackle dijet clustering by introducing a novel binary algorithm. benchmarked efficiency of order $96\%$, thus yielding substantial improvements over current...
The NA60 experiment at the CERN SPS has studied low-mass dimuon production in 158A GeV In-In collisions. An excess of pairs above known meson decays been reported before. We now present precision results on associated transverse momentum spectra. slope parameter Teff extracted from spectra rises with mass up to ρ, followed by a sudden decline above. While initial rise is consistent expectations for radial flow hadronic decay source, signals transition an emission source much smaller flow....
The NA60 experiment at the CERN SPS has measured muon pairs with unprecedented precision in 158A GeV In-In collisions. A strong excess of above known sources is observed whole mass region 0.2 rho -> mu+mu- annihilation. associated spectral function shows a broadening, but essentially no shift mass. For M>1 GeV, found to be prompt, not due enhanced charm production, pronounced differences Drell-Yan pairs. slope parameter Teff transverse momentum spectra rises up rho, followed by sudden...
The NA60 experiment studied low-mass muon pair production in proton–nucleus (p–A) collisions using a 400 GeV proton beam at the CERN SPS. dimuon spectrum is well described by superposition of two-body and Dalitz decays light neutral mesons η, ρ, ω, η′ ϕ, no evidence in-medium effects found. A new high-precision measurement electromagnetic transition form factors η ω was performed, profiting from 10 times larger data sample than peripheral In–In previously collected NA60. Using...
One of the most ambitious goals quantum simulation field theory is description scattering in real time, which would allow not only for computation amplitudes, but also studying collision process step by step. The initial state such made typically two wavepackets moving on top vacuum, whose preparation hard. Some proposals are based a modified adiabatic transformation free into interacting wavepackets, this suitable chromodynamics (QCD). Other approaches used one-dimensional lattice gauge...
The covariance properties of angular momentum eigenstates imply the existence a rotation-invariant relation among parameters difermion decay distribution inclusively observed vector mesons. This is generalization Lam-Tung identity, result specific to Drell-Yan production in perturbative QCD, here shown be equivalent dynamical condition that dilepton always produced transversely polarized with respect quantization axes belonging plane.
Significant progress in understanding quarkonium production requires improved polarization measurements, fully considering the intrinsic multidimensionality of problem. We propose a frame-invariant formalism which minimizes dependence measured result on experimental acceptance, facilitates comparison with theoretical calculations, and provides much needed control over systematic effects due to detector limitations analysis biases. This is direct generic consequence rotational invariance...
To investigate the fundamental nature of matter and its interactions, particles are accelerated to very high energies collided inside detectors, producing a multitude other that scattered in all directions. As charged traverse detector, they leave signals their passage. The problem track reconstruction is recover original trajectories from these signals. This challenging data analysis task will become even more demanding as luminosity future accelerators increases, leading collision events...
The last few years have seen rapid development of applications quantum computation to field theory. first algorithms for simulation scattering been proposed in the context scalar and fermionic theories, requiring thousands logical qubits. These are not suitable simulate incoming bound states, as initial-state preparation relies typically on adiabatically transforming wavepackets free theory into interacting In this paper we present a strategy excite directly from vacuum theory, allowing...
Magnitude and "sign" of the measured J / psi polarization crucially depends on reference frame used in data analysis: a full understanding phenomenon requires measurements reported two "orthogonal" frames, such as Collins-Soper helicity frames. Moreover, azimuthal anisotropy can be, certain significant polar one. The seemingly contradictory results by experiments E866, HERA-B, CDF be consistently described assuming that most suitable axis for measurement is along direction relative motion...
The coefficients determining the dilepton decay angular distribution of vector particles obey certain positivity constraints and a rotation-invariant identity. These relations are direct consequence covariance properties momentum eigenstates independent production mechanism. Lam-Tung relation can be derived as particular case, simply recognizing that Drell-Yan is always produced transversely polarized with respect to one or more quantization axes. continues characterized by frame-independent...