Search results for "Quark"
showing 10 items of 2905 documents
Hunting for new physics signals in the LHC era
2021
Actualment, el ME de física de partícules és capaç d’explicar satisfactòriament tres de les quatre interaccions fonamentals de la matèria: fortes, febles i electromagnètiques. Tot i això, hi han molts aspectes que aquesta fantàstica teoria no és capaç d’explicar i, sens dubte, ha d’haver alguna cosa més enllà d’aquesta teoria. En aquesta tesi es pretén descobrir si hi ha algun indici a les dades actuals dels acceleradors que suggerisca l’existència de nova física (NF). Pretenem, per tant, determinar fins a quin punt alguns dels models de NF que han sigut proposats a la literatura poden ser plausibles tenint en compte les dades actuals. D’aquesta forma, serem capaços de trobar restriccions s…
Measurements of inclusive jet spectra in pp and central Pb-Pb collisions at √sNN = 5.02 TeV
2020
This article reports measurements of the pT-differential inclusive jet cross section in pp collisions at √s = 5.02 TeV and the pT-differential inclusive jet yield in Pb-Pb 0-10% central collisions at √sNN = 5.02 TeV. Jets were reconstructed at midrapidity with the ALICE tracking detectors and electromagnetic calorimeter using the anti-kT algorithm. For pp collisions, we report jet cross sections for jet resolution parameters R=0.1-0.6 over the range 20<pT,jet<140 GeV/c, as well as the jet cross-section ratios of different R and comparisons to two next-to-leading-order (NLO)-based theoretical predictions. For Pb-Pb collisions, we report the R=0.2 and R=0.4 jet spectra for 40<pT,jet<140 GeV/c…
Measurement of top-quark polarisation observables and a search for dark matter in single-top-quark production with the ATLAS detector at the LHC
2022
Esta tesis presenta dos análisis diferentes basados en los datos resultantes de colisiones protón-protón a una energía en el centro de masas de 13 TeV recolectados con el detector ATLAS del LHC, correspondientes a una luminosidad integrada de 139 fb$^{-1}$. El primer análisis presenta una medida de secciones eficaces diferenciales normalizadas del canal de producción de quarks top en solitario $t$-channel, donde el quark top se desintegra leptónicamente, como función de los tres ángulos de polarización del leptón para eventos con quarks top y quarks antitop tanto separadamente como de forma inclusiva. Estos observables son particularmente sensibles a efectos de nueva física en el vértice $t…
Measurement of the top quark pair production cross-section involving a Tau & Muon Studies with TileCal in ATLAS
2014
200 páginas. Tesis Doctoral del Departamento de Física Atómica, Molecular y Nuclear de la Universidad de Valencia y del Instituto de Física Corpuscular (IFIC).
Measurements of the top quark branching ratios into channels with leptons and quarks with the ATLAS detector
2015
Measurements of the branching ratios of top quark decays into leptons and jets using events with t[bar over t] (top antitop) pairs are reported. Events were recorded with the ATLAS detector at the LHC in pp collisions at a center-of-mass energy of 7 TeV. The collected data sample corresponds to an integrated luminosity of 4.6 fb[superscript −1]. The measured top quark branching ratios agree with the Standard Model predictions within the measurement uncertainties of a few percent.
Performance of $b$-Jet Identification in the ATLAS Experiment
2016
We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF, DNSRC and Lundbeck Foundation, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT an…
Study of Σ(1385) and Ξ(1321) hyperon and antihyperon production in deep inelastic muon scattering
2013
Large samples of \Lambda, \Sigma(1385) and \Xi(1321) hyperons produced in deep-inelastic muon scattering off a ^6LiD target were collected with the COMPASS experimental setup at CERN. The relative yields of \Sigma(1385)^+, \Sigma(1385)^-, \bar{\Sigma}(1385)^-, \bar{\Sigma}(1385)^+, \Xi(1321)^-, and \bar{\Xi}(1321)^+ hyperons decaying into \Lambda(\bar{\Lambda})\pi were measured. The heavy hyperon to \Lambda and heavy antihyperon to \bar{\Lambda} yield ratios were found to be in the range 3.8% to 5.6% with a relative uncertainty of about 10%. They were used to tune the parameters relevant for strange particle production of the LEPTO Monte Carlo generator.
Inclusive photoproduction of bottom quarks for low and medium p T in the general-mass variable-flavour-number scheme
2016
We present predictions for b-quark production in photoprodcution and compare with experimental data from HERA. Our theoretical predictions are obtained at next-to-leading-order in the general-mass variable-flavor-number scheme, an approach which takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e+e- data. We find in general good agreement of data with both the GM-VFNS and the FFNS calculations, while the more precise ZEUS data seem to prefer the GM-VFNS predictions.
Precision measurement of the mass difference between light nuclei and anti-nuclei
2015
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons and anti-deuterons, and $^{3}{\rm He}$ and $^3\overline{\rm He}…
Remarks on strange-quark simulations with Wilson fermions
2020
Physical review / D 102(7), 074506 (1-10) (2020). doi:10.1103/PhysRevD.102.074506