Doutorado em Física (IF)
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Navegando Doutorado em Física (IF) por Por Orientador "Gomes, Ricardo Avelino"
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Item Decoerência quântica em neutrinos de aceleradores(Universidade Federal de Goiás, 2019-03-18) Gomes, Abner Leonel Gadelha; Gomes, Ricardo Avelino; http://lattes.cnpq.br/6538341799051577; Nunokawa, Hiroshi; Guzzo, Marcelo Moraes; Avelar, Ardiley Torres; Cardoso, Wesley Bueno; Gomes, Ricardo AvelinoIn this thesis we investigate the three flavor neutrino oscillation in vacuum considering the open quantum system framework. This allow us to introduce the quantum decoherence effects in the temporal evolution dynamics of neutrinos eigenstates. The characterization of this effect is given by Г12, Г13 and Г23 parameters, which are associated with the decoherence effects in which there is no neutrino energy dissipation, and the Г33 and Г88, which correspond to possible dissipative effects. We propose some possible scenarios to investigate the effects of decoherence on neutrino systems. In each of these scenarios we assume only one parameter of decoherence Г. In our analysis we consider a phenomenology for the parameter of decoherence, which Γ has a neutrino energy (E) dependence, by a law-power given by n and by a constant γ0, which is the decoherence parameter without energy dependence. This is the parameterization most used in studies that include quantum decoherence in neutrinos, in which where we consider to this analysis, n=-2, 0, 2. This formalism was applied to the data of the disappearance analysis of MINOS FHC and in the neutrino run and anti-neutrino run configurations of both disappearance and appearence analysis of T2K. We had as aim obtain new possibles limits to the quantum decoherence with the analyzed data to the different proposed scenarios. We have showed that for n=-2 and n=0 we obtained limits in the order of O(1E−23) GeV and for n=2, in the order of O(1E−25) GeV at level of 90% C.L. - Confidence Level. In particular for n=-2, we obtained a limit three orders of magnitude more constrained than the previous analysis (P. Coloma, J. Lopez-Pavon, I. Martinez-Soler and H. Nunokawa, Decoherence in Neutrino Propagation Through Matter, and Bounds from IceCube/DeepCore , Eur. Phys. J. C78 (2018) 614), where we obtained that γ0⩽1,69E-23 GeV at level of 90%C.L.. Through the investigated scenarios in this thesis we also were able to analyze the decoherence effect in the solar oscillation parameter (Г12 ≠ 0), of possibles dissipative effects (Г33 = Г88 ≠ 0) and the possibility of the oscillation phase be complex and it possibles consequences in the usual neutrino oscillation.Item Estudo da oscilação de neutrinos muônicos usando dados atmosféricos e de acelerador nos experimentos MINOS e MINOS+(Universidade Federal de Goiás, 2015-05-07) Medeiros, Michelle Mesquita de; Gomes, Ricardo Avelino; http://lattes.cnpq.br/6538341799051577; Gomes, Ricardo Avelino; Peres, Orlando Luis Goulart; Maciel, Arthur Kos Antunes; Leao, Salviano de Araujo; Celeri, Lucas ChibebeThe MINOS (Main Injector Neutrino Oscillation Search) and MINOS+ experiments were designed to study neutrino oscillations using a muon neutrino beam which is detected in two different locations, in the Near Detector and in the Far Detector. The distance between the detectors allows the beam neutrinos to oscillate to a different flavor. Therefore, a disappearance of the muon neutrinos from the beam is observed in the Far Detector. The Far Detector has a special apparatus which makes possible the selection of atmospheric neutrinos and antineutrinos. These come from interactions of cosmic rays with the Earth’s atmosphere. Both detectors have a magnetic field, allowing the distiction between neutrinos and antineutrinos interactions. This thesis presents the first combined analysis of data from the MINOS and MINOS+ experiments. We have analyzed the combined neutrino energy spectrum from the complete MINOS beam data and the first, more energetic, MINOS+ beam data. The disappearance of the muon neutrinos was observed and the data has shown to be congruent with the oscillation model. Beyond that, we have measured the atmospheric oscillation parameters of the beam and atmospheric neutrinos and antineutrinos from MINOS combined with the atmospheric neutrinos and antineutrinos from MINOS+. Assuming the same oscillation parameters for both neutrinos and antineutrinos, the best fit is obtained for inverted hierarchy and lower octant with m2 32 = 2:37 103 eV2 and sin2 23 = 0:43, and the limits m2 32 = [2,29 - 2,49] 103 eV2 (68%) and sin2 23 = 0.36 - 0.66 (90%). These results are the most precise measurement of the neutrinos mass splitting using muon neutrino disappearance data only.Item Simulação da razão de carga de múons atmosféricos utilizando o CORSIKA(Universidade Federal de Goiás, 2023-10-18) Paulo Júnior, Ademar; Gomes, Ricardo Avelino; http://lattes.cnpq.br/6538341799051577; Gomes, Ricardo Avelino; Peixoto, Carlos José Todero; Valdiviesso, Gustavo do Amaral; Tognini, Stefano Castro; Braghin, Fábio LuisThe muon charge ratio, $R_{\mu} = N_{\mu^{+}}/N_{\mu^{-}}$, is a quantity that can be measured both at at different altitude levels from Earth's surface and in underground experiments. The muons result from the hadronic interactions developed in extensive air showers (EAS) created from the interaction of cosmic rays with nuclei in the atmosphere. The muon charge ratio allows obtaining important information both from the point of view of physics involving cosmic rays, and from the study of the ratio between neutrinos and antineutrinos, $\nu/\bar{\nu}$, since their production is directly connected to the muons. The present work is a study using Monte Carlo simulations of EAS produced by cosmic rays with energy between 100 and $10^{6}$ GeV generated by CORSIKA, using the high energy hadronic interaction models: QGSJETII-04, EPOS -LHC, DPMJET III, SYBILL 2.3c, VENUS and QGSJET01-C. EAS were simulated separately with protons as primaries and He nuclei, and these datasets were combined in the performed analyses. Simulations aimed to verify which one of these hadronic interaction models are able to reproduce the expected behavior for the energies involved considering the increase of $R_{\mu}$ due to the contribution of the kaons to the EAS. It was observed that, to the set formed by protons and He nuclei, with the exception of DPMJET, the other models reproduce an increase in $R_{\mu}$ as a function of the energy of the muons on the surface $E_{\mu }\cos\theta^{*}$. However, when compared to the data obtained in the MINOS, OPERA and CMS experiments, the results, in general, does not reproduce the increase in $R_{\mu}$. Our results show that it would be useful to improve these models so that they can reproduce the expected behavior of the muon charge ratio.Item Observação da variação sazonal de múons múltiplos no NOvA Near Detector(Universidade Federal de Goiás, 2018-04-26) Tognini, Stefano Castro; Gomes, Ricardo Avelino; http://lattes.cnpq.br/6538341799051577; Gomes, Ricardo Avelino; Goodman, Maury Charles; Bolzam, Maurício José Alves; Braghin, Fábio Luis; Almeida, Norton Gomes deThe interaction of a cosmic ray particle with an element of the atmosphere results in a cascade of particles, known as extensive air showers, which can be divided into three main branches, known as the hadronic, the electromagnetic, and the muonic component. As for the latter, since muons can reach high depths underground, they are generally used to study cosmic rays at different underground depths. The dynamics of extensive air showers is directly connected to the density of the atmosphere, as it defines the probability of particles to decay or interact. As muons are mainly produced from the decay of pions and kaons, and a warmer atmosphere results in higher number of meson decays, such particles are prone to suffer a sea- sonality effect that is directly correlated to the yearly seasonal variations of the atmosphere, an effect that has been verified by a large number of experiments over the past six decades. In 2015 the MINOS experiment presented an anti correlation between the effective temperature of the atmosphere and the seasonality of the muon flux for multiplicities higher than one (i.e. more than one muon track per cosmic ray event). Said anti correlation is not yet fully understood, counting with only a qualitative hypothesis as a probable mechanism. As such, the main goals of this study are to verify the MINOS anti correlation effect and extend the study to verify the seasonality of the effect as a function of different variables in order to improve the understanding of the phenomenon and possible corroborations with the known hypothesis. Two full years of the NOνA Near Detector, ranging from April 2015 to April 2017, were used as the dataset for the analysis. The anti correlation between the multiple muon flux and the effective temperature of the atmosphere is confirmed by the NOνA Near Detector, being in full agreement with the results presented by the MINOS Collaboration. The seasonal effect is also broken down by different variables: i) track separation, ii) zenith angle, iii) track angular separation, and iv) multiplicity. Different regions of these variables represent different energy ranges for the detected underground muons, their hadron parents or the primary particles that originated the cosmic ray shower, being a way to verify any particular dependency with energy. The results show that there are no clear trends in any of the studied variables, except for the multiplicity, in which the intensity of the seasonal variation increases for higher multiplicities.