654 research outputs found
Recovery and radiation corrections and time constants of several sizes of shielded and unshielded thermocouple probes for measuring gas temperature
Performance characteristics were experimentally determined for several sizes of a shielded and unshielded thermocouple probe design. The probes are of swaged construction and were made of type K wire with a stainless steel sheath and shield and MgO insulation. The wire sizes ranged from 0.03- to 1.02-mm diameter for the unshielded design and from 0.16- to 0.81-mm diameter for the shielded design. The probes were tested through a Mach number range of 0.2 to 0.9, through a temperature range of room ambient to 1420 K, and through a total-pressure range of 0.03 to 0.2.2 MPa (0.3 to 22 atm). Tables and graphs are presented to aid in selecting a particular type and size. Recovery corrections, radiation corrections, and time constants were determined
Quantum Dissipation in a Neutrino System Propagating in Vacuum and in Matter
Considering the neutrino state like an open quantum system, we analyze its
propagation in vacuum or in matter. After defining what can be called
decoherence and relaxation effects, we show that in general the probabilities
in vacuum and in constant matter can be written in a similar way, which is not
an obvious result in this approach. From this result, we analyze the situation
where neutrinos evolution satisfies the adiabatic limit and use this formalim
to study solar neutrinos. We show that the decoherence effect may not be
bounded by the solar neutrino data and review some results in the literature.
We discuss the current results where solar neutrinos were used to put bounds on
decoherence effects through a model-dependent approach. We conclude explaining
how and why this models are not general and we reinterpret these constraints.Comment: new version: title was changend and was added a table. To appear at
Nucl. Physic.
Parameter limits for neutrino oscillation with decoherence in KamLAND
FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQIn the framework of open quantum systems, we analyze data from KamLAND by using a model that considers neutrino oscillation in a three-family approximation with the inclusion of the decoherence effect. Using chi(2) test, we find new limits for the decoherence parameter, which we call gamma, considering the most recent data by KamLAND. Assuming an energy dependence of the type gamma=gamma(0) (E/E-0)(n), at a 95% C.L., the limits found are 3.7 x 10(-24) GeV for n=-1, 6.8 x 10(-22) GeV for n=0, and 1.5 x 10(-19) GeV for n=1 on the energy dependence.951117FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESCONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQSem informaçãoSem informaçãoSem informaçã
Minimal 3-3-1 model, lepton mixing and muonium-antimuonium conversion
The recent experimental results on neutrino oscillation and on
muonium-antimuonium conversion require extension of the minimal 3-3-1 model. We
review the constraints imposed to the model by those measurements and suggest a
pattern of leptonic mixing, with charged leptons in a non-diagonal basis, which
accounts for the neutrino physics and circumvents the tight muonium-antimuonium
bounds on the model. We also illustrate a scenario where this pattern could be
realized.Comment: 4 pages; abbreviated version, conclusions unchange
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