Hyperfine interaction measurements on ceramics: PZT revisited

The solid solution of PbZr1-xTixO3, known as lead-zirconate titanate (PZT), was probably one of the most studied ferroelectric materials, especially due to its excellent dielectric, ferroelectric and piezoelectric properties. The highest piezoelectric coefficients of the PZT are found near the morphotropic phase boundary (MPB) (0.46 <= x <= 0.49), between the tetragonal and rhombohedral regions of the composition-temperature phase diagram. Recently, a new monoclinic phase near the MPB was observed, which can be considered as a bridge between PZT's tetragonal and rhombohedral phases. This work is concerned with the study of the structural properties of the ferroelectric PZT (Zr/Ti = 52/48, 53/47) by hypertine interaction (HI) measurements obtained from experiments performed by using the nuclear spectroscopy time differential perturbed angular correlation (TDPAC) in a wide temperature range. (c) 2006 Elsevier B.V. All rights reserved.

Measurement of the angular and lifetime parameters of the decays Bd0→J/ψK*0 and Bs0→J/ψ

We present measurements of the linear polarization amplitudes and the strong relative phases that describe the flavor-untagged decays Bd0→J/ψK*0 and Bs0→J/ψ in the transversity basis. We also measure the mean lifetime τ̄s of the Bs0 mass eigenstates and the lifetime ratio τ̄s/τd. The analyses are based on approximately 2.8fb-1 of data recorded with the D0 detector. From our measurements of the angular parameters we conclude that there is no evidence for a deviation from flavor SU(3) symmetry for these decays and that the factorization assumption is not valid for the Bd0→J/ψK*0 decay. © 2009 The American Physical Society.

Long-range and short-range dihadron angular correlations in central PbPb collisions at psNN = 2:76 TeV

First measurements of dihadron correlations for charged particles are presented for central PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76TeV over a broad range in relative pseudorapidity (Δν) and the full range of relative azimuthal angle (Δø). The data were collected with the CMS detector, at the LHC. A broadening of the away-side (Δø y≈ π) azimuthal correlation is observed at all Δν, as compared to the measurements in pp collisions. Furthermore, long-range dihadron correlations in Δν are observed for particles with similar ø values. This phenomenon, also known as the \ridge, persists up to at least jΔνj = 4. For particles with transverse momenta (pT) of 2-4 GeV/c, the ridge is found to be most prominent when these particles are correlated with particles of pT = 2-6 GeV/c, and to be much reduced when paired with particles of pT = 10-12 GeV/c. Copyright CERN.

Measurement of the cross section and angular correlations for associated production of a Z boson with b hadrons in pp collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Angular analysis and branching fraction measurement of the decay B-0 -> K*(0)mu(+)mu(-)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Measurements of t(t)over-bar Spin Correlations and Top-Quark Polarization Using Dilepton Final States in pp Collisions at root s=7 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Time differential perturbed angular correlation (TDPAC) study of some hafnium glycolate complexes

Time differential measurements of the 133-482 keV γ-γ angular correlation of 181Ta have been performed in solid hafnium complexes of the type [Hf(glycol)4] (glycol = p-chloromandelate, p-bromomandelate, b-naphthylglycolate and mandelate). The quadrupolar frequencies (ωQ) were found to increase within the series. This behaviour was explained by supposing a dissipation of electronic density at the metal level, caused by an increase in intermolecular hydrogen bonding in the complexes throughout the series studied. These results seem to agree with complementary data from IR spectroscopic studies. © 1988.

Aplicação de sensor de deslocamento angular em fibra óptica para medição de concentração de líquidos via ondas acústicas guiadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)