12 research outputs found
Level-spacing distribution of a fractal matrix
We diagonalize numerically a Fibonacci matrix with fractal Hilbert space
structure of dimension We show that the density of states is
logarithmically normal while the corresponding level-statistics can be
described as critical since the nearest-neighbor distribution function
approaches the intermediate semi-Poisson curve. We find that the eigenvector
amplitudes of this matrix are also critical lying between extended and
localized.Comment: 6 pages, Latex file, 4 postscript files, published in Phys. Lett.
A289 pp 183-7 (2001
Quantum correlations from Brownian diffusion of chaotic level-spacings
Quantum chaos is linked to Brownian diffusion of the underlying quantum
energy level-spacing sequences. The level-spacings viewed as functions of their
order execute random walks which imply uncorrelated random increments of the
level-spacings while the integrability to chaos transition becomes a change
from Poisson to Gauss statistics for the level-spacing increments. This
universal nature of quantum chaotic spectral correlations is numerically
demonstrated for eigenvalues from random tight binding lattices and for zeros
of the Riemann zeta function.Comment: 4 pages, revtex file, 4 postscript file
Measurement of the differential cross section for the production of an isolated photon with associated jet in ppbar collisions at sqrt(s)=1.96 TeV
The process ppbar -> photon + jet + X is studied using 1.0 fb^-1 of data
collected by the D0 detector at the Fermilab Tevatron ppbar collider at a
center-of-mass energy sqrt(s)=1.96 TeV. Photons are reconstructed in the
central rapidity region |y_gamma|<1.0 with transverse momenta in the range
30<Pt_gamma<400 GeV while jets are reconstructed in either the central
|y_jet|15 GeV.
The differential cross section d^3sigma/dPt_gamma dy_gamma dy_jet is measured
as a function of Pt_gamma in four regions, differing by the relative
orientations of the photon and the jet in rapidity. Ratios between the
differential cross sections in each region are also presented. Next-to-leading
order QCD predictions using different parameterizations of parton distribution
functions and theoretical scale choices are compared to the data. The
predictions do not simultaneously describe the measured normalization and
Pt_gamma dependence of the cross section in any of the four measured regions.Comment: 13 pages, 10 figure
Sarcopenia: its assessment, etiology, pathogenesis, consequences and future
Sarcopenia is a loss of muscle protein mass and loss of muscle function. It occurs with increasing age, being a major component in the development of frailty. Current knowledge on its assessment, etiology, pathogenesis, consequences and future perspectives are reported in the present review. On-going and future clinical trials on sarcopenia may radically change our preventive and therapeutic approaches of mobility disability in older peopleY. Rolland, S. Czerwinski, G. Abellan Van Kan, J.E. Morley, M. Cesari, G. Onder, J. Woo, R. Baumgartner, F. Pillard, Y. Boirie, W.M.C. Chumlea, B. Vella
Evidence for a Particle Produced in Association with Weak Bosons and Decaying to a Bottom-Antibottom Quark Pair in Higgs Boson Searches at the Tevatron
We combine searches by the CDF and D0 Collaborations for the associated production of a Higgs boson with a W or Z boson and subsequent decay of the Higgs boson to a bottom-antibottom quark pair. The data, originating from Fermilab Tevatron p[bar over p] collisions at √s=1.96 TeV, correspond to integrated luminosities of up to 9.7 fb[superscript -1]. The searches are conducted for a Higgs boson with mass in the range 100–150 GeV/c[superscript 2]. We observe an excess of events in the data compared with the background predictions, which is most significant in the mass range between 120 and 135 GeV/c[superscript 2]. The largest local significance is 3.3 standard deviations, corresponding to a global significance of 3.1 standard deviations. We interpret this as evidence for the presence of a new particle consistent with the standard model Higgs boson, which is produced in association with a weak vector boson and decays to a bottom-antibottom quark pair