8,909 research outputs found
High Mass Standard Model Higgs searches at the Tevatron
We present the results of searches for the Standard Model Higgs boson
decaying predominantly to WW pairs, at a center-of-mass energy of sqrt(s)=1.96
TeV, using up to 8.2 fb^{-1} of data collected with the CDF and D0 detectors at
the Fermilab Tevatron collider. The analysis techniques and the various
channels considered are discussed. These searches result in exclusions across
the Higgs mass range of 156.5<mH<173.7 GeV for CDF and 161<mH<170 GeV for D0.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 4 pages, 8 figure
Using the Balance Function to study the charge correlations of hadrons
We present the recent Balance Function (BF) results obtained by the NA49
collaboration for the pseudo-rapidity dependence of non-identified charged
particle correlations for two SPS energies. Experimental results indicate a
clear centrality dependence only in the mid-rapidity region. The results of an
energy dependence study of the BF throughout the whole SPS energy range will
also be discussed. In addition, the correlation of identified hadrons is
studied and presented for the first time. The study of hadron correlation has
also been extended in order to cope with the high multiplicity environment that
is expected to be seen at LHC. We will present the latest results from
simulations concerning the extension of these studies to the ALICE experiment.Comment: To appear in the proccedings of the "Quark Confinement and Hadron
Spectrum VII" conferenc
System Size and Centrality Dependence of the Electric Charge Correlations in A+A and p+p Collisions at the SPS Energies
The Balance Function analysis method was developed in order to study the long
range correlations in pseudo-rapidity of charged particle. The final results on
p+p, C+C, Si+Si and centrality selected Pb+Pb collisions at GeV and the preliminary data at GeV are presented.
The width of the Balance Function decreases with increasing system size and
centrality of the collisions. This could suggest a delayed hadronization
scenario.Comment: To appear in the proceedings of NPDC18, Prague, Czech Republic, 23-28
Aug. 200
Quenched disorder and spin-glass correlations in XY nematics
We present a theoretical study of the equilibrium ordering in a 3D XY nematic
system with quenched random disorder. Within this model, treated with the
replica trick and Gaussian variational method, the correlation length is
obtained as a function of the local nematic order parameter and the effective
disorder strength. These results clarify what happens in the limiting cases of
diminishing order parameter and disorder strength, that is near a phase
transition of a pure system. In particular, it is found that quenched disorder
is irrelevant as the order parameter tends to zero and hence does not change
the character of the continuous XY nematic to isotropic phase transition. We
discuss how these results compare with experiments and simulationsComment: 19 pages, 6 figures, corrected typo
Three-dimensional positional changes of teeth adjacent to posterior edentulous spaces in relation to age at time of tooth loss and elapsed time
The purpose of this study was to study the stability of teeth adjacent to posterior edentulous spaces and correlate it with patient age and time lapse since tooth loss. Dental casts, panoramic radiographs, and questionnaires of patients treated in a University setting were employed. Teeth adjacent and opposing posterior edentulous spaces were examined for the following parameters: Supraeruption, rotation, space closure, and axial inclination. One hundred twenty three patients with 229 edentulous spaces were analyzed. Statistical analysis showed that the effects of "jaw", "gender", and "age group at the time of tooth loss" were not significant for any of the variables tested. The effect of time lapse since tooth loss was significant regarding the "amount of distal tooth inclination" (P<0.001), the "amount of distal tooth rotation" (P=0.004), and "space closure" (P=0.038). Post-hoc analysis of the "amount of distal tooth inclination" revealed a marked increase in inclination 5 years after tooth loss. Within the limitations of this study, it was concluded that in the group of patients studied, minor positional changes in teeth opposing or adjacent to posterior edentulous spaces had occurred. The greatest changes in position were recorded for mandibular teeth distal to edentulous spaces
Nematic-Isotropic Transition with Quenched Disorder
Nematic elastomers do not show the discontinuous, first-order, phase
transition that the Landau-De Gennes mean field theory predicts for a
quadrupolar ordering in 3D. We attribute this behavior to the presence of
network crosslinks, which act as sources of quenched orientational disorder. We
show that the addition of weak random anisotropy results in a singular
renormalization of the Landau-De Gennes expression, adding an energy term
proportional to the inverse quartic power of order parameter Q. This reduces
the first-order discontinuity in Q. For sufficiently high disorder strength the
jump disappears altogether and the phase transition becomes continuous, in some
ways resembling the supercritical transitions in external field.Comment: 12 pages, 4 figures, to be published on PR
Transition Radiation Spectra of Electrons from 1 to 10 GeV/c in Regular and Irregular Radiators
We present measurements of the spectral distribution of transition radiation
generated by electrons of momentum 1 to 10 GeV/c in different radiator types.
We investigate periodic foil radiators and irregular foam and fiber materials.
The transition radiation photons are detected by prototypes of the drift
chambers to be used in the Transition Radiation Detector (TRD) of the ALICE
experiment at CERN, which are filled with a Xe, CO2 (15 %) mixture. The
measurements are compared to simulations in order to enhance the quantitative
understanding of transition radiation production, in particular the momentum
dependence of the transition radiation yield.Comment: 18 pages, 15 figures, submitted to Nucl. Instr. Meth. Phys. Res.
Can one hear the shape of the Universe?
It is shown that the recent observations of NASA's explorer mission
"Wilkinson Microwave Anisotropy Probe" (WMAP) hint that our Universe may
possess a non-trivial topology. As an example we discuss the Picard space which
is stretched out into an infinitely long horn but with finite volume.Comment: 4 page
- …
