4,570 research outputs found
Stochastics theory of log-periodic patterns
We introduce an analytical model based on birth-death clustering processes to
help understanding the empirical log-periodic corrections to power-law scaling
and the finite-time singularity as reported in several domains including
rupture, earthquakes, world population and financial systems. In our
stochastics theory log-periodicities are a consequence of transient clusters
induced by an entropy-like term that may reflect the amount of cooperative
information carried by the state of a large system of different species. The
clustering completion rates for the system are assumed to be given by a simple
linear death process. The singularity at t_{o} is derived in terms of
birth-death clustering coefficients.Comment: LaTeX, 1 ps figure - To appear J. Phys. A: Math & Ge
Strain analysis of a seismically imaged massâtransport complex, offshore Uruguay
Strain style, magnitude and distribution within massâtransport complexes (MTCs) are important for understanding the process evolution of submarine mass flows and for estimating their runout distances. Structural restoration and quantification of strain in gravitationally driven passive margins have been shown to approximately balance between updip extensional and downdip contractional domains; such an exercise has not yet been attempted for MTCs. We here interpret and structurally restore a shallowly buried (c. 1,500 mbsf) and wellâimaged MTC, offshore Uruguay using a highâresolution (12.5 m vertical and 15 Ă 12.5 m horizontal resolution) threeâdimensional seismicâreflection survey. This allows us to characterise and quantify vertical and lateral strain distribution within the deposit. Detailed seismic mapping and attribute analysis shows that the MTC is characterised by a complicated array of kinematic indicators, which vary spatially in style and concentration. Seismicâattribute extractions reveal several previously undocumented fabrics preserved in the MTC, including internal shearing in the form of subâorthogonal shear zones, and foldâthrust systems within the basal shear zone beneath raftedâblocks. These features suggest multiple transport directions and phases of flow during emplacement. The MTC is characterised by a broadly tripartite strain distribution, with extensional (e.g. normal faults), translational and contractional (e.g. folds and thrusts) domains, along with a radial frontally emergent zone. We also show how strain is preferentially concentrated around intraâMTC raftedâblocks due to their kinematic interactions with the underlying basal shear zone. Overall, and even when volume loss within the frontally emergent zone is included, a strain deficit between the extensional and contractional domains (c. 3%â14%) is calculated. We attribute this to a combination of distributed, subâseismic, âcrypticâ strain, likely related to deâwatering, grainâscale deformation and related changes in bulk sediment volume. This work has implications for assessing MTCs strain distribution and provides a practical approach for evaluating structural interpretations within such deposits
New Particles Working Group Report of the Snowmass 2013 Community Summer Study
This report summarizes the work of the Energy Frontier New Physics working
group of the 2013 Community Summer Study (Snowmass)
Search for Top Squark Pair Production in the Dielectron Channel
This report describes the first search for top squark pair production in the
channel stop_1 stopbar_1 -> b bbar chargino_1 chargino_1 -> ee+jets+MEt using
74.9 +- 8.9 pb^-1 of data collected using the D0 detector. A 95% confidence
level upper limit on sigma*B is presented. The limit is above the theoretical
expectation for sigma*B for this process, but does show the sensitivity of the
current D0 data set to a particular topology for new physics.Comment: Five pages, including three figures, submitted to PRD Brief Report
A measurement of the W boson mass using large rapidity electrons
We present a measurement of the W boson mass using data collected by the D0
experiment at the Fermilab Tevatron during 1994--1995. We identify W bosons by
their decays to e-nu final states where the electron is detected in a forward
calorimeter. We extract the W boson mass, Mw, by fitting the transverse mass
and transverse electron and neutrino momentum spectra from a sample of 11,089 W
-> e nu decay candidates. We use a sample of 1,687 dielectron events, mostly
due to Z -> ee decays, to constrain our model of the detector response. Using
the forward calorimeter data, we measure Mw = 80.691 +- 0.227 GeV. Combining
the forward calorimeter measurements with our previously published central
calorimeter results, we obtain Mw = 80.482 +- 0.091 GeV
Search for Squarks and Gluinos in Events Containing Jets and a Large Imbalance in Transverse Energy
Using data corresponding to an integrated luminosity of 79 pb-1, D0 has
searched for events containing multiple jets and large missing transverse
energy in pbar-p collisions at sqrt(s)=1.8 TeV at the Fermilab Tevatron
collider. Observing no significant excess beyond what is expected from the
standard model, we set limits on the masses of squarks and gluinos and on the
model parameters m_0 and m_1/2, in the framework of the minimal low-energy
supergravity models of supersymmetry. For tan(beta) = 2 and A_0 = 0, with mu <
0, we exclude all models with m_squark < 250 GeV/c^2. For models with equal
squark and gluino masses, we exclude m < 260 GeV/c^2.Comment: 10 pages, 3 figures, Submitted to PRL, Fixed typo on page bottom of
p. 6 (QCD multijet background is 35.4 events
Measurement of the Boson Mass
A measurement of the mass of the boson is presented based on a sample of
5982 decays observed in collisions at
= 1.8~TeV with the D\O\ detector during the 1992--1993 run. From a
fit to the transverse mass spectrum, combined with measurements of the
boson mass, the boson mass is measured to be .Comment: 12 pages, LaTex, style Revtex, including 3 postscript figures
(submitted to PRL
Differential Production Cross Section of Z Bosons as a Function of Transverse Momentum at sqrt{s}=1.8 TeV
We present a measurement of the transverse momentum distribution of Z bosons
produced in ppbar collisions at sqrt{s}=1.8 TeV using data collected by the D0
experiment at the Fermilab Tevatron Collider during 1994--1996. We find good
agreement between our data and a current resummation calculation. We also use
our data to extract values of the non-perturbative parameters for a particular
version of the resummation formalism, obtaining significantly more precise
values than previous determinations.Comment: 10 pages, 2 figures, submitted to Phys. Rev. Letters v2 has margin
error correcte
Search for Production via Trilepton Final States in collisions at TeV
We have searched for associated production of the lightest chargino,
, and next-to-lightest neutralino, , of the
Minimal Supersymmetric Standard Model in collisions at
\mbox{ = 1.8 TeV} using the \D0 detector at the Fermilab Tevatron
collider. Data corresponding to an integrated luminosity of 12.5 \ipb
were examined for events containing three isolated leptons. No evidence for
pair production was found. Limits on
BrBr are
presented.Comment: 17 pages (13 + 1 page table + 3 pages figures). 3 PostScript figures
will follow in a UUEncoded, gzip'd, tar file. Text in LaTex format. Submitted
to Physical Review Letters. Replace comments - Had to resumbmit version with
EPSF directive
Measurement of the Branching Fraction for B- --> D0 K*-
We present a measurement of the branching fraction for the decay B- --> D0
K*- using a sample of approximately 86 million BBbar pairs collected by the
BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is
detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the
K*- through its decay to K0S pi-. We measure the branching fraction to be
B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid
Communications
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