1,068 research outputs found
Decays of the Meson to a -Wave Charmonium State or
The semileptonic decays,
, and the two-body
nonleptonic decays, , (here and
denote and respectively, and
indicates a meson) were computed. All of the form factors appearing in the
relevant weak-current matrix elements with as its initial state and a
-wave charmonium state as its final state for the decays were precisely
formulated in terms of two independent overlapping-integrations of the
wave-functions of and the -wave charmonium and with proper kinematics
factors being `accompanied'. We found that the decays are quite sizable, so
they may be accessible in Run-II at Tevatron and in the foreseen future at LHC,
particularly, when BTeV and LHCB, the special detectors for B-physics, are
borne in mind. In addition, we also pointed out that the decays may potentially be used as a fresh window to look for the
charmonium state, and the cascade decays,
() with one of the radiative decays
being followed accordingly, may affect
the observations of meson through the decays () substantially.Comment: 24 pages, 3 figures, the replacement for improving the presentation
and adding reference
The meson annihilation to leptons and inclusive light hadrons
The annihilation of the meson to leptons and inclusive light hadrons is
analyzed in the framework of nonrelativistic QCD (NRQCD) factorization. We find
that the decay mode, which escapes from the helicity suppression, contributes a
sizable fraction width. According to the analysis, the branching ratio due to
the contribution from the color-singlet component of the meson can be of
order (10^{-2}). We also estimate the contributions from the color-octet
components. With the velocity scaling rule of NRQCD, we find that the
color-octet contributions are sizable too, especially, in certain phase space
of the annihilation they are greater than (or comparative to) the color-singlet
component. A few observables relevant to the spectrum of charged lepton are
suggested, that may be used as measurements on the color-octet and
color-singlet components in the future experiments. A typical long
distance contribution in the annihilation is estimated too.Comment: 26 pages, 5 figures (6 eps-files), submitted to Phys. Rev.
Study of wind loading on tall structures: Atlantic-Richfield Plaza buildings, A
CER68-69WZS-JEC-GH-36.August 1969.Includes bibliographical references.For Metronics Associates, Inc.Wind loading on a 1:384 scale model of Atlantic-Richfield Plaza Buildings 666 ft. high was investigated in a thick turbulent boundary-layer wind tunnel. Measurements of mean velocity, turbulence intensity and boundary-layer thickness upstream of the model structure verified that the wind-tunnel flow was an adequate simulation of the atmospheric-surface-layer conditions over the full-scale urban area. Mean pressure and pressure fluctuations were measured for three different wind directions (NE, N and NW). Generally, the mean pressure was found to be the largest near the top and smallest close to the base. An opposite variation was observed for the fluctuating and instantaneous peak pressures. The largest pressure fluctuations were obtained in the case of the N wind. The turbulence energy spectra of the upstream flow and surface pressure-fluctuations spectra exhibited consistently a similar qualitative behavior. This is suggestive that the upstream turbulence has a predominant role, together with the wake, in producing the pressure fluctuations. Direct measurement of mean and fluctuating overturning moment by means of a strain-gage dynamometer revealed that the latter ranged up to about ± 34% of the former. Root-mean square values of the fluctuating moment were also determined in an effort to relate it to the pressure fluctuations and upstream turbulence
Wind study of Kaiser Center office building
CER69-70GH-JEC-WZS-13.September 1969.For Metronics Associates, Inc.Includes bibliographical references.Mean and fluctuating wind loading on a 1:192 scale model of Kaiser Center Office Building 403 ft high was studied in a uniform flow. Pressure measurements were carried out for four different wind directions (N, NE, E, and S). The wind loading was influenced strongly by a tall building immediately to the southeast when the wind was from the south, Generally, the mean pressure was higher at the center portion of an upwind face than near its edges. On the leewind surface relatively uniform negative pressure (suction) was obtained. Its absolute value was about one-third of that along an upwind face. On the other hand, the fluctuating pressure was highest near the building base, in the flow separation region and in the wake of the adjacent building in a southly wind. A model of the upstream topography to the northeast was constructed using a 1:600 scale. This model terrain was 24 ft long (2.7 miles of the prototype terrain) with the Kaiser building site near its trailing edge. Mean velocity and turbulence intensity profiles were measured along the terrain
Perfect simulation from unbiased simulation
We show that any application of the technique of unbiased simulation becomes
perfect simulation when coalescence of the two coupled Markov chains can be
practically assured in advance. This happens when a fixed number of iterations
is high enough that the probability of needing any more to achieve coalescence
is negligible; we suggest a value of . This finding enormously
increases the range of problems for which perfect simulation, which exactly
follows the target distribution, can be implemented. We design a new algorithm
to make practical use of the high number of iterations by producing extra
perfect sample points with little extra computational effort, at a cost of a
small, controllable amount of serial correlation within sample sets of about 20
points. Different sample sets remain completely independent. The algorithm
includes maximal coupling for continuous processes, to bring together chains
that are already close. We illustrate the methodology on a simple, two-state
Markov chain and on standard normal distributions up to 20 dimensions. Our
technical formulation involves a nonzero probability, which can be made
arbitrarily small, that a single perfect sample point may have its place taken
by a "string" of many points which are assigned weights, each equal to ,
that sum to~. A point with a weight of is a "hole", which is an object
that can be cancelled by an equivalent point that has the same value but
opposite weight .Comment: 17 pages, 4 figures; for associated R scripts, see
https://github.com/George-Leigh/PerfectSimulatio
Kinegami: Algorithmic Design of Compliant Kinematic Chains From Tubular Origami
Origami processes can generate both rigid and compliant structures from the same homogeneous sheet material. In this article, we advance the origami robotics literature by showing that it is possible to construct an arbitrary rigid kinematic chain with prescribed joint compliance from a single tubular sheet. Our “Kinegami” algorithm converts a Denavit–Hartenberg specification into a single-sheet crease pattern for an equivalent serial robot mechanism by composing origami modules from a catalogue. The algorithm arises from the key observation that tubular origami linkage design reduces to a Dubins path planning problem. The automatically generated structural connections and movable joints that realize the specified design can also be endowed with independent user-specified compliance. We apply the Kinegami algorithm to a number of common robot mechanisms and hand-fold their algorithmically generated single-sheet crease patterns into functioning kinematic chains. We believe this is the first completely automated end-to-end system for converting an abstract manipulator specification into a physically realizable origami design that requires no additional human input
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