48,364 research outputs found
Inclusive production at factories
Within the nonrelativistic QCD (NRQCD) factorization framework, we
investigate the inclusive production of the meson associated with either
light hadrons or charmed hadrons at factory energy GeV.
Both the leading color-singlet and color-octet channels are included. For the
production associated with light hadrons, the total production rate is
dominated by the color-octet channel, thus the future measurement of this
process may impose useful constraint on the value of the color-octet matrix
element ; for the production associated with
charmed hadrons, the total production rate is about one order of magnitude
smaller, and dominated by the color-singlet channel.Comment: v2, 23 pages, 1 table, 6 figures. Minor corrections, and a note
added, accepted for publication in PR
"Hard-scattering" approach to very hindered magnetic-dipole transitions in quarkonium
For a class of hindered magnetic dipole () transition processes, such as
(the discovery channel of the meson),
the emitted photon is rather energetic so that the traditional approaches based
on multipole expansion may be invalidated. We propose that a "hard-scattering"
picture, somewhat analogous to the pion electromagnetic form factor at large
momentum transfer, may be more plausible to describe such types of transition
processes. We work out a simple factorization formula at lowest order in the
strong coupling constant, which involves convolution of the Schr\"odinger wave
functions of quarkonia with a perturbatively calculable part induced by
exchange of one semihard gluon between quark and antiquark. This formula,
without any freely adjustable parameters, is found to agree with the measured
rate of rather well, and can also reasonably
account for other recently measured hindered transition rates. The
branching fractions of are also
predicted.Comment: v3; 5 pages, 1 figure and 1 table; title changed, presentation
improve
An algorithm for determining copositive matrices
In this paper, we present an algorithm of simple exponential growth called
COPOMATRIX for determining the copositivity of a real symmetric matrix. The
core of this algorithm is a decomposition theorem, which is used to deal with
simplicial subdivision of on
the standard simplex , where each component of the vector is
-1, 0 or 1.Comment: 15 page
Exclusive decay of into
We study the exclusive decay into double charmonium, specifically,
the -wave charmonium plus the -wave charmonium
in the NRQCD factorization framework. Three distinct decay mechanisms, i.e.,
the strong, electromagnetic and radiative decay channels are included and their
interference effects are investigated. The decay processes
are predicted to have the branching
fractions of order , which should be observed in the prospective Super
factory.Comment: 22 pages, 9 figures, 3 table
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