28,968 research outputs found
Energy levels of the soliton--heavy-meson bound states
We investigate the bound states of heavy mesons with finite masses to a
classical soliton solution in the Skyrme model. For a given model Lagrangian we
solve the equations of motion exactly so that the heavy vector mesons are
treated on the same footing as the heavy pseudoscalar mesons. All the energy
levels of higher grand spin states as well as the ground state are given over a
wide range of the heavy meson masses. We also examine the validity of the
approximations used in the literatures. The recoil effect of finite mass
soliton is naively estimated.Comment: 24 pages, REVTeX v3.0, 6 figures are available upon request
Baryons with Two Heavy Quarks as Solitons
Using the chiral soliton model and heavy quark symmetry we study baryons
containing two heavy quarks. If there exists a stable (under strong
interactions) meson consisting of two heavy quarks and two light ones, then we
find that there always exists a state of this meson bound to a chiral soliton
and to a chiral anti-soliton, corresponding to a two heavy quark baryon and a
baryon containing two heavy anti-quarks and five light quarks, or a
``heptaquark".Comment: 7 pages and 2 postscript figures appended, LaTex, UCI-TR 94-3
Development of High Granulated Straw Chambers of Large Sizes
We have developed the baseline design for the straw drift tube tracking
detectors for high rate environment application. The low-mass inner straw
elements and the technology of the multianode straws assembly was devised and
checked. The prototype chamber was constructed and studied the granularity of
similar chambers can be reduced to one cm2.
Submitted to Physics of Elementary Particles and Atomic Nuclei, LettersComment: 6 pages, 10 figure
Constraints and Period Relations in Bosonic Strings at Genus-g
We examine some of the implications of implementing the usual boundary
conditions on the closed bosonic string in the hamiltonian framework. Using the
KN formalism, it is shown that at the quantum level, the resulting constraints
lead to relations among the periods of the basis 1-forms. These are compared
with those of Riemanns' which arise from a different consideration.Comment: 16 pages, (Plain Tex), NUS/HEP/9320
Hadronic decays of B involving a tensor meson through a transition
We re-analyze hadronic decays of B mesons to a pseudoscalar (P) and a tensor
meson (T), or a vector meson (V) and a tensor meson, through a
transition. We discuss possible large uncertainties to branching ratios (BR's)
of the relevant modes, mainly arising from uncertainties to the hadronic form
factors for the transition. The BR's and CP asymmetries for and VT decays are then calculated by using the form factors given in the
ISGW2 model (the improved version of the original Isgur-Scora-Grinstein-Wise
(ISGW) model). We find that the estimated BR's of many modes are increased by
an order of magnitude, compared to the previous results calculated within the
ISGW model.Comment: 22 pages, LaTex; minor clarifications included; to appear in Phys.
Rev.
Hyperons analogous to the \Lambda(1405)
The low mass of the hyperon with , which is
higher than the ground state mass by 290 MeV, is difficult to
understand in quark models. We analyze the hyperon spectrum in the bound state
approach of the Skyrme model that successfully describes both the
and the . This model predicts that several
hyperon resonances of the same spin but with opposite parity form parity
doublets that have a mass difference of around 300 MeV, which is indeed
realized in the observed hyperon spectrum. Furthermore, the existence of the
and the of is predicted by this model.
Comments on the baryons and heavy quark baryons are made as well.Comment: 4 pages, talk presented at the Fifth Asia-Pacific Conference on
Few-Body Problems in Physics 2011 (APFB2011), Aug. 22-26, 2011, Seoul, Kore
Performance of a prototype active veto system using liquid scintillator for a dark matter search experiment
We report the performance of an active veto system using a liquid
scintillator with NaI(Tl) crystals for use in a dark matter search experiment.
When a NaI(Tl) crystal is immersed in the prototype detector, the detector tags
48% of the internal K-40 background in the 0-10 keV energy region. We also
determined the tagging efficiency for events at 6-20 keV as 26.5 +/- 1.7% of
the total events, which corresponds to 0.76 +/- 0.04 events/keV/kg/day.
According to a simulation, approximately 60% of the background events from U,
Th, and K radioisotopes in photomultiplier tubes are tagged at energies of 0-10
keV. Full shielding with a 40-cm-thick liquid scintillator can increase the
tagging efficiency for both the internal K-40 and external background to
approximately 80%.Comment: Submitted to Nuclear Instruments and Methods in Physics Research
Section
Reverse geometric engineering of singularities
One can geometrically engineer supersymmetric field theories theories by
placing D-branes at or near singularities. The opposite process is described,
where one can reconstruct the singularities from quiver theories. The
description is in terms of a noncommutative quiver algebra which is constructed
from the quiver diagram and the superpotential. The center of this
noncommutative algebra is a commutative algebra, which is the ring of
holomorphic functions on a variety V. If certain algebraic conditions are met,
then the reverse geometric engineering produces V as the geometry that D-branes
probe. It is also argued that the identification of V is invariant under
Seiberg dualities.Comment: 17 pages, Latex. v2: updates reference
Generalization of the Bound State Model
In the bound state approach the heavy baryons are constructed by binding,
with any orbital angular momentum, the heavy meson multiplet to the nucleon
considered as a soliton in an effective meson theory. We point out that this
picture misses an entire family of states, labeled by a different angular
momentum quantum number, which are expected to exist according to the geometry
of the three-body constituent quark model (for N_C=3). To solve this problem we
propose that the bound state model be generalized to include orbitally excited
heavy mesons bound to the nucleon. In this approach the missing angular
momentum is ``locked-up'' in the excited heavy mesons. In the simplest
dynamical realization of the picture we give conditions on a set of coupling
constants for the binding of the missing heavy baryons of arbitrary spin. The
simplifications made include working in the large M limit, neglecting nucleon
recoil corrections, neglecting mass differences among different heavy spin
multiplets and also neglecting the effects of light vector mesons.Comment: 35 pages (ReVTeX), 2 PostScript Figure
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