136 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
Closed-flavor pi + J/psi and pi + Upsilon Cross Sections at Low Energies from Dipion Decays
The scale of low energy c-cbar and b-bbar cross sections on light hadrons is
of great importance to searches for the quark gluon plasma using the
heavy-quarkonium suppression signature. Unfortunately, little is known about
these near-threshold cross sections at present, and recent theoretical
estimates span many orders of magnitude. Here we use experimental data on the
four observed closed-flavor heavy quarkonium hadronic decays psi' -> pi pi
J/psi, Upsilon' -> pi pi Upsilon, Upsilon'' -> pi pi Upsilon and Upsilon'' ->
pi pi Upsilon', combined with simple models of the transition amplitudes, to
estimate the pion scattering cross sections of c-cbar and b-bbar mesons near
threshold. Specifically we consider the closed-flavor reactions pi J/psi -> pi
psi', pi Upsilon -> pi Upsilon', pi Upsilon -> pi Upsilon'' and pi Upsilon' ->
pi Upsilon'' and their time-reversed analogues. Our results may be useful in
constraining theoretical models of the strong interactions of heavy quarkonia,
and can be systematically improved through future detailed studies of dipion
decays, notably psi' -> pi pi J/psi and Upsilon'' -> pi pi Upsilon.Comment: 6 pages, 6 figure
Heavy Quark Solitons
We investigate the heavy baryons which arise as solitonic excitations in a
``heavy meson" chiral Lagrangian which includes the light vector particles. It
is found that the effect of the light vectors may be substantial. We also
present a simple derivation which clearly shows the connection to the
Callan-Klebanov approach.Comment: 13 pages; LaTex; SU-4240-532; UR 1306/ER-40685-755 (Minor typos
corrected
Heavy Quark Solitons: Strangeness and Symmetry Breaking
We discuss the generalization of the Callan-Klebanov model to the case of
heavy quark baryons. The light flavor group is considered to be and the
limit of heavy spin symmetry is taken. The presence of the Wess-Zumino-Witten
term permits the neat development of a picture , at the collective level, of a
light diquark bound to a ``heavy" quark with decoupled spin degree of freedom.
The consequences of symmetry breaking are discussed in detail. We point
out that the mass splittings of the heavy baryons essentially measure
the ``low energy" physics once more and that the comparison with experiment is
satisfactory.Comment: 17 pages, RevTEX. Minor typos corrected and new references adde
J/psi absorption by pi and rho mesons in a meson exchange model with anomalous parity interactions
We reanalyze the dissociation process of the by and
mesons into , , , and within a meson exchange model. In addition to the dissociation
mechanisms considered in the literature, we consider anomalous parity
interactions, whose couplings are constrained by heavy quark spin symmetry and
phenomenology. This opens new dissociation channels and adds new diagrams in
the previously considered processes. Compared to the previous results, we find
that these new additions have only a minor effect on the total
inelastic cross section, but reduce the one for by about 50 %
near the threshold.Comment: 21 pages, REVTeX, 7 figures, references added, to appear in Phys.
Rev.
Excited states of heavy baryons in the Skyrme model
We obtain the spectra of excited heavy baryons containing one heavy quark by
quantizing the exactly-solved heavy meson bound states to Skyrme soliton. The
results are comparable to the recent experimental observations and quark model
predictions, and are consistent with the heavy quark spin symmetry. However,
somewhat large dependence of the results on the heavy quark mass strongly calls
for the incorporation of the soliton-recoil effects.Comment: 24 pages, REVTeX, epsf.sty, 7 figures in uuencoded fil
Neutrophils in cancer: neutral no more
Neutrophils are indispensable antagonists of microbial infection and facilitators of wound healing. In the cancer setting, a newfound appreciation for neutrophils has come into view. The traditionally held belief that neutrophils are inert bystanders is being challenged by the recent literature. Emerging evidence indicates that tumours manipulate neutrophils, sometimes early in their differentiation process, to create diverse phenotypic and functional polarization states able to alter tumour behaviour. In this Review, we discuss the involvement of neutrophils in cancer initiation and progression, and their potential as clinical biomarkers and therapeutic targets
Heavy quarkonium: progress, puzzles, and opportunities
A golden age for heavy quarkonium physics dawned a decade ago, initiated by
the confluence of exciting advances in quantum chromodynamics (QCD) and an
explosion of related experimental activity. The early years of this period were
chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in
2004, which presented a comprehensive review of the status of the field at that
time and provided specific recommendations for further progress. However, the
broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles
could only be partially anticipated. Since the release of the YR, the BESII
program concluded only to give birth to BESIII; the -factories and CLEO-c
flourished; quarkonium production and polarization measurements at HERA and the
Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the
deconfinement regime. All these experiments leave legacies of quality,
precision, and unsolved mysteries for quarkonium physics, and therefore beg for
continuing investigations. The plethora of newly-found quarkonium-like states
unleashed a flood of theoretical investigations into new forms of matter such
as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the
spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b},
and b\bar{c} bound states have been shown to validate some theoretical
approaches to QCD and highlight lack of quantitative success for others. The
intriguing details of quarkonium suppression in heavy-ion collisions that have
emerged from RHIC have elevated the importance of separating hot- and
cold-nuclear-matter effects in quark-gluon plasma studies. This review
systematically addresses all these matters and concludes by prioritizing
directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K.
Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D.
Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A.
Petrov, P. Robbe, A. Vair
Psi(2S) -> pi^+ pi^- J/psi Decay Distributions
Using a sample of 3.8 M psi(2S) events accumulated with the BES detector, the
process psi(2S) -> pi^+ pi^- J/psi is studied. The angular distributions are
compared with the general decay amplitude analysis of Cahn. We find that the
dipion system requires some D-wave, as well as S-wave. On the other hand, the
J/psi-(pi pi) relative angular momentum is consistent with being pure S-wave.
The decay distributions have been fit to heavy quarkonium models, including the
Novikov-Shifman model. This model, which is written in terms of the parameter
kappa, predicts that D-wave should be present. We determine kappa = 0.183 +/-
0.002 +/- 0.003 based on the joint dipion mass - cos theta distribution. The
fraction of D-wave as a function of the dipion mass is found to decrease with
increasing dipion mass, in agreement with the model. We have also fit the
Mannel-Yan model, another model that allows D-wave.Comment: 21 pages, 10 figure
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