215 research outputs found
Gluon Fragmentation into Spin-Triplet S-Wave Quarkonium
The leading color-singlet contribution to the fragmentation function for a
gluon to split into spin-triplet S-wave quarkonium is presented. In the case of
charmonium, we find that this color-singlet term is always negligible compared
to the leading color-octet contribution.Comment: 7 Latex page
Dark Matter Production Associated With a Heavy Quarkonium at B Factories
We investigate light dark matter production associated with a heavy
quarkonium at B factories in a model-independent way by adopting the effective
field theory approach for the interaction of dark matter with standard model
particles. We consider the effective operators for the dark matter-heavy quark
interaction, which are relevant to the production of dark matter associated
with a heavy quarkonium. We calculate the cross sections for dark matter
production associated with a J/psi or eta_c to compare with the standard model
backgrounds. We set bounds on the energy scale of new physics for various
effective operators and also obtain the corresponding limits for the dark
matter-nucleon scattering cross sections for light dark matter with mass of the
order of a few GeV.Comment: 13 pages, 5 figures, references adde
Partially Strong WW Scattering
What if only a light Higgs boson is discovered at the CERN LHC?
Conventional wisdom tells us that the scattering of longitudinal weak gauge
bosons would not grow strong at high energies. We show that this is not always
true. In some composite models, two-Higgs-doublet models, or even
supersymmetric models, the presence of a light Higgs boson does not guarantee
the complete unitarization of the scattering. After the partial
unitarization by the light Higgs boson, the scattering becomes strongly
interacting until it hits one or more heavier Higgs bosons or other strong
dynamics. We analyze how the LHC experiments can reveal this interesting
possibility of partially strong scattering.Comment: 4 pages, 3 figures; updated reference information and added a
referenc
Glueball Production via Gluonic Penguin B Decays
We study glueball production in gluonic penguin decay ,
using the next-to-leading order gluonic penguin interaction and
effective couplings of a glueball to two perturbative gluons. Subsequent decays
of a scalar glueball are described by using techniques of effective chiral
Lagrangian to incorporate the interaction between a glueball and pseudoscalar
mesons. Mixing effects between the pure glueball with other mesons are
considered. Identifying the to be a scalar glueball, we find that
both the top and charm penguin to be important and obtain a sizable branching
ratio for of order 1.3\times 10^{-4}
(f/0.07\mbox{GeV}^{-1})^2, where the effective coupling strength is
estimated to be GeV using experimental data for the branching
ratio of based on chiral Lagrangian estimate. An
alternative perturbative QCD based estimation of is a factor of 20 larger,
which would imply a much enhanced branching ratio. Glueball production from
this rare semi-inclusive decay can be probed at the LHCb and Belle II to
narrow down the allowed parameter space. Similar branching ratio is expected
for the pseudoscalar glueball. We also briefly comment on the case of vector
and tensor glueballs.Comment: Latex 14 pages with 2 figures. Significant update from the older
version of arXiv:hep-ph/0612108. Version to appear in Eur. Phys. J.
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