259 research outputs found
Observation of the Decay \u3ci\u3eD\u3c/i\u3e\u3csub\u3es\u3c/sub\u3e\u3csup\u3e+\u3c/sup\u3e → ωπ\u3csup\u3e+\u3c/sup\u3e
Using e+e- annihilation data collected by the CLEO II detector at CESR, we have observed the decay Ds+ → ωπ+. This final state may be produced through the annihilation decay of the i\u3eDs+, or through final state interactions. We find a branching ratio of γ(Ds+ → ωπ+)/γ(Ds+ →ηπ+) = 0.16±0.04±0.03, where the first error is statistical and the second is systematic
Accounting for Slow J/psi from B Decay
A slow J/psi excess exists in the inclusive B -> J/psi+X spectrum, and is
indicative of some hadronic effect. From color octet nature of c cbar pair in
b-> c cbar s decay, one such possibility would be B -> J/psi+ K_g decay, where
K_g is a hybrid resonance with sbar g q constituents. We show that a K_g
resonance of ~ 2 GeV mass and suitably broad width could be behind the excess.Comment: 4 pages, 2 figures. To appear in Phys. Rev.
The Color-Octet intrinsic charm in and decays
Color-octet mechanism for the decay B\to \eta^\prime X is proposed to explain
the large branching ratio of Br(B\to \eta^\prime X)\sim 1\times 10^{-3}
recently announced by CLEO. We argue that the inclusive \eta^\prime production
in B decays may dominantly come from the Cabbibo favored b\to (\bar c c)_8s
process where \bar c c pair is in a color-octet configuration, and followed by
the nonperturbative transition (\bar c c)_8\to \eta^\prime X. The color-octet
intrinsic charm component in the higher Fock states of \eta^\prime is crucial
and is induced by the strong coupling of \eta^\prime to gluons via QCD axial
anomaly.Comment: 9 pages, RevTex, 1 PS figur
Chiral sum rules to second order in quark mass
A new calculation of the isospin and hypercharge axialvector current
propagators ( and ) to
two loops in SU(3) x SU(3) chiral perturbation theory is used to derive chiral
spectral function sum rules valid to second order in the light quark masses.
Explicit forms are given for the three-pion isospin axialvector spectral
functions at low energy and application of the sum rules to the determination
of counterterms of the chiral lagrangian is discussed.Comment: Figures extended down to threshold; Eq. (19) expressed in simplified
for
Chiral Perturbation Theory for , , and
We use heavy vector meson chiral perturbation theory
to predict differential decay distributions for and in the kinematic region where
(here or ) is much smaller than the
chiral symmetry breaking scale. Using the large number of colors limit we also
predict the rate for in this region (now
). Comparing our prediction with experimental data, we determine
one of the coupling constants in the heavy vector meson chiral Lagrangian.Comment: 14 pages, latex 2e. We include the decay of the tau into the omega,
pi minus and the tau neutrino, and extract a value for the coupling constant
g2, using experimental dat
Semileptonic and nonleptonic B decays to three charm quarks: B->J/psi (eta_c) D l nu and J/psi (eta_c) D pi
We evaluate the form factors describing the semileptonic decays , within the framework of a QCD
relativistic potential model. This decay is complementary to in a phase space region where a pion factors out.We
estimate the branching ratio for these semileptonic and nonleptonic channels,
finding ,
and .Comment: 14 pages, 4 figure
The Decay in the Context of Chiral Perturbation Theory
We study the decay , using
chiral perturbation theory for heavy charmed mesons
and vector mesons, in the kinematic regime where (here or ) is much smaller than the chiral symmetry breaking
scale, ( 1 GeV). We present the
leading diagrams and amplitude, and calculate the rate, in the region where, to
leading order in our calculations, the is at zero recoil in the
rest frame. The rate thus calculated is given in terms of a known form
factor and depends on the coupling constant of the heavy
(charmed) meson chiral perturbation theory Lagrangian. A measurement of the
above decay, in the aforementioned kinematic regime, can result in the
extraction of an experimental value for , accurate at the level of our
approximations, and give us a measure of the validity of approaches based on
chiral perturbation theory in studying similar processes.Comment: 17 pages, Latex, 2 embedded postscript figure
Inclusive J/psi and psi(2S) Production from B Decay in p p-bar Collisions
Using information on B-meson fragmentation functions from CERN LEP 1 and
adopting the nonrelativistic QCD factorization formalism proposed by Bodwin,
Braaten, and Lepage, we predict the transverse-momentum distribution of J/psi
mesons originating from the inclusive decays of b hadrons produced in p p-bar
collisions at the Fermilab Tevatron. We determine the relevant colour-octet
charmonium matrix elements from fits to CDF data on prompt charmonium
hadroproduction and to CLEO data on charmonium production from B-meson decay.
Our predictions are found to agree well with recent CDF and D0 data.Comment: 27 pages (Latex), 9 figures (Postscript
b-physics signals of the lightest CP-odd Higgs in the NMSSM at large tan beta
We investigate the low energy phenomenology of the lighter pseudoscalar
in the NMSSM. The mass can naturally be small due to a global
symmetry of the Higgs potential, which is only broken by trilinear
soft terms. The mass is further protected from renormalization group
effects in the large limit. We calculate the
amplitude at leading order in and work out the contributions to
rare , and radiative -decays and mixing. We obtain
constraints on the mass and couplings and show that masses down to
MeV are allowed. The -physics phenomenology of the NMSSM
differs from the MSSM in the appearance of sizeable renormalization effects
from neutral Higgses to the photon and gluon dipole operators and the breakdown
of the MSSM correlation between the branching ratio and
mixing. For masses above the tau threshold the
can be searched for in processes with branching ratios
\lsim 10^{-3}.Comment: 18 pages, 3 figures; references adde
Probing for the Charm Content of and Mesons
A slow bump exists in the inclusive spectrum,
while the softness of spectrum in decay
is in strong contrast with expectations from color octet mechanism. We propose
{\it intrinsic} charm as the explanation:the former is due to ,with three charm quarks in the final state; the latter is just a small
fraction of "jet" events, where the
slow moving system evolves into pairs. Experimental search
for these phenomena at B Factories and the Tevatron is strongly urged, as the
implications go beyond QCD.Comment: 4 pages, REVTEX, 10 eps figures included. Major revision with more
discussions on the rescattering background, and a reappraisal of the
Upsilon(1S) decay in the presence of intrinsic charm, leading to a change in
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