418 research outputs found
B0bar decays to D(*)0 eta and D(*)0 eta'
We consider the hadronic B decays B0bar -> D0 eta, B0bar -> D*0 eta, B0bar ->
D0 eta', B0bar -> D*0 eta' in the framework of a quark-flavour basis and
factorization. The formalism allows to compute the decays to the eta meson and
to relate them to those of the eta'. Measuring the branching ratios of these
processes may shed light on the nature of the eta-eta' mixing. On the
experimental side, only upper limits on the branching ratios are known at
present.Comment: 12 pages, 2 figures, 2 tables (LaTeX, revtex), minor revision: note
added at the end concerning new data and few reference
B->rho pi decays, resonant and nonresonant contributions
We point out that a new contribution to B decays to three pions is relevant
in explaining recent data from the CLEO and BABAR collaborations, in particular
the results on quasi-two-body decays via a rho meson. We also discuss the
relevance of these contribution to the measurement of CP violations.Comment: 5 pages, 2 figures, few references and minor comments adde
On the mass of the Ds(0+,1+) system
In this note we discuss a determination for the mass of the Ds(0+,1+) system
recently discovered by the BaBar, CLEO II and Belle Collaborations. The value
of the mass is derived by making explicit the prediction obtained in a
quark-meson model prior to the discovery of these states.Comment: 3 pages, revte
The exclusive B_s -> phi mu+ mu- process in a constituent quark model
We consider the exclusive B_s -> phi mu+ mu- process in the standard model
using a constituent quark loop model approach together with a simple
parameterization of the quark dynamics. The model allows to compute the decay
form factors and therefore can give predictions for the decay rates, the
invariant mass spectra and the asymmetries. This process is suppressed in the
standard model but can be enhanced if new physics beyond the standard model is
present, such as flavor-violating supersymmetric models. It constitutes
therefore an interesting precision test of the standard model at forthcoming
experiments.Comment: 17 pages, 6 figures, 5 tables, LaTeX; minor changes to the
introduction, table III and figure 3. Few references adde
The s-sbar and K-Kbar nature of f_0(980) in D_s decays
We examine the D_s -> f_0(980) pi amplitude through a constituent quark-meson
model, incorporating heavy quark and chiral symmetries, finding a good
agreement with the recent E791 data analysis of D_s -> 3pi via f_0(980). The
f_0(980) resonance is considered at the moment of production as an s sbar
state, later evolving to a superposition of mainly s sbar and K Kbar. The
analysis is also extended to the more frequent process D_s -> phi pi.Comment: 8 pages, 5 figure
Semileptonic decays of , , and
Stimulated by recent observations of the excited bottom-strange mesons
and , we calculate the semileptonic decays , which is relevant for the exploration of the
potential of searching these semileptonic decays in experiment.Comment: 11 pages, 3 figures, 9 tables. More discussion added, some
descriptions changed. The version to appear in EPJ
Power law in a gauge-invariant cut-off regularisation
We study one-loop quantum corrections of a compactified Abelian 5d gauge
field theory. We use a cut-off regularisation procedure which respects the
symmetries of the model, i.e. gauge invariance, exhibits the expected
power-like divergences and therefore allows the derivation of power-law
behavior of the effective 4d gauge coupling in a coherent manner.Comment: 5 pages, 1 figure, 5 graphs, few references added, to appear in
Phys.Rev. Rapid Communication
Analysis of Narrow s-channel Resonances at Lepton Colliders
The procedures for studying a single narrow s-channel resonance or nearly
degenerate resonances at a lepton collider, especially a muon collider, are
discussed. In particular, we examine four methods for determining the
parameters of a narrow s-channel resonance: scanning the resonance, measuring
the convoluted cross section, measuring the Breit-Wigner area, and sitting on
the resonance while varying the beam energy resolution. This latter procedure
is new and appears to be potentially very powerful. Our focus is on computing
the errors in resonance parameters resulting from uncertainty in the beam
energy spread. Means for minimizing these errors are discussed. The discussion
is applied to the examples of a light SM-Higgs, of the lightest pseudogoldstone
boson of strong electroweak breaking, and of the two spin-1 resonances of the
Degenerate BESS model (assuming that the beam energy spread is less than their
mass splitting). We also examine the most effective procedures for nearly
degenerate resonances, and apply these to the case of Degenerate BESS
resonances with mass splitting of order the beam energy spread.Comment: 63 pages, 16 figure
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