169 research outputs found

### On the eta(b) => J/psi J/psi decay

It has been argued long ago that eta(b) could be observed through the eta(b)
=> J/psi(=> mu+ mu-) J/psi(=> mu+ mu-) decay chain. Recent calculations
indicate that the width of eta(b) into two J/psi is almost three order of
magnitude smaller than the one into the D D*. We study the effects of final
state interactions due to the D D* intermediate state on the J/psi J/psi final
state. We find that the inclusion of this contribution may enhance the short
distance branching ratio of about two orders of magnitude.Comment: LaTeX, 5 pages, 2 figures. Contributed to QCD @ Work 2007:
International Workshop on Quantum Chromodynamics Theory and Experiment,
Martina Franca, Valle d'Itria, Italy, 16-20 Jun 200

### Non-Leptonic Two-Body Weak Decays of Charmed Mesons and CP-Violating Asymmetries

The non-leptonic two body decays of D mesons are studied in the framework of
an improved factorization approximation. The final state interaction effects
are taken into account assuming them dominated by nearby resonances. The
agreement with experimental data is quite good. CP-violating asymmetries are
predicted.Comment: 5 pages, LaTeX file. Talk given at 3rd German-Russian Workshop on
Progress in Heavy Quark Physics, Dubna, Russia, 20-22 May 199

### Final state interaction effects on the eta(b) => J/psi J/psi decay

We study the effects of final state interactions on the eta(b) => J/psi J/psi
decay. In particular, we discuss the effects of the annihilation of eta(b) into
two charmed meson and their rescattering into J/psi J/psi. We find that the
inclusion of this contribution may enhance the short-distance branching ratio
up to about 2 orders of magnitude.Comment: Parallel talk at ICHEP08, Philadelphia, USA, July 2008. 3 pages,
LaTeX, 3 eps figure

### A Geometric Picture For Fermion Masses

We describe a geometric picture for the pattern of fermion masses of the
three generations which is invariant with respect to the renormalization group
below the electroweak scale. Moreover, we predict the upper limit for the ratio
between the Dirac masses of the $\mu$ and $\tau$ neutrinos, $m_{\nu_{\mu}}/
m_{\nu_{\tau}} < (9.6 \pm 0.6) 10^{-3}$.Comment: 7 pages LATEX + 1 figur

### Non-Leptonic Two-Body Decays of Charmed Mesons and CP Violation

The nonleptonic two body decays of the $D$ and $D_s$ mesons represent a key subject to study possible effects of CP violation. The attention for these decay modes was triggered four years ago by the results of measurements of the difference between CP asymmetries in charged $KK$ and $\pi\pi$ final state, $\Delta a_{\rm CP}$. Although the measured $\Delta a_{\rm CP}$ is now compatible with zero the nonleptonic decays of charmed mesons into a pair of light mesons is an interesting subject for many reasons. Here we discuss phenomenological models to study the decays into two pseudoscalar mesons

### Long distance contributions to the eta_b => Jpsi Jpsi decay

It was argued long ago that eta_b could be observed through the eta_b =>
Jpsi(=> mu+ mu-) Jpsi(=> mu+ mu-) decay chain. Recent calculations indicate
that the width of eta_b into two Jpsi is almost 3 orders of magnitude smaller
than the one into the D bar D*. We study the effects of final-state
interactions due to the D bar D* intermediate state on the Jpsi Jpsi final
state. We find that the inclusion of this contribution may enhance the
short-distance branching ratio up to about 2 orders of magnitude.Comment: 4 pages, 3 figures. The estimate of the dispersive contribution was
added. Typos corrected. To be published in Phys. Rev.

### On $SU(3)_{F}$ Breaking through Final State Interactions and CP Asymmetries in $D\to P P$ Decays

We analyse $D$ decays to two pseudoscalars $(\pi,K)$ assuming the dominant
source of $\mathrm{SU}(3)_F$ breaking lies in final state interactions. We
obtain an excellent agreement with experimental data and are able to predict CP
violation in several channels based on current data on branching ratios and
$\Delta \mathrm{A_{CP}}$. We also make predictions for $\delta_{K\pi}$ and the
branching fraction for the decay $D_s^+\to K^+K_L$.Comment: 21 pages. Updated with the 2019 measurement of $\Delta
\mathrm{A_{CP}}$ from LHC

### Semileptonic and nonleptonic decays of Bc

Using our relativistic constituent quark model we present results on the
exclusive nonleptonic and semileptonic decays of the Bc-meson. The nonleptonic
decays are studied in the framework of the factorization approximation. We
calculate the branching ratios for a large set of exclusive nonleptonic and
semileptonic decays of the Bc-meson and compare our results with the results of
other models.Comment: 4 pages, proceeding of the talk given by Pietro Santorelli at IFAE
2006, Pavia, 19-21 Aprile 200

### Final state interactions for B => VV charmless decays

We estimate final state interactions in the B-meson decays into two light
vector mesons by the Regge model. We consider Pomeron exchange and charmed
Regge trajectories that can relate intermediate charmed particles to the final
state. The Regge poles have various helicity-flip residues, which allows a
change from the longitudinal to transverse polarization. In this way a
significant reduction of the longitudinal polarization fraction can be
produced. In the factorization approximation we find agreement with recent data
from the BaBar and Belle collaborations in the B => K* phi decay channel, as a
result of an appropriate choice of semileptonic form factors and Regge
exchanges. On the other hand, data for the K* rho decay channels appear more
elusive. The soft effects discussed in the present paper are based on a model
of Regge trajectories that is shown to reproduce correctly in the non-charmed
case the Regge phenomenology of light mesons.Comment: 10 pages, 6 figure

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