S. Fajfer. based on hep-ph/0308100, Phys. Rev. D 68 (2003) 094012 by. Motivation. Hidden strangeness FSI. Framework. Comparison with the experimental data. Conclusions. Motivation. a ) The decay rate :. PDG result. It has been suggested by.
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based on hep-ph/0308100, Phys. Rev. D 68 (2003) 094012 by
Hidden strangeness FSI
a) The decay rate:
It has been suggested by
that this observation is a clean signature of the annihilation decay of .
The factorization approximation gives zero for the decay amplitude due to the isospin and G parity .
The knowledge of the annihilation contribution is very important for the
We argue that the experimental value for the transition
can be accommodated by considering ONLY color suppressed spectator
decay with subsequent final state interactions (FSI).
This leaves little room for unambiguous study of the annihilation effects from the
b) the decay rate
A scan through PDG book reveals that there are no resonances with
This indicates the enhancement of the annihilation contribution:
The PDG upper bound for the
Usingthe factorization approximation for the weak vertex we obtain an estimate for the size of annihilation contribution:
We resort following approximations:
For the matrix elements between Ds and light vector and pseudoscalar states we
use standard decomposition
does not satisfactorily reproduce experimental result
We have checked that factorization approximation works well in the case
Note that the loop contributions coming from hidden strangeness states are finite!
This result contains the amplitudes for the transition
calculated within factorization approach.
If one uses experimental input to rescale the amplitudes, the prediction is
Adding the FSI contribution with maximal annihilation contribution with
alternating signs gives a fairly large interval:
If instead of double/single pole parametrization of the form factors, one uses standard single pole parametrization the loop integrals give logarithmic divergence.
In this case the real part of amplitudes are cut – off dependent, while imaginary parts are not.
By taking the cut-off parameter to be close to the charm meson mass scale we obtain
that the amplitudes are very close to the ones obtained in the case of double/single pole
The numerical results are rather stable on the small variation of the cut-off.
FSI we are considering is not leading contribution.
This decay can proceed through the spectator mechanism directly.
The use of factorization approximation leads to
in very good agreement with the experimental result .
The inclusion of FSI reduces rate from 4% to 3.6%!
shows that the S-wave component has dominant