https://doi.org/10.1140/epjc/s10052-009-1028-9
Regular Article - Theoretical Physics
Penguins with charm and quark–hadron duality
1
Institut für Theoretische Physik E, RWTH Aachen University, 52056, Aachen, Germany
2
CERN Theory Department, 1211, Genève, Switzerland
3
Fakultät für Physik, Arnold Sommerfeld Center for Theoretical Physics, Ludwig-Maximilians-Universität München, 80333, München, Germany
4
Institut für Physik (THEP), Johannes Gutenberg-Universität, 55099, Mainz, Germany
5
School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK
* e-mail: gerhard.buchalla@lmu.de
Received:
4
March
2009
Revised:
23
March
2009
Published online:
8
April
2009
The integrated branching fraction of the process B→X
s
l
+
l
− is dominated by resonance background from narrow charmonium states, such as B→X
s
ψ→X
s
l
+
l
−, which exceeds the non-resonant charm-loop contribution by two orders of magnitude. The origin of this fact is discussed in view of the general expectation of quark–hadron duality. The situation in B→X
s
l
+
l
− is contrasted with charm-penguin amplitudes in two-body hadronic B decays of the type B→π
π, for which it is demonstrated that resonance effects and the potentially non-perturbative
threshold region do not invalidate the standard picture of QCD factorization. This holds irrespective of whether the charm quark is treated as a light or a heavy quark.
© Springer-Verlag, 2009