arXiv subjects
Publications and source records attributed to Alberto Reis.
The FOCUS photoproduction experiment took data in the ninenties and produced a wealth of results in charm physics. Some of the studies were seminal for contemporary experiments, and even paved the way for the technology of many charm and beauty analysis tools.
This paper is focused on two issues: the Kπspectrum near threshold - the kappa problem -, and the piπspectrum between 1.2 and 1.5 GeV/(c^2) -- the f_0(1370) problem. Both problems will be analysed from the perspective of the $D$ meson decays, with some additional information from $τ$ and B decays.
In the past few years the B-factories became unexpected players in the scalar mesons business: in order to access the CP violation effects, it is necessary to handle the dynamics of the strong interaction between the final state hadrons. A number of large statistics studies heavy flavor decays involving a scalar component have been performed recently by Belle and BaBar, who have joined CLEOc, BES, E791 and FOCUS in the effort to understand the physics of the scalar mesons. In this talk, the most recent results from these experiments will be reviewed, with emphasis on the low energy $Kπ$ system and on the f0(1370).
This work is a direct and model-independent measurement of the low mass $\pi^+\pi^-$ phase motion in the $D^+ \to \pi^-\pi^+\pi^+$ decay. The results show a strong phase variation, compatible with an isoscalar $\sigma(500)$ meson. This result confirms the previous Fermilab E791 result which found evidence for the existence of this scalar particle using a full Dalitz-plot analysis.
Weak decays of charm mesons has been used for studies of light quark spectroscopy, with particular emphasis on the J^{PC}=0^{++} states. Recent results on light scalars are summarized and some conceptual issues are discussed, especially the relation between charm decays and hadronic production.