Amplitude Analysis of the Decay $$D^+ \to K_s \pi^- \pi^+ \pi^+$$ in the {FOCUS} Experiment (in Portuguese)
- Rio de Janeiro, Pont. U. Catol.
This thesis is devoted to the study of the decay D+ → KS π-π+π+ with data collected from the FOCUS experiment, at Fermilab. The final state composed of 4 pseudo-scalars can be produced through a number of resonant sub-structures. The purpose of this analysis is to find the contributing intermediate states by measuring their relative strengths and phases. For that, the Amplitude Analysis formalism is used, with the so-called Isobar Model. The decay dynamics is described through a function which has the features of the contributing channels (functional forms of the resonances, angular distribution, etc.) and which domain is a phase space determined by 5 invariants (due to the kinematical constraints of a 4-body spinless decay). The data sample is thus final to this function. Our results show a dominant contribution of the axial-vector meson a1(1260) (52%), followed by the K1(1400) axial-vector (34%). Moreover, the model presents a contribution from the σ meson (about 8% as a1(σπ)KS and σKS π) and a significant contribution from the scalar κ-. The κ state has been reported in its neutral mode in other charm decays but not is its charged mode. We find no significant contribution from the direct 4-body decay (non-resonant). This work adds to the effort in the understanding of the strong-interaction dynamics at low energies, which in recent years have been receiving an important contribution from charm meson physics.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), High Energy Physics (HEP)
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 1436756
- Report Number(s):
- PUC-RIO-0220955-CA; FERMILAB-THESIS-2007-90; 926225
- Country of Publication:
- United States
- Language:
- Portuguese
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