A study of the D+ K- + +

Author(s)

Patricia Camargo Magalhães

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Física (IF/SBI)
• Defense date: 2014-05-16

Examining board members

Manoel Roberto Robilotta; Gustavo Alberto Burdman; Airton Deppman; Ignácio Alfonso de Bediaga e Hickman; Adriano Antonio Natale

• Advisor: Manoel Roberto Robilotta

Abstract

This study describer the D+ K++ decay. We developed two models for complementary issues of the main dynamic process in this system: the weak vertex, where the transition c Ws takes place, and the interactions between the three mesons in the final state. This work was motivated by important experimental results for D+ K++ decay in which the S wave phase for a K pair in the final state does not agree with the phase from K free scattering amplitude, which is here named phase puzzle. In the first model, the interaction in the final states are treated as successive rescattering between K pairs, and the weak vertex is approximated as structureless functions. The K amplitude is a fundamental ingredient and is calculated using an effective quiral lagrangian with resonances. The decay amplitudes were solved perturbatively up to second order in K rescattering for all the three topologies that can contribute. The results for the first model show the importance of final state interactions where the proper three body effect are essential for the good description of experimental data, obtained from one of the topologies. In the second model, the weak vertex is calculated using an effective theory that couples the light SU(3) sector to the charm sector and describes all interactions, strong and weak, between the two sectors. This model includes the correct momentum dependences at verticies and contain mainly three improvements: (i) correctly incorporates the P- wave momentum structure in the vertex through the use of V A currents; (ii) includes V DK vertex parametrized by monopoles form factors; and (iii) includes in the V vertex the W transition intermediated by a r resonance, which gives rise to a strong form factor. The results for the second model show that the form factors effects on D K vertex are small and more important at higher energy. The inclusion of the meson as a resonance is very significant and dislocates the phase shift from zero to 90o at threshold, which explains the qualitative experimental data behaviour in the same region. (AU)