Banca de DEFESA: ALINE GRAMACHO FAVERO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : ALINE GRAMACHO FAVERO
DATA : 16/05/2019
HORA: 15:00
LOCAL: Instituto de Física da Universidade Federal da Bahia
TÍTULO:

Hadronic spectroscopy via QCD no gauge of
Coulomb

PALAVRAS-CHAVES:

Espectroscopia hadrônica, QCD ,gauge de Coulomb

PÁGINAS: 95
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

Having predicted several physical phenomena, the Standard Model of particle physics
is now a well-established theory, in agreement with much of the results
experiments. But despite being the best description available today of the subatomic world,
it is a model still under construction: the strong interaction sector, for example,
is still incomplete, and the search for unconventional hadronic states is intense.
The existence and structure of these unconventional particles is one of the few
issues still open in the Standard Model. These states, allowed by Chromodynamics
(Quantum Chromodynamics, or QCD), are those that do not
fit the usual classification of mesons (qq) and baryons (qqq), such as glueballs,
hybrid states, tetraquarks, pentaquarks, and hadrons with non-quantum numbers.
conventional.
Due to the complexity of the theory of strong interactions, theoretical
Exotic hawthrons involve several methods. Asymptotic freedom allows, at high
energy scales, the QCD is treated perturbatively; in low energies, there are
different alternatives, such as the Nambu-Jona-Lasinio model, NRQCD, Lattice
QCD and effective theories. The model used in this work is based on a Hamiltonian
Effect of QCD on Coulomb gauge, and has applications in meson studies [1-5],
glueballs [6], exotic states [7] and in the study of the breaking of chiral symmetry [8,9].
Starting from the exact Hamiltonian of QCD in the Coulomb gauge, we
an effective Hamiltonian, in which we replace the kernel of Coulomb interaction with a
effective confinement potential similar to Cornell's potential; how our focus
is the study of mesons, neglecting the gluonic sector, and we replace the quarkglúon interaction
by a transverse hyperfine potential. To this effective hamiltonian, we then apply
techniques of many bodies in order to obtain their approximately diagonalized form:
state of vacuum, we apply a transformation of Bogoliubov-Valatin or BCS (Bardeen-
Cooper-Schrieffer), and to the excited states, the TDA (Tamm-Dancoff) and RPA
(Random Phase Approximation). Of the latter two methods, only RPA is capable of
describe the chiral symmetry break. This model has as one of its advantages the
minimum number of input parameters - the masses of the current quarks and two
constants related to potentials -, in addition to the fact that their fundamental degrees of freedom
quarkionic degrees of freedom, when most of the models
effectively work on hadronic degrees of freedom.
Previous work has already embraced Cornell's potential as modified [1], as well as the
hyperfine potential [1, 7]. In the present work, we extend previous studies to mesons
composed of quarks of different flavors, and compute the spectra of mesons
pseudo-scalar, vector and pseudovectoral in the light quarks, foreign,
charmón and botomônio.
The notation adopted throughout this work is detailed in appendix A. The chapter
2 is dedicated to the construction of the theoretical basis necessary for the development of the model
Effective: We present the Standard Model of particle physics, followed by the
quarks and their classification of hadrons. Next, we describe the mathematical framework
behind the Standard Model, in which the principle of gauge invariance acquires
big importance. As a natural sequence, we explore this principle further,
showing the process of construction of abelian and non-abelian gauge theories, passing
Quantum Electrodynamics (QED) and finalizing with a description of QCD, the
our field of study. In the actual model with which we work, similar quantities
those that started in the QED were used, and these were introduced in this chapter.
Chapter 3 is dedicated to obtaining the exact Hamiltonian of QCD in Coulomb gauge.
Starting from the Lagrangian of QCD obtained in Chapter 2, we apply to it successive
transformations of gauge - first, we pass to the gauge deWeyl, and then to the gauge
of Coulomb -, finally obtaining the desired Hamiltonian. Intermediary parts of the account
contained in Appendix B.

Finally, in chapter 4, starting from the exact Hamiltonian, we construct the effective model
of QCD in the Coulomb gauge for the quarkionic sector. Following, we turn to the
application of the techniques of many bodies in order to obtain approximately diagonal shapes
of the Hamiltonian. Before diagonalizing it, however, we apply a BCS rotation to the
base of our Fock space, moving to a base of effective mass quasiparticles
constituents. In order to determine the fundamental state of this approximation, we solve
the mass gap equation, which calculations are detailed in Appendix C. To determine
the excited states, we use the TDA and RPA methods. Obtaining the equation
TDA is detailed in appendix D. In these final sections, we
mesons introduced in Chapter 2, and we obtained the kernels for the pseudo-scalar cases,
vector and pseudovectoral, for quarks of the same and different flavors; the RPA method was
applied only to the pseudo-scalar case. With the kernels in hand, the last session was
dedicated to an analysis of the numerical results, where we present the different masses obtained
in the resolution of the gap equation, as well as the spectra obtained for the different
quarkionic sectors. Finally, we analyze the contribution of hyperfine potential as well as
such as the importance of chiral symmetry.

MEMBROS DA BANCA:
Externo à Instituição - FERNANDO SILVEIRA NAVARRA - USP
Presidente - 1551342 - LUCIANO MELO ABREU
Interno - 2060414 - MARIO CEZAR FERREIRA GOMES BERTIN