Related papers: Nucleon Excited State Wave Functions from Lattice …
Using a new quark-field construction algorithm and a large variational basis of operators, we extract a highly excited isovector meson spectrum on dynamical anisotropic lattices. We show how carefully constructed operators can be used to…
We study charge excitation spectra in the two-dimensional $t$-$J$ model on a square lattice to explore a charge-order tendency recently found in electron-doped cuprates around the carrier density 0.15. The static susceptibility of $d$-wave…
This thesis deals with the study of baryon spectra in the context of the $1/N_c$ expansion. The standard tool to study baryon properties is the constituent quark model. The results are naturally model dependent. The $1/N_c$ expansion…
We report on single-object spectroscopic studies of a characteristic set of three resonances which appear in GaAlAs/AlAs quantum dot structures. The experiments included the photoluminescence (PL) and photoluminescence excitation (PLE)…
The hyperfine interactions of the constituent quark model provide a natural explanation for many nucleon properties, including the Delta-N splitting, the charge radius of the neutron, and the observation that the proton's quark distribution…
A potential model for four interacting quarks is constructed in SU(2) from six basis states -- the three partitions into quark pairs, where the gluon field is either in its ground state or first excited state. With four independent…
We discuss the quantum mechanics of coalescence of quark-antiquark pairs into mesons using a non-relativistic quark model. We derive the coalescence probabilities assuming a harmonic oscillator potential and generic Gaussian wave packet…
Lattice QCD has matured to a degree where it is now possible to study excited hadrons as they truly appear in nature, as short-lived resonant enhancements decaying into multiple possible final states. Through variational analysis of…
We present the ground and excited state spectra of doubly charmed baryons from lattice QCD with dynamical quark fields. Calculations are performed on anisotropic lattices of size 16^3 X 128, with inverse spacing in temporal direction 1/a_t…
We present results from our recent lattice QCD study of $N\pi$ scattering in the positive-parity nucleon channel, where the puzzling Roper resonance $N^*(1440)$ resides in experiment. Using a variety of hadron operators, that include…
Interpolating fields, used to excite hadrons from the QCD vacuum in nonperturbative field-theoretic investigations of hadron properties, are explored with an emphasis on unconventional nucleon interpolators. The QCD continuum model for…
We determine the nucleon-sigma terms from lattice QCD. We find that the dominant excited state contamination in the nucleon three-point function with a scalar current is due to the transition between the nucleon and a S-wave scattering…
Analytical formulas for the excitation energies as well as for the electric quadrupole reduced transition probabilities in the ground, beta and gamma bands were derived within the coherent state model for the near vibrational and well…
Results of hadron spectroscopy with two dynamical mass-degenerate chirally improved quarks are presented. Three ensembles with pion masses of 322(5), 470(4) and 525(7) MeV, lattices of size 16^3 \times 32, and lattice spacings close to 0.15…
We study the spectrum of the even parity excitations of the nucleon in quenched lattice QCD. We extend our earlier analysis by including an expanded basis of nucleon interpolating fields, increasing the physical size of the lattice,…
Lattice calculations could boost our understanding of Deep Inelastic Scattering by evaluating moments of the Nucleon Structure Functions. To this end we study the product of electromagnetic currents between quark states. The Operator…
Recent advances in the study of excited nucleons are discussed. Much of the progress has been achieved due to the availability of high precision meson production data in the photoproduction and electroproduction sectors, the development of…
Employing the maximum entropy method we extract the spectral functions from meson correlators at four lattice spacings in quenched QCD with the Wilson quark action. We confirm that the masses and decay constants, obtained from the position…
We perform a high-statistics precision calculation of nucleon matrix elements using an open sink method allowing us to explore a wide range of sink-source time separations. In this way the influence of excited states of nucleon matrix…
A description of the nucleon and Roper resonance in a quark-diquark approach is presented. We show that two states with the quantum number of the nucleon can appear in the ground state of the spatial configuration, when there are two types…