Related papers: Odd-Parity Nucleon Electromagnetic Transitions in …
The recently-introduced Parity Expanded Variational Analysis (PEVA) technique allows for the isolation of baryon eigenstates on the lattice at finite momentum free from opposite-parity contamination. We find that this technique introduces a…
Variational analysis techniques in lattice QCD are powerful tools that give access to the excited state spectrum of QCD. At zero momentum, these techniques are well established and can cleanly isolate energy eigenstates of either positive…
First principles calculations of the form factors of baryon excitations are now becoming accessible through advances in Lattice QCD techniques. In this paper, we explore the utility of the parity-expanded variational analysis (PEVA)…
Variational analysis techniques in lattice QCD are powerful tools that give access to the full spectrum of QCD. At zero momentum, these techniques are well established and can cleanly isolate energy eigenstates of either positive or…
The recently-introduced Parity Expanded Variational Analysis (PEVA) technique allows for the isolation of baryon eigenstates at finite momentum free from opposite-parity contamination. In this paper, we establish the formalism for computing…
In recent years, the use of variational analysis techniques in lattice QCD has been demonstrated to be successful in the investigation of the rest-mass spectrum of many hadrons. However, due to parity-mixing, more care must be taken for…
The world's first examination of the odd-parity nucleon spectrum at light quark masses in 2+1 flavor lattice QCD is presented. Configurations generated by the PACS-CS collaboration and made available through the ILDG are used, with the…
We report a direct lattice QCD calculation of the strange nucleon electromagnetic form factors $G_E^s$ and $G_M^s$ in the kinematic range $0 \leq Q^2 \lesssim 1.2\: {\rm GeV}^2$. For the first time, both $G_E^s$ and $G_M^s$ are shown to be…
The long-range, parity-odd nucleon interaction generated by single pion exchange is captured in the parity-odd pion-nucleon coupling $h^1_\pi$. Its calculation in lattice QCD requires the evaluation of 4-quark operator nucleon 3-point…
The recent parity-violating $ep$ forward-scattering elastic asymmetry data from Jefferson Lab (HAPPEx and G0), when combined with the $\nu p$ elastic cross section data from Brookhaven (E734), permit an extraction of the strangeness…
We report new measurements of the parity-violating asymmetry A_PV in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with <theta_lab>~6.0 degrees. The 4He result is A_PV = (+6.40 +/- 0.23 (stat) +/- 0.12 (syst)) x10^-6.…
This brief review focuses on the low-lying even- and odd-parity excitations of the nucleon obtained in recent lattice QCD calculations. Commencing with a survey of the 2014-15 literature we'll see that results for the first even-parity…
We present the strange electromagnetic form factors of the nucleon using lattice QCD with $N_f=2+1+1$ twisted mass clover-improved fermions and quark masses tuned to their physical values. Using four ensembles with lattice spacings of…
We present the nucleon strange electromagnetic form factors using four lattice QCD ensembles with $N_f=2+1+1$ twisted mass clover-improved fermions and quark masses tuned to approximately their physical values. The four ensembles have…
Positive-parity spin-1/2 excitations of the nucleon are explored in lattice QCD. The variational method is used in this investigation and several correlation matrices are employed. As our focus is on the utility and methodology of the…
Recent experimental and theoretical advancements have led to significant progress in our understanding of the electromagnetic structure of nucleons ($N$), nucleon excitations ($N^\ast$), and other baryons. These breakthroughs have been made…
It is imperative that lattice QCD serve to develop our understanding of hadron structure and, where possible, to guide the interpretation of experimental data. There is now a great deal of effort directed at the calculation of the…
The simplest models might describe the nucleon as 3 light quarks, but this description would be incomplete without inclusion of the sea of glue and q-qbar pairs which binds it. Early indications of a particularly large contribution from…
The contribution of the strange-quark current to the electromagnetic form factors of the nucleon is studied using lattice QCD. The strange current matrix elements from our lattice calculation are analyzed in two different ways, the…
We carry out a feasibility study toward a lattice QCD calculation of the neutron electric dipole moment (NEDM) in the presence of the $\theta$ term using two different approaches. In the first method, we calculate the CP-odd electromagnetic…