Amy Nicholson
YOU?
Author Swipe
View article: Lattice QCD study of πΣ-K¯N scattering and the Λ(1405) resonance
Lattice QCD study of πΣ-K¯N scattering and the Λ(1405) resonance Open
A lattice QCD computation of the coupled channel πΣ–K¯N scattering amplitudes in the Λ(1405) region is detailed. Results are obtained using a single ensemble of gauge field configurations with Nf=2+1 dynamical quark flavors and mπ≈200 MeV …
View article: The Λ(1405) pole structure from Lattice QCD: A coupled-channel πΣ − KN study
The Λ(1405) pole structure from Lattice QCD: A coupled-channel πΣ − KN study Open
This report summarizes results of the first lattice QCD calculation of coupled-channel πΣ − K ¯ N scattering in the Λ(1405) region. This study was carried out using a single CLS ensemble with a heavier-than-physical pion mass m π ≈ 200 MeV…
View article: The Λ(1405) pole structure from Lattice QCD: A coupled-channel <i>π</i>Σ − <i>K</i><i>N</i> study
The Λ(1405) pole structure from Lattice QCD: A coupled-channel <i>π</i>Σ − <i>K</i><i>N</i> study Open
This report summarizes results of the first lattice QCD calculation of coupled-channel πΣ − K ¯ N scattering in the Λ(1405) region. This study was carried out using a single CLS ensemble with a heavier-than-physical pion mass m π ≈ 200 MeV…
View article: Lattice QCD studies of the $\Delta$ baryon resonance and the $K_0^\ast(700)$ and $a_0(980)$ meson resonances: the role of exotic operators in determining the finite-volume spectrum
Lattice QCD studies of the $\Delta$ baryon resonance and the $K_0^\ast(700)$ and $a_0(980)$ meson resonances: the role of exotic operators in determining the finite-volume spectrum Open
Studies of the $\\Delta$ baryon resonance and the $K_0^\\ast(700)$ and $a_0(980)$ meson resonances using $N_f=2+1$ lattice QCD for pion masses near 200 MeV are presented. The $s$-wave scattering lengths for both the $I=1/2$ $N \\pi$ and $I…
View article: Lattice QCD studies of the $Δ$ baryon resonance and the $K_0^\ast(700)$ and $a_0(980)$ meson resonances: the role of exotic operators in determining the finite-volume spectrum
Lattice QCD studies of the $Δ$ baryon resonance and the $K_0^\ast(700)$ and $a_0(980)$ meson resonances: the role of exotic operators in determining the finite-volume spectrum Open
Studies of the $Δ$ baryon resonance and the $K_0^\ast(700)$ and $a_0(980)$ meson resonances using $N_f=2+1$ lattice QCD for pion masses near 200 MeV are presented. The $s$-wave scattering lengths for both the $I=1/2$ $N π$ and $I=3/2$ $N π…
View article: The $Λ(1405)$ from Lattice QCD: Determining the Finite-volume Spectra
The $Λ(1405)$ from Lattice QCD: Determining the Finite-volume Spectra Open
This work presents technical details of determining the finite-volume energy spectra for the scattering amplitude of the coupled-channel $πΣ- \bar{K}N$ from lattice QCD data. The importance of reliably extracting such spectra lies in the c…
View article: Low-lying baryon resonances from lattice QCD
Low-lying baryon resonances from lattice QCD Open
Recent results studying the masses and widths of low-lying baryon resonances in lattice QCD are presented. The $S$-wave $Nπ$ scattering lengths for both total isospins $I = 1/2$ and $I = 3/2$ are inferred from the finite-volume spectrum be…
View article: Lattice QCD study of $πΣ-\bar{K}N$ scattering and the $Λ(1405)$ resonance
Lattice QCD study of $πΣ-\bar{K}N$ scattering and the $Λ(1405)$ resonance Open
A lattice QCD computation of the coupled channel $πΣ-\bar{K}N$ scattering amplitudes in the $Λ(1405)$ region is detailed. Results are obtained using a single ensemble of gauge field configurations with $N_{\rm f} = 2+1$ dynamical quark fla…
View article: Two-pole nature of the $Λ(1405)$ from lattice QCD
Two-pole nature of the $Λ(1405)$ from lattice QCD Open
This letter presents the first lattice QCD computation of the coupled channel $πΣ-\bar{K}N$ scattering amplitudes at energies near $1405\,{\rm MeV}$. These amplitudes contain the resonance $Λ(1405)$ with strangeness $S=-1$ and isospin, spi…
View article: Massive and massless modes of the triplet phase of neutron matter
Massive and massless modes of the triplet phase of neutron matter Open
Neutron matter at densities on the order of the nuclear saturation density is believed to have neutrons paired in the P23 channel. We study the low-lying modes of this phase and find two massless modes (angulons), resulting from the sponta…
View article: Elucidating the sign problem through noise distributions
Elucidating the sign problem through noise distributions Open
Due to the presence of light pions in the theory, lattice QCD at finite densities suffers from issues with noise in both grand canonical and canonical formulations. We study two different formulations of the Nambu-Jona-Lasinio model reduce…
View article: Listening to noise
Listening to noise Open
We show how sign problems in simulations of many-body systems can manifest themselves in the form of heavy-tailed correlator distributions, similar to what is seen in electron propagation through disordered media. We propose an alternative…
View article: Low energy scattering phase shifts for meson-baryon systems
Low energy scattering phase shifts for meson-baryon systems Open
In this work, we calculate meson-baryon scattering phase shifts in four channels using lattice QCD methods. From a set of calculations at four volumes, corresponding to spatial sizes of 2, 2.5, 3, and 4 fm, and a pion mass of mπ∼390 MeV, w…
View article: A per-cent-level determination of the nucleon axial coupling from quantum chromodynamics
A per-cent-level determination of the nucleon axial coupling from quantum chromodynamics Open
The axial coupling of the nucleon, g A, is the strength of its coupling to the weak axial current of the standard model of particle physics, in much the same way as the electric charge is the strength of the coupling to the electromagnetic…
View article: Sign problems, noise, and chiral symmetry breaking in a QCD-like theory
Sign problems, noise, and chiral symmetry breaking in a QCD-like theory Open
The Nambu-Jona-Lasinio model reduced to 2+1 dimensions has two different path integral formulations: at finite chemical potential one formulation has a severe sign problem similar to that found in QCD, while the other does not. At large N,…
View article: Baryon masses at nonzero isospin/kaon density
Baryon masses at nonzero isospin/kaon density Open
We present a lattice QCD calculation of the ground-state energy shifts of various baryons in a medium of pions or kaons at a single value of the quark mass corresponding to a pion mass of mπ∼390 MeV and a kaon mass of mK∼540 MeV, and in a …
View article: Nuclear parity violation from lattice QCD
Nuclear parity violation from lattice QCD Open
The electroweak interaction at the level of quarks and gluons are well understood from precision measurements in high energy collider experiments. Relating these fundamental parameters to Hadronic Parity Violation in nuclei however remains…
View article: Baryon properties in meson mediums from lattice QCD
Baryon properties in meson mediums from lattice QCD Open
We present results for the ground-state mass shifts of octet baryons due to the presence of a medium of pions or kaons from a lattice QCD calculation performed at a single value of the quark mass, corresponding to a pion mass of mpΠ ∼390 M…
View article: A new approach for studying large numbers of fermions in the unitary regime
A new approach for studying large numbers of fermions in the unitary regime Open
A novel lattice approach is presented for studying systems comprising a large number of interacting nonrelativistic fermions. The construction is ideally suited for numerical study of fermions near unitarity-a strongly coupled regime corre…
View article: Reducing baryon noise in lattice QCD through partial quenching
Reducing baryon noise in lattice QCD through partial quenching Open
The study of nuclear physics using lattice QCD is hindered by an exponentially large signal-to-noise problem that is conventionally alleviated by raising the quark masses to unphysically high values. We propose a novel form of partial quen…
View article: Detailed analysis of excited-state systematics in a lattice QCD calculation of gA
Detailed analysis of excited-state systematics in a lattice QCD calculation of gA Open
Excited state contamination remains one of the most challenging sources of systematic uncertainty to control in lattice QCD calculations of nucleon matrix elements and form factors: early time separations are contaminated by excited states…
View article: Progress in multibaryon spectroscopy
Progress in multibaryon spectroscopy Open
Anchoring the nuclear interaction in QCD is a long-outstanding problem in nuclear physics. While the lattice community has made enormous progress in mesonic physics and single nucleon physics, continuum-limit physical-point multi-nucleon p…
View article: Noise, sign problems, and statistics
Noise, sign problems, and statistics Open
We show how sign problems in simulations of many-body systems can manifest themselves in the form of heavy-tailed correlator distributions, similar to what is seen in electron propagation through disordered media. We propose an alternative…
View article: Elastic nucleon-pion scattering at $m_π$ = 200 MeV from lattice QCD
Elastic nucleon-pion scattering at $m_π$ = 200 MeV from lattice QCD Open
Elastic nucleon-pion scattering amplitudes are computed using lattice QCD on a single ensemble of gauge field configurations with $N_f = 2+1$ dynamical quark flavors and $m_π$ = 200 MeV. The s-wave scattering lengths with both total isospi…
View article: FLAG Review 2021
FLAG Review 2021 Open
We review lattice results related to pion, kaon, D -meson, B -meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of th…
View article: Report of the Snowmass 2021 Topical Group on Lattice Gauge Theory
Report of the Snowmass 2021 Topical Group on Lattice Gauge Theory Open
Lattice gauge theory continues to be a powerful theoretical and computational approach to simulating strongly interacting quantum field theories, whose applications permeate almost all disciplines of modern-day research in High-Energy Phys…
View article: Integrating de novo and inherited variants in 42,607 autism cases identifies mutations in new moderate-risk genes
Integrating de novo and inherited variants in 42,607 autism cases identifies mutations in new moderate-risk genes Open
To capture the full spectrum of genetic risk for autism, we performed a two-stage analysis of rare de novo and inherited coding variants in 42,607 autism cases, including 35,130 new cases recruited online by SPARK. We identified 60 genes w…
View article: Toward a resolution of the NN controversy
Toward a resolution of the NN controversy Open
Lattice QCD calculations of two-nucleon interactions have been underway for about a decade, but still haven't reached the pion mass regime necessary for matching onto effective field theories and extrapolating to the physical point. Furthe…
View article: Progress on Meson-Baryon Scattering
Progress on Meson-Baryon Scattering Open
Progress in computing various meson-baryon scattering amplitudes is presented on a single ensemble from the Coordinated Lattice Simulations (CLS) consortium with $m_\pi=200$ MeV and $N_f=2+1$ dynamical fermions. The finite-volume Luscher a…