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相关论文: Three-particle $N\pi\pi$ state contribution to the…

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We present the first direct $N_f=2$ lattice QCD computation of two- and three-$\pi^+$ scattering quantities that includes an ensemble at the physical point. We study the quark mass dependence of the two-pion phase shift, and the…

高能物理 - 格点 · 物理学 2021-05-26 Matthias Fischer , Bartosz Kostrzewa , Liuming Liu , Fernando Romero-López , Martin Ueding , Carsten Urbach

We explore the chiral aspects of extrapolation of observables calculated within lattice QCD, using the nucleon magnetic moments as an example. Our analysis shows that the biggest effects of chiral dynamics occur for quark masses…

高能物理 - 唯象学 · 物理学 2007-05-23 A. W. Thomas , D. B. Leinweber , D. H. Lu

By calculating the contribution of the $\pi-\pi$ three-body force to the three-nucleon binding energy in terms of the $\pi N$ amplitude using perturbation theory, we are able to determine the importance of the energy dependence and the…

核理论 · 物理学 2009-10-28 T-Y Saito , I. R. Afnan

By calculating the contribution of the $\pi-\pi$ three-body force to the three-nucleon binding energy in terms of the $\pi N$ amplitude using perturbation theory, we are able to determine the contribution of the different $\pi N$ partial…

核理论 · 物理学 2008-11-26 T-Y. Saito , I. R. Afnan

We investigate contributions of excited states to nucleon matrix elements by studying the two- and three-point functions using nucleon and pion-nucleon interpolating fields. This study is carried out using twisted mass fermion ensembles…

高能物理 - 格点 · 物理学 2024-01-02 Constantia Alexandrou , Giannis Koutsou , Yan Li , Marcus Petschlies , Ferenc Pittler

Techniques to compute hadron properties from lattice QCD rely upon the limit of long time separation. For baryons, the signal-to-noise problem often restricts one to time separations that are not ideally long, and for which couplings to…

高能物理 - 格点 · 物理学 2015-08-04 Brian C. Tiburzi

We calculate in (two-loop) chiral perturbation theory the local NN-potentials generated by the three-pion exchange diagrams with one insertion from the second order chiral effective pion-nucleon Lagrangian proportional to the low-energy…

核理论 · 物理学 2009-11-07 Norbert Kaiser

The I=2 pipi scattering length is calculated in fully-dynamical lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations (with fourth-rooted staggered sea quarks) at four light-quark masses. Two- and…

It would be very useful to find a way of reducing excited-state effects in lattice QCD calculations of nucleon structure that has a low computational cost. We explore the use of hybrid interpolators, which contain a nontrivial gluonic…

We investigate an improved method to extract nucleon matrix elements from lattice 3-point functions using a generalized eigenvalue problem (GEVP) with nucleon and pion-nucleon interpolating fields. Our method avoids the computation of the…

高能物理 - 格点 · 物理学 2024-12-11 Constantia Alexandrou , Giannis Koutsou , Yan Li , Marcus Petschlies , Ferenc Pittler

This work discusses reliability, possible obstacles and the future perspective of chiral extrapolation of lattice results. In the first part, chiral perturbation theory fits to lattice calculations of the nucleon mass are thoroughly…

高能物理 - 格点 · 物理学 2007-05-23 Bernhard U. Musch

Nucleon weak matrix elements can be extracted from nucleon correlation functions with lattice QCD simulations. The signal-to-noise ratio prohibits the analysis at large source-sink separations and as a consequence, excited state…

高能物理 - 格点 · 物理学 2024-06-03 Lorenzo Barca , Gunnar Bali , Sara Collins

Third order chiral perturbation theory accounts for the $\pi-N$ scattering phase shift data out to energies slightly below the position of the $\Delta$ resonance. The low energy constants are not accurately determined. Explicit inclusion of…

核理论 · 物理学 2017-08-23 P. J. Ellis

The axial charge of the nucleon $g_A$ and the pion decay constant $f_\pi$ are computed in two-flavor lattice QCD. The simulations are carried out on lattices of various volumes and lattice spacings. Results are reported for pion masses as…

高能物理 - 格点 · 物理学 2015-06-15 R. Horsley , Y. Nakamura , A. Nobile , P. E. L. Rakow , G. Schierholz , J. M. Zanotti

This work presents a determination of potential short-distance contributions to the unphysical $\pi^-\rightarrow\pi^+ e^- e^-$ decay through lattice QCD calculations. The hadronic contributions to the transition amplitude are described by…

高能物理 - 格点 · 物理学 2023-05-17 William Detmold , William I. Jay , David J. Murphy , Patrick R. Oare , Phiala E. Shanahan

In this talk, I present my personal view on the status of lattice QCD calculations. I emphasize the role played by the chiral perturbation theory (ChPT) in analyzing the lattice data of various physical quantities, including chiral…

高能物理 - 唯象学 · 物理学 2009-12-31 Shoji Hashimoto

Quantum fluctuations in QCD influence nucleon structure and interactions, with pion production serving as a key probe of chiral dynamics. In this study, we present a lattice QCD calculation of multipole amplitudes at threshold, related to…

高能物理 - 格点 · 物理学 2025-04-23 Yu-Sheng Gao , Zhao-Long Zhang , Xu Feng , Lu-Chang Jin , Chuan Liu , Ulf-G. Meißner

Previous extrapolations of lattice QCD results for the nucleon mass to the physically relevant region of small quark masses, using chiral effective field theory, are extended and expanded in several directions. A detailed error analysis is…

高能物理 - 格点 · 物理学 2007-05-23 M. Procura , B. U. Musch , T. Wollenweber , T. R. Hemmert , W. Weise

Chiral symmerty is presumed to be a crucial component in the strong interaction and QCD, but its role in spectroscopy, especially for baryons, has not been fully explored. Compounding this, chiral fermions are uncommon in lattice…

高能物理 - 格点 · 物理学 2018-12-07 Jacob Fallica , Keh-Fei Liu , Jian Liang , Gen Wang , Yi-Bo Yang

We investigate contributions of excited states to nucleon matrix elements computed in lattice QCD by employing, in addition to the standard nucleon interpolating operator, pion-nucleon ($\pi$-$N$) operators. We solve a generalized…

高能物理 - 格点 · 物理学 2024-11-25 Constantia Alexandrou , Giannis Koutsou , Yan Li , Marcus Petschlies , Ferenc Pittler