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Related papers: $N\pi$-states and the projection method for the nu…

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The nucleon-pion-state contribution in the QCD 3-point function of the pseudoscalar density is calculated to leading order in chiral perturbation theory. It predicts a nucleon-pion-state contamination in lattice estimates for the…

High Energy Physics - Lattice · Physics 2019-09-20 Oliver Bar

The nucleon-pion-state contribution to QCD two-point and three-point functions used in lattice calculations of the nucleon axial form factors are studied in chiral perturbation theory. For small quark masses this contribution is expected to…

High Energy Physics - Lattice · Physics 2019-04-03 Oliver Bar

The nucleon-pion-state contribution to QCD two- and three-point functions used in the calculation of the axial form factors of the nucleon are studied in chiral perturbation theory. For physically small quark masses the nucleon-pion states…

High Energy Physics - Lattice · Physics 2018-08-28 Oliver Bar

It has been observed in multiple lattice determinations of isovector axial and pseudoscalar nucleon form factors, that, despite the fact that the partial conservation of the axialvector current is fulfilled on the level of correlation…

High Energy Physics - Lattice · Physics 2019-02-21 G. S. Bali , S. Collins , M. Gruber , A. Schäfer , P. Wein , T. Wurm

Multi-particle states with additional pions are expected to be a non-negligible source of excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory can be employed to…

High Energy Physics - Lattice · Physics 2017-05-30 Oliver Bar

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…

High Energy Physics - Lattice · Physics 2015-08-04 Brian C. Tiburzi

The nucleon-pion-state contributions to QCD two-point and three-point functions relevant for lattice calculations of the nucleon electromagnetic form factors are studied in chiral perturbation theory. To leading order the results depend on…

High Energy Physics - Lattice · Physics 2021-10-01 Oliver Bar , Haris Colic

The nucleon-pion-state contribution to QCD two-point and three-point functions relevant for lattice calculations of the nucleon electromagnetic form factors are studied in chiral perturbation theory. To leading order the results depend on a…

High Energy Physics - Lattice · Physics 2021-07-07 Oliver Bar , Haris Colic

In the PACS10 project, the PACS collaboration has generated three sets of the PACS10 gauge configurations at the physical point with lattice volume larger than $(10\;{\rm fm})^4$ and three different lattice spacings. The isovector nucleon…

One of the most challenging tasks in lattice calculations of baryon form factors is the analysis and control of excited-state contaminations. Taking the isovector axial form factors of the nucleon as an example, both a dispersive…

High Energy Physics - Lattice · Physics 2021-12-01 Harvey B. Meyer , Konstantin Ottnad , Tobias Schulz

Multi-particle states with additional pions are expected to be a non-negligible source of the excited-state contamination in lattice simulations at the physical point. It is shown that baryon chiral perturbation theory (ChPT) can be…

High Energy Physics - Lattice · Physics 2018-04-18 Oliver Bar

We performed a precise calculation of physical quantities related to the axial structure of the nucleon using 2+1 flavor lattice QCD gauge configuration (PACS10 configuration) generated at the physical point with lattice volume larger than…

We present a lattice calculation of the nucleon iso-vector axial and induced pseudoscalar form factors on the CLS ensembles using $N_{\rm f}=2$ dynamical flavours of non-perturbatively $\mathcal{O}(a)$-improved Wilson fermions and an…

We study the ability of a variety of fitting techniques to extract the ground state matrix elements of the vector current from ratios of nucleon three- and two-point functions that contain contaminations from excited states. Extending our…

High Energy Physics - Lattice · Physics 2014-11-19 G. M. von Hippel , S. Capitani , D. Djukanovic , J. Hua , B. Jäger , P. Junnarkar , H. B. Meyer , T. D. Rae , H. Wittig

We present preliminary results on the axial form factor $G_A(Q^2)$ and the induced pseudoscalar form factor $G_P(Q^2)$ of the nucleon. A systematic analysis of the excited-state contributions to form factors is performed on the CLS ensemble…

High Energy Physics - Lattice · Physics 2014-11-24 P. M. Junnarkar , S. Capitani , D. Djukanovic , G. von Hippel , J. Hua , B. Jäger , H. B. Meyer , T. D. Rae , H. Wittig

We present updated preliminary results for the nucleon electromagnetic form factors for non-perturbatively $\mathcal{O}(a)$ improved Wilson fermions in $N_f=2$ QCD measured on the CLS ensembles. The use of the summed operator insertion…

We employ chiral perturbation theory to calculate the nucleon-pion-state contribution to the 3-point correlation functions measured in lattice QCD to compute various moments of parton distribution functions (quark momentum fraction,…

High Energy Physics - Lattice · Physics 2017-03-08 Oliver Bar

The $N\pi$-state contribution to nucleon 3-pt functions involving the pseudoscalar density $P(x)$ and the time component $A_4(x)$ of the axial vector current are computed to LO in ChPT. In case of the latter the $N\pi$ contribution is…

High Energy Physics - Lattice · Physics 2019-07-09 Oliver Bar

The nucleon axial form factors -- axial $G_A$, induced pseudoscalar $\widetilde{G}_P$ and pseudoscalar $G_P$ -- have displayed large systematics in lattice QCD calculations. The major symptoms were the violation of the partially conserved…

High Energy Physics - Lattice · Physics 2020-02-03 Yong-Chull Jang , Rajan Gupta , Tanmoy Bhattacharya , Sungwoo Park , Boram Yoon , Huey-Wen Lin

We discuss a robust projection method for the extraction of excited-state masses of the nucleon from a matrix of correlation functions. To illustrate the algorithm in practice, we present results for the positive parity excited states of…

High Energy Physics - Lattice · Physics 2010-04-28 M. S. Mahbub , Alan Ò Cais , Waseem Kamleh , B. G. Lasscock , Derek B. Leinweber , Anthony G. Williams
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