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Related papers: The Scalar Strange Content of the Nucleon from Lat…

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The scalar strangeness content of the nucleon, characterized by the so-called strangeness-nucleon sigma term, is of fundamental importance in understanding its sea-quark flavor structure. We report a determination of the octet baryon sigma…

High Energy Physics - Phenomenology · Physics 2015-06-19 Xiu-Lei Ren , Li-Sheng Geng , Jie Meng

We calculate the nucleon sigma term in two-flavor lattice QCD utilizing the Feynman-Hellman theorem. Both sea and valence quarks are described by the overlap fermion formulation, which preserves exact chiral and flavor symmetries on the…

High Energy Physics - Lattice · Physics 2009-01-09 H. Ohki , H. Fukaya , S. Hashimoto , T. Kaneko , H. Matsufuru , J. Noaki , T. Onogi , E. Shintani , N. Yamada , for JLQCD Collaboration

We discuss the calculation of disconnected diagrams needed for determining the strange quark content of the nucleon on the lattice. We present results for the strange scalar form factor and the related parameter f_Ts, which enters into the…

High Energy Physics - Lattice · Physics 2009-01-30 Ronald Babich , Richard Brower , Michael Clark , George Fleming , James Osborn , Claudio Rebbi

The strangeness of the nucleon, <N|ss|N> - <0|ss|0>, is a quantity of interest for interpreting the results of dark matter detection experiments as well as for exploring the structure of the nucleon itself. We present a calculation of this…

High Energy Physics - Lattice · Physics 2010-11-05 Walter Freeman , Doug Toussaint

Strange quark content of the nucleon is calculated in dynamical lattice QCD employing the overlap fermion formulation. For this quantity, exact chiral symmetry guaranteed by the Ginsparg-Wilson relation is crucial to avoid large…

High Energy Physics - Lattice · Physics 2011-06-21 JLQCD collaboration , K. Takeda , S. Aoki , S. Hashimoto , T. Kaneko , J. Noaki , T. Onogi

We calculate the strange quark content of the nucleon in 2+1-flavor lattice QCD. Chirally symmetric overlap fermion formulation is used to avoid the contamination from up and down quark contents due to an operator mixing between strange and…

High Energy Physics - Lattice · Physics 2015-03-20 JLQCD Collaboration , H. Ohki , K. Takeda , S. Aoki , S. Hashimoto , T. Kaneko , H. Matsufuru , J. Noaki , T. Onogi

We calculate the "strange quark content of the nucleon", <N| s s_bar |N>, which is important for interpreting the results of some dark matter detection experiments. The method is to evaluate quark-line disconnected correlations on the MILC…

High Energy Physics - Lattice · Physics 2011-03-18 D. Toussaint , W. Freeman

The strange quark scalar content plays an important role in both the description of nucleon structure and in the determination of dark matter direct detection cross sections. As a measure of the strange-quark contribution to the nucleon…

High Energy Physics - Lattice · Physics 2013-01-10 R. D. Young

We determine the strangeness and light quark fractions of the nucleon mass by computing the quark line connected and disconnected contributions to the matrix elements m_q <N|qbar q|N> in lattice QCD, using the non-perturbatively improved…

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…

High Energy Physics - Phenomenology · Physics 2017-08-23 R. Lewis , W. Wilcox , R. M. Woloshyn

Contributions of strange quarks to the mass and spin of the nucleon, characterized by the observables f_Ts and Delta s, respectively, are investigated within lattice QCD. The calculation employs a 2+1-flavor mixed-action lattice scheme,…

High Energy Physics - Lattice · Physics 2013-05-30 M. Engelhardt

The strangeness contribution to the electric and magnetic properties of the nucleon has been under investigation experimentally for many years. Lattice Quantum Chromodynamics (LQCD) gives theoretical predictions of these measurements by…

High Energy Physics - Lattice · Physics 2008-01-24 Dean Darnell

We present a QCD calculation of the $u$, $d$ and $s$ scalar quark contents of nucleons based on $47$ lattice ensembles with $N_f = 2+1$ dynamical sea quarks, $5$ lattice spacings down to $0.054\,\text{fm}$, lattice sizes up to…

High Energy Physics - Lattice · Physics 2016-05-12 S. Durr , Z. Fodor , C. Hoelbling , S. D. Katz , S. Krieg , L. Lellouch , T. Lippert , T. Metivet , A. Portelli , K. K. Szabo , C. Torrero , B. C. Toth , L. Varnhorst

We discuss the general method of the calculation of the nucleon matrix elements of an operator associated with nonvalence quarks. The method is based on the QCD sum rules and low energy theorems. As an application of these considerations,…

High Energy Physics - Phenomenology · Physics 2011-04-15 Ariel R. Zhitnitsky

By using lattice QCD computations we determine the sigma terms and strangeness content of all octet baryons by means of an application of the Hellmann-Feynman theorem. In addition to polynomial and rational expressions for the quark mass…

High Energy Physics - Lattice · Physics 2016-03-01 S. Durr , Z. Fodor , T. Hemmert , C. Hoelbling , J. Frison , S. D. Katz , S. Krieg , T. Kurth , L. Lellouch , T. Lippert , A. Portelli , A. Ramos , A. Schafer , K. K. Szabo

Lattice QCD calculations with chiral fermions of the $\pi$N sigma term $\sigma_{\pi N}$ and strangeness sigma term $\sigma_{sN}$ including chiral interpolation with continuum and volume corrections are provided in this work, with the…

High Energy Physics - Lattice · Physics 2016-09-14 Yi-Bo Yang , Andrei Alexandru , Terrence Draper , Jian Liang , Keh-Fei Liu

We present a calculation of the strangeness and charmness contents <N|\bar{s}s|N> and <N|\bar{c}c|N> of the nucleon from dynamical lattice QCD with 2+1 flavors. The calculation is performed with overlap valence quarks on 2+1-flavor…

High Energy Physics - Phenomenology · Physics 2013-08-20 M. Gong , A. Alexandru , Y. Chen , T. Doi , S. J. Dong , T. Draper , W. Freeman , M. Glatzmaier , A. Li , K. F. Liu , Z. Liu

We determine the quark contributions to the nucleon spin Delta s, Delta u and Delta d as well as their contributions to the nucleon mass, the sigma-terms. This is done by computing both, the quark line connected and disconnected…

The outcome of the SAMPLE Experiment suggests that the strange-quark contribution to the nucleon magnetic moment, G_M^s(0), may be greater than zero. This result is very difficult to reconcile with expectations based on the successful…

High Energy Physics - Lattice · Physics 2010-02-17 Derek B. Leinweber , Anthony W. Thomas

We evaluate the light, strange and charm scalar content of the nucleon using one lattice QCD ensemble generated with two degenerate light quarks with mass fixed to their physical value. We use improved techniques to evaluate the…

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