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Related papers: Strange quark content of the nucleon and dark matt…

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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 evaluate the matrix element of $\bar{q} q$ in hadron states on a lattice. We find substantial mixing of the connected and disconnected contributions so that the lattice result that the disconnected contribution to the nucleon is large…

High Energy Physics - Lattice · Physics 2008-11-26 C. Michael , C. McNeile , D. Hepburn , UKQCD Collaboration

We report a lattice QCD calculation of the strange quark contribution to the nucleon's magnetic moment and charge radius. This analysis presents the first direct determination of strange electromagnetic form factors including at the…

High Energy Physics - Phenomenology · Physics 2017-01-30 Raza Sabbir Sufian , Yi-Bo Yang , Andrei Alexandru , Terrence Draper , Keh-Fei Liu , Jian Liang

The chiral constituent quark model ($\chi$CQM) has been extended to calculate the flavor structure of the nucleon through the meson-nucleon sigma terms which have large contributions from the quark sea and are greatly affected by chiral…

High Energy Physics - Phenomenology · Physics 2015-05-28 Harleen Dahiya , Neetika Sharma

We demonstrate that a nonzero strangeness contribution to the spacelike electromagnetic form factor of the nucleon is evidence for a strange-antistrange asymmetry in the nucleon's light-front wave function, thus implying different…

There are several different experimental indications, such as the strangeness contribution to the magnetic moment of the proton, sigma_{\pi N} term, strange spin polarization, ratio of strange and non strange quark flavor distributions…

High Energy Physics - Phenomenology · Physics 2008-11-26 Harleen Dahiya , Manmohan Gupta

The low-energy neutron-Sigma^- interactions determine, in part, the role of the strange quark in dense matter, such as that found in astrophysical environments. The scattering phase shifts for this system are obtained from a numerical…

High Energy Physics - Lattice · Physics 2013-05-30 S. R. Beane , E. Chang , S. D. Cohen , W. Detmold , H. -W. Lin , T. C. Luu , K. Orginos , A. Parreno , M. J. Savage , A. Walker-Loud

The last few years have seen a dramatic improvement in our knowledge of the strange form factors of the nucleon. With regard to the vector from factors the level of agreement between theory and experiment gives us considerable confidence in…

Nuclear Theory · Physics 2015-06-03 A. W. Thomas , P. E. Shanahan , R. D. Young

We study the nucleon matrix elements of the quark scalar-density operator using maximally twisted mass fermions with dynamical light ($u$,$d$), strange and charm degrees of freedom. We demonstrate that in this setup the nucleon matrix…

High Energy Physics - Lattice · Physics 2015-06-04 Simon Dinter , Vincent Drach , Roberto Frezzotti , Gregorio Herdoiza , Karl Jansen , Giancarlo Rossi

We present a non-perturbative calculation of the strangeness of the nucleon $y_N$ within the framework of lattice QCD. This observable is known to be an important cornerstone to interpret results from direct dark matter detection…

Quenched lattice QCD simulations and quenched chiral perturbation theory are used together for this study of strangeness in the nucleon. Dependences of the matrix elements on strange quark mass, valence quark mass and momentum transfer are…

High Energy Physics - Phenomenology · Physics 2009-11-07 Randy Lewis , W. Wilcox , R. M. Woloshyn

The contribution of strange sea quarks to the proton mass and spin, as well as the related pion-nucleon sigma term, are briefly revisited, in the light of new experimental and lattice results. Also the predictions of chiral perturbation…

High Energy Physics - Phenomenology · Physics 2007-05-23 Michael D. Scadron , Frieder Kleefeld , George Rupp

Strange matrix elements of the nucleon are calculated within the light-cone formulation of the meson cloud model. The $Q^2$ dependence of the strange vector and axial vector form factors is computed, and the strangeness radius and magnetic…

High Energy Physics - Phenomenology · Physics 2008-11-26 W. Melnitchouk , M. Malheiro

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

Effective quark magnetic moments are extracted from experimental measurements as a function of the strangeness magnetic moment of the nucleon. Assumptions made in even the most general quark model analyses are ruled out by this…

Nuclear Theory · Physics 2009-10-28 Derek B. Leinweber

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

Precise knowledge of the strange and antistrange quark distributions of the nucleon is a major step toward better understanding of the strong interaction and the nucleon structure. Moreover, the $ s-\bar s $ asymmetry in the nucleon plays…

High Energy Physics - Phenomenology · Physics 2016-02-02 Maral Salajegheh

The status of lattice calculations in the light hadron sector is reviewed. Special emphasis is given to recent lattice determinations of the mass of the strange quark. The impact of non-perturbative renormalization and control over lattice…

High Energy Physics - Phenomenology · Physics 2008-11-26 Hartmut Wittig

A formalism based on a relativistic plane wave impulse approximation is developed to investigate the strange-quark content ($g_{A}^{s}$) of the axial-vector form factor of the nucleon via neutrino-nucleus scattering. Nuclear structure…

Nuclear Theory · Physics 2008-11-26 B. I. S. van der Ventel , J. Piekarewicz

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