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We investigate the strange electric and magnetic form factors of the nucleon in the framework of heavy baryon chiral perturbation theory to third order in the chiral expansion. All counterterms can be fixed from data. In particular, the two…

Nuclear Theory · Physics 2009-10-31 Thomas R. Hemmert , Bastian Kubis , Ulf-G. Meißner

We present the strange electromagnetic form factors of the nucleon using lattice QCD with $N_f=2+1+1$ twisted mass clover-improved fermions and quark masses tuned to their physical values. Using four ensembles with lattice spacings of…

Several parameters characterizing the strangeness content of the nucleon have been calculated in the chiral constituent quark model with configuration mixing (\chiCQM_{config}) which is known to provide a satisfactory explanation of the…

High Energy Physics - Phenomenology · Physics 2007-10-19 Harleen Dahiya , Manmohan Gupta

Magnetic form factors corresponding to elastic electron scattering from odd-A nuclei are presented. The calculations are carried out in plane-wave Born approximation. The one-body properties are obtained in a deformed self-consistent…

We calculate the total and differential quasielastic cross sections for neutrino and antineutrino scattering on nucleons using up to date fits to the nucleon elastic electromagnetic form factors $G_E^p$, $G_E^n$, $G_M^p$, $G_M^n$, and weak…

High Energy Physics - Experiment · Physics 2007-05-23 H. Budd , A. Bodek , J. Arrington

We investigate the effect of different relativistic spin couplings of constituent quarks on nucleon electroweak properties. Within each quark spin coupling scheme the correlations between static electroweak observables are found to be…

Nuclear Theory · Physics 2011-07-19 E. F. Suisso , W. R. B. de Araujo , T. Frederico , M. Beyer , H. J. Weber

Several spin and flavor dependent parameters characterizing the strangeness content of the nucleon have been calculated in the chiral constituent quark model with configuration mixing (\chiCQM_{config}) which is known to provide a…

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

The parity-violating cross-section asymmetry in the elastic scattering of polarized electrons from unpolarized protons has been measured at a four-momentum transfer squared Q2 = 0.624 GeV and beam energy E =3.48 GeV to be A_PV = -23.80 +/-…

We study the sensitivity of neutral-current neutrino-nucleus scattering to the strange-quark content of the axial-vector form factor of the nucleon. A model-independent formalism for this reaction is developed in terms of eight nuclear…

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

The complete world set of parity violating electron scattering data up to Q^2~0.3 GeV^2 is analysed. We extract the current experimental determination of the strange electric and magnetic form factors of the proton, as well as the weak…

Nuclear Experiment · Physics 2010-02-17 R. D. Young , J. Roche , R. D. Carlini , A. W. Thomas

A key question in understanding the structure of nucleons involves the role of sea quarks in their ground state electromagnetic properties such as charge and magnetism. Parity-violating electron scattering, when combined with determination…

Nuclear Experiment · Physics 2015-06-26 E. J. Beise

The charge and magnetic form factors of light nuclei, mainly for mass numbers A<=4, provide a sensitive test of our understanding of nuclei. A number of "exact" calculations of the wave functions starting from the nucleon-nucleon…

Nuclear Experiment · Physics 2009-11-07 Ingo Sick

The contributions of strange quarks to the nucleon mass and the nucleon spin are investigated in a mixed action scheme employing domain wall valence quarks and quark loops on MILC asqtad dynamical fermion ensembles. Results are presented…

High Energy Physics - Lattice · Physics 2011-08-19 Michael Engelhardt

The nucleon strange vector and isoscalar electromagnetic form factors are studied using a spectral decomposition. The K\bar{K} contribution to the electric and magnetic radii as well as the magnetic moment is evaluated to all orders in the…

High Energy Physics - Phenomenology · Physics 2014-11-17 H. -W. Hammer , M. J. Ramsey-Musolf

Quark line disconnected matrix elements of an operator, such as the axial current, are difficult to compute on the lattice. The standard method uses a stochastic estimator of the operator, which is generally very noisy. We discuss and…

High Energy Physics - Lattice · Physics 2019-01-16 R. Horsley , Y. Nakamura , H. Perlt , D. Pleiter , P. E. L. Rakow , G. Schierholz , A. Schiller , H. Stüben , R. D. Young , J. M. Zanotti

Observables from parity violation in elastic electron-nucleon scattering and neutral current quasi-elastic neutrino-nucleus scattering are employed as tools to improve the current knowledge on the strangeness content in the nucleon.

Nuclear Theory · Physics 2014-01-29 R. González-Jiménez , J. A. Caballero

We report new measurements of the parity-violating asymmetry A_PV in elastic scattering of 3 GeV electrons off hydrogen and 4He targets with <theta_lab>~6.0 degrees. The 4He result is A_PV = (+6.40 +/- 0.23 (stat) +/- 0.12 (syst)) x10^-6.…

Nuclear Experiment · Physics 2012-08-27 The HAPPEX Collaboration

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…

A new measurement of the parity violating asymmetry in elastic electron scattering on hydrogen at backward angles and at a four momentum transfer of Q^2=0.22 (GeV/c)^2 is reported here. The measured asymmetry is A_LR=(-17.23 +- 0.82_stat…

We propose new method which allows determination of the strange-sea quark spin distribution in the nucleon through measurement of various inclusive and semi-inclusive polarized deep inelastic electron- or muon-proton reactions. It is shown,…

High Energy Physics - Phenomenology · Physics 2008-11-26 L. Grigoryan