Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · hep-ph/0210064

The nucleon's strange electromagnetic and scalar matrix elements

Randy Lewis·W. Wilcox·R. M. Woloshyn
View original source ↗Read source document ↗Export metadata ↓

Abstract

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 discussed in both the lattice and chiral frameworks. The combined results of this study are in good agreement with existing experimental data and predictions are made for upcoming experiments. Possible future refinements of the theoretical method are suggested.

Explore related subjects

hep-phhep-latnucl-th

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Randy Lewis, W. Wilcox, R. M. Woloshyn. 2002-10-03. The nucleon's strange electromagnetic and scalar matrix elements. https://doi.org/10.1103/physrevd.67.013003

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Thermal Leptogenesis in $SO(10)\times U(1)_A$ SUSY GUT

We investigate thermal leptogenesis within a supersymmetric grand unified theory (SUSY GUT) based on the $SO(10) \times U(1)_A$ symmetry, where both the doublet--triplet splitting problem and the unrealistic Yukawa relations are resolved under the natural assumption that all symmetry-allowed interactions appear with $\mathcal{O}(1)$ coefficients. In this framework, the structures of the Dirac neutrino Yukawa couplings and right-handed neutrino masses are determined entirely by the symmetry. The baryon asymmetry of the Universe is computed taking into account the flavor effects, Higgs asymmetry contributions, and the impact of the second-lightest right-handed neutrino. While the predicted asymmetry is too small when all $\mathcal{O}(1)$ coefficients of the Dirac neutrino Yukawa couplings are set to unity, a moderate enhancement factor $r_1 \sim 5.4$ for the lightest right-handed neutrino mass reproduces the observed baryon asymmetry without spoiling low-energy neutrino data. This corresponds to a suppressed lightest neutrino mass, $m_{ν_1} \sim (1/r_1) \times (\text{symmetry-determined value})$, typically $m_{ν_1} \sim 4.5 \times 10^{-4}\,\text{eV}$. We further explore cases where the $\mathcal{O}(1)$ coefficients of the Dirac neutrino Yukawa couplings are $\pm 1$, and find that roughly half of them successfully generate the observed baryon asymmetry for $r_1\leq 11$. Moreover, the others yield results of the correct order of magnitude, although they do not generate the observed Baryon asymmetry. These findings demonstrate that thermal leptogenesis is realized in this $SO(10)\times U(1)_A$ SUSY GUT, establishing a link between the observed baryon asymmetry and predictions for the lightest neutrino mass.

hep-ph↗
arXiv2026

Two-variable longitudinal distribution of the $Λ_b$ in a three-quark light-front model

We determine a normalized two-variable longitudinal distribution of the $Λ_b=(ud)b$ baryon from a covariant three-quark light-front wave function. The scalar $ud$ channel is selected with the good-component structure $Cγ_5γ^+$ and the two independent transverse momenta are integrated without introducing an elementary diquark. The resulting model-scale valence distribution $Ψ_2^{\rm LF}(x_u,x_d)$ retains both the heavy-light and internal-light momentum scales of the parent wave function. It is symmetric under $x_u\leftrightarrow x_d$, is concentrated where both light-quark fractions are small and separates the total light-pair momentum from its internal sharing. For the central parameter set we find $\langle x_u\rangle=\langle x_d\rangle=0.130$, $\langle x_b\rangle=0.739$, $\langleζ^2\rangle=0.153$, and $\langleζ^4\rangle=0.055$, where $ζ=(x_u-x_d)/(x_u+x_d)$. Parameter variations give $\langle x_u\rangle=0.130^{+0.007}_{-0.007}$, $\langle x_b\rangle=0.739^{+0.014}_{-0.014}$, $\langleζ^2\rangle=0.153^{+0.014}_{-0.016}$, and $\langleζ^4\rangle=0.055^{+0.009}_{-0.009}$. The heavy-light momentum partition is controlled mainly by $β_{b,ud}$ and $m_b$, whereas the internal $u$--$d$ sharing is most sensitive to $β_{ud}$. The result provides a compact finite-mass benchmark for three-quark longitudinal structure, with distinct observables for heavy-light momentum sharing and correlations inside the light pair.

hep-ph↗
arXiv2026

Exploring the properties of low-lying excited $Ξ_c$ and $Ξ_c'$ baryons

Motivated by the rapidly accumulating experimental data, we systematically calculate the $Ξ_c$ and $Ξ_c'$ mass spectra for the $1S$-, $1P$-, and $1D$-wave states and investigate the strong decay properties of the $1P$- and $1D$-wave states, thereby interpreting the internal structure of the currently controversial excited states and providing useful guidance for future experimental searches. The main conclusions are summarized as follows. $Ξ_c(2790)$ and $Ξ_c(2815)$ can be well explained as $Ξ_c1P\big|J^P=1/2^-,1\big\rangle_λ$ and $Ξ_c1P\big|J^P=3/2^-,1\big\rangle_λ$, respectively. $Ξ_c(2882)$ may correspond to $Ξ_c1P\big|J^P=1/2^-,0\big\rangle_ρ$ or $Ξ_c1P\big|J^P=1/2^-,1\big\rangle_ρ$; under this interpretation, $Ξ_cπ$ and $Ξ_c'π$ would be promising channels for its detection. $Ξ_c(2923)$ might be assigned to $Ξ_c'1P\big|J^P=3/2^-,1\big\rangle_λ$, but further confirmation is required. $Ξ_c(2939)$ is very likely to be $Ξ_c'1P\big|J^P=3/2^-,2\big\rangle_λ$ and has a good potential to be observed in the final states $Ξ_cπ$ and $Ξ_c'^{*}π$. $Ξ_c(2965)$ can be explained as $Ξ_c'1P\big|J^P=5/2^-,2\big\rangle_λ$ and $Ξ_cπ$ decay channel is a promising additional mode for future experimental searches. $Ξ_c(3055)$ and $Ξ_c(3080)$ can be assigned as the quark configurations $Ξ_c1D\big|J^P=3/2^+,2\big\rangle_{λλ}$ and $Ξ_c1D\big|J^P=5/2^+,2\big\rangle_{λλ}$, respectively. $Ξ_c(3123)$ is possibly state $Ξ_c'1D\big|J^P=1/2^+,1\big\rangle_{λλ}$ or $Ξ_c'1D\big|J^P=5/2^+,3\big\rangle_{λλ}$, with the latter being more favorable. Decay channels $Λ/ΣD$ are very likely to serve as a criterion for distinguishing between these two possible candidates.

hep-ph↗