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Ugo Aglietti - One of the best experts on this subject based on the ideXlab platform.

Anton Zettl - One of the best experts on this subject based on the ideXlab platform.

  • Sturm-Liouville Problems Whose Leading Coefficient Function Changes Sign
    Canadian Journal of Mathematics, 2003
    Co-Authors: Xifang Cao, Qingkai Kong, Anton Zettl
    Abstract:

    Fora givenSturm-Liouville equation whoseleading Coefficient Function changessign, we es- tablish inequalities among the eigenvalues for any coupled self-adjoint boundary condition and those for two corresponding separated self-adjoint boundary conditions. By a recent result of Binding and Volkmer, the eigenvalues(unbounded from both below and above) for a separated self-adjoint bound- ary condition can be numbered in terms of the Prangle; and our inequalities can then be used to index the eigenvalues for any coupled self-adjoint boundary condition. Under this indexing scheme, we determine the discontinuities of each eigenvalue as a Function on the space of such Sturm-Liouville problems, and its range as a Function on the space of self-adjoint boundary conditions. We also re- late this indexing scheme to the number of zeros of eigenFunctions. In addition, we characterize the discontinuities of each eigenvalue under a different indexing scheme.

Kainam Thomas Wong - One of the best experts on this subject based on the ideXlab platform.

Israel Gohberg - One of the best experts on this subject based on the ideXlab platform.

J Schoenleber - One of the best experts on this subject based on the ideXlab platform.

  • Two-loop Coefficient Function for DVCS: Vector contributions
    Journal of High Energy Physics, 2020
    Co-Authors: V M Braun, A N Manashov, S Moch, J Schoenleber
    Abstract:

    Using the approach based on conformal symmetry we calculate the two-loop Coefficient Function for the vector flavor-nonsinglet contribution to deeply-virtual Compton scattering (DVCS). The analytic expression for the Coefficient Function in momentum fraction space is presented in the $\overline{\text{MS}}$ scheme. The corresponding next-to-next-to-leading order correction to the Compton form factor $\mathcal{H}$ for a simple model of the generalized parton distribution appears to be rather large: a factor two smaller than the next-to-leading order correction, approximately $\sim 10$\% of the tree level result in the bulk of the kinematic range, for $Q^2=4$~GeV$^2$.

  • two loop Coefficient Function for dvcs vector contributions
    Journal of High Energy Physics, 2020
    Co-Authors: V M Braun, A N Manashov, S Moch, J Schoenleber
    Abstract:

    Using the approach based on conformal symmetry we calculate the two-loop Coefficient Function for the vector flavor-nonsinglet contribution to deeply-virtual Compton scattering (DVCS). The analytic expression for the Coefficient Function in momentum fraction space is presented in the $$ \overline{\mathrm{MS}} $$ scheme. The corresponding next-to-next-to-leading order correction to the Compton form factor ℋ for a simple model of the generalized parton distribution appears to be rather large: a factor two smaller than the next-to-leading order correction, approximately ∼ 10% of the tree level result in the bulk of the kinematic range, for Q2 = 4 GeV2.