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The Q^2 dependence of inclusive electron-proton scattering F_2 structure function data in both the nucleon resonance region and the deep inelastic region, at momentum transfers below 5 (GeV/c)^2, is investigated. Moments of F_2 are…

High Energy Physics - Phenomenology · Physics 2014-11-17 C. S. Armstrong , R. Ent , C. E. Keppel , S. Liuti , G. Niculescu , I. Niculescu

We compute the structure function $g_2$ for a gluon target in perturbative QCD at order $\as$. We show that its first moment vanishes, as predicted by the Burkhardt-Cottingham sum rule.

High Energy Physics - Phenomenology · Physics 2009-10-30 A. Gabrieli , G. Ridolfi

In this article, we calculate the scalar form-factors $f_{\pi\pi}(Q^2)$ and $f_{KK}(Q^2)$ in the framework of the light-cone QCD sum rules approach. The numerical value of the $f_{\pi\pi}(Q^2)$ changes quickly with variation of $Q^2$ near…

High Energy Physics - Phenomenology · Physics 2008-11-26 Zhi-Gang Wang

The form factors of the flavor changing vector current between a $\bar q Q$-meson and the lightest $\bar q q$ (pseudoscalar-)meson are computed exactly and explicitly in the 't~Hooft model (planar QCD in $1+1$ dimensions) in the limit that…

High Energy Physics - Theory · Physics 2008-02-03 Benjamin Grinstein

The goal of this thesis is to calculate properties of D-Mesons with QCD-Sum-Rules in order to understand the nature of D-Mesons with positive parity. The result is that such D-Mesons most probably are Mesons with a four quark rather than a…

High Energy Physics - Phenomenology · Physics 2007-05-23 Joerg P. Pfannmoeller

Meson decays are considered within the constituent quark model, making use of the dispersion formulation of the model: Starting with spacelike momentum transfers $q$, meson transition form factors are expressed as relativistic invariant…

High Energy Physics - Phenomenology · Physics 2007-05-23 D. Melikhov

This paper presents a first study of the decay constants of the charged, or flavor-off-diagonal, pseudoscalar mesons to two loops for three flavors of sea quarks, in Partially Quenched Chiral Perturbation Theory (PQ$\chi$PT). Explicit…

High Energy Physics - Lattice · Physics 2009-11-11 Johan Bijnens , Timo A. Lahde

The method of truncated Mellin moments in a solving QCD evolution equations of the nonsinglet structure functions $F_2^{NS}(x,Q^2)$ and $g_1^{NS}(x,Q^2)$ is presented. All calculations are performed within double logarithmic $ln^2x$…

High Energy Physics - Phenomenology · Physics 2007-05-23 D. Kotlorz , A. Kotlorz

We present a Lattice QCD calculation of the second Mellin moments of the nucleon axial, vector and tensor parton distribution functions (PDFs). The calculation is performed at the physical pion mass with two different lattice spacings, and…

Quark mass effects in ${\cal O}(\alpha_s^2)$ QCD corrections to the decay rates of intermediate Higgs bosons are studied. The total hadronic rate and the partial decay rate into bottom quarks are analyzed for the Standard (scalar) Higgs…

High Energy Physics - Phenomenology · Physics 2009-10-28 K. G. Chetyrkin , A. Kwiatkowski

We present the first study of the masses and decay constants of the pseudoscalar $ D $ mesons in two flavors lattice QCD with domain-wall fermion. The gauge ensembles are generated on the $24^3 \times 48 $ lattice with the extent $ N_s = 16…

High Energy Physics - Lattice · Physics 2014-07-31 Wen-Ping Chen , Yu-Chih Chen , Ting-Wai Chiu , Han-Yi Chou , Tian-Shin Guu , Tung-Han Hsieh

We study the higher order corrections of quark masses to the Gell-Mann$-$Oakes$-$Renner (GOR) relation by constructing QCD sum rules exclusively for pseudoscalar mesons from the axial-vector correlation function, $i \int d^4x~ e^{ip\cdot x}…

High Energy Physics - Phenomenology · Physics 2009-11-07 Hungchong Kim

QCD sum rules for the determination of form factors of $\Lambda_b$ and $\Lambda_c$ semileptonic decays are investigated. With a form for the baryonic current appropriate for the limits of the heavy quark symmetries, the different tensor…

High Energy Physics - Phenomenology · Physics 2008-11-26 R. S. Marques de Carvalho , F. S. Navarra , M. Nielsen , E. Ferreira , H. G. Dosch

Our recently completed analysis of the decay constants of both pseudoscalar and vector beauty mesons reveals that in the bottom-quark sector two specific features of the sum-rule predictions show up: (i) For the input value of the…

High Energy Physics - Phenomenology · Physics 2014-11-26 Wolfgang Lucha , Dmitri Melikhov , Silvano Simula

We review recent results for the chiral behavior of meson masses and decay constants and the determination of the light quark masses by the RBC and UKQCD collaborations. We find that one-loop SU(2) chiral perturbation theory represents the…

High Energy Physics - Lattice · Physics 2010-01-21 Enno E. Scholz

We present results for light meson masses and pseudoscalar decay constants from the first of a series of lattice calculations with 2+1 dynamical flavors of domain wall fermions and the Iwasaki gauge action. The work reported here was done…

We calculate mesonic two-point functions in the epsilon-regime of two-flavor QCD on the lattice with exact chiral symmetry. We use gauge configurations of size 16^3 32 at the lattice spacing a \sim 0.11 fm generated with dynamical overlap…

High Energy Physics - Lattice · Physics 2008-11-26 JLQCD Collaboration , H. Fukaya , S. Aoki , S. Hashimoto , T. Kaneko , H. Matsufuru , J. Noaki , K. Ogawa , T. Onogi , N. Yamada

We present the full decomposition of the momentum fraction carried by quarks and gluons in the pion and the kaon. We employ three gauge ensembles generated with $N_f=2+1+1$ Wilson twisted-mass clover-improved fermions at the physical quark…

We compute the second moments of pion and rho parton distribution functions (PDFs) in lattice QCD with $N_f = 2+1$ flavors of improved Wilson fermions. We determine both singlet and non-singlet flavor combinations and, for the first time,…

High Energy Physics - Lattice · Physics 2022-02-02 Marius Löffler , Philipp Wein , Thomas Wurm , Simon Weishäupl , Daniel Jenkins , Rudolf Rödl , Andreas Schäfer , Lisa Walter

We present a calculation of the scalar, vector and tensor pion and kaon form factors using one ensemble of two degenerate light, a strange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with clover improvement. The quark…