Related papers: Resummation of Large Logarithms in the Charm Struc…
We discuss the order alpha_s^2 corrections to the longitudinal spin structure function g_1(x,Q^2,m^2) which are due to heavy flavour contributions. Here Q denotes the virtuality of the photon and m stands for the heavy flavour mass. Since…
The most important part of the order $\alpha_s^2$ corrections to the charm component of the charged-current structure functions $F_2(x,Q^2)$ and $F_3(x,Q^2)$ have been calculated. This calculation is based on the asymptotic form of the…
We examine the charm component F_{2,c}(x,Q^2,m^2) of the proton structure function F_2(x,Q^2) in three different schemes and compare the results with the data in the x and Q^2 region explored by the HERA experiments. Studied are (1) the…
We calculate the massive flavor non-singlet Wilson coefficient for the heavy flavor contributions to the polarized structure function $g_1(x,Q^2)$ in the asymptotic region $Q^2 \gg m^2$ to 3-loop order in Quantum Chromodynamics at general…
I present a calculation of structure functions at leading order which includes an unambiguous inclusion of the leading ln(1/x) terms for each power of alpha_s, and also the correct effects due to the mass of the charm and bottom quarks. I…
The transition from the low $Q^2$ region in deep inelastic scattering where charm production is described by photon-gluon fusion to a region where the charm structure function $F_2^c$ is largely generated by a charm quark density should be…
By combining experimentally measured partial branching fractions for the semileptonic decays D to K l nu and D to pi l nu with lattice calculations of the form factors f_+^{D to K}(q^2) and f_+^{D to pi}(q^2), one can extract the CKM matrix…
Starting from fixed-order perturbation theory (FOPT) we derive expressions for the heavy-flavour components of the deep-inelastic structure functions FL and F2 in the variable-flavour number scheme (VFNS). These expressions are valid in all…
We present the threshold resummation for the cross section for electroproduction of heavy quarks. We work to next-to-leading logarithmic accuracy, and in single-particle inclusive kinematics. We provide next-to-leading and…
We analyze the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ in heavy-quark leptoproduction as a probe of the charm content of the proton. To estimate the charm-initiated contributions, we use the ACOT($\chi$) variable-flavor-number scheme. Our…
We calculate the massive Wilson coefficients for the heavy flavor contributions to the non-singlet charged current deep-inelastic scattering structure functions $F_L^{W^+}(x,Q^2)-F_L^{W^-}(x,Q^2)$ and $F_2^{W^+}(x,Q^2)-F_2^{W^-}(x,Q^2)$ in…
High-energy logarithmic correction are enhanced when the ratio, $x = \frac{Q^2}{s}$ between the typical energy scale of a scattering process $Q$ and the total centre of mass energy available $s$ is small. We discuss recent developments on…
We extend our previous results on small-x resummation in the pure Yang--Mills theory to full QCD with nf quark flavours, with a resummed two-by-two matrix of resummed quark and gluon splitting functions. We also construct the corresponding…
We define a new variable flavour number scheme for use in deep inelastic scattering, motivated by the need to consistently implement high energy resummations alongside a fixed order QCD expansion. We define the DIS(chi) scheme at fixed…
We present an approximate NNLO evaluation of the QCD form factor resumming large logarithmic perturbative contributions in semi-inclusive heavy flavour decays.
We report on progress in the calculation of 3-loop corrections to the deep-inelastic structure functions from massive quarks in the asymptotic region of large momentum transfer $Q^2$. Recently completed results allow us to obtain the…
In the collinear factorization of the form factor for the transition $\gamma^* \pi^0 \to \gamma$ the hard part contains double log terms as $\ln^2 x$ with $x$ as the momentum fraction of partons from 0 to 1. A simple exponentiation for…
We present a determination of the charm quark mass in lattice QCD with three active quark flavours. The calculation is based on PCAC masses extracted from $N_\mathrm{f}=2+1$ flavour gauge field ensembles at five different lattice spacings…
We study soft-gluon radiation for heavy quark production in charged-current Deep Inelastic Scattering processes. We resum large-x contributions to the MSbar coefficient function to next-to-leading logarithmic accuracy and present results…
At low Q^2, charm production in deep-inelastic scattering is adequately described by assuming generation in electroweak boson-light parton scattering (dominantly boson-gluon fusion) which naturally incorporates the correct threshold…