Related papers: Charm in Deep-Inelastic Scattering
Multiple parton scattering and induced parton energy loss is studied in deeply inelastic scattering (DIS) off nuclei. The effect of multiple scattering of a highly off-shell quark and the induced parton energy loss is expressed in terms of…
Up to now, the existence of intrinsic (or valence-like) heavy quark component of the proton distribution functions has not yet been confirmed or rejected. The LHC with pp-collisions at $\sqrt{s}$ = 7-13 TeV can supply us with extra unique…
We study the expansion method for the gluon distribution function at low x values and calculate the charm structure functions in the LO and NLO analysis. Our results provide a compact formula for the ratio $R^{c} =F^{c}_{L}/F^{c}_{2}$,…
Starting at 3-loop order, the massive Wilson coefficients for deep-inelastic scattering and the massive operator matrix elements describing the variable flavor number scheme receive contributions of Feynman diagrams carrying quark lines…
Background: Intrinsic charm, nonperturbative charm in the hadron wavefunction, has long been speculated but has never been satisfactorily proven. Open charm and $J/\psi$ measurements in a fixed-taget configuration at the LHCb searched for…
We study the threshold corrections to the structure functions in deep-inelastic scattering (DIS) at the fifth logarithmic (N$^4$LL) order of the soft-gluon exponentiation in massless perturbative QCD. Using recent results for the splitting…
Precise measurements of charm production in deep inelastic scattering are presented and compared with next-to-leading-order QCD. The data show sensitivity to the choice of parametrisation of the gluon density in the proton and could be used…
The scaling properties at low $x$ of the proton DIS cross section and its charm component are analyzed with the help of the quality factor method. Scaling properties are tested both in the deep inelastic scattering data and in the structure…
We present a first calculation of the heavy flavor contribution to the longitudinally polarized DIS structure function $g_1$, differential in the transverse momentum or the rapidity of the observed heavy antiquark $\overline{Q}$. All…
The Thorne-Roberts variable flavour number scheme (VFNS) for heavy quarks is presented in detail for the specific case of charged current DIS. As in neutral current DIS this provides a smooth extrapolation from the fixed flavour number…
We report on our first set of results for charm physics, using a mixed-action setup with maximally twisted valence fermions on CLS $N_f=2+1$ ensembles. This setup avoids the need of improvement coefficients to subtract $O(am_c)$ effects.…
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…
The running charm-quark mass in the $\bar{MS}$ scheme is determined from weighted finite energy QCD sum rules (FESR) involving the vector current correlator. Only the short distance expansion of this correlator is used, together with…
We argue that the difference between the structure functions corresponding to deep inelastic scattering with and without heavy quarks in the current fragmentation region scales at high Q^2 and fixed (low) x.
We have generalized the approach of Brodsky {\it et al.} for the intrinsic charm quark distribution in the nucleons to the light-quark sector involving intrinsic $\bar u, \bar d, s$ and $\bar s$ sea quarks. We compare the calculations with…
Expectations for the momentum distribution of nonperturbative charm and bottom quarks in the proton are derived from a variety of models for the Fock space wave function on the light cone.
In the Bjorken limit of the present theory of deep inelastic scattering (DIS) the structure functions (up to anomalous dimensions and perturbative QCD corrections) are described by the parton model. However the current operator in the…
A new interpretation of intrinsic charm phenomenon based on the assumption of pentaquark $\left| u u d c\bar{c} \right>$ mixing with a proton is offered. The structure function of the $c$-quark in the pentaquark is constructed. Mixing…
We compute the coefficient functions for heavy-quark initiated charged-current deep-inelastic scattering through $\mathcal{O}(\alpha_s^2)$, retaining full mass dependence for a single heavy-quark flavor. The calculation employs a cut-based…
We discuss an NNLO realization of the general mass scheme S-ACOT-$\chi$ for treatment of heavy-flavour production in neutral current deep-inelastic scattering. Practical implementation of the NNLO calculation is illustrated on the example…