Related papers: Towards parton distributions with fitted charm
The charm quark structure function $F^c_2$ and the longitudinal structure function $F_l^p$ are directly sensitive to the gluon content of proton and therefore are crucial in understanding of proton structure function, in particular at low…
In a consistently formulated pQCD framework incorporating non-zero mass heavy quark partons, there is still the freedom to define parton distributions obeying either mass-independent or mass-dependent evolution equations, contrary to…
At NNLO it is particularly important to have a Variable-Flavour Number Scheme (VFNS) to deal with heavy quarks because there are major problems with both the zero mass variable-flavour number scheme and the fixed-flavour number scheme. I…
We present a new set of parton distributions, NNPDF3.1, which updates NNPDF3.0, the first global set of PDFs determined using a methodology validated by a closure test. The update is motivated by recent progress in methodology and available…
Heavy quark parton distribution functions (PDFs) play an important role in several Standard Model and New Physics processes. Most PDF analyses rely on the assumption that the charm and bottom PDFs are generated perturbatively by gluon…
We consider some trends, achievements and a series of remaining problems in the precision determination of parton distribution functions. For the description of the scaling violations of the deep-inelastic scattering data, forming the key…
We describe the impact on PDF extractions of the 'Physical Scheme', a heavy-quark mass scheme that accounts for the effects of intrinsic heavy-quarks and provides a way to smoothly transition over the heavy-quark thresholds. The…
In this contribution I discuss recent and ongoing progress on the inclusion of resummation effects in the fit of parton distributions.
We propose a new method to calculate parton distribution functions (PDFs) from lattice correlations of boosted quarks and gluons in the Coulomb gauge. Compared to the widely used gauge-invariant Wilson-line operators, these correlations…
We investigate the uncertainties of the heavy-quark parton distribution functions in the variable flavor number scheme. Because the charm- and bottom-quark parton distribution functions (PDFs) are constructed predominantly from the gluon…
Parton distribution functions (PDFs) are nonperturbative quantities describing the relation between a hadron and quarks and gluons within it. We propose to extract PDFs from QCD global analysis of "data" generated by lattice QCD…
We extend the FONLL general-mass variable-flavour-number scheme to the case of longitudinally polarised DIS structure functions, accounting for perturbative corrections up to $\mathcal{O}(\alpha_s^2)$. We quantify the impact of charm quark…
We present a review of the current understanding of the heavy quark distributions in the nucleon and their impact on collider physics. The origin of strange, charm and bottom quark pairs at high light-front (LF) momentum fractions in hadron…
We survey some of the recent developments in the extraction and application of heavy quark Parton Distribution Functions (PDFs). We also highlight some of the key HERA measurements which have contributed to these advances.
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…
We discuss a general framework for the inclusion of heavy quark mass contributions to deep-inelastic structure functions and their perturbative matching to structure functions computed in variable-mass schemes. Our approach is based on the…
Within the framework of heavy quark effective theory and chiral perturbation theory, masses and splittings of heavy charm mesons are studied. A mass formula is used for comprehensive analysis of low lying charm meson states.The variation of…
We present the first lattice-QCD calculation of the unpolarized strange and charm parton distribution functions using large-momentum effective theory (LaMET). We use a lattice ensemble with 2+1+1 flavors of highly improved staggered quarks…
We introduce a Hybrid Variable Flavor Number Scheme for heavy flavors, denoted H-VFNS, which incorporates the advantages of both the traditional Variable Flavor Number Scheme (VFNS) as well as the Fixed Flavor Number Scheme (FFNS). By…
Focusing on hadron scattering at large partonic momentum fractions $x$, we compare nonperturbative QCD predictions for the asymptotic behavior of DIS structure functions and parton distribution functions (PDFs) to the $x$ and $Q$ dependence…