F. Olness

Improved parton distributions from global analysis of recent deep inelastic scattering and inclusive jet data

The impact of recent precision measurements of DIS structure functions and inclusive jet production at the Fermilab Tevatron on the global QCD analysis of parton distribution functions is studied in detail. Particular emphasis is placed on exploring the range of variation of the gluon distribution G(x,Q) allowed by these new data. The strong coupling of G(x,Q) with {alpha}{sub s} is fully taken into account. A new generation of CTEQ parton distributions, CTEQ4, is presented. It consists of the three standard sets [modified minimal subtraction ({ovr MS}), deep inelastic scattering (DIS), and leading order (LO)], a series that gives a range of parton distributions with corresponding {alpha}{sub s}`s, and a set with a low starting value of Q. Previously obtained gluon distributions that are consistent with the high E{sub t} jet cross section are also discussed in the context of this new global analysis. {copyright} {ital 1997} {ital The American Physical Society}

nCTEQ15: Global analysis of nuclear parton distributions with uncertainties in the CTEQ framework

We present the new nCTEQ15 set of nuclear parton distribution functions with uncertainties. This fit extends the CTEQ proton PDFs to include the nuclear dependence using data on nuclei all the way up to 208^Pb. The uncertainties are determined using the Hessian method with an optimal rescaling of the eigenvectors to accurately represent the uncertainties for the chosen tolerance criteria. In addition to the Deep Inelastic Scattering (DIS) and Drell-Yan (DY) processes, we also include inclusive pion production data from RHIC to help constrain the nuclear gluon PDF. Furthermore, we investigate the correlation of the data sets with specific nPDF flavor components, and asses the impact of individual experiments. We also provide comparisons of the nCTEQ15 set with recent fits from other groups.

PDF Nuclear Corrections for Charged and Neutral Current Processes

We perform a \chi^2-analysis of Nuclear Parton Distribution Functions (NPDFs) using neutral current charged-lepton Deeply Inelastic Scattering (DIS) and Drell-Yan data for several nuclear targets. The nuclear A dependence of the NPDFs is extracted in a next-to-leading order fit. We compare the nuclear corrections factors F2(Fe)/F2(D) for this charged-lepton data with other results from the literature. In particular, we compare and contrast fits based upon the charged-lepton DIS data with those using neutrino-nucleon DIS data.

Probing gluon and heavy-quark nuclear PDFs with γ + Q production in pA collisions

We present a detailed phenomenological study of direct photon production in association with a heavy-quark jet in pA collisions at the Relativistic Heavy Ion Collider (RHIC) and at the Large Hadron Collider (LHC) at next-to-leading order in QCD. The dominant contribution to the cross-section comes from the gluon-heavy-quark (gQ) initiated subprocess, making γ + Q production a process very sensitive to both the gluon and the heavy-quark parton distribution functions (PDFs). Additionally, the RHIC and LHC experiments are probing complementary kinematic regions in the momentum fraction x carried by the target partons. Thus, the nuclear production ratio

Impact of new neutrino deep inelastic scattering and Drell-Yan data on large-x parton distributions

R_{pA}^{\gamma + Q}

Semi-inclusive deeply inelastic scattering at small {ital q}{sub {ital T}}

can provide strong constraints, over a broad x-range, on the poorly determined nuclear parton distribution functions which are extremely important for the interpretation of results in heavy-ion collisions.

Strange quark parton distribution functions and implications for Drell-Yan boson production at the LHC

New data sets have recently become available for neutrino and antineutrino deep inelastic scattering on nuclear targets and for inclusive dimuon production in pp and pd interactions. These data sets are sensitive to different combinations of parton distribution functions in the large-x region and, therefore, provide different constraints when incorporated into global parton distribution function fits. We compare and contrast the effects of these new data on parton distribution fits, with special emphasis on the effects at large x. The effects of the use of nuclear targets in the neutrino and antineutrino data sets are also investigated.

Resummation of transverse momentum and mass logarithms in DIS heavy quark production.

Measurement of the distribution of hadronic energy in the final state in deeply inelastic electron scattering at DESY HERA can provide a good test of our understanding of perturbative QCD. For this purpose, we consider the energy distribution function, which can be computed without needing final state parton fragmentation functions. We compute this distribution function for finite transverse momentum

Predictions for neutrino structure functions.

{q}_{T}

Differential distributions for next-leading-order analyses of charged current neutrino production of charm quarks

at order