Related papers: Summary of alphas determinations at ZEUS
A simple parametrisation of H1 and ZEUS data at HERA is given for the ranges in x and Q^2 of 10^{-4} - 5.10^{-2} and 5 - 250 GeV^2, respectively. This empirical expression is based on a strikingly similar dependence of the average charged…
A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities $5.5<Q^2<80\,{\rm GeV}^2$ and inelasticities $0.2<y<0.6$ is presented, using data taken with the H1 detector at HERA,…
A combination of the reduced $e^{\pm}p$ cross section, previously measured by H1 and ZEUS, has been performed and leads to well constrained QCD fits of the parton densities in the proton. These results, as well as the high-$Q^2$ neutral…
The ZEUS detector has been upgraded in a number of areas to prepare for the physics opportunities of HERA II. These upgrades, and their physics rationale and promise, are briefly outlined. The measurement of polarisation at HERA II, and its…
The parton momentum densities in the proton are obtained from a NLO QCD analysis of structure functions measured by HERA and fixed target experiments. The uncertainties in these parton densities, the structure functions and related cross…
The upgrade of the HERA accelerator has provided much increased collider luminosity. In turn, the improvements have necessitated a new design for the ZEUS luminosity measurements. The intense synchrotron radiation field, as well as the high…
A novel method to extract the QCD coupling alpha_s from the energy evolution of the moments of the parton-to-hadron fragmentation functions at low fractional hadron momentum z, is presented. The evolution of the moments (multiplicity, peak,…
Jet cross sections in deep-inelastic scattering over a wide region of phase space have been measured at HERA. These cross section measurements provide a thorough test of the implementation of Quantum Chromodynamics in next-to-leading order…
We determine the strong coupling constant alphas and its energy dependence from the pT dependence of the inclusive jet cross section in ppbar collisions at sqrt(s)=1.96 TeV. The strong coupling constant is determined over the transverse…
The production rates and substructure of jets have been studied in charged current deep inelastic e+p scattering for Q**2>200 GeV**2 with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb**-1. Inclusive jet cross sections…
Measurements of jet shapes and subjet multiplicities in photoproduction performed by ZEUS are presented and compared to leading-logarithm parton-shower Monte Carlo models. The predicted differences on the size of gluon- and quark-initiated…
A simultaneous NLO QCD fit of the parton density functions (PDFs) of the proton and of the strong coupling $\alpha_{S}(M_{Z})$ is presented. The analysis is based on combined H1 and ZEUS inclusive DIS cross section measurements together…
The cross section and the proton structure function F2 for neutral current deep inelastic e+p scattering have been measured with the ZEUS detector at HERA using an integrated luminosity of 30 pb-1. The data were collected in 1996 and 1997…
The ZEUS inclusive cross-section data from HERA-I, for charged and neutral current processes, taken with $e^+$ and $e^-$ beams, have been used in a new NLO QCD analysis to extract the parton distribution functions (PDFs) of the proton…
I present a small selection of the many QCD studies that have been performed at HERA. I concentrate on results that have been made available in the past year. Results are presented on the QCD description of the parton density functions,…
After fifteen years of running and a further five years of analysis, the final inclusive deep inelastic scattering cross sections from H1 and ZEUS have been published. Measurements of neutral current and charged current processes in ep…
Recent results on jets and the hadronic final state from the HERA collaborations H1 and ZEUS are reviewed.
The strong coupling constant $\alpha_s(M_Z)$ is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic $ep$ scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order…
Next-to-leading order QCD analyses of the ZEUS data on deep inelastic scattering together with fixed-target data have been perfomed, from which the gluon and the quark densities of the proton and the value of the strong coupling constant,…
The azimuthal correlation angle, $\Delta\phi$, between the scattered lepton and the leading jet in deep inelastic $e^{\pm}p$ scattering at HERA has been studied using data collected with the ZEUS detector at a centre-of-mass energy of…