Related papers: Event shape studies at HERA
We reexamine the contact interaction hypothesis for excess high-$Q^2$ events seen at HERA in $e^+ p \to e^+ X$ scattering. We consider the most general structure of contact interactions insisting on $SU(3)_C\times SU(2)_L \times U(1)_Y$…
We study the event shape variables, transverse energy energy correlation TEEC $(\cos \phi)$ and its asymmetry ATEEC $(\cos \phi)$ in deep inelastic scattering (DIS) at the electron-proton collider HERA, where $\phi$ is the angle between two…
A brief review is given of the status of nucleon spin structure functions as determined from polarized deep inelastic lepton-nucleon scatttering, including current outstanding problems. The characteristics of a polarized HERA collider, some…
For high energy processes ($M\gg \Lambda_{QCD}$) there are infrared safe hadronic shape variables that have a calculable perturbative expansion in $\alpha_s(M^2)$. However, nonperturbative power suppressed corrections to these variables are…
The inclusive neutral and charged current deep inelastic scattering processes at high Q2 provide the main basis for electroweak studies at HERA. These studies include the determination of the W boson propagator mass and weak neutral current…
Highlights are presented mainly from two recent measurements of the diffractive Deep Inelastic Scattering cross section at HERA. In the first, the process $ep\to eXp$ is studied by tagging the leading final state proton. In the second,…
A measurement of the inclusive ep scattering cross section is presented in the region of low momentum transfers, 0.2 GeV^2 < Q^2 < 12 GeV^2, and low Bjorken x, 5x10^-6 < x < 0.02. The result is based on two data sets collected in dedicated…
Di-jet event rates have been measured for deep-inelastic scattering in the kinematic domain ~5 < Q^2 < ~100 GeV^2 and ~10^(-4) < x_Bj < ~10^(-2), and for jet transverse momenta squared p_t^2 > ~Q^2. The analysis is based on data collected…
The first measurements of the cross sections for neutral and charged current deep inelastic scattering in e+p collisions with longitudinally polarised positron beams are presented. The total cross section for e+p charged current deep…
The production of jets is studied in deep-inelastic ep scattering at large negative four momentum transfer squared 150<Q^2<15000 GeV^2 using HERA data taken in 1999-2007, corresponding to an integrated luminosity of 395 pb^-1. Inclusive…
Two-jet cross sections in deep inelastic scattering at HERA are calculated in next-to-leading order. The QCD corrections are implemented in a new $ep\rightarrow n$ jets event generator, MEPJET, which allows to analyze arbitrary jet…
Power corrections to hadronic event shapes are estimated using a recently suggested relationship between perturbative and non-perturbative effects in QCD. The infrared cutoff dependence of perturbative calculations is related to…
Several methods to extract the strong coupling constant $\alpha_s$ by means of highly energetic jets in Deep-Inelastic Scattering are presented. The results from the various methods agree with one another and with the world average. The…
Collective behaviour of final-state hadrons, and multiparton interactions are studied in high-multiplicity $ep$ scattering at a centre-of-mass energy $\sqrt{s}=318$ GeV with the ZEUS detector at HERA. Two- and four-particle azimuthal…
The size of non-perturbative corrections to event shape observables is predicted to fall like a power of the inverse centre of mass energy. These power corrections are investigated for different observables from e+e-annihilation and…
The present status of our ongoing systematic study of the discovery potential of QCD-instanton induced events in deep-inelastic scattering at HERA is briefly reviewed. We emphasize our recent progress in predicting the cross-sections of…
New studies of hadronic event shape observables in e+ e- collisions between 13 and 183 GeV CM energy have enabled the running of alpha_s to be confirmed and the validity of non-perturbative power-law corrections to be investigated. A more…
For the study of deep inelastic scattering at HERA, the use of Jaquet-Blondel variables is advantageous in several respects. We calculate the complete leptonic ${\cal O}(\alpha)$ QED corrections for the reaction $ep \to eX$ in these…
We show that the `orthogonal' characteristics of the observed rapidity gaps and large forward energy flows in deep inelastic scattering at HERA, can be described within a single framework. Our Monte Carlo model is based on perturbative QCD…
A measurement is presented, using data taken with the H1 detector at HERA, of the contribution of diffractive interactions to deep-inelastic electron-proton scattering. The diffractive contribution to the proton structure function is…