Measurements of the cross sections for charged current deep inelastic scattering in e-p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb-1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections dsigma/dQ2, dsigma/dx and dsigma/dy are presented for Q2>200 GeV2. The double-differential cross-section d2sigma/dxdQ2 is presented in the kinematic range 280<Q2<30000 GeV2 and 0.015<x<0.65. The measured cross sections are compared with the predictions of the Standard Model.
Values of the reduced cross section with detailed statistical and systematic errors.. The first DSYS is the uncorrelated systematic error and the second is the calorimeter energy scale uncertainty which has significant correlationS between cross section bins.
The neutral current e+/-p cross section has been measured up to values of Bjorken x of approximately 1 with the ZEUS detector at HERA using an integrated luminosity of 187 inv. pb of e-p and 142 inv. pb of e+p collisions at sqrt(s) = 318GeV. Differential cross sections in x and Q2, the exchanged boson virtuality, are presented for Q2 geq 725GeV2. An improved reconstruction method and greatly increased amount of data allows a finer binning in the high-x region of the neutral current cross section and leads to a measurement with much improved precision compared to a similar earlier analysis. The measurements are compared to Standard Model expectations based on a variety of recent parton distribution functions.
Double differential cross section for Q^2=725 GeV^2.
Double differential cross section for Q^2=875 GeV^2.
Double differential cross section for Q^2=1025 GeV^2.
The reduced cross sections for $e^{+}p$ deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, $318$, $251$ and $225$ GeV. The cross sections, measured double differentially in Bjorken $x$ and the virtuality, $Q^2$, were obtained in the region $0.13\ \leq\ y\ \leq\ 0.75$, where $y$ denotes the inelasticity and $5\ \leq\ Q^2\ \leq\ 110$ GeV$^2$. The proton structure functions $F_2$ and $F_L$ were extracted from the measured cross sections.
The reduced cross section for the reaction E+ P --> E+ X at a centre-of-mass energy 318 GeV and Q^2=7 GeV^2 for the central-vertex region. The (sys) error shown in the table is the total systematic uncertainty, excluding the normalisation uncertainties shown separately below.
The reduced cross section for the reaction E+ P --> E+ X at a centre-of-mass energy 318 GeV and Q^2=9 GeV^2 for the central-vertex region. The (sys) error shown in the table is the total systematic uncertainty, excluding the normalisation uncertainties shown separately below.
The reduced cross section for the reaction E+ P --> E+ X at a centre-of-mass energy 318 GeV and Q^2=12 GeV^2 for the central-vertex region. The (sys) error shown in the table is the total systematic uncertainty, excluding the normalisation uncertainties shown separately below.
The cross sections for inelastic photoproduction of J/psi and psi' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 38.0 pb-1. The events were required to have 0.1 < z < 0.9 and 50 < W < 180 GeV, where z is the fraction of the incident photon energy carried by the J/psi in the proton rest frame and W is the photon-proton centre-of-mass energy. The psi' to J/psi cross-section ratio was measured in the range 0.55 < z < 0.9. The J/psi data, for various ranges of transverse momentum, are compared to theoretical models incorporating colour-singlet and colour-octet matrix elements. Predictions of a next-to-leading-order colour-singlet model give a good description of the data, although there is a large normalisation uncertainty. The J/psi helicity distribution for z > 0.4 is compared to leading-order QCD predictions.
Measurment of the total cross section, with various PT thresholds, in the high Z > 0.9 region.
Ratio of cross section for PSI(2S) to J/PSI production. as a function of PT. Statistical errors only.
Ratio of cross section for PSI(2S) to J/PSI production. as a function of W. Statistical errors only.
A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised ep scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q^2, and in Bjorken x. The combination method used takes the correlations of systematic uncertainties into account, resulting in an improved accuracy. The combined data are the sole input in a NLO QCD analysis which determines a new set of parton distributions HERAPDF1.0 with small experimental uncertainties. This set includes an estimate of the model and parametrisation uncertainties of the fit result.
Combined reduced cross section data and F2 for Neutral Current E+ P scattering at Q**2=0.045 GeV**2.
Combined reduced cross section data and F2 for Neutral Current E+ P scattering at Q**2=0.065 GeV**2.
Combined reduced cross section data and F2 for Neutral Current E+ P scattering at Q**2=0.085 GeV**2.
Cross sections for e^-p neutral current deep inelastic scattering have been measured at a centre-of-mass energy of 318 GeV using an integrated luminosity of 15.9 pb^-1 collected with the ZEUS detector at HERA. Results on the double-differential cross-section d^2s/dxdQ^2 in the range 185 < Q^2 < 50000 GeV^2 and 0.0037 < x < 0.75, as well as the single-differential cross-sections ds/dQ^2, ds/dx and ds/dy for Q^2 > 200 GeV^2, are presented. To study the effect of Z-boson exchange, ds/dx has also been measured for Q^2 > 10000 GeV^2. The structure function xF_3 has been extracted by combining the e^-p results presented here with the recent ZEUS measurements of e^+p neutral current deep inelastic scattering. All results agree well with the predictions of the Standard Model.
Differential cross section DSIG/DQ**2.
Differential cross section DSIG/DX for two Q**2 regions.
Differential cross section DSIG/DY.
Deep inelastic $e~-p$ scattering has been studied in both the charged-current (CC) and neutral-current (NC) reactions at momentum transfers squared, $Q~2$, between 400 GeV$~2$ and the kinematic limit of 87500 GeV$~2$ using the ZEUS detector at the HERA $ep$ collider. The CC and NC total cross sections, the NC to CC cross section ratio, and the differential cross sections, $ d\sigma/dQ~2 $, are presented. For $Q~2 \simeq M_W~2$, where $M_W$ is the mass of the $W$ boson, the CC and NC cross sections have comparable magnitudes, demonstrating the equal strengths of the weak and electromagnetic interactions at high $Q~2$. The $Q~2$ dependence of the CC cross section determines the mass term in the CC propagator to be $M_{W} = 76 \pm 16 \pm 13$GeV.
Data requested from authors.
Neutral current cross sections.
Integrated neutral and charged current cross sections.
The photoproduction of $D^{*\pm}$ mesons has been measured with the ZEUS detector at HERA at three different ep centre-of-mass energies, $\sqrt{s}$, of 318, 251 and 225 GeV. For each data set, $D^*$ mesons were required to have transverse momentum, $p_T^{D^*}$, and pseudorapidity, $\eta^{D^*}$, in the ranges $1.9 < p_T^{D^*} < 20$ GeV and $|\eta^{D^*}|<1.6$. The events were required to have a virtuality of the incoming photon, $Q^2$, of less than 1 GeV$^2$. The dependence on $\sqrt{s}$ was studied by normalising to the high-statistics measurement at $\sqrt{s} =318$ GeV. This led to the cancellation of a number of systematic effects both in data and theory. Predictions from next-to-leading-order QCD describe the $\sqrt{s}$ dependence of the data well.
The cross sections for the production of D*+- mesons normalised to the HER data sample.
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 $\sqrt{s} = 318 \;\mathrm{GeV}$, corresponding to an integrated luminosity of $326 \;\mathrm{pb}^{-1}$. A measurement of jet cross sections in the laboratory frame was made in a fiducial region corresponding to photon virtuality $10 \;\mathrm{GeV}^2 < Q^2 < 350 \;\mathrm{GeV}^2$, inelasticity $0.04 < y < 0.7$, outgoing lepton energy $E_e > 10 \;\mathrm{GeV}$, lepton polar angle $140^\circ < \theta_e < 180^\circ$, jet transverse momentum $2.5 \;\mathrm{GeV} < p_\mathrm{T,jet} < 30 \;\mathrm{GeV}$, and jet pseudorapidity $-1.5 < \eta_\mathrm{jet} < 1.8$. Jets were reconstructed using the $k_\mathrm{T}$ algorithm with the radius parameter $R = 1$. The leading jet in an event is defined as the jet that carries the highest $p_\mathrm{T,jet}$. Differential cross sections, $d\sigma/d\Delta\phi$, were measured as a function of the azimuthal correlation angle in various ranges of leading-jet transverse momentum, photon virtuality and jet multiplicity. Perturbative calculations at $\mathcal{O}(\alpha_{s}^2)$ accuracy successfully describe the data within the fiducial region, although a lower level of agreement is observed near $\Delta\phi \rightarrow \pi$ for events with high jet multiplicity, due to limitations of the perturbative approach in describing soft phenomena in QCD. The data are equally well described by Monte Carlo predictions that supplement leading-order matrix elements with parton showering.
<b>Note: in the paper, uncertainties are given in relative terms. The HEPData table contains absolute numbers. The original data file, containing relative uncertainties as in the paper, is available via the 'Resources' button above.</b> Inclusive measurement of the differential cross sections, $d\sigma/d\Delta\phi$, as obtained from the data, ARIADNE MC simulations, and perturbative calculations at $\mathcal{O}(\alpha_{s})$ and $\mathcal{O}(\alpha_{s}^{2})$ accuracy. The effect of initial- and final-state radiation has been corrected in data, based on a simulation study performed in the RAPGAP framework. The quantities $\delta_\mathrm{stat}$ and $\delta_\mathrm{syst}$ represent the statistical and systematic uncertainties relative to the central value, respectively. The uncertainty in the luminosity measurement ($1.9\%$) is not included in these values. The quantities $\delta(\mathcal{O}(\alpha_{s}^{k}))$ represent the combined uncertainty of the scale dependence in the calculation and the model dependence in the hadronisation correction in the $\mathcal{O}(\alpha_{s}^{k})$ calculations.
<b>Note: in the paper, uncertainties are given in relative terms. The HEPData table contains absolute numbers. The original data file, containing relative uncertainties as in the paper, is available via the 'Resources' button above.</b> Differential cross sections, $d\sigma/d\Delta\phi$, in the $p_{T,jet}^{lead}$ region of $2.5 \;\mathrm{GeV} < p_{T,jet}^{lead} < 7 \;\mathrm{GeV}$ for $N_{jet} \geq 1$, as obtained from the data, ARIADNE MC simulations, and perturbative calculations at $\mathcal{O}(\alpha_{s})$ and $\mathcal{O}(\alpha_{s}^{2})$ accuracy. Other details are as in the caption to Table 1.
<b>Note: in the paper, uncertainties are given in relative terms. The HEPData table contains absolute numbers. The original data file, containing relative uncertainties as in the paper, is available via the 'Resources' button above.</b> Differential cross sections, $d\sigma/d\Delta\phi$, in the $p_{T,jet}^{lead}$ region of $2.5 \;\mathrm{GeV} < p_{T,jet}^{lead} < 7 \;\mathrm{GeV}$ for $N_{jet} \geq 2$, as obtained from the data, ARIADNE MC simulations, and perturbative calculations at $\mathcal{O}(\alpha_{s})$ and $\mathcal{O}(\alpha_{s}^{2})$ accuracy. Other details are as in the caption to Table 1.
The total photoproduction cross section is determined from a measurement of electroproduction with the ZEUS detector at HERA. The Q 2 values of the virtual photons are in the range 10 −7 < Q 2 <2×10 −2 GeV 2 . The γp total cross section in the γp centre of mass energy range 186–233 GeV is 154 ± 16 (stat.) ± 32 (syst.) μ b.
Scattered electron in range 10 to 16 GeV.
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