Subjet distributions were measured in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 81.7 pb-1. Jets were identified using the kT cluster algorithm in the laboratory frame. Subjets were defined as jet-like substructures identified by a reapplication of the cluster algorithm at a smaller value of the resolution parameter ycut. Measurements of subjet distributions for jets with exactly two subjets for ycut=0.05 are presented as functions of observables sensitive to the pattern of parton radiation and to the colour coherence between the initial and final states. Perturbative QCD predictions give an adequate description of the data.
Recent results on subjet distributions from ZEUS are presented. The measured normalised cross sections were used to study the pattern of parton radiation. The comparison of the measurements with leading-logarithm parton-shower Monte Carlo models and perturbative QCD calculations shows a good agreement between data and predictions. Results on event-shape mean values and distributions are also presented. These measurements were used to test the predictions of the power-correction model for hadronisation. A universal value, within 10%, of the effective parameter alpha_0 of the model was obtained.
The subjet multiplicity has been measured in neutral current e+p interactions at Q**2 > 125 GeV**2 with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb-1. Jets were identified in the laboratory frame using the longitudinally invariant K_T cluster algorithm. The number of jet-like substructures within jets, known as the subjet multiplicity, is defined as the number of clusters resolved in a jet by reapplying the jet algorithm at a smaller resolution scale y_cut. Measurements of the mean subjet multiplicity, < n_sbj >, for jets with transverse energies E_T,jet >15 GeV are pre…
The internal structure of the jets produced in neutral current interactions for Q^2>125 GeV^2 has been studied using the subjet multiplicity with the ZEUS detector at HERA. Jets are identified in the laboratory frame by applying the longitudinally invariant k_T-cluster algorithm. Next-to-leading order QCD calculations have been obtained and compared to the data; a good agreement has been observed in the region where hadron-to-parton corrections are small, E_{T,jet}> 25 GeV. In this region, the strong coupling constant is extracted and the resulting value is alpha_s (M_Z)=0.1185 +/- 0.0016 (sta…
Besides structure function measurements and jet physics, there is a lively collection of more specific QCD analyses at HERA. In this contribution we present three-jet angular correlations and subjet distributions measured in ep collisions with the ZEUS detector. The angular correlations provide sensitivity to the color factors of the underlying gauge group and thus facilitate tests of basic properties of the strong interaction. The subjet distributions allow tests of the QCD radiation pattern within a jet in the perturbative regime.
Internal jet structure in dijet production in deep-inelastic scattering is measured with the H1 detector at HERA. Jets with transverse energies ET,Breit > 5 GeV are selected in the Breit frame employing k_perp and cone jet algorithms. In the kinematic region of squared momentum transfers 10 < Q2 <~ 120 GeV2 and x-Bjorken values 2.10^-4 <~ xBj <~ 8.10^-3, jet shapes and subjet multiplicities are measured as a function of a resolution parameter. Distributions of both observables are corrected for detector effects and presented as functions of the transverse jet energy and jet pseudo-rapidity. De…
Event shapes and jet shapes in neutral current deep inelastic scattering and photoproduction are studied with the H1 and ZEUS detectors at HERA. The measurements are compared to next-to-leading-order QCD calculations and Monte Carlo models. The strong coupling constant is determined from subjet multiplicities.
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 jets are used to select samples to study the dynamics of the subprocesses.
Jet substructure and differential cross sections for jets produced in the photoproduction and deep inelastic ep scattering regimes have been measured with the ZEUS detector at HERA using an integrated luminosity of 82.2 pb-1. The substructure of jets has been studied in terms of the jet shape and subjet multiplicity for jets with transverse energies Et(jet) > 17 GeV. The data are well described by the QCD calculations. The jet shape and subjet multiplicity are used to tag gluon- and quark-initiated jets. Jet cross sections as functions of Et(jet), jet pseudorapidity, the jet-jet scattering ang…
The substructure of jets has been studied in terms of the jet shape and subjet multiplicity and these quantities used to tag gluon- and quark-initiated jets. Cross sections are presented for gluon- and quark-tagged jets which exhibit the expected behaviour of the underlying parton dynamics. The value of alpha_s(M_Z) of alpha_s(M_Z) = 0.1176 +- 0.0009 (stat.) ^{+0.0009}_{-0.0026} (exp.) ^{+0.0091}_{-0.0072} (th.) was extracted from the measurements of jet shapes in deep inelastic scattering.
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 are presented for jets with transverse energies E_T(jet) > 14 GeV and pseudorapidities in the range -1 < eta(jet) < 2. Dijet cross sections are presented for events with a jet having E_T(jet) > 14 GeV and a second jet having E_T(jet) > 5 GeV. Measurements of the mean subjet multiplicity, <n_sbj>, of the inclusive jet sample are presented. Predictions based …
Results on the analysis of the hadronic final state in neutral current deep inelastic scattering at HERA are presented; recent results on inclusive single particle distributions, particle correlations and event shapes are highlighted.
Recent results from jet production in deep inelastic ep scattering at HERA are reviewed. The values of alpha_s(M_z) extracted from a QCD analysis of the data are presented.
Recent high precision measurements of deep inelastic diffractive scattering at HERA are presented in an increased region of phase space. Current models for diffractive photon dissociation are compared to the data.
Isolated hard photons have been measured with jets in Deep Inelastic Scattering using the ZEUS detector at HERA. Preliminary results for the cross sections are presented.
This contribution covers three recent results on deep-inelastic scattering at HERA: (i) new measurements of the proton longitudinal structure function $F_L$ from H1 and ZEUS experiments, (ii) a dedicated NC cross section measurement from ZEUS in the region of high Bjorken $x$, and (iii) preliminary combination results of all HERA inclusive data published up to now by H1 and ZEUS, taking into account the experimental correlations between measurements.
Recent measurements of jet cross sections in neutral-current and charged-current deep inelastic ep scattering are presented. The results of the QCD analyses on these measurements to determine the strong coupling constant are also reported.
In this paper an introduction to the physics of deep-inelastic scattering is given together with an account of some of the most recent results on the proton structure obtained in electron-- and positron--proton collisions at the HERA collider.
The substructure of jets produced in an exclusive and a charm-induced dijet sample in photoproduction and in charged and neutral current interactions has been studied with the ZEUS detector at HERA. Jets were identified using the longitudinally invariant k_T cluster algorithm in the laboratory frame. The substructure of jets has been studied in terms of the jet shape and subjet multiplicity. Comparisons between the dijet sample and the quark-induced samples allow an extraction of the jet substructure for gluons. Leading-logarithm parton-shower Monte Carlo calculations give a good description o…
Recent results on jet production in neutral current deep inelastic scattering and high energy photoproduction at the HERA electron-proton-collider are briefly reviewed. The results are compared to QCD expectations in NLO and $α_s$ determinations using these data are summarized.
This lecture contains a brief introduction to HERA and deep inelastic scattering (DIS), before going on to highlight some of the measurements of the hadronic final state in DIS performed by the H1 and ZEUS collaborations.
A measurement is presented of inelastic photo- and electroproduction of J/psi mesons in ep scattering at HERA. The data were recorded with the H1 detector in the period from 2004 to 2007. Single and double differential cross sections are determined and the helicity distributions of the J/psi mesons are analysed. The results are compared to theoretical predictions in the colour singlet model and in the framework of non-relativistic QCD. Calculations in the colour singlet model using a k_T factorisation ansatz are able to give a good description of the data, while colour singlet model calculatio…
Neutral-current and charged-current deep-inelastic scattering at very high four-momentum transfer squared (Q^2) have been studied in positron-proton collisions at center-of-mass energy 300 GeV using the ZEUS detector at HERA. An integrated luminosity of 47.7 $pb^{-1}$ was collected in the years 1994-1997. Differential cross sections are presented for $Q^2 > 400 GeV^2$ and compared to Standard Model predictions.
The azimuthal distribution of jets produced in the Breit frame in high-Q**2 deep inelastic e+p scattering has been studied with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb-1. The measured azimuthal distribution shows a structure that is well described by next-to-leading-order QCD predictions over the Q**2 range considered, Q**2>125 GeV**2.
The results from a recent analysis on beauty production in deep inelastic scattering at HERA using decays into electrons from the ZEUS collaboration are presented. The fractions of events containing b quarks were extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. Total and differential cross sections were measured and compared with next-to-leading-order QCD calculations. The beauty contribution to the proton structure function F_2 was extracted from the double-differential cross sections.
Several methods to extract the strong coupling constant $α_s$ 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 errors are competetive to those achieved in $α_s$ determinations in other processes such as proton--anti-proton scattering.
Two-jet production in deep-inelastic electron-proton scattering has been studied for $160<Q^2<1280$~GeV$^2$, $0.01<x<0.1$ and $0.04<y<0.95$ with the ZEUS detector at HERA. The kinematic properties of the jets and the jet production rates are presented. The partonic scaling variables of the two-jet system and the rate of two-jet production are compared to perturbative next-to-leading order QCD calculations.
The $J/ψ$ decay angular distributions have been measured in inelastic photoproduction in $e p$ collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 $pb^{-1}$. The range in photon-proton centre-of-mass energy, $W$, was 50 $< W <$ 180 $GeV$. The $J/ψ$ mesons were identified through their decay into muon pairs. The polar and azimuthal angles of the $μ^+$ were measured in the $J/ψ$ rest frame and compared to theoretical predictions at leading and next-to-leading order in QCD.
Recent results from the \emph{ep} collier HERA are presented. Inclusive dijet cross sections have been measured in neutral current deep inelastic scattering, for virtualities of the exchanged boson in the range $125 < Q^{2} < 20\,000\; GeV^{2}$ and in photoproduction, $Q^{2} \sim 0 GeV^{2}$. The measurements are compared to perturbative QCD calculations at next-to-leading order.
The production of $D^{*\pm}$ mesons in deep inelastic $ep$ scattering has been measured for exchanged photon virtualities $ 5<Q^2<1000 \gev^2 $, using an integrated luminosity of 363 pb$^{-1}$ with the ZEUS detector at HERA. Differential cross sections have been measured and compared to next-to-leading-order QCD calculations. The cross-sections are used to extract the charm contribution to the proton structure functions, expressed in terms of the reduced charm cross section, $σ_{\rm red}^{c\bar{c}}$. Theoretical calculations based on fits to inclusive HERA data are compared to the results.
The measurement of the beauty quark production cross section in deep inelastic scattering with the ZEUS detector at HERA is presented. The cross section for beauty quarks, measured in the kinematic range $Q^2 > 2$ GeV$^2$ and $0.05 < y < 0.7$, and for events with at least one muon and one jet in the Breit frame, is somewhat above the next-to-leading order (NLO) QCD prediction, but in agreement within the experimental and theoretical uncertainties.
Dijet cross sections in neutral current deep inelastic ep scattering have been measured in the range $10 < \Q2 < 10^4$ GeV$^2$ with the ZEUS detector at HERA using an integrated luminosity of 38.4 pb$^{-1}$. The cross sections, measured in the Breit frame using the $\kt$ jet algorithm, are compared with next-to-leading-order perturbative QCD calculations using proton parton distribution functions. The uncertainties of the QCD calculations have been studied. The predictions are in reasonable agreement with the measured cross sections over the entire kinematic range.
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 (NLO) calculations. They also provide the opportunity to test the consistency of the gluon distribution in the proton as extracted from (mainly) inclusive DIS measurements. Comparison of the cross sections with NLO enables accurate extractions of the strong coupling constant, $α_s$, to be made, several of which are reported here.
Recent results on inclusive D^0 and D^{*+-} production in deeply inelastic ep scattering at sqrt(s)=301 GeV are summarized. The data have been collected by the H1 and ZEUS experiments at HERA. The total and the differential cross sections are discussed in the framework of LO and NLO QCD predictions. The data exhibit clear evidence for boson gluon fusion dominating open heavy flavor production in the kinematic range currently explored at HERA. The measurements of F_2^{cc}(x,Q^2) at small Bjorken x are presented. The prospects for future analyses of open charm and beauty production including det…
A measurement is presented of single- and double-differential dijet cross sections in diffractive deep-inelastic $ep$ scattering at HERA using data collected by the H1 experiment corresponding to an integrated luminosity of 290 pb^{-1}. The investigated phase space is spanned by the photon virtuality in the range of 4<Q^{2}<100 GeV^{2} and by the fractional proton longitudinal momentum loss x_pom<0.03. The resulting cross sections are compared with next-to-leading order QCD predictions based on diffractive parton distribution functions and the value of the strong coupling constant is extracted…
Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastic ep scattering have been measured over a large kinematical region. The evolution with $W$ and $Q^2$ of the multiplicity distribution and of the multiplicity moments in pseudorapidity domains of varying size is studied in the current fragmentation region of the hadronic centre-of-mass frame. The results are compared with data from fixed target lepton-nucleon interactions, $e^+e^-$ annihilations and hadron-hadron collisions as well as with expectations from QCD based parton models. Fits to the Negative Bi…
The universality and scaling behaviour of hadronisation have been investigated in semi-inclusive neutral current deep inelastic ep scattering; specifically the multiplicity and scaled momentum spectra of charged hadrons have been measured and analysed. The measurements are performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic centre-of-mass frame. The data collected at the HERA ep collider by the H1 and ZEUS experiments are compared with similar measurements obtained in e+e- annihilation and with previous ep measurements as well as w…
Results from the H1 and ZEUS experiments at HERA on deep inelastic scattering are reviewed. The data lead to a consistent picture of a steep rise in the F_2 structure function and in the gluon density within the proton. Important new information on the partonic structure of diffraction is emerging from H1 and ZEUS. The space-like region in which the weak and electromagnetic interactions become of equal strength is being explored for the first time. A possible excess of events at high x and Q^2 compared to the expectations of the Standard Model has been observed in both experiments.
Diffractive production of D*+-(2010) mesons in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 44.3 pb-1. Diffractive charm production is identified by the presence of a large rapidity gap in the final state of events in which a D*+-(2010) meson is reconstructed in the decay channel D*+ -> (D0 -> K-pi+) pi+ (+ charge conjugate). Differential cross sections when compared with theoretical predictions indicate the importance of gluons in such diffractive interactions.
The production of neutral strange hadrons is investigated using deep-inelastic scattering events measured with the H1 detector at HERA. The measurements are made in the phase space defined by the negative four-momentum transfer squared of the photon 2 < Q^2 < 100 GeV^2 and the inelasticity 0.1 < y < 0.6. The K_s and Lambda production cross sections and their ratios are determined. K_s production is compared to the production of charged particles in the same region of phase space. The Lambda - anti-Lambda asymmetry is also measured and found to be consistent with zero. Predictions of leading or…
Several recent measurements of charmed hadron production in deep inelastic scattering at HERA are reviewed. Cross sections for the production of D mesons were measured and compared to NLO QCD predictions. The charm contribution to the inclusive structure function F_{2} was extracted and compared to previous measurements and theoretical predictions. The reconstruction of decays with a neutral strange hadron in the final state allowed the measurement of charm production to be extended into the low transverse momentum region. The fraction of c quarks hadronising into Lambda_{c}^{+} baryons was ex…
Forward jet cross sections have been measured in neutral current deep inelastic scattering at low Bjorken-x with the ZEUS detector at HERA using an integrated luminosity of ${81.8 \rm pb}^{-1}$. Measurements are presented for inclusive forward jets as well as for forward jets accompanied by a dijet system. The explored phase space, with jet pseudorapidity up to 4.3 is expected to be particularly sensitive to the dynamics of QCD parton evolution at low x. The measurements are compared to fixed-order QCD calculations and to leading-order parton-shower Monte Carlo models.
Preliminary H1 results on dedicated searches for QCD instanton induced processes in DIS are presented. The investigations are based on the expected characteristics of their hadronic final state. Searches were performed in the kinematical region x > 0.001, 0.1 < y < 0.6 and the polar angle of scattered positron greater than 156 degrees.
The charged multiplicity distributions and the mean charged multiplicity have been investigated in inclusive neutral current deep inelastic $ep$ scattering with the ZEUS detector at HERA, using an integrated luminosity of 38.6 pb$^{-1}$. The measurements were performed in the current region of the Breit frame, as well as in the current fragmentation region of the hadronic centre-of-mass frame. The KNO-scaling properties of the data were investigated and the energy dependence was studied using different energy scales. The data are compared to results obtained in $\epem$ collisions and to previo…
The average charged track multiplicity and the normalised distribution of the scaled momentum, $\xp$, of charged final state hadrons are measured in deep-inelastic $\ep$ scattering at high $Q^2$ in the Breit frame of reference. The analysis covers the range of photon virtuality $100 < Q^2 < 20 000 \GeV^{2}$. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher $Q^{2}$ and to the full range of $\xp$. The results are compared with $e^+e^-$ annihilation data and with various calculations b…
Charged particle production in deep-inelastic ep scattering is measured with the H1 detector at HERA. The kinematic range of the analysis covers low photon virtualities, 5 < Q^2 < 100 GeV^2, and small values of Bjorken-x, 10^{-4} < x < 10^{-2}. The analysis is performed in the hadronic centre-of-mass system. The charged particle densities are measured as a function of pseudorapidity (eta^*) and transverse momentum (p_T^*) in the range 0< η^* < 5 and 0< p_T^* < 10$ GeV differentially in x and Q^2. The data are compared to predictions from different Monte Carlo generators implementing various op…
We review and compare the reconstruction methods of the inclusive deep inelastic scattering variables used at HERA. We introduce a new prescription, the $Σ$ method, which allows to measure the structure function of the proton $F_2(x,Q^2)$ in a large kinematic domain, and in particular in the low x-low$Q^2$ region, with small systematic errors and small radiative corrections. A detailed comparison between the $Σ$ method and the other methods is shown. Extensions of the $Σ$ method are presented. The effect of QED radiation on the kinematic reconstruction and on the structure function measurement…
The production of dijets is measured in diffractive deep-inelastic scattering at HERA. The data were recorded with the H1 detector at DESY in the years 2003-2007. Diffractive events are selected by requiring a gap in the rapidity distribution of the hadronic systen, where no particles are produced. Two jets are selected with transverse momenta in the hadronic-centre-of-mass system larger than 4 and 5.5GeV, respectively. Cross sections are measured single- and doubledifferentially in various kinematic quantities. The data are found to be in good agreement with NLO QCD calculations based on diff…
Inclusive KsKs production in deep inelastic ep scattering at HERA has been studied with the ZEUS detector using an integrated luminosity of 120 pb-1. Two states are observed at masses of 1537{+9}{-8} MeV and 1726{+-7} MeV, as well as an enhancement around 1300 MeV. The state at 1537 MeV is consistent with the well established f'2(1525). The state at 1726 MeV may be the glueball candidate f0(1710). However, it's width of 38{+20}{-14} MeV is narrower than 125{+-10} MeV observed by previous experiments for the f0(1710).
Inclusive production of D*+/- (2010) mesons in deep inelastic scattering has been measured using e+p and e-p data obtained with the ZEUS detector at HERA using integrated luminosities of 16.7 and 65.2 pb-1, respectively. The decay channel D*+/- -> D0 pi+ with D0 -> K- pi+ and corresponding antiparticle decays were used to identify D*+/- mesons. The D*+/- cross sections in e-p and e+p interactions agree with NLO QCD predictions, although the D*+/- cross section in e-p is slightly higher than that in e+p.
Charged particle production in neutral current deep inelastic scattering (DIS) has been studied using the ZEUS detector.The evolution of the mean multiplicities, scaled momenta and transverse momenta in $Q^2$ and $x$ for $ 10 < Q^2 < 5120 GeV^2$ and $x > 6\times 10^{-4}$ has been investigated in the current and target fragmentation regions of the Breit frame. Distributions in the target region, using HERA data for the first time, are compared to distributions in the current region. Predictions based on MLLA and LPHD are inconsistent with the data.
H1 and ZEUS have published single-differential cross sections for inclusive D^{*\pm}-meson production in deep-inelastic ep scattering at HERA from their respective final data sets. These cross sections are combined in the common visible phase-space region of photon virtuality Q2 > 5 GeV2, electron inelasticity 0.02 < y < 0.7 and the D^{*\pm} meson's transverse momentum pT (D^*) > 1.5 GeV and pseudorapidity |eta(D^*)| < 1.5. The combination procedure takes into account all correlations, yielding significantly reduced experimental uncertainties. Double-differential cross sections d2s /dQ2dy are …
A search for QCD-instanton-induced events in deep inelastic ep scattering has been performed with the ZEUS detector at the HERA collider, using data corresponding to an integrated luminosity of 38 pb^{-1}. A kinematic range defined by cuts on the photon virtuality, Q^2 > 120 GeV^2, and on the Bjorken scaling variable, x > 10^{-3}, has been investigated. The QCD-instanton induced events were modelled by the Monte Carlo generator QCDINS. A background-independent, conservative 95% confidence level upper limit for the instanton cross section of 26 pb is obtained, to be compared with the theoretica…
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 at a centre-of-mass energy of 300 GeV. They cover the kinematic range 2.7 < Q^2 < 30000 GeV2 and 6.10^-5 < x < 0.65. The variation of F2 with x and Q2 is well described by next-to-leading-order perturbative QCD as implemented in the DGLAP evolution equations.
A first measurement is presented of the charge asymmetry in the hadronic final state from the hard interaction in deep-inelastic ep neutral current scattering at HERA. The measurement is performed in the range of negative squared four momentum transfer 100<Q^2<8,000 GeV^2. The difference between the event normalised distributions of the scaled momentum, x_p, for positively and negatively charged particles, measured in the current region of the Breit frame, is studied together with its evolution as a function of Q. The results are compared to Monte Carlo models at the hadron and parton level.
The process of charm quark fragmentation is studied using $D^{*\pm}$ meson production in deep-inelastic scattering as measured by the H1 detector at HERA. Two different regions of phase space are investigated defined by the presence or absence of a jet containing the $D^{*\pm}$ meson in the event. The parameters of fragmentation functions are extracted for QCD models based on leading order matrix elements and DGLAP or CCFM evolution of partons together with string fragmentation and particle decays. Additionally, they are determined for a next-to-leading order QCD calculation in the fixed flavo…
In deep inelastic neutral current scattering of positrons and protons at the center of mass energy of 300 GeV, we observe, with the ZEUS detector, events with a high energy neutron produced at very small scattering angles with respect to the proton direction. The events constitute a fixed fraction of the deep inelastic, neutral current event sample independent of Bjorken $x$ and $Q^2$ in the range $ 3 \cdot 10^{-4} < \xbj < 6\cdot 10^{-3}$ and $10 < Q^2 <100$~GeV$^2$.
Deep-inelastic positron-proton scattering events at low photon virtuality Q^2 with a forward jet, produced at small angles with respect to the proton beam, are measured with the H1 detector at HERA. A subsample of events with an additional jet in the central region is also studied. For both samples differential cross sections and normalised distributions are measured as a function of the azimuthal angle difference, Delta phi, between the forward jet and the scattered positron. The sensitivity to QCD evolution mechanisms is tested by comparing the data to predictions of Monte Carlo generators b…
Inclusive KsKs production in deep inelastic ep scattering at HERA has been studied with the ZEUS detector using an integrated luminosity of 120 pb-1. Two states are observed at masses of 1537 (+9)(-8) MeV and 1726 +- 7 MeV, as well as an enhancement around 1300 MeV. The state at 1537 MeV is consistent with the well established f2'(1525). The state at 1726 MeV may be the glueball candidate f0(1710). However, it's width of 38 (+20)(-14) MeV is narrower than 125 +- 10 MeV observed by previous experiments for the f0(1710).
Measurements of differential cross sections for deep inelastic ep neutral-current (NC) and charged-current (CC) reactions are presented using data taken during the 1994-97 e^+p and the 1998-99 e^-p running periods. The structure function xF_3 has been extracted combining NC e^-p and e^+p data sets. Both the measured cross sections and xF_3 are well described by the standard model predictions using standard PDF's.
