Meade Derrick

New Jersey City University · Department of Art

The production of D *± mesons in deep inelastic ep scattering has been measured for exchanged photon virtualities 5 < Q 2 < 1000 GeV2, 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 extrac...

The production of D 0, D *+, D +, \( D_s^{+} \) and \( \Lambda_c^{+} \) charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb−1. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to...

A bstract Charm production in deep inelastic ep scattering was measured with the ZEUS detector using an integrated luminosity of 354 pb ⁻¹ . Charm quarks were identified by reconstructing D ± mesons in the D ± → K ∓ π ± π ± decay channel. Lifetime information was used to reduce combinatorial background substantially. Differential cross sections wer...

Measurements of neutral current cross sections for deep inelastic scattering in e(+)p collisions at HERA with a longitudinally polarized positron beam are presented. The single-differential cross-sections d sigma=dQ(2), d sigma=dx and d sigma=dy and the reduced cross section (sigma) over tilde are measured in the kinematic region Q(2) >185 GeV2 and...

Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections \(\sigma_{\rm red}^{c\bar{c}}\) for charm production are obtained in the kinematic range of photon virtuality 2.5≤Q 2≤2000 GeV2 and Bjorken scaling variable 3⋅10−5≤x≤5⋅10−2. The combin...

The cross sections for inelastic photoproduction of J/ψ and ψ′ mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb−1 collected in the period 1996–2007. The ψ′ to J/ψ cross section ratio was measured in the range 0.55 < z < 0.9 and 60 < W < 190 GeV as a function of W, z and p T . Here W...

The production of Z0 bosons in the reaction ep -> eZ0p*, where p* stands for a proton or a low-mass nucleon resonance, has been studied in ep collisions at HERA using the ZEUS detector. The analysis is based on a data sample collected between 1996 and 2007, amounting to 496 pb-1 of integrated luminosity. The Z0 was measured in the hadronic decay mo...

A search for single-top production, $ep \rightarrow etX$, has been performed with the ZEUS detector at HERA using data corresponding to an integrated luminosity of $0.37\fbi$. No evidence for top production was found, consistent with the expectation from the Standard Model. Limits were computed for single-top production via flavour changing neutral...

Measurements of the cross sections for charged current deep inelastic scattering in e + p collisions with a longitudinally polarised positron beam are presented. The measurements are based on a data sample with an integrated luminosity of 132pb−1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318GeV. The total cross section...

The production of isolated high-energy photons accompanied by jets has been measured in deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of . Measurements were made for exchanged photon virtualities, , in the range 10 to . The photons were measured in the transverse-energy and pseudorapidity ranges and , a...

A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy sqrt(s) = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertain...

A search for first-generation leptoquarks was performed in electron-proton and positron-proton collisions recorded with the ZEUS detector at HERA in 2003–2007 using an integrated luminosity of 366 pb-1. Final states with an electron and jets or with missing transverse momentum and jets were analyzed, searching for resonances or other deviations fro...

Inclusive-jet cross sections have been measured in the reaction ep->e+jet+X for photon virtuality Q2 < 1 GeV2 and gamma-p centre-of-mass energies in the region 142 < W(gamma-p) < 293 GeV with the ZEUS detector at HERA using an integrated luminosity of 300 pb-1. Jets were identified using the kT, anti-kT or SIScone jet algorithms in the laboratory f...

Three-jet production in deep inelastic ep scattering and photoproduction was investigated with the ZEUS detector at HERA using an integrated luminosity of up to 127 pb-1. Measurements of differential cross sections are presented as functions of angular correlations between the three jets in the final state and the proton-beam direction. These corre...

Scaled momentum distributions for the strange hadrons \( K_{\text{S}}^0 \) and \( \Lambda /\bar{\Lambda } \) were measured in deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 330 pb−1. The evolution of these distributions with the photon virtuality, Q 2, was studied in the kinematic region 10 < Q 2 < 40...

A search for single-top production, ep→etX, has been made with the ZEUS detector at HERA using an integrated luminosity of . Events from both the leptonic and hadronic decay channels of the W boson resulting from the decay of the top quark were sought. For the leptonic mode, the search was made for events with isolated high-energy leptons and signi...

The exclusive electroproduction of two pions in the mass range 0.4 < M{\pi}{\pi} < 2.5 GeV has been studied with the ZEUS detector at HERA using an integrated luminosity of 82 pb-1. The analysis was carried out in the kinematic range of 2 < Q2 < 80 GeV2, 32 < W < 180 GeV and |t| < 0.6 GeV2, where Q2 is the photon virtuality, W is the photon-proton...

A search for single-top production, $ep \rightarrow etX$, has been performed with the ZEUS detector at HERA using data corresponding to an integrated luminosity of $0.37\fbi$. No evidence for top production was found, consistent with the expectation from the Standard Model. Limits were computed for single-top production via flavour changing neutral...

Scaled momentum distributions for the strange hadrons K0s and Lambda/bar Lambda were measured in deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 330 pb-1. The evolution of these distributions with the photon virtuality, Q2, was studied in the kinematic region 10<Q2<40000 GeV2 and 0.001<x<0.75, where x i...

The exclusive photoproduction reaction gamma p -> Upsilon(1S) p has been studied with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 468 pb^-1. The measurement covers the kinematic range 60<W<220 GeV and Q^2<1 GeV^2, where W is the photon-proton centre-of-mass energy and Q^2 is the photon virtuality. The exponential sl...

Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 $pb^{-1}$. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance o...

The energy dependence of the photon-proton total cross section, sigma(gamma p)(tot), was determined from e(+) p scattering data collected with the ZEUS detector at HERA at three values of the center-of-mass energy, W, of the gamma p system in the range 194 < W < 296 GeV. This is the first determination of the W dependence of sigma(gamma p)(tot) fro...

The production of beauty quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared Q 2>10GeV2, using an integrated luminosity of 363 pb−1. The beauty events were identified using electrons from semileptonic b decays with a transverse momentum 0.9 < pTe < 80.9 < p_{T}^{e} < 8GeV and pseudorapidity...

A study of events containing two tau leptons with high transverse momentum has been performed with the ZEUS detector at HERA, using a data sample corresponding to an integrated luminosity of 0.33 fb(-1). The tau candidates were identified from their decays into electrons, muons or hadronic jets. The number of tau-pair candidates has been compared w...

Single- and double-differential inclusive dijet cross sections in neutral current deep inelastic ep scattering have been measured with the ZEUS detector using an integrated luminosity of 374pb−1. The measurement was performed at large values of the photon virtuality, Q 2, between 125 and 20 000GeV2. The jets were reconstructed with the k T cluster...

Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 120 pb−1. The hadronic decay channels D + → K S 0 π +, Λ c + → pK S 0 and Λ c + → Λπ +, and their charge conjugates, were reconstructed. The presence of a neutral strange hadron in the final state reduces the combin...

For the first time, differential inclusive-jet cross sections have been measured in neutral current deep inelastic ep scattering using the anti-kT and SIScone algorithms. The measurements were made for boson virtualities Q2>125 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 82 pb−1 and the jets were identified in the Breit fr...

ZEUS inclusive diffractive-cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are...

Charged particle production has been studied in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 0.44 fb−1. Distributions of scaled momenta in the Breit frame are presented for particles in the current fragmentation region. The evolution of these spectra with the photon virtuality, Q 2, i...

ZEUS inclusive diffractive cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to costrain the gluon density. Predictions based on the extracted parton densities are...

Beauty production in deep inelastic scattering with events in which a muon and a jet are observed in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114pb−1. The fraction of events with beauty quarks in the data was determined using the distribution of the transverse momentum of the muon relative t...

The proton-dissociative diffractive photoproduction of J/ψ mesons has been studied in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb−1. The cross section is presented as a function of the photon-proton centre-of-mass energy and of the squared four-momentum transfer at the proton vertex. The results are compare...

Differential cross sections for dijet photoproduction and this process in association with a leading neutron, e(+) + p -> e(+) + jet + jet + X (+n), have been measured with the ZEUS detector at HERA using an integrated luminosity of 40 pb(-1). The fraction of dijet events with a leading neutron was studied as a function of different jet and event v...

A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e±p scattering at HERA during the period 1994-2000. The data span six orders of magnitude in negative four-momentum-transfer squared, Q2, and in Bjorken x. The combination method used takes...

Journal article Temporary entry (new)

A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e ± p 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 tak...

Internal report | Preprint

The production of charm and beauty quarks in ep interactions has been measured with the ZEUS detector at HERA for squared four-momentum exchange Q 2>20 GeV2, using an integrated luminosity of 126 pb−1. Charm and beauty quarks were identified through their decays into muons. Differential cross sections were measured for muon transverse momenta \(p_{...

Charged particle production has been studied in deep inelastic scattering (DIS) using an integrated luminosity of about 0.44 fb −1 taken with the ZEUS detector at HERA. The fragmentation properties of the struck quark in deep inelastic scattering have been investigated in the current fragmentation region of the Breit frame as a function of the exch...

For the first time, differential inclusive-jet cross sections have been measured in neutral current deep inelastic ep scattering using the anti-kT and SIScone algorithms. The measurements were made for boson virtualities Q2>125 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 82 pb−1 and the jets were identified in the Breit fr...

A combination is presented of the inclusive deep inelastic cross sections measured by the H1 and ZEUS Collaborations in neutral and charged current unpolarised e ± p 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 ta...

Charm production in deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The hadronic decay channels D + --> K S 0 pi +, Lambda c + --> pK S 0 and Lambda c + --> Lambda pi +, and their charge conjugates, were reconstructed. The presence of a neutral strange hadron in the final state...

A search is performed for Higgs bosons decaying into invisible final states, produced in association with a Z0 boson in e+e- collisions at energies between 183 and 209 GeV. The search is based on data samples collected by the OPAL detector at LEP corresponding to an integrated luminosity of about 660 pb-1. The analysis aims to select events contain...

The reduced cross sections for ep deep inelastic scattering have been measured with the ZEUS detector at HERA at three different centre-of-mass energies, 318, 251 and 225 GeV. From the cross sections, measured double differentially in Bjorken x and the virtuality, Q 2, the proton structure functions FL and F2 have been extracted in the region 5×10−...

A search for events containing an isolated electron or muon and missing transverse momentum produced in e ± p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994–2007 and correspond to an integrated luminosity of 0.98 fb−1. The observed event yields are in good overall agreement with the Standard M...

A search for events containing an isolated electron or muon and missing transverse momentum produced in e ±p collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994–2007 and correspond to an integrated luminosity of 0.98 fb−1. The observed event yields are in good overall agreement with the Standard Mo...

The production of D ±- and D 0-mesons has been measured with the ZEUS detector at HERA using an integrated luminosity of 133.6 pb−1. The measurements cover the kinematic range 5

Subjet distributions were measured in neutral current deep inelastic ep scattering with the ZEUS detector at HERA using an integrated luminosity of 81.7pb−1. Jets were identified using the k T cluster algorithm in the laboratory frame. Subjets were defined as jet-like substructures identified by a reapplication of the cluster algorithm at a smalle...

Isolated photon production in deep inelastic ep scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 320 pb(-1). Measurements were made in the isolated-photon transverse-energy and pseudorapidity ranges 4 < E(T)(gamma) < 15 GeV and 0.7 < eta(gamma) < 0.9 for exchanged photon virtualities, Q(2), in the range...

A search for events containing two or more high-transverse-momentum isolated leptons has been performed in ep collisions with the ZEUS detector at HERA using the full collected data sample, corresponding to an integrated luminosity of 480 pb−1. The number of observed events has been compared with the prediction from the Standard Model, searching fo...

Measurements of the neutral current cross sections for deep inelastic scattering in e − p collisions at HERA with a longitudinally polarised electron beam are presented. The single-differential cross-sections d σ/dQ 2, d σ/dx and d σ/dy and the double-differential cross sections in Q 2 and x are measured in the kinematic region y<0.9 and Q 2>185 Ge...

The dissociation of virtual photons, γ*p→Xp, in events with a large rapidity gap between X and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA. The data cover photon virtualities Q²>2 GeV² and γ*p centre-of-mass energies 40<W<240 GeV, with MX>2 GeV, where M...

The dissociation of virtual photons, , in events with a large rapidity gap between X and the outgoing proton, as well as in events in which the leading proton was directly measured, has been studied with the ZEUS detector at HERA. The data cover photon virtualities and centre-of-mass energies , with , where is the mass of the hadronic final state,...

Events with at least two high transverse momentum leptons (electrons or muons) are studied using the H1 and ZEUS detectors at HERA with an integrated luminosity of 0.94 fb^{-1}. The observed numbers of events are in general agreement with the Standard Model predictions. Seven di- and tri-lepton events are observed in e^+p collision data with a scal...

A search for events containing two or more high-transverse-momentum isolated leptons has been performed in ep collisions with the ZEUS detector at HERA using the full collected data sample, corresponding to an integrated luminosity of 480 pb−1. The number of observed events has been compared with the prediction from the Standard Model, searching fo...

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...

Internal report | Preprint

Journal article

A search for events with an isolated high-energy lepton and large missing transverse momentum has been performed with the ZEUS detector at HERA using a total integrated luminosity of 504 pb−1. The results agree well with Standard Model predictions. The cross section for production of single W bosons in electron–proton collisions with unpolarised el...

Beauty production in events containing two muons in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb(-1). A low transverse-momentum threshold for muon identification, in combination with the large rapidity coverage of the ZEUS muon system, gives access to almost the full phase space for beaut...

Journal article

The J/ψ decay angular distributions have been measured in inelastic photopro-duction in ep 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 ang...

A search for events containing an isolated electron or muon and missing transverse momentum produced in $e^{\pm}p$ collisions is performed with the H1 and ZEUS detectors at HERA. The data were taken in the period 1994--2007 and correspond to an integrated luminosity of 0.98 fb$^{-1}$. The observed event yields are in good overall agreement with the...