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28 papers found.
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Prompt neutrino fluxes in the atmosphere with PROSA parton distribution functions

collaboration , M.G. Aartsen et al., Observation and Characterization of a Cosmic [21] C. Lourenco and H.K. Wohri, Heavy avour hadro-production from xed-target to collider [22] O. Behnke , A. Geiser and M

Impact of the heavy-quark matching scales in PDF fits

We investigate the impact of displaced heavy-quark matching scales in a global fit. The heavy-quark matching scale \(\mu _{m}\) determines at which energy scale \(\mu \) the QCD theory transitions from \(N_{F}\) to \(N_{F}+1\) in the variable flavor number scheme (VFNS) for the evolution of the parton distribution functions (PDFs) and strong coupling \(\alpha _S(\mu )\). We study...

Impact of heavy-flavour production cross sections measured by the LHCb experiment on parton distribution functions at low x

The impact of recent measurements of heavy-flavour production in deep inelastic ep scattering and in pp collisions on parton distribution functions is studied in a QCD analysis in the fixed-flavour number scheme at next-to-leading order. Differential cross sections of charm- and beauty-hadron production measured by LHCb are used together with inclusive and heavy-flavour...

Further studies of isolated photon production with a jet in deep inelastic scattering at HERA

AbstractIsolated photons with high transverse energy have been studied in deep inelastic ep scattering with the ZEUS detector at HERA, using an integrated luminosity of 326 pb−1 in the range of exchanged-photon virtuality 10-350 GeV2. Outgoing isolated photons with transverse energy 4 < E T γ  < 15 GeV and pseudorapidity − 0.7 < η γ  < 0.9 were measured with accompanying jets...

Combination and QCD analysis of charm and beauty production cross-section measurements in deep inelastic ep scattering at HERA

. Egli E. Elsen L. Favart 2 A. Fedotov J. Feltesse M. Fleischer A. Fomenko B. Foster 6 E. Gallo A. Garfagnini J. Gayler A. Geiser A. Gizhko L. K. Gladilin L. Goerlich N. Gogitidze Yu. A. Golubkov M ... : 1405 . 6915 24. O. Behnke , A. Geiser , M. Lisovyi , Prog. Nucl. Part. Phys. 84 , 1 ( 2015 ) 25. E. Laenen et al., Phys. Lett. B 291 , 325 ( 1992 ) 26. E. Laenen et al., Nucl. Phys. B 392 , 162 ( 1993

Production of exclusive dijets in diffractive deep inelastic scattering at HERA

12 29 E. Gallo 5 11 12 A. Garfagnini 11 12 15 A. Geiser 11 12 22 A. Gizhko 11 12 22 L. K. Gladilin 10 11 12 Yu. A. Golubkov 10 11 12 J. Grebenyuk 11 12 22 I. Gregor 11 12 22 G. Grzelak 11 12 26 O

Measurement of D ∗ photoproduction at three different centre-of-mass energies at HERA

The photoproduction of D ∗± 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 pseudo-rapidity, η D∗, in the ranges 1.9 < p T D ∗ < 20 GeV and |η D∗| < 1.6. The events were required to have a...

A study of quasi-elastic muon neutrino and antineutrino scattering in the NOMAD experiment

. Dumarchez 6 M. Ellis 10 G.J. Feldman 15 R. Ferrari 3 D. Ferrre 23 V. Flaminio 4 M. Fraternali 3 J.-M. Gaillard 18 E. Gangler 6 23 A. Geiser 20 23 D. Geppert 20 D. Gibin 5 S. Gninenko 8 23 A. Godley 0 J.-J

Measurement of D ± production in deep inelastic ep scattering with the ZEUS detector at HERA

Abstract 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 were measured in the kinematic region 5...

Scaled momentum distributions for \( K_S^0 \) KS and \( \Lambda /\bar{\Lambda } \) in DIS at HERA

Abstract 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  < 40000 GeV2 and 0.001 < x...

Measurement of heavy-quark jet photoproduction at HERA

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 of these vertices. Differential cross...

Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA

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 combination method accounts for the...

Study of taupair production at HERA

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 with the prediction from the...

Inclusive dijet cross sections in neutral current deep inelastic scattering at HERA

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 374 pb−1. The measurement was performed at large values of the photon virtuality, Q 2, between 125 and 20 000 GeV2. The jets were reconstructed with the k T  cluster algorithm in the Breit...

Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA

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 \(\sqrt{s}=318~\mathrm{GeV}\) where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into...

Measurement of beauty production in DIS and extraction at ZEUS

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 114 pb−1. The fraction of events with beauty quarks in the data was determined using the distribution of the transverse momentum of the muon relative to the jet. The cross section...

Measurement of J/ψ photoproduction at large momentum transfer at HERA

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 compared to perturbative QCD calculations.

Diffractive photoproduction of dijets in ep collisions at HERA

Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb-1. The measurements were made in the kinematic range Q2 < 1 GeV2, 0.20<y<0.85 and xIP<0.025, where Q2 is the photon virtuality, y is the inelasticity and xIP is the fraction of the proton momentum taken by the diffractive exchange. The two...

Measurement of D ± and D 0 production in deep inelastic scattering using a lifetime tag at HERA

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<Q 2<1000 GeV2, 0.02<y<0.7, 1.5<p T D <15 GeV and |η D |<1.6. Combinatorial background to the D-meson signals is reduced by using the ZEUS microvertex detector to reconstruct displaced secondary vertices...