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M. Adamus

Publications and source records attributed to M. Adamus.

27 records · Page 2Linked to original sources
arXiv2012

Search for single-top production in ep collisions at HERA

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 current transitions. The result was combined with a previous ZEUS result yielding a total luminosity of 0.50fb-1. A 95% credibility level upper limit of 0.13 pb was obtained for the cross section at the centre-of-mass energy of $\sqrt{s}=315\gev$.

hep-ex↗
arXiv2011

Exclusive electroproduction of two pions at HERA

The exclusive electroproduction of two pions in the mass range 0.4 < Mππ < 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 centre-of-mass energy and t is the squared four-momentum transfer at the proton vertex. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, |F(Mππ)|, assuming that the studied mass range includes the contributions of the ρ, ρ' and ρ" vector-meson states. The masses and widths of the resonances were obtained and the Q2 dependence of the cross-section ratios σ(ρ' \rightarrow ππ)/σ(ρ) and σ(ρ" \rightarrow ππ)/σ(ρ) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e+e- \rightarrow π+π-.

hep-ex↗
arXiv2011

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 sections as a function of jet transverse momentum, $p_{T}^{\text{jet}}$, and pseudorapidity, $η^{\text{jet}}$, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions.

hep-ex↗
arXiv2011

Measurement of beauty production in deep inelastic scattering at HERA using decays into electrons

The production of beauty quarks in ep interactions has been studied with the ZEUS detector at HERA for exchanged four-momentum squared Q^2 > 10 GeV^2, 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 < p_T^e < 8 GeV and pseudorapidity |eta^e| < 1.5. Cross sections for beauty production 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 section as a function of Bjorken-x and Q^2.

hep-ex↗
arXiv2010

Measurement of beauty production in DIS and F_2^bbbar 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 for beauty production was measured in the kinematic range of photon virtuality, Q^2 > 2 Gev^2, and inelasticity, 0.05 < y < 0.7, with the requirement of a muon and a jet. Total and differential cross sections are presented and compared to QCD predictions. The beauty contribution to the structure function F_2 was extracted and is compared to theoretical predictions.

hep-ex↗
arXiv2009

Study of cluster shapes in the Mimosa-5 pixel detector

Beamstrahlung will constitute an important source of background in a pixel vertex detector at the future International Linear Collider. Electron and positron tracks of this origin impact the pixel planes at angles generally larger than those of secondary hadrons and the corresponding clusters are elongated. We report studies of cluster characteristics using test beam electron tracks incident at various angles at a Mimosa-5 pixel matrix.

physics.ins-det↗
arXiv2009

Realistic Simulation of the MAPS Response

The MAPS technology is considered as a possible choice for the ILC Vertex Detector. Test results of MIMOSA-5 sensors indicate that the pixel multiplicity and the single point resolution depend significantly on the incident particle angle. We propose a simple model describing charge distribution in the detector, which can be used for detailed simulation of the Vertex Detector response. Good agreement with beam test data is obtained. A new class for Track Detailed Simulation (TDS) has been developed and implemented in the EUTelescope software framework.

physics.ins-det↗