The H 1 liquid argon calorimeter system

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A search for single top quark production is performed in the full e ± p data sample collected by the H1 experiment at HERA, corresponding to an integrated luminosity of 474 pb −1 . Decays of top quarks into a b quark and a W boson with subsequent leptonic or hadronic decay of the W are investigated. A multivariate analysis is performed to discriminate top quark production from Standard Model background processes. An upper limit on the top quark production cross section via flavour changing neutral current processes σ(ep → etX) < 0.25 pb is established at 95% CL. Limits on the anomalous coupling κ tuγ are derived.Accepted by Phys. Lett. B

Section: Experimental Conditionsmentioning

confidence: 99%

Search for single top quark production at HERA

Aaron¹,

Martin²,

Alexa³

et al. 2009

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“…Jets, photons and electrons are measured with the Liquid Argon (LAr) calorimeter [17], which covers the polar angle range 4 • < θ < 154 • with full azimuthal acceptance. Electromagnetic shower energies are measured with a precision of σ(E)/E = 12%/ E/GeV ⊕ 1% and hadronic energies with σ(E)/E = 50%/ E/GeV ⊕ 2%, as measured in test beams.…”

Section: The H1 Detectormentioning

confidence: 99%

A general search for new phenomena in ep scattering at HERA

Aktas

Andreev²,

Anthonis

et al. 2004

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A model-independent search for deviations from the Standard Model prediction is performed in e + p and e − p collisions at HERA using H1 data corresponding to an integrated luminosity of 117 pb −1 . For the first time all event topologies involving isolated electrons, photons, muons, neutrinos and jets with high transverse momenta are investigated in a single analysis. Events are assigned to exclusive classes according to their final state. A statistical algorithm is developed to search for deviations from the Standard Model in the distributions of the scalar sum of transverse momenta or invariant mass of final state particles and to quantify their significance. A good agreement with the Standard Model prediction is observed in most of the event classes. The most significant deviation is found for a topology containing an isolated muon, missing transverse momentum and a jet, consistent with a previously reported observation.To be submitted to Phys. Lett. B A. Aktas 10 , V. Andreev 26

“…Forward of the CT is the Forward Tracker (FT) covering the polar angular range 7 • to 25 • . Surrounding the trackers is a highly segmented liquid argon (LAr) sampling calorimeter [10] consisting of an inner electromagnetic section and an outer hadronic section. Polar angle coverage is from 4 • to 153 • .…”

Section: Experimental Conditionsmentioning

confidence: 99%

Photo-production of ψ(2S) mesons at HERA

Adloff¹,

Aïd²,

Anderson³

et al. 1998

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Quasi-elastic (z > 0.95) photo-production of ψ(2S) mesons has been observed at HERA for photon-proton centre-of-mass energies in the range 40 to 160 GeV. The ψ(2S) mesons were identified through their decays to ℓ + ℓ − and to J/ψ π + π − , where the J/ψ subsequently decays to ℓ + ℓ − , the lepton ℓ being either a muon or an electron. The cross-section for quasi-elastic photoproduction was measured to be (18.0 ± 2.8(stat) ± 3.0(syst)) nb at a photon-proton centre-of-mass energy of 80 GeV. The ratio of the ψ(2S) to J/ψ quasi-elastic cross-sections is (0.150 ± 0.027(stat) ± 0.022(syst)).