Showing papers by "Hermann Kolanoski published in 1996"
TL;DR: In this paper, a new measurement of the proton structure function F 2 ( x, Q 2 ) is reported for momentum transfers squared Q 2 between ].5 GeV 2 and 5000 GeV2 and for Bjorken x between 3 · 10 −5 and 0.32 using data collected by the HERA experiment H1 in 1994.
192 citations
TL;DR: In this article, the authors presented results on J/ψ mesons in ep interactions in the H1 experiment at HERA and showed that the cross-section of diffractive Jψ production with proton dissociation is of similar magnitude as the elastic cross-sectional area.
93 citations
Particle Physics and Astronomy Research Council1, Rutherford Appleton Laboratory2, Technical University of Dortmund3, DSM4, Heidelberg University5, University of Kiel6, Slovak Academy of Sciences7, Queen Mary University of London8, Lund University9, Intas Biopharmaceuticals10, École Polytechnique11, Centre national de la recherche scientifique12, Academy of Sciences of the Czech Republic13, Charles University in Prague14
21 May 1996-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, the properties of a high resolution lead/scintillating-fibre calorimeter to upgrade the backward region of the H1 detector were studied with electrons in the energy range from 2-60 GeV.
Abstract: The properties of final modules of a high resolution lead/scintillating-fibre calorimeter to upgrade the backward region of the H1 detector were studied with electrons in the energy range from 2–60 GeV. The electromagnetic calorimeter consists of scintillating fibres with a diameter of 0.5 mm embedded in a lead matrix. This small fibre radius, in combination with a lead-to-fibre ratio of 2.27:1, ensures excellent energy resolution which has been measured to be δ/E=7.1%/ E/GeV ⊕ 1.0% . The spatial resolution as a function of energy for impact points at the center of a cell is given by 4.4 mm/ E/GeV + 1.0 mm . The time resolution was found to be better than 0.4 ns.
74 citations
TL;DR: In this paper, the total cross sections for elastic electroproduction of P and Jψ mesons for Q2 > 8 GeV2 and W ≥ 90 GeV/c2 were measured at HERA with the H1 detector with an integrated electron-proton luminosity of ⋍3 pb−1.
63 citations
TL;DR: The lower energy point was measured by observing directly the ϱ0 decay giving a cross section of 9.1 ± 0.9 (stat.) ± 2.5 (syst.) μb.
53 citations
TL;DR: In this article, the D∗± meson photoproduction cross section has been measured with the H1 detector in two different, but partly overlapping, kinematical regions.
46 citations
TL;DR: In this paper, the properties of the hadronic final state in photoproduction events with large transverse energy were studied at the electron-proton collider HERA.
Abstract: Properties of the hadronic final state in photoproduction events with large transverse energy are studied at the electron-proton collider HERA. Distributions of the transverse energy, jets and underlying event energy are compared to
% MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWexLMBb50ujb% qeguuDJXwAKbacfiGaf8hCaaNbaebacqWFWbaCaaa!3DB7!
$$\bar pp$$
data and QCD calculations. The comparisons show that theγp events can be consistently described by QCD models including — in addition to the primary hard scattering process — interactions between the two beam remnants. The differential jet cross sectionsdσ/dE
T
jet
anddσ/dη
jet are measured.
42 citations
TL;DR: In this paper, a search for leptoquarks at HERA was performed in H1 using 1994 e+ p data corresponding to an integrated luminosity of about 3 pb−1.
32 citations
TL;DR: In this paper, the evolution withW andQ2 of the multiplicity distribution and of multiplicity moments in pseudorapidity domains of varying size is studied in the current fragmentation region of the hadronic centre-of-mass frame.
Abstract: Using the H1 detector at HERA, charged particle multiplicity distributions in deep inelastice+p scattering have been measured over a large kinematical region. The evolution withW andQ2 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 Binomial and Lognormal distributions are presented.
29 citations
TL;DR: In this paper, the Q 2 dependence and the total cross sections for charged and neutral current processes are measured in e ± p reactions for transverse momenta of the outgoing lepton larger than 25 GeV.
28 citations
TL;DR: In this paper, the first results on D0 and D* production in deep inelastic $ep$ scattering are reported using data collected by the H1 experiment at HERA in 1994.
Abstract: First results on inclusive D0 and D* production in deep inelastic $ep$ scattering are reported using data collected by the H1 experiment at HERA in 1994. Differential cross sections are presented for both channels and are found to agree well with QCD predictions based on the boson gluon fusion process. A charm production cross section for 10~GeV$^2\le Q^2\le100$~GeV$^2$ and $0.01\le y\le0.7$ of $\sigma\left(ep\rightarrow c\overlinecX\right) = (17.4 \pm 1.6 \pm 1.7 \pm 1.4)$~nb is derived. A first measurement of the charm contribution F2_charm(x,Q^2) to the proton structure function for Bjorken $x$ between $8\cdot10^{-4}$ and $8\cdot10^{-3}$ is presented. In this kinematic range a ratio F2_charm/F2= 0.237\pm0.021{+0.043\atop-0.039}$ is observed.
16 Jul 1996
TL;DR: Neural net algorithms like the Hopfield model have been applied for pattern recognition in tracking detectors and self-organizing networks for the recognition of features in large data samples are discussed.
Abstract: The application of Artificial Neural Networks in Particle Physics is reviewed. Most common is the use of multi-layer perceptrons for event classification and function approximation. This network type is best suited for a hardware implementation and special VLSI chips are available which are used in fast trigger processors. Also discussed are self-organizing networks for the recognition of features in large data samples. Neural net algorithms like the Hopfield model have been applied for pattern recognition in tracking detectors.
[...]
TL;DR: The ARGUS experiment as discussed by the authors has contributed significantly to our understanding of beauty and charmed hadrons, τ Leptons, mesons, ϒϒ interactions and fragmentation processes.
Journal Article•
01 Jan 1996-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
Centre national de la recherche scientifique1, Slovak Academy of Sciences2, Rutherford Appleton Laboratory3, DSM4, Academy of Sciences of the Czech Republic5, University of Kiel6, Technical University of Dortmund7, Queen Mary University of London8, Lebedev Physical Institute9, Heidelberg University10, Lund University11, École Polytechnique12, University of Birmingham13, Charles University in Prague14
21 Nov 1996-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, the energy response to minimum ionizing particles and interacting pions was investigated in the 1 to 7 GeV energy range using data taken at the CERN Proton Synchrotron.
Abstract: Hadronic response and electron identification performance of the new H1 lead-scintillating fibre calorimeter are investigated in the 1 to 7 GeV energy range using data taken at the CERN Proton Synchrotron. The energy response to minimum ionizing particles and interacting pions are studied and compared to Monte Carlo simulations. The measured energy of pions interacting either in the electromagnetic or in the hadronic section is found to scale linearly with the incident energy, providing an energy resolution σ E ∼ 38% within a depth of one interaction length and σ E ∼ 29% for a total depth of two interaction lengths. Several electron identification estimators are studied and combined as a function of energy and impact point. The probability for pions to be misidentified as electrons of any measured energy above 1 GeV ranges from 5% (for 2 GeV incident pions) to 0.4% (at 7 GeV) for an electron detection efficiency of 90%. The probability for pions of a given energy to be misidentified as electrons of the same energy falls to 0.25% at 7 GeV.
TL;DR: In this paper, a search for R-parity violating supersymmetry is performed in collisions at HERA using H1 1994e + data, and the existence of first generation squarks is excluded for masses up to 240 GeV for coupling values λ′≳√4πα� em.
Abstract: A search for squarks ofR-parity violating supersymmetry is performed inep collisions at HERA using H1 1994e
+ data. Direct single production of squarks of each generation bye
+-quark fusion via a Yukawa coupling λ′ is considered. All possibleR-parity violating decays and gauge decays of the squarks are taken into account. No significant deviation from the Standard Model predictions is found in the various multi-lepton and multi-jet final states studied and exclusion limits are derived. At 95% confidence level, the existence of first generation squarks is excluded for masses up to 240 GeV for coupling values λ′≳√4πα
em. The limits obtained are shown to be only weakly dependent on the free parameters of the Minimal Supersymmetric Standard Model. Stop squarks are excluded for masses up to 138 GeV for coupling λ′×cosθ
t toe
+d pairs ≳0.1×√4πα
em, whereθ
t is the mass mixing angle. Light stop squarks are furthermore searched for through pair production inγ-gluon fusion processes. No signal is observed and exclusion limits are derived. Masses in the range 9 to 24.4 GeV are excluded at 95% confidence level for λ′×cosθ
t>10−4.
TL;DR: In this article, a search for selectrons and squarks within the framework of the minimal supersymmetric model is performed and new bounds on the existence of these particles are derived.
TL;DR: Using the ARGUS detector at the e + e − storage ring DORIS II, this paper measured the semileptonic branching ratios of the D 0 meson to be Br (D 0 → e + ν e X ) = (69 ± 03 ± 05) % and Br ( D 0 → μ + ǫ X ) was (60 ± 07 ± 12) %.
TL;DR: Using the ARGUS detector at the e+e− storage ring DORIS II at DESY, this article made two measurements of the mixing parameter χd using kaons as flavour tags.
Journal Article•
TL;DR: In this paper, the transverse energy flow in the hadronic final state was evaluated using a set of estimators which quantify topological properties using available Monte Carlo QCD calculations, and it was demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD.
Abstract: An investigation of the hadronic final state in diffractive and non-diffractive deep-inelastic electron-proton scattering at HERA is presented, where diffractive data are selected experimentally by demanding a large gap in pseudo-rapidity around the proton remnant direction. The transverse energy flow in the hadronic final state is evaluated using a set of estimators which quantify topological properties. Using available Monte Carlo QCD calculations, it is demonstrated that the final state in diffractive DIS exhibits the features expected if the interaction is interpreted as the scattering of an electron off a current quark with associated effects of perturbative QCD. A model in which deep-inelastic diffraction is taken to be the exchange of a pomeron with partonic structure is found to reproduce the measurements well. Models for deep-inelastic ep scattering, in which a sizeable diffractive contribution is present because of non-perturbative effects in the production of the hadronic final state, reproduce the general tendencies of the data but in all give a worse description. © Springer-Verlag 1996.
TL;DR: A maximum likelihood analysis of ARGUS data on two-photon production of π+π+π 0π0π−π− is presented in this paper, where a small fraction of events are due to the production of omega pairs.
01 May 1996-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region, which is able to reject tracks originating in the wall of the narrow beampipe of 10.5 mm radius.
Abstract: A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS micro vertex drift chamber to 245 760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5 mm radius.
01 Jan 1996
TL;DR: In this article, a search for squarks of R-parity violating supersymmetry is performed in collisions at HERA using H1 1994e+ data, and the existence of first generation squarks is excluded for masses up to 240 GeV for coupling values ≥ 4παem.
Abstract: A search for squarks ofR-parity violating supersymmetry is performed inep collisions at HERA using H1 1994e+ data. Direct single production of squarks of each generation bye+-quark fusion via a Yukawa coupling λ′ is considered. All possibleR-parity violating decays and gauge decays of the squarks are taken into account. No significant deviation from the Standard Model predictions is found in the various multi-lepton and multi-jet final states studied and exclusion limits are derived. At 95% confidence level, the existence of first generation squarks is excluded for masses up to 240 GeV for coupling values λ′≳√4παem. The limits obtained are shown to be only weakly dependent on the free parameters of the Minimal Supersymmetric Standard Model. Stop squarks are excluded for masses up to 138 GeV for coupling λ′×cosθt toe+d pairs ≳0.1×√4παem, whereθt is the mass mixing angle.Light stop squarks are furthermore searched for through pair production inγ-gluon fusion processes. No signal is observed and exclusion limits are derived. Masses in the range 9 to 24.4 GeV are excluded at 95% confidence level for λ′×cosθt>10−4.