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165 results on '"W. Beusch"'

1. Enhancement of hyperon production at central rapidity in 158AGeV/cPb–Pb collisions

Author

NA57 Collaboration, F Antinori, P Bacon, A Badalà, R Barbera, A Belogianni, W Beusch, I J Bloodworth, M Bombara, G E Bruno, S A Bull, R Caliandro, M Campbell, W Carena, N Carrer, R F Clarke, A Dainese, D Di Bari, S Di Liberto, R Divià, D Elia, D Evans, G A Feofilov, R A Fini, P Ganoti, B Ghidini, G Grella, H Helstrup, K F Hetland, A K Holme, D Huss, A Jacholkowski, G T Jones, P Jovanovic, A Jusko, R Kamermans, J B Kinson, K Knudson, V Kondratiev, I Králik, A Kravčáková, P Kuijer, V Lenti, R Lietava, R A Loconsole, G Løvhøiden, V Manzari, M A Mazzoni, F Meddi, M E Michalon-Mentzer, A Michalon, M Morando, P I Norman, A Palmeri, G S Pappalardo, B Pastirčák, R J Platt, E Quercigh, F Riggi, D Röhrich, G Romano, K Šafařík, L Šándor, E Schillings, G Segato, M Sené, R Sené, W Snoeys, F Soramel, M Spyropoulou-Stassinaki, P Staroba, M Thompson, R Turrisi, T S Tveter, J Urbán, P van de Ven, P Vande Vyvre, A Vascotto, T Vik, O Villalobos Baillie, L Vinogradov, T Virgili, M F Votruba, J Vrláková, P Závada, Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and NA57

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Nuclear Theory, Hyperon, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Strangeness, Lambda, 01 natural sciences, Omega, Nuclear physics, 0103 physical sciences, Transverse momentum, Rapidity, Nuclear Experiment (nucl-ex), Nuclear Experiment, 010306 general physics, Nucleon, Nuclear Physics
Abstract

Results are presented on hyperon and antihyperon production in Pb-Pb, pPb and pBe collisions at 158 GeV/c per nucleon. Lambda, Xi and Omega yields have been measured at central rapidity and medium transverse momentum as functions of the centrality of the collision. Comparing the yields in Pb-Pb to those in pBe interactions, strangeness enhancement is observed. The enhancement increases with the centrality and with the strangeness content of the hyperons, reaching a factor of about 20 for the Omega in the central Pb-Pb collisions., submitted to J. Phys. G.: Nucl. Part. Phys

Published
2006
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2. A measurement of $\lambda$ polarization in inclusive production by $\Sigma^{-}$ of 340 GeV/c in C and Cu targets

Author

L. Rossi, M. Rey-Campagnolle, U. Dersch, E. Vesin, K. Martens, K. Vorwalter, S. G. Gerassimov, M. I. Adamovich, M. Buenerd, H. Rudolph, T. Haller, Bogdan Povh, W. Bruckner, E. Wittmann, P. Martin, W. Beusch, T. Walcher, J. Pochodzalla, M. Beck, P. Grafstrom, E. Hubbard, D. Barberis, R. Werding, S. Masciocchi, R. Michaels, G. Rosner, S. Brons, Mikhail Zavertyaev, O. Thilmann, Z. Ren, G. Walder, Jürgen Engelfried, K. Konigsmann, J. Chauvin, A. Simon, M. Boss, F. Charignon, D. Newbold, C. Newsom, C. Busch, N. Keller, V. Smith, Y. A. Alexandrov, A. Fournier, C. Scheel, R. Ransome, L. Schmitt, U. Muller, I. Konorov, H. W. Siebert, S. Paul, F. Dropmann, S. P. Baranov, M. Heidrich, R. B. Hurst, C. Berat, E. A. Chudakovc, I. K. Potashnikova, A. Trombini, B. Volkemer, F. Faller, C. Buscher, M. Godbersen, H. Neeb, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), WA89, and Publica

Subjects
Physics, Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Hyperon, Sigma, Atomic physics, 010306 general physics, Polarization (waves), Lambda, 01 natural sciences, Engineering (miscellaneous)
Abstract

We have measured the polarization of Λ\LambdaΛ hyperons produced inclusively by a Σ−\Sigma^-Σ− beam of 340 GeV/c momentum in nuclear targets. From a sample of 9.5 millions of identified Λ\LambdaΛ decays, polarizations were determined in the range xF>0.1x_F \gt 0.1xF​>0.1 and pt≤1.6p_t\leq 1.6pt​≤1.6 GeV/c . The polarization w.r.t. the production normal is mainly positive for xF≥0.3x_F \geq 0.3xF​≥0.3. At fixed values of xFx_FxF​, it increases with ptp_tpt​ to a maximum between pt=0.5p_t = 0.5pt​=0.5 and pt=1p_t = 1pt​=1 GeV/c , and then decreases to zero or even negative values, in sharp contrast to the plateau above pt=1p_t = 1pt​=1 GeV/c observed in inclusive Λ\LambdaΛ production by protons.

Published
2004
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3. Further analysis of a direct soft photon excess in π−p interactions at 280 GeV/c

Author

Irakli Minashvili, V. Lenti, A. Kirk, N.A. Russakovich, P. Sonderegger, A. Jacholkowski, Vito Manzari, W. Beusch, B. R. French, G. Tchlatchidze, J.B. Kinson, I. Vichou, T. J. Brodbeck, O. Villalobos Baillie, David H. Evans, G. Vassiliadis, V.F. Perepelitsa, R. A. Loconsole, M. Spyropoulou-Stassinaki, P. Ganoti, and A. Belogianni

Subjects
Physics, Particle physics, Nuclear and High Energy Physics, Photon, Soft photon, Meson, Bremsstrahlung, Astrophysics::High Energy Astrophysical Phenomena, Elementary particle, Electromagnetic radiation, Soft photons, Nuclear physics, Massless particle, Pion, π−p interactions, Photon excess, High Energy Physics::Experiment, Nuclear Experiment
Abstract

In this Letter we present additional experimental characteristics of anomalous soft photon radiation observed in π−p interactions at 280 GeV/c in the CERN experiment WA91, together with a re-calculated ratio of the observed direct soft photon signal to the expected level of the hadronic inner bremsstrahlung, which is found to be 5.3±1.0. The other presented characteristics, energy dependence and angular distributions of direct soft photons, show the similarity of the observed signal to the expected hadronic bremsstrahlung behaviour.

Published
2002
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4. A study of $\Sigma^{\pm}$ , $\Sigma^{*\pm}$ and $\overline{\Sigma}^-_{1385}$ production in the hyperon beam experiment WA89 at CERN

Author

C. Berat, D. Barberis, Y. A. Alexandrov, B. Volkemer, J. Pochodzalla, U. Dersch, Mikhail Zavertyaev, C. Newsom, G. Walder, V. Smith, D. Newbold, J. Chauvin, S. P. Baranov, K. Vorwalter, S. G. Gerassimov, M. Heidrich, W. Beusch, U. Muller, P. Grafstrom, M. Godbersen, H. Neeb, I. K. Potashnikova, R. Werding, C. Büscher, N. Keller, O. Thilmann, A. Fournier, G. Rosner, T. Walcher, K. Martens, E. Wittmann, Bogdan Povh, C. Scheel, M. Rey-Campagnolle, L. Rossi, R. Michaels, M. Buenerd, M. I. Adamovich, R. B. Hurst, Z. Ren, A. Simon, S. Masciocchi, E. A. Chudakov, L. Schmitt, C. Busch, R. Ransome, P. Martin, S. Brons, W. Brückner, Jürgen Engelfried, E. Hubbard, S. Paul, F. Faller, H. W. Siebert, F. Dropmann, T. Haller, Marcus Beck, H. Rudolph, M. Boss, F. Charignon, A. Trombini, K. Königsmann, E. Vesin, and I. Konorov

Subjects
Physics, Particle physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, 0211 other engineering and technologies, Hyperon, Sigma, 02 engineering and technology, 01 natural sciences, Nuclear physics, Momentum, 0103 physical sciences, High Energy Physics::Experiment, Neutron, Production (computer science), Nuclear Experiment, Engineering (miscellaneous), Beam (structure), 021101 geological & geomatics engineering
Abstract

We report on a measurement of the inclusive production cross sections for \(\Sigma^{\pm}\), \(\Sigma^{\pm}_{1385}\), \(\Sigma^{\pm}_{1660}\) and \(\overline{\Sigma}^-_{1385}\) in the CERN hyperon beam experiment WA89, using a \(\Sigma^- / \pi^-\) beam of 345 GeV/c momentum and neutrons of 260 GeV/c mean momentum. A strong leading particle effect was observed for all negative \(\Sigma\) and \(\Sigma^*\). The results are compared with predictions from phenomenological models.

Published
2001
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5. Centrality dependence of the expansion dynamics in Pb-Pb collisions at 158AGeVc-1

Author

Ivan Kralik, Jozef Urban, M. Morando, B. Ghidini, R.A. Loconsole, R. Lietava, J.B. Kinson, A.K. Holme, V. Lenti, Haavard Helstrup, G. Romano, I. J. Bloodworth, N. Carrer, M. Henriquez, Giacomo Bruno, W. Beusch, O. Villalobos Baillie, K. Knudson, M. A. Mazzoni, Karel Safarik, A. Jacholkowski, Vito Manzari, Pavel Staroba, Dieter Røhrich, T. Vik, Petr Zavada, M.F. Votruba, F. Fayazzadeh, David H. Evans, G. Grella, Domenico Di Bari, Gunnar Løvhøiden, G.F. Segato, Michael A. Thompson, E. Quercigh, M.E. Michalon-Mentzer, K. Fanebust, R. A. Fini, A. Michalon, Rocco Caliandro, P.I. Norman, G. T. Jones, Davide Elia, L. Šándor, S. Di Liberto, B. Pastirčák, Federico Antinori, Franco Meddi, and Tiziano Virgili

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Nuclear Theory, Hadron, Function (mathematics), Collision, Omega, Nuclear physics, Transverse plane, Coulomb, Nuclear Experiment, Nucleon
Abstract

Two-particle correlation functions of negatively charged hadrons from Pb-Pb collisions at 158?GeV?c-1/nucleon have been measured by the WA97 experiment at the CERN SPS. A Coulomb correction procedure that assumes an expanding source has been implemented. Within the framework of an expanding thermalized source model the size and dynamical state of the collision fireball at freeze-out have been reconstructed as a function of the centrality of the collision. Less central collisions exhibit a different dynamics than central ones: both transverse and longitudinal expansion velocities are slower, the expansion duration is shorter and the system freezes out, showing smaller dimensions and higher temperature.

Published
2001
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6. Strange baryon production in Pb-Pb collisions at 158AGeV/c

Author

R.A. Loconsole, G. Romano, K. Šafařík, Michael A. Thompson, M. Henriquez, K. Fanebust, Petr Zavada, Davide Elia, Vito Manzari, K. Knudson, W. Beusch, M.F. Votruba, D. Huss, Pavel Staroba, G.F. Segato, F. Fayazzadeh, M. Morando, M. A. Mazzoni, L. Šándor, V. Lenti, Rocco Caliandro, B. Ghidini, I. J. Bloodworth, J. Ftáčnik, Ivan Kralik, Haavard Helstrup, E. Quercigh, David H. Evans, A.K. Holme, T. Vik, Domenico Di Bari, Dieter Røhrich, P.I. Norman, G. T. Jones, O. Villalobos Baillie, J.B. Kinson, M.E. Michalon-Mentzer, N Carrer, Gunnar Løvhøiden, S. Di Liberto, G. Grella, R. A. Fini, A. Michalon, B. Pastirčák, Franco Meddi, R. Lietava, Marisa Gulino, Tiziano Virgili, Federico Antinori, Giorgio Torrieri, Jozef Urban, and A. Jacholkowski

Subjects
Baryon, Physics, Nuclear physics, Nuclear and High Energy Physics, chemistry, Nuclear Theory, Production (economics), chemistry.chemical_element, Beryllium, Nuclear Experiment, Lambda, Omega, Deconfinement
Abstract

The experiment WA97 is dedicated to the study of strange baryon production in Pb-Pb interactions at SPS energy. Results on the production of strange and multistrange baryons at midrapidity in Pb-Pb at 158 A GeV c-1 are reported and compared with those from p-Pb and p-Be reactions at the same energy. The evidence for deconfinement emerging from the observed pattern of strange baryon production is discussed.

Published
2001
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7. Enhancement of strange and multi-strange baryons in central Pb−Pb interactions at 158 GeV/c per nucleon

Author

O. Villalobos Baillie, Giorgio Torrieri, Jozef Urban, Domenico Di Bari, Rocco Caliandro, K. Fanebust, M.F. Votruba, Trine Spedstad Tveter, K. Knudson, Federico Antinori, Ivan Kralik, R.A. Loconsole, N. Carrer, P.I. Norman, G. T. Jones, J. Ftáčnik, M. Morando, L. Šándor, M. A. Mazzoni, Michael A. Thompson, Gunnar Løvhøiden, I. J. Bloodworth, B. Ghidini, Petr Zavada, R. A. Fini, A. Michalon, S. Di Liberto, Franco Meddi, David H. Evans, G.F. Segato, G. Grella, E. Quercigh, B. Pastirčák, A. Jacholkowski, Tiziano Virgili, Davide Elia, M.E. Michalon-Mentzer, R. Lietava, J.B. Kinson, Vito Manzari, H. Bakke, W. Beusch, Pavel Staroba, D. Huss, H. Helstrup, G. Romano, T.F. Thorsteinsen, K. Šafařík, V. Lenti, and A.K. Holme

Subjects
Baryon, Nuclear physics, Physics, Nuclear and High Energy Physics, Strange matter, Particle physics, Strange quark, Hyperon, Nucleon, Omega baryon, Lambda baryon, Xi baryon
Published
2000
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8. Hyperon and negative particle production at central rapidity in proton-Beryllium interactions at 158 GeV/c

Author

Giorgio Torrieri, Jozef Urban, R.A. Loconsole, J. Ftáčnik, O. Villalobos Baillie, Federico Antinori, N. Carrer, W. Beusch, Pavel Staroba, M. Morando, B. Ghidini, Davide Elia, M.F. Votruba, J.B. Kinson, R. A. Fini, V. Lenti, D. Huss, Petr Zavada, Trine Spedstad Tveter, I. J. Bloodworth, G. Romano, Franco Meddi, A.K. Holme, A. Michalon, Vito Manzari, P.I. Norman, G. T. Jones, G. Grella, A. Jacholkowski, M. A. Mazzoni, K. Šafařík, H. Bakke, T.F. Thorsteinsen, L. Šándor, David H. Evans, Ivan Kralik, Michael A. Thompson, B. Pastirčák, Gunnar Løvhøiden, G.F. Segato, E. Quercigh, M.E. Michalon-Mentzer, Haavard Helstrup, T. Virgili, Domenico Di Bari, K. Knudson, S. Di Liberto, R. Lietava, K. Fanebust, and Rocco Caliandro

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Meson, Nuclear Theory, Hadron, Hyperon, Elementary particle, Hyperons, Strangeness, Nuclear physics, Baryon, Rapidity, Quark Gluon Plasma, Nuclear Experiment
Abstract

A study of the strangeness enhancement in Lead-Lead collisions with respect to proton-induced reactions is being carried out at the CERN SPS by the WA97 experiment: up to now, data from proton-Lead collisions have been used as a reference sample. In this paper we report on a study of particle production in proton-Beryllium collisions. These collisions are expected to constitute a better reference sample than p-Pb, because of the lighter target. The analysis of hyperon and negative particle production is presented and the results are compared with those previously obtained from Pb-Pb and p-Pb collisions.

Published
1999
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9. Transverse mass spectra of strange and multiply—strange particles in Pb—Pb collisions at 158 A GeV/c

Author

Franco Meddi, H. Bakke, Tiziano Virgili, Ivan Kralik, M.F. Votruba, Federico Antinori, M. A. Mazzoni, K. Knudson, R.A. Loconsole, Davide Elia, N. Carrer, Michael A. Thompson, V. Lenti, A.K. Holme, G. Grella, L. Šándor, I. J. Bloodworth, M. Morando, Gunnar Løvhøiden, G.F. Segato, E. Quercigh, O. Villalobos Baillie, Trine Spedstad Tveter, Pavel Staroba, B. Ghidini, M.E. Michalon-Mentzer, Haavard Helstrup, K. Šafařík, P.I. Norman, G. T. Jones, J. Urban, S. Di Liberto, R. A. Fini, A. Michalon, B. Pastirčák, R. Lietava, W. Beusch, K. Fanebust, A. Jacholkowski, Vito Manzari, D. Di Bari, D. Huss, Giorgio Torrieri, Rocco Caliandro, J.B. Kinson, David H. Evans, Petr Zavada, J. Ftáčnik, G. Romano, and T.F. Thorsteinsen

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Inverse, Transverse mass, Impact parameter, Nuclear Experiment, Centrality, Omega baryon, Lambda baryon, Omega, Xi baryon
Abstract

The WA97 experiment has measured the transverse mass \(({m_{\mathrm T}})\) spectra for negative hadrons (\(\mathrm{h}^-\)) and strange particles produced at mid–rapidity in Pb–Pb collisions. The increased statistics of analysed data samples allowed us to perform a study of the spectra of \({\rm K_S^0}\), \(\mathrm{\Lambda}\), \(\mathrm{\Xi}\), \(\mathrm{\Omega}\) and \(\mathrm{h}^-\) as a function of the collision centrality. The data, which correspond to the most central 40% of the total inelastic cross section, have been divided into four centrality classes according to the estimated number of nucleons taking part in the collision. The \(m_{\mathrm T}\) spectra, analysed separately for each centrality bin, exhibit only weak (\(\leq\) 15%) centrality dependence. The deviation of the \(\mathrm{\Omega}\) inverse slope from the linear dependence on the particle mass is confirmed even for the most central Pb–Pb collisions.

Published
1999
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10. A partial wave analysis of the centrally produced π0π0 system in pp interactions at 450 GeV/c

Author

T. Hino, Kunio Takamatsu, V.N. Kolosov, Sergey Donskov, Irakli Minashvili, Petr P.M. Shagin, Sergey S.A. Polovnikov, Paolo Martinengo, K. M. Danielsen, G.V. Khaustov, A. Solovjev, Jean Pierre Peigneux, Takemi Nakagawa, A.V. Dolgopolov, M. Venables, B.C. Earl, Yoshiji Yasu, D. Barberis, Susumu Inaba, A. Semenov, V.D. Samoylenko, T. Jacobsen, R. Sené, G. Tchlatchidze, A.M. Blick, V.A. Polyakov, A. A. Kondashov, A. Kirk, Alexandre A.V. Inyakin, M.F. Votruba, W. Klempt, Freddy Binon, A. Sobol, G. T. Jones, S. Maljukov, N. Russakovich, A.V. Singovsky, Andrey Lednev, M. Stassinaki, A. Jacholkowski, Valentine Sugonyaev, K.L. Norman, H. M. Shimizu, J.B. Kinson, T. Ishida, David H. Evans, B. R. French, F.E. Close, W. Beusch, V. Romanovsky, M. Sené, Tsuneaki Tsuru, T. Kinashi, H. Rotscheidt, Jean-Pierre Stroot, O. Villalobos Baillie, V. Rumyantsev, and V. Lenti

Subjects
Physics, Nuclear physics, Momentum, Nuclear and High Energy Physics, Partial wave analysis, Incident beam, Channel (broadcasting), Atomic physics, Central region
Abstract

A partial wave analysis of the centrally produced π 0 π 0 channel has been performed in pp collisions using an incident beam momentum of 450 GeV/c. An unambiguous physical solution has been found. Evidence is found for the f 0 (980), f 0 (1300) and f 0 (1500) in the the S -wave. and the f 2 (1270) is observed dominantly in the D 0 − -wave. In addition, there is evidence for a broad enhancement in the D -wave below 1 GeV.

Published
1999
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11. The Omega RICH in the CERN hyperon beam experiment

Author

G. Wälder, O. Thilmann, H. W. Siebert, S.G. Gerassimov, Jürgen Engelfried, K. Martens, P. Lennert, U. Müller, W. Beusch, H. Rieseberg, V.J. Smith, M. Boss, Dave M Newbold, and W. Klempt

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Spectrometer, Physics::Instrumentation and Detectors, Hyperon, Omega, Particle detector, Nuclear physics, Antiproton, Antimatter, High Energy Physics::Experiment, Nuclear Experiment, Instrumentation, Cherenkov radiation
Abstract

The Omega RICH, a large-aperture detector for identification of secondary pions, kaons, and (anti) protons was in operation at the CERN Omega spectrometer facility between 1984 and 1994. Cherenkov photons from a 5 m long radiator were detected in drift chambers with quartz windows, using TMAE-loaded counting gases. The RICH was used by experiments WA69 and WA82, until 1988. It was then equipped with new drift chambers and mirrors and was in use since 1990 in experiments WA89 and WA94. The setup in the WA89 hyperon beam experiment is described in more detail and efficiencies, resolutions, and physics results are discussed.

Published
1999
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12. Production of hyperons and anti-hyperons in heavy-ion collisions at SPS: Experiments at the CERN Omega spectrometer

Author

G. Romano, A. Volte, Leonardo Paolo Rossi, Håvard Helstrup, R. Lietava, G. Vassiliadis, M. Morando, N. Carrer, P. Middelkamp, Anton Jusko, J.A. Lien, B. Sopko, T. Storås, Gunnar Løvhøiden, K.L. Norman, F. Posa, I. Králik, A. Di Mauro, Petr Zavada, J. Šťastný, M. Luptak, Vito Manzari, Paolo Martinengo, O. Villalobos Baillie, R. A. Ricci, V. Lenti, G.F. Segato, M. Vaníčková, J.B. Kinson, Rocco Caliandro, C. Salvo, Giovanni Darbo, J. Ftacnik, Jean-Charles Fontaine, E. Quercigh, A. Kirk, J. Bohm, G. Grella, E. Chesi, Bianca Osculati, T. Virgili, A. Diaczek, M. Venables, H. Rotscheidt, S. Simone, W. Beusch, C. Voltolini, M.E. Michalon-Mentzer, S. Saladino, J. P. Davies, K. Šafařík, V.A. Kachanov, K. Knudson, A.K. Holme, Alberto Andrighetto, D. Huss, P. Sennels, R. A. Fini, T. Kachelhoffer, A. Michalon, F. Pellegrini, S. Szafran, A. Jacholkowski, M. T. Muciaccia, N. Armenise, Michele Guida, K. Piska, J. C. Lassalle, Gianfranca De Rosa, W. Geist, P. Sené, K. Fanebust, L. Sandor, T.F. Thorsteinsen, D. Elia, J. Bán, P. Jovanovic, E. Nappi, David H. Evans, M. G. Catanesi, I. Mácha, Dario Barberis, A. Singovski, M. Dameri, Franco Meddi, T. Scognetti, Federico Antinori, Erik H.M. Heijne, D. Di Bari, Eugenio Cantatore, M. A. Mazzoni, B. Ghidini, E. Andersen, F. Navach, M. Sené, M. Campbell, G. Tomasicchio, J. Urban, M.F. Votruba, W. Klempt, H. Beker, V. Mack, Pavel Staroba, R. A. Loconsole, S. Di Liberto, B. Pastirčák, Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), WA97, and Heyd, Yvette

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Strange quark, Large Hadron Collider, Spectrometer, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, Hyperon, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Omega, Atomic and Molecular Physics, and Optics, Nuclear physics, Heavy ion, Nuclear Experiment
Abstract

Recent results from the CERN Omega spectrometer on the enhancement of strange and multiply strange particle production in nucleus-nucleus with respect to proton-nucleus collisions are summarized. In particular, the new data from the WA97 experiment on Ω, Ξ and Λ production in PbPb and p-Pb collisions are presented and discussed.

Published
1999
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13. Enhancement of strange and multi-strange baryons and anti-baryons in SW interactions at 200 GeV/c

Author

J. C. Lassalle, M. Sené, V. Lenti, B. Ghidini, J.A. Lien, A. Jacholkowski, J.B. Kinson, K. Šafařík, R. P. Barnes, Federico Antinori, M.F. Votruba, A. Kirk, Davide Elia, R. A. Fini, R.A. Loconsole, A. C. Bayes, K. Knudson, J. P. Davies, A. Volte, Vito Manzari, R. Sené, Håvard Helstrup, B. De La Cruz, G. Vassiliadis, E. Quercigh, O. Villalobos Baillie, Rocco Caliandro, David H. Evans, W. Beusch, Domenico Di Bari, F. Navach, A.K. Holme, and M. Venables

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Particle physics, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Plasma, Baryon, Nuclear physics, High Energy Physics::Experiment, Heavy ion, Nuclear Experiment, Nucleon
Abstract

Strange and multistrange baryon production is expected to be enhanced in heavy ion interactions if a phase transition from hadronic matter to a Quark-Gluon Plasma takes place. The production yields of Λs, Λ s, Ξ−s, and Ξ + s relative to the production of negative particles are presented for sulphur-tungsten interactions at 200 GeV/c per nucleon. These production yields are compared to those produced in proton-tungsten interactions and the enhancements of strange and multistrange baryons and antibaryons are presented.

Published
1999
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14. A study of the centrally produced K(892)(892)and φω systems in pp interactions at 450 GeV/c

Author

D. Barberis, W. Beusch, F.G. Binon, A.M. Blick, F.E. Close, K.M. Danielsen, A.V. Dolgopolov, S.V. Donskov, B.C. Earl, D. Evans, B.R. French, T. Hino, S. Inaba, A.V. Inyakin, T. Ishida, A. Jacholkowski, T. Jacobsen, Jones G.T, G.V. Khaustov, T. Kinashi, J.B. Kinson, A. Kirk, W. Klempt, V. Kolosov, A.A. Kondashov, A.A. Lednev, V. Lenti, S. Maljukov, P. Martinengo, I. Minashvili, T. Nakagawa, K.L. Norman, J.P. Peigneux, S.A. Polovnikov, V.A. Polyakov, V. Romanovsky, H. Rotscheidt, V. Rumyantsev, N. Russakovich, V.D. Samoylenko, A. Semenov, M. Sené, R. Sené, P.M. Shagin, H. Shimizu, A.V. Singovsky, A. Sobol, A. Solovjev, M. Stassinaki, J.P. Stroot, V.P. Sugonyaev, K. Takamatsu, G. Tchlatchidze, T. Tsuru, M. Venables, O. Villalobos Baillie, M.F. Votruba, and Y. Yasu

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Pomeron, Near threshold, Particle physics, Glueball, Mass spectrum, State (functional analysis), Omega
Abstract

A study of the reactions pp -> pfps(K+K-pi+pi-) and pp -> pfps(K+K-pi+pi-pi0) shows evidence for the K*K* and phi omega channels respectively. The K*K* mass spectrum shows a broad distribution with a maximum near threshold and an angular analysis shows that it is compatible with having JP = 2+. The behaviour of the cross-section as a function of centre of mass energy, and the four momentum transfer dependence, are compatible with what would be expected if the K*K* system was produced via double Pomeron exchange. The dPT behaviour of the phi omega channel is similar to what has been observed for all the undisputed qqbar states. In contrast, the dPT behaviour of the K*K* final state is similar to what has been observed for the phi phi final state and for previously observed glueball candidates.

Published
1998
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15. A, Ξ and Ω enhancement at central rapidity in Pb-Pb collisions at 158A GeV/ c

Author

Rocco Caliandro, A. Diaczek, K. Fanebust, J. Urban, B.T.H. Knudsen, A. Singovski, Federico Antinori, Michael A. Thompson, S. Saladino, A.K. Holme, G. Tomasicchio, N. Carrer, Eugenio Cantatore, M. A. Mazzoni, Leonardo Paolo Rossi, B. Ghidini, G. Rosa, Erik H.M. Heijne, G. Vassiliadis, G. Romano, J. C. Lassalle, J.B. Kinson, T.F. Thorsteinsen, D. Di Bari, V. Lenti, Giovanni Darbo, E. Chesi, Bianca Osculati, M. Morando, C. Salvo, M. Dameri, Pavel Staroba, M.F. Votruba, F. Navach, N. Armenise, Anton Jusko, K. Piska, E. Andersen, W. Klempt, Eugenio Nappi, H. Bakke, Michele Guida, F. Posa, Petr Zavada, K. Šafařík, Franco Meddi, D. Elia, A. Jacholkowski, I. Králik, Haavard Helstrup, Paolo Martinengo, T. Scognetti, W. Snoeys, M. Sené, M. Campbell, J. Bán, Dario Barberis, T. Virgili, A. Kirk, B.C. Earl, S. Simone, W. Beusch, A. Volte, R. Lietava, R. Sené, K. Knudson, O. Villalobos Baillie, R. A. Ricci, I. J. Bloodworth, H. Beker, D. Huss, V. Mack, P. Middelkamp, Vito Manzari, David H. Evans, M. G. Catanesi, S. Di Liberto, B. Pastirčák, R. A. Loconsole, J. Ftacnik, Giorgio Torrieri, M. T. Muciaccia, Trine Spedstad Tveter, V.A. Kachanov, P.I. Norman, G. T. Jones, P. Jovanovic, Gunnar Løvhøiden, L. Šándor, F. Pellegrini, R. A. Fini, A. Michalon, J. Bohm, M. Venables, M. Luptak, G.F. Segato, E. Quercigh, M.E. Michalon-Mentzer, Jean-Charles Fontaine, S. Szafran, H. Rotscheidt, T. Kachelhoffer, and G. Grella

Subjects
Nuclear physics, Physics, Particle physics, Nuclear Theory, Quark–gluon plasma, Hyperon, Transverse mass, Rapidity, Strangeness, Nuclear Experiment, Omega, Spectral line
Abstract

A, Ξ and Ω yields and transverse mass spectra have been measured in Pb-Pb and p-Pb collisions at 158A GeV/c. The yields in Pb-Pb interactions are presented as a function of the collision centrality and compared with those obtained from p-Pb collisions. Strangeness enhancement is observed which increases with centrality and with the strangeness content of the hyperon.

Published
1998
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16. Λ, Ξ and Ω production in PbPb collisions at 158 A GeV/c

Author

Michael A. Thompson, S. Saladino, A.K. Holme, Dario Barberis, J. C. Lassalle, Petr Zavada, D. Di Bari, Gunnar Løvhøiden, M. T. Muciaccia, M. Morando, S. Simone, R. A. Fini, L. Šándor, F. Pellegrini, Anton Jusko, G. Grella, K. Knudson, W. Beusch, R. A. Loconsole, N. Carrer, V.A. Kachanov, A. Michalon, S. Szafran, A. Di Mauro, D. Huss, M.E. Michalon-Mentzer, I. Králik, P. Middelkamp, Giovanni Darbo, Paolo Martinengo, M. Luptak, G.F. Segato, F. Posa, E. Quercigh, J. Ftacnik, E. Chesi, Rocco Caliandro, P. Jovanovic, A. Kirk, Trine Spedstad Tveter, G. Romano, A. Singovski, E. Andersen, N. Armenise, W. Snoeys, B. Ghidini, H. Beker, T.F. Thorsteinsen, G. Rosa, H. Rotscheidt, David H. Evans, Jean-Charles Fontaine, P.I. Norman, G. T. Jones, M. Dameri, M. G. Catanesi, Vito Manzari, J. Bohm, V. Mack, J. Bán, Franco Meddi, M. Sené, A. Diaczek, F. Navach, M. Campbell, S. Di Liberto, A. Jacholkowski, M. Venables, T. Kachelhoffer, G. Tomasicchio, Leonardo Paolo Rossi, O. Villalobos Baillie, R. A. Ricci, B. Pastirčák, T. Scognetti, Pavel Staroba, M.F. Votruba, W. Klempt, Eugenio Nappi, Federico Antinori, Erik H.M. Heijne, J. Urban, K. Fanebust, B. Osculati, M.A. Mazzoni, E. Cantatore, J.B. Kinson, A. Volte, R. Lietava, R. Sené, K. Piska, D. Elia, T. Virgili, I.G. Bloodworth, V. Lenti, Michele Guida, C. Salvo, Håvard Helstrup, G. Vassiliadis, and K. Šafařík

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Silicon pixel detectors, Hyperon, Spectral line, Baryon, Nuclear physics, Particle, Transverse mass, Rapidity, Quark Gluon Plasma, Nuclear Experiment
Abstract

Enhanced production of strange baryons and anti-baryons at central rapidity in S-W and S-z.sbnd;S with respect to p-A reactions has been reported by the CERN experiments WA85 and WA94. The WA97 experiment is extending such a study to Pb Pb collisions making use of the newly developed silicon pixel detectors. Results on Λ, Ξ − and Ω − production in Pb Pb collisions at 158 A GeV/ c at central rapidity are presented. Transverse mass spectra and particle ratios are presented. Hyperon yields are given as a function of the collision centrality and compared with those obtained from p-Pb collisions using the same experimental setup.

Published
1998
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17. A study of pseudoscalar states produced centrally in pp interactions at 450 GeV/c

Author

D. Barberis, W. Beusch, F.G. Binon, A.M. Blick, F.E. Close, K.M. Danielsen, A.V. Dolgopolov, S.V. Donskov, B.C. Earl, D. Evans, B.R. French, T. Hino, S. Inaba, A.V. Inyakin, T. Ishida, A. Jacholkowski, T. Jacobsen, G.T. Jones, G.V. Khaustov, T. Kinashi, J.B. Kinson, A. Kirk, W. Klempt, V. Kolosov, A.A. Kondashov, A.A. Lednev, V. Lenti, S. Maljukov, P. Martinengo, I. Minashvili, K. Myklebost, T. Nakagawa, K.L. Norman, J.M. Olsen, J.P. Peigneux, S.A. Polovnikov, V.A. Polyakov, V. Romanovsky, H. Rotscheidt, V. Rumyantsev, N. Russakovich, V.D. Samoylenko, A. Semenov, M. Sené, R. Sené, P.M. Shagin, H. Shimizu, A.V. Singovsky, A. Sobol, A. Solovjev, M. Stassinaki, J.P. Stroot, V.P. Sugonyaev, K. Takamatsu, G. Tchlatchidze, T. Tsuru, M. Venables, O. Villalobos Baillie, M.F. Votruba, and Y. Yasu

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Meson, High Energy Physics::Phenomenology, FOS: Physical sciences, High Energy Physics - Experiment, Pseudoscalar, High Energy Physics - Experiment (hep-ex), Cross section (physics), Pomeron, High Energy Physics::Experiment, Nuclear Experiment, Particle Physics - Experiment
Abstract

A study has been made of pseudoscalar mesons produced centrally in pp interactions. The results show that the eta and etaprime appear to have a similar production mechanism which differs from that of the pi0. The production properties of the eta and etaprime are not consistent with what is expected from double Pomeron exchange. In addition the production mechanism for the eta and etaprime is such that the production cross section are greatest when the azimuthal angle between the pT vectors of the two protons is 90 degrees., 11 pages, Latex, 3 Figures

Published
1998
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18. A study of the centrally produced π+π−π0channel in pp interactions at 450 GeV/c

Author

D. Barberis, W. Beusch, F.G. Binon, A.M. Blick, F.E. Close, K.M. Danielsen, A.V. Dolgopolov, S.V. Donskov, B.C. Earl, D. Evans, B.R. French, T. Hino, S. Inaba, A.V. Inyakin, T. Ishida, A. Jacholkowski, T. Jacobsen, G.V. Khaustov, T. Kinashi, J.B. Kinson, A. Kirk, W. Klempt, V. Kolosov, A.A. Kondashov, A.A. Lednev, V. Lenti, S. Maljukov, P. Martinengo, I. Minashvili, K. Myklebost, T. Nakagawa, K.L. Norman, J.M. Olsen, J.P. Peigneux, S.A. Polovnikov, V.A. Polyakov, Yu.D. Prokoshkin, V. Romanovsky, H. Rotscheidt, V. Rumyantsev, N. Russakovich, V.D. Samoylenko, A. Semenov, M. Sené, R. Sené, P.M. Shagin, H. Shimizu, A.V. Singovsky, A. Sobol, A. Solovjev, M. Stassinaki, J.P. Stroot, V.P. Sugonyaev, K. Takamatsu, G. Tchlatchidze, T. Tsuru, G. Vassiliadis, M. Venables, O. Villalobos Baillie, M.F. Votruba, and Y. Yasu

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Omega, Particle Physics - Experiment, Spin-½
Abstract

The reaction pp -> pf (pi+pi-pi0) ps has been studied at 450 GeV/c in an experiment designed to search for gluonic states. A spin analysis has been performed and the dPT filter applied. The analysis confirms the previous observation that all undisputed qqbar states are suppressed at small dPT. In addition, a clear difference is observed in the production mechanism for the eta and omega. The reaction pp → p f ( π + π − π 0 ) p s has been studied at 450 GeV/c in an experiment designed to search for gluonic states. A spin analysis has been performed and the dP T filter applied. The analysis confirms the previous observation that all undisputed q q states are suppressed at small dP T . In addition, a clear difference is observed in the production mechanism for the η and ω . The reaction pp -> pf (pi+pi-pi0) ps has been studied at 450 GeV/c in an experiment designed to search for gluonic states. A spin analysis has been performed and the dPT filter applied. The analysis confirms the previous observation that all undisputed qqbar states are suppressed at small dPT. In addition, a clear difference is observed in the production mechanism for the eta and omega.

Published
1998
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19. Charged particle production in S-S collisions at 200 GeV/c per nucleon

Author

P. Sennels, K. Šafařík, N. Carrer, T.F. Thorsteinsen, A. Andrighetto, J. C. Lassalle, A. Volte, J. Urban, M. Morando, Federico Antinori, G.F. Segato, R. Sené, O. Villalobos Baillie, Håvard Helstrup, B. Ghidini, K. Knudson, B. De La Cruz, P. Ladron de Guevara, G. Vassiliadis, Ivan Kralik, E. Quercigh, R.A. Loconsole, V. A. Katchanov, Davide Elia, G. Wälder, Petr Zavada, M. Sené, F. Pellegrini, A. Kirk, A.K. Holme, A. Jacholkowski, H.W. Siebert, J. P. Davies, V. Lenti, Jürgen Engelfried, J. Bohm, U. Müller, M. Venables, J. Ftacnik, M.F. Votruba, L. Sandor, F. Navach, R A. Fini, Roman Lietava, Domenico Di Bari, K. Fanebust, David H. Evans, A. C. Bayes, Vito Manzari, W. Beusch, A. Singovski, G. Løvhøiden, K. Martens, K.L. Norman, and J.B. Kinson

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Spectrometer, Physics::Instrumentation and Detectors, Omega, Particle identification, Spectral line, Charged particle, Nuclear physics, Transverse mass, High Energy Physics::Experiment, Rapidity, Nuclear Experiment, Nucleon
Abstract

Charged particle production in central S-S collisions at 200 GeV/c per nucleon has been studied by the WA94 experiment at the CERN-SPS. Particle identification has been provided by the Omega RICH, while a silicon telescope in the Omega spectrometer and an array of MultiWire Proportional Chambers have been used to trace particles through the RICH detector. Production ratios and transverse mass spectra for π±, K± and p( p ) at central rapidity and pT > 1.3 GeV/c are presented.

Published
1997
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20. Confirmation of a soft photon signal in excess of Q.E.D. expectations in π−p interactions at 280 GeV/c

Author

A. Belogianni, W. Beusch, T.J. Brodbeck, D. Evans, B.R. French, A. Jacholkowski, J.B. Kinson, A. Kirk, V. Lenti, R.A. Loconsole, V. Manzari, I. Minashvili, V. Perepelitsa, N. Russakovich, P. Sonderegger, M. Spyropoulou-Stassinaki, G. Tchlatchidze, G. Vassiliadis, I. Vichou, and O. Villalobos-Baillie

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Photon, Soft photon, Spectrometer, Physics::Instrumentation and Detectors, Bremsstrahlung, FOS: Physical sciences, Omega, Signal, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Pi, High Energy Physics::Experiment, Nuclear Experiment, Particle Physics - Experiment
Abstract

Photons produced in pi p interactions at 280 GeV/c were detected by reconstructing the e+e- pairs produced via the materialisation of the photons in a 1 mm thick lead sheet placed in front of the MWPCs of the OMEGA spectrometer at CERN. A soft photon signal 7.8 +/- 1.5 times the Q.E.D. inner bremsstrahlung prediction was observed confirming the results of a previous experiment., 11 pages, Latex, 3 Figures plus layout figure

Published
1997
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21. Hyperon production in proton-sulphur interaction at 200 GeV/c

Author

S. Abatzis, J. Ftáĉnik, V. Lenti, K. Knudson, P. Ladron de Guevara, J. Urban, N. Carrer, M. Venables, J. N. Carney, Domenico Elia, V. A. Katchanov, Federico Antinori, O. Villalobos Baillie, J. L. Narjoux, R. A. Ricci, A. V. Singovsky, A. C. Bayes, M. Morando, E. Andersen, G.F. Segato, L. Sandor, E. Quercigh, K. Šafařík, M. Sené, T.F. Thorsteinsen, A. Volte, Ph. Leruste, J. P. Davies, J. Bohm, R. Lietava, R. Sené, K.L. Norman, D. Di Bari, F. Pellegrini, Petr Zavada, K. Fanebust, Håvard Helstrup, A. Kirk, A. Jacholkowski, B. De La Cruz, W. Beusch, J.B. Kinson, G. Løvhøiden, B. Ghidini, G. Vassiliadis, J. Kahane, M. Benayoun, F. Navach, A.K. Holme, Alberto Andrighetto, M.F. Votruba, David H. Evans, V. Manzari, R. A. Loconsole, R. Fini, J. C. Lassalle, B. R. French, Ivan Kralik, and P. Sennels

Subjects
Physics, Nuclear and High Energy Physics, Strange quark, High Energy Physics::Phenomenology, Hyperon, General Physics and Astronomy, Elementary particle, Lambda baryon, Xi baryon, Nuclear physics, Baryon, Strange matter, Transverse mass, Nuclear Experiment
Abstract

The WA94 collaboration uses the production of strange and anti-strange particles to investigate the properties of hot hadronic matter created in heavy-ion interactions. Λ,\(\bar \Lambda \), Ξ− and\(\bar \Xi ^ + \) particle yields and transverse mass spectra are presented for pS interactions and are compared with those for SS interactions and for the pW and SW interactions of WA85.

Published
1996
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22. LHC1: A semiconductor pixel detector readout chip with internal, tunable delay providing a binary pattern of selected events

Author

F. Pellegrini, Franco Meddi, S. Simone, Giovanni Darbo, Stanislav Pospisil, J. Stastny, E. Chesi, V. Lenti, K. Knudson, F. Lemeilleur, A. Munns, D. Di Bari, K. H. Becks, Eugenio Cantatore, Thierry Gys, H. Beker, Karel Safarik, F. Pengg, A. Jacholkowski, Demetrios Loukas, Federico Antinori, P. Burger, Paolo Martinengo, J.J. Jaeger, F. Krummenacher, L. Lopez, M. Morando, J. C. Lassalle, C. DaVia, Erik H.M. Heijne, G. Humpston, Leonardo Paolo Rossi, W. Klempt, Dario Barberis, P. Middelkamp, B. Lisowski, M. G. Catanesi, M. Letheren, W. Beusch, Kevin M. Smith, C. Sobczynski, M. Campbell, Vaclav Vrba, L. Scharfetter, Jan Jakubek, P. Musico, Rupert Leitner, Pierre Jarron, G. Meddeler, J. Kubasta, Walter Snoeys, M. Luptak, G.F. Segato, Paolo Morettini, E. Quercigh, Saverio D'Auria, S. Di Liberto, J. Ridky, Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and WA97

Subjects
Masking (art), Physics, Nuclear and High Energy Physics, Discriminator, 010308 nuclear & particles physics, business.industry, Amplifier, Detector, Transistor, Integrated circuit, Chip, 01 natural sciences, law.invention, Semiconductor, law, 0103 physical sciences, Optoelectronics, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Detectors and Experimental Techniques, 010306 general physics, business, Instrumentation
Abstract

The Omega3/LHC1 pixel detector readout chip comprises a matrix of 128 × 16 readout cells of 50 μm × 500 μm and peripheral functions with 4 distinct modes of initialization and operation, together more than 800 000 transistors. Each cell contains a complete chain of amplifier, discriminator with adjustable threshold and fast-OR output, a globally adjustable delay with local fine-tuning, coincidence logic and memory. Every cell can be individually addressed for electrical test and masking. First results have been obtained from electrical tests of a chip without detector as well as from source measurements. The electronic noise without detector is ∼ 100 e− rms. The lowest threshold setting is close to 2000 e− and non-uniformity has been measured to be better than 450 e− rms at 5000 e− threshold. A timewalk of

Published
1996
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23. Hyperon production in Pb+Pb collisions at 158 A GeV/c

Author

S. Szafran, Anton Jusko, N. Armenise, Michele Guida, I. Králik, P. Jovanovic, S. Simone, K. Šafařík, Ph. Leruste, H. Helstrup, J. Ftacnik, P. Middelkamp, J. Bán, Paolo Martinengo, E. Nappi, N. Carrer, Leonardo Paolo Rossi, C. Voltolini, Federico Antinori, Håvard Helstrup, Pavel Staroba, Vito Manzari, J.A. Lien, G. Vassiliadis, V. Lenti, K. Fanebust, M. Luptak, G.F. Segato, Eugenio Cantatore, J. Šťastný, K. Knudson, M. Vaníčková, M. A. Mazzoni, S. Di Liberto, L. Lopez, B. Ghidini, A. Singovski, W. Geist, Erik H.M. Heijne, M. Morando, A. Jacholkowski, J.M. Brom, E. Quercigh, R. Blaes, P. Sennels, F. Posa, G. Romano, A. Volte, R. Lietava, R. Sené, B. Pastirčák, A.K. Holme, Alberto Andrighetto, G. Grella, K. Piska, J. L. Narjoux, T.F. Thorsteinsen, E. Andersen, Jean-Charles Fontaine, H. Rotscheidt, F. Navach, M. Dameri, D. Elia, L. Šándor, F. Pellegrini, M. T. Muciaccia, J. P. Davies, O. Villalobos Baillie, R. A. Ricci, David H. Evans, J. C. Lassalle, Petr Zavada, C. Salvo, I. Mácha, Dario Barberis, A. Di Mauro, K.L. Norman, G. Tomasicchio, Giovanni Darbo, V.A. Kachanov, T. Kachelhoffer, E. Chesi, Bianca Osculati, T. Storås, A. Kirk, M. G. Catanesi, B. R. French, M. Sené, B. Sopko, M. Campbell, A. Diaczek, M.E. Michalon-Mentzer, M.F. Votruba, W. Klempt, Franco Meddi, P. Farthouat, J. Bohm, T. Scognetti, J. Urban, H. Beker, J.B. Kinson, M. Venables, Gunnar Løvhøiden, V. Mack, R. A. Fini, A. Michalon, T. Virgili, W. Beusch, D. Huss, M. Benayoun, G. Rosa, and D. Di Bari

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Strange quark, Proton, Hadron, Hyperon, General Physics and Astronomy
Abstract

Preliminary results from WA97 measurements on Λ, Ξ and Ω production in lead-lead and proton-lead collisions are presented, along with a comparison of WA97 proton-lead data with previous WA85 proton-tungsten results. The ratio Ω/Ξ seems to be enhanced in lead initiated reactions compared to proton initiated reactions.

Published
1996
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24. Strangeness production in p+W and S+W Interactions at 200 A GeV/c

Author

David H. Evans, B. R. French, Leonardo Paolo Rossi, T. Storås, R. A. Loconsole, J. C. Lassalle, W. Beusch, Ph. Leruste, M. Benayoun, F. Navach, A. Volte, R. P. Barnes, R. Sené, V. Lenti, J. L. Narjoux, M. Venables, B. Ghidini, K. Knudson, J. N. Carney, V. Manzari, Federico Antinori, R. Fini, A. C. Bayes, E. Quercigh, Håvard Helstrup, B. De La Cruz, G. Vassiliadis, J.A. Lien, A. Jacholkowski, M. Sené, K. Šafařík, S. Abatzis, A. Andrighetto, M.F. Votruba, O. Villalobos-Baillie, J. Kahane, J.B. Kinson, A.K. Holme, D. Evans, D. Di Bari, J. P. Dufey, A. Kirk, D. Elia, and J. P. Davies

Subjects
Nuclear physics, Baryon, Physics, Nuclear and High Energy Physics, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, General Physics and Astronomy, Strangeness production, Transverse mass, Heavy ion, Nuclear Experiment, Spectral line
Abstract

Strange and multistrange baryon and antibaryon production is a useful probe into the dynamics of the hot hadronic matter created in central heavy ion interactions. Relative production yields and transverse mass spectra are presented and compared for pW and SW interactions.

Published
1996
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25. Observation of vertex factorisation breaking in central pp interactions

Author

A.A. Kondashov, Kunio Takamatsu, Hajime Shimizu, S. Maljukov, V.D. Samoylenko, G. Tchlatchidze, David H. Evans, H. Rotscheidt, T. Nakagawa, B.C. Earl, Jean Pierre Peigneux, Yoshiji Yasu, M. Venables, B. R. French, F. Navach, Freddy Binon, V. Manzari, Alexandre A.V. Inyakin, O. Villalobos Baillie, Jean-Pierre Stroot, D. Di Bari, W. Beusch, V. Romanovsky, A. Jacholkowski, J. N. Carney, Sergey Donskov, D. Elia, Masakazu Kobayashi, G. Vassiliadis, G.V. Khaustov, Susumu Inaba, Sergey S.A. Polovnikov, B. Ghidini, Petr P.M. Shagin, A. Solovjev, V.A. Polyakov, R. Sené, Valentine Sugonyaev, A.V. Dolgopolov, D. Barberis, M. Sené, A. V. Shtannikov, Yuri Kulchitsky, A. Kirk, V. A. Lishin, Irakli Minashvili, K.L. Norman, M.F. Votruba, W. Klempt, N.A. Russakovich, J.B. Kinson, Tsuneaki Tsuru, R. A. Loconsole, A. Semenov, V. Lenti, Paolo Martinengo, Yu.D. Prokoshkin, T. Kinashi, R. A. Fini, A.V. Singovsky, and Andrey Lednev

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Factorization, Particle Physics - Experiment, Vertex (geometry)
Abstract

Central \pipi events produced in pp interactions are studied in terms of correlations between the outgoing protons. It is observed there is more $\rho^{0}$(770) and \fmeson production in reactions where the outgoing protons %fastest and slowest particles in the laboratory frame are on opposite sides of the beam. This effect is not attributable to the trigger or the experimental acceptance, and suggests that the vertices do not factorise.

Published
1996
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26. Study of charged particle production using Omega RICH in WA94 experiment

Author

B. R. French, W. Beusch, A. Volte, V. Lenti, R. Sené, M. Benayoun, Ivan Kralik, Petr Zavada, R. A. Loconsole, Ph. Leruste, M. Morando, N. Carrer, S. Abatzis, F. Pellegrini, T.F. Thorsteinsen, O. Villalobos Baillie, R. A. Ricci, Federico Antinori, J. L. Narjoux, E. Andersen, V. A. Katchanov, D. Di Bari, A. C. Bayes, J.B. Kinson, B. Ghidini, A. Jacholkowski, M. Sené, Alberto Andrighetto, Vito Manzari, A. Kirk, J. C. Lassalle, R. A. Fini, D. Elia, K. Fanebust, J. Kahane, A. V. Singovsky, David H. Evans, K. Knudson, P. Ladron de Guevara, G.F. Segato, F. Navach, R. P. Barnes, J. N. Carney, E. Quercigh, J. P. Davies, L. Sandor, Roman Lietava, A.K. Holme, J. Bohm, M. Venables, Jozef Urban, K. Šafařík, Håvard Helstrup, B. De La Cruz, G. Vassiliadis, G. Løvhøiden, and M.F. Votruba

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, Tracking (particle physics), Omega, Charged particle, Particle identification, Particle detector, Nuclear physics, Particle, High Energy Physics::Experiment, Nuclear Experiment, Nucleon, Charged particle beam, Instrumentation
Abstract

We present preliminary results about charged particle production in SS collisions at 200 GeV/ c per nucleon, obtained by WA94 experiment at CERN-SPS. The particle identification has been provided by the Omega RICH; a silicon telescope and an array of multiwire proportional chambers (MWPC) have been used to track particles to the RICH detector. Details about particle tracking and identification procedure are also reported.

Published
1996
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27. Production of strange and multistrange hyperons and antihyperons in S-W interactions at 200 GeV/c per nucleon

Author

Leonardo Paolo Rossi, A. Kirk, D. Di Bari, Håvard Helstrup, B. De La Cruz, A. C. Bayes, A. Jacholkowski, S. Abatzis, R. A. Fini, O. Villalobos Baillie, G. Vassiliadis, Vito Manzari, J. P. Davies, David H. Evans, J. Kahane, V. Lenti, J. L. Narjoux, B. Ghidini, R. P. Barnes, K. Knudson, E. Quercigh, J. N. Carney, K. Šafařík, A. Volte, F. Navach, R. Sené, Federico Antinori, A. Andrighetto, W. Beusch, J.B. Kinson, M. Benayoun, M. Sené, M.F. Votruba, J. P. Dufey, R. A. Loconsole, D. Elia, B. R. French, Ph. Leruste, A.K. Holme, J. C. Lassalle, and T. Storås

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, High Energy Physics::Phenomenology, Nuclear Theory, Hadron, Hyperon, Spectral line, Nuclear physics, Baryon, Transverse mass, High Energy Physics::Experiment, Heavy ion, Nuclear Experiment, Nucleon
Abstract

Strange and multistrange baryon and antibaryon production is a useful probe into the dynamics of the hot hadronic matter created in central heavy ion interactions. Relative production yields and transverse mass spectra are presented for Λ, Λ, Ξ− and Ξ+ hyperons produced in central sulphur-tungsten interactions at 200 GeV/c per nucleon.

Published
1995
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28. Measurement of the lifetime

Author

M.I. Adamivich, E. Albertson, Yu.A. Alexandrov, D. Barberis, M. Beck, C. Bérat, W. Beusch, M. Boss, S. Brons, W. Brückner, M. Buénerd, C. Büscher, F. Charignon, J. Chauvin, E. Chudakov, F. Dropmann, J. Engelfried, F. Faller, A. Fournier, S.G. Gerassimov, M. Godbersen, P. Grafström, Th. Haller, M. Heidrich, R.B. Hurst, K. Königsmann, I. Konorov, K. Martens, Ph. Martin, S. Masciocchi, R. Michaels, U. Müller, S. Paul, B. Povh, Z. Ren, M. Rey-Campagnolle, G. Rosner, L. Rossi, H. Rudolph, L. Schmitt, H.-W. Siebert, A. Simon, V.J. Smith, O. Thilmann, A. Trombini, E. Vesin, B. Volkemer, K. Vorwalter, Th. Walcher, G. Wälder, R. Werding, E. Wittmann, M.V. Zavertyaev, and C. Newaom

Subjects
Physics, Nuclear and High Energy Physics, chemistry, 010308 nuclear & particles physics, 0103 physical sciences, Metallurgy, chemistry.chemical_element, 010306 general physics, 01 natural sciences, Carbon, Copper
Published
1995
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29. A further study of the centrally produced π+π− and π+π−π+π− channels in pp interactions at 300 and 450 GeV/c

Author

Irakli Minashvili, Federico Antinori, A. Jacholkowski, N.A. Russakovich, Y. Kulchitsky, G. Vassiliadis, C. J. Dodenhoff, B. Ghidini, Paolo Martinengo, R. A. Loconsole, R. A. Fini, K.L. Norman, J. P. Davies, D. Barberis, B. R. French, G. Tchlatchidze, M.F. Votruba, V. Lenti, D. Elia, F. Navach, J.B. Kinson, A. Solovjev, O. Villalobos Baillie, A. Kirk, David H. Evans, A. Semenov, E. Quercigh, M. Sené, R. Sené, A. C. Bayes, Vito Manzari, J. N. Carney, W. Beusch, V. Romanovsky, S. Clewer, S. Maljukov, and D. Di Bari

Subjects
Physics, Crystal, Nuclear and High Energy Physics, Mass spectrum, Atomic physics, Central region, Omega, Particle Physics - Experiment
Abstract

An analysis of the centrally produced π + π − and π + π − π + π − mass spectra from the WA76 and WA91 experiments is presented, which shows that in the π + π − π + π − channel there are two new states, the f 0 (1450) and f 2 (1900). There is another new state in the π + π − channel with M = 1497 ± 30 MeV and Γ = 199 ± 30 MeV, which is compatible with the f 0 (1520) observed by the Crystal Barrel experiment. Another interpretation is discussed, where the 1450 and 1497 GeV structures are explained as being due to an interference effect between the f 0 (1365) and f 0 (1520).

Published
1995
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30. Strange particle production in sulphur-sulphur interactions at 200 GeV/c per nucleon

Author

U. Mueller, Håvard Helstrup, B. De La Cruz, G. Vassiliadis, M. Morando, R. A. Loconsole, A.K. Holme, V. Manzari, K. Šafařík, A. V. Singovsky, M. Passaseo, R. Fini, A. Kirk, A. Jacholkowski, J. P. Dufey, J. C. Lassalle, V. A. Katchanov, G. Waelder, Jürgen Engelfried, Ph. Leruste, V. Lenti, K. Knudson, P. Ladron de Guevara, J. N. Carney, D. Elia, Jozef Urban, D. Di Bari, J. Kahane, K. Martens, I. J. Bloodworth, W. Beusch, J. L. Narjoux, A. Michalon, A. Bravar, M. Benayoun, F. Navach, J. Bohm, R. Sené, C. Voltolini, Alberto Andrighetto, G. Løvhøiden, G.F. Segato, E. Quercigh, G. Undheim, A. Volte, S. Abatzis, L. Šándor, F. Pellegrini, R. Blaes, Petr Zavada, B. Ghidini, J.B. Kinson, M. Sené, S. Clewer, David H. Evans, C.J. Dodenhoff, T.F. Thorsteinsen, O. Villalobos Baillie, R. A. Ricci, R. P. Barnes, A. C. Bayes, M.F. Votruba, H. W. Siebert, B. R. French, Federico Antinori, J. P. Davies, Aldo Penzo, T. Kachelhoffer, Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), WA94, Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Heyd, Yvette

Subjects
Physics, Nuclear and High Energy Physics, Strange quark, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], Plasma formation, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Nuclear Theory, chemistry.chemical_element, 01 natural sciences, Central region, Omega, Sulfur, Baryon, Nuclear physics, chemistry, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Transverse mass, Nuclear Experiment, 010306 general physics, Nucleon
Abstract

Multi-strange baryon and anti-baryon production is expected to be a useful probe in the search for Quark-Gluon Plasma formation. We present the transverse mass distributions of negative particles, K o s, Λs, Λ s, and Ξ − s produced in sulphurtungsten interactions at 200 GeV/c per nucleon and give the corrected ratios Λ Λ, Ξ − Λ and Ξ − /Λ . We note that our ratio Ξ − / Λ appears large in comparison to that from p p interactions.

Published
1995
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31. Results on the production of baryons with |S| = 1, 2, 3 and strange mesons in S-W collisions at 200 GeV/c per nucleon

Author

T. Storås, Domenico Di Bari, A. C. Bayes, Federico Antinori, A. Jacholkowski, R. P. Barnes, J. P. Davies, V. Manzari, Leonardo Paolo Rossi, A. Kirk, E. Quercigh, B. R. French, K. Šafařík, A. Volte, R. Sené, O. Villalobos Baillie, J. Kahane, W. Beusch, A.K. Holme, B. Ghidini, A. Andrighetto, M. Benayoun, F. Navach, Håvard Helstrup, B. De La Cruz, J. L. Narjoux, R. Fini, G. Vassiliadis, J.B. Kinson, V. Lenti, K. Knudson, J. N. Carney, J. C. Lassalle, M. Sené, David H. Evans, D. Di Bari, M.F. Votruba, J. P. Dufey, D. Elia, S. Abatzis, and Ph. Leruste

Subjects
Nuclear physics, Baryon, Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Meson, Production (computer science), Rapidity, Strangeness, Nucleon
Abstract

We report results on the production of strange baryons/antibaryons with 1, 2, and 3 units of strangeness (Λ, Ξ and Ω) and mesons (K s 0 , K + and K − ) in WA85 experiment at the CERN SPS. This experiment was designed to study the production of strange particles in central SW collisions at 200 GeV/c per nucleon, in the central rapidity region with medium to high p t . We have measured the inverse slopes of the m t distributions of such particles and the production ratios Λ /Λ, Ξ + /Ξ − , Ξ − / Λ , Ξ + / Λ , K s 0 / Λ , K s 0 / Λ , (Ω − + Ω + ) (Ξ − + Ξ + ) and K + K − . Preliminary results on the production ratios Ξ − / Λ and Ξ + / Λ in pW collisions at 200 GeV/c are also presented.

Published
1995
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32. Results on charmed meson decay from the WA82 experiment at the CERN omega spectrometer

Author

E. Lamanna, R. Hurst, P. Netchaeva, A. Jacholkowski, B. R. French, D. Barberis, A. Kirk, A. Forino, Bianca Osculati, M. Weymann, Patrick Legros, P. Mazzanti, Fernand Grard, Federico Antinori, V. Casanova, M. Davenport, R. Gessaroli, J. C. Lassalle, Leonardo Paolo Rossi, J. P. Dufey, K. Harrison, G. Tomasini, M. V. Zavertyaev, Yu. Alexandrov, W. Beusch, M. I. Adamovich, A. Quareni, Chiara Roda, N. Radaelli, F. Muller, A. Buys, and M. Dameri

Subjects
Physics, Particle physics, Large Hadron Collider, Meson, Spectrometer, Physics::Instrumentation and Detectors, Branching fraction, High Energy Physics::Phenomenology, Omega, Particle identification, Ring-imaging Cherenkov detector, Nuclear physics, High Energy Physics::Experiment, Impact parameter, Nuclear Experiment
Abstract

The WA82 experiment has collected data with the Ω′ spectrometer at the CERN SPS. Its aim was a high-statistics study of charm hadroproduction, using a silicon microstrip vertex detector and a trigger on impact parameter. WA82 is also studying rare decay modes for charm. Latest results on non-leptonic charmed meson decay branching ratios are presented here, including the study of doubly Cabibbo-suppressed modes for D+. This analysis, using the particle identification provided by a Ring Imaging CHerenkov detector (RICH), gives an indication for a new decay mode, D+→K-K+K+. An upper limit for the D+→K+π-π+ mode branching ratio is also obtained.

Published
1994
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33. First results from experiment WA91 at the CERN omega spectrometer

Author

Irakli Minashvili, G. Vassiliadis, D. Barberis, N.A. Russakovich, A. Solovjev, I. Vichou, A. Jacholkowski, V. Lenti, A. C. Bayes, G. Tchlatchidze, Vito Manzari, W. Beusch, V. Romanovsky, A. Semenov, Maria Girone, M. Sené, B. Ghidini, J.B. Kinson, F. Navach, R. Sené, S. Maljukov, J. N. Carney, A. Loconsole, D. Di Bari, M.F. Votruba, A. Kirk, O. Villalobos Baillie, R. P. Barnes, C. J. Dodenhoff, J. P. Davies, S. Clewer, D. Evans, E. Quercigh, R. A. Fini, Federico Antinori, and B. R. French

Subjects
Physics, Nuclear physics, Particle physics, Large Hadron Collider, Meson, Spectrometer, Omega, Central region, Particle Physics - Experiment, Bar (unit)
Abstract

Experiment WA91 searches for non-\(q\bar q\) mesons produced in the central region in the reaction pp→pf(X0)ps at 450 GeV/c using the CERN Omega Spectrometer. WA91 is a continuation of the WA76 experiment which has studied this reaction using beams of 85 and 300 GeV/c. Preliminary results from experiment WA91 are presented. In particular the X(1450) and X(1900) observed for the first time in the π+π-π+π- channel of the WA76 experiment at 300 GeV/c are confirmed by the WA91 data.

Published
1994
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34. Development of a pixel readout chip compatible with large area coverage

Author

G. Meddeler, Pierre Jarron, J. Heuser, C. Neyer, Federico Antinori, T. Karttaavi, Erik H.M. Heijne, E. Quercigh, P. Middelkamp, W. Beusch, F. Pengg, H. Beker, Michael Campbell, L. Lopez, M. Pindo, H. Verweij, S. Simone, Francois Krummenacher, A. Menetrey, and E. Chesi

Subjects
Physics, Nuclear and High Energy Physics, Pixel, business.industry, Clock rate, Detector, Integrated circuit, Chip, Noise (electronics), Particle detector, law.invention, law, Optoelectronics, business, Instrumentation, Electronic circuit
Abstract

A second version of the Omega pixel readout chip has been developed in order to make it compatible with large area coverage. Specific features of the new chip include a reset which can be applied immediately following a “false” trigger, an improved minimum strobe time of ∼ 100 ns, a readout clock rate of ∼ 20 MHz and tri-state buffers on the output data lines. The excellent performance figures of the first chip for noise (100 e rms without detector and 170 e rms with detector) and power consumption (30 μW/pixel) have been maintained. We demonstrate how with solder bump-bonding we can create hybrid “ladders” which hermetically cover an area of ∼ 5 mm × 50 mm. Potential problems of electrical matching and yield have been addressed and procedures are in place for selecting only “good” readout chips for mounting.

Published
1994
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35. Ω− signal in WA85

Author

J. P. Dufey, O. Villalobos Baillie, K. Knudson, J. N. Carney, D. Elia, Maria Girone, Leonardo Paolo Rossi, M.F. Votruba, B. De La Cruz, A. Jacholkowski, V. Lenti, S. Abatzis, A. Volte, Haavard Helstrup, J. Kahane, A. Kirk, W. Beusch, A. C. Bayes, R. Sené, A.K. Holme, B. Ghidini, M. Benayoun, Vito Manzari, R. P. Barnes, Ph Leruste, F. Navach, A. Bravar, K. Šafařík, Alberto Andrighetto, M. Sene, Federico Antinori, J. C. Lassalle, J.B. Kinson, A. Penzo, D. Di Bari, D. Evans, B. R. French, E. Quercigh, J. L. Narjoux, R. A. Fini, J. P. Davies, and G. Vassiliadis

Subjects
Physics, Nuclear and High Energy Physics, Particle decay, Branching fraction, Hadron, Analytical chemistry, Mass spectrum, Rapidity, Lambda baryon, Omega baryon, Xi baryon
Abstract

We have extracted from the full WA85 1990 data set a sample of 14ω − + ω − candidates. We describe the selection criteria, and give a measurement of the ω − /ω − ratio at central rapidity and PT > 1.6 GeV/c.

Published
1994
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36. Strange particle production in sulphur-sulphur interactions at 200 per nucleon

Author

C.J. Dodenhoff, J. C. Lassalle, S. Abatzis, V. Lenti, K. Martens, A. C. Bayes, Vito Manzari, G.F. Segato, F. Pellegrini, K. Šafařík, E. Quercigh, B. R. French, R. P. Barnes, A. Kirk, J.B. Kinson, A. V. Singovsky, M.F. Votruba, A. Volte, A.K. Holme, M. Passaseo, C. Voltolini, R. Sené, Aldo Penzo, R. A. Fini, Alberto Andrighetto, A. Michalon, O. Villalobos Baillie, R. A. Ricci, H. W. Siebert, G. Undheim, T.F. Thorsteinsen, L. Sandor, A. Jacholkowski, U. Mueller, Federico Antinori, Haavard Helstrup, R. Blaes, Petr Zavada, B. De La Cruz, S. Clewer, J. P. Dufey, D. Di Bari, D. Elia, I. J. Bloodworth, R. A. Loconsole, V. A. Katchanov, A. Bravar, J-L. Narjoux, David H. Evans, M. Morando, J. Kahane, G. Waelder, G. Vassiliadis, Gunnar Løvhøiden, Jürgen Engelfried, M. Sené, K. Knudson, P. Ladron de Guevara, J. N. Carney, J. Urban, J. Bohm, W. Beusch, M. Benayoun, B. Ghidini, F. Navach, Ph Leruste, J. P. Davies, and T. Kachelhoffer

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Strange quark, chemistry, chemistry.chemical_element, Nucleon, Sulfur
Published
1994
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37. New results from WA85 on multistrange hyperon production in 200 A S-W interactions

Author

Maria Girone, V. Lenti, Federico Antinori, D. Evans, J. P. Dufey, D. Elia, R. P. Barnes, D. Di Bari, W. Beusch, G. Vassiliadis, M. Benayoun, J. P. Davies, A. Volte, B. Ghidini, S. Abatzis, Haavard Helstrup, A.K. Holme, R. A. Fini, A. Bravar, B. de la Cruzy, Alberto Andrighetto, R. Sené, F. Navach, J. Kahane, M. Sene, A. C. Bayes, A. Kirk, E. Quercigh, J. C. Lassalle, Vito Manzari, A. Jacholkowski, B. R. French, M.F. Votruba, Leonardo Paolo Rossi, Karel Safarik, J.B. Kinson, A. Penzo, J. L. Narjoux, O. Villalobos Baillie, K. Knudson, Ph Leruste, and J. N. Carney

Subjects
Physics, Nuclear and High Energy Physics, Particle decay, Particle physics, Meson, Hadron, Hyperon, Lambda baryon, Omega baryon, Xi baryon, Boson
Published
1994
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38. Transverse momentum distributions for meson resonances at central rapidity andP T≧2 GeV/c

Author

A. Kirk, G. Vassiliadis, J. Kahane, V. Lenti, E. Quercigh, M.F. Votruba, K. Knudson, I. J. Bloodworth, J. N. Carney, B. R. French, K. Šafařík, C. Evangelista, B. Ghidini, F. Navach, I. Vichou, Ph. Leruste, A. Malamant, R. A. Fini, A. Belogianni, W. Beusch, J. L. Narjoux, A. Jacholkowski, M. Benayoun, M. T. Trainor, M. Sené, D. Di Bari, R. Zitoun, R. Sené, J.B. Kinson, Vito Manzari, O. Villalobos Baillie, and M. Stassinaki-Spyropoulou

Subjects
Physics, Nuclear reaction, Particle physics, Physics and Astronomy (miscellaneous), Meson, Hadron, Quarkonium, Nuclear physics, Particle decay, Pair production, Pion, High Energy Physics::Experiment, Rapidity, Nuclear Experiment, Engineering (miscellaneous), Particle Physics - Experiment
Abstract

The transverse momentum distributions for\(\rho ^0 (770),f_2 (1270),K*^0 (892),\bar K*^0 (892)\) and ϕ (1020) have been studied in thept region between 2 and 4 GeV/c and central rapidity. The data analysed come from the WA77 experiment at CERN with a 300 GeV/c π− beam incident on a Be target. These distributions are well described by the functionpt−n withn∼8. A sample of simulated events from the Lund Monte Carlo in the same experimental conditions reproduces well the data.

Published
1993
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39. The RICH counter in the CERN hyperon beam experiment

Author

Jürgen Engelfried, W. Beusch, P. Lennert, Joachim Heintze, G. Wälder, H. W. Siebert, S.G. Gerassimov, S. Kluth, H. Rieseberg, U. Müller, K. Martens, S. Ljungfelt, and R. Michaels

Subjects
Physics, Wire chamber, Nuclear and High Energy Physics, Photon, Large Hadron Collider, Atmospheric pressure, Physics::Instrumentation and Detectors, Hyperon, Photoelectric effect, Charged particle, Particle detector, Nuclear physics, Volume (thermodynamics), Measuring instrument, High Energy Physics::Experiment, Detectors and Experimental Techniques, Atomic physics, Instrumentation, Cherenkov radiation, Beam (structure)
Abstract

The hyperon beam experiment WA89 at the CERN-SPS uses a ring imaging Cherenkov counter (RICH) for identification of secondaries from ∑ − N reactions. Cherenkov photons are generated in a 5 m long radiator volume filled with nitrogen at atmospheric pressure and detected in drift chambers. The drift chambers cover an active surface of 1.6 × 0.75 m 2 , with a maximum drift path of 41 cm. Photoelectrons are counted on 1280 wires with a pitch of 2.54 mm, equipped with multihit TDCs. The counting gas is ethane saturated with TMAE at 30°C. The counter was operated in two beam periods in 1990 and 1991. The spatial resolution of the chambers is better than 2 mm and under normal running conditions 14 photoelectrons per ring have been detected on average.

Published
1992
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40. Study of theπ + π − γ system centrally produced in the reactionpp→p f (π + π − γ)p s at 300 GeV/c

Author

A. Kirk, O. Villalobos Baillie, G. Vassiliadis, K. Knudson, D. Evans, J. N. Carney, Maria Girone, B. R. French, R. Sené, E. Quercigh, T. A. Armstrong, A. Palano, M. Sené, C. J. Dodenhoff, D. DiBari, J.B. Kinson, I. J. Bloodworth, V. Lenti, R. P. Barnes, W. Beusch, M. Benayoun, A. Jacholkowski, M.F. Votruba, C. Evangelista, B. Ghidini, F. Navach, and Vito Manzari

Subjects
Physics, Physics and Astronomy (miscellaneous), Branching fraction, Mass spectrum, Atomic physics, Engineering (miscellaneous)
Abstract

The reactionpp→pf(π+π−γ)ps, where theπ+π−γ system is centrally produced, has been studied at 300 GeV/c. Theπ+π−γ mass spectrum shows evidence for aρ0γ decay mode of theη′ (958) andf1 (1285). The branching ratio (f1(1285)→ηπ+π+)/(f1(1285)→ρ0γ) is found to be 5.0±0.7. No evidence is found for aρ0(770)γ decay mode of theE/f1 (1420) for which an upper limit BR (E/f1(1420)→ρ0γ)

Published
1992
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41. Results on charm physics from WA82

Author

N. G. Redaelli, A. Brunengo, G. Tomasini, V. Casanova, M. Davenport, A. Jacholkowski, R. Gessaroli, W. Beusch, S. Gerasimov, R. Hurst, Patrick Legros, Leonardo Paolo Rossi, P. Nechaeva, P. Mazzanti, Fernand Grard, A. Kirk, Bianca Osculati, D. Barberis, F. Muller, J. C. Lassalle, M. Demeri, J. P. Dufey, Yu. Alexandrov, Federico Antinori, B. R. French, P. Viaggi, M. I. Adamovich, A. Quareni, A. Forino, S. P. Kharlamov, A. Buys, and M. V. Zavertyaev

Subjects
Mass number, Scattering cross-section, Physics, Semileptonic decay, Nuclear and High Energy Physics, Particle physics, Meson, Proton, Nuclear Theory, High Energy Physics::Phenomenology, Measure (physics), Atomic and Molecular Physics, and Optics, Nuclear physics, Physics::Accelerator Physics, High Energy Physics::Experiment, Charm (quantum number), Nuclear Experiment, Beam (structure)
Abstract

Experiment WA82 studies the hadroproduction of charmed mesons with a 340 GeV/c pion beam and a 370 GeV/c proton beam. The high and clean statistics of collected charms has been used to measure the differential cross section and its dependence on target nucleon number. The analysis of semileptonic decay D→K ∗ eν is presented.

Published
1992
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42. Use of a high-resolution, scintillating-fibre, tracking detector in recording π−-nucleon interactions at √s ≈ 26 GeV

Author

K. Harrison, D. Lucchesi, V. Flaminio, Chiara Roda, J.G. McEwen, W. Beusch, A. Duane, G. Martelloti, M. Adinolfi, Alessandro Cardini, D. Websdale, E. Lamanna, Jean-Paul Fabre, A. Sciubba, Gianni Penso, M. De Vincenzi, D. Crennell, Corrado Angelini, D. R. O. Morrison, and A. Frenkel

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Spectrometer, Physics::Instrumentation and Detectors, business.industry, Detector, Tracking (particle physics), Particle detector, Semiconductor detector, Optics, High Energy Physics::Experiment, Nuclear Experiment, business, Instrumentation, Event (particle physics), Event reconstruction
Abstract

A scintillating-microfibre, tracking detector has been used at the CERN Omega spectrometer to record the interactions of 340 GeV/ cπ − particles incident on a fixed target. The detector - based on coherent bundles of ∼36 μ m diameter, PMP-doped plastic fibres - was oriented so as to give views of interactions in the plane perpendicular to the incoming pions. Additional event information was provided by a series of 20 and 50 μm pitch silicon-microstrip detectors, placed near to the fibres, and by the spectrometer. An account is given of the contribution of the scintillating-fibre device in obtaining full event reconstruction.

Published
1992
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43. Measurement of relative branching fractions of D° Cabibbo-suppressed decays

Author

B. R. French, Federico Antinori, M. V. Zavertyaev, W. Beusch, S. Gerasimov, P. Nechaeva, F. Viaggi, R. Gessaroli, M. Davenport, A. Forino, F. Muller, A. Jacholkowski, M. I. Adamovich, M. Dameri, A. Kirk, J. C. Lassalle, Leonardo Paolo Rossi, A. Quareni, D. Barberis, Fernand Grard, P. Mazzanti, J. P. Dufey, Patrick Legros, R. Hurst, N. Redaelli, Yu. Alexandrov, Chiara Meroni, Bianca Osculati, G. Tomasini, A. Buys, and D. Torretta

Subjects
Physics, Nuclear and High Energy Physics, Quantum electrodynamics, Analytical chemistry, Branching (polymer chemistry), Omega
Abstract

The decay modes D0→K−π+, K−K+, π−π+, K−π−π+π+ and π−π−π+π+ have been studied by the hadroproduction experiment WA82. The following ratios of branching fractions have been measured: B(D0→K−K+)B(D0→π−π+)=2.23±0.81±0.46, B(D0→K−K+)B(D0→K−π+)=0.107±0.029±0.015, B(D0→π−π+)B(D0→K−π+)=0.048±0.013±0.008, B(D0→π−π−π+π+)B(D0→K−π−π−π+π+)=0.115±0.023±0.016.

Published
1992
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44. Application of a scintillating-fibre detector to the study of short-lived particles

Author

Gianni Penso, Corrado Angelini, G. Di Vita, M. Adinolfi, Federico Antinori, J.G. McEwen, A. Duane, G. Martelloti, Thierry Gys, Jean-Paul Fabre, C. Da Via, M. De Vincenzi, A. Sciubba, D. Lucchesi, S. Petrera, M.C. Di Paolo, A. Frenkel, Alessandro Cardini, O. Villalobos-Baillie, David Websdale, W. Beusch, D. Crennell, Chiara Roda, V. Flaminio, D. R. O. Morrison, K. Harrison, and E. Lamanna

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Physics::Instrumentation and Detectors, business.industry, Detector, Elementary particle, Tracking (particle physics), Particle detector, Particle decay, Optics, Scintillation counter, Particle, business, Instrumentation
Abstract

The technique of particle tracking with scintillating fibres is described and its application to the study of short-lived particles is illustrated using results obtained in the WA84 experiment at CERN.

Published
1991
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45. production in sulphur-tungsten interactions at 200 GeV/c per nucleon

Author

S. Abatzis, M.F. Votruba, K. Šafařík, A. Bravar, V. Lenti, K. Knudson, J. N. Carney, J. Kahane, I. J. Bloodworth, Federico Antinori, M. Tamazouzt, M. T. Trainor, V. Manzari, R. Fini, J.B. Kinson, A. Penzo, R. P. Barnes, M. Sené, A. Palano, J. C. Lassalle, A. Jacholkowski, A. Volte, B. De La Cruz, G. Vassiliadis, R. Sené, A. Kirk, J. P. Dufey, R. A. Loconsole, L. Lima Frances, O. Villalobos Baillie, Ph. Leruste, B. R. French, M. Girone, Leonardo Paolo Rossi, A.K. Holme, J. L. Narjoux, Haavard Helstrup, B. Ghidini, David H. Evans, W. Beusch, M. Benayoun, F. Navach, E. Quercigh, A. Malamant, and D. Di Bari

Subjects
Physics, Nuclear and High Energy Physics, Plasma formation, Nuclear Theory, chemistry.chemical_element, Tungsten, Omega, Sulfur, Baryon, Nuclear physics, chemistry, Quark–gluon plasma, Transverse mass, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, Nucleon
Abstract

Multi-strange baryon and antibaryon production is expected to be a useful probe in the search for quark-gluon plasma formation. We present the transverse mass distributions of negative particles, Λ' s , Λ ' s and Ξ − ' s produced in sulphur-tungsten interactions at 200 GeV/c per nucleon and give the corrected rations Λ /Λ, Ξ − /Λ and Ξ − / Λ . Our ratio Ξ − / Λ appears to be larger than that from pp interactions.

Published
1991
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46. A microstrip vertex detector for studying charm hadroproduction

Author

J. C. Lassalle, Leonardo Paolo Rossi, A. Jacholkowski, J. P. Dufey, B. R. French, F. Viaggi, D. Barberis, Chiara Meroni, Paolo Martinengo, E. Torassa, Pierre Jarron, Patrick Legros, Federico Antinori, R. Hurst, Erik H.M. Heijne, S. Gerasimov, M. Davenport, R. Gessaroli, Bianca Osculati, F. Bourgeois, P. Mazzanti, Fernand Grard, A. Buys, A. Kirk, A. Forino, L. Malferrari, M. I. Adamovich, G. Tomasini, A. Quareni, Yu. Alexandrov, M. V. Zavertyaev, F. Muller, W. Beusch, M. Dameri, and N. Redaelli

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Hadron, Microstrip, Magnetic field, Vertex (geometry), law.invention, Nuclear physics, Telescope, Transverse plane, law, High Energy Physics::Experiment, Impact parameter, Nuclear Experiment, Instrumentation
Abstract

The WA82 experiment has collected data at the Ω facility at CERN for the study of charmed particles produced in hadronic interactions. In order to select charmed particles in the much larger background of ordinary hadronic interactions precise reconstruction of tracks in high-multiplicity events is necessary. The required accuracy, 10 μm in the transverse plane, has been obtained with a telescope made of 23 silicon microstrip detectors, with pitch ranging from 10 to 50 μm. This telescope has been operated in a 1.3 T magnetic field and has been specially designed to select on-line events with secondary vertices. The trigger, based on the measurement of the impact parameter of a track relative to the primary vertex, enriched the charm sample by a factor 15.

Published
1991
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47. Study of the centrally producer ?? andK $$\bar K$$ systems at 85 and 300 GeV/c

Author

W. Beusch, M. Benayoun, R. Childs, A. Malamant, A. Jacholkowski, Ph. Leruste, K. Knudson, J.B. Kinson, B. R. French, J. N. Carney, M.F. Votruba, J. Kahane, C. Evangelista, B. Ghidini, V. Lenti, N. G. Redaelli, A. Palano, Maria Girone, A. Kirk, Leonardo Paolo Rossi, E. Quercigh, M. Stassinaki, F. Navach, T. A. Armstrong, R. Sené, I. J. Bloodworth, J. L. Narjoux, O. Villalobos Baillie, G. Vassiliadis, M. T. Trainor, and M. Sené

Subjects
Particle acceleration, Physics, Nuclear physics, Formalism (philosophy of mathematics), Large Hadron Collider, Physics and Astronomy (miscellaneous), Spectrometer, Mass spectrum, Elementary particle, Quantum field theory, Atomic physics, Engineering (miscellaneous)
Abstract

We have studied the ππ andK\(\bar K\) systems centrally produced in proton proton collisions at 300 GeV/c and π+/p proton collisions at 85 GeV/c using the CERN Ω spectrometer. Clear evidence forS*/fo(975) production is observed. An analysis performed on the π+ π− mass spectrum in the 1.0 GeV region, using a coupled channel formalism, shows that it is possible to describe theS*/fo(975) effect with one single resonance once interference of theS*/fo(975) with theS-wave background is introduced. The resultingS*/fo(975) parameters aremo=979±4MeV,gπ=0.28±0.04,gK=0.56±0.18 corresponding to a pole position on sheet II at (1001±2)−i(36±4) MeV. Evidence is also found for a structure having a mass of 1472±12 MeV and a width of 195±33 MeV.

Published
1991
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48. Study of the ηπ+π− system centrally producedin the reactionpp→p f (ηπ+π−)p s at 300 GeV/c

Author

W. Beusch, M. Benayoun, I. J. Bloodworth, K. Knudson, M.F. Votruba, J. N. Carney, A. Palano, A. Jacholkowski, David H. Evans, V. Lenti, A. Kirk, D. DiBari, G. Vassiliadis, Maria Girone, O. Villalobos Baillie, T. A. Armstrong, C. J. Dodenhoff, J.B. Kinson, Vito Manzari, E. Quercigh, C. Evangelista, B. Ghidini, B. R. French, M. Sené, F. Navach, R. Sené, and R. P. Barnes

Subjects
Momentum, Pseudoscalar, Nuclear physics, Particle acceleration, Physics, Physics and Astronomy (miscellaneous), Spectrometer, Meson, Mass spectrum, Elementary particle, Engineering (miscellaneous), Omega
Abstract

The reactionpp→pf(ηπ+π−)ps where the ηπ+π− system is centrally produced has been studied at 300 GeV/c incident momentum at the CERN Ω spectrometer. The ηπ± mass spectrum shows a strong δ/a0(980) signal having a mass of 984±4 and Γ=95±14 MeV. The ηπ+π− mass spectrum shows η′ andf1(1285) signals over little background. A spin-parity analysis of the ηπ+π− system shows evidence for aJPC=1++ peak at thef1(1285) mass but no evidence for the pseudoscalar states η(1270) andl/η(1440). No evidence is found for the ηππ decay of theE/f1(1420) meson for which we set an upper limit BR(E/f1(1420)→ηππ)

Published
1991
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49. Λ and anti-Λ production in 32S + W and p + W interactions at 200 A GeV/c

Author

R. Zitoun, V. Lenti, K. Knudson, J. N. Carney, M. T. Trainer, B. R. French, David H. Evans, I. J. Bloodworth, K. Manzari, A. Malamant, B. Ghidini, A. Jacholkowski, E. Quercigh, S. Abatzis, R. A. Loconsole, A. Bravar, W. Beusch, R. P. Barnes, Ph. Leruste, A. Volte, M. Benayoun, F. Navach, R. Sené, J. Kahane, A. Kirk, R. Fini, J. C. Lassalle, O. Villalobos Baillie, M. Tamazouzt, L. Lima Frances, J.B. Kinson, A. Penzo, J. P. Dufey, A. Palano, M. Stassinaki, M. Sené, M.F. Votruba, Leonardo Paolo Rossi, J. L. Narjoux, and G. Vassiliadis

Subjects
Nuclear reaction, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle decay, Meson, Hadron, Hyperon, Nucleon, Lambda baryon, Boson
Published
1991
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50. Preliminary results on direct soft photon production in π−p interactions at 280 GeV/c

Author

M. Grabowski, G.W. Wilson, A. Weigend, P. Sonderegger, K. Knudson, U. Kerres, J.A.G. Morris, Irene Vichou, A. Belogianni, B. R. French, G. Vassiliadis, E. Quercigh, A. Subramanian, W. Beusch, Yves Goldschmidt-Clermont, M. Spyropoulou-Stassinaki, Sw. Banerjee, T.J. Brodbeck, Dario Barberis, and S. Abatzis

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Soft photon
Published
1991
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