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51. A new search for relativistic particles with fractional electric charge at the CERN collider

Author

P. A. Dorsaz, Peter Jenni, H. Hänni, Valerio Vercesi, J. M. Gaillard, Daniel Froidevaux, G. Parrour, J. P. Repellin, H. Plothow-Besch, F. Stocker, G. Sauvage, T. Himel, Allan G Clark, P. Mani, J. C. Chollet, Fr. Pastore, A. F. Rothenberg, S. Loucatos, M. Borghini, M. Banner, O. Gildemeister, Marco Fraternali, Michele Livan, R. Mollerud, V.G. Goggi, W. Zeller, B. Madsen, Louis Fayard, C. Onions, John H. L. Hansen, H. Zaccone, C. Conta, K. Borer, B. Hahn, P. H. Hansen, P. Darriulat, J. Teiger, L. Di Lella, Livio Mapelli, J. Schacher, J. Dines-Hansen, A. Roussarie, J. L. Siegrist, B. Merkel, O. Kofoed-Hansen, Ph. Bloch, Giancarlo Mantovani, and B. Mansoulié

Subjects
Physics, Quark, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Charge (physics), Electric charge, Charged particle, law.invention, Relativistic particle, Nuclear physics, law, Ionization, Collider
Abstract

We report on a search for relativistic particles with fractional electric charge at the CERN p p colider, using a telescope of scintillation counters to detect particles with anomalously low ionization. Since no event survives the selection criteria, upper limits on quark production are deduced from this experiment. At 90% confidence level and in the limit of very light quarks with charge ± 1 2 and ± 2 3 they are 2.8×10 −6 and 5.6×10 −5 , respectively, per single charged particle. These limits increase rapidly with increasing quark mass and are nearly two and one order of magnitude better than previously measured by UA2.

Published
1985

52. Direct photon production at the CERN p̄p collider

Author

P. Cenci, Eric Lancon, Marco Fraternali, Peter Hansen, G. Sauvage, A. R. Weidberg, M. Banner, H. Zaccone, C. Onions, S.N. Tovey, J. A. Appel, N. Harnew, Livio Mapelli, R. Mollerud, K. Meier, Kevin Einsweiler, M. Borghini, E. E. Kluge, Louis Fayard, J. C. Chollet, John H. L. Hansen, C. Conta, T. Himel, B. Hahn, M. Morganti, Allan G Clark, P. Mani, G. Parrour, Claus Gössling, B. Merkel, Roberto Battiston, M. Pepe, M. Schlötelburg, J. Teiger, M. Wunsch, Lydia Iconomidou-Fayard, V. G. Goggi, Melody A. Swartz, S. Loucatos, Giovanni Carboni, M. Valdata-Nappi, W.Y. Tsang, B. De Lotto, M. Polverel, Giancarlo Mantovani, T. Del Prete, R. Moning, M. A. Parker, M. Moniez, L. DiLella, Vincenzo Cavasinni, Bruno Mansoulie, Paolo Bagnaia, P. Darriulat, O. Kofoedo. Kofoed-Hansen, F. Pastore, Michele Livan, H. Hänni, Valerio Vercesi, K. Jacobs, R. Engelmann, Peter Jenni, J. Schacher, F. Stocker, D. Froidevaux, K. Borer, V. Ruhlmann, A. F. Rothenberg, A. Roussarie, K. Bernlöhr, J. P. Repellin, B. Madsen, O. Gildemeister, J. M. Gaillard, H. Plothow-Besch, and J. Dines-Hansen

Subjects
Nuclear physics, Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Cross section (physics), Particle physics, Photon, Large Hadron Collider, law, High Energy Physics::Experiment, Nuclear Experiment, Collider, law.invention
Abstract

Using the UA2 apparatus, the inclusive cross section has been measured for production of high- p T direct photons in pp collisions at s =546 GeV and s =630 GeV . The results are in good agreement with QCD predictions.

Published
1986

53. Measurements of hyperon semileptonic decays at the CERN Super Proton Synchrotron

Author

R. Strub, M. Bourquin, P. Igo-Kemenes, G. Sauvage, Vincent J Smith, B. Merkel, B. J. Saunders, H. Plothow, R. Morand, J. C. Chollet, J. J. Thresher, J. P. Repellin, C. N. P. Gee, P. W. Jeffreys, R.J. Ott, B. Schiby, Daniel Froidevaux, A. R. Fyfe, J. M. Gaillard, H. W. Siebert, W. M. Gibson, R.J. Gray, Y. Chatelus, R. M. Brown, K. P. Streit, and A. Degré

Subjects
Physics, Particle physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), Proton, Physics::Instrumentation and Detectors, Nuclear Theory, Hyperon, Scintillator, Super Proton Synchrotron, Charged particle, Transition radiation, Physics::Accelerator Physics, High Energy Physics::Experiment, Neutrino, Nuclear Experiment, Engineering (miscellaneous)
Abstract

The charged hyperon beam at the CERN Super Proton Synchrotron (SPS) has been used to collect data on semileptonic decays of Σ−, Ξ−, andΛ. A magnetic channel selected 100 GeV/c negatively charged particles produced in the forward direction by interaction of a 210 GeV/c proton beam on a BeO target. The Σ− and Ξ− hyperons were concurrently identified in a DISC Cerenkov counter, and their decay products were analysed by a magnetic spectrometer. Electron-hadron discrimination was achieved by the combined use of lead glass and lead/scintillator counters, transition radiation detectors, and a Cerenkov counter.

Published
1983

54. The ratio …gA/gV… in the decay

Author

I. Videau, R. Vanderhaghien, N. Phinney-Stanko, H. Videau, J. P. Repellin, B. Merkel, J. Badier, R. Meunier, J. C. Cholett, J. Lefrançois, R. W. Bland, A. Romana, D. Décamp, Jean-Marc Gaillard, and G. Sauvage

Subjects
Physics, Nuclear and High Energy Physics, Nuclear magnetic resonance, Magnitude (mathematics), Atomic physics, Sample (graphics)
Abstract

The magnitude of ratio between the axial and vector form factors in the decay Σ − → ne − ν e is measured to be … g A / g V … = 0.17 −0.09 +0.07 from a sample of 519 events with 1.6% background. This result is compared to other experimental values.

Published
1977

55. Performance of a lead-glass electromagnetic shower detector at fermilab

Author

M.H. Bourquin, J.R. Sauer, J.A. Appel, H.P. Paar, D.C. Hom, J.M. Weiss, Leon M. Lederman, H.D. Snyder, T. Yamanouchi, I. Gaines, B.C. Brown, D.H. Saxon, C. N. Brown, J. M. Gaillard, J.K. Yoh, and J. P. Repellin

Subjects
Physics, Range (particle radiation), Spectrometer, Detector, Hadron, General Medicine, Nuclear physics, Lead glass, visual_art, Calibration, visual_art.visual_art_medium, Cathode ray, High Energy Physics::Experiment, Fermilab, Nuclear Experiment
Abstract

The performance of a lead-glass spectrometer system with high resolution and superior hadron rejection is described. We present results on calibration, energy resolution and stability. The use of the system in triggering and in the analysis of an experiment measuring electrons in the energy range 15 to 100 GeV at Fermilab are also described.

Published
1975

56. Observation of Direct Production of Leptons inp-Be Collisions at 300 GeV

Author

D. C. Hom, J. K. Yoh, B. C. Brown, Leon M. Lederman, J. M. Gaillard, H. D. Snyder, J. M. Weiss, I. Gaines, T. Yamanouchi, D. H. Saxon, J.A. Appel, J. P. Repellin, H. P. Paar, and M. H. Bourquin

Subjects
Physics, Particle physics, Muon, Meson, General Physics and Astronomy, Charge (physics), Elementary particle, Fermion, Electron, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment, Lepton
Abstract

Direct production of electrons and muons is observed in 300-GeV $p$-Be collisions. The yields are much higher than predicted from current models. Data are consistent with charge symmetry and universality.

Published
1974

57. Heavy-Particle Production in 300-GeV/cProton/Tungsten Collisions

Author

I. Gaines, B.C. Brown, J. M. Gaillard, J.K. Yoh, D.H. Saxon, Leon M. Lederman, M. Bourquin, J. A. Appel, J. P. Repellin, and H.P. Paar

Subjects
Nuclear physics, Physics, Proton, chemistry, General Physics and Astronomy, chemistry.chemical_element, Heavy particle, Tungsten, Atomic physics
Published
1974

58. Search forϕMesons Produced at Highptinp-Be Collisions at 300 GeV

Author

J. M. Gaillard, J.M. Weiss, C. N. Brown, D.C. Hom, H.D. Snyder, J. A. Appel, H.P. Paar, J. P. Repellin, M. Bourquin, J.R. Sauer, T. Yamanouchi, J. Yoh, Leon M. Lederman, I. Gaines, and B.C. Brown

Subjects
Nuclear physics, Physics, Transverse plane, Meson, chemistry, Mass spectrum, General Physics and Astronomy, chemistry.chemical_element, Beryllium
Published
1975

59. Measurements of hyperon semileptonic decays at the CERN Super Proton Synchrotron

Author

G. Sauvage, J.C. Chollet, J. J. Thresher, R. Morand, K. P. Streit, P. Igo-Kemenes, J. P. Repellin, M. Bourquin, A. Degré, R.J. Ott, P. W. Jeffreys, B. Merkel, Vincent J Smith, Daniel Froidevaux, A. R. Fyfe, W. M. Gibson, R.J. Gray, Y. Chatelus, Robert M Brown, H. W. Siebert, R. Strub, H. Plothow, J. M. Gaillard, B. J. Saunders, B. Schiby, and C. N. P. Gee

Subjects
Physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), Proton, Branching fraction, Hyperon, Dalitz plot, Super Proton Synchrotron, Baryon, Nuclear physics, High Energy Physics::Experiment, Neutrino, Nuclear Experiment, Engineering (miscellaneous)
Abstract

The charged hyperon beam at the CERN Super Proton Synchrotron (SPS) has been used to collect data on semileptonic decays ofΣ−,Ξ− andΛ. A magnetic channel selects 100 GeV/c negatively charged particles produced in the forward direction by interaction of the 200 GeV/c SPS proton beam on a BeO target. TheΣ− andΞ− hyperons are concurrently identified in a DISC Cerenkov counter, and their decay products are analysed by a magnetic spectrometer. Electron-hadron discrimination is achieved by the combined use of lead-glass and lead/scintillator counters, transition radiation detectors, and a Cerenkov counter. In this article we report results on the\(\Sigma ^ -\to \Lambda e^ -\bar v\) decay mode. Measurements of the Λ polarization and of the centre-of-mass distributions (baryon kinetic energy, electron-neutrino correlation, and Dalitz plot distributions) yield the vector to axialvector form factor ratiof1/g1=+0.034±0.080, in agreement with the value expected from the conserved vector current hypothesis (f1/g1=0). TheΣ−→Λe−v→ branching ratio measurement gives a value of (5.41±0.30)×10−5. The effects of radiative corrections are not included in these results. They are discussed in the text. Results on the otherΞ−,Σ−, andΛ semileptonic decays are reported in separate articles.

Published
1982

60. Measurements of hyperon semileptonic decays at the CERN Super Proton Synchrotron

Author

M. Bourquin, R. M. Brown, Y. Chatelus, J. C. Chollet, A. Degré, D. Froidevaux, A. R. Fyfe, J. -M. Gaillard, C. N. P. Gee, W. M. Gibson, R. J. Gray, P. Igo-Kemenes, P. W. Jeffreys, B. Merkel, R. Morand, R. J. Ott, H. Plothow, J. -P. Repellin, B. J. Saunders, G. Sauvage, B. Schiby, H. W. Siebert, V. J. Smith, K. -P. Streit, R. Strub, and J. J. Thresher

Subjects
Physics and Astronomy (miscellaneous), Engineering (miscellaneous)
Published
1983

61. Measurement ofW ± andZ 0 properties at the CERN $$\bar pp$$ p collider

Author

M. Wunsch, John H. L. Hansen, P. Darriulat, M. Polverel, C. Conta, O. Gildemeister, G. Sauvage, Lydia Iconomidou-Fayard, R. Moning, M. Moniez, Roberto Battiston, P. Cenci, G. Parrour, M. Borghini, Claus Gössling, H. Hänni, H. Plothow-Besch, Melody A. Swartz, O. Kofoed-Hansen, K. Borer, M. Pepe, T. Himel, J. C. Chollet, R. Engelmann, J. Schacher, F. Stocker, K. Tittel, L. Di Lella, S. Loucatos, B. De Lotto, A. Roussarie, A. F. Rothenberg, K. Bernlöhr, A. Codino, Michele Livan, J. Dines-Hansen, R. Mollerud, Vincenzo Cavasinni, M. Valdata-Nappi, W. Y. Tsang, Paolo Bagnaia, Giancarlo Mantovani, Louis Fayard, V. G. Goggi, Giovanni Carboni, E. E. Kluge, Allan G Clark, M. Schlötelburg, P. Mani, J. Teiger, M. A. Parker, V. Ruhlmann, J. A. Appel, Peter Jenni, A. R. Weidberg, K. Meier, N. Harnew, Livio Mapelli, J. P. Repellin, F. Pastore, Valerio Vercesi, C. Onions, D. Froidevaux, Bruno Mansoulie, M. Banner, S.N. Tovey, H. Zaccone, Kevin Einsweiler, T. Del Prete, B. Hahn, B. Merkel, B. Madsen, J. M. Gaillard, M. Morganti, A. Putzer, Marco Fraternali, Peter Hansen, B.S. Nilsson, Eric Lancon, and K. Jakobs

Subjects
Physics, Quantum chromodynamics, Particle physics, Luminosity (scattering theory), Large Hadron Collider, Physics and Astronomy (miscellaneous), Electroweak interaction, Weinberg angle, Elementary particle, law.invention, Standard Model, Nuclear physics, law, High Energy Physics::Experiment, Nuclear Experiment, Collider, Engineering (miscellaneous)
Abstract

A study ofW± andZ0 properties has been performed using the UA2 detector at the\(\bar pp\) collider. The data correspond to a total integrated luminosity of 142 nb−1 at\(\sqrt s \)=546 GeV, and of 310 nb−1 at\(\sqrt s \)=630 GeV. The experimental results are compared with the predictions of the Standard Model of the unified electroweak theory.

Published
1986

62. Inclusive π0 production at the CERN p-p̄ collider

Author

John H. L. Hansen, H. Zaccone, B.S. Nilsson, O. Kofoed-Hansen, F. Stocker, V. Hungerbühler, R. Mollerud, A. F. Rothenberg, T. Himel, S. Loucatos, C. Conta, C. Onions, Louis Fayard, Ph. Bloch, Peter Jenni, G.C. Mantovani, J. M. Gaillard, J. Dines-Hansen, L. Di Lella, P. H. Hansen, Allan G Clark, Michele Livan, B. Merkel, V. G. Goggi, J. P. Repellin, A. Roussarie, J. C. Chollet, Marco Fraternali, W. Zeller, Daniel Froidevaux, Fr. Pastore, M. Banner, P. A. Dorsaz, G. Parrour, Valerio Vercesi, H. Hänni, M. Borghini, H. Grote, Livio Mapelli, K. Borer, J. Teiger, J. Schacher, J. Ringel, B. Hahn, F. Bonaudi, H. Plothow-Besch, O. Gildemeister, B. Madsen, G. Sauvage, Bruno Mansoulie, J. L. Siegrist, and P. Darriulat

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Muon, Meson, Hadron, Elementary particle, Nuclear physics, Pion, High Energy Physics::Experiment, Nuclear Experiment, Lepton, Boson
Abstract

Inclusive π 0 production has been measured at the CERN pp collider, s =540 GeV , for 90° production angle and in a range of transverse momenta between 1.5 and 4.5 GeV/ c . The invariant production cross section is larger than that measured at s = 53 GeV for p-p collisions. The production of μ mesons aand of direct photons is also investigated.

Published
1982

63. Particle and antiparticle production by 200 GeV/c protons in the charged hyperon beam at the CERN SPS

Author

M. Croissiaux, R. M. Brown, R. Morand, M. Ferro-Luzzi, K. P. Streit, J. J. Thresher, M. Bourquin, P. Igo-Kemens, B.J. Saunders, A. Degré, P. W. Jeffreys, J. P. Repellin, B. Schiby, Vincent J Smith, W. M. Gibson, R. Strub, J.-M. Gaillard, R.J. Gray, Y. Chatelus, R.J. Ott, Daniel Froidevaux, C. N. P. Gee, H. W. Siebert, G. Sauvage, J. Trischuk, A. R. Fyfe, B. Merkel, J. C. Chollet, and H. Plothow

Subjects
Nuclear physics, Physics, Momentum, Nuclear and High Energy Physics, Antiparticle, Range (particle radiation), Large Hadron Collider, Proton, Hyperon, Particle, High Energy Physics::Experiment, Nuclear Experiment, Beam (structure)
Abstract

A charge hyperon beam has been brought into operation at the CERN SPS. Particles are identified by a DISC Cerenkov counter, and decay products are analysed by a magnetic spectrometer. Cross sections for the inclusive production of π + , K + , p , Σ + , Σ − , ζ − , d, and π − , K − , p , Σ + , Σ − , ζ − , ω − , d in the forward direction have been measured at laboratory momenta between 70 and 130 GeV/ c . This range of momenta corresponds to 0.35 ⩽ x ⩽ 0.66 for an incident proton momentum of 200 GeV/ c . Antihyperon ( Σ − , ζ − , Σ + ) and Σ + and ω − fluxes have been measured for the first time in a hyperon beam. Scaling behaviour is observed when the data are compared with the results from other experiments. The inclusive particle production cross sections have a (1 − x ) n dependence, where n is characteristics of the particle. A search has been made for new particles in the mass range 2–10 GeV/ c 2 . No evidence is found for such particles.

Published
1979

64. Transition and synchrotron radiation produced by electrons and particle discrimination

Author

Ph. Jean, B. Merkel, G. Sauvage, J.M. Gaillard, M. Dialinas, J.C. Chollet, J.-P. Repellin, Maurice Bourquin, A. Hrisoho, Laboratoire de l'Accélérateur Linéaire (LAL), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Hadron, Synchrotron radiation, chemistry.chemical_element, General Medicine, Electron, 01 natural sciences, law.invention, Xenon, chemistry, Transition radiation, law, 0103 physical sciences, Particle, Lithium, Atomic physics, 010306 general physics, Radiator
Abstract

Transition radiation from a radiator of 650 lithium foils has been studied in a MWPC filled with a xenon-Co 2 mixture for two experimental configurations. With the chamber immediately behind the radiator, particle discriminations comparable to those reported in the literature (90% efficiency for electrons, 10% for hadrons) have been observed. With magnetic bending between the radiator and the xenon chamber typical efficiencies of 87% for electrons and less than 0.4% for hadrons have been measured. The discrimination obtained is at least a factor 20 better than for the more conventional configuration. In the latter case, synchrotron radiation has also been observed.

Published
1976

65. Measurement of Ω− decay properties in the CERN SPS hyperon beam

Author

R. Strub, J.C. Chollet, M. Jung, M. Bourquin, R. Morand, Hartmute Plothow-Besch, J.P. Gerber, J.-M. Gaillard, Vincent J Smith, P.W. Jeffreys, B. Schiby, W.M. Gibson, J.-L. Riester, G. Sauvage, Daniel Froidevaux, R.M. Brown, B.J. Saunders, H. W. Siebert, K. P. Streit, P. Igo-Kemenes, B. Merkel, C.N.P. Gee, J. J. Thresher, J.-P. Repellin, A. Degré, and S. N. Tovey

Subjects
Physics, Nuclear and High Energy Physics, Large Hadron Collider, Analytical chemistry, Hyperon, Atomic physics
Abstract

In an experiment in the CERN SPS charged hyperon beam, a sample of 16 000Ω− decays was collected at an Ω− momentum of 131 GeV/c the Ω− lifetime, the branching ratios and decay asymmetry parameters for the main decay modes were measured, giving: τ Ω − =(0.823±0.015)×10 −10 s , Γ(Ω − →Λ K − ) Γ(Ω − -→ all ) =0.675±0.008 , α(Ω − →Λ K − )= −0.025±0.028, Γ(Ω − →Ξ 0 π − ) Γ(Ω − → all ) = 0.236±0.008 , α(Ω − →Ξ 0 π − )=0.09±0.14, Γ(Ω − →Ξ − π 0 ) Γ(Ω − → all ) =0.089±0.005 , α(Ω − →Ξ − π 0 )=0.05±0.21. For the rare decay modes, the following results for the branching ratios were obtained: if Γ(Ω − →Ξ 0 e − ν ) Γ(Ω − → all ) =(0.56±0.28)×10 −2 , if Γ(Ω − →Ξ − π + π − ) (Γ(Ω→ all ) =(3.7 −1.1 +3.6 )×10 −4 , Γ(Ω − →Ξ − γ) (Γ(ω − → all ) −3 at the 90% confidence level, Γ(Ω − →Λπ − ) (Γ(Ω − → all ) −4 at the 90% confidence level . A sample of 32 000 Ξ− decays collected under the same experimental conditions gave a new measurement of the Ξ− lifetime: τ Ξ − =(1.652±0.051)×10 −10 s . Combining the measurements of the present experiment with those obtained in a previous experiment in the SPS hyperon beam gives: if τ Ω − =(0.823±0.013)×10 −10 s , Γ(Ω − →Λ K − ) Γ(Ω − → all =0.678±0.007 , Γ(Ω − →Ξ 0 π − ) Γ(Ω − → all ) =0.236±0.007 , Γ(Ω − →Ξ − π 0 ) Γ(Ω − → all =0.086±0.004 , Γ(Ω − →Ξ − π + π − ) Γ(Ω − → all =(4.3 −1.3 +3.4 )×10 −4 . The experimental results are compared with theoretical calculations.

Published
1984

66. A study of three-jet events at the CERN $$\bar pp$$ collider

Author

M. Borghini, V. Ruhlmann, M. Pepe, Roberto Battiston, V. G. Goggi, L. Di Lella, M. Valdata-Nappi, Melody A. Swartz, Lydia Iconomidou-Fayard, Peter Jenni, M. Wunsch, John H. L. Hansen, M. Banner, J. C. Chollet, R. Engelmann, J. Schacher, Valerio Vercesi, H. Plothow-Besch, C. Conta, M. Polverel, R. Mollerud, K. Borer, B. De Lotto, W. Y. Tsang, K. Bernlöhr, Louis Fayard, J. Bürger, T. Himel, O. Gildemeister, R. Moning, P. Cenci, P. Darriulat, B. Merkel, F. Stocker, A. Codino, J. Dines-Hansen, A. F. Rothenberg, G. Sauvage, J. A. Appel, K. Jakobs, Eric Lancon, J. P. Repellin, O. Kofoed-Hansen, K. Meier, Giovanni Carboni, Marco Fraternali, Michele Livan, H. Zaccone, B. Hahn, C. Onions, D. Froidevaux, S. Loucatos, H. Hänni, G. Parrour, Peter Hansen, Claus Gössling, F. Pastore, Giancarlo Mantovani, M. A. Parker, Adele Rimoldi, B. Madsen, T. Del Prete, Vincenzo Cavasinni, M. Moniez, Paolo Bagnaia, Allan G Clark, A. R. Weidberg, P. Mani, S.N. Tovey, Kevin Einsweiler, A. Roussarie, N. Harnew, Livio Mapelli, E. E. Kluge, J. M. Gaillard, M. Morganti, Bruno Mansoulie, M. Schlötelburg, and J. Teiger

Subjects
Quantum chromodynamics, Physics, Particle physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), Bar (music), Bremsstrahlung, Jet (particle physics), Measure (mathematics), law.invention, Gluon, Nuclear physics, law, High Energy Physics::Experiment, Collider, Engineering (miscellaneous)
Abstract

The UA2 experiment, running at the CERN SPS\(\bar pp\) Collider, has performed a study of events containing three hard jets in the final state. The angular distributions of the three jets show evidence for gluon bremsstrahlung, in good agreement with a QCD model to leading order in the strong coupling constant αs. The yield of three-jet events relative to that of two-jet events provides a measure of the strong coupling constant: ;3K3/K2=0.23±0.01±0.04, whereK2 andK3 represent the contributions arising from higher order corrections in α3 to the two- and three-jet exclusive cross-sections. A detailed discussion of the systematic and theoretical uncertainties is given.

Published
1986

67. The Σ−p and Σ−d total cross sections at 19 GeV

Author

G. Sauvage, Thomas J. Devlin, J. Badier, J. M. Gaillard, R. W. Bland, R. Meunier, B. Merkel, R. Vanderhagen, J. Lefrançois, J. P. Repellin, J.C. Chollet, A. Romana, and D. Décamp

Subjects
Physics, Nuclear physics, Quark, Nuclear and High Energy Physics, Neutron cross section, Hyperon, Neutron, Sum rule in quantum mechanics
Abstract

The total cross sections of 18.7 GeV Σ − hyperons on protons and deutrons have been measured to be 34.0 ± 1.1 mb and 61.3 + 1.4 mb, respectively. The derived Σ − -neutron cross section is 30.0 ± 1.2 mb.

Published
1972

68. Negative hyperon production at high energy

Author

J. Lefrançois, J. P. Repellin, J. Badier, R. W. Bland, R. Meunier, Thomas J. Devlin, B. Merkel, Jean-Marc Gaillard, G. Sauvage, R. Vanderhaghen, and J.C. Chollet

Subjects
Physics, Nuclear reaction, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Proton, Hyperon, chemistry.chemical_element, Tungsten, Nuclear physics, Momentum, chemistry, Antiproton, Beam (structure)
Abstract

With a negative hyperon beam which we have constructed at the CERN PS we have measured the production by 24 GeV/c proton of K−, p , Σ−, and −, with respect to π− production. Measurements were made on a tungsten target under the following conditions: 1. at a fixed angle of 10 mrad for momenta between 13 and 20 GeV/c, 2. at a fixed momentum of 17.2 GeV/c for angles between 10 and 40 mrad. Production was studied on three targets (B4C, Al, W) at 17.2 GeV/c and 10 mrad. Photographs of hyperon decays have also been taken in a prototype streamer chamber.

Published
1972

69. The phase of ηoo and the invariances CPT and T

Author

J.-M. Gaillard, J.-P. Repellin, M.R. Jane, B. Wolff, K.R. Schubert, and T. J. Ratcliffe

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Amplitude, Pion, Invariance principle, Quantum mechanics, Parity (physics)
Abstract

The decay amplitude ϵ o = 2 3 η +− + 1 3η oo is decomposed into a CPT-conserving, T-violating part ϵ, and a T-conserving, CPT-violating part δ. Using the measurement of the phase of ηoo together with other results on Ko decays we obtain: Reϵ = (1.68 ± 0.30) × 10−3, IM ϵ = (1.45 ± 0.30) × 10−3. Re δ = (0.07 ±) × 10 −3 , Im δ = (−0.30 ± 0.45) × 10 −3 .

Published
1970

70. Further results on the interference between the πoπo decay of KLo and KSo

Author

M.R. Jane, J.-M. Gaillard, K.R. Schubert, J.C. Chollet, J. P. Repellin, and B. Wolff

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Amplitude, chemistry, chemistry.chemical_element, Atomic physics, Interference (wave propagation), Copper
Abstract

The experiment of Chollet et al. has been continued with a similar set up. The analysis of these new data leads to 56 free decay events KLo→πoπo and 1481 interference events KS, Lo, → πoπo behind a 20 cm thick copper regenerator. The results are ϕoo = 38o ± 25o and |ηoo|/(|f−f|/k) = (1.13 ± 0.12) × 10−3 where |f−f|/k is the regeneration amplitude for copper at 2 GeV/c in fm2.

Published
1971

71. Coherent photoproduction of π0 on helium

Author

J. Lefrançois, P. Lehmann, and J. P. Repellin

Subjects
Physics, Nuclear reaction, Nuclear physics, Helium-4, Photon, Proton, chemistry, Momentum transfer, Bremsstrahlung, chemistry.chemical_element, Atomic physics, Spectroscopy, Helium
Abstract

The coherent photoproduction cross-section of π0 on helium has been measured for five values of the squared momentum transfer from 3 to 6.7 fm−2 and for gamma-ray energy from 260 to 800 MeV. The results are compared with simple impulse-approximation calculation limited to the contribution of the first resonanceP3/2 3/2 which appears clearly but is strongly depressed due to rescattering effects. A good agreement with data is obtained between 450 and 650 gamma-ray energy by using a nuclear distribution 6% more concentrated than the proton distribution in helium. This indicates that there is no evidence of the contribution of theP1/2 1/2 orD1/2 a/2 waves.

Published
1970

72. Measurement of the KL0 → 2γ branching ratio and search for KS0 → 2γ decays

Author

J.C. Chollet, K.R. Schubert, M.R. Jane, J.-M. Gaillard, J. P. Repellin, and B. Wolff

Subjects
Physics, Nuclear and High Energy Physics, Meson, Branching fraction, Atomic physics
Abstract

Using an optical spark chamber set-up, we have measured the two photon decay rate of neutral K mesons behind a regenerator. KL0 → 2γ decays are normalized to KS0 → 2π0 events, so the result depends on the K0 regeneration in copper at 2 GeV/c and has a value of Γ( K L 0 → 2γ) Γ( K L 0 → all ) = (5.0 ± 1.0) × 10 −4 [22 mb /(|ƒ− ƒ |/k)] 2 . KS0 → 2γ events are not observed, and from the normalization to KS0 → 2γ0 we get Γ( K S 0 → 2γ) Γ( K S 0 → all ) −3 with 90% conf

Published
1971

73. Inclusive particle production in the transverse momentum range between 0.25 and 40 GeV/c at the CERN Sp$\overline{p}$S collider

Author

Eric Lancon, V. Hungerbühler, F. Bonaudi, J. Dines Hansen, K. Borer, B. Madsen, H. Plothow-Besch, C. Onions, D. Froidevaux, Peter Jenni, P. A. Dorsaz, B. Hahn, Michele Livan, Marco Fraternali, J. C. Chollet, W. Zeller, Peter Hansen, L. Di Lella, Valerio Vercesi, Livio Mapelli, J. M. Gaillard, H. Hänni, Allan G Clark, V. G. Goggi, P. Mani, H. Zaccone, F. Stocker, A. F. Rothenberg, M. Banner, Bruno Mansoulie, J. Schacher, J. Teiger, F. Pastore, O. Gildemeister, O. Kofoed-Hansen, J. L. Siegrist, T. Himel, A. Roussarie, S. Loucatos, Ph. Bloch, Giancarlo Mantovani, John H. L. Hansen, Adele Rimoldi, C. Conta, B. Merkel, R. Mollerud, Louis Fayard, A. R. Weidberg, G. Sauvage, M. Polverel, G. Parrour, P. Darriulat, M. Borghini, and J. P. Repellin

Subjects
Physics, Particle physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), Meson, Branching fraction, Hadron, Elementary particle, Charged particle, law.invention, Nuclear physics, Pion, law, High Energy Physics::Experiment, Nuclear Experiment, Collider, Engineering (miscellaneous), Particle Physics - Experiment
Abstract

Inclusive particle production cross-sections have been measured at the $$Sp\bar pS$$ collider using the UA2 detector in various ranges of transverse momentum (P T ) and pseudo-rapidity (η). Cross-section measurements are presented forπ 0 production (P T ≦15 GeV/c, |η|≦0.85 andP T ≦40 GeV/c, 1.0≦|η|≦1.8), for η meson production (3≦P T ≦6 GeV/c, |η|≦0.85) and for charged particle production (P T ≦10 GeV/c, 1.0≦|η|≦1.8). Results are compared with the predictions of QCD calculations.

Published
1985

74. Experiments with the Cern SPS hyperon beam

Author

J.-P. Repellin, M. Bourquin, Starita, Sabine, Laboratoire de l'Accélérateur Linéaire (LAL), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Scattering cross-section, Particle physics, High energy, Large Hadron Collider, Proton, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], 010308 nuclear & particles physics, Nuclear Theory, Form factor (quantum field theory), Hyperon, General Physics and Astronomy, 01 natural sciences, Nuclear physics, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Physics::Accelerator Physics, High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Beam (structure)
Abstract

High energy charged hyperons produced in proton collisions at large accelerators have a lifetime long enough to be channelled into beams of particles of appreciable intensity. This has opened up a new domain of research in experimental high energy physics. This article reviews recent works at the CERN SPS using a dedicated charged hyperon beam facility.

Published
1984

75. SEARCH FOR DECAYS OF THE W+/-BOSONS AND Z-BOSONS INTO QUARK ANTIQUARK PAIRS

Author

Marco Fraternali, M. Moniez, Roberto Battiston, M. Morganti, H. Hänni, Eric Lancon, K. Borer, J. Dines-Hansen, V. Ruhlmann, Christophe Corona, Melody A. Swartz, Claus Gössling, N. Harnew, Livio Mapelli, R. Mollerud, P. Lariccia, C. N. Booth, D. Froidevaux, Louis Fayard, L. DiLella, J. Teiger, C. Onions, Peter Jenni, E. E. Kluge, E. Iacopini, B. Merkel, K. Jakobs, R. Moning, B. Hahn, Chariclia Petridou, E. Hugentobler, V. G. Goggi, H. Zaccone, Steinar Stapnes, M. Valdata-Nappi, P. Cenci, Allan G Clark, Vincenzo Cavasinni, J. P. Repellin, G. Sauvage, Paolo Bagnaia, J. M. Gaillard, Bruno Mansoulie, H. Plothow-Besch, P. H. Hansen, M. Wunsch, F. Costantini, M. Banner, W.Y. Tsang, G. Parrour, K. Hara, Giovanni Carboni, John H. L. Hansen, Lydia Iconomidou-Fayard, M. Polverel, C. Conta, M. Pepe, J. Schacher, K. Bernlöhr, S. Lami, Roberto Ferrari, O. Kofoed-Hansen, B. Madsen, F. Pastore, M. Borghini, S. Loucatos, O. Gildemeister, R. Ansari, J. C. Chollet, Giancarlo Mantovani, Michele Livan, B. De Lotto, M. A. Parker, Adele Rimoldi, F. Stocker, P. Darriulat, A. Roussarie, Valerio Vercesi, L. Rasmussen, T. Del Prete, A. R. Weidberg, Kevin Einsweiler, and K. Meier

Subjects
Quark, Physics, Nuclear and High Energy Physics, Particle physics, Hadron, Elementary particle, Nuclear physics, Particle decay, W and Z bosons, Mass spectrum, High Energy Physics::Experiment, Invariant mass, Particle Physics - Experiment, Boson
Abstract

The invariant mass distribution of jet pairs observed in the UA2 central calorimeter is examined in the search for an excess of events in the region of the W ± and Z bosons, which would reveal their decays into quark-antiquark pairs. We give a detailed account of the methods of analysis used to optimize the mass resolution achieving ≅±10%. A structure is observed at the level of ≅ 3 standard deviations in the mass region of W ± and Z with shape and position consistent with expectation from their qqdecays. It contains 632 ± 190 events, 1.4 standard deviations above the standard model prediction of 340 ± 80 events.

Published
1987

76. Charged baryon and antibaryon production in the fragmentation region by 240 GeV protons

Author

P. W. Jeffreys, B. J. Saunders, J. P. Repellin, Vincent J Smith, Daniel Froidevaux, P. Igo-Kemenes, R. Strub, K. P. Streit, M. Bourquin, W. M. Gibson, J. J. Thresher, R. M. Brown, Y. Chatelus, J. M. Gaillard, R. Morand, H. W. Siebert, H. Plothow, J. C. Chollet, B. Merkel, A. R. Fyfe, A. Degré, S. N. Tovey, G. Sauvage, C. N. P. Gee, B. Schiby, 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 Heyd, Yvette

Subjects
Physics, Baryon, Nuclear physics, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Particle physics, Physics and Astronomy (miscellaneous), Proton, Fragmentation (mass spectrometry), [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Yield ratio, Strangeness, Engineering (miscellaneous), Particle Physics - Experiment
Abstract

Measurements of the production inp-BeO collisions of charged baryons and antibaryons with strangeness between −3 and +3 at $$\sqrt s = 21.2GeV$$ x=0.48, andp T =600MeV/c are reported. The experimental results can be interpreted within the framework of a simple proton fragmentation-recombination model.

Published
1980

77. Measurement of the standard model parameters from a study of W and Z bosons

Author

Giovanni Carboni, P. Lariccia, B. Lisowski, John H. L. Hansen, Lydia Iconomidou-Fayard, C. Conta, F. Pastore, J. M. Gaillard, H. Plothow-Besch, Allan G Clark, A. Roussarie, V. G. Goggi, Valerio Vercesi, K. Borer, P. H. Hansen, W.Y. Tsang, V. Ruhlmann, M. Moniez, K. Hara, Marco Fraternali, C. Onions, F. Stocker, M. Morganti, P. Darriulat, J. Dines-Hansen, G. Sauvage, T. Del Prete, Roberto Battiston, H. Zaccone, E. Iacopini, B. Hahn, J. Teiger, Chariclia Petridou, B. Madsen, G. Parrour, T. Pal, Vincenzo Cavasinni, Paolo Bagnaia, Melody A. Swartz, N. Harnew, Livio Mapelli, D. Froidevaux, B. De Lotto, L. Rasmussen, Claus Gössling, F. Costantini, E. E. Kluge, L. Di Lella, Michele Livan, O. Gildemeister, R. Moning, H. Hänni, Bruno Mansoulie, B. Merkel, M. Banner, P. Cenci, O. Kofoed-Hansen, A. R. Weidberg, S. Loucatos, R. Mollerud, S.N. Tovey, Louis Fayard, Kevin Einsweiler, Peter Jenni, Giancarlo Mantovani, M. A. Parker, M. Pepe, Roberto Ferrari, J. C. Chollet, Eric Lancon, M. Wunsch, K. Jakobs, M. Polverel, J. A. Zakrzewski, C. N. Booth, J. P. Repellin, M. Borghini, R. Ansari, J. Schacher, K. Bernlöhr, E. Hugentobler, M. Valdata-Nappi, K. Meier, Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and UA2

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Luminosity (scattering theory), 010308 nuclear & particles physics, Electroweak interaction, Weinberg angle, 7. Clean energy, 01 natural sciences, law.invention, Standard Model, Nuclear physics, law, 0103 physical sciences, W′ and Z′ bosons, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Neutrino, Nuclear Experiment, 010306 general physics, Collider, Particle Physics - Experiment
Abstract

A study has been made of the decays W → ev and Z → e + e − , using the UA2 detector at the CERN pp Collider. The data correspond to an integrated luminosity of 142 nb −1 at a centre-of-mass collision energy √ s =546 GeV, and 768 nb −1 at √ s =630 GeV. Measurements of the standard model parameters from samples of 251 W decay and 39 Z decay candidates are compared with expectations of the standard electroweak model.

Published
1987

78. EVIDENCE FOR Z0-]E+E- AT THE CERN P-P COLLIDER

Author

H. Zaccone, F. Bonaudi, B.S. Nilsson, G. Sauvage, O. Kofoed-Hansen, B. Merkel, F. Stocker, A. F. Rothenberg, J. C. Chollet, B. Madsen, J. Dines-Hansen, A. R. Weidberg, G. Stimpfl, P. A. Dorsaz, J. M. Gaillard, H. Plothow-Besch, Valerio Vercesi, V. Hungerbühler, Michele Livan, Marco Fraternali, W. Zeller, T. Himel, G. Fumagalli, J. Schacher, B. Hahn, Allan G Clark, P. Mani, Livio Mapelli, S. Loucatos, H.M. Steiner, Ph. Bloch, Giancarlo Mantovani, Adele Rimoldi, O. Gildemeister, Peter Jenni, Eric Lancon, L. Di Lella, K. Borer, J. Teiger, P. Darriulat, G. Parrour, H. Hänni, Paolo Bagnaia, C. Onions, Bruno Mansoulie, M. Borghini, J. L. Siegrist, A. Roussarie, Roberto Battiston, H. Grote, M. Mermikides, M. Banner, M. Polverel, J. A. Zakrzewski, J. P. Repellin, R. Mollerud, Louis Fayard, Daniel Froidevaux, V. G. Goggi, John H. L. Hansen, C. Conta, P. H. Hansen, and F. Pastore

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Electron pair, Large Hadron Collider, Electroweak interaction, Weinberg angle, Electron, law.invention, Vector boson, Nuclear physics, law, High Energy Physics::Experiment, Collider, Boson
Abstract

From a search for electron pairs produced in p p collisions at s = 550 GeV we report the observation of eight events which we interpret as resulting from the process p +p→Z 0 + anything, followed by the decay Z0→e++e− or Z0→e++e−+γ, where Z0 is the neutral Intermediate Vector Boson postulated by the unified electroweak theory. We use four of these events to measure the Z0 mass M Z = 91.9 ± 1.3 ± 1.4 (systematic) GeV /c 2 .

Published
1983

79. MEASUREMENT OF VERY LARGE TRANSVERSE-MOMENTUM JET PRODUCTION AT THE CERN P-BAR-P COLLIDER

Author

F. Stocker, L. Di Lella, A. Roussarie, A. F. Rothenberg, O. Kofoed-Hansen, G. Stimpfl, Claus Gössling, Eric Lancon, M. Borghini, Livio Mapelli, S. Loucatos, Michele Livan, H. Plothow-Besch, Marco Fraternali, C. Onions, D. Froidevaux, G. Sauvage, B. Hahn, W. Zeller, Peter Hansen, R. Engelmann, Ph. Bloch, A. R. Weidberg, Giancarlo Mantovani, J. A. Zakrzewski, Bruno Mansoulie, B. Madsen, J. Teiger, H. Zaccone, J. C. Chollet, J. Dines-Hansen, Allan G Clark, P. Mani, O. Gildemeister, M. J. Shochet, Adele Rimoldi, M. Banner, John H. L. Hansen, G. Parrour, J. L. Siegrist, J. Schcher, Roberto Battiston, J. P. Repellin, C. Conta, H. Hänni, Melody A. Swartz, M. Polverel, R. Mollerud, K. Borer, B. Merkel, F. Pastore, P. Darriulat, Louis Fayard, Valerio Vercesi, V. G. Goggi, J. Bürger, J. M. Gaillard, Peter Jenni, Paolo Bagnaia, and T. Himel

Subjects
Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Range (particle radiation), Particle physics, Large Hadron Collider, Calorimeter (particle physics), Astrophysics::High Energy Astrophysical Phenomena, Hadron, Jet (particle physics), law.invention, Nuclear physics, law, High Energy Physics::Experiment, Invariant mass, Nuclear Experiment, Collider
Abstract

The production of very large transverse momentum hadron jets has been measured in the UA2 experiment at the CERN p p Collider for s = 540 GeV using a highly segmented calorimeter. The range of previously available cross sections for inclusive jet production is extended to pT = 150 GeV and the two-jet invariant mass distribution to mjj = 280 GeV with the largely increased data sample collected during the 1983 running period. The results are compared with the predictions of QCD models.

Published
1984

80. SEARCH FOR EXOTIC PROCESSES AT THE CERN PPBAR COLLIDER

Author

G. Sauvage, Roberto Ferrari, Marco Fraternali, J. C. Chollet, B. Hahn, Chariclia Petridou, M. Morganti, G. Parrour, P. Lariccia, Allan G Clark, Steinar Stapnes, B. De Lotto, B. Madsen, Peter Jenni, P. Bagnala, J. M. Gaillard, H. Plothow-Besch, B. Merkel, O. Gildemeister, V. G. Goggi, R. Moning, M. Wunsch, E. Iacopini, Bruno Mansoulie, M. Banner, M. Moniez, P. Darriulat, E. Hugentobler, Vincenzo Cavasinni, P. Cenci, O. Kofoed-Hansen, W.Y. Tsang, Roberto Battiston, Michele Livan, M. Valdata-Nappi, K. Hara, S. Loucatos, H. Hänni, M. Polverel, Melody A. Swartz, F. Stocker, John H. L. Hansen, N. Harnew, C. Conta, Livio Mapelli, Lydia Iconomidou-Fayard, Giancarlo Mantovani, J. Schacher, H. Zaccone, J. Dines-Hansen, K. Borer, V. Ruhlmann, D. Froidevaux, Valerio Vercesi, M. A. Parker, A. Roussarie, Eric Lancon, M. Borghini, E. E. Kluge, K. Bernlöhr, F. Costantini, M. Pepe, L. Di Lella, R. Ansari, R. Mollerud, K. Jacobs, C. N. Booth, Claus Gössling, J. P. Repellin, J. Teiger, K. Meier, T. Pal, Giovanni Carboni, Louis Fayard, T. Del Prete, F. Pastore, P. H. Hansen, C. Onions, A. R. Weidberg, Kevin Einsweiler, and L. Rasmussen

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Luminosity (scattering theory), law, Excited state, High Energy Physics::Experiment, Neutral vector, Collider, law.invention, Boson
Abstract

The total UA2 data sample at the CERN pp Collider corresponds to an integrated luminosity of 910 nb −1 . Limits on various hypothetical processes, such as production of excited electrons, additional charged or neutral vector bosons, or supersymmetric particles, are presented from the analysis of this sample.

Published
1987

81. Design and rejection studies for a cylindrical transition radiation detector for the UA2 upgrade

Author

B. Merkel, G. Parrour, M. Moniez, B. De Lotto, Lydia Iconomidou-Fayard, J. P. Repellin, Louis Fayard, Daniel Froidevaux, J. C. Chollet, R. Ansari, Laboratoire de l'Accélérateur Linéaire (LAL), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Starita, Sabine

Subjects
Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, business.industry, Hadron, chemistry.chemical_element, Electron, 7. Clean energy, 01 natural sciences, Transition radiation detector, Optics, Upgrade, chemistry, [PHYS.PHYS.PHYS-INS-DET] Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], 0103 physical sciences, Cluster (physics), Lithium, [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

A study of a compact and cylindrical transition radiation detector is described. A prototype has been built and tested with 40 GeV electrons and hadrons. The measurement have been done using 100 MHz FADC. We have compared different radiators and chamber geometries using various algorithms. The cluster counting and the total integrated charge methods give comparable results. A comparison between radiators of lithium and polypropylene is made.

Published
1986

82. Measurement of W and Z Production Properties at the CERN anti-p p Collider

Author

R. Ansari, P. Bagnaia, M. Banner, R. Battiston, K. Bernlöhr, C. Booth, K. Borer, M. Borghini, G. Carboni, V. Cavasinni, P. Cenci, J.-C. Chollet, A.G. Clark, C. Conta, F. Costantini, P. Darriulat, B. de Lotto, T. del Prete, L. Dilella, J. Dines-Hansen, K. Einsweiler, L. Fayard, R. Ferrari, M. Fraternali, D. Froidevaux, J.-M. Gaillard, O. Gildemeister, V.G. Goggi, C. Gössling, B. Hahn, H. Hänni, J.R. Hansen, P. Hansen, K. Hara, N. Harnew, E. Hugentobler, E. Iacopini, L. Iconomidou-Fayard, K. Jakobs, P. Jenni, E.E. Kluge, O. Kofoed-Hansen, E. Lançon, P. Lariccia, M. Livan, S. Loucatos, B. Madsen, B. Mansoulié, G.C. Mantovani, L. Mapelli, K. Meier, B. Merkel, R. Möllerud, M. Moniez, R. Moning, M. Morganti, C. Onions, T. Pal, M.A. Parker, G. Parrour, F. Pastore, M. Pepe, Ch. Petridou, H. Plothow-Besch, M. Polverel, L. Rasmussen, J.-P. Repellin, A. Roussarie, V. Ruhlmann, G. Sauvage, J. Schacher, F. Stocker, M. Swartz, J. Teiger, K. Tittel, S.N. Tovey, W.Y. Tsang, M. Valdata-Nappi, V. Vercesi, A.R. Weidberg, M. Wunsch, and H. Zaccone

Subjects
Quantum chromodynamics, Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Luminosity (scattering theory), Parton, Jet (particle physics), law.invention, Momentum, Nuclear physics, law, W and Z bosons, High Energy Physics::Experiment, Collider
Abstract

A study has been made of the production characteristics of W and Z bosons produced at the CERN p p Collider. The event sample consists of 251 W→ev decays, and 39 Z→e + e − decays, identified by the UA2 detector, and corresponds to an integrated luminosity of 142 nb −1 at √ s = 546 GeV, and 768 nb −1 at √ s = 630 GeV. Measurements of W and Z production cross sections, of longitudinal and transverse momentum distributions, and of associated jet production, are presented. These measurements are compared with theoretical expectations, which include higher order QCD effects.

Published
1987

83. JET MEASURES AND HADRONIC EVENT SHAPES AT THE CERN anti-p p COLLIDER

Author

Steinar Stapnes, V. G. Goggi, H. Plothow-Besch, V. Ruhlmann, G. Sauvage, M. Moniez, L. DiLella, A. Roussarie, R. Mollerud, K. Meier, Louis Fayard, H. Hänni, Peter Jenni, N. Harnew, Livio Mapelli, G. Parrour, O. Kofoed-Hansen, K. Borer, O. Gildemeister, P. H. Hansen, Lydia Iconomidou-Fayard, Roberto Ferrari, J. C. Chollet, Eric Lancon, S. Loucatos, T. Del Prete, J. Dines-Hansen, Giovanni Carboni, Allan G Clark, M. Pepe, P. Lariccia, E. E. Kluge, B. Madsen, Chariclia Petridou, Giancarlo Mantovani, F. Pastore, J. Schacher, R. Moning, F. Costantini, M. A. Parker, Bruno Mansoulie, F. Stocker, Michele Livan, Adele Rimoldi, M. Banner, K. Bernlöhr, C. Onions, D. Froidevaux, B. Hahn, E. Iacopini, K. Jakobs, Claus Gössling, Vincenzo Cavasinni, Paolo Bagnaia, M. Morganti, L. Rasmussen, B. De Lotto, P. Darriulat, H. Zaccone, J. Teiger, B. Merkel, P. Cenci, Valerio Vercesi, A. R. Weidberg, Kevin Einsweiler, C. N. Booth, J. P. Repellin, Marco Fraternali, M. Borghini, R. Ansari, M. Wunsch, M. Polverel, Roberto Battiston, Melody A. Swartz, J. M. Gaillard, E. Hugentobler, M. Valdata-Nappi, W.Y. Tsang, K. Hara, John H. L. Hansen, and C. Conta

Subjects
Physics, Range (particle radiation), Particle physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), Calorimeter (particle physics), Hadron, Parton, law.invention, Nuclear physics, Transverse plane, law, Phase space, High Energy Physics::Experiment, Nuclear Experiment, Collider, Engineering (miscellaneous), Particle Physics - Experiment
Abstract

We analyze the energy density distribution in harronic final states as a function of their total transverse energy measured in the segmented central calorimeter of the UA2 detector. The energy dependence of collective shape variables is investigated. The data, collected at the CERN $$\bar p$$ p Collider at $$\sqrt s = 630$$ GeV, exhibit strong variations in all these variables over the transverse energy range between 15 and 210 GeV, corresponding to substantial modifications in the structure of multihadronic final states. The evolution of the energy density distribution and of the collective shape variables shows a clear transition between two extreme dynamical regimes, respectively dominated byp T -limited phase space and by collimated two-jet configurations. A study of the relative populations of two-and three-jet systems reveals two different sources of configurations having three distinct lobes in the pattern of the energy-flow. A first component, steeply falling with energy, receives substantial contributions from soft parton collisions at lower transverse energies. Above 60 GeV a new hard component emerges, characterized by an approximately constant rate with respect to the dominant two-jet structures.

Published
1987

84. Measurement of production and properties of jets at the CERN $\overline{p}$p collider

Author

O. Kofoed-Hansen, M. Borghini, J. Teiger, S. Loucatos, Eric Lancon, H.M. Steiner, G. Fumagalli, B. Hahn, Ph. Bloch, Giancarlo Mantovani, Bruno Mansoulie, F. Bonaudi, H. Hänni, K. Borer, Adele Rimoldi, Michele Livan, Marco Fraternali, J. L. Siegrist, M. Polverel, W. Zeller, Peter Hansen, G. Parrour, B. Madsen, Allan G Clark, P. Mani, O. Gildemeister, F. Stocker, Livio Mapelli, Daniel Froidevaux, A. F. Rothenberg, F. Psstore, M. Banner, G. Sauvage, J. P. Repellin, L. Di Lella, C. Onions, H. Zaccone, A. R. Weidberg, Peter Jenni, R. Mollerud, B. Merkel, G. Stimpfl, Louis Fayard, P. Darriulat, J. M. Gaillard, Paolo Bagnaia, J. Schacher, V. G. Goggi, V. Hungerbühler, John H. L. Hansen, C. Conta, J. C. Chollet, A. Roussarie, Roberto Battiston, T. Himel, P. A. Dorsaz, Valerio Vercesi, J. Dines-Hansen, and H. Plothow-Besch

Subjects
Physics, Particle physics, Large Hadron Collider, Physics and Astronomy (miscellaneous), 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Hadron, 01 natural sciences, 7. Clean energy, Nuclear physics, Angular distribution, 0103 physical sciences, Transverse momentum, High Energy Physics::Experiment, Invariant mass, Rapidity, Nuclear Experiment, 010306 general physics, Engineering (miscellaneous), Particle Physics - Experiment
Abstract

The production and properties of high transverse momentum hadron jets have been measured in the UA2 experiment at the CERN $$\bar pp$$ Collider $$(\sqrt s = 540 GEV)$$ using a highly segmented total absorption calorimeter. The characteristics of a sample of two-jet events with invariant mass up to 200 GeV/c2 are discussed, including measurements of their fragmentation properties, angular and rapidity distributions, and the properties of the additional energy clusters accompanying the two-jet system. Cross sections for inclusive jet production in the jet transverse momentum range between 30 and 100 GeV/c and for the two-jet invariant mass distribution in the mass range from 60–200 GeV/c2 are reported.

Published
1983

85. Electron/hadron discrimination in the hyperon semileptonic decay experiments performed at the CERN SPS

Author

J. J. Thresher, B. Merkel, G. Sauvage, H. Plothow, J. M. Gaillard, R. Morand, J. C. Chollet, P. Igo-Kemenes, H. W. Siebert, J. Trischuk, R. Strub, R.J. Gray, M. Bourquin, K. P. Streit, B. Schiby, B.J. Saunders, W.M. Gibson, A. R. Fyfe, Y. Chatelus, Robert M Brown, J. P. Repellin, P. W. Jeffreys, C.N.P. Gee, R.J. Ott, Daniel Froidevaux, A. Degré, Vincent J Smith, 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 Heyd, Yvette

Subjects
Semileptonic decay, Physics, Particle physics, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], Physics::Instrumentation and Detectors, Hadron, General Engineering, Hyperon, Electron, Charged particle, Nuclear physics, Pion, Transition radiation, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Cherenkov radiation
Abstract

We describe an experimental arrangement which was used to discriminate between pions and electrons over the momentum range from 2 to 35 GeV/c in a series of semileptonic decay experiments performed in the CERN SPS charged hyperon beam. The set-up comprised two transition radiation detectors, a lead glass array, a threshold gas Cherenkov counter and a set of lead-scintillator shower counters. For the decays with one charged particle in the final state, the combined pion rejection provided by the transition radiation detectors and the lead glass array was 45000: 1 (Σ−→nπ−) with an electron efficiency of 76% ( Σ − → ne − υ ). In the decays producing three charged particles the rejection was 40000: 1 (σ−→Λπ−, Λ→pπ−) and the efficiency 70% (σ→Λ e − υ , Λ→ p π − and σ − →Λπ − , Λ→ pe − υ ) .

Published
1983

86. Observation of single isolated electrons of high transverse momentum in events with missing transverse energy at the CERN $\overline{p}$p collider

Author

F. Stocker, A. F. Rothenberg, L. Di Lella, Allan G Clark, P. Mani, G. Stimpfl, P. H. Hansen, Michele Livan, Marco Fraternali, G. Parrour, W. Zeller, J. Schacher, J. P. Repellin, A. Roussarie, A. R. Weidberg, Eric Lancon, G. Sauvage, M. Borghini, V. G. Goggi, H. Grote, V. Hungerbühler, R. Mollerud, H. Zaccone, B.S. Nilsson, Louis Fayard, J. M. Gaillard, J. Dines-Hansen, F. Bonaudi, M. Polverel, H. Plothow-Besch, John H. L. Hansen, Roberto Battiston, H. Hänni, G.C. Mantovani, Daniel Froidevaux, C. Conta, Livio Mapelli, M. Banner, K. Borer, Fr. Pastore, M. Mermikides, B. Madsen, P. Darriulat, O. Gildemeister, B. Merkel, J. Teiger, O. Kofoed-Hansen, B. Hahn, H.M. Steiner, Ph. Bloch, Bruno Mansoulie, J. L. Siegrist, J. C. Chollet, Peter Jenni, C. Onions, Sotiris Loucatos, P. A. Dorsaz, Valerio Vercesi, and T. Himel

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Electroweak interaction, Electron, law.invention, Nuclear physics, Azimuth, Transverse plane, law, Transverse momentum, Nuclear Experiment, Collider, Energy (signal processing), Particle Physics - Experiment
Abstract

We report the results of a search for single isolated electrons of high transverse momentum at the CERN p p collider. Above 15 GeV/c, four events are found having large missing transverse energy along a direction opposite in azimuth to that of the high-pT electron. Both the configuration of the events and their number are consistent with the expectations from the process p + p → W ± + anything , with W→e+ν, where W± is the charged Intermediate Vector Boso postulated by the unified electroweak theory.

Published
1983

87. MEASUREMENT OF THE STRONG COUPLING CONSTANT-ALPHA-S FROM A STUDY OF W BOSONS PRODUCED IN ASSOCIATION WITH JETS

Author

S. Loucatos, Giancarlo Mantovani, Lydia Iconomidou-Fayard, M. A. Parker, Adele Rimoldi, Marco Fraternali, M. Pepe, C. N. Booth, K. Borer, V. Ruhlmann, G. Sauvage, K. Jacobs, Giovanni Carboni, P. Lariccia, B. Merkel, P. Cenci, H. Zaccone, Valerio Vercesi, Roberto Battiston, J. P. Repellin, M. Banner, A. R. Weidberg, F. Pastore, R. Mollerud, Melody A. Swartz, Steinar Stapnes, J. Schacher, Louis Fayard, P. Darriulat, Allan G Clark, Eric Lancon, T. Pal, B. Hahn, C. Onions, K. Bernlöhr, Kevin Einsweiler, Roberto Ferrari, J. C. Chollet, F. Stocker, Chariclia Petridou, J. M. Gaillard, R. Ansari, Claus Gössling, B. De Lotto, John H. L. Hansen, L. Rasmussen, H. Plothow-Besch, M. Wunsch, D. Froidevaux, A. Roussarie, E. Iacopini, C. Conta, M. Polverel, J. Teiger, Peter Jenni, Vincenzo Cavasinni, P. H. Hansen, T. Del Prete, Paolo Bagnaia, N. Harnew, S. N. Tovey, Livio Mapelli, K. Meier, E. Hugentobler, M. Valdata-Nappi, W.Y. Tsang, L. Di Lella, K. Hara, J. Dines-Hansen, S. Lami, V. G. Goggi, R. Moning, M. Moniez, G. Parrour, Christophe Corona, Michele Livan, M. Morganti, Bruno Mansoulie, K. M. Borghini, E. E. Kluge, B. Madsen, O. Gildemeister, H. Hänni, F. Costantini, and O. Kofoed-Hansen

Subjects
Coupling constant, Physics, Quantum chromodynamics, Nuclear and High Energy Physics, Particle physics, Jet (fluid), Hadron, Elementary particle, law.invention, Nuclear physics, Particle decay, law, High Energy Physics::Experiment, Collider, Particle Physics - Experiment, Boson
Abstract

The UA2 experiment at the CERN p p Collider has identified a total sample of 251 W→eν events. Among this sample 221 events are found without jets and 29 with one jet. The yield of one-jet events relative to that of zero-jet events provides a measurement of the strong coupling constant: αs(Mw2)=0.13±0.03(stat)±0.03±(syst1)±0.02(syst2), where syst1 represents the experimental systematic error and syst2 is an estimate of the theoretical uncertainty.

Published
1988

88. Elastic electron scattering on helium 4

Author

J. P. Repellin, P. Lehmann, J. Lefrançois, and D.B. Isabelle

Subjects
Physics, Nuclear physics, Elastic scattering, Helium-4, Scattering, General Physics and Astronomy, Elastic electron, Mott scattering, Inelastic scattering, Small-angle neutron scattering
Published
1965

89. A Search For New Intermediate Vector Bosons and Excited Quarks Decaying To 2-jets At the Cern (p)over-bar-p Collider

Author

ALITTI, J, AMBROSINI, G, ANSARI, R, AUTIERO, D, BAREYRE, P, BERTRAM, I, BLAYLOCK, G, BONAMY, P, BORER, K, BOURLIAUD, M, BUSKULIC, D, CARBONI, G, CAVALLI, D, CAVASINNI, V, CENCI, P, CHOLLET, J, CONTA, C, COSTA, G, COSTANTINI, F, COZZI, L, CRAVERO, A, CURATOLO, M, DELLACQUA, A, DELPRETE, T, DEWOLF, R, DILELLA, L, DUCROS, Y, EGAN, G, EINSWEILER, K, ESPOSITO, B, FAYARD, L, FEDERSPIEL, A, FERRARI, R, FRATERNALI, M, FROIDEVAUX, D, FUMAGALLI, G, GAILLARD, J, GIANOTTI, F, GILDEMEISTER, O, GOSSLING, C, GOGGI, V, GRUNENDAHL, S, HARA, K, HELLMAN, S, HRIVNAC, J, HUFNAGEL, H, HUGENTOBLER, E, HULTQVIST, K, IACOPINI, E, INCANDELA, J, JAKOBS, K, JENNI, P, KLUGE, E, KURZ, N, LAMI, S, LARICCIA, P, LEFEBVRE, M, LINSSEN, L, LIVAN, M, LUBRANO, P, MAGNEVILLE, C, MALGERI, L, MANDELLI, L, MAPELLI, L, MAZZANTI, M, MEIER, K, MERKEL, B, MEYER, J, MONIEZ, M, MONING, R, MORGANTI, M, MULLER, L, MUNDAY, D, NESSI, M, NESSITEDALDI, F, ONIONS, C, PAL, T, PARKER, M, PARROUR, G, PASTORE, F, PENNACCHIO, E, PENTNEY, J, PEPE, M, PERINI, L, PETRIDOU, C, PETROFF, P, PLOTHOWBESCH, H, POLESELLO, G, POPPLETON, A, PRETZL, K, PRIMAVERA, M, PUNTURO, M, REPELLIN, J, RIMOLDI, A, SACCHI, M, SCAMPOLI, P, SCHACHER, J, SCHMIDT, B, SIMAK, V, SINGH, S, SONDERMANN, V, SPIWOKS, R, STAPNES, S, TALAMONTI, C, TONDINI, F, TOVEY, S, TSESMELIS, E, UNAL, G, VALDATANAPPI, M, VERCESI, V, WEIDBERG, A, WELLS, P, WHITE, T, WOOD, D, WOTTON, S, ZACCONE, H, ZYLBERSTEJN, A, J., Alitti, G., Ambrosini, R., Ansari, D., Autiero, P., Bareyre, I. A., Bertram, G., Blaylock, P., Bonamy, K., Borer, M., Bourliaud, D., Buskulic, G., Carboni, D., Cavalli, V., Cavasinni, P., Cenci, J. C., Chollet, C., Conta, G., Costa, F., Costantini, L., Cozzi, A., Cravero, M., Curatolo, A., Dellacqua, T., Delprete, R. S., Dewolf, L., Dilella, Y., Ducro, G. F., Egan, K. F., Einsweiler, B., Esposito, L., Fayard, A., Federspiel, R., Ferrari, M., Fraternali, D., Froidevaux, G., Fumagalli, J. M., Gaillard, F., Gianotti, O., Gildemeister, C., Gossling, V. G., Goggi, S., Grunendahl, K., Hara, S., Hellman, J., Hrivnac, H., Hufnagel, E., Hugentobler, K., Hultqvist, E., Iacopini, J., Incandela, K., Jakob, P., Jenni, E. E., Kluge, N., Kurz, S., Lami, P., Lariccia, M., Lefebvre, L., Linssen, M., Livan, P., Lubrano, C., Magneville, L., Malgeri, L., Mandelli, L., Mapelli, M., Mazzanti, K., Meier, B., Merkel, J. P., Meyer, M., Moniez, R., Moning, M., Morganti, L., Muller, D. J., Munday, M., Nessi, F., Nessitedaldi, C., Onion, T., Pal, M. A., Parker, G., Parrour, F., Pastore, E., Pennacchio, J. M., Pentney, M., Pepe, L., Perini, C., Petridou, P., Petroff, H., Plothowbesch, G., Polesello, A., Poppleton, K., Pretzl, M., Primavera, M., Punturo, J. P., Repellin, A., Rimoldi, M., Sacchi, Scampoli, Paola, J., Schacher, B., Schmidt, V., Simak, S. L., Singh, V., Sondermann, R., Spiwok, S., Stapne, C., Talamonti, F., Tondini, S. N., Tovey, E., Tsesmeli, G., Unal, M., Valdatanappi, V., Vercesi, A. R., Weidberg, P. S., Well, T. O., White, D. R., Wood, S. A., Wotton, H., Zaccone, and A., Zylberstejn

Subjects
Condensed Matter::Quantum Gases, LUND MONTE-CARLO, High Energy Physics::Phenomenology, HADRONIC PROCESSES, JETS, High Energy Physics::Experiment
Abstract

The two-jet invariant mass spectrum as measured in the UA2 experiment is used to search for additional heavy vector bosons decaying to two-jets. The mass of an additional W boson that couples to fermions with a V + A form is constrained to be greater than 261 GeV to the 90% confidence level. A limit on the production cross section of additional W and Z bosons is given as a function of the boson mass. A limit on the production of excited quarks is also given as a function of the excited quark mass.

Published
1993

90. Measurement of the Gluon Structure-function From Direct Photon Data At the Cern (p)over-bar-p Collider

Author

Alitti, J., Ambrosini, G., Ansari, R., Autiero, D., Bareyre, P., Bertram, Ia, Blaylock, G., Bonamy, P., Borer, K., Bourliaud, M., Buskulic, D., Carboni, G., Cavalli, D., Cavasinni, V., Cenci, P., Chollet, Jc, Conta, C., Costa, G., Costantini, F., Cozzi, L., Cravero, A., Curatolo, M., Dellacqua, A., Delprete, T., Dewolf, Rs, Dilella, L., Ducros, Y., Egan, Gf, Einsweiler, Kf, Esposito, B., Fayard, L., Federspiel, A., Ferrari, R., Fraternali, M., Froidevaux, D., Fumagalli, G., Gaillard, Jm, Gianotti, F., Gildemeister, O., Gossling, C., Goggi, Vg, Grunendahl, S., Hara, K., Hellman, S., Hrivnac, J., Hufnagel, H., Hugentobler, E., Hultqvist, K., Enrico Iacopini, Incandela, J., Jacobs, K., Jenni, P., Kluge, Ee, Kurz, N., Lami, S., Lariccia, P., Lefebvre, M., Linssen, L., Livan, M., Lubrano, P., Magneville, C., Malgeri, L., Mandelli, L., Mapelli, L., Mazzanti, M., Meier, K., Merkel, B., Meyer, Jp, Moniez, M., Moning, R., Morganti, M., Muller, L., Munday, Dj, Nessi, M., Nessitedaldi, F., Onions, C., Pal, T., Parker, Ma, Parrour, G., Pastore, F., Pennacchio, E., Pentney, Jm, Pepe, M., Perini, L., Petridou, C., Petroff, P., Plothowbesch, H., Polesello, G., Poppleton, A., Pretzl, K., Primavera, M., Punturo, M., Repellin, Jp, Rimoldi, A., Sacchi, M., Scampoli, P., Schacher, J., Schmidt, B., Simak, V., Singh, Sl, Sondermann, V., Spiwoks, R., Stapnes, S., Cinzia Talamonti, Tondini, F., Tovey, Sn, Tsesmelis, E., Unal, G., Valdatanappi, M., Vercesi, V., Weidberg, Ar, Wells, Ps, White, To, Wood, Dr, Wotton, Sa, Zaccone, H., Zylberstejn, A., J., Alitti, G., Ambrosini, R., Ansari, D., Autiero, P., Bareyre, I. A., Bertram, G., Blaylock, P., Bonamy, K., Borer, M., Bourliaud, D., Buskulic, G., Carboni, D., Cavalli, V., Cavasinni, P., Cenci, J. C., Chollet, C., Conta, G., Costa, F., Costantini, L., Cozzi, A., Cravero, M., Curatolo, A., Dellacqua, T., Delprete, R. S., Dewolf, L., Dilella, Y., Ducro, G. F., Egan, K. F., Einsweiler, B., Esposito, L., Fayard, A., Federspiel, R., Ferrari, M., Fraternali, D., Froidevaux, G., Fumagalli, J. M., Gaillard, F., Gianotti, O., Gildemeister, C., Gossling, V. G., Goggi, S., Grunendahl, K., Hara, S., Hellman, J., Hrivnac, H., Hufnagel, E., Hugentobler, K., Hultqvist, E., Iacopini, J., Incandela, K., Jacob, P., Jenni, E. E., Kluge, N., Kurz, S., Lami, P., Lariccia, M., Lefebvre, L., Linssen, M., Livan, P., Lubrano, C., Magneville, L., Malgeri, L., Mandelli, L., Mapelli, M., Mazzanti, K., Meier, B., Merkel, J. P., Meyer, M., Moniez, R., Moning, M., Morganti, L., Muller, D. J., Munday, M., Nessi, F., Nessitedaldi, C., Onion, T., Pal, M. A., Parker, G., Parrour, F., Pastore, E., Pennacchio, J. M., Pentney, M., Pepe, L., Perini, C., Petridou, P., Petroff, H., Plothowbesch, G., Polesello, A., Poppleton, K., Pretzl, M., Primavera, M., Punturo, J. P., Repellin, A., Rimoldi, M., Sacchi, Scampoli, Paola, J., Schacher, B., Schmidt, V., Simak, S. L., Singh, V., Sondermann, R., Spiwok, S., Stapne, C., Talamonti, F., Tondini, S. N., Tovey, E., Tsesmeli, G., Unal, M., Valdatanappi, V., Vercesi, A. R., Weidberg, P. S., Well, T. O., White, D. R., Wood, S. A., Wotton, H., Zaccone, and A., Zylberstejn

Subjects
SCINTILLATING FIBER DETECTOR, STRUCTURE-FUNCTION F2(X
Abstract

A measurement of the gluon structure fusion using direct photon events observed with the UA2 detector in ppBAR collisions at square-root s = 630 GeV is presented. The x-range covered by this analysis is between 0.049 and 0.207 and the Q2 range is between 280 GeV2 and 3670 GeV2. The data sample corresponds to an integrated luminosity of 7.14 pb-1. The results are found to be in good agreement with the gluon distributions measured in deep inelastic scattering experiments extrapolated to the UA2 Q2 values.

Published
1993

91. Direct Measurement of the W-gamma Coupling At the Cern Pbarp Collider

Author

ALITTI, J, AMBROSINI, G, ANSARI, R, AUTIERO, D, BAREYRE, P, BERTRAM, I, BLAYLOCK, G, BONAMY, P, BORER, K, BOURLIAUD, M, BUSKULIC, D, CARBONI, G, CAVALLI, D, CAVASINNI, V, CENCI, P, CHOLLET, J, CONTA, C, COSTA, G, COSTANTINI, F, COZZI, L, CRAVERO, A, CURATOLO, M, DELLACQUA, A, DELPRETE, T, DEWOLF, R, DILELLA, L, DUCROS, Y, EGAN, G, EINSWEILER, K, ESPOSITO, B, FAYARD, L, FEDERSPIEL, A, FERRARI, R, FRATERNALI, M, FROIDEVAUX, D, FUMAGALLI, G, GAILLARD, J, GIANOTTI, F, GILDEMEISTER, O, GOSSLING, C, GOGGI, V, GRUNENDAHL, S, HARA, K, HELLMAN, S, HRIVNAC, J, HUFNAGEL, H, HUGENTOBLER, E, HULTQVIST, K, IACOPINI, E, INCANDELA, J, JAKOBS, K, JENNI, P, KLUGE, E, KURZ, N, LAMI, S, LARICCIA, P, LEFEBVRE, M, LINSSEN, L, LIVAN, M, LUBRANO, P, MAGNEVILLE, C, MANDELLI, L, MAPELLI, L, MAZZANTI, M, MEIER, K, MERKEL, B, MEYER, J, MONIEZ, M, MONING, R, MORGANTI, M, MULLER, L, MUNDAY, D, NESSI, M, NESSITEDALDI, F, ONIONS, C, PAL, T, PARKER, M, PARROUR, G, PASTORE, F, PENNACCHIO, E, PENTNEY, J, PEPE, M, PERINI, L, PETRIDOU, C, PETROFF, P, PLOTHOWBESCH, H, POLESELLO, G, POPPLETON, A, PRETZL, K, PRIMAVERA, M, PUNTURO, M, REPELLIN, J, RIMOLDI, A, SACCHI, M, SCAMPOLI, P, SCHACHER, J, SCHMIDT, B, SIMAK, V, SINGH, S, SONDERMANN, V, SPIWOKS, R, STAPNES, S, TALAMONTI, C, TONDINI, F, TOVEY, S, TSESMELIS, E, UNAL, G, VALDATANAPPI, M, VERCESI, V, WEIDBERG, A, WELLS, P, WHITE, T, WOOD, D, WOTTON, S, ZACCONE, H, ZYLBERSTEJN, A, J., Alitti, G., Ambrosini, R., Ansari, D., Autiero, P., Bareyre, I. A., Bertram, G., Blaylock, P., Bonamy, K., Borer, M., Bourliaud, D., Buskulic, G., Carboni, D., Cavalli, V., Cavasinni, P., Cenci, J. C., Chollet, C., Conta, G., Costa, F., Costantini, L., Cozzi, A., Cravero, M., Curatolo, A., Dellacqua, T., Delprete, R. S., Dewolf, L., Dilella, Y., Ducro, G. F., Egan, K. F., Einsweiler, B., Esposito, L., Fayard, A., Federspiel, R., Ferrari, M., Fraternali, D., Froidevaux, G., Fumagalli, J. M., Gaillard, F., Gianotti, O., Gildemeister, C., Gossling, V. G., Goggi, S., Grunendahl, K., Hara, S., Hellman, J., Hrivnac, H., Hufnagel, E., Hugentobler, K., Hultqvist, E., Iacopini, J., Incandela, K., Jakob, P., Jenni, E. E., Kluge, N., Kurz, S., Lami, P., Lariccia, M., Lefebvre, L., Linssen, M., Livan, P., Lubrano, C., Magneville, L., Mandelli, L., Mapelli, M., Mazzanti, K., Meier, B., Merkel, J. P., Meyer, M., Moniez, R., Moning, M., Morganti, L., Muller, D. J., Munday, M., Nessi, F., Nessitedaldi, C., Onion, T., Pal, M. A., Parker, G., Parrour, F., Pastore, E., Pennacchio, J. M., Pentney, M., Pepe, L., Perini, C., Petridou, P., Petroff, H., Plothowbesch, G., Polesello, A., Poppleton, K., Pretzl, M., Primavera, M., Punturo, J. P., Repellin, A., Rimoldi, M., Sacchi, Scampoli, Paola, J., Schacher, B., Schmidt, V., Simak, S. L., Singh, V., Sondermann, R., Spiwok, S., Stapne, C., Talamonti, F., Tondini, S. N., Tovey, E., Tsesmeli, G., Unal, M., Valdatanappi, V., Vercesi, A. R., Weidberg, P. S., Well, T. O., White, D. R., Wood, S. A., Wotton, H., Zaccone, and A., Zylberstejn

Subjects
CHARGED WEAK BOSON, UA2 EXPERIMENT, ANOMALOUS MAGNETIC-MOMENT, SCINTILLATING FIBER DETECTOR
Abstract

The process ppBAR --> e-nu-gamma + X is studied as square-root s = 630 GeV. The observed signal is used to extract a direct measurement of the parameters-kappa and lambda which define the magnetic dipole and electric quadrupole moments of the W boson and therefore the WW-gamma coupling. We find kappa = 1(-2.2)+2.6 and lambda = 0(-1.8)+1.7 and their 95% confidence limits -3.5 < kappa < 5.9 and -3.6 < lambda < 3.5. The results are model independent and in good agreement with the standard model values, kappa = 1 and lambda = 0.

Published
1992

92. A Search For Scalar Leptoquarks At the Cern Pbarp Collider

Author

Alitti, J, Ambrosini, G, Ansari, R, Autiero, D, Bareyre, P, Bertram, Ia, Blaylock, G, Bonamy, P, Borer, K, Bourliaud, M, Buskulic, D, Carboni, G, Cavalli, D, Cavasinni, Vincenzo, Cenci, P, Chollet, Jc, Conta, C, Costa, G, Costantini, Flavio, Cozzi, L, Cravero, A, Curatolo, M, Dellacqua, A, Delprete, T, Dewolf, Rs, Dilella, L, Ducros, Y, Egan, Gf, Einsweiler, Kf, Esposito, B, Fayard, L, Federspiel, A, Ferrari, R, Fraternali, M, Froidevaux, D, Fumagalli, G, Gaillard, Jm, Gianotti, F, Gildemeister, O, Gossling, C, Goggi, Vg, Grunendahl, S, Hara, K, Hellman, S, Hrivnac, J, Hufnagel, H, Hugentobler, E, Hultqvist, K, Iacopini, E, Incandela, J, Jakobs, K, Jenni, P, Kluge, Ee, Kurz, N, Lami, S, Lariccia, P, Lefebvre, M, Linssen, L, Livan, M, Lubrano, P, Magneville, C, Mandelli, L, Mapelli, L, Mazzanti, M, Meier, K, Merkel, B, Meyer, Jp, Moniez, M, Moning, R, Morganti, M, Muller, L, Munday, Dj, Nessi, M, Nessitedaldi, F, Onions, C, Pal, T, Parker, Ma, Parrour, G, Pastore, F, Pennacchio, E, Pentney, Jm, Pepe, M, Perini, L, Petridou, C, Petroff, P, Plothowbesch, H, Polesello, G, Poppleton, A, Pretzl, K, Primavera, M, Punturo, M, Repellin, Jp, Rimoldi, A, Sacchi, M, Scampoli, P, Schacher, J, Schmidt, B, Simak, V, Singh, Sl, Sondermann, V, Spiwoks, R, Stapnes, S, Talamonti, C, Tondini, F, Tovey, Sn, Tsesmelis, E, Unal, G, Valdatanappi, M, Vercesi, V, Weidberg, Ar, Wells, Ps, White, To, Wood, Dr, Wotton, Sa, Zaccone, H, Zylberstejn, A., J., Alitti, G., Ambrosini, R., Ansari, D., Autiero, P., Bareyre, I. A., Bertram, G., Blaylock, P., Bonamy, K., Borer, M., Bourliaud, D., Buskulic, G., Carboni, D., Cavalli, V., Cavasinni, P., Cenci, J. C., Chollet, C., Conta, G., Costa, F., Costantini, L., Cozzi, A., Cravero, M., Curatolo, A., Dellacqua, T., Delprete, R. S., Dewolf, L., Dilella, Y., Ducro, G. F., Egan, K. F., Einsweiler, B., Esposito, L., Fayard, A., Federspiel, R., Ferrari, M., Fraternali, D., Froidevaux, G., Fumagalli, J. M., Gaillard, F., Gianotti, O., Gildemeister, C., Gossling, V. G., Goggi, S., Grunendahl, K., Hara, S., Hellman, J., Hrivnac, H., Hufnagel, E., Hugentobler, K., Hultqvist, E., Iacopini, J., Incandela, K., Jakob, P., Jenni, E. E., Kluge, N., Kurz, S., Lami, P., Lariccia, M., Lefebvre, L., Linssen, M., Livan, P., Lubrano, C., Magneville, L., Mandelli, L., Mapelli, M., Mazzanti, K., Meier, B., Merkel, J. P., Meyer, M., Moniez, R., Moning, M., Morganti, L., Muller, D. J., Munday, M., Nessi, F., Nessitedaldi, C., Onion, T., Pal, M. A., Parker, G., Parrour, F., Pastore, E., Pennacchio, J. M., Pentney, M., Pepe, L., Perini, C., Petridou, P., Petroff, H., Plothowbesch, G., Polesello, A., Poppleton, K., Pretzl, M., Primavera, M., Punturo, J. P., Repellin, A., Rimoldi, M., Sacchi, Scampoli, Paola, J., Schacher, B., Schmidt, V., Simak, S. L., Singh, V., Sondermann, R., Spiwok, S., Stapne, C., Talamonti, F., Tondini, S. N., Tovey, E., Tsesmeli, G., Unal, M., Valdatanappi, V., Vercesi, A. R., Weidberg, P. S., Well, T. O., White, D. R., Wood, S. A., Wotton, H., Zaccone, and A., Zylberstejn

Subjects
W-BOSONS, Physics::Instrumentation and Detectors, LUND MONTE-CARLO, High Energy Physics::Phenomenology, UA2 EXPERIMENT, JETS, High Energy Physics::Experiment
Abstract

A search has been made for scalar leptoquark pair production with the upgraded UA2 detector at the CERN ppBAR Coolider at square-root s = 630 GeV, investigating decays of the leptoquark into a quark and either an electron or an electron neutrino. From an event sample corresponding to an integrated luminosity of 13 pb-1 a lower limit has been determined for the mass of first generation leptoquarks, yielding 67 GeV (95% CL) for a scalar leptoquark decaying with a 50% branching ratio into a quark and an electron.

Published
1992

93. Experimental Limit On the Decay W+--]pi+-gamma At the Cern Pbarp Collider

Author

Alitti, J, Ambrosini, G, Ansari, R, Autiero, D, Bareyre, P, Bertram, Ia, Blaylock, G, Bonamy, P, Borer, K, Bourliaud, M, Buskulic, D, Carboni, G, Cavalli, D, Cavasinni, Vincenzo, Cenci, P, Chollet, Jc, Conta, C, Costa, G, Costantini, Flavio, Cozzi, L, Cravero, A, Curatolo, M, Dellacqua, A, Delprete, T, Dewolf, Rs, Dilella, L, Ducros, Y, Egan, Gf, Einsweiler, Kf, Esposito, B, Fayard, L, Federspiel, A, Ferrari, R, Fraternali, M, Froidevaux, D, Fumagalli, G, Gaillard, Jm, Gianotti, F, Gildemeister, O, Gossling, C, Goggi, Vg, Grunendahl, S, Hara, K, Hellman, S, Hrivnac, J, Hufnagel, H, Hugentobler, E, Hultqvist, K, Iacopini, E, Incandela, J, Jakobs, K, Jenni, P, Kluge, Ee, Kurz, N, Lami, S, Lariccia, P, Lefebvre, M, Linssen, L, Livan, M, Lubrano, P, Magneville, C, Mandelli, L, Mapelli, L, Mazzanti, M, Meier, K, Merkel, B, Meyer, Jp, Moniez, M, Moning, R, Morganti, M, Muller, L, Munday, Dj, Nessi, M, Nessitedaldi, F, Onions, C, Pal, T, Parker, Ma, Parrour, G, Pastore, F, Pennacchio, E, Pentney, Jm, Pepe, M, Perini, L, Petridou, C, Petroff, P, Plothowbesch, H, Polesello, G, Poppleton, A, Pretzl, K, Primavera, M, Punturo, M, Repellin, Jp, Rimoldi, A, Sacchi, M, Scampoli, P, Schacher, J, Schmidt, B, Simak, V, Singh, Sl, Sondermann, V, Spiwoks, R, Stapnes, S, Talamonti, C, Tondini, F, Tovey, Sn, Tsesmelis, E, Unal, G, Valdatanappi, M, Vercesi, V, Weidberg, Ar, Wells, Ps, White, To, Wood, Dr, Wotton, Sa, Zaccone, H, Zylberstejn, A., J., Alitti, G., Ambrosini, R., Ansari, D., Autiero, P., Bareyre, I. A., Bertram, G., Blaylock, P., Bonamy, K., Borer, M., Bourliaud, D., Buskulic, G., Carboni, D., Cavalli, V., Cavasinni, P., Cenci, J. C., Chollet, C., Conta, G., Costa, F., Costantini, L., Cozzi, A., Cravero, M., Curatolo, A., Dellacqua, T., Delprete, R. S., Dewolf, L., Dilella, Y., Ducro, G. F., Egan, K. F., Einsweiler, B., Esposito, L., Fayard, A., Federspiel, R., Ferrari, M., Fraternali, D., Froidevaux, G., Fumagalli, J. M., Gaillard, F., Gianotti, O., Gildemeister, C., Gossling, V. G., Goggi, S., Grunendahl, K., Hara, S., Hellman, J., Hrivnac, H., Hufnagel, E., Hugentobler, K., Hultqvist, E., Iacopini, J., Incandela, K., Jakob, P., Jenni, E. E., Kluge, N., Kurz, S., Lami, P., Lariccia, M., Lefebvre, L., Linssen, M., Livan, P., Lubrano, C., Magneville, L., Mandelli, L., Mapelli, M., Mazzanti, K., Meier, B., Merkel, J. P., Meyer, M., Moniez, R., Moning, M., Morganti, L., Muller, D. J., Munday, M., Nessi, F., Nessitedaldi, C., Onion, T., Pal, M. A., Parker, G., Parrour, F., Pastore, E., Pennacchio, J. M., Pentney, M., Pepe, L., Perini, C., Petridou, P., Petroff, H., Plothowbesch, G., Polesello, A., Poppleton, K., Pretzl, M., Primavera, M., Punturo, J. P., Repellin, A., Rimoldi, M., Sacchi, Scampoli, Paola, J., Schacher, B., Schmidt, V., Simak, S. L., Singh, V., Sondermann, R., Spiwok, S., Stapne, C., Talamonti, F., Tondini, S. N., Tovey, E., Tsesmeli, G., Unal, M., Valdatanappi, V., Vercesi, A. R., Weidberg, P. S., Well, T. O., White, D. R., Wood, S. A., Wotton, H., Zaccone, and A., Zylberstejn

Subjects
UA2 EXPERIMENT, SCINTILLATING FIBER DETECTOR
Abstract

Results are given on a search for the decay W+/- --> pi+/--gamma with the UA2 detector in ppBAR collisions at square-root s = 630 GeV. No signal for such a process is observed and upper limits on the ratio R = GAMMA(W+/- --> pi+/--gamma)/GAMMA(W+/- --> e+/--nu) < 4.9 x 10(-3) and on the branching ratio BR(W+/- --> pi+/--gamma) < 5.4 x 10(-4) are derived at 95% confidence level.

Published
1992

94. Measurement of W-production and Z-production Cross-sections At the Cern Pbarp Collider

Author

Alitti, J, Ansari, R, Ansorge, Re, Bagnaia, P, Bareyre, P, Blaylock, G, Bonamy, P, Bonesini, M, Booth, Cn, Borer, K, Buskulic, D, Carboni, G, Cavalli, D, Cavasinni, Vincenzo, Cenci, P, Chollet, Jc, Conta, C, Costa, G, Costantini, Flavio, Crittenden, J, Dellacqua, A, Delotto, B, Delprete, T, Dewolf, Rs, Dilella, L, Egan, Gf, Einsweiler, Kf, Fayard, L, Federspiel, A, Ferrari, R, Fraternali, M, Froidevaux, D, Fumagalli, G, Gaillard, Jm, Gianotti, F, Gildemeister, O, Gossling, C, Goggi, Vg, Grunendahl, S, Hara, K, Hellman, S, Hugentobler, E, Hultqvist, K, Iacopini, E, Incandela, J, Jakobs, K, Jenni, P, Kluge, Ee, Kurz, N, Lami, S, Lariccia, P, Lefebvre, M, Linssen, L, Lisowski, B, Livan, M, Lubrano, P, Magneville, C, Mandelli, L, Mapelli, L, Mazzanti, M, Meier, K, Merkel, B, Meyer, Jp, Moniez, M, Moning, R, Morganti, M, Muller, L, Munday, Dj, Onions, C, Pal, T, Parker, Ma, Parrour, G, Pastore, F, Pennacchio, E, Pentney, Jm, Pepe, M, Perini, L, Petridou, C, Petroff, P, Plothowbesch, H, Polesello, G, Poppleton, A, Punturo, M, Rasmussen, L, Repellin, Jp, Rimoldi, A, Rushbrooke, Jg, Scampoli, P, Schacher, J, Singh, Sl, Stapnes, S, Stirling, Av, Tondini, F, Tovey, Sn, Tsesmelis, E, Valdatanappi, M, Vercesi, V, Weidberg, Ar, Wells, Ps, White, To, Wood, Dr, Wotton, Sa, Zaccone, H., J., Alitti, R., Ansari, R. E., Ansorge, P., Bagnaia, P., Bareyre, G., Blaylock, P., Bonamy, M., Bonesini, C. N., Booth, K., Borer, D., Buskulic, G., Carboni, D., Cavalli, V., Cavasinni, P., Cenci, J. C., Chollet, C., Conta, G., Costa, F., Costantini, J., Crittenden, A., Dellacqua, B., Delotto, T., Delprete, R. S., Dewolf, L., Dilella, G. F., Egan, K. F., Einsweiler, L., Fayard, A., Federspiel, R., Ferrari, M., Fraternali, D., Froidevaux, G., Fumagalli, J. M., Gaillard, F., Gianotti, O., Gildemeister, C., Gossling, V. G., Goggi, S., Grunendahl, K., Hara, S., Hellman, E., Hugentobler, K., Hultqvist, E., Iacopini, J., Incandela, K., Jakob, P., Jenni, E. E., Kluge, N., Kurz, S., Lami, P., Lariccia, M., Lefebvre, L., Linssen, B., Lisowski, M., Livan, P., Lubrano, C., Magneville, L., Mandelli, L., Mapelli, M., Mazzanti, K., Meier, B., Merkel, J. P., Meyer, M., Moniez, R., Moning, M., Morganti, L., Muller, D. J., Munday, C., Onion, T., Pal, M. A., Parker, G., Parrour, F., Pastore, E., Pennacchio, J. M., Pentney, M., Pepe, L., Perini, C., Petridou, P., Petroff, H., Plothowbesch, G., Polesello, A., Poppleton, M., Punturo, L., Rasmussen, J. P., Repellin, A., Rimoldi, J. G., Rushbrooke, Scampoli, Paola, J., Schacher, S. L., Singh, S., Stapne, A. V., Stirling, F., Tondini, S. N., Tovey, E., Tsesmeli, M., Valdatanappi, V., Vercesi, A. R., Weidberg, P. S., Well, T. O., White, D. R., Wood, S. A., Wotton, and H., Zaccone

Published
1990

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