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189 results on '"G. Backenstoss"'

1. transitions monitored by strong interactions: a new determination of the KL–KS mass difference

Author: R. Le Gac, M. Schafer, P.-R. Kettle, J. R. Fry, R. Gamet, D. Zimmerman, A. Muller, L. Sakeliou, Per Carlson, L. Tauscher, A. Ealet, P. Bargassa, D. Zavrtanik, H.-J. Gerber, P. Bloch, P. Pavlopoulos, M.B. Chertok, P. Weber, F. Blanc, Sotirios Vlachos, T. Ruf, B. L. Roberts, K. Jon-And, Marcin Wladyslaw Wolter, G. Polivka, Panagiotis Kokkas, J. Derre, A. Angelopoulos, B. Pagels, Andrej Filipcic, M. Mikuž, D. Francis, Nikolaos Manthos, Lukas A. Schaller, W. Fetscher, O. Wigger, Jeffrey Boone Miller, E. Gabathuler, R. Rickenbach, Mats Danielsson, F. Henry-Couannier, C. Thibault, M. Fidecaro, O. Behnke, A. Haselden, F. Montanet, C. Eleftheriadis, A. Benelli, F. Leimgruber, A. Schopper, C.W.E. van Eijk, T. Nakada, P.J. Hayman, Michael C. Carroll, Marc Dejardin, R.W. Hollander, I. Papadopoulos, G. Backenstoss, V. Bertin, Elie Aslanides, R. Kreuger, C. Touramanis, Igor Mandić, A. Go, G. Marel, T. Schietinger, F. Touchard, and E. Cawley
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Amplitude, CPT symmetry, High Energy Physics::Phenomenology, High Energy Physics::Experiment, Strangeness, Nuclear Experiment
Abstract: The CPLEAR set-up (modified) has been used to determine the KL–KS mass difference by a method where neutral-kaon strangeness oscillations are monitored through kaon strong interactions, rather than semileptonic decays, thus requiring no assumptions on CPT invariance for the decay amplitudes. The result, Δm=(0.5343±0.0063stat±0.0025syst)×1010ℏ/s, provides a valuable input for CPT tests.
Published: 2001
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2. K0– mass and decay-width differences: CPLEAR evaluation

Author: V. Bertin, M. Schafer, L. Tauscher, P. Bloch, R. Le Gac, M. Wolter, E. Cawley, R. Kreuger, Marc Dejardin, F. Touchard, C. Eleftheriadis, P. Weber, A. Haselden, I. Mandić, J. R. Fry, Panagiotis Kokkas, B.L. Roberts, O. Behnke, W. Fetscher, D. Francis, T. Nakada, G. Marel, I. Papadopoulos, A. Angelopoulos, K. Jon-And, F. Leimgruber, A. Schopper, S. Vlachos, F. Montanet, P.J. Hayman, O. Wigger, A. Go, A. Ealet, D. Zimmerman, P.-R. Kettle, P. Carlson, A. Filipčič, T. Ruf, A. Apostolakis, F. Henry-Couannier, M. Fidecaro, R.W. Hollander, Jeffrey Boone Miller, Elie Aslanides, N. Manthos, C. Thibault, Michael C. Carroll, J. Derre, G. Polivka, D. Zavrtanik, P. Pavlopoulos, A. Muller, C. Touramanis, R. Gamet, F. Blanc, H.-J. Gerber, L.A. Schaller, Mats Danielsson, B. Pagels, A. Benelli, C.W.E. van Eijk, E. Gabathuler, R. Rickenbach, T. Schietinger, M.B. Chertok, G. Backenstoss, P. Bargassa, and M. Mikuž
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Matrix (mathematics), Amplitude, CPT symmetry, Quantum mechanics, Diagonal
Abstract: The CPT-violation parameters Re(δ) and Im(δ) determined recently by CPLEAR are used to evaluate the K0– K 0 mass and decay-width differences, as given by the difference between the diagonal elements of the neutral-kaon mixing matrix (M−iΓ/2). The results – (M K 0 K 0 −M K 0 K 0 )=(−1.5±2.0)×10 −18 GeV and (Γ K 0 K 0 −Γ K 0 K 0 )=(3.9±4.2)×10 −18 GeV – are consistent with CPT invariance. The CPT invariance is also shown to hold within a few times 10−3–10−4 for many of the amplitudes describing neutral-kaon decays to different final states.
Published: 1999
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3. Pion correlations and resonance effects in annihilation at rest

Author: C. Touramanis, R. Le Gac, P. Weber, J. R. Fry, V. Bertin, Elie Aslanides, E. Cawley, A. Benelli, C.W.E. van Eijk, P. Pavlopoulos, A. Haselden, F. Montanet, R.W. Hollander, L. Tauscher, M.B. Chertok, Jeffrey Boone Miller, F. Touchard, K. Jon-And, P.-R. Kettle, W. Fetscher, A. Muller, T. Ruf, M.P. Locher, E. Gabathuler, Mats Danielsson, R. Rickenbach, F. Henry-Couannier, A. Ealet, T. Schietinger, F. Blanc, M. Schafer, I. Papadopoulos, Sotirios Vlachos, A. Angelopoulos, Nikolaos Manthos, B. Pagels, Panagiotis Kokkas, Igor Mandić, Danilo Zavrtanik, L. Faravel, P. Bloch, A. Go, M. Fidecaro, G. Backenstoss, C. Thibault, C. Eleftheriadis, Marc Dejardin, Michael C. Carroll, T. Nakada, Per Carlson, R. Kreuger, G. Polivka, A. Apostolakis, G. Marel, D. Zimmerman, Andrej Filipcic, H.-J. Gerber, Lukas A. Schaller, Marcin Wladyslaw Wolter, O. Wigger, J. Derre, O. Behnke, B.L. Roberts, F. Leimgruber, A. Schopper, P.J. Hayman, M. Mikuž, D. Francis, V.E. Markushin, R. Gamet, and P. Bargassa
Subjects: Nuclear physics, Rest (physics), Physics, Correlation, Nuclear and High Energy Physics, Particle physics, Pion, Annihilation, Invariant mass, Function (mathematics), Resonance (particle physics), Event (particle physics)
Abstract: We study ππ correlations in the exclusive reactions p p → 2π + 2π − and p p → 2π + 2π − π 0 at rest with complete reconstruction of the kinematics for each event. A new analysis technique has been developed which is model independent. With this new technique, which relies on double-differential distributions, no reference sample is needed to extract the correlation signal. The correlations are studied as a function of the four-pion invariant mass.
Published: 1999
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4. Determination of the T- and CPT-violation parameters in the neutral-kaon system using the Bell–Steinberger relation and data from CPLEAR

Author: G. Polivka, Michael C. Carroll, D. Zavrtanik, F. Touchard, M. Wolter, E. Cawley, T. Ruf, C. Touramanis, R. Kreuger, A. Apostolakis, L. Sakeliou, C. Thibault, A. Haselden, P. Weber, G. Marel, O. Behnke, P. Bargassa, L. Tauscher, F. Henry-Couannier, E. Gabathuler, R. Rickenbach, P. Pavlopoulos, J. Derre, C. Eleftheriadis, S. Vlachos, R.W. Hollander, A. Go, F. Leimgruber, P. Carlson, V. Bertin, T. Schietinger, A. Schopper, M.B. Chertok, P.J. Hayman, B.L. Roberts, C.W.E. van Eijk, R. Le Gac, M. Mikuž, E. Aslanides, A. Ealet, Panagiotis Kokkas, J. R. Fry, M. Schafer, Mats Danielsson, I. Papadopoulos, G. Backenstoss, K. Jon-And, P. Bloch, M. Fidecaro, I. Mandić, L.A. Schaller, A. Muller, A. Benelli, D. Francis, N. Manthos, H.-J. Gerber, O. Wigger, R. Gamet, D. Zimmerman, P.-R. Kettle, Jeffrey Boone Miller, F. Blanc, B. Pagels, A. Filipčič, T. Nakada, Marc Dejardin, W. Fetscher, F. Montanet, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), CPLEAR, Lorgeril, Jocelyne, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], Unitarity, 010308 nuclear & particles physics, media_common.quotation_subject, Value (computer science), 01 natural sciences, Asymmetry, Matrix (mathematics), 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, 010306 general physics, Particle Physics - Experiment, Mixing (physics), media_common
Abstract: Data from the CPLEAR experiment, together with the most recent world averages for some of the neutral-kaon parameters, were constrained with the Bell--Steinberger (or unitarity) relation, allowing the T-violation parameter $\ree$ and the CPT-violation parameter $\imd$ of the neutral-kaon mixing matrix to be determined with an increased accuracy: $\ree = (164.9 \pm 2.5)\times 10^{-5}$, $\imd = ( 2.4 \pm 5.0)\times 10^{-5}$. Moreover, the constraint allows the CPT-violation parameter for the neutral-kaon semileptonic decays, $\rey$, to be determined for the first time. The $\Delta S \neq \Delta Q$ parameters $\rexm$ and $\imxp$ are given with an increased accuracy. The quantity $\mathrm{Re}(y~+~x_-)$, which enters the T-violation CPLEAR asymmetry previously published, is determined to be $(0.2 \pm 0.3)\times 10^{-3}$. The value obtained for $\red$ is in agreement with the one resulting from a previous unconstrained fit and has a slightly smaller error.
Published: 1999
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5. First direct observation of time-reversal non-invariance in the neutral-kaon system

Author: Claudio Santoni, P.-R. Kettle, T. Nakada, Lukas A. Schaller, Danilo Zavrtanik, P. Bloch, R. Gamet, Sotirios Vlachos, Andrej Filipcic, A. Muller, Mats Danielsson, O. Behnke, A. Angelopoulos, V. Bertin, H.-J. Gerber, D. Zimmerman, L. Faravel, M. Fidecaro, M. Schafer, F. Leimgruber, L. Tauscher, P. Carlson, A. Schopper, P. Bargassa, E. Gabathuler, R. Rickenbach, A. Haselden, Jeffrey Boone Miller, P.J. Hayman, C. Thibault, G. Backenstoss, F. Montanet, M. Mikuž, D. Francis, Marcin Wladyslaw Wolter, A. Ealet, T. Ruf, J. Derre, P. Pavlopoulos, P. Weber, R.W. Hollander, C. Eleftheriadis, O. Wigger, R. Le Gac, M.B. Chertok, Nikolaos Manthos, A.J.P.L. Policarpo, Panagiotis Kokkas, E. Aslanides, I. Papadopoulos, K. Jon-And, Stef. Charalambous, J. R. Fry, F. Blanc, G. Polivka, B.L. Roberts, B. Pagels, W. Fetscher, C. Touramanis, F. Henry-Couannier, A. Benelli, C.W.E. van Eijk, Igor Mandić, A. Go, Marc Dejardin, Michael C. Carroll, T. Schietinger, R. Kreuger, A. Apostolakis, G. Marel, E. Cawley, and F. Touchard
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, High Energy Physics::Phenomenology, Nuclear Theory, Direct observation, Charge (physics), Strangeness, Asymmetry, Decay time, High Energy Physics::Experiment, Nuclear Experiment, Particle Physics - Experiment, media_common, Lepton
Abstract: We report on the first observation of time-reversal symmetry violation through a comparison of the probabilities of K 0 transforming into K0 and K0 into K 0 as a function of the neutral-kaon eigentime t. The comparison is based on the analysis of the neutral-kaon semileptonic decays recorded in the CPLEAR experiment. There, the strangeness of the neutral kaon at time t=0 was tagged by the kaon charge in the reaction p p → K ± π ∓ K 0 ( K 0 ) at rest, whereas the strangeness of the kaon at the decay time t=τ was tagged by the lepton charge in the final state. An average decay-rate asymmetry 〈 R( K 0 t=0 → e + π − ν t=τ )−R( K 0 t=0 → e − π + ν t=τ ) R( K 0 t=0 → e + π − ν t=τ )+R( K 0 t=0 → e − π + ν t=τ ) 〉=(6.6±1.3 stat ±1.0 syst )×10 −3 was measured over the interval 1 τ S τ S , thus leading to evidence for time-reversal non-invariance.
Published: 1998
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6. Two step processes in pion single charge exchange on2HatTπ+=239MeV

Author: B. Kotliński, Urs Sennhauser, N.K. Gregory, A.O. Mateos, M. Kroedel, H.J. Weyer, K. Michaelian, H. Döbbeling, D. Rowntree, Darko Androić, P. A. M. Gram, Avraham Klein, Miroslav Furić, H. Ullrich, Tomislav Petković, T. Dooling, R. Trezeciak, M.H. Wang, A. Hoffart, G. S. Kyle, H. Breuer, M. Wang, Mirko Planinic, Neven Simicevic, J. Köhler, M. Wildi, G. Backenstoss, K. E. Wilson, A. Lehmann, C. H. Q. Ingram, R. P. Redwine, K. Koch, and Damir Bosnar
Subjects: Physics, Nuclear and High Energy Physics, Nuclear Theory, Two step, Kinetic energy, Nuclear physics, Cross section (physics), Pion, Energy spectrum, Pi, Physics::Accelerator Physics, Atomic physics, Nuclear Experiment, Nucleon, Charge exchange
Abstract: Results from a measurement of the reaction 2H(+,pp)  at T+ = 239 MeV are presented. Because two protons were detected, the measurement was sensitive to events which involved both nucleons in a substantial way. Differential distributions are compared to the predictions of simple models. An integrated cross section for SCX (single charge exchange), with the emmision of two protons each with kinetic energy >25 MeV, is presented
Published: 1998
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7. Total and partial pion absorption cross sections on4Hein the Δ resonance region

Author: Miroslav Furić, M.H. Wang, Urs Sennhauser, M. Kroedel, A.O. Mateos, H. Ullrich, R. Trezeciak, Damir Bosnar, Mirko Planinic, Tomislav Petković, K. E. Wilson, B. Kotliński, H.J. Weyer, H. Döbbeling, J. Köhler, D. Rowntree, M. Wang, A. Lehmann, Darko Androić, K. Michaelian, P. A. M. Gram, R. P. Redwine, K. Koch, Avraham Klein, Neven Simicevic, Quentin Ingram, G. Backenstoss, G. S. Kyle, M. Wildi, N.K. Gregory, H. Breuer, A. Hoffart, and T. Dooling
Subjects: Physics, Nuclear and High Energy Physics, Nuclear Theory, Absorption cross section, Solid angle, Kinetic energy, Resonance (particle physics), Delta baryon, Nuclear physics, Pion, Nuclear cross section, Atomic physics, Nuclear Experiment, Absorption (electromagnetic radiation)
Abstract: This paper presents a large solid angle measurement of the positive pion absorption cross section on 4 He and its decomposition into partial channels. The total absorption cross sections at incident pion kinetic energies of Tp1570, 118, 162, and 239 MeV are 3565, 5264, 5165, and 2762 mb, respectively. These values are lower than those reported in some previous experiments. At all pion energies a large fraction of the absorption cross section is due to multinucleon channels. @S0556-2813~98!03108-2#
Published: 1998
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8. Search for CP violation in the decay of tagged and K0 to π0π0π0

Author: F. Touchard, C. Touramanis, T. Schietinger, P. Weber, M.B. Chertok, M. Fidecaro, R. Le Gac, L. Faravel, O. Wigger, S. Vlachos, A. Apostolakis, J. R. Fry, L.A. Schaller, A. Benelli, C.W.E. van Eijk, G. Backenstoss, F. Henry-Couannier, V. Bertin, M. Schafer, N. Manthos, T. Nakada, O. Behnke, A. Angelopoulos, L. Tauscher, P. Bargassa, C. Thibault, Jeffrey Boone Miller, R. Kreuger, Mats Danielsson, G. Polivka, M. Mikuž, I. Mandić, F. Leimgruber, A. Schopper, E. Gabathuler, R. Rickenbach, J. Derre, G. Marel, F. Blanc, M. Wolter, E. Cawley, Elie Aslanides, A. Filipčič, Panagiotis Kokkas, B. L. Roberts, A. Haselden, D. Zimmerman, P.J. Hayman, W. Fetscher, P. Carlson, B. Pagels, Michael C. Carroll, I. Papadopoulos, K. Jon-And, P.-R. Kettle, P. Bloch, F. Montanet, D. Zavrtanik, A. Ealet, R. Gamet, R.W. Hollander, P. Pavlopoulos, T. Ruf, D. Francis, Marc Dejardin, A. Go, C. Eleftheriadis, A. Muller, and H.-J. Gerber
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Amplitude, Branching fraction, CPT symmetry, media_common.quotation_subject, Order (group theory), CP violation, Asymmetry, media_common
Abstract: The CPLEAR experiment measured the eigentime-dependent asymmetry in the rates of initially tagged K 0 and K 0 decaying to π 0 π 0 π 0 in order to study the interference between the CP-violating K S and the CP-conserving K L decay amplitudes. Without assuming CPT invariance, we obtain for the CP-violation parameter η 000 the values Re( η 000 )=0.18±0.14 stat. ±0.06 syst. and Im( η 000 )=0.15±0.20 stat. ±0.03 syst. . Requiring Re( η 000 ) to be equal to Re(ϵ) we obtain Im( η 000 )=−0.05±0.12 stat. ±0.05 syst. . The corresponding upper limit for the branching ratio of the K S →π 0 π 0 π 0 decay is deduced to be B K S →π 0 π 0 π 0 −5 at the 90% confidence level.
Published: 1998
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9. An EPR experiment testing the non-separability of the wave function

Author: M. Schafer, B.L. Roberts, Igor Mandić, V. Bertin, Elie Aslanides, P. Weber, R. Ferreira-Marques, W. Fetscher, H.-J. Gerber, Nikolaos Manthos, P.-R. Kettle, A. Benelli, C.W.E. van Eijk, C. Touramanis, Danilo Zavrtanik, Panagiotis Kokkas, A. Go, A. Muller, R. Kreuger, R. Le Gac, T. Nakada, G. Polivka, Jeffrey Boone Miller, P. Bloch, Marcin Wladyslaw Wolter, Ph. Schune, T. Schietinger, L. Tauscher, J. Derre, J. R. Fry, F. Blanc, A.J.P.L. Policarpo, A. Haselden, A. Ealet, Sotirios Vlachos, Lukas A. Schaller, C. Kochowski, Andrej Filipcic, G. Marel, T. Ruf, F. Henry-Couannier, B. Pagels, E. Gabathuler, M. Mikuž, D. Francis, R. Rickenbach, O. Behnke, P. Pavlopoulos, R.W. Hollander, M. Fidecaro, F. Leimgruber, A. Schopper, Ch Yèche, P.J. Hayman, M.B. Chertok, Marc Dejardin, G. Chardin, R. Gamet, I. Papadopoulos, P. Bargassa, K. Jon-And, O. Wigger, G. Backenstoss, Claude Guyot, Per Carlson, C. Thibault, A. Apostolakis, C. Eleftheriadis, Michael C. Carroll, E. Hubert, A. Cody, F. Touchard, E. Cawley, and F. Montanet
Subjects: Physics, Nuclear and High Energy Physics, symbols.namesake, Particle physics, Factorization, Detector, Strong interaction, symbols, EPR paradox, Function (mathematics), Strangeness
Abstract: The EPR-type strangeness correlation in the K0 system produced in the reaction at rest has been tested using the CPLEAR detector. The strangeness was tagged via strong interaction with absorbers away from the creation point. The results are consistent with the QM non-separability of the wave function and exclude a spontaneous wave-function factorisation at creation (CL >99.99%). http://www.sciencedirect.com/science/article/B6TVN-3TCVWTV-3P/1/15e4df323d79f1e3a0585a106b160a36
Published: 1998
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10. Direct determination of two-pion correlations for pp→ 2π+2π− annihilation at rest

Author: Ioannis Evangelou, O. Wigger, L. Sakeliou, Per Carlson, Panagiotis Kokkas, W. Fetscher, F. Henry-Couannier, Ch Yèche, Sotirios Vlachos, G. Chardin, V.E. Markushin, M.B. Chertok, G. Backenstoss, Danilo Zavrtanik, A. Angelopoulos, H.-J. Gerber, M.P. Locher, K. Jon-And, L. Tauscher, D. Garreta, P. Weber, J. Pinto da Cunha, C. Thibault, P. Sanders, E. Machado, C. Eleftheriadis, Nikolaos Manthos, R. Gamet, A. Go, R. Le Gac, A. Liolios, O. Behnke, A.J.P.L. Policarpo, Mats Danielsson, E. Gabathuler, R. Rickenbach, P. Bargassa, Marcin Wladyslaw Wolter, E. Hubert, A. Benelli, C.W.E. van Eijk, J. Derre, F. Leimgruber, A. Schopper, Igor Mandić, M. Fidecaro, Stef. Charalambous, J. R. Fry, P. Bloch, P.J. Hayman, Jeffrey Boone Miller, A. Haselden, V. Bertin, A. Soares, D. Zimmerman, G. Polivka, Elie Aslanides, T. Ruf, Lukas A. Schaller, Michael C. Carroll, A. Apostolakis, M. Schafer, L. Faravel, C. Touramanis, R.W. Hollander, F. Blanc, Frixos A Triantis, P. Pavlopoulos, Marc Dejardin, B.L. Roberts, I. Papadopoulos, R. Kreuger, T. Schietinger, P.-R. Kettle, B. Pagels, G. Marel, A. Muller, M. Mikuž, T. Nakada, D. Francis, A. Ealet, R. Ferreira-Marques, E. Cawley, A. Cody, Andrej Filipcic, E. van Beveren, F. Touchard, João Carvalho, and F. Montanet
Subjects: Physics, Particle physics, Annihilation, Physics and Astronomy (miscellaneous), Skyrmion, Nuclear Theory, Charge (physics), Radius, Momentum, Nuclear physics, Pion, Symmetrization, Nuclear Experiment, Engineering (miscellaneous), Event (particle physics)
Abstract: We study ππ correlations in the exclusive reaction pp → 2π+2π− at rest measured by the CPLEAR experiment. Avoiding the introduction of an arbitrary reference sample, we analyse differential distributions for equal charge pion pairs removing the phase-space factor event by event. A peak at small relative momenta is most pronounced for large total momentum of the pair. The physical implications of bosonic symmetrization for the properties of the pion source, in particular its radius, are briefly discussed. The two extremes considered are the chaotic Hanbury-Brown-Twiss mechanism and the coherent Skyrmion model.
Published: 1998
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11. Measurement of the CP-violation parameter η00 using tagged and K0

Author: F. Leimgruber, Lukas A. Schaller, A. Schopper, E. Hubert, R. Kreuger, L. Faravel, P.J. Hayman, R. Ferreira-Marques, O. Wigger, Ch Yèche, V. Bertin, G. Marel, Elie Aslanides, P. Pavlopoulos, A. Go, D. Zimmerman, C. Touramanis, Mats Danielsson, Frixos A Triantis, Sotirios Vlachos, Ioannis Evangelou, Andrej Filipcic, T. Ruf, R. Le Gac, W. Fetscher, L. Sakeliou, A. Angelopoulos, J. Pinto da Cunha, A. Muller, C. Thibault, A. Benelli, C.W.E. van Eijk, E. Gabathuler, R. Rickenbach, R. Gamet, Per Carlson, F. Henry-Couannier, A. Haselden, Igor Mandić, C. Eleftheriadis, P. Bloch, Nikolaos Manthos, B. L. Roberts, Panagiotis Kokkas, A. Liolios, A. Ealet, João Carvalho, F. Montanet, F. Blanc, T. Nakada, P.R. Kettle, L. Tauscher, J. R. Fry, A.J.P.L. Policarpo, R.W. Hollander, Michael C. Carroll, B. Pagels, E. Machado, T. Schietinger, Danilo Zavrtanik, M.B. Chertok, Jeffrey Boone Miller, Marc Dejardin, K. Jon-And, M. Mikuž, D. Francis, P. Sanders, M. Fidecaro, P. Weber, M. Schafer, P. Bargassa, G. Chardin, A. Apostolakis, G. Backenstoss, D. Garreta, I. Papadopoulos, Stef. Charalambous, H.-J. Gerber, G. Polivka, E. van Beveren, F. Touchard, Marcin Wladyslaw Wolter, J. Derre, E. Cawley, A. Cody, and O. Behnke
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Complete data, media_common.quotation_subject, CP violation, Asymmetry, media_common
Abstract: The CP-violation parameter \etazero\ is determined through the eigentime-dependent asymmetry in the rates of initially tagged \kzerob\ and \kzero\ decaying to \pizero \pizero. From the analysis of the complete data set we obtain the values $ \absetazero = [2.47 \pm 0.31_{\mbox{stat.}} \pm 0.24_{\mbox{syst.}}] \times 10^{-3} $ and $ \phizero = 42.0^0 \pm 5.6_{\mbox{stat.}}^0 \pm 1.9_{\mbox{syst.}}^0 % \pm 0.3_{\mbox{$\Delta$m}}^0 . $
Published: 1998
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12. Measurement of CP,T and CPT violation parameters in the Neutral Kaon system at CPLEAR

Author: Andrej Filipcic, D. Francis, Marko Mikuz, A. Benelli, C.W.E. van Eijk, T. Schietinger, R. Le Gac, M. Fidecaro, C. Touramanis, Claude Guyot, E. Cawley, Ph. Schune, João Carvalho, F. Montanet, Frixos A Triantis, S. Vlachos, R. Ferreira-Marques, A. Ealet, P. Bloch, Ioannis Evangelou, Ch Yèche, B. Eckart, Elie Aslanides, F. Blanc, L. Sakeliou, J. R. Fry, C. Santoni, P. Kokkas, C. Kochowski, Marcin Wladyslaw Wolter, I. Papadopoulos, A. Haselden, E. van Beveren, A. Apostolakis, J. Derre, F. Touchard, T. Ruf, B. Pagels, O. Wigger, F. Leimgruber, Igor Mandić, D. Garreta, W. Fetscher, G. Polivka, R.W. Hollander, A. Go, R. Rickenbach, R. Gamet, A. Cody, T. Alhalel, M. Carroll, H.-J. Gerber, O. Behnke, A. Soares, J. Pinto da Cunha, P.R. Kettle, L. Tauscher, C. Felder, Mats Danielsson, R. Adler, E. Machado, P. Fassnacht, E. Hubert, A.J.P.L. Policarpo, A. Schopper, F. Henry-Couannier, D. Zimmerman, P. Carlson, P.J. Hayman, P. Sanders, Marc Dejardin, M.B. Chertok, Jeffrey Boone Miller, P. Weber, E. Gabathuler, V. Bertin, A. Angelopoulos, K. Jon-And, M. Schafer, P. Bargassa, Christopher Bee, Danilo Zavrtanik, R. Kreuger, G. Marel, Michael C. Carroll, L. Faravel, Lukas A. Schaller, T. Nakada, G. Chardin, P. Paylopoulos, G. Backenstoss, Stef. Charalambous, Nikolaos Manthos, A. Liolios, C. Thibault, B. L. Roberts, and C. Eleftheriadis
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Secondary education, Large Hadron Collider, Planck scale, CPT symmetry, Information storage, symbols.namesake, symbols, High Energy Physics::Experiment, Quantum, Research method, Coherence (physics)
Abstract: The CPLEAR experiment at CERN measures the time dependent decay rate asymmetries of initially pure K0 and K 0 states to study CP,T and CPT symmetries in the neutral kaon system. The latest results on η+−, Δm and x are reported, as well as direct tests of T violation and CPT violation in K0- K 0 oscillations. Our results are consistent with CPT invariance and allow for an improved limit on the K0- K 0 mass difference. Further, a possible loss of quantum coherence of the neutral kaon system has been tested to a level near the Planck scale.
Published: 1997
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13. The CPLEAR-Experiment at CERN

Author: Christopher Bee, Marcin Wladyslaw Wolter, G. Chardin, J. Derre, Mats Danielsson, G. Backenstoss, Ch Yèche, R. Adler, A. Go, B. Eckart, T. Schietinger, A.J.P.L. Policarpo, A. Apostolakis, T. Alhalel, M.B. Chertok, Stef. Charalambous, A. Soares, P. Fassnacht, R. Le Gac, H.-J. Gerber, L. Faravel, D. Garreta, C. Felder, J. R. Fry, K. Jon-And, P. Bargassa, G. Polivka, Lukas A. Schaller, E. Hubert, W. Fetscher, P.R. Kettle, L. Tauscher, A. Haselden, E. Machado, Ph. Schune, D. Francis, Jeffrey Boone Miller, F. Henry-Couannier, A. Ealet, T. Ruf, O. Behnke, Claudio Santoni, Andrej Filipcic, R.W. Hollander, Marc Dejardin, Nikolaos Manthos, Danilo Zavrtanik, D. Zimmerman, Claude Guyot, F. Leimgruber, P. Pavlopoulos, A. Liolios, João Carvalho, F. Montanet, A. Schopper, M. Fidecaro, P. Weber, T. Nakada, P.J. Hayman, J. Pinto Dacunha, R. Ferreira-Marques, P. Sanders, M. Mikuz, I. Papadopoulos, R. Kreuger, Panagiotis Kokkas, O. Wigger, F. Blanc, C. Kochowski, R. Gamet, Ioannis Evangelou, G. Marel, B. Pagels, L. Sakeliou, M. Schafer, Per Carlson, Michael C. Carroll, C. Thibault, B. L. Roberts, C. Eleftheriadis, E. van Beveren, Sotirios Vlachos, F. Touchard, A. Angelopoulos, Igor Mandić, A. Cody, E. Gabathuler, R. Rickenbach, V. Bertin, Elie Aslanides, C. Touramanis, Frixos A Triantis, A. Benelli, C.W.E. van Eijk, E. Cawley, and P. Bloch
Subjects: Nuclear physics, Rest (physics), Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Large Hadron Collider, High Energy Physics::Phenomenology, Measure (physics), High Energy Physics::Experiment, Atomic and Molecular Physics, and Optics
Abstract: The CPLEAR experiment uses tagged K0 and K0 produced in pp annihilation at rest to measure CP-, T- and CPT-violation parameters in the neutral kaon system. The results of these measurements and some implications are reported.
Published: 1997
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14. An upper limit for the branching ratio of the decay Ks → e+e−

Author: A. Angelopoulos, A. Apostolakis, E. Aslanides, G. Backenstoss, P. Bargassa, O. Behnke, A. Benelli, V. Bertin, F. Blanc, P. Bloch, P. Carlson, M. Carroll, J. Carvalho, E. Cawley, S. Charalambous, G. Chardin, M.B. Chertok, A. Cody, M. Danielsson, M. Dejardin, J. Derre, A. Ealet, C. Eleftheriadis, I. Evangelou, L. Faravel, R. Ferreira-Marques, W. Fetscher, M. Fidecaro, A. Filipčič, D. Francis, J. Fry, E. Gabathuler, R. Gamet, D. Garreta, H.-J. Gerber, A. Go, A. Haselden, P.J. Hayman, F. Henry-Couannier, R.W. Hollander, E. Hubert, K. Jon-And, P.-R. Kettle, P. Kokkas, R. Kreuger, R. Le Gac, F. Leimgruber, A. Liolios, E. Machado, I. Mandić, N. Manthos, G. Marel, M. Mikuž, J. Miller, F. Montanet, A. Muller, T. Nakada, B. Pagels, I. Papadopoulos, P. Pavlopoulos, J. Pinto da Cunha, A. Policarpo, G. Polivka, R. Rickenbach, B.L. Roberts, T. Ruf, L. Sakeliou, P. Sanders, M. Schäfer, L.A. Schaller, T. Schietinger, A. Schopper, A. Soares, L. Tauscher, C. Thibault, F. Touchard, C. Touramanis, F. Triantis, E. Van Beveren, C.W.E. Van Eijk, S. Vlachos, P. Weber, O. Wigger, M. Wolter, C. Yeche, D. Zavrtanik, and D. Zimmerman
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, High signal intensity, Branching fraction, CP violation, Limit (mathematics)
Abstract: A search for the decay KS → e+e− was performed within the framework of the CPLEAR experiment. Full event reconstruction together with e/π separation allowed powerful background rejection and high signal acceptance. The analysis of the complete set of data yields the result: BR(KS → e+e−) < 1.4 × 10−7 (90% CL), an improvement on the current experimental limit by a factor of 20.
Published: 1997
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15. Multinucleon pion absorption on4He into thepppnfinal state

Author: N.K. Gregory, R. P. Redwine, M. Wildi, K. Koch, A.O. Mateos, P. A. M. Gram, Miroslav Furić, H.J. Weyer, H. Ullrich, Neven Simicevic, G. Backenstoss, Urs Sennhauser, T. Dooling, J. Köhler, M. Kroedel, D. Rowntree, M. H. Wang, M.H. Wang, A. Lehmann, Darko Androić, B. Kotliński, K. Michaelian, Avraham Klein, Damir Bosnar, Mirko Planinic, H. Döbbeling, G. S. Kyle, H. Breuer, K. E. Wilson, Tomislav Petković, C. H. Q. Ingram, A. Hoffart, and R. Trezeciak
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Angular momentum, Pion, Phase space, Isospin, Absorption cross section, Neutron, Few-body systems, Atomic physics, Nucleon
Abstract: Results from a 4p solid angle measurement of the reaction p 14 He! pppn at incident pion energies of Tp15 70, 118, 162, 239, and 330 MeV are presented. Integrated cross sections are given for the reactions where three nucleons participate, leading to energetic ( ppp )o r ( ppn ) final states, and for states where four nucleons are involved ( pppn ). The two three-nucleon absorption modes were investigated in particular, and an energy dependent isospin ratio of the cross sections of s ppn /s ppp 53.661.3, 2.660.5, 1.860.3, 1.460.2, and 1.860.6 was determined from 70 to 330 MeV. The differential cross sections were described by a complete set of eight independent variables and compared to simple cascade and phase space models. From this analysis the contributions from initial state interactions to the multinucleon absorption cross sections were found to be more important at higher pion energies, while those from final state interactions are stronger at lower energies. However, both mechanisms combined were found to account for not more than one-third of the total pppn multinucleon yield. The remaining strength is reasonably well reproduced by phase space models, but shows a dependence on the incident pion’s orbital angular momentum. The isospin structure of the ( ppp ) and ( ppn ) final states is not understood, nor are some structures in their distributions. The four-nucleon yield ( pppn ) was found to be weak ~1‐8 % of the total absorption cross section! and shows no evidence for a ‘‘double-D’’ excitation. @S0556-2813~97!03210-X#
Published: 1997
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16. Upper limit for the branching ratio of KS → e+e− decay

Author: P. Bargassa, O. Behnke, Christopher Bee, Ch Yèche, B. Eckart, A. Haselden, P. Pavlopoulos, P. Sanders, F. Leimgruber, A. Schopper, Sotirios Vlachos, T. Alhalel, R. Adler, R.W. Hollander, P. Weber, A. Angelopoulos, P.J. Hayman, H.-J. Gerber, A. Go, W. Fetscher, P. Fassnacht, R. Le Gac, Panagiotis Kokkas, R. Ferreira-Marques, C. Eleftheriadis, Mats Danielsson, A. Soares, J. R. Fry, F. Henry-Couannier, C. Touramanis, J. Pinto da Cunha, E. Hubert, Ph. Schune, M. Miku, Michael C. Carroll, D. Garreta, I. Mandié, M.B. Chertok, Lukas A. Schaller, L. Faravel, T. Ruf, A. Ealet, Frixos A Triantis, K. Jon-And, Claudio Santoni, O. Wigger, Marcin Wladyslaw Wolter, J. Derre, Danilo Zavrtanik, P.R. Kettle, L. Tauscher, D. Zimmerman, D. Francis, A.J.P.L. Policarpo, A. Apostolakis, João Carvalho, F. Montanet, E. Machado, Claude Guyot, Jeffrey Boone Miller, A. Benelli, C.W.E. van Eijk, T. Nakada, Ioannis Evangelou, R. Gamet, F. Blanc, L. Sakeliou, C. Kochowski, V. Bertin, M. Schafer, Elie Aslanides, B. Pagels, R. Kreuger, Per Carlson, E. Gabathuler, R. Rickenbach, G. Marel, Marc Dejardin, P. Bloch, Nikolaos Manthos, A. Liolios, I. Papadopoulos, C. Felder, T. Schietinger, A. Filipĉič, G. Chardin, E. Cawley, M. Fidecaro, G. Backenstoss, A. Cody, C. Thibault, B. L. Roberts, E. van Beveren, F. Touchard, Stef. Charalambous, and G. Polivka
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Particle decay, Meson, Branching fraction, Quantum mechanics, Hadron, Elementary particle, Limit (mathematics), Atomic and Molecular Physics, and Optics, Calorimeter, Boson
Abstract: A measurement of the branching ratio for K s → e + e − decay was performed with the CPLEAR detector at LEAR. Full event reconstruction together with calorimeter e/π separation allowed for powerful background rejection and high signal acceptance. Analysis of data taken up to 1994 yields the result: Br(K s → e + e − ) −7 (90 % CL).
Published: 1997
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17. Experimental measurement of the ratio in antiproton annihilations at rest in gaseous hydrogen at 15 and 27 bar

Author: Ioannis Evangelou, C. Thibault, L. Sakeliou, R. Gamet, A. Soares, C. Eleftheriadis, Per Carlson, A. Cody, R. Kreuger, E. van Beveren, F. Touchard, M. Schafer, Jeffrey Boone Miller, E. Cawley, P.-R. Kettle, A. Go, Lukas A. Schaller, T. Alhalel, G. Marel, Ch Yèche, M. Mikuž, A. Muller, B. Eckart, C. Touramanis, D. Francis, Stef. Charalambous, L. Tauscher, Frixos A Triantis, H.-J. Gerber, Mats Danielsson, Ph. Schune, I. Papadopoulos, E. Machado, A. Ealet, M. Fidecaro, R. Ferreira-Marques, F. Blanc, P. Fassnacht, G. Polivka, Rr. Adler, C. Kochowski, Claudio Santoni, P. Pavlopoulos, D. Garreta, Danilo Zavrtanik, E. Hubert, T. Ruf, M.B. Chertok, B. Pagels, L. Faravel, J. Pinto da Cunha, B.L. Roberts, D. Zimmerman, João Carvalho, K. Jon-And, F. Montanet, A. Benelli, C.W.E. van Eijk, Panagiotis Kokkas, Michael C. Carroll, P. Sanders, W. Fetscher, P. Weber, Marc Dejardin, G. Chardin, Marcin Wladyslaw Wolter, J. Derre, A. Haselden, T. Nakada, R. Le Gac, G. Backenstoss, A.J.P.L. Policarpo, C. Felder, V. Bertin, A. Apostolakis, R.W. Hollander, Elie Aslanides, J. R. Fry, Sotirios Vlachos, F. Henry-Couannier, A. Angelopoulos, Andrej Filipcic, Nikolaos Manthos, A. Liolios, Claude Guyot, P. Bargassa, Christopher Bee, Igor Mandić, O. Behnke, F. Leimgruber, A. Schopper, P.J. Hayman, O. Wigger, T. Schietinger, P. Bloch, E. Gabathuler, and R. Rickenbach
Subjects: Physics, Nuclear and High Energy Physics, Annihilation, Antiproton, Gaseous hydrogen, Atomic physics
Abstract: The ratio R between the branching fractions of p p → K S K S and p p → K S K L for antiprotons annihilating at rest in gaseous hydrogen at 27 bar pressure was measured with the CPLEAR detector to be R(27 bar) = 0.037 ± 0.002. The fraction of P-wave annihilation at rest at this target density was deduced to be 0.45 ± 0.06. A value of R was also measured at 15 bar, with less statistics, yielding R(15 bar) = 0.041 ± 0.009.
Published: 1997
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18. Pion absorption on3He and4He with emission of three energetic protons

Author: A. Hoffart, B. Kotliński, A.O. Mateos, M. Wildi, D. Rowntree, H. Döbbeling, A. Lehmann, Miroslav Furić, Urs Sennhauser, H.J. Weyer, M. Kroedel, N.K. Gregory, C. H. Q. Ingram, K. E. Wilson, Avraham Klein, P. A. M. Gram, Neven Simicevic, M.H. Wang, K. Michaelian, G. Backenstoss, Damir Bosnar, R. Trezeciak, R. P. Redwine, Mirko Planinic, K. Koch, J. Köhler, Darko Androić, G. S. Kyle, H. Breuer, Tomislav Petković, M. Wang, H. Ullrich, and T. Dooling
Subjects: Physics, Nuclear physics, Nuclear and High Energy Physics, Pion, Few-body systems, Atomic physics, Absorption (electromagnetic radiation)
Published: 1997
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19. Results of CPLEAR

Author: Ioannis Evangelou, Ch Yèche, B. Eckart, L. Sakeliou, O. Behnke, Nikolaos Manthos, W. Fetscher, F. Henry-Couannier, F. Blanc, P.R. Kettle, L. Tauscher, F. Leimgruber, R. Kreuger, P. Fassnacht, A. Liolios, E. Machado, R. Gamet, A. Schopper, E. Hubert, C. Kochowski, P. Sanders, P.J. Hayman, P. Weber, Elie Aslanides, Christopher Bee, B. Pagels, G. Marel, R. Ferreira-Marques, T. Schientinger, D. Zimmerman, M. Mikuz, T. Ruf, E. van Beveren, A. Apostolakis, Claudio Santoni, P. Carlson, A.J.P.L. Policarpo, R. Le Gac, F. Touchard, Mats Danielsson, R. Adler, C. Touramanis, V. Bertin, D. Garreta, Marc Dejardin, Michael C. Carroll, Frixos A Triantis, D. Francis, I. Papadopoulos, João Carvalho, M. Schafer, F. Montanet, J. R. Fry, M.B. Chertok, A. Cody, Sotirios Vlachos, A. Go, I. Mandlic, K. Jon-And, A. Angelopoulos, Lukas A. Schaller, P. Pavlopoulos, J. Pinto da Cunha, A. Soares, A. Haselden, Jeffrey Boone Miller, E. Cawley, P. Bargassa, Ph. Schune, R.W. Hollander, Danilo Zavrtanik, A. Ealet, A. Benelli, C.W.E. van Eijk, G. Chardin, M. Fidecaro, Andrej Filipcic, C. Felder, G. Backenstoss, Claude Guyot, Panagiotis Kokkas, T. Nakada, Stef. Charalambous, G. Polivka, C. Thibault, B. L. Roberts, C. Eleftheriadis, E. Gabathuler, R. Rickenbach, L. Faravel, P. Bloch, T. Alhalel, H.-J. Gerber, O. Wigger, Marcin Wladyslaw Wolter, and J. Derre
Subjects: Nuclear physics, Rest (physics), Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Measure (physics), Atomic and Molecular Physics, and Optics
Abstract: The CPLEAR experiment uses tagged K 0 and K 0 produced in pp annihilation at rest to measure CP-, T- and CPT-violation parameters in the neutral kaon system. The results of these measurements and some implications are reported.
Published: 1997
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20. Measurement of η+− with the CPLEAR experiment

Author: C. Thibault, Andrej Filipcic, B. L. Roberts, C. Eleftheriadis, Claude Guyot, L. Faravel, M.B. Chertok, T. Ruf, Ch Yèche, B. Eckart, Claudio Santoni, K. Jon-And, J. Pinto da Cunha, Danilo Zavrtanik, P. Sanders, T. Schietinger, R. Le Gac, João Carvalho, F. Montanet, T. Alhalel, P. Bloch, M. Schafer, G. Chardin, A. Haselden, G. Backenstoss, Jeffrey Boone Miller, H.-J. Gerber, J. R. Fry, W. Fetscher, Stef. Charalambous, R.W. Hollander, G. Polivka, P.R. Kettle, L. Tauscher, O. Behnke, A. Go, Sotirios Vlachos, A. Benelli, C.W.E. van Eijk, M. Fidecaro, E. Machado, Marcin Wladyslaw Wolter, J. Derre, F. Blanc, F. Henry-Couannier, A. Soares, A. Angelopoulos, A. Apostolakis, Mats Danielsson, R. Adler, E. Gabathuler, P. Fassnacht, C. Kochowski, D. Francis, D. Garreta, Nikolaos Manthos, R. Rickenbach, F. Leimgruber, A. Schopper, A. Liolios, C. Touramanis, P.J. Hayman, T. Nakada, B. Pagels, Igor Mandić, R. Gamet, E. Hubert, C. Felder, Frixos A Triantis, P. Pavlopoulos, Christopher Bee, A.J.P.L. Policarpo, R. Ferreira-Marques, O. Wigger, M. Miku, P. Weber, D. Zimmerman, V. Bertin, Elie Aslanides, Ioannis Evangelou, Marc Dejardin, Panagiotis Kokkas, L. Sakeliou, Lukas A. Schaller, P. Bargassa, Per Carlson, R. Kreuger, I. Papadopoulos, G. Marel, Michael C. Carroll, Ph. Schune, A. Ealet, E. van Beveren, F. Touchard, A. Cody, and E. Cawley
Subjects: Systematic error, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Computer science, Statistics, Measure (mathematics), Atomic and Molecular Physics, and Optics
Abstract: The CPLEAR experiment at CERN uses time-dependent decay-rate asymmetries between K 0 and K 0 to measure η +− . The analysis and the systematic errors are discussed. The preliminary results from all our data are φ +− = 43.5 0 ± 0.5 0 stat ± 0.5 syst ± 0.4 Δm and | η +−| = (2.316 ± 0.025 stat ± 0.028 syst ± 0.009 τ S ) × 10 −3 . The dominant part in the systematic error of φ +− is due to the regeneration correction. A dedicated experiment was performed to reduce this error considerably.
Published: 1997
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21. The CPLEAR electromagnetic calorimeter

Author: Lukas A. Schaller, B. Lofstedt, W. Fetscher, L. Tauscher, P. Dechelette, U. Mall, T. Ruf, P. Gumplinger, C.P. Marin, B. Pagels, Claudio Santoni, D. Garreta, H.U. Johner, R. Adler, O. Behnke, B. Eckart, D. Guyon, G. Polivka, C. Witzig, P. Pavlopoulos, A. Schopper, M. Dröge, M. Fidecaro, C. Felder, P. Bloch, P. Petit, H. Krause, H. Tschopp, P. Weber, D. Damianoglou, Panagiotis Kokkas, F. Bal, J. Kern, G. Backenstoss, Ch. Rhême, Marcin Wladyslaw Wolter, H. Wendler, H.-J. Gerber, and F. Nanni
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Photon, Physics::Instrumentation and Detectors, Detector, Electron, Radiation length, Particle detector, Particle identification, Magnetic field, Nuclear physics, Pion, High Energy Physics::Experiment, Detectors and Experimental Techniques, Instrumentation
Abstract: A large-acceptance lead/gas sampling electromagnetic calorimeter (ECAL) was constructed for the CPLEAR experiment to detect photons from decays of $\pi^0$s with momentum $p_{\pi^0} \le 800$ MeV$/c$. The main purpose of the ECAL is to determine the decay vertex of neutral-kaon decays $\ko \rightarrow \pi^0\pi^0 \rightarrow 4 \gamma$ and $\ko \rightarrow \pi^0\pi^0\pi^0 \rightarrow 6 \gamma$. This requires a position-sensitive photon detector with high spatial granularity in $r$-, $\varphi$-, and $z$-coordinates. The ECAL --- a barrel without end-caps located inside a magnetic field of 0.44 T --- consists of 18 identical concentric layers. Each layer of $1/3$ radiation length (X${_0}$) contains a converter plate followed by small cross-section high-gain tubes of 2640 mm active length which are sandwiched by passive pick-up strip plates. The ECAL, with a total of $6$ X${_0}$, has an energy resolution of $\sigma (E)/E \approx 13\% / \sqrt{E(\mathrm{GeV})}$ and a position resolution of 4.5 mm for the shower foot. The shower topology allows separation of electrons from pions. The design, construction, read-out electronics, and performance of the detector are described.
Published: 1997
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22. The CPLEAR detector at CERN

Author: K. Philippoussis, H. Verweij, G. Backenstoss, P. Bloch, G. Kesseler, A. Haselden, Andrej Filipcic, P. Pavlopoulos, F. Louis, D. Damianoglou, E. Rozaki, Panagiotis Kokkas, Dominique Durand, P.-R. Kettle, M. Bonnet, F. Bal, H.U. Johner, Claude Guyot, M. Steinacher, P. Petit, T. Alhalel, R.W. Hollander, Andras Kerek, Ch Yèche, D.A. Troster, L. Faravel, M. Mikuž, D. Francis, O. Behnke, B. Eckart, Sp. Dedoussis, J. Duclos, K. Sarigiannis, C. Engster, J.P. Bard, E. Gabathuler, M. Dedieu, R. Rickenbach, T. Ruf, Mats Danielsson, R. Adler, N. Dudragne, C. Jacobs, C.P. Marin, P. Weber, Ph. Schune, E. Machado, M. Schafer, V. Bertin, P.F. Harrison, H.-J. Gerber, F. Leimgruber, A. Schopper, K. Jansson, H. Martin, Christopher Bee, L. Sacks, Ioannis Evangelou, W.G. Heyes, P. Gumplinger, M. Dodgson, R. Le Gac, A. Ealet, T. Nakada, H. Postma, E. Hazen, L. Sakeliou, R. Daniel, Ch. Bula, E. Aslanides, Nikolaos Manthos, P Harrison, P.J. Hayman, W. Albrecht, F. Nanni, M. Chardalas, Per Carlson, H. Tschopp, M.B. Chertok, A. Liolios, D. Lecouturier, Ch. Rhême, D. Garreta, J.C. Michau, W. Fetscher, C. Witzig, J. R. Fry, M. Fidecaro, P. Fassnacht, A. Benelli, C.W.E. van Eijk, Christer Fuglesang, G. S. Varner, A. Go, E. Hubert, M. Dröge, K. Jon-And, S. Tatsis, Claudio Santoni, Marc Dejardin, B.L. Roberts, Lukas A. Schaller, A. Calzas, F. Blanc, U. Mall, D. King, R. Gamet, C. Touramanis, T. Geralis, D. Guyon, C. Kochowski, N. Karkour, D. Zimmerman, T. Klados, Frixos A Triantis, Danilo Zavrtanik, F. Henry-Couannier, C. Felder, D. Barraca, B. Pagels, A. Soares, D. Linget, João Carvalho, F. Montanet, L. Tauscher, P. Dechelette, P. Tsilimigras, B. Lofstedt, K. Kontek, Marcin Wladyslaw Wolter, P. Sanders, I. Papadopoulos, J. Derre, F. Pelucchi, P. Maley, O. Wigger, B. van Koningsveld, Jeffrey Boone Miller, A.J.P.L. Policarpo, D. Geiss, T. Lawry, H. Wendler, G. Chardin, Jean-Louis Faure, J. Kern, C. Thibault, C. Eleftheriadis, Stef. Charalambous, D. Warner, G. Polivka, Michael C. Carroll, R. Kreuger, A. Apostolakis, G. Marel, I. Tsamouranis, P. Charra, Sotirios Vlachos, A. Angelopoulos, J. Pinto da Cunha, A. Onofre, T. Schietinger, J. Bennet, Igor Mandić, A. Dijksman, J.P. Vanuxem, Y. Gally, R. Ferreira-Marques, E. van Beveren, F. Touchard, J. A. P. Da Silva, A. Cody, B. Dinkespiller, E. Cawley, E. Watson, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), CPLEAR, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Lorgeril, Jocelyne
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Large Hadron Collider, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, Cherenkov detector, Detector, Tracking (particle physics), 7. Clean energy, 01 natural sciences, Particle identification, law.invention, Nuclear physics, Time of flight, law, Antiproton, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Detectors and Experimental Techniques, 010306 general physics, Instrumentation
Abstract: The CPLEAR collaboration has constructed a detector at CERN for an extensive programme of CP-, T- and CPT-symmetry studies using ${\rm K}^0$ and $\bar{\rm K}^0$ produced by the annihilation of $\bar{\rm p}$'s in a hydrogen gas target. The ${\rm K}^0$ and $\bar{\rm K}^0$ are identified by their companion products of the annihilation ${\rm K}^{\pm} \pi^{\mp}$ which are tracked with multiwire proportional chambers, drift chambers and streamer tubes. Particle identification is carried out with a liquid Cherenkov detector for fast separation of pions and kaons and with scintillators which allow the measurement of time of flight and energy loss. Photons are measured with a lead/gas sampling electromagnetic calorimeter. The required antiproton annihilation modes are selected by fast online processors using the tracking chamber and particle identification information. All the detectors are mounted in a 0.44 T uniform field of an axial solenoid of diameter 2 m and length 3.6 m to form a magnetic spectrometer capable of full on-line reconstruction and selection of events. The design, operating parameters and performance of the sub-detectors are described.}
Published: 1996
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23. Contribution of initial state interactions to the three-nucleon absorption of pions by 3He

Author: N.K. Gregory, Miroslav Furić, H. Breuer, D. Rowntree, G. S. Kyle, A.O. Mateos, B. Kotliński, R. Trezeciak, M. Wildi, H.J. Weyer, N. Šimičević, R.P. Redwine, T. Dooling, H. Ullrich, C. H. Q. Ingram, K. Koch, M. H. Wang, H. Döbbeling, M.H. Wang, K. E. Wilson, P. A. M. Gram, A. Lehmann, Tomislav Petković, G. Backenstoss, Avraham Klein, U. Sennhauser, A. Hoffart, J. Köhler, M. Kroedel, K. Michaelian, and Damir Bosnar
Subjects: Physics, Nuclear and High Energy Physics, SIMPLE (dark matter experiment), Cross section (physics), Pion, Nuclear Theory, Absorption cross section, State (functional analysis), Atomic physics, Nuclear Experiment, Absorption (electromagnetic radiation), Nucleon
Abstract: The distributions of protons after the absorption of positive pions by 3 He at 118, 162 and 239 MeV are presented. A decomposition of the three-nucleon cross section in terms of initial state interactions and other processes is given, based upon simple models. A clear signal of initial state interactions is visible in the data, diminishing at the lower energies.
Published: 1996
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24. Measurement ofCP violation parameters and test ofCPT invariance with$$\overline {K^0 } $$ and K0 at LEARand K0 at LEAR

Author: Lukas A. Schaller, Danilo Zavrtanik, R. Le Gac, L. Tauscher, E. Machado, Nikolaos Manthos, A. Liolios, L. Faravel, P. R. Kettle, F. Blanc, Marc Dejardin, P. Sanders, A. Go, Sp. Dedoussis, A.J.P.L. Policarpo, C. Kochowski, J. R. Fry, W. Fetscher, A. Cody, Ph. Schune, G. S. Varner, A. Ealet, M. Schafer, J. Duclos, B. Pagels, E. Rozaki, R. Kreuger, A. Haselden, C. Thibault, I. Papadopoulos, G. Marel, T. Nakada, P. Pavlopoulos, B. L. Roberts, V. Bertin, C. Felder, Claudio Santoni, Andrej Filipcic, Elie Aslanides, C. Eleftheriadis, R.W. Hollander, Michael C. Carroll, João Carvalho, F. Montanet, Mats Danielsson, R. Adler, P. Weber, F. Henry-Couannier, Claude Guyot, A. Apostolakis, O. Wigger, O. Behnke, D. Garreta, F. Leimgruber, Ch Yèche, E. van Beveren, B. Eckart, F. Touchard, Frixos A Triantis, P.J. Hayman, E. Cawley, R. Gamet, Stef. Charalambous, T. Ruf, Marko Mikuz, Marcin Wladyslaw Wolter, J. Derre, G. Polivka, A. Benelli, C.W.E. van Eijk, R. Ferreira-Marques, Ioannis Evangelou, Ch. Bula, L. Sakeliou, J. Pinto da Cunha, M. Fidecaro, Per Carlson, G. Chardin, Jean-Louis Faure, G. Backenstoss, K. Sarigiannis, P. Fassnacht, Panagiotis Kokkas, A. Onofre, Igor Mandić, Christopher Bee, D. Francis, E. Hubert, T. Alhalel, A. Schopper, E. Gabathuler, R. Rickenbach, H.-J. Gerber, Sotirios Vlachos, D. Zimmerman, A. Angelopoulos, M. Chardalas, M.B. Chertok, K. Jon-And, A. Soares, C. Touramanis, Jeffrey Boone Miller, and P. Bloch
Subjects: Physics, Nuclear physics, Particle physics, Large Hadron Collider, Overline, Homogeneous space, Parity (physics), General Agricultural and Biological Sciences
Abstract: The CPLEAR experiment at CERN studies theCP, T andCPT symmetries in the neutral-kaon system by measuring the rate asymmetries between the decays of initially pure K0 and $$\overline {K^0 } $$ states. Using data taken between 1990 and mid 1994, precise measurements of |η+-|,φ +- and Δm are reported. The comparison of φ+- the superweak phase gives one of the most sensitive tests ofCPT invariance and leads to a new limit on the $$K^0 - \overline {K^0 } $$ mass difference.
Published: 1996
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25. Observation of the CP-conserving Ks → π+π−π0 decay amplitude

Author: L. Faravel, P. Carlson, W. Fetscher, H. Postma, F. Henry-Couannier, O. Behnke, D. Garreta, M. Mikuž, L. Sacks, F. Leimgruber, Ioannis Evangelou, A. Schopper, D. Francis, C. Witzig, J. Duclos, R. Ferreira-Marques, Mats Danielsson, R. Adler, P.J. Hayman, P.F. Harrison, Andrej Filipcic, J. Derre, P.-R. Kettle, H.U. Johner, E. Gabathuler, R. Rickenbach, P. Gumplinger, Ch Yèche, Stef. Charalambous, B. Eckart, O. Wigger, L. Tauscher, L. Sakeliou, C. Touramanis, R. Le Gac, Claude Guyot, F. Blanc, T. Ruf, E. Machado, J. K. Bienlein, Frixos A Triantis, R. Gamet, Philippe Bloch, P. Pavlopoulos, Ph. Schune, G. Polivka, C. Kochowski, E. Aslanides, L.A. Schaller, Panagiotis Kokkas, K. Jansson, A. Ealet, T. Geralis, B.L. Roberts, M. Chardalas, M.B. Chertok, B. Pagels, Sotirios Vlachos, Danilo Zavrtanik, K. Jon-And, A. Angelopoulos, Claudio Santoni, G. Backenstoss, P. Fassnacht, R. Kreuger, A. Haselden, J. R. Fry, J. Pinto da Cunha, E. Rozaki, E. Hubert, A. Benelli, C.W.E. van Eijk, D.A. Troster, Sp. Dedoussis, Marcin Wladyslaw Wolter, F. Pelucchi, João Carvalho, F. Montanet, D. Zimmerman, Jeffrey Boone Miller, G. S. Varner, R.W. Hollander, C. Fuglesang, A. Onofre, M. Schafer, T. Lawry, Nikolaos Manthos, C. Felder, T. Alhalel, V. Bertin, T. Schietinger, Ch. Bula, M. Dodgson, A. Go, H.-J. Gerber, W.G. Heyes, A. Soares, A. Liolios, G. Chardin, Jean-Louis Faure, M. Fidecaro, A. Apostolakis, J. Bennet, I. Papadopoulos, C. Thibault, P. Maley, G. Marel, T. Nakada, P. Sanders, C. Eleftheriadis, Igor Mandić, A.J.P.L. Policarpo, P. Weber, Marc Dejardin, Michael C. Carroll, Christopher Bee, A. Cody, K. Sarigiannis, E. Cawley, E. van Beveren, and F. Touchard
Subjects: Physics, Nuclear and High Energy Physics, Amplitude, Branching fraction, Quantum mechanics, Phase space, Zero (complex analysis), Atomic physics, Interference (wave propagation)
Abstract: The interference between CP-conserving Ks and K L → π + π − π 0 decay amplitudes was observed by studying the decay rate asymmetries between initial K 0 and K 0 separately for the phase space regions E CM ( π + ) > E CM ( π − ) and E CM ( π + ) E CM ( π − ). For the parameter λ we found Re(λ) = 0.036 ± 0.010(stat.) −0.003 +0.002 (syst.) and Im(λ) consistent with zero, leading to a branching ratio B = [4.1 −1.9 +2.5 (stat.) −0.6 +0.5 (syst.)] × 10 −7 for the CP-conserving K S → π + π − π 0 decay.
Published: 1996
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26. A Large Acceptance Detector System (LADS) for studies of pion absorption

Author: G. van der Steenhoven, A.O. Mateos, Mirko Planinic, D. R. Tieger, Darko Androić, Tomislav Petković, C. H. Q. Ingram, M. Kroedel, S. Mukhopadhyay, N. Šimičević, A. Lehmann, H. Döbbeling, B. Kotliński, H. Breuer, A. Brkovic, Damir Bosnar, Z. N. Lin, A. Hoffart, J. P. Haas, W. Fong, G. Backenstoss, G. S. Kyle, G. Mahl, H.J. Weyer, K. Michaelian, M. H. Wang, T. Alteholz, K. Koch, Miroslav Furić, H. Ullrich, M.H. Wang, M. Wildi, P. A. M. Gram, K. E. Wilson, J. Köhler, R.P. Redwine, D. Rowntree, R. A. Schumacher, T. Dooling, F.D. Smit, Avraham Klein, U. Sennhauser, R. Trezeciak, and N.K. Gregory
Subjects: Physics, Nuclear and High Energy Physics, Physics::Instrumentation and Detectors, business.industry, Detector, Solid angle, Scintillator, Nuclear physics, Optics, Pion, Phase space, Cylinder, Nuclear Experiment, Absorption (electromagnetic radiation), business, Instrumentation
Abstract: A Large Acceptance Detector System (LADS) has been designed and built at the Paul Scherrer Institute to study multiparticle final states following pion-nucleus absorption. It consists of a 28-sector cylinder of plastic scintillators of 1.6 m active length and 1.4 m diameter, two cylindrical wire chambers, and two 14-sector plastic scintillator end-caps which close each end. The nearly 4π solid angle coverage of this detector minimizes uncertainties associated with extrapolations over unmeasured regions of phase space. The design and the performance of the LADS detector are presented.
Published: 1996
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27. Evidence for pion absorption on four nucleons

Author: H.J. Weyer, Tomislav Petković, M. Wildi, M. Džemidžić, Miroslav Furić, B. Rzehorz, G. Backenstoss, D. Weiser, H. Ullrich, and A. Hoffart
Subjects: Nuclear physics, Physics, Pion, Coincident, Nuclear Theory, Four nucleons pion absorption, General Physics and Astronomy, Atomic physics, Nuclear Experiment, Nucleon, Absorption (electromagnetic radiation), Spectral line
Abstract: Experimental spectra from the coincident detection of three nucleons after the pion absorption in 4He are displayed. The presence of a mechanism with four nucleons participating in the absorption process is made obvious. The total cross-sections for this absorption mode are: σabs4NA = (1.0 ± 0.2) mb at Tπ = 120 MeV and σabs4NA = (2.18 ± 0.65) mb at Tπ = 210 MeV .
Published: 1996
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28. Evaluation of the phase of the CP violation parameter η+− and the KL - KS mass difference from a correlation analysis of different experiments

Author: Ch Yèche, B. Eckart, M. Mikuž, D. Francis, Igor Mandić, J. Derre, P. Fassnacht, C. Touramanis, E. van Beveren, F. Touchard, Frixos A Triantis, R. Gamet, L.A. Schaller, A. Haselden, O. Wigger, R. Ferreira-Marques, Christopher Bee, J. Pinto da Cunha, P. Carlson, W. Fetscher, E. Hubert, A. Cody, T. Schietinger, R.W. Hollander, L. Tauscher, C. Felder, F. Henry-Couannier, V. Bertin, Andrej Filipcic, D. Garreta, E. Machado, D. Zimmerman, Claudio Santoni, Ph. Schune, Jeffrey Boone Miller, Mats Danielsson, R. Adler, T. Nakada, Claude Guyot, A. Ealet, Michael C. Carroll, T. Ruf, L. Faravel, João Carvalho, A. Benelli, C.W.E. van Eijk, M.B. Chertok, E. Cawley, F. Montanet, K. Jon-And, P. Pavlopoulos, Marcin Wladyslaw Wolter, Danilo Zavrtanik, G. Backenstoss, G. Chardin, F. Blanc, O. Behnke, E. Gabathuler, R. Rickenbach, P.-R. Kettle, C. Kochowski, Panagiotis Kokkas, Ioannis Evangelou, F. Leimgruber, A. Schopper, B. Pagels, A. Go, R. Kreuger, L. Sakeliou, Marc Dejardin, P.J. Hayman, Nikolaos Manthos, A. Soares, A. Apostolakis, G. Marel, Sotirios Vlachos, A. Liolios, C. Thibault, B.L. Roberts, P. Sanders, A. Angelopoulos, M. Fidecaro, C. Eleftheriadis, A.J.P.L. Policarpo, H.-J. Gerber, I. Papadopoulos, Stef. Charalambous, G. Polivka, M. Schafer, P. Weber, R. Le Gac, E. Aslanides, J. R. Fry, G. S. Varner, and Philippe Bloch
Subjects: Physics, Nuclear and High Energy Physics, Quantum mechanics, Phase (matter), Correlation analysis, Analytical chemistry, CP violation
Abstract: The best estimation of ϕ +− (the phase of the CP violation parameter η +− ) and of Δm (the K L - K S mass difference) is obtained by averaging the results of different experiments, taking into account the different correlation, existing for most of the experiments, between the measurement of ϕ +− and Δm . Including the recent measurements, we obtain the average values 〈Δm〉 = (530.7 ± 1.3) × 10 7 ħ/s and 〈 ϕ +− 〉 = 43.82° ± 0.63°. This value of ϕ +− is in good agreement with the superweak phase ϕ SW = 43.49° ± 0.08°.
Published: 1996
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29. Measurement of the CP violation parameter η+− using tagged K0 and 0

Author: M. Chardalas, M.B. Chertok, K. Jon-And, T. Alhalel, R. Le Gac, M. Schafer, A. Haselden, C. Thibault, J. Bennet, Andrej Filipcic, R.W. Hollander, Claudio Santoni, C. Felder, P. Carlson, Mats Danielsson, R. Adler, W. Fetscher, T. Nakada, Igor Mandić, R. Ferreira-Marques, E. Cawley, C. Eleftheriadis, E. Aslanides, J. R. Fry, João Carvalho, F. Montanet, H.U. Johner, Claude Guyot, P.F. Harrison, H.-J. Gerber, F. Henry-Couannier, W.G. Heyes, G. S. Varner, P.-R. Kettle, V. Bertin, L. Tauscher, Ch Yèche, B. Eckart, O. Wigger, L. Faravel, P. Sanders, E. Machado, J. Derre, Panagiotis Kokkas, D. Garreta, G. Policarpo, D. Gamet, Stef. Charalambous, C. Touramanis, J. K. Bienlein, Nikolaos Manthos, B.L. Roberts, Ch. Bula, Frixos A Triantis, O. Behnke, A. Liolios, A. Cody, L. Sacks, Philippe Bloch, M. Dodgson, Marc Dejardin, F. Leimgruber, Sp. Dedoussis, G. Polivka, Sotirios Vlachos, A. Schopper, M. Fidecaro, T. Schietinger, H. Postma, T. Geralis, A. Benelli, C.W.E. van Eijk, P.J. Hayman, Danilo Zavrtanik, A. Go, A. Angelopoulos, Ph. Schune, G. Backenstoss, Marcin Wladyslaw Wolter, J. Pinto da Cunha, I. Papadopoulos, P. Weber, A. Ealet, F. Pelucchi, T. Lawry, J. Duclos, E. van Beveren, F. Touchard, P. Maley, A. Soares, M. Mikuž, D. Francis, P. Pavlopoulos, A. Onofre, T. Ruf, R. Gamet, K. Jansson, G. Chardin, Jean-Louis Faure, L.A. Schaller, E. Rozaki, C. Witzig, K. Sarigiannis, F. Blanc, C. Kochowski, Christopher Bee, B. Pagels, Jeffrey Boone Miller, C. Fuglesang, Ioannis Evangelou, R. Kreuger, E. Gabathuler, R. Rickenbach, P. Gumplinger, A. Apostolakis, G. Marel, L. Sakeliou, Michael C. Carroll, P. Fassnacht, E. Hubert, D. Zimmerman, and D.A. Troster
Subjects: Nuclear physics, Physics, Semileptonic decay, Nuclear and High Energy Physics, media_common.quotation_subject, CP violation, Asymmetry, media_common
Abstract: The CP violation parameter η+− is determined through the eigentime-dependent asymmetry in the rates of initially tagged K0 and K 0 decaying to π+π−. The obtained values are |η+−| = (2.312 ± 0.043stat. ± 0.030syst. ± 0.011τs) × 10−3 and Φ+− = 42.7° ± 0.9stat.° ± 0.6syst.° ± 0.9Δm° with Δ = (527.4 ± 2.9) × 10 7 h gs −1 measured in the same experiment using the semileptonic decay channel.
Published: 1995
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30. Pion absorption at rest in 4He

Author: D. Gotta, H.J. Weyer, Miroslav Furić, H. Ullrich, P. Weber, G. Backenstoss, S. Vinzelberg, Tomislav Petković, and E. Daum
Subjects: Rest (physics), Physics, Nuclear reaction, Nuclear and High Energy Physics, Nuclear Theory, Coincidence, Nuclear physics, Pion, Deuterium, Isospin, Atomic physics, Nuclear Experiment, Nucleon, Absorption (electromagnetic radiation)
Abstract: The emission of nn-, np-, nd- and nt-pairs following π − -capture in gaseous 4 He has been studied in a coincidence experiment. Quasifree 2N-absorption is the dominant absorption mechanism with a ratio of r = 4.0 −1.5 +0.8 for absorption on a nucleon pair with isospin I = 0 and I = 1. Also collinear processes involving more than two nucleons have been observed, including NN final-state interaction with small relative momenta as well as emission of deuterons and tritons. Upper limits are given for phase-space-distributed, i.e. non-collinear 3N- and nnd-emission.
Published: 1995
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31. Inclusive measurement of $$\bar p$$ annihilation at rest in gaseous hydrogen to final states containingρ andf 2

Author: R. Le Gac, E. Aslanides, J. R. Fry, P. Bloch, G. S. Varner, P. Sanders, J.C. Dousse, T. Alhalel, Christopher Bee, Mats Danielsson, R. Adler, A. Haselden, Ioannis Evangelou, O. Wigger, R.W. Hollander, M. Chardalas, M.B. Chertok, K. Jon-And, P. Gumplinger, L. Sakeliou, A.J.P.L. Policarpo, L. Faravel, H.-J. Gerber, Jeffrey Boone Miller, Stef. Charalambous, Per Carlson, T. Nakada, W. Fetscher, J. K. Bienlein, K. Sarigiannis, E. Gabathuler, L. Sacks, R. Richkenbach, D.A. Troster, W.G. Heyes, C.W.E. van Eijk, G. Polivka, A. Go, H. Postma, Christer Fuglesang, R. Gamet, Nikolaos Manthos, P. Fassnacht, Sp. Dedoussis, Ch. Bula, M. Schafer, A. Liolios, Lukas A. Schaller, P. Pavlopoulos, F. Henry-Couannier, A. Soares, C. Touramanis, Marcin Wladyslaw Wolter, C. Witzig, P. Weber, J. Bennet, J. Derre, M. Fidecaro, P. F. Harrisch, F. Pelucchi, Frixos A Triantis, B. Eckart, A. Angelopoulos, J. Pinto da Cunha, D. Zimmerman, C. Thibault, O. Behnke, C. Kochowski, T. Lawry, M. Mikuž, D. Francis, T. Geralis, B. L. Roberts, Danilo Zavrtanik, B. Pagels, C. Eleftheriadis, A. Schopper, R. Ferreira-Marques, P. Maley, Andras Kerek, P.J. Hayman, Igor Mandić, Francois Touchard, A. Onofre, Panagiotis Kokkas, C. Felder, C. Yeche, V. Bertin, P.R. Kettle, L. Tauscher, G. Chardin, Jean-Louis Faure, E. Machado, D. Garreta, J. Kern, G. Backenstoss, R. Kreuger, A. Apostolakis, Andrej Filipcic, H.U. Johner, Claude Guyot, A. Cody, S. Vlachos, G. Marel, E. Cawley, J. Duclos, T. Ruf, K. Jansson, E. van Beveren, Marc Dejardin, E. Rozaki, M. Dodgson, Claudio Santoni, João Carvalho, F. Montanet, Ph. Schune, and A. Ealet
Subjects: Physics, Annihilation, Physics and Astronomy (miscellaneous), Hydrogen, Meson, Gaseous hydrogen, chemistry.chemical_element, Elementary particle, Nuclear physics, chemistry, Antiproton, Quantum field theory, Atomic physics, Engineering (miscellaneous)
Abstract: Antiproton annihilation at rest in gaseous hydrogen (16 bar pressure) to the final states ρ(770)X andf2(1270)X, whereX stands for one or more neutral mesons, has been studied at LEAR using the CPLEAR detector. Relative branching ratios are given forX =π0,2π0, 3π0 ω in the ρ case, and forX =π0, η in thef2 case. The annihilation channel$\bar pp \to \rho 3\pi ^0 $ has not been measured before. The fraction of P-wave annihilation is deduced from the ratiof2π0/ρπ0 to be 0.38±0.07, in good agreement with the result previously obtained by CPLEAR from the ratioK+K-/π+π-.
Published: 1995
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32. Negative pion absorption at rest inHe3

Author: M. Dörr, G. Schmidt, D. Gotta, P. Weber, W. Kowald, M. Izycki, I. Schwanner, W. Fetscher, H.J. Weyer, G. Backenstoss, and H. Ullrich
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Pion, Hodoscope, Phase space, Isoscalar, Nuclear Theory, Absorption (logic), State (functional analysis), Atomic physics, Nuclear Experiment, Nucleon
Abstract: The pnn and dn final states after the absorption of stopped pions in $^{3}\mathrm{He}$ have been measured in a kinematically complete experiment covering the whole phase space. Proton-neutron, deuteron-neutron, and neutron-neutron coincidences have been detected with a charged-particle hodoscope and large-area time-of-flight counters. For the first time, triple coincidences between the pionic K x rays and two particles have been measured thus selecting absorption from the atomic 1s state. It has been found that the absorption is dominated by the two-nucleon mechanism (2NA) on isoscalar nucleon pairs as indicted by the measured ratio of 6.3\ifmmode\pm\else\textpm\fi{}1.1 for back-to-back correlated nn and pn pairs. A substantial amount of the three-body final state pnn is affected by the final-state interaction (FSI) or leads to the two-particle final state dn. Ratios of 3.1\ifmmode\pm\else\textpm\fi{}0.4 for 2NA to FSI and of 4.2\ifmmode\pm\else\textpm\fi{}0.6 for the pnn to the dn final state are measured. No evidence has been found for three-nucleon absorption with an upper limit of %/${\mathrm{\ensuremath{\pi}}}_{\mathrm{stop}}^{\mathrm{\ensuremath{-}}}$.
Published: 1995
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33. Bose-Einstein correlations in $$\bar p$$ p annihilations at rest

Author: P. Fassnacht, P. Sanders, A.J.P.L. Policarpo, Claudio Santoni, O. Behnke, K. Jon-And, A. Schopper, A. Haselden, P.J. Hayman, Jeffrey Boone Miller, M. Mikuž, D. Francis, L. Faravel, K. Sarigiannis, João Carvalho, F. Montanet, D. Zimmerman, C. Touramanis, E. van Beveren, R.W. Hollander, E. Rozaki, Christopher Bee, P. Weber, R. Gamet, B. Eckart, Frixos A Triantis, L. Tauscher, R. Le Gac, F. Touchard, Andras Kerek, E. Machado, L.A. Schaller, E. Aslanides, T. Nakada, L. Sacks, H. Postma, C. Fuglesang, T. Geralis, A. Apostolakis, J. Bennet, R. Kreuger, J. Duclos, T. Ruf, Igor Mandić, M. Dodgson, J. R. Fry, G. S. Varner, Danilo Zavrtanik, K. Jansson, A. Cody, Philippe Bloch, Ioannis Evangelou, P. Carlson, W. Fetscher, P. Gumplinger, L. Sakeliou, P. Maley, Sp. Dedoussis, S. Vlachos, C. Felder, D.A. Troster, C. Witzig, C. Yeche, M. Chardalas, G. Marel, F. Henry-Couannier, M.B. Chertok, M. Schafer, E. Cawley, C.W.E. van Eijk, P. Pavlopoulos, Marc Dejardin, V. Bertin, R. Ferreira-Marques, Mats Danielsson, R. Adler, P.F. Harrison, Ph. Schune, A. Ealet, C. Kochowski, B. Pagels, A. Go, Andrej Filipcic, H.U. Johner, Claude Guyot, A. Soares, C. Thibault, C. Eleftheriadis, G. Chardin, Jean-Louis Faure, D. Garreta, J. Kern, G. Backenstoss, Ch. Bula, M. Fidecaro, Panagiotis Kokkas, Stef. Charalambous, G. Polivka, P.-R. Kettle, Nikolaos Manthos, A. Liolios, Marcin Wladyslaw Wolter, J. Derre, F. Pelucchi, A. Angelopoulos, T. Lawry, E. Gabathuler, R. Rickenbach, J.C. Dousse, T. Alhalel, J. Pinto da Cunha, H.-J. Gerber, A. Onofre, W.G. Heyes, O. Wigger, J. K. Bienlein, and B.L. Roberts
Subjects: Physics, Nuclear physics, Correlation function (statistical mechanics), Particle physics, Pion, Physics and Astronomy (miscellaneous), Antiproton, Symmetrization, Elementary particle, Bose–Einstein correlations, Wave function, Engineering (miscellaneous), Exponential function
Abstract: Two-charged-pion correlations were studied in$\bar p$p(→2π*2π−nπ0,n≥0) annihilations at rest with the CPLEAR detector at the Low-Energy Antiproton Ring (LEAR). A strong enhancement was found in the production of pairs of like-sign pions with a small value of the relative fourmomentumQ, with respect to pairs of unlike-sign pions. The observed enhancement was interpreted as a consequence of the Bose-Einstein symmetrization of the two-pion wave function. The data are well represented by a correlation function parametrized as a double-Gaussian; an exponential parametrization is also statistically acceptable. The value of the correlation strength is found to be >1. The high-quality large data samples together with the ability for K± identification and final-state separation allowed the study of systematic effects impacting on theQ dependence of the correlation function and on the extracted space parameters of the pion sources.
Published: 1994
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34. Large-Solid-Angle Study of Pion Absorption onHe3

Author: J. P. Haas, J. Köhler, B. Kotliński, A.O. Mateos, M. Wildi, C.H.Quentin Ingram, R. Trezeciak, F.D. Smit, P. A. M. Gram, S. Mukhopadhyay, Urs Sennhauser, Miroslav Furić, Tomislav Petković, W. Fong, M. H. Wang, Z. N. Lin, M.H. Wang, R. A. Schumacher, D. R. Tieger, M. Kroedel, H. Döbbeling, Damir Bosnar, Neven Simicevic, D. Rowntree, G. Backenstoss, H. Ullrich, T. Alteholz, Darko Androić, G. Mahl, Avraham Klein, H.J. Weyer, H. Breuer, A. Lehmann, G. van der Steenhoven, G. S. Kyle, A. Brkovic, R. P. Redwine, K. Koch, T. Dooling, N.K. Gregory, A. Hoffart, K. E. Wilson, and K. Michaelian
Subjects: Physics, Nuclear physics, Nuclear reaction, Cross section (physics), Pion, Hadron, Absorption cross section, Solid angle, General Physics and Astronomy, Atomic physics, Nucleon, Absorption (electromagnetic radiation)
Abstract: Measurements have been made of [pi][sup +] absorption on [sup 3]He at [ital T][sub [pi]][sup +]=118, 162, and 239 MeV using the Large Acceptance Detector System. The nearly 4[pi] solid angle coverage of this detector minimizes uncertainties associated with extrapolations over unmeasured regions of phase space. The total absorption cross section is reported. In addition, the total cross section is divided into components in which only two or all three nucleons play a significant role in the process. These are the first direct measurements of the total and three nucleon absorption cross sections.
Published: 1994
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35. Two pion Bose-Einstein correlations in p annihilations at rest

Author: G. Chardin, Jean-Louis Faure, D. Garreta, J. Kern, G. Backenstoss, C. Thibault, C. Eleftheriadis, Ch Yèche, Francois Touchard, B. Eckart, Stef. Charalambous, Christer Fuglesang, G. Polivka, J. Pinto da Cunha, H. Postma, K. Sarigiannis, Sp. Dedoussis, R. Le Gac, J. R. Fry, P. Gumplinger, Andras Kerek, J. Duclos, M. Dejardin, A. Go, Ph. Schune, M. Schafer, T. Ruf, M. Chardalas, A. Onofre, A. Soares, R. Kreuger, A. Ealet, Kerstin Jon-And, Christopher Bee, K. Jansson, Nikolaos Manthos, P. Pavlopoulos, Ioannis Evangelou, G. S. Varner, A. Liolios, A. Schopper, B.L. Roberts, P.J. Hayman, J.P. Miller, E. van Beveren, T. Nakada, R. Garnet, Ch. Bula, P.R. Kettle, L. Tauscher, C. Witzig, V. Bertin, W. Fetscher, E. Machado, O. Wigger, Elie Aslanides, J. K. Bienlein, M. Fidecaro, M. Van den Putte, A. Alhalel, J.C. Dousse, P. Fassnacht, S. Vlachos, O. Wolter, G. Marel, J. Bennet, E. Cawley, Marko Mikuz, A. Apostolakis, Mats Danielsson, D.A. Troester, H.-J. Gerber, R. Adler, Igor Mandić, Danilo Zavrtanik, E. Gabathuler, R. Rickenbach, D. Zimmerman, E. Rozaki, W.G. Heyes, C. Kochowski, P. Carlson, R. Ferreira-Marques, B. Pagels, David Francis, C.W.E. van Eijk, P. Sanders, S. Szilagyi, Theodoros Geralis, A. Angelopoulos, P.F. Harrison, A.J.P.L. Policarpo, P. Bloch, J. Derre, Panagiotis Kokkas, F. Pelucchi, P. Weber, C. Touramanis, R.W. Hollander, Frixos A Triantis, T. Lawry, L.A. Schaller, Claudio Santoni, Andrej Filipcic, H.U. Johner, João Carvalho, F. Montanet, Claude Guyot, C. Felder, M. Dodgson, P. Maley, L. Sakeliou, L. Faravel, and L. Sacks
Subjects: Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Pion, Large Hadron Collider, Nuclear Theory, Detector, High Energy Physics::Experiment, Bose–Einstein correlations, Multiplicity (chemistry), Nuclear Experiment
Abstract: Bose-Einstein (BE) correlations between like-sign charged pions were studied in pp annihilations at rest into four-prong events, using data taken with the CPLEAR detector at LEAR (CERN). A strong enhancement was found in the production of pairs of like-sign pions of similar momenta, with respect to the pairs of unlike-sign pions. The observed BE- enhancement was used to extract the values for the strength λ of the effect and the radius r of the pion emitting source. The extracted value of λ >l is of relevant importance and clearly does not depend on the assumed parametrization of the correlation function. The influence of the normalization and fitting procedure, the detector resolution, the resonances production and decay and the neutral-pion multiplicity cuts, on the size of the pion source and the strength of the effect was investigated.
Published: 1993
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36. Experiments with exotic atoms

Author: G. Backenstoss
Subjects: Physics, General Physics and Astronomy, Atomic physics, Exotic atom
Published: 1993
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37. Pion absorption in tritium at intermediate energies

Author: H. Ullrich, R. H. Sherman, H. Zmeskal, H.J. Weyer, H. Krause, Miroslav Furić, A. Janett, M. Wildi, Neven Simicevic, G. Backenstoss, P. Salvisberg, R.J. Powers, A. Hoffart, Tomislav Petković, M. Steinacher, B. Rzehorz, and Damir Bosnar
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Isovector, Proton, Nuclear Theory, Pion absorption in tritium, Nuclear physics, Pion, Isospin, Neutron, Absorption (logic), Atomic physics, Nuclear Experiment, Nucleon
Abstract: The angular distribution of nucleons from a kinematically complete measurement of pions absorbed in {sup 3}H on nucleon pairs with isospin {ital T}=0 and {ital T}=1 at incident pion energies of 119, 206, and 300 MeV are presented. The {ital T}=0 data are quite similar to pion absorption data in deuterium. The integrated absorption cross sections scale within errors with the number of isoscaler neutron-proton pairs. The {ital T}=1 cross sections, which correspond to absorption on dineutrons, are an order of magnitude smaller. The angular distributions for isovector absorption show a significant asymmetry, indicating interference effects between amplitudes with or without {Delta} isobars in the intermediate states. The existence of a significant three-nucleon absorption component is established. The integrated absorption cross sections for processes involving two and three nucleons were determined. The neutron and proton momentum probability densities in {sup 3}H were determined from the spectator recoil resulting from quasifree two-nucleon pion absorption.
Published: 1992
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38. First determination of CP violation parameters from K0−0 decay asymmetry

Author: S. Charalambous, D. Francis, T. Alhalel, P. Fassnacht, M. Dodgson, J. Bennet, R. Rickenbach, Claudio Santoni, K. Sarigiannis, João Carvalho, M. Van den Putte, F. Montanet, B. Eckart, C. Thibault, E. Gabathuler, E. Aslanides, A. Filipcic, T. Nakada, Marko Mikuz, Kerstin Jon-And, P Harrison, A. Schopper, F. Touchard, C. Touramanis, R. Ferreira-Marques, H. Cobbaert, H.-J. Gerber, P.-R. Kettle, E. van Beveren, P. Kokkas, J. R. Fry, S. Szilagyi, P.J. Hayman, Ch. Bula, G. Polivka, Ph. Schune, J. Duclos, W.G. Heyes, E. Rozaki, T. Geralis, W. Fetscher, A. Apostolakis, A. Ealet, A. Go, M. Fidecaro, P. Maley, L. Faravel, J.K. Bielein, T. Lawry, G. Varner, T. Ruf, P. Carlson, A. Onofre, J. Pinto Dacunha, P. Pavlopoulos, Christopher Bee, D. Zimmerman, K. Jansson, P. Sanders, S. Vlachos, Christer Fuglesang, C.W.E. Van Eijk, R. Adler, M. Chardalas, Andras Kerek, Marc Dejardin, G. Marel, L. Sacks, L.A. Schaller, F. Triantis, R. Le Gac, Claude Guyot, G. Burgun, A.J.P.L. Policarpo, E. Machado, J. Derre, P. Weber, F. Pelucchi, A. Angelopoulos, R. Kreuger, S. Dedoussis, D.A. Troster, P. Gumplinger, L. Sakeliou, C. Felder, J. Miller, N. Manthos, G. Chardin, Jean-Louis Faure, C. Yeche, D. Garreta, G. Backenstoss, M. Schafer, C. Witzig, R. Gamet, C. Kochowski, H.U. Johner, B. Pagels, L. Tauscher, J.-C. Dousse, H. Postma, D. Zavrtanik, J. Kern, P. Bloch, E. Cawley, R.W. Hollander, and U. Seljak
Subjects: Physics, Systematic error, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, Value (computer science), Asymmetry, Nuclear physics, Pion, CP violation, High Energy Physics::Experiment, Direct proof, Nuclear Experiment, Bar (unit), media_common
Abstract: We report the first determination of CP violation parameters from parameter from particle—antiparticle asymmetry in the decay of neutral kaons into two charged pions. Observation of such an asymmetry is direct proof of CP violation. A fit to the asymmetry enabled a determination of the parameter η+− to be made, yielding the result |η+−|=[2.32±0.14 (stat.)±0.03 (syst.)]×10−3 and σ+−=42.3°±4.4° (stat.)±0.4° (syst.), with an additional uncertainty of ±1.0° due to the error on the present published value of Δm, the KL0-KS0 mass difference. The magnitudes of both statistical and systematic errors will be significantly reduced in the future.
Published: 1992
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39. The CPLEAR particle identification detector

Author: Stef. Charalambous, D. Warner, R. Rickenbach, Jeffrey Boone Miller, P. Pavlopoulos, H.-J. Gerber, R. Ferreira-Marques, F. Pelucchi, S. Szilagyi, F. Montanet, W. Fetcher, Christer Fuglesang, H. Cobbaert, A. Go, David Francis, Panagiotis Kokkas, E. Machado, T. Lawry, G. S. Varner, K. Jansson, E. Rozaki, J. Pinto da Cunha, G. Kesseler, Sp. Dedoussis, João Carvalho, K. Sarigiannis, B.L. Roberts, M. Wildi, A. Apostolakis, A. Onofre, G. Backenstoss, A. Angelopoulos, C. Touramanis, Frixos A Triantis, Patrick Fassnacht, L. Sakeliou, A.J.P.L. Policarpo, J Kuzminski, Kerstin Jon-And, D. Zimmerman, M. Chardalas, P. Carlson, and Andras Kerek
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, Large Hadron Collider, Detector, Particle identification, Momentum, Nuclear physics, Pion, Antiproton, Physics::Accelerator Physics, CP violation, High Energy Physics::Experiment, Detectors and Experimental Techniques, Nuclear Experiment, Instrumentation, Beam (structure)
Abstract: The CPLEAR experiment will measure CP violation parameters in the neutral kaon system, using a low energy antiproton beam from the Low Energy Antiproton Ring (LEAR) at CERN. One of its subdetectors, the Particle Identification Detector (PID), makes a fast separation of pions and kaons, which is essential for the experiment. This article describes the design of the PID and its performance during beam tests and during initial runs at LEAR. A pion rejection efficiency of 99.7% for the first level trigger (after 60 ns) is found in the relevant momentum region.
Published: 1992
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40. LADS — large acceptance detector system for pion-nucleus reactions

Author: N. Simicevic, H. Döbbeling, S. Mukhopadyay, H.J. Weyer, G. van der Steenhoven, M.H. Wang, A. Klein, R. A. Schumacher, D. R. Tieger, D. Rowntree, F.S. Smit, Miroslav Furić, G. S. Kyle, K. E. Wilson, H. Ullrich, Tomislav Petković, H. Breuer, M. Wildi, K. Michaelian, R.P. Redwine, P. A. M. Gram, B. Kotliński, G. Backenstoss, U. Sennhauser, A. Hoffart, and C. H. Q. Ingram
Subjects: Physics, Nuclear and High Energy Physics, Pion, Optics, Physics::Instrumentation and Detectors, business.industry, Large Solid Angle Detector, Detector, Cylinder, High Energy Physics::Experiment, Scintillator, business, Instrumentation
Abstract: A large acceptance detector system (LADS) has been designed and built at the Paul Scherrer Institute to study multi-particle final states after pion-nucleus absorption. It consists of a 28-sector cylinder of plastic scintillator of 1.6 m active length and 1.5 m diameter, and two cylindrical wire chambers; two 14-sector endcaps of plastic scintillator close each end.
Published: 1991
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41. Three-nucleon processes and the total pion absorption cross section in 3He

Author: Miroslav Furić, Damir Bosnar, N. Simicevic, R.J. Powers, Tomislav Petković, M. Steinacher, S. Cierjacks, P. Weber, M. Izycki, B. Rzehorz, P. Salvisberg, A. Hoffart, H. Ullrich, G. Backenstoss, and H.J. Weyer
Subjects: Physics, Nuclear reaction, Nuclear and High Energy Physics, Nuclear Theory, Hadron, Absorption cross section, nuclear reactions, 3He(Pion+, 2p), (Pion-, np) (Pion-, nd), Kinetic energy, Nuclear physics, Pion, Nuclear cross section, Atomic physics, Nuclear Experiment, Nucleon, Absorption (electromagnetic radiation)
Abstract: Pion absorption processes involving three nucleons have been investigated in 3 He with positive and negative pions of 64, 119, 162 and 206 MeV kinetic energy. The most important of these processes is characterized by a constant phase-space density and has comparable integrated cross sections for π + and π − with a Δ-resonance-like dependence on the pion energy. This process constitutes up to one third of the total absorption cross section. The total absorption cross section has been determined by adding up the measured cross sections for all the observed absorption channels.
Published: 1991
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42. Determination of the relative branching ratios for

Author: Philippe Bloch, Andrej Filipcic, Ch. Bula, Stef. Charalambous, D. Warner, J. Derre, A. Go, C. Felder, H.U. Johner, Claude Guyot, L. Sakeliou, T. Geralis, D.A. Troester, G. Backenstoss, H. Postma, E. van Beveren, T. Lawry, C.W.E. van Eijk, J.C. Dousse, David Francis, L. Tauscher, P. Fassnacht, L. Faravel, M. Fidecaro, E. Aslanides, J. Duclos, H.-J. Gerber, R. Kreuger, João Carvalho, G. Marel, C. Touramanis, Christer Fuglesang, W.G. Heyes, E. Kossionides, A. Apostolakis, L. Sacks, T. Paradelis, Frixos A Triantis, R. Le Gac, G. S. Varner, E. Machado, P. Weber, K. Jansson, K. Sarigiannis, L.A. Schaller, A. Onofre, J. R. Fry, J. Bennet, B.L. Roberts, T. Nakada, P. Marotte, Sp. Dedoussis, F. Montanet, A. Schopper, Christopher Bee, P.J. Hayman, P. Pavlopoulos, R. Gamet, Jean-Louis Faure, R. Ferreira-Marques, M. Dodgson, Panagiotis Kokkas, S. Szilagyi, P.F. Harrison, S. Vlachos, D. Garreta, J. Kern, T. Ruf, C. Burgun, M. Van den Putte, W. Fetscher, C. Thibault, E. Gabathuler, R. Rickenbach, Francois Touchard, M. Mikuž, P. Maley, A. Ealet, Danilo Zavrtanik, R.W. Hollander, Ch Yèche, B. Eckart, R. Adler, P. Sanders, M. Chardalas, C. Santoni, A.J.P.L. Policarpo, F. Pelucchi, C. Witzig, C. Kochowski, B. Pagels, Jeffrey Boone Miller, D. Zimmerman, J. Pinto da Cunha, P. Gumplinger, Per Carlson, Marc Dejardin, Andras Kerek, E. Rozaki, P.-R. Kettle, H. Cobbaert, A. Angelopoulos, Kerstin Jon-And, Nikolaos Manthos, Ph. Schune, and U. Seljak
Subjects: Physics, Nuclear and High Energy Physics, Pair production, Annihilation, Pion, Meson, Branching fraction, Antiproton, Protonium, Hadron, Analytical chemistry, Atomic physics
Abstract: The ratio of the branching fractions for p p →K+K− and p p →π+π− was determined with the CPLEAR detector, by stopping antiprotons in a gaseous hydrogen target at 15 bar pressure. It was found to be BR(K+K−)/BR(π+π−)=0.205± 0.016. The fraction of P-wave annihilation at rest at this target density was deduced to be (38±9)%.
Published: 1991
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43. Absorption of negative pions at rest in 3He

Author: M. Dörr, W. Kowald, W. Klotz, N. Fetscher, H.J. Weyer, G. Schmidt, D. Gotta, H. Ullrich, H. Koch, L.M. Simons, G. Backenstoss, U. Raich, P. Blüm, I. Schwanner, and L. Tauscher
Subjects: Rest (physics), Materials science, Pion, Atomic physics, Absorption (electromagnetic radiation)
Published: 2008
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44. Pion absorption in flight on 4He

Author: M. Izycki, A. Hoffart, H. Ullrich, P. Weber, Tomislav Petković, M. Steinacher, P. Salvisberg, G. Backenstoss, Miroslav Furić, H.J. Weyer, B. Rzehorz, and M. Dzemidzić
Subjects: Nuclear reaction, Physics, Nuclear and High Energy Physics, Nuclear Theory, Hadron, Absorption cross section, Baryon, Nuclear physics, Pion, Isospin, pion absorption in flight, nuclear reactions, Atomic physics, Nuclear Experiment, Nucleon, Absorption (electromagnetic radiation)
Abstract: We have measured double and triple coincidences following π + and π − absorption on 4 He at various pion energies. Differential and integrated cross sections are determined for all possible absorption channels. We study and compare the two-nucleon absorption on nucleon pairs with isospin I = 0 and I = 1. In the dNN final-state two absorption mechanisms are identified, one with only one spectator nucleon and one with phase-space behavior. The existence of a three-nucleon absorption component with a spectator nucleon is established and a four nucleon phase-space-like contribution is also identified and found to be small. The total absorption cross section is directly determined by adding the integrated cross sections of all measured reaction channels.
Published: 1990
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45. Physics at CPLEAR

Author: Andrej Filipcic, M. Mikuž, D. Francis, A.J.P.L. Policarpo, P. Bloch, O. Behnke, P. Weber, F. Leimgruber, A. Schopper, M. Schafer, G. Polivka, P.J. Hayman, M. Fidecaro, R. Ferreira-Marques, P.-R. Kettle, P. Bargassa, A. Haselden, O. Wigger, A. Muller, E. Gabathuler, R. Rickenbach, R. Le Gac, P. Pavlopoulos, F. Blanc, Igor Mandić, T. Schietinger, E. Aslanides, Ch Yèche, A. Ealet, Danilo Zavrtanik, C. Thibault, C. Eleftheriadis, A. Go, J. R. Fry, B. Pagels, Marc Dejardin, C. Touramanis, H.-J. Gerber, Michael C. Carroll, T. Ruf, R. Gamet, I. Papadopoulos, L. Sakeliou, Panagiotis Kokkas, Jeffrey Boone Miller, Per Carlson, V. Bertin, R. Kreuger, D. Zimmerman, A. Apostolakis, G. Marel, Nikolaos Manthos, B. L. Roberts, W. Fetscher, A. Benelli, C.W.E. van Eijk, Marcin Wladyslaw Wolter, J. Derre, F. Henry-Couannier, G. Backenstoss, Sotirios Vlachos, A. Angelopoulos, R.W. Hollander, Mats Danielsson, M.B. Chertok, K. Jon-And, Lukas A. Schaller, C.P. Bee, T. Nakada, E. Cawley, F. Touchard, F. Montanet, L. Tauscher, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), CPLEAR, 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 Damoiseaux, Magali
Subjects: Physics, Particle physics, Antiparticle, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], 010308 nuclear & particles physics, General relativity, Time evolution, General Physics and Astronomy, 01 natural sciences, Symmetry (physics), symbols.namesake, Antimatter, 0103 physical sciences, symbols, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], CP violation, EPR paradox, 010306 general physics, Coherence (physics)
Abstract: LEAR offered unique opportunities to study the symmetries which exist between matter and antimatter. At variance with other approaches at this facility, CPLEAR was an experiment devoted to the study of , and symmetries in the neutral-kaon system. A variety of measurements allowed us to determine with high precision the parameters which describe the time evolution of the neutral kaons and their antiparticles, including decay amplitudes, and the related symmetry properties. Limits concerning quantum-mechanical predictions (EPR, coherence of the wave function) or the equivalence principle of general relativity have been obtained. An account of the main features of the experiment and its performances is given here, together with the results achieved. http://www.sciencedirect.com/science/article/B6TVP-47F7DN6-2/1/21e8338e47f0a67bf401b4882a11ceee
Published: 2003

46. STUDIES OF THE CP, T AND CPT SYMMETRIES IN THE NEUTRAL KAON SYSTEM

Author: G. Polivka, W. Fetscher, T. Nakada, C. Thibault, B. L. Roberts, G. Backenstoss, T. Ruf, Francois Touchard, L. Faravel, Marko Mikuz, Sotirios Vlachos, F. Henry-Couannier, F. Blanc, A. Angelopoulos, C. Eleftheriadis, Kerstin Jon-And, Nikolaos Manthos, Danilo Zavrtanik, A. Benelli, C.W.E. van Eijk, R. Le Gac, B. Pagels, M. Fidecaro, V. Bertin, Marcin Wladyslaw Wolter, R. Gamet, J. Derre, Lukas A. Schaller, Andrej Filipcic, A. Muller, M. Schafer, O. Wigger, J. R. Fry, A. Go, A. Apostolakis, E. Gabathuler, R. Kreuger, J. S. Miller, R. Rickenbach, David Francis, Ioannis Papadopoulos, O. Behnke, H.-J. Gerber, Elie Aslanides, Marc Dejardin, F. Leimgruber, A. Schopper, P.J. Hayman, P. Pavlopoulos, D. Zimmerman, Michael C. Carroll, C. Touramanis, P. Weber, P. Carlson, P. Bloch, Panagiotis Kokkas, F. Montanet, Igor Mandić, T. Schietinger, G. Marel, E. Cawley, Mats Danielsson, P.R. Kettle, L. Tauscher, P. Bargassa, A. Haselden, A. Ealet, R.W. Hollander, M.B. Chertok, Lorgeril, Jocelyne, M. Campbell, J.M. Qian, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), CPLEAR, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: Physics, Particle physics, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], Homogeneous space, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex]
Published: 2000
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47. Pion absorptionon4He into theppdfinal state

Author: C. H. Q. Ingram, Mirko Planinic, H.J. Weyer, M. Wildi, K. Michaelian, A. Hoffart, M. Kroedel, Darko Androić, Damir Bosnar, R. P. Redwine, T. Dooling, K. Koch, K. E. Wilson, B. Kotliński, Neven Simicevic, G. Backenstoss, Tomislav Petković, R. Trezeciak, G. S. Kyle, P. A. M. Gram, Avraham Klein, D. Rowntree, J. Köhler, A. Lehmann, Miroslav Furić, N.K. Gregory, H. Ullrich, and A.O. Mateos
Subjects: Physics, Nuclear and High Energy Physics, Pion, Deuterium, Phase space, Yield (chemistry), Solid angle, Semiclassical physics, State (functional analysis), Absorption (logic), Atomic physics
Abstract: Results from a 4{pi} solid angle measurement of the reaction {pi}{sup +}+{sup 4}He{yields}ppd at incident pion energies of T{sub {pi}}{sup +}}=70, 118, 162, 239, and 330 MeV are presented. Integrated cross sections are given for the final states with energetic deuterons (ppd) and (pd)p. The differential cross sections are described by a complete set of five independent variables and various other kinematic variables and compared to cascade and phase space models where deuterons were formed by a semiclassical pickup model. The data are investigated for signatures of initial and final state interactions: it is found that more than half of the (ppd) yield cannot be explained by these mechanisms. The remaining strength is reasonably well reproduced by 3N phase space models followed by pickup. (c) 2000 The American Physical Society.
Published: 2000
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48. Measurement of the energy dependence of the form factor f+ in K0e3 decay

Author: M. Schafer, M. Wolter, E. Gabathuler, R. Rickenbach, P. Weber, E. Cawley, S. Vlachos, R. Le Gac, P. Bloch, I. Mandić, J. R. Fry, T. Schietinger, M.B. Chertok, M. Mikuž, T. Ruf, F. Blanc, Marc Dejardin, D. Zimmerman, P. Carlson, G. Backenstoss, B. Pagels, T. Nakada, P. Kokkas, A. Apostolakis, F. Montanet, Michael C. Carroll, D. Zavrtanik, P. Pavlopoulos, I. Papadopoulos, K. Jon-And, G. Polivka, A. Haselden, L. Tauscher, Jeffrey Boone Miller, N. Manthos, R. Kreuger, M. Fidecaro, A. Ealet, A. Filipčič, R.W. Hollander, G. Marel, L.A. Schaller, O. Wigger, P. Bargassa, C. Thibault, Mats Danielsson, O. Behnke, C. Eleftheriadis, A. Go, F. Leimgruber, A. Schopper, P.J. Hayman, F. Touchard, W. Fetscher, F. Henry-Couannier, A. Muller, A. Benelli, H.-J. Gerber, C.W.E. van Eijk, C. Touramanis, J. Derre, Elie Aslanides, P.-R. Kettle, R. Gamet, D. Francis, B. L. Roberts, V. Bertin, Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), 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), CPLEAR, and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)
Subjects: Physics, Nuclear and High Energy Physics, Particle physics, 010308 nuclear & particles physics, Electroweak interaction, Form factor (quantum field theory), Of the form, 01 natural sciences, Nuclear physics, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], 010306 general physics, Particle Physics - Experiment, Energy (signal processing)
Abstract: Neutral-kaon decays to [pi]e[nu] were analysed to determine the q2 dependence of the K0e3 electroweak form factor f+. Based on 365 612 events, this form factor was found to have a linear dependence on q2 with a slope [lambda]+=0.0245±0.0012stat±0.0022syst. http://www.sciencedirect.com/science/article/B6TVN-414F7YB-Y/1/f9d5dd66c27d4f9264d1cec6fac93c68
Published: 2000

49. First direct observation of time-reversal violation

Author: R. Le Gac, J. R. Fry, H.-J. Gerber, P. Bloch, T. Nakada, F. Montanet, O. Behnke, C. Eleftheriadis, M.B. Chertok, E. Gabathuler, R. Rickenbach, F. Leimgruber, A. Schopper, Kerstin Jon-And, Nikolaos Manthos, P. Pavlopoulos, M. Mikuž, M. Fidecaro, A. Apostolakis, W. Fetscher, P.J. Hayman, R. Gamet, P. Weber, P. Bargassa, C. Touramanis, A. Muller, Ioannis Papadopoulos, T. Ruf, F. Henry-Couannier, P.R. Kettle, L. Tauscher, Marcin Wladyslaw Wolter, Lukas A. Schaller, J. Derre, Panagiotis Kokkas, G. Marel, F. Blanc, A. Go, E. Cawley, Mats Danielsson, O. Wigger, T. Schietinger, David Francis, Sotirios Vlachos, Elie Aslanides, J. S. Miller, A. Angelopoulos, B. Pagels, Marc Dejardin, A. Benelli, C.W.E. van Eijk, A. Haselden, A. Ealet, Igor Mandić, R.W. Hollander, Michael C. Carroll, R. Kreuger, D. Zimmerman, P. Carlson, Danilo Zavrtanik, V. Bertin, M. Schafer, G. Backenstoss, Andrej Filipcic, G. Polivka, C. Thibault, B. L. Roberts, and Francois Touchard
Subjects: Physics, Nuclear physics, Particle physics, Positron, Pion, media_common.quotation_subject, Charge (physics), Electron, Strangeness, Neutrino, Asymmetry, Lepton, media_common
Abstract: Using its unique capability of strangeness tagging at K0 production in pp→K∓π±K0(K0) and at decay with the lepton charge in semileptonic decays CPLEAR measured the semileptonic decay-rate asymmetry R(K0→e+π−ν)−R(K0→e−π+ν)R(K0→e+π−ν)+R(K0→e−π+ν). The asymmetry, fitted over the eigentime interval 1–20 τS, yielded a non-zero result of (6.6±1.3stat±1.1syst)×10−3. A thorough phenomenological anaylsis identifies T violation in K0 mixing and/or CPT violation in semileptonic decays as possible interpretations. A confrontation with world data on neutral kaon decays, however, excludes the latter with sufficient precision to establish the result as the first direct observation of time reversal non-invariance.
Published: 2000
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50. Experimental tests of CPT invaŕiance

Author: C. Thibault, B. L. Roberts, Lukas A. Schaller, M.B. Chertok, R. Le Gac, David Francis, T. Ruf, Francois Touchard, L. Faravel, Michael C. Carroll, J. R. Fry, P. Bargassa, Andrej Filipcic, P. Bloch, F. Blanc, M. Fidecaro, P.R. Kettle, L. Tauscher, C. Touramanis, H.-J. Gerber, A. Go, A. Muller, C. Eleftheriadis, V. Bertin, G. Backenstoss, B. Pagels, G. Marel, Sotirios Vlachos, E. Cawley, A. Angelopoulos, G. Polivka, D. Zimmerman, Patrick Fassnacht, P. Carlson, M. Schafer, E. Gabathuler, T. Nakada, A. Haselden, F. Montanet, M. Mikuž, R. Rickenbach, R. Kreuger, Marcin Wladyslaw Wolter, W. Fetscher, Ioannis Papadopoulos, Panagiotis Kokkas, Kerstin Jon-And, J. Derre, J. S. Miller, Nikolaos Manthos, A. Ealet, Marc Dejardin, T. Schietinger, R.W. Hollander, P. Weber, F. Henry-Couannier, R. Gamet, P. Pavlopoulos, Danilo Zavrtanik, Elie Aslanides, Mats Danielsson, A. Apostolakis, A. Benelli, C.W.E. van Eijk, Igor Mandić, O. Behnke, F. Leimgruber, A. Schopper, and P.J. Hayman
Subjects: Physics, Particle physics, Large Hadron Collider, CPT symmetry, Antimatter, Time evolution, Standard Model
Abstract: The CPLEAR experiment at CERN has directly studied matter and antimatter symmetries via the measurement of the time evolution of K0 and K0. The CPT violation parameter Re(δ) was directly measured with a precision of a few 10−4 while Im(δ) is determined from the Bell-Steinberger relation, with a precision of 10−5. The mass and decay-width equality between the K0 and K0 were tested down to the level of 10−18 GeV.
Published: 2000
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