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1. Study of antiproton annihilation on neutrons into ωπ−π0

Author

M. Suffert, T. Case, H. Kalinowsky, V. Crede, K.M. Crowe, F. Meyer-Wildhagen, R. Landua, C. Regenfus, D. Jamnik, D. Engelhardt, R. Ouared, U. Kurilla, S. Wallis-Plachner, R. P. Haddock, N.P. Hessey, C.A. Baker, C.J. Batty, P. Blüm, K. Peters, Eberhard Klempt, M. A. Faessler, C. A. Meyer, A. V. Sarantsev, M. Benayoun, J. Kisiel, U. Wiedner, Bruce Barnett, D. Walther, U. Thoma, I. Uman, U. Strohbusch, A. V. Anisovich, H. Matthäy, Herbert Koch, Michael Doser, K. Wittmack, J. Reinnarth, K. Braune, P. Kammel, B. Pick, W. Dünnweber, Claude Amsler, F. H. Heinsius, J.S. Suh, Marcel Kunze, Pàl Hidas, and M. Ratajczak

Subjects
Physics, Nuclear physics, Crystal, Nuclear and High Energy Physics, Particle physics, Annihilation, Large Hadron Collider, Deuterium, Antiproton, Partial wave analysis, Neutron, Nuclear Experiment, Spectroscopy
Abstract

Data are presented on antiproton neutron annihilation at rest into ωπ − π 0 taken with the Crystal Barrel detector at LEAR (CERN) using a liquid deuterium target. The partial wave analysis shows evidence for at least two ωπ vector resonances above the ρ (770) ground-state. Possible evidence for a third ρ ′ state with a mass around 1180 MeV is discussed. The results are compared to model dependent predictions concerning the nature of the ρ ′ states.

Published
2004
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2. Annihilation at rest of antiprotons and protons into neutral particles

Author

M. Suffert, C.J. Batty, A. V. Anisovich, V. Crede, U. Thoma, H. Kalinowsky, N.P. Hessey, J.S. Suh, C.A. Baker, C. A. Meyer, M. Heinzelmann, W. Dünnweber, Michael Doser, F. H. Heinsius, D. Jamnik, R. Landua, S. Wallis-Plachner, D. Engelhardt, M. Benayoun, M. A. Faessler, Marcel Kunze, Herbert Koch, Kenneth M. Crowe, K. Wittmack, B. Pick, S. Spanier, K. Peters, D. Walther, B. S. Zou, Claude Amsler, J. Kisiel, U. Strohbusch, U. Wiedner, U. Kurilla, K. Braune, Pàl Hidas, I. Uman, A. V. Sarantsev, P. Kammel, B.M. Barnett, W. Popkov, L. Montanet, R. P. Haddock, P. Blüm, D.V. Bugg, J. Reinnarth, T. Case, H. Matthäy, M. Ratajczak, W. Roethel, Eberhard Klempt, R. Ouared, F. Meyer-Wildhagen, and C. Regenfus

Subjects
Rest (physics), Physics, Nuclear and High Energy Physics, Annihilation, Meson, 010308 nuclear & particles physics, Branching fraction, 01 natural sciences, 7. Clean energy, Nuclear physics, Crystal, Antiproton, 0103 physical sciences, High Energy Physics::Experiment, Atomic physics, Nuclear Experiment, 010306 general physics, Liquid hydrogen, Bar (unit)
Abstract

Annihilation of antiprotons and protons at rest into neutral particles has been studied with the Crystal Barrel detector at LEAR. Annihilation frequencies are determined for final states containing π 0 , η , η ′ and ω mesons using a liquid and a room temperature, 12 bar, gaseous hydrogen target. Including annihilation frequencies for production of neutral kaons from other experiments, the identified reactions for annihilation in liquid hydrogen add up to a branching fraction of (3.56±0.28)% per annihilation compared to the frequency of (3.50±0.30)% with which we observe the all-neutral decay modes inclusively. Since the exclusive final states are normalized to the Crystal Barrel measurement of the π 0 π 0 branching ratio, the latter result is strongly supported by this present study.

Published
2003
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3. Study of at rest

Author

T. Case, H. Matthäy, A. Berdoz, S. Wallis, B. S. Zou, M. Suffert, R. Seibert, P. Kammel, M. Ratajczak, I. Scott, B.M. Barnett, A. Ehmanns, R. Ouared, C. Holtzhaußen, Nigel Hessey, C. Kolo, F. H. Heinsius, R. Landua, B. Pick, Pàl Hidas, H. Stöck, J. Kisiel, C. Völcker, P. Blüm, N. Djaoshvili, Eberhard Klempt, Marcel Kunze, D.V. Bugg, S. Bischoff, K. Wittmack, V. Crede, T. Degener, S. Resag, A. Herbstrith, O. Cramer, M. A. Faessler, M. Herz, U. Kurilla, C.A. Baker, U. Thoma, C. Hodd, J. Adomeit, P. Schmidt, Herbert Koch, C. Regenfus, M. Lakata, W. Dünnweber, A.N. Sarantsev, R. McCrady, M. Benayoun, K. Braune, C. A. Meyer, Kenneth M. Crowe, C. N. Pinder, W. Röthel, H. Kalinowsky, J. Meier, U. Wiedner, M. Tischhäuser, K. Beuchert, D. Jamnik, D. Engelhardt, A. Abele, R. P. Haddock, D. Walther, U. Strohbusch, C. Straßburger, Michael Doser, D. Ryabchikov, L. Montanet, B. Kämmle, C.J. Batty, and K. Peters

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Amplitude, Meson, Hydrogen, chemistry, Branching fraction, Mass spectrum, Resonance, chemistry.chemical_element, Atomic physics, Bar (unit)
Abstract

Crystal Barrel data are presented on p−p → ηπ0π0π0 at rest in liquid hydrogen and also in gaseous hydrogen at 12 bar. Annihilation from the initial 3P0 state relative to 3P2 is stronger in liquid than in gas by a factor 2.46 ± 0.15, in fair agreement with a prediction by Batty. There is a definite peak due to η(1440). Liquid data determine its mass as M = 1413 MeV, Γ = 49 ± 8 MeV. The mass is, however, lower in gas than in liquid by 12 ± 3 MeV; we attribute this mass shift to interference with broad background amplitudes. The η (1440) decays dominantly to ησ: BR [a0(980)π,a0 → ηπ]/BR[ησ] = 0.4 ± 0.2. However, there is strong destructive interference between these two decay modes. There is also a strong, broad ηππ component with JPC = 0−+, consistent with an earlier analysis proposing a very wide η(1800) resonance; it contributes 31% of the ηπ0π0π0 branching ratio in liquid. At the highest ηππ masses, there are definite 2−+ and l++ signals, but we cannot establish precise resonance masses or widths. There is also evidence for the production of f2 (1565), decaying to a2 (1320)π.

Published
1998
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4. Momentum dependence of the decay η→π+π−π0

Author

C. Völcker, K. Beuchert, H. Stöck, A. Ehmanns, M. Heinzelmann, C. Pietra, H. Matthäy, N. Djaoshvili, U. Wiedner, R. Ouared, I. Scott, P. Giarritta, S. Spanier, C. Kolo, U. Kurilla, B. Pick, O. Cramer, F.H. Heinsius, L. Montanet, B. Kämmle, M. Ratajczak, Michael Doser, M. Suffert, A. Herbstrith, D. Walther, S. Wallis, R. Seibert, V. Crede, U. Strohbusch, C. Straßburger, S. Resag, K. Braune, P. Kammel, T. Case, P. Blüm, K.M. Crowe, C. A. Meyer, B.M. Barnett, M. Tischhäuser, M. Herz, K. Peters, R. P. Haddock, K. Wittmack, C. N. Pinder, D.V. Bugg, J. Kisiel, H. Koch, P. Hidas, Claude Amsler, C. J. Batty, N.P. Hessey, C. A. Baker, U. Thoma, C. Hodd, B. S. Zou, M. A. Faessler, T. Degener, P. Schmidt, M. Lakata, W. Dünnweber, H. Kalinowsky, J. Meier, M. Benayoun, R. McCrady, C. Holtzhaußen, C. Regenfus, A. Berdoz, R. Landua, S. Bischoff, J. Adomeit, D. Jamnik, D. Engelhardt, A. Abele, M. Kunze, W. Roethel, F. Ould-Saada, S. v. Dombrowski, and Eberhard Klempt

Subjects
Crystal, Nuclear physics, Momentum, Physics, Nuclear and High Energy Physics, Chiral perturbation theory, Physics::Instrumentation and Detectors, Detector, Barrel (horology), Dalitz plot
Abstract

The π 0 momentum dependence of the decay η → π + π − π 0 has been measured with the Crystal Barrel detector. The analysis is based on 3230 events. The results of this independent measurement are compared to new chiral perturbation theory calculations and previous measurements.

Published
1998
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5. Measurement of the ω → ηγ decay branching ratio

Author

C.A. Baker, A. Ehmanns, J. Kisiel, U. Wiedner, R. P. Haddock, C. Völcker, C. Pietra, Eberhard Klempt, C. N. Pinder, M. Benayoun, S. v. Dombrowski, L. Montanet, F.H. Heinsius, B. Kämmle, K. Beuchert, Marcel Kunze, M. Heinzelmann, Herbert Koch, P. Giarritta, D. Jamnik, P. Blüm, R. Ouared, D. Engelhardt, A. Abele, O. Cramer, I. Scott, V. Crede, U. Strohbusch, C. Straßburger, C. Holtzhaußen, D. Walther, Pàl Hidas, B. Pick, M. Tischhäuser, S. Bischoff, D.V. Bugg, H. Kalinowsky, H. Stöck, R. Landua, Michael Doser, A. Cooper, J. Lüdemann, B. Kalteyer, N.P. Hessey, J. Meier, U. Kurilla, K.M. Crowe, S. Wallis, C.J. Batty, M. A. Faessler, S. Spanier, C. Kolo, R. Hackmann, T. Case, N. Djaoshvili, M. Suffert, R. Seibert, P. Kammel, Claude Amsler, S. Resag, B.M. Barnett, B. S. Zou, K. Peters, M. Lakata, C. Regenfus, C. A. Meyer, K. Braune, U. Thoma, C. Hodd, P. Schmidt, W. Dünnweber, R. McCrady, J. Adomeit, H. Matthäy, A. Berdoz, F. Ould-Saada, T. Degener, M. Ratajczak, W. Roethel, and M. Herz

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Branching fraction, Radiative decay, Mixing (physics)
Abstract

We have measured the branching ratio for the radiative decay ω → ηγ with ω mesons produced in antiproton-proton annihilation at rest into π0ω and ηω. Taking into account ϱ - ω mixing we find a branching ratio B(ω → ηγ) = (6.6 ± 1.7) × 10−4, in accord with the constructive interference solution in other experiments. The upper-limit for the direct radiative decay ω → 3γ is 1.9 × 10−4 at 95% confidence level.

Published
1997
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6. Study of the ππη′ final state in p̄p annihilation at rest

Author

U. Wiedner, V. Crede, M. Suffert, R. Seibert, K.M. Crowe, M. Heinzelmann, I. Scott, M. Herz, J. Kisiel, C. Holtzhauβen, A. Cooper, A. Ehmanns, U. Kurilla, M. Tischhäuser, H. Matthäy, P. Giarritta, L. Montanet, S. Spanier, B. Kämmle, C. Kolo, N.P. Hessey, J. Adomeit, R. Hackmann, W. Roethel, M. A. Faessler, A. Berdoz, S. Resag, C.A. Baker, P. Kammel, N. Djaoshvili, F. Ould-Saada, B.M. Barnett, U. Thoma, C. Hodd, M. Benayoun, F.H. Heinsius, T. Degener, P. Blüm, R. Ouared, B. Pick, K. Beuchert, M. Ratajczak, C. Regenfus, D.V. Bugg, D. Jamnik, H. Kalinowsky, D. Engelhardt, A. Abele, B. Kalteyer, J. Meier, S. Bischoff, K. Braune, C. Straβburger, Pàl Hidas, Claude Amsler, C. Völcker, R. P. Haddock, Marcel Kunze, B. S. Zou, C. Pietra, C. N. Pinder, S. v. Dombrowski, Eberhard Klempt, T. Kiel, H. Stöck, C.J. Batty, O. Cramer, D. Walther, U. Strohbusch, J. Lüdemann, R. Landua, P. Schmidt, W. Dünnweber, R. McCrady, C. A. Meyer, K. Peters, M. Lakata, Herbert Koch, T. Case, and Michael Doser

Subjects
Nuclear physics, Physics, Rest (physics), Nuclear and High Energy Physics, Particle physics, Annihilation, Branching fraction, Partial wave analysis, State (functional analysis)
Abstract

A partial wave analysis of pp → π0π0η′ has been performed using the η′ → π0π0η and η′ → γγ decay modes. The data are dominated by an η′ recoiling against the (ππ) S-wave. In addition, α2 (1320) → η′π0 is needed. There is evidence for contributions from α0(1450) → η′π0. The branching ratio of α0(1450) → η′π0 with respect to ηπ0 is consistent with the prediction of SU(3).

Published
1997
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7. Coupled channel analysis of p annihilation into π0π0π0, π0ηη and π0π0η

Author

R. Ouared, H. Stöck, H. Kalinowsky, Herbert Koch, U. Thoma, Pàl Hidas, P. Giarritta, T. Case, B. Kalteyer, H. Matthäy, B. S. Zou, R. P. Haddock, L. Montanet, B. Kämmle, D. Urner, M. Lakata, N. Djaoshvili, Michael Kobel, K. Braune, S. U. Chung, S. Spanier, C. Kolo, R. Hackmann, P. Blüm, F. H. Heinsius, A. Cooper, C. Felix, J. Brose, D.V. Bugg, C. Holzhaussen, P. Illinger, R. Landua, Claude Amsler, O. Cramer, J. Kisiel, M. Suffert, R. Seibert, E. Schäfer, C.A. Baker, C. Völcker, S. v. Dombroski, C. A. Meyer, P. Schmidt, M. Schütrumpf, Marcel Kunze, W. Dünnweber, M. Herz, F. Walter, F. Ould-Saada, M. Benayoun, R. McCrady, Kenneth M. Crowe, A. Noble, Č. Zupančič, C. Regenfus, P. Birien, T. Degener, D. Walther, J. P. Merlo, U. Strohbusch, C. Straßburger, J. Lüdemann, K. Peters, C.J. Batty, S. Ravndal, U. Wiedner, Michael Doser, M. Tischhäuser, J. Zoll, R. Bossingham, N.P. Hessey, M. A. Faessler, G. Pinter, B. M. Barnett, Eberhard Klempt, T. Kiel, H. P. Dietz, C. N. Pinder, D. S. Armstrong, M. Englert, K. Beuchert, N. Winter, D. Jamnik, and D. Engelhardt

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Annihilation, Dalitz plot, Channel analysis
Abstract

We confirm the existence of the two IG(JPC) = 0+(0++) resonances f0(1370) and f0(1500) reported by us in earlier analyses. The analysis presented here couples the final states π0π0π0, π0π0η and π0ηη of pp annihilation at rest. It is based on a 3 × 3 K-matrix. We find masses and widths of M = (1390±30) MeV, Γ = (380±80) MeV; and M = (1500±10) MeV, Γ = (154 ± 30) MeV, respectively. The product branching ratios for the production and decay into π0π0 and ηη of the f0(1500) are (1.27 ± 0.33) · 10−3 and (0.60 ± 0.17) · 10−3, respectively.

Published
1995
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8. First observation of the production of nucleon resonances in antiproton annihilation in liquid deuterium

Author

N. Djaoshvili, U. Thoma, Eberhard Klempt, T. Kiel, H. P. Dietz, D. Urner, J. Kisiel, C.J. Batty, P. Giarritta, F. H. Heinsius, C. N. Pinder, S. v. Dombrowski, D. S. Armstrong, N.P. Hessey, U. Wiedner, H. Matthaey, J. Lüdemann, P. Schmidt, M. Suffert, R. Seibert, M. Lakata, F. Ould-Saada, M. Merkel, Michael Doser, J. Zoll, W. Dünnweber, C. Holzhaussen, B. S. Zou, R. McCrady, U. Strohbusch, D. Walther, C. Straßburger, M. A. Faessler, C. Felix, T. Degener, H. Koch, R. Landua, Mark J. Burchell, K. Braune, I. Augustin, C. Völcker, P. Illinger, T. Gemesy, P. Birien, A. Cooper, L. Montanet, J. Brose, B. Kämmle, Pàl Hidas, Krisztian Peters, Marcel Kunze, R. Ouared, M. Tischhäuser, C. A. Meyer, B.M. Barnett, M. Herz, R. Bossingham, A. Noble, C. Regenfus, T. Case, Claude Amsler, Č. Zupančič, Michael Kobel, J. P. Merlo, K. Königsmann, P. Blüm, D.V. Bugg, H. Stöck, B. Kalteyer, H. Kalinowsky, S. Spanier, C. Kolo, R. Hackmann, O. Cramer, E. Schäfer, S. Resag, C.A. Baker, F. Walter, M. Benayoun, Kenneth M. Crowe, S. Ravndal, R. P. Haddock, K. Beuchert, N. Winter, D. Jamnik, D. Engelhardt, and M. Englert

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Deuterium, Antiproton, Nucleon, Particle Physics - Experiment
Published
1995
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9. High-statistics study of f0(1500) decay into π0π0

Author

C. Völcker, H. Kalinowsky, L. Montanet, B. Kämmle, Marcel Kunze, C. Kolo, Nigel Hessey, J. Kisiel, O. Cramer, C.A. Baker, R. Hackmann, C. A. Meyer, P. Blüm, Claude Amsler, M. Lakata, F. Walter, E. Schäfer, M. Suffert, R. Seibert, U. Wiedner, F. H. Heinsius, T. Case, H. Matthäy, Kenneth M. Crowe, R. Landua, Michael Doser, K. Beuchert, F. Ould-Saada, J. P. Merlo, P. Schmidt, J. Zoll, S. Spanier, K. Königsmann, A. Noble, H. Stöck, M. A. Faessler, W. Dünnweber, Herbert Koch, N. Winter, G. Pinter, T. Degener, M. Herz, B.M. Barnett, U. Thoma, K. Braune, S. U. Chung, D. Jamnik, R. Bossingham, Č. Zupančič, F. Loser, Mark J. Burchell, D. Engelhardt, D. Urner, C. Regenfus, C. Felix, K. Peters, Michael Kobel, P. Birien, Pàl Hidas, R. P. Haddock, M. Englert, C. N. Pinder, S. v. Dombrowski, D. S. Armstrong, M. Merkel, D. Walther, U. Strohbusch, C. Straßburger, J. Lüdemann, J. Brose, C.J. Batty, I. Augustin, S. Ravndal, Eberhard Klempt, T. Kiel, H. P. Dietz, J. Salk, and P. Illinger

Subjects
Data set, Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Angular distribution, Partial wave analysis, Scalar (mathematics), Dalitz plot, Resonance (particle physics)
Abstract

A partial-wave analysis of the reaction p p →π 0 π 0 π 0 has been performed using a high-quality high-statistics data set of 712 000 events. In addition to the f0(975) and f0(1300), the scalar resonance with mass m = (1500 ± 15) MeV and width Γ = (120 ± 25) MeV is necessary to describe the data.

Published
1995
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10. ηη′ threshold enhancement in p̄p annihilations into π0ηη′ at rest

Author

R. Bossingham, M. Suffert, R. Seibert, C. N. Pinder, S. v. Dombrowski, D. S. Armstrong, F. Loser, Claude Amsler, U. Wiedner, M. Merkel, C.A. Baker, Michael Doser, F. H. Heinsius, I. Augustin, P. Schmidt, W. Dünnweber, J. P. Merlo, K. Peters, K. Königsmann, R. Hackmann, A. Cooper, C.J. Batty, F. Walter, Herbert Koch, Michael Kobel, P. Blüm, D.V. Bugg, M. Lakata, H. Kalinowsky, R. P. Haddock, Kenneth M. Crowe, B. M. Barnett, B. S. Zou, O. Cramer, M. A. Faessler, E. Schäfer, Eberhard Klempt, S. Ravndal, Mark J. Burchell, M. Englert, T. Kiel, H. P. Dietz, D. Walther, R. Landua, C. A. Meyer, C. Kolo, U. Strohbusch, Pàl Hidas, L. Montanet, B. Kämmle, Nigel Hessey, K. Beuchert, A. Noble, J. Lüdemann, N. Winter, P. Illinger, D. Jamnik, D. Engelhardt, J. Salk, J. Brose, K. Braune, S. U. Chung, T. Case, H. Matthäy, P. Birien, S. Spanier, C. Straβburger, G. Pinter, C. Völcker, Marcel Kunze, Č. Zupančič, D. Urner, C. Felix, J. Kisiel, F. Ould-Saada, T. Degener, M. Herz, and J. Zoll

Subjects
Physics, Rest (physics), Nuclear and High Energy Physics, Particle physics, Dalitz plot
Abstract

We report on the observation of an ηη′ threshold enhancement produced in pp annihilations at rest into π0ηη′, which we identify with the recently discovered ƒ 0 (1500) .

Published
1994
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11. Hidden and open $$\bar ss$$ production in $$\bar pp$$ annihilation at restannihilation at rest

Author

A. H. Sanjari, D. Walther, K. Beuchert, R. Hackmann, J. Zoll, N. Winter, U. Strohbusch, P. Blüm, D. Jamnik, D. Engelhardt, C.A. Baker, F. Walter, Kenneth M. Crowe, Pàl Hidas, C. Kolo, J. Lüdemann, C. A. Meyer, D.V. Bugg, P. Birien, I. Augustin, S. Spanier, K. Peters, B. Schmid, G. Pinter, T. Case, B. Kämmle, James A. Bistirlich, T. Kiel, J. Salk, J. P. Merlo, K. Braune, B. M. Barnett, R. P. Haddock, C.J. Batty, L. Montanet, R. Bossingham, K. Königsmann, M. Englert, A. Noble, M. Suffert, F. H. Heinsius, U. Wiedner, R. Landua, C. Völcker, P. Schmidt, A. Cooper, Michael Doser, S. Ravndal, Mark J. Burchell, Marcel Kunze, W. Dünnweber, Claude Amsler, M. A. Faessler, Herbert Koch, H. Matthaey, Nigel Hessey, J. Brose, S. v. Dombrowski, D. S. Armstrong, M. Merkel, Eberhard Klempt, H. P. Dietz, Z. Jávorfi, F. Ould-Saada, C. Straßburger, G. Folger, C. Felix, Michael Kobel, D. Urner, J. Kisiel, H. Bossy, H. Kalinowsky, O. Cramer, E. Schäfer, Č. Zupančič, and P. Illinger

Subjects
Nuclear physics, Physics, Particle physics, Annihilation, OZI rule, High Energy Physics::Phenomenology, Dalitz plot, High Energy Physics::Experiment
Abstract

New branching ratios for\(\bar pp\) annihilation at rest into final states with a\(K\bar K\) pair or φ-meson are being measured with the Crystal Barrel detector at LEAR. The yield of φγ, relative to ωγ, appears to violate the OZI rule as strongly as φπ relative to ωπ.

Published
1994
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12. High-statistics analysis of $$\bar pp \to \pi ^0 \pi ^0 \pi ^0 $$ at restat rest

Author

L. Montanet, U. Meyer-Berkhout, Mark J. Burchell, C.J. Batty, B. Schmid, G. Pinter, T. Case, R. Bossingham, A. H. Sanjari, K. Braune, J. Zoll, C. Kolo, M. Suffert, S. Ravndal, K. Beuchert, Claude Amsler, C.A. Baker, R. Hackmann, F. Walter, D. Walther, N. Winter, P. Birien, I. Augustin, Kenneth M. Crowe, M. A. Faessler, D. Jamnik, U. Strohbusch, F. H. Heinsius, C. Völcker, K. Peters, D. Engelhardt, Pàl Hidas, H. Matthaey, H. Kalinowsky, C. A. Meyer, James A. Bistirlich, P. Schmidt, O. Cramer, J. Lüdemann, R. P. Haddock, W. Dünnweber, A. Noble, E. Schäfer, J. Salk, Marcel Kunze, U. Wiedner, R. Landua, Herbert Koch, Michael Doser, S. Spanier, B. Kämmle, P. Illinger, A. Cooper, M. Englert, B. M. Barnett, Nigel Hessey, J. P. Merlo, K. Königsmann, P. Blüm, D.V. Bugg, T. Kiel, G. Folger, Michael Kobel, Č. Zupančič, J. Kisiel, C. Felix, H. Bossy, Z. Jávorfi, C. Straßburger, J. Brose, Eberhard Klempt, H. P. Dietz, D. Urner, S. v. Dombrowski, and M. Merkel

Subjects
Nuclear physics, Rest (physics), Physics, Particle physics, Annihilation, Amplitude, Pi, Dalitz plot, Invariant (mathematics), Nuclear Experiment, Resonance (particle physics), Bar (unit)
Abstract

Antiproton-proton annihilation at rest into 3π0 is analysed based on a data sample of about 500 000 high-quality 3π0 events. In this high-statistics Dalitz plot two structures in the region of π0π0 invariant masses of about 1500 MeV show up, a small band and a blob at higher masses. In a first attempt to describe the data two different models are used to parametrize the dynamical amplitudes leading to the same conclusion: the data require a 0+ + and also a 2+ + resonance in the 1500 MeV region.

Published
1994
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13. Test of chiral perturbation theory in η decays

Author

R. Bossingham, C. A. Meyer, J. Lüdemann, R. P. Haddock, A. Noble, A. Cooper, M. A. Faessler, A. H. Sanjari, T. Case, B. Schmid, H. Matthäy, G. Pinter, K. Braune, J. Zoll, C. Felix, B. M. Barnett, P. Schmidt, D. Walther, Eberhard Klempt, G. Folger, L. Montanet, W. Dünnweber, James A. Bistirlich, H. P. Dietz, Michael Kobel, Pàl Hidas, C.A. Baker, D. Umer, Claude Amsler, M. Suffert, I. Augustin, F. Walter, R. Hackmann, S. v. Dombrowski, D. S. Armstrong, P. Birien, Kenneth M. Crowe, M. Merkel, H. Kalinowski, Č. Zupančič, Z. Jávorfi, B. Kämmle, K. Beuchert, C. Kolo, F. Ould-Saada, C. Straßburger, D. Jamnik, P. Illinger, N. P. Hessey, D. Engelhardt, J. Brose, F. H. Heinsius, C. Völcker, U. Wiedner, Michael Doser, Mark J. Burchell, J. P. Merlo, M. Englert, Marcel Kunze, K. Königsmann, T. Kiel, J. Kisiel, H. Bossy, S. Ravndal, P. Blüm, D.V. Bugg, J. Salk, S. Waßmer, C.J. Batty, H. Koch, U. Strohbusch, R. Landua, E. Schäfer, and Krisztian Peters

Subjects
Quantum chromodynamics, Crystal, Nuclear physics, Physics, Particle physics, Chiral perturbation theory, Pion, Partial width, Order (group theory), Charged particle
Abstract

The decay of the η-meson into three pions plays an important role as a test of low-energy QCD calculations in the framework of chiral perturbation theory. Previous experiments show results that are inconclusive or even contradictory. The Crystal Barrel experiment at LEAR has determined the braching ratiosΓ(η→3π0)/Γ(η→π+π−π0)=1.47±0.09±0.15 andΓ(η→γγ)/Γ(η→π+π−π0)=1.88±0.10±0.17 using its unique features to detect charged particles as well as neutral particles. The value for the first ratio agrees nicely with the theoretical predictions and solves previous experimental uncertainties. The second value, which yields a partial width ofΓ(η→π+π−π0)=(0.24±0.03) keV, shows that the same next-to-leading order chiral perturbation theory calculations still have some problems.

Published
1994
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14. Antiproton annihilation at rest in liquid deuterium into π−π0π0pS

Author

Pàl Hidas, M. Suffert, C. Kolo, Nigel Hessey, J. Brose, T. Kiel, B. Schmid, M. A. Faessler, R. Bossingham, G. Pinter, U. Meyer-Berkhout, R. Hackmann, U. Wiedner, H. Matthaey, Eberhard Klempt, Michael Doser, R. Landua, C.J. Batty, P. Schmidt, P. Illinger, A. H. Sanjari, J. Zoll, H. P. Dietz, C.A. Baker, L. Montanet, J. P. Merlo, S. v. Dombrowski, F. Walter, K. Königsmann, W. Dünnweber, S. Ravndal, J. Kisiel, C. A. Meyer, D. Walther, Kenneth M. Crowe, M. Merkel, I. Augustin, A. Cooper, H. Bossy, U. Strohbusch, K. Peters, B. Kämmle, Mark J. Burchell, R. P. Haddock, K. Braune, S. Spanier, A. Noble, J. Lüdemann, H. Kalinowsky, Herbert Koch, P. Birien, D. Urner, F. H. Heinsius, C. Völcker, E. Schäfer, Z. Jávorfi, C. Straßburger, Marcel Kunze, Claude Amsler, James A. Bistirlich, T. Case, G. Folger, Michael Kobel, P. Blüm, C. Felix, D.V. Bugg, Č. Zupančič, M. Englert, B. M. Barnett, K. Beuchert, N. Winter, D. Jamnik, and D. Engelhardt

Subjects
Nuclear physics, Physics, Crystal, Annihilation, Deuterium, Antiproton, Partial wave analysis, Resonance, Dalitz plot, Atomic physics, Parametrization
Abstract

With the Crystal Barrel detector, the final state π−π0π0pS at rest in liquid deuterium was measured for the first time. A preliminary partial-wave analysis was performed, which required two interesting features: besides the ρ(770), a second pole was needed in the ππP-wave and a narrow resonance in the ππS-wave, slightly above 1500 MeV/c2. With the same parametrization a high-statistics π+π−π0 data set could also be well described.

Published
1994
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15. Observation of a new IG(JPC)=1−(0++) resonance at 1450 MeV

Author

P. Schmidt, W. Dünnweber, C. Felix, U. Wiedner, Michael Doser, B. S. Zou, Eberhard Klempt, D. Urner, C. Kolo, L. Montanet, B. Kämmle, F. Loser, I. Augustin, T. Kiel, H. P. Dietz, C.J. Batty, Pàl Hidas, K. Peters, J. P. Merlo, R. Hackmann, J. Kisiel, C.A. Baker, A. V. Sarantsev, F. H. Heinsius, S. Ravndal, Herbert Koch, V. V. Anisovich, M. Suffert, D. Walther, J. Zoll, F. Walter, U. Strohbusch, G. Pinter, K. Königsman, Mark J. Burchell, Kenneth M. Crowe, Michael Kobel, J. Lüdemann, A. Cooper, J. Brose, S. von Dombrowski, B. M. Barnett, F. Ould-Saada, C. A. Meyer, Č. Zupančič, S. Spanier, P. Blüm, H. Kalinowsky, C. N. Pinder, A. Noble, R. Landua, D. S. Armstrong, T. Degener, M. Herz, D.V. Bugg, M. Merkel, P. Illinger, E. Schäfer, J. Salk, Nigel Hessey, C. Völcker, Marcel Kunze, C. Straβburger, R. Bossingham, Claude Amsler, K. Braune, S. U. Chung, M. A. Faessler, T. Case, H. Matthäy, M. Englert, P. Birien, R. P. Haddock, K. Beuchert, N. Winter, D. Jamnik, and D. Engelhardt

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Annihilation, Partial wave analysis, Resonance, Dalitz plot, Elementary particle, Quantum number
Abstract

A new IG=1− JPC=0++πη resonance is observed in pp annihilation at rest into π0π0η. It has a mass M=(1450±40)MeV and a width Γ=(270±40)MeV.

Published
1994
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16. Observation of two JPC=0++ isoscalar resonances at 1365 and 1520 MeV

Author

Nigel Hessey, P. Blüm, C.A. Baker, A. V. Sarantsev, G. Folger, D.V. Bugg, R. Landua, K.M. Crowe, Michael Kobel, B. S. Zou, Eberhard Klempt, H. P. Dietz, G. Pinter, Pàl Hidas, P. Schmidt, F. Walter, J. Lüdemann, H. Koch, W. Dünnweber, J. P. Merlo, K. Königsmann, Krisztian Peters, B. M. Barnett, P. Illinger, M. Suffert, H. Kalinowsky, H. Matthäy, R. Bossingham, U. Wiedner, S. Spanier, U. Strohbusch, A. Noble, A. Cooper, J. Brose, J. Kisiel, Mark J. Burchell, E. Schäfer, Michael Doser, V. V. Anisovich, C. Kolo, L. Montanet, B. Kämmle, C. N. Pinder, T. Kiel, I. Augustin, K. Braune, D. Walther, D. S. Armstrong, Z. Jávorfi, C.J. Batty, C. Felix, C. Straßburger, M. Merkel, B. Schmid, M. A. Faessler, S. Ravndal, T. Degener, J. Salk, F. H. Heinsius, C. Völcker, A. H. Sanjari, J. Zoll, Marcel Kunze, T. Case, R. Hackmann, P. Birien, K. Beuchert, C. A. Meyer, N. Winter, D. Jamnik, D. Engelhardt, M. Englert, and R. P. Haddock

Subjects
Nuclear physics, Elastic scattering, Physics, Nuclear and High Energy Physics, Amplitude, Isoscalar, Resonance, Dalitz plot, Particle Data Group
Abstract

From a simultaneous analysis of data on pp → π0π0π0 and pp → ηηπ0 at rest, two I = 0, JPC = 0++ resonances are identified above 1 GeV. The first has mass M = 1365−55+20 MeV and width г = 268 ± 70 MeV, close to the ƒ0(1400) of the Particle Data Group. The second has M = 1520 ± 25 MeV, г = 148−25+20 MeV.

Published
1994
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17. Antiproton-proton annihilation at rest into two mesons

Author

C. A. Meyer, A. Noble, U. Meyer-Berkhout, B. Schmid, R. P. Haddock, T. Case, P. Schmidt, A. H. Sanjari, G. Pinter, D. Walther, K. Beuchert, J. Zoll, N. Winter, D. Jamnik, D. Engelhardt, W. Dünnweber, Claude Amsler, J. Brose, B. M. Barnett, M. Englert, C.A. Baker, U. Strohbusch, D. Urner, R. Hackmann, M. Suffert, J. Lüdemann, A. Cooper, F. Walter, Herbert Koch, P. Blüm, H. Kalinowsky, K. Peters, C.J. Batty, J. Kisiel, Mark J. Burchell, R. Landua, M. A. Faessler, D.V. Bugg, H. Bossy, E. Schäfer, James A. Bistirlich, Pàl Hidas, U. Wiedner, Kenneth M. Crowe, Michael Doser, S. v. Dombrowski, G. Folger, I. Augustin, Michael Kobel, K. Braune, S. U. Chung, M. Merkel, S. Ravndal, J. P. Merlo, L. Montanet, S. Spanier, B. Kämmle, K. Königsmann, Nigel Hessey, P. Illinger, C. Kolo, P. Birien, F. H. Heinsius, Eberhard Klempt, C. Völcker, H. P. Dietz, Marcel Kunze, T. Kiel, H. Matthaey, R. Bossingham, Z. Jávorfi, C. Straßburger, Č. Zupančič, and C. Felix

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Meson, Antiproton, Radiative transfer, High Energy Physics::Experiment, Nuclear Experiment, Liquid hydrogen
Abstract

Branching ratios for antiproton-proton annihilations at rest into two mesons are given. The data were obtained at LEAR by stopping antiprotons in a liquid hydrogen target. Both charged and neutral annihilation products were detected in the Crystal Barrel detector. Representative data are presented, and their bearing on the general picture of annihilation dynamics is discussed. In addition, preliminary branching ratios for two-body radiative annihilations are given.

Published
1993
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18. P- versus S-wave at rest in LH2

Author

C. Felix, A. Cooper, F. H. Heinsius, Herbert Koch, M. Suffert, C. Völcker, A. H. Sanjari, Marcel Kunze, D. Urner, Pàl Hidas, Č. Zupančič, G. Folger, Michael Kobel, H. Kalinowsky, C. A. Meyer, Bernhard Schmid, D. Walther, J. Zoll, Eberhard Klempt, Nigel Hessey, James A. Bistirlich, J. Brose, H. P. Dietz, J. Kisiel, S. Spanier, A. Noble, R. Landua, T. Kiel, U. Meyer-Berkhout, E. Schäfer, H. Bossy, G. Pinter, M. Englert, C. Straβburger, L. Montanet, B. Kämmle, U. Strohbusch, H. Matthaey, S. von Dombrowski, P. Schmidt, W. Dünnweber, M. Merkel, P. Illinger, K. Braune, J. Lüdemann, C.J. Batty, Mark J. Burchell, S. Ravndal, Claude Amsler, J. P. Merlo, K. Königsmann, K. Beuchert, N. Winter, R. Hackmann, D. Jamnik, P. Blüm, D. Engelhardt, D.V. Bugg, I. Augustin, K. Peters, R. P. Haddock, U. Wiedner, Michael Doser, C.A. Baker, M. A. Faessler, F. Walter, R. Bossingham, Kenneth M. Crowe, P. Birien, T. Case, B. M. Barnett, and C. Kolo

Subjects
Physics, Nuclear and High Energy Physics, Angular momentum, Annihilation, Antiproton, Branching fraction, S-wave, Atom, Atomic physics
Abstract

The annihilation p p →π 0 π 0 was measured for antiprotons stopped in liquid hydrogen (LH2). This reaction is only allowed from odd angular momentum states of the p p - atom . The resulting branching ratio BR ( p p →π 0 π 0 ) LH 2 =(6.93±0.22 stat ±0.37 syst )×10 −4 , combined with a previous measurement of the branching ratio BR ( p p →π + π − ) 2 P in gas from the 2P-state of p p suggests a fraction of P-wave annihilation in LH2 of (28.8±3.5)%, much larger than the values obtained from other annihilation channels. A method of reconciling the contradictory results is discussed.

Published
1992
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19. Proton-antiproton annihilation into ηηπ-observation of a scalar resonance decaying into ηη

Author

Herbert Koch, C. Felix, U. Meyer-Berkhout, Z. Jávorfi, G. Pinter, C. A. Meyer, A. Noble, R. Hackmann, T. Kiel, S. Spanier, L. Montanet, B. Kämmle, C.A. Baker, S. von Dombrowski, B. M. Barnett, R. P. Haddock, Č. Zupančič, U. Wiedner, Kenneth M. Crowe, K. Beuchert, R. Landua, Michael Doser, H. Matthaey, N. Winter, F. H. Heinsius, P. Schmidt, C. Völcker, C. Kolo, D. Jamnik, D. Engelhardt, H. Bossy, C. J. Batty, Marcel Kunze, W. Dünnweber, A. H. Sanjari, S. Ravndal, M. Englert, Eberhard Klempt, H. P. Dietz, J. P. Merlo, I. Augustin, K. Königsmann, R. Bossingham, P. Blüm, D. Walther, B. Schmid, U. Strohbusch, D.V. Bugg, A. Cooper, P. Illinger, J. Lüdemann, D. Urner, T. Case, C. Straβburger, James A. Bistirlich, K. Braune, J. Zoll, M. Merkel, Nigel Hessey, Mark J. Burchell, Pàl Hidas, C. Amsler, P. Birien, M. A. Faessler, M. Suffert, K. Peters, G. Folger, H. Kalinowsky, R. Beckmann, and E. Schäfer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Proton, 010308 nuclear & particles physics, Isoscalar, Nuclear Theory, Scalar (mathematics), Dalitz plot, 01 natural sciences, Resonance (particle physics), Nuclear physics, Antiproton, 0103 physical sciences, Mass spectrum, 010306 general physics
Abstract

The results of a measurement of pp annihilation at rest into ηηπ 0 are presented. Assuming a resonance dominated model for the annihilation process an isoscalar J PC =0 ++ resonance decaying into ηη is observed with a mass of 1560±25 MeV/ c 2 and a width of 245±50 MeV/ c 2 .

Published
1992
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20. Observation of f0(1500) decay into K(L) K(L)

Author

M. Suffert, R. Seibert, P. Schmidt, J. Brose, S. Bischoff, W. Dünnweber, G. Pinter, P. Giarritta, B. M. Barnett, U. Thoma, R. McCrady, Eberhard Klempt, D. Urner, T. Kiel, H. P. Dietz, U. Wiedner, Claude Amsler, C.A. Baker, J. Kisiel, I. Scott, F. H. Heinsius, N.P. Hessey, C.J. Batty, F. Ould-Saada, C. N. Pinder, W. Roethel, C. Regenfus, M. A. Faessler, S. v. Dombrowski, D. S. Armstrong, T. Degener, M. Lakata, F. Walter, C. Völcker, K. Braune, A. Cooper, J. Adomeit, T. Case, H. Matthäy, M. Benayoun, Marcel Kunze, C. Holtzhaußen, P. Blüm, M. Tischhäuser, Kenneth M. Crowe, R. Ouared, D.V. Bugg, L. Montanet, B. Kämmle, S. Spanier, C. Kolo, N. Djaoshvili, R. Hackmann, R. Landua, A. Berdoz, P. Kammel, S. Resag, Č. Zupančič, H. Kalinowsky, B. Kalteyer, J. Meier, D. Walther, R. P. Haddock, M. Herz, U. Strohbusch, C. Straßburger, K. Beuchert, D. Jamnik, D. Engelhardt, A. Abele, J. Lüdemann, J. Reißmann, H. Stöck, C. A. Meyer, Pàl Hidas, A. Noble, O. Cramer, Michael Doser, E. Schäfer, K. Peters, B. S. Zou, and Herbert Koch

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Amplitude, Annihilation, OZI rule, Particle Physics - Experiment, Production rate
Abstract

The f 0 (1500) is observed in its K K decay mode in an amplitude analysis of high statistics data in p p annihilation at rest into π 0 K L K L . The mass and width is found to be ( m , Γ ) = (1515 ± 20, 105 ± 15) MeV. A comparison of the decay rate into 2 π 0 shows that this state cannot be dominantly s s . The f ′ 2 (1525) has been observed for the first time in p p annihilation and its production rate is consistent with the expectation from the OZI rule.

Published
1996

21. Antiproton-proton annihilation in-flight

Author

M. Englert, C.A. Baker, P. Schmidt, W. Dünnweber, D. Urner, I. Augustin, K. Peters, B. Schmid, G. Pinter, S. von Dombrowski, Herbert Koch, U. Wiedner, R. Bossingham, M. Suffert, Michael Doser, Č. Zupančič, J. Salk, C. Felix, D. S. Armstrong, C.J. Batty, P. Blüm, Z. Jávorfi, F. Ould-Saada, C. Straßburger, A. Cooper, D.V. Bugg, B. M. Barnett, Mark J. Burchell, A. H. Sanjari, T. Case, J. Zoll, R. Hackmann, T. Kiel, P. Birien, R. Landua, Pàl Hidas, K. Braune, J. Kisiel, S. Ravndal, Nigel Hessey, C. A. Meyer, J. P. Merlo, K. Königsmann, R. P. Haddock, S. Spanier, A. Noble, U. Meyer-Berkhout, G. Folger, L. Montanet, D. Walther, B. Kämmle, Michael Kobel, U. Strohbusch, K. Beuchert, N. Winter, H. Matthaey, J. Lüdemann, D. Jamnik, D. Engelhardt, F. H. Heinsius, C. Völcker, J. Bistirlich, Marcel Kunze, C. Kolo, J. Brose, Claude Amsler, H. Bossy, M. A. Faessler, H. Kalinowsky, K. M. Crowe, P. Illinger, E. Schäfer, M. Merkel, Eberhard Klempt, H. P. Dietz, Heyd, Yvette, Institut de Recherches Subatomiques (IReS), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Particle physics, Annihilation, Proton, 010308 nuclear & particles physics, [PHYS.NEXP] Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear Theory, Dalitz plot, Observable, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Pseudoscalar, Nuclear physics, Antiproton, 0103 physical sciences, Invariant mass, Nuclear Experiment, 010306 general physics, Bar (unit)
Abstract

This is an overview of the preliminary results of\(\bar pp\) annihilation at incident\(\bar p\) momenta of 600, 1200 and 1940 MeV/c(*). The data was taken at LEAR with the Crystal Barrel Detector (E. Akeret al.:Nucl. Instrum. Methods A,321, 108 (1992)). In the two pseudoscalar final states seven different channels are observable and their angular distributions are measured. They are compared to older data, if existent, and are found to be equal within the experimental errors. In the three-meson final states, an overview of the already examined final states is given. Striking signals in the Dalitz plots and invariant-mass projections for a set of final states are observed. In the final states ηηπ0 and ηηη a signal ηη with the invariant mass of 1480 MeV/c2 and a width of aboutΓ≈≈70 MeV/c2 is visible. In the final-state ωηπ0 a signal in the ωη invariant-mass spectrum at 1680 MeV/c2 with a widthΓ≈150 MeV/c2 is observed. Finally, in the final-state ωωπ0 two visible structures in the Dalitz plot are detected at 1600 MeV/c2 (Γ≈90 MeV/c2) and 1900 MeV/c2 (Γ≈150 MeV/c2).

Published
1994

22. New results from crystal barrel

Author

Herbert Koch, L. Montanet, A. H. Sanjari, B. Kämmle, T. Case, J. Zoll, A. Cooper, P. Blüm, M. Suffert, C.A. Baker, D.V. Bugg, F. Walter, S. Spanier, J. P. Merlo, K. Königsmann, Pàl Hidas, C. A. Meyer, K. Beuchert, R. P. Haddock, C.J. Batty, A. Noble, N. Winter, D. Jamnik, D. Urner, D. Engelhardt, C. Kolo, D. S. Armstrong, Nigel Hessey, S. Ravndal, B. Schmid, G. Pinter, R. Hackmann, D. Walther, U. Wiedner, Claude Amsler, Michael Doser, H. Bossy, Mark J. Burchell, U. Strohbusch, J. Kisiel, J. Lüdemann, S. Waßmer, Č. Zupančič, T. Kiel, K. Braune, J. Salk, M. Englert, I. Augustin, F. H. Heinsius, C. Völcker, J. Bistirlich, K. Peters, C. Felix, S. v. Dombrowski, Marcel Kunze, Z. Jávorfi, F. Ould-Saada, C. Straßburger, P. Schmidt, W. Dünnweber, B. M. Barnett, P. Birien, R. Landua, R. Bossingham, H. Matthaey, S. U. Chung, K. M. Crowe, P. Illinger, M. Merkel, H. Kalinowsky, E. Schäfer, J. Brose, M. A. Faessler, Eberhard Klempt, H. P. Dietz, G. Folger, Michael Kobel, Heyd, Yvette, Institut de Recherches Subatomiques (IReS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), and CRYSTAL BARREL

Subjects
Physics, Particle physics, Meson, [PHYS.HEXP] Physics [physics]/High Energy Physics - Experiment [hep-ex], 010308 nuclear & particles physics, High Energy Physics::Lattice, Nuclear Theory, High Energy Physics::Phenomenology, Barrel (horology), Dalitz plot, 01 natural sciences, 3. Good health, Crystal, Nuclear physics, Hadron spectroscopy, 0103 physical sciences, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], High Energy Physics::Experiment, Nuclear Experiment, 010306 general physics, Spectroscopy, Bar (unit)
Abstract

Results are presented on meson spectroscopy, two-body final states and meson decay modes observed in\(\bar pp\) annhilation at rest by the Crystal Barrel experiment at LEAR.

Published
1994

23. The Crystal Barrel spectrometer at LEAR

Author

J. Zoll, C. A. Meyer, K. Sidiropoulos, H. Kalinowsky, M. Merkel, Claude Amsler, A. Noble, E. Schäfer, Kenneth M. Crowe, J.M. Friedrich, T. Kiel, C. Felix, D. Urner, C. J. Batty, H. Hammer, A. Staude, S. Spanier, S. M. Walther, U. Meyer-Berkhout, R. Bossingham, Eberhard Klempt, W. Rohrbach, B. Schmid, I. Augustin, L. Montanet, B. M. Barnett, D. Walther, J. P. Merlo, M. Suffert, H. Koch, Č. Zupančič, Mark J. Burchell, K. Königsmann, B. Kämmle, R. P. Haddock, G. Folger, P. Birien, C. Kolo, H. Matthaey, K. Peters, F. Krennrich, H. Emerich, S. Cierjacks, James A. Bistirlich, W. Dünnweber, K. Braune, R. Beckmann, F. H. Heinsius, C. Völcker, E. Aker, T. Case, R. Hackmann, M. A. Faessler, K. Dederichs, D.V. Bugg, Chr. Strassburger, A. H. Sanjari, Ch. Weddigen, Marcel Kunze, C. Sutton, H. Bossy, P. Blüm, N. P. Hessey, P. Illinger, C. A. Baker, R. Landua, N. Winter, D. Jamnik, U. Wiedner, Michael Doser, D. Engelhardt, W. Schott, U. Strohbusch, J. Lüdemann, Institut de Recherches Subatomiques (IReS), and Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Cancéropôle du Grand Est-Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Photon, Large Hadron Collider, Spectrometer, Meson, Physics::Instrumentation and Detectors, 010308 nuclear & particles physics, 01 natural sciences, Charged particle, Magnetic field, Nuclear physics, Crystal, 0103 physical sciences, Invariant mass, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Detectors and Experimental Techniques, 010306 general physics, Instrumentation
Abstract

The crystal Barrel spectrometer used at LEAR, CERN to study the products of pd annihilations is described. A 1380 element array of Csl crystals measures photons from the decay of π0, η, η′ and ω mesons. A segmented drift chamber in a 1.5T magnetic field is used to identify and measure charged particles. A fast on-line trigger on charged and neutral multiplicities and on the invariant mass of secondary particles is available. The performance of the detector is discussed.

Published
1992

24. Observation of a 2$^{++}$ resonance at 1515 MeV in proton antiproton annihilations into 3$\pi^{0}$

Author

P. Blüm, U. Meyer-Berkhout, P. Birien, K. Königsmann, R. Beckmann, D. Urner, T. Case, R. P. Haddock, I. Augustin, Pàl Hidas, U. Strohbusch, Claude Amsler, P. Illinger, H. Koch, S. Cierjacks, James A. Bistirlich, B. M. Barnett, C. Pegel, C. A. Meyer, Eberhard Klempt, M. Suffert, C. Zupancic, W. Schott, B. Lewendel, M. A. Faessler, K. Peters, H. Bossy, D. Jamnik, L. Montanet, E. Aker, B. Kämmle, C.J. Batty, R. Bossingham, M. Merkel, K. Dederichs, K. Braune, N. Winter, Mark J. Burchell, D. Walther, D. Engelhardt, C.A. Baker, U. Wiedner, S. Ravndal, A. H. Sanjari, R. Landua, C. Felix, Kenneth M. Crowe, G. Folger, N. P. Hessey, H. Matthaey, H. Kalinowsky, W. Dünnweber, E. Schäfer, Bernhard Schmid, T. Kiel, C. Sutton, J. Zoll, S. M. Walther, F. H. Heinsius, and Marcel Kunze

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Proton, Antiproton, Degenerate energy levels, Resonance, Atomic physics, Particle Physics - Experiment
Abstract

Antiproton-proton annihilations at rest into 3 π 0 are analyzed in terms of π 0 π 0 final state interactions. A J PC = 2 + + resonance at a mass of 1515 ± 10 MeV with a width of 120 ± 10 MeV is required to explain the data. This result is supported by previous observations made on the ππ system in p p and p n annihilations which show that the resonance has I = 0. This resonance is practically degenerate in mass with the f′ 2 (1525) but the two resonances have very different production and decay characteristics.

Published
1991

25. Measurement of pion-proton bremsstrahlung for pions at 299 MeV

Author

A. Bosshard, J. F. Loude, Claude Amsler, M. Doser, D. I. Sober, M. Döbeli, Q. Ingram, Kenneth M. Crowe, L. van Elmbt, S. Ljungfelt, R. P. Haddock, J. Riedlberger, J. P. Perroud, D. Renker, C. A. Meyer, M. Schaad, and P. Truol

Subjects
Nuclear reaction, Physics, Particle physics, Pion, Hadron, Elementary particle, Sensitivity (control systems), Atomic physics, Omega, Energy (signal processing), Delta baryon
Abstract

We have measured the fivefold differential cross section ${d}^{5}$\ensuremath{\sigma}/d${\ensuremath{\Omega}}_{\ensuremath{\pi}}$d${\ensuremath{\Omega}}_{\ensuremath{\gamma}}$${\mathrm{dE}}_{\ensuremath{\gamma}}$ for the process ${\ensuremath{\pi}}^{+}$p\ensuremath{\rightarrow}${\ensuremath{\pi}}^{+}$p\ensuremath{\gamma} with incident pions of energy 299 MeV. The angular regions for the outgoing pions (55\ifmmode^\circ\else\textdegree\fi{}\ensuremath{\le}${\ensuremath{\theta}}_{\mathrm{lab}{}^{\ensuremath{\pi}}\mathrm{\ensuremath{\le}}95}$\ifmmode^\circ\else\textdegree\fi{}), and photons (${\ensuremath{\theta}}_{\mathrm{lab}{}^{\ensuremath{\gamma}}=241\mathrm{\ifmmode^\circ\else\textdegree\fi{}}\ifmmode\pm\else\textpm\fi{}10}$\ifmmode^\circ\else\textdegree\fi{}) in coplanar geometry are selected to maximize the sensitivity to the radiation from the magnetic dipole moment of the ${\ensuremath{\Delta}}^{++}$(1232) resonance. At low photon energies, the data agree with the soft-photon approximation to pion-proton bremsstrahlung. At forward pion angles the data agree with older data and with the latest theoretical calculations for 2.3${\ensuremath{\mu}}_{p}$\ensuremath{\le}${\ensuremath{\mu}}_{\ensuremath{\Delta}}$\ensuremath{\le}3.3${\ensuremath{\mu}}_{p}$. However at more backward pion angles where no data existed, the predictions fail.

Published
1988
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27. Positive heavy mesons produced at the Bevatron

Author

E. W. Biege, J. E. Peterson, Marian N. Whitehead, D. H. Stork, L. T. Kerth, R. P. Haddock, and J. Sandweiss

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Angular distribution, Meson, Bevatron, Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics
Abstract

Author(s): Birge, R.W.; Haddock, R.P.; Kerth, L.T.; Peterson, J.R.; Stork, J. Sandweiss D.H.; Whitehead, M.N.

Published
1956
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28. Isospin invariance in the reaction n + p → π° + d

Author

B.L. Schrock, J. A. Helland, R. P. Haddock, K.K. Young, D. Cheng, Victor Perez-Mendez, M. J. Longo, and S. S. Wilson

Subjects
Physics, Nuclear and High Energy Physics, Cross section (physics), Deuterium, Invariance principle, Isospin, Nuclear Theory, Neutron, Atomic physics, Inelastic scattering, Nuclear Experiment, Kinetic energy, Neutron temperature
Abstract

A measurement of the differential cross section for the reaction n+p --*d+ 7r ° has been made using a neutron beam with kinetic energies up to 720 MeV. The angle and momentum of the deuterons were measured using an analyzing magnet and wire spark chambers with a magnetostrietive readout. The photons from the decaying ~o were not detected. The neutron energy was calculated from the measured deuteron angle and momentum. The cross sections are compared to those for the reaction n++d ~ p+p as a test of isotopic spin invariance in strong interactions. The symmetry of the cross sections about 90 ° is also investigated, and an upper limit of about 1% is placed on the real part of the ratio of isospin-violatin g to isospin-conservi ng amplitudes. A measurement of the differential cross sections for the reaction n+p-* d+~ ° has been made at the L. R. L. 184-inch cyclotron with incident neutron energies from threshold to 720 MeV. The results serve as a test of isotopic spin invariance of strong interactions. The experiment was set up primarily to test time reversal invariance in the photodisintegrat ion of the deuteron by measuring the cross section for the reaction n+p~d+v [1], but, with very little extra effort, about 4.5 × 105 events were taken to obtain the n+p~d+~ o cross section. After accidentals were eliminated and fiducial cuts applied, about 2.5× 105 events remained. Half of these events were the desired d+~ ° production with ~1% contamination from the d+7 reaction. The remaining events were from neutron elastic and inelastic scattering.

Published
1971
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29. K+-Meson Branching-Ratio Measurement

Author

Kenneth M. Crowe, M. E. Zeller, N. T. Dairiki, R. L. Beck, J. A. Helland, R. P. Haddock, J. Pahl, and M. T. Maung

Subjects
Physics, Particle physics, Pion, Muon, Meson, Branching fraction, General Physics and Astronomy
Abstract

A measurement of the rates ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}+{\ensuremath{\pi}}^{+}$, ${K}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\pi}}^{0}\ensuremath{\nu}$, and ${K}^{+}\ensuremath{\rightarrow}{e}^{+}+{\ensuremath{\pi}}^{0}+\ensuremath{\nu}$ with respect to ${K}^{+}\ensuremath{\rightarrow}\ensuremath{\mu}+\ensuremath{\nu}$ has been made by using a magnetic spectrometer and spark chambers. Both the range and momentum of the charged decay product are measured and compared with a Monte Carlo calculation. The decay in flight of the ${K}^{+}$ mesons and the scattering of pions into the apparatus are rejected by a decay-time requirement. The results of the branching-ratio measurement are $\ensuremath{\Gamma}({K}_{\ensuremath{\mu}2})=(65.0\ifmmode\pm\else\textpm\fi{}0.9)%$, $\ensuremath{\Gamma}({K}_{\ensuremath{\pi}2})=(19.8\ifmmode\pm\else\textpm\fi{}1.1)%$, $\ensuremath{\Gamma}({K}_{\ensuremath{\mu}3})=(3.5\ifmmode\pm\else\textpm\fi{}0.6)%$, and $\ensuremath{\Gamma}({K}_{e3})=(4.4\ifmmode\pm\else\textpm\fi{}0.4)%$, on the assumptions $\ensuremath{\Gamma}(\ensuremath{\tau})=(5.57\ifmmode\pm\else\textpm\fi{}0.03)%$ and $\ensuremath{\Gamma}({\ensuremath{\tau}}^{\ensuremath{'}})=(1.71\ifmmode\pm\else\textpm\fi{}0.07)%$.

Published
1969
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30. Polarization of 45-MeV Protons by Complex Nuclei

Author

J. Reginald Richardson, Thomas A. Cahill, and R. P. Haddock

Subjects
Materials science, chemistry, Scattering, Aluminium, General Physics and Astronomy, chemistry.chemical_element, Vanadium, Beryllium, Atomic physics, Polarization (waves), Rhodium
Published
1966
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31. A high resolution search for the tensor glueball candidate ξ(2230)

Author

W. Roethel, I. Uman, C.A. Baker, M. Benayoun, P. Kammel, A. Berdoz, B.M. Barnett, H. Matthäy, M. Suffert, Michael Doser, W. Dünnweber, U. Wiedner, U. Thoma, N.P. Hessey, P. Giarritta, B. Kämmle, U. Strohbusch, Č. Zupančič, M. A. Faessler, T. Case, D. Walther, K.M. Crowe, M. Heinzelmann, Kamal K. Seth, M. Ratajczak, L. Montanet, F. Meyer-Wildhagen, R. Landua, C.J. Batty, S. Wallis-Plachner, F. H. Heinsius, K. Peters, C. Regenfus, C. A. Meyer, U. Kurilla, J. S. Suh, M. Lakata, R. P. Haddock, Pàl Hidas, K. Wittmack, D. Jamnik, D. Engelhardt, Herbert Koch, P. Blüm, K. Braune, Claude Amsler, R. Ouared, B. Pick, Jan Kisiel, Eberhard Klempt, H. Kalinowsky, and Marcel Kunze

Subjects
Physics, Nuclear physics, Particle physics, Nuclear and High Energy Physics, Meson, Glueball, Resolution (electron density), Tensor
Abstract

We report results of a high resolution search for the tensor glueball candidate ξ(2230) in a p p formation experiment. π0π0 and ηη decay channels were measured in a scan of the mass region 2220 MeV to 2240 MeV. No evidence for the existence of ξ(2230) was found. 95% confidence upper limits for the possible existence of ξ are presented.

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33. Experiments on the Conservation or Non-Conservation of Isospin, Parity, and Charge Conjugation and Time Reversal Invariance

Author

R. P. Haddock

Subjects
Physics, Conservation law, Electromagnetic interaction, Intermediate energy, Isospin, Quantum mechanics, Hadron, Homogeneous space, Parity (physics)
Abstract

This report concerns mainly some experimental problems related to tests of conservation laws and symmetry principles in intermediate energy physics. The principal symmetries considered are charge independence, CI, charge symmetry, CS, and time reversal invariance, T, in the electromagnetic interaction of hadrons. Tests involving neutral particles in the initial and final states are among the most difficult and will be emphasized. They represent areas in which precise new data would be most welcome. Results of two recent tests, one of charge conjugation invariance, C, and the other on parity, P, conservation in the nucleon-nucleon interaction are also presented.

Published
1978
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34. An Experimental Test of Time-Reversal Invariance in the Photodisintegration of the Deuteron

Author

V. Perez-Mendez, J. F. Detoeuf, S. S. Wilson, M. J. Longo, D. Cheng, B. L. Schrock, K.K. Young, R. P. Haddock, J. A. Helland, and J. Sperinde

Subjects
Nuclear physics, Physics, Normalization (statistics), Angular distribution, Deuterium, Nuclear structure, Inverse, Neutron, Nuclear Experiment, Neutron energy spectrum, Neutron temperature
Abstract

We present data from a measurement of angular distributions of the reaction n + p {yields} {gamma} + d (1a) for neutrons with energies between 300 and 700 MeV. These data are compared with recent data for the inverse reaction {gamma} + d {yields} n + p (1b). Time-reversal invariance implies that apart from a normalization factor the angular distributions should be the same. We find an intriguing discrepancy in the vicinity of the well-known peak in the total cross section of reaction (1b) and apparent agreement elsewhere. The discrepancy occurs in the shape of the angular distributions and does not depend on the normalization of our data or those of the inverse reaction experiments.

Published
1970
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