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1. Branching ratios for p annihilation at rest into two-body final states

Author

F. H. Heinsius, P. Blüm, D.V. Bugg, U. Strohbusch, C. Straßburger, K. Wittmack, R. Ouared, U. Kurilla, D. Walther, D. Jamnik, J.S. Suh, D. Engelhardt, A. Abele, C.J. Batty, M. A. Faessler, C. Völcker, R.P. Haddock, M. Herz, P. Giarritta, Herbert Koch, Claude Amsler, J. Adomeit, I. Uman, Michael Doser, Marcel Kunze, H. Stöck, A. Herbstrith, C. Holtzhaußen, C. A. Meyer, K. Peters, W. Dünnweber, R. McCrady, M. Lakata, C. Regenfus, J. Kisiel, U. Wiedner, M. Suffert, T. Case, H. Matthäy, B. Pick, P. Kammel, K. Braune, M. Heinzelmann, C.A. Baker, S. Wallis-Plachner, L. Montanet, B.M. Barnett, M. Benayoun, Kenneth M. Crowe, B.S. Zou, H. Kalinowsky, J. Meier, S. Spanier, U. Thoma, C. Hodd, S. Bischoff, Eberhard Klempt, Pàl Hidas, T. Degener, W. Roethel, M. Tischhäuser, M. Ratajczak, N.P. Hessey, and R. Landua

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Hydrogen, chemistry, Branching fraction, Analytical chemistry, chemistry.chemical_element, Atomic physics, Branching (polymer chemistry), Particle Physics - Experiment
Abstract

Measurements of two-body branching ratios for p p annihilations at rest in liquid and gaseous (12 ρ STP ) hydrogen are reported. Channels studied are p p →π 0 π 0 ,π 0 η , K 0 S K 0 L , K + K − . The branching ratio for the π 0 π 0 channel in liquid H 2 is measured to be ( 6.14±0.40)×10 −4 . The results are compared with those from other experiments. The fraction of P-state annihilation for a range of target densities from 0.002 ρ STP to liquid H 2 is determined. Values obtained include 0.11±0.02 in liquid H 2 and 0.48±0.04 in 12 ρ STP H 2 gas.

Published
2001

2. The ρ-mass, width and line shape in annihilation at rest into π+π−π0

Author

H. Stöck, W. Roethel, P. Blüm, Herbert Koch, F. H. Heinsius, D.V. Bugg, M. Heinzelmann, U. Strohbusch, C. Straßburger, K. Braune, S. Wallis-Plachner, S. Bischoff, A. Ehmanns, C. Holtzhaußen, A. Herbstrith, O. Cramer, D. Walther, A. Berdoz, K. Wittmack, C.J. Batty, R. Ouared, Claude Amsler, Eberhard Klempt, Michael Doser, V. Crede, W. Dünnweber, U. Kurilla, J. Adomeit, K. Peters, T. Case, H. Matthäy, J. Kisiel, U. Wiedner, I. Uman, C. A. Meyer, C.A. Baker, P. Kammel, Stefan M Spanier, M. Lakata, Kenneth M. Crowe, B.M. Barnett, U. Thoma, C. Hodd, B. Pick, M. A. Faessler, R.P. Haddock, D. Jamnik, T. Degener, B.S. Zou, D. Engelhardt, C. Regenfus, M. Herz, H. Kalinowsky, J. Meier, Pàl Hidas, P. Giarritta, R. McCrady, J.S. Suh, R. Landua, M. Suffert, C. Völcker, A. V. Anisovich, Marcel Kunze, M. Ratajczak, M. Tischhäuser, N.P. Hessey, and A. Abele

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Nuclear magnetic resonance, Annihilation, Hadron physics, Pi, Line (formation), Bar (unit)
Abstract

The rho mass, width and line shape in p(over)-bar-p annihilation at rest into pi(+)pi(-)pi(0)

Published
1999

3. annihilation at rest into π+π−π−pspectator

Author

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

Subjects
Rest (physics), Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Partial wave analysis, Pi
Published
1999

4. Evidence for a πη-P-wave in -annihilations at rest into π0π0η

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Protonium, Cascade, Partial wave analysis, P wave, Mass spectrum, Resonance, Dalitz plot, Atomic physics
Abstract

A partial wave analysis is presented of two high-statistics data samples of protonium annihilation into π 0 π 0 η in liquid and 12 atm gaseous hydrogen. The contributions from the 1 S 0 , 3 P 1 and 3 P 2 initial atomic fine structure states to the two data sets are different. The change of their fractional contributions when going from liquid to gaseous H 2 as calculated in a cascade model is imposed in fitting the data. Thus the uncertainty in the fraction of S-state and P-state capture is minimized. Both data sets allow a description with a common set of resonances and resonance parameters. The inclusion of a π η P-wave in the fit gives supportive evidence for the ρ (1405) , with parameters compatible with previous findings.

Published
1999

5. p¯pannihilation at rest intoKLK±π∓

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Crystallography, Annihilation, Branching fraction, Partial wave analysis, Pi, Dalitz plot, K matrix
Abstract

We present a measurement and partial wave analysis of the final state ${K}_{L}{K}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\pi}}^{\ensuremath{\mp}}$ of $\overline{p}p$ annihilation at rest in liquid hydrogen. This reaction is important for the study of the $\overline{K}K$ decay mode of scalar resonances, in particular, the isovectors ${a}_{0}(980)$ and ${a}_{0}(1450).$ The determination of the ${a}_{0}(1450)$ production also fixes the $\overline{K}K$ coupling of the isoscalar ${f}_{0}(1500)$ which is discussed as a glueball. We find $B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{a}_{0}(1450)\ensuremath{\pi}{;a}_{0}(1450)\ensuremath{\rightarrow}\overline{K}K)=(8.88\ifmmode\pm\else\textpm\fi{}1.68)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and hence $B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{f}_{0}(1500)\ensuremath{\pi}{;f}_{0}(1500)\ensuremath{\rightarrow}\overline{K}K)=(4.52\ifmmode\pm\else\textpm\fi{}0.36)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}.$ The mass and width of ${a}_{0}(1450)$ are $m=1480\ifmmode\pm\else\textpm\fi{}30\mathrm{MeV}{/c}^{2}$ and $\ensuremath{\Gamma}=265\ifmmode\pm\else\textpm\fi{}15\mathrm{MeV}{/c}^{2},$ respectively. For ${a}_{0}(980)$ we determine the relative ratio $B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{a}_{0}\ensuremath{\pi}{;a}_{0}\ensuremath{\rightarrow}\overline{K}K)/B(\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}{a}_{0}\ensuremath{\pi}{;a}_{0}\ensuremath{\rightarrow}\ensuremath{\pi}\ensuremath{\eta})$ =0.23\ifmmode\pm\else\textpm\fi{}0.05 and its relative coupling, $\overline{K}K$ to \ensuremath{\pi}\ensuremath{\eta}, is $1.03\ifmmode\pm\else\textpm\fi{}0.14.$

Published
1998

6. Exotic ηπ state in annihilation at rest into π−π0η pspectator

Author

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

Subjects
Nuclear physics, Momentum, Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Deuterium, Proton, Antiproton, Resonance, Dalitz plot, Quantum number
Abstract

With antiprotons stopped in liquid deuterium, the p n annihilation channel π−π0η was studied using a final sample of 52 576 events obtained for a spectator proton momentum q q quantum numbers IG=1−, JPC=1−+. The extracted Breit-Wigner resonance parameters are m=(1400±20±20) MeV/c2 and Γ=(310±50+50−30) MeV/c2.

Published
1998

7. 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

8. 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

9. Antiproton-proton annihilation at rest into KK±π∓π - manifestations of isospin interference

Author

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

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Amplitude, Antiproton, Isospin, Strangeness
Abstract

The decay p p ( at rest ) → K L o K ± π ∓ π o , studied on a sample of more than 14000 events, is found to proceed dominantly via two-body channels containing resonances with open strangeness. Contributions from K 1 (1270) K and K 1 (1400) K , branching into the successive K1-decay modes, and from K ∗ K ∗ , K ∗ ( K π) s and (Kπ) s ( K π) s are extracted by means of a partial-wave analysis which accounts well for the data and also allows a search for weak contributions from other (Kππ) and from ( K K π ) resonances. Striking asymmetries between the charged and the neutral kaonic resonances give evidence for interfering isospin 0 and 1 annihilation amplitudes.

Published
1997

10. Antiproton-proton annihilation at rest into KKπ0π0

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Annihilation, Proton, 010308 nuclear & particles physics, Branching fraction, Partial wave analysis, Dalitz plot, 01 natural sciences, Crystal, Nuclear physics, Angular distribution, Antiproton, 0103 physical sciences, Atomic physics, 010306 general physics
Abstract

The annihilation channel p p →K + K − π 0 in liquid hydrogen at rest has been studied with the Crystal Barrel detector at LEAR. The measured branching ratio is: BR ( p p → K + K − π 0 )=(2.37±0.15)×10 −3 . A partial wave analysis shows that this reaction is dominated by the π (K K ) S , K K ∗ (892) and π φ (1020) intermediate states. Weak signals are observed for π a 2 (1320), π f 2 (1270), π f 2 ′(1525) and K(Kπ) S . A satisfactory description of the Dalitz plot requires the introduction of π (K K ) P intermediate states with at least one pole.

Published
1997

11. 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

12. ϱ-ω interference in p-annihilation at rest into π+π−η

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Amplitude, Annihilation, Meson, Invariant mass, Atomic physics, Coherence (physics)
Abstract

The π + π − invariant mass distribution produced in p p annihilation at rest and recoiling against η mesons exhibits large interference between the amplitudes for ϱη and ωη production. The interference can be quantitatively described within the framework of ϱ-ω interference. We find full coherence between the ϱω-ωη production amplitudes and a vanishing relative production phase. The implications of this result for p p annihilation dynamics are discussed.

Published
1997

13. 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

14. Measurement of the decay distribution of η′ → π+π−γ and evidence for the box anomaly

Author

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

Subjects
Pseudoscalar, Physics, Nuclear physics, Quantum chromodynamics, Crystal, Nuclear and High Energy Physics, Distribution (mathematics), Anomaly (physics), Atomic physics, Constant (mathematics)
Abstract

The distribution of m ( π + π − ) in the decay η ′ → π + π − γ has been measured with the Crystal Barrel detector. The results are based on a total of 7392 observed η′ decays. The box anomaly constant is extracted from this and its value is found to agree well with theoretical expectations. The pseudoscalar nonet parameters ( f 1 , f 8 and θ PS ) are determined. Finally, we find that there is a problem of consistency between QCD and the standard VDM assumption.

Published
1997

15. High-mass ϱ-meson states from p̄d-annihilation at rest into π−π0π0pspectator

Author

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

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Annihilation, Meson, Deuterium, Partial wave analysis, High mass, Neutron, Atomic physics
Abstract

A study of p -annihilation in liquid deuterium into π − π 0 π 0 and a spectator-proton is presented. A cut on the proton-momentum of ≤ 100 MeV/ c ensures that annihilation takes place on a quasi-free neutron. A partial wave analysis shows contributions from three vector mesons, with masses and widths of (763.7 ± 3.2; 152.8 ± 4.3), (1411 ± 14; 343 ± 20); (1780 −29 +37 ; 275 ± 45) MeV/ c 2 , respectively.

Published
1997

16. A study of f0(1500) decays into 4π0 in at rest

Author

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

Subjects
Crystal, Physics, Rest (physics), Nuclear and High Energy Physics, Angular distribution, Amplitude, Phase space, Mass spectrum, Atomic physics
Abstract

Crystal Barrel data on p p → 5π 0 at rest are presented. Mass spectra for 2π0 combinations, 3π0 and 4π0 and decay angular distributions all differ significantly from phase space. We present several ways of fitting the data. All agree on the definite presence of the f0(1500), observed in its 4π0 decay mode. It can decay into ππ(1300) and into σσ where σ stands for the full ππ S-wave amplitude.

Published
1996

17. Evidence for two isospin zeroJ PC=2−+ mesons at 1645 and 1875 MeV

Author

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

Subjects
Nuclear physics, Physics, Physics and Astronomy (miscellaneous), Meson, Isospin, Zero (complex analysis), High mass, Dalitz plot, Resonance, Atomic physics, Rest frame, Bar (unit)
Abstract

Data on\(\bar pp \to \eta \pi ^0 \pi ^0 \pi ^0 \) taken at beam momenta of 1.2 and 1.94 GeV/c reveal evidence for twoI=0JPC=2−+ resonances inηππ. The first, at 1645±14(stat.)±15(syst.) MeV with width 180−21+40±25 MeV, decays toα2(1320)π withL=0. It may be interpreted as the\(q\bar q^1 \)D2 partner ofπ2(1670). A strong signal is also observed just above threshold inf2(1270)η withL=0. It is 11–22 times stronger than is expected for the high mass tail of the 1645 MeV resonance. It can be fitted as a second 2−+ resonance at 1875±20±35 MeV with width 200±25±45 MeV. A third resonance havingJPC=2++ is observed at 2135±20±45 MeV withΛ=250±25±45 MeV, decaying to botha2(1320)π andf2(1270)η withL=1. There is no evidence for resonances with decays toa0(980)π, ση orf0(980)η.

Published
1996

18. E decays to ηππ in annihilation at rest

Author

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

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Angular distribution, Annihilation, Meson, Branching fraction, Isoscalar, Mass spectrum
Abstract

We have observed the ηπ + π − and ηπ 0 π 0 decay modes of the E meson in p p annihilation at rest into π + π − π 0 π 0 η . The mass and width of the E meson are 1409 ± 3 and 86 ± 10 MeV. The production and decay branching ratio is B( p p → Eππ)B(E → ηππ) = (3.3 ± 1.0) × 10 −3 . With a spin-parity analysis we determine that J P = 0 − . The observation of the ηπ 0 π 0 decay mode establishes that E is isoscalar ( C = +1). We find that E decays to η ( ππ ) s (where ( ππ ) s is an S-wave dipion) and πa 0 (980)(→ πη ) with a relative branching ratio of (78 ± 16) %. Using the K K π production and decay branching ratio measured earlier we determine that B[E → K K π] B[E → ηππ] = 0.61 ± 0.19 . A comparison with observations in radiative J Ψ decays suggests that E and ι η (1416) are identical.

Published
1995

19. 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

20. High statistics study of ƒ0(1500)s decay into ηη

Author

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

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Quality (physics), Partial wave analysis, Scalar (mathematics), Statistics, Dalitz plot, Resonance
Abstract

A partial wave analysis of the reaction p p →π o ηη has been performed, using a high quality, high statistics data set of 198,000 events. In addition to the ƒ 0 (1370), a second scalar resonance decaying into ηη, the ƒ 0 (1500), with mass m = (1505 ± 15) MeV and width Γ = (120 ± 30) MeV has to be introduced to describe the data.

Published
1995

21. 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

22. η-decays into three pions

Author

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

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Crystallography, Chiral perturbation theory, Pion, Partial width, Mass spectrum, Dalitz plot
Abstract

The branching ratios Γ(η → 3π 0 ) Γ(η → π + π − π 0 ) = 1.44 ± 0.09 ± 0.10 and Γ(η → γγ) Γ(η → π + π − π 0 ) = 1.78 ± 0.10 ± 0.13 have been determined using the Crystal Barrel detector at LEAR. The latter ratio yields a partial width of Γ ( η → π + π − π 0 ) = 0.26 ± 0.03 keV using the known value for Γ ( η → γγ ). The η → π + π − π 0 ) Dalitz plot is compared to the predictions of chiral perturbation theory.

Published
1995

23. Observation of radiative annihilation into a Φ meson

Author

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

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Annihilation, Meson, Antiproton, Branching fraction, Radiative transfer, Analytical chemistry
Abstract

The annihilation p p → Φγ has been investigated with the Crystal Barrel detector at LEAR for antiprotons stopped in liquid hydrogen. The observed branching ratio BR ( p p → Φγ = (1.7 ± 0.4) · 10 −5 is almost two orders of magnitude higher than expected from the OZI-rule. As a by-product, the branching ratios BR ( p p → K L K S ) = (9.0 ± 0.6) · 10 −4 and BR ( p p → Φπ 0 ) = (5.5 ± 0.7) · 10 −4 have been measured.

Published
1995

24. 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

25. New analysis of the radiative decayω→ηγin proton-antiproton annihilation at rest

Author

C. Kolo, C.A. Baker, Kenneth M. Crowe, J.S. Suh, B.S. Zou, H. Kalinowsky, J. Meier, W. Roethel, F. H. Heinsius, K. Peters, C. Völcker, S. Bischoff, U. Wiedner, C. Straßburger, D. Jamnik, M. Ratajczak, D. Engelhardt, R. Landua, Marcel Kunze, R. Ouared, U. Kurilla, A. Abele, S. Wallis-Plachner, C.J. Batty, B. M. Barnett, B. Pick, M. Suffert, R. Seibert, M. Lakata, I. Uman, M. A. Faessler, T. Degener, R.P. Haddock, P. Kammel, A. Herbstrith, Pàl Hidas, M. Herz, D. Walther, T. Case, H. Matthäy, K. Wittmack, J. Kisiel, U. Thoma, C. Hodd, H. Stöck, C. Holtzhaußen, K. Braune, U. Strohbusch, W. Dünnweber, R. McCrady, J. Adomeit, Michael Doser, Nigel Hessey, M. Tischhäuser, P. Blüm, D.V. Bugg, Herbert Koch, Eberhard Klempt, A. Berdoz, and C. A. Meyer

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Annihilation, Proton, Antiproton, Branching fraction, High Energy Physics::Phenomenology, Radiative transfer, Radiative decay, Degree of coherence, Omega
Abstract

We report on a measurement of the branching ratio of the rare decay $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\omega}}\ensuremath{\eta}\ensuremath{\gamma}$ relative to the well known decay $\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\omega}}{\ensuremath{\pi}}^{0}\ensuremath{\gamma}.$ The \ensuremath{\omega}'s are produced in $p\overline{p}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\omega}$ and $p\overline{p}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}\ensuremath{\omega}.$ Eigenstate mixing and interference effects of the \ensuremath{\omega} and ${\ensuremath{\rho}}^{0}$ are taken into account, as well as coherent interference with the background. We find evidence for the non-resonant annihilation channel $B(p\overline{p}\ensuremath{\rightarrow}\ensuremath{\eta}\ensuremath{\eta}\ensuremath{\gamma})=(3.5\ifmmode\pm\else\textpm\fi{}1.3)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and limit the value of $B(\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\omega}}\ensuremath{\eta}\ensuremath{\gamma})$ to the range of $(0.7\mathrm{to}5.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ depending on the degree of coherence with the background.

Published
2000

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