Abstract
We study ππ correlations in the exclusive reaction \(\bar pp \to 2\pi ^ + 2\pi ^ - \pi ^0 \) at rest with complete reconstruction of the kinematics for each event. Inclusive and differential distributions properly normalized show an enhancement for small invariant masses M ++,M -- of like-pion pairs. An even stronger enhancement is seen for the double differential distributions for low pion-pair masses. The signal is strongest when the π0 energy is large and much weaker when this energy is small. Dynamical models with resonances in the final state are confronted with the data. For the kinematic situation where the ρ3π channel is important the simulation predicts a large pion correlation for the double differential density, qualitatively explaining the observed bahaviour. The stochastic HBT mechanism is not supported by these findings for the exclusive annihilation reaction studied.
Similar content being viewed by others
References
A. Angelopoulos et al., CPLEAR Collaboration, Europ. Phys. J. Cl (1998) 139
R. Hanbury-Brown, R.Q. Twiss, Phil. Mag. 45, 633 (1954)
G. Goldhaber et al., Phys. Rev. Lett. 3, 181 (1959); G. Goldhaber et al., Phys. Rev. 120, 300 (1960)
G. Cocconi, Phys. Lett. B 49, 459 (1974)
G.I. Kopylov, M.Y. Podgoretskii, Sov. J. Nucl. Phys. 19, 215 (1974)
R. Adler et al., CPLEAR Collaboration, Phys. Lett. B 267, 154 (1991); R. Adler et al., CPLEAR Collaboration, Z. Phys. C 65, 199 (1995)
R. Adler et al., CPLEAR Collaboration, Nucl. Instrum. Methods A 379, 76 (1996)
R. Adler et al., CPLEAR Collaboration, Z. Phys. C 63, 541 (1994)
M. Deutschmann et al., Nucl. Phys. B 204, 333 (1982)
S. Ahmad et al., Proc. IV LEAR Workshop, Villars (1987) 697, edited by C. Amsler, G. Backenstoss, R. Klapisch, C. Leluc, D. Simon, L. Tauscher
K. Sarigiannis et al., Nucl. Phys. A 558, 43c (1993)
M. Gaspero, Nucl. Phys. A 588, 861 (1995); A 614, 565 (1997)
M. Gaspero, A. De Pascuale, Phys. Lett. B 358, 146 (1995)
P. Annios et al., Phys. Rev. 20, 402 (1968)
H.Q. Song, B.S. Zou, M.P. Locher, J. Riedlberger, P. Truöl, Z. Phys. A 342, 439 (1992)
M.P. Locher, V.E. Markushin, H.Q. Zheng, Phys. Rev. D 55 (1997) 2894
A. Breakstone et al., Phys. Lett. B 162, 400 (1985)
T. Alexopoulos et al., Phys. Rev. D 48, 1931 (1993)
P. Abreu et al., DELPHI Collaboration, Z. Phys. C 63, 17 (1994)
T. Akesson et al., Phys. Lett. B 129, 269 (1983)
T. Akesson et al., Phys. Lett. B 187, 420 (1987); T. Akesson et al., Z. Phys. C 36, 517 (1987)
C. Albajar et al., Phys. Lett. B 226, 410 (1989)
N. Neumeister et al., Phys. Lett. B 275, 186 (1992)
N. Neumeister et al., Z. Phys. C 60, 633 (1993)
T.C. Awes et al., Z. Phys. C 69, 67 (1995)
Author information
Authors and Affiliations
Consortia
Rights and permissions
About this article
Cite this article
CPLEAR Collaboration., Apostolakis, A., Aslanides, E. et al. Pion correlations and resonance effects in \(\bar pp\) annihilation at rest to 2π+2π-π0 . Eur. Phys. J. C 6, 437–450 (1999). https://doi.org/10.1007/s100529801032
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s100529801032