Evidence for chain - like production of strange baryon pairs in jets

The production dynamics of baryon-antibaryon pairs are investigated using hadronic Z 0 decays, recorded with the OPAL detector, which contain at least two identified Λ baryons. The rapidly difference for Λ Λ pairs shows the correlations expected from models with a chain-like production of baryon-antibaryon pairs. If the baryon number of a Λ is compensated by a Λ , the Λ is found with a probability of 53% in an interval of ±0.6 around the Λ rapidity. This correlation strength is weaker than predicted by the Herwig Monte Carlo and the Jetset Monte Carlo with a production chain of baryon-antibaryon, and stronger than predicted by the UCLA model. The observed rapidity correlations can be described by the Jetset Monte Carlo with a dominant production chain of baryon-meson-antibaryon, the popcorn mechanism. In addition to the short range correlations, one finds an indication of a correlation of Λ Λ pairs in opposite hemispheres if both the Λ and the Λ have large rapidities. Such long range correlations are expected if the primary quark flavours are compensated in opposite hemispheres and if these quarks are found in energetic baryons. Rates for simultaneous baryon and strangeness number compensation for Λ Λ , Ξ − Ξ + and Ξ − Λ ( Λ + Λ ) are measured and compared with different Monte Carlo models.

electron positron: colliding beams
colliding beams: electron positron
electron positron: annihilation
annihilation: electron positron
Z0: electroproduction
electroproduction: Z0
Z0: nonleptonic decay
nonleptonic decay: Z0
jet
hyperon: pair production

References(21)

Figures(0)

Parton Fragmentation and String Dynamics

- Phys.Rept. 97 (1983) 31-145
•
DOI:
- 10.1016/0370-1573(83)90080-7

The Lund Monte Carlo for Jet Fragmentation and e+ e- Physics: Jetset Version 6.2

Torbjorn Sjostrand
(
- Lund U., Dept. Theor. Phys.
)

- Comput.Phys.Commun. 39 (1986) 347-407
•
DOI:
- 10.1016/0010-4655(86)90096-2

The Lund Monte Carlo for Jet Fragmentation and e+ e- Physics. Jetset Version 6.3: An Update

- Comput.Phys.Commun. 43 (1987) 367
•
DOI:
- 10.1016/0010-4655(87)90054-3

The Structure of Jets in $e^+ e^-$ Collisions

Peter Mattig
(
- IPP, Canada and
- Carleton U.
)

- Phys.Rept. 177 (1989) 141
•
DOI:
- 10.1016/0370-1573(89)90057-4

Baryon Production in Jet Fragmentation and $\Upsilon$ Decay

- Phys.Scripta 32 (1985) 574
•
DOI:
- 10.1088/0031-8949/32/6/003

Baryon Production in e+ e- Annihilation at PETRA

JADE

Collaboration

•

W. Bartel
(
- DESY
)

et al.

- Phys.Lett.B 104 (1981) 325-329
•
DOI:
- 10.1016/0370-2693(81)90135-0

Charged Hadron Composition of the Final State in e+ e- Annihilation at High-Energies

TASSO

Collaboration

•

M. Althoff
(
- Aachen, Tech. Hochsch.
)

et al.

- Z.Phys.C 17 (1983) 5-15
•
DOI:
- 10.1007/BF01577813

A Detailed Study of Strange Particle Production in $e^+ e^-$ Annihilation at High-energy

TASSO

Collaboration

•

M. Althoff
(
- Aachen, Tech. Hochsch.
)

et al.

- Z.Phys.C 27 (1985) 27,
- Z. Phys. C27 ( 1985) 27-37 and Hamburg Desy - DESY 84-093 (84,REC.OCT.) 34p
•
DOI:
- 10.1007/BF01642477

Evidence for Local Compensation of Baryon Number in $e^+ e^-$ Annihilation

TASSO

Collaboration

•

M. Althoff
(
- Aachen, Tech. Hochsch.
)

et al.

- Phys.Lett.B 139 (1984) 126-132
•
DOI:
- 10.1016/0370-2693(84)90047-9

Observation of strangeness correlations in $e^+e^-$ annihilation at $\sqrt{s} = 29$ GeV

TPC/Two Gamma

Collaboration

•

H. Aihara

et al.

- Phys.Rev.Lett. 53 (1984) 2199,
- Phys. Rev. Lett. 53 (1984) 2199-2202 and Lawrence Berkeley Lab. - LBL-18125 (84,REC.NOV.) 19p
•
DOI:
- 10.1103/PhysRevLett.53.2199