On Color rearrangement in hadronic W+ W- events

Oct, 1993
63 pages
Published in:
  • Z.Phys.C 62 (1994) 281-310
e-Print:
Report number:
  • CERN-TH-7011-93,
  • DTP-93-74

Citations per year

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Abstract: (CERN)
We discuss the possibility of colour rearrangement in \ee \to \W~+ \W~- \to \q_1 \qbar_2 \q_3 \qbar_4 events, i.e.\ that the original colour singlets \q_1 \qbar_2 and \q_3 \qbar_4 may be transmuted, for instance, into new singlets \q_1 \qbar_4 and \q_3 \qbar_2. The effects on event properties could be quite large if such a rearrangement would occur instantaneously, so that gluon emission would be restricted to each of the new singlets separately. We argue that such a scenario is unlikely for two reasons. Firstly, the \W~+ and \W~- usually decay at separate times after the \W~+\W~- production, which leads to large relative phases for energetic radiation off the two constituents of a rearranged system, and a corresponding dampening of the QCD cascades. Secondly, within the perturbative scenario the colour transmutation appears only in order αs 2\alpha_s~2 and is colour-suppressed. Colour reconnection at longer time scales is quite feasible, however, and may affect the fragmentation phase. If so, the nature of non-perturbative QCD can be probed in a new way. We formulate several alternative toy models and use these to estimate the colour reconnection probability as a function of the event kinematics. Possible consequences for LEP2 events are illustrated, with special attention to systematic
  • electron positron: annihilation
  • annihilation: electron positron
  • W: pair production
  • pair production: W
  • W: electroproduction
  • electroproduction: W
  • W: nonleptonic decay
  • nonleptonic decay: W
  • final state: (2quark 2antiquark)
  • (2quark 2antiquark): final state