Abstract
We discuss the possibility of colour rearrangement in\(e^ + e^ - \to W^ + W^ - \to q_1 \bar q_2 q_3 \bar q_4 \) events, i.e that the original colour singlets\(q_1 \bar q_2 \) and\(q_3 \bar q_4 \) may be transmuted, for instance, into new singlets\(q_1 \bar q_4 \) and\(q_3 \bar q_2 \). 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, theW + andW − usually decay at separately. We argue that such a scenario is unlikely for two reasons. Firstly, theW + 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 α 2s 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 LEP 2 events are illustrated, with special attention to systematic errors inW mass determinations.
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Sjöstrand, T., Khoze, V.A. On colour rearrangement in hadronicW +W− evemts. Z. Phys. C - Particles and Fields 62, 281–309 (1994). https://doi.org/10.1007/BF01560244
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DOI: https://doi.org/10.1007/BF01560244