Production of heavy mesons by Drell-Yan mechanism

We have mentioned that the Drell-Yan analysis above refers to the continuum production of lepton-antilepton pairs, and that any events where the lepton pair originates from a heavy meson resonance should be subtracted out before comparing theory and experiment. We now consider lepton pair production via a resonance. In fact, we have already studied this question in Section 5.3.1 in connection with the production and detection of and in pp collisions, but we then neglected all details of the parton model. 

Then the cross-section can easily be seen to be obtainable from (17.4.33) by the following substitutions  

In Section 5.3.1 we derived a formula for the width of the W+ meson using the couplings appropriate to the WS theory. It is simple to see that 

If we are interested in the production cross-section for the vector mesons (W or Z°) we can treat them as elementary particles, ignoring their width, and replace eqn (17.4.19) by the cross-section for qi +qj — V (averaged over colour) 

The calculation leading to (17.4.40) is the same as that for Fy, aside from phase-space factors. 

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