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W/Z production cross sections

  1. Jul 5, 2013 #1
    I had a look at the production cross sections for W/Z at hadron colliders. These differ as a function of energy with the W x-sec being consistently ~10 times larger than the Z cross sections. Why is the W cross section so much larger? I think the coupling strength is similar and the mass difference is not that large either (~10%).
  2. jcsd
  3. Jul 5, 2013 #2


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    I don't fully understand the reasoning, but this paper gives the ratio as σWZ ≈ 3.33, and this book derives (Eq. 85) the ratio as

    σWZ ~ |Vqq'|2/(vq2 + aq2)

    where Vqq' ≈ 0.97 is the CKM matrix element and aq = 1/2 and vq ≈ -0.3 are the neutral current vector and axial vector couplings.

    Which works out about right.
    Last edited: Jul 5, 2013
  4. Jul 5, 2013 #3

    Vanadium 50

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    What you are probably looking at are not cross-sections but cross-sections times branching fractions.
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