# W/Z production cross sections

1. Jul 5, 2013

### JoePhysicsNut

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. Jul 5, 2013

### Bill_K

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.