Sign up ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free.

In high energy physics there are different channels of particle production: t-channel, s-channel. What do they mean? And are there any other channels besides "t" and "s"?

share|cite|improve this question

1 Answer 1

up vote 3 down vote accepted

These are basically ways of describing which leading diagram contributes the largest term to the cross-section; they are named after which of the Mandelstam variables characterizes the 4-momentum of the virtual particle.

In t- and u-channel processes the 4-momentum of the exchange particle is space-like (has a negative norm).

In the s-channel the 4-momentum of the exchange particle is time-like (has a positive norm). This necessitates the annihilation of the incident particles.

share|cite|improve this answer
Thank you. Now it's more clear to me. – BartoNaz Oct 17 '12 at 13:21

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.