Interaction without T-Channel: S-Channel Only

[touqra]

Just wondering whether there's any interaction, where the t-channel is prohibited, only the s-channel ?

 

[Timo]

If you meant "there is only the s-channel": e+ e- -> tau+ tau-, as one example. A more general class: Every reaction in which the result products do not couple to the incoming particles. Another example (either unfitting or better fitting, depending on what you are looking for): Compton scattering.

 

[sir-pinski]

Yes, there are interactions where the t-channel is prohibited and only the s-channel is allowed. This is commonly seen in particle physics processes, where the t-channel exchange of virtual particles is forbidden due to conservation laws or other theoretical constraints. In these cases, the s-channel becomes the dominant interaction channel and plays a crucial role in the overall process. For example, in the production of electron-positron pairs in high energy collisions, the t-channel exchange of photons is forbidden due to charge conservation, making the s-channel exchange of a Z boson the only possible interaction. Therefore, interactions without a t-channel can still occur and play important roles in various physical processes.