# Top quark pair production

1. Dec 8, 2013

### maximus123

Hi there,

My homework problem is on particle physics and asks me to draw a feynman diagram for $pp→\bar{t} t$ interaction, which is what I think the LHC is planning to do (or possibly is doing).

For the more traditional interaction; $\bar{p} p→\bar{t} t$ I have this diagram;

In this case a quark from the proton annihilates with an antiquark of the same flavour in the antiproton into a gluon, which then dissociates into the $\bar{t} t$ pair.

Since in the $pp$ collision there are no antiquarks to annihilate with each other producing the gluon which decays to the top quark pair, how is this step achieved?

Any pointers in the right direction would be greatly appreciated.

Cheers

2. Dec 8, 2013

### maximus123

I imagine that probably there is something that happens that creates the quark anti quark pair which can then annihilate but all I can think of is a W boson decaying but I'm not sure if that is right as I don't think they will be of the same flavour.

Anybody??

3. Dec 8, 2013

### TSny

I'm not very familiar with particle physics, but you might do a search on "gluon fusion" and see if that helps.