A new paper, in collaboration with Matteo Cacciari, Michael Czakon, Michelangelo Mangano and Paolo Nason appeared yesterday. I am very excited about it! It has been in the pipeline for a long time and now, looking back, I can definitely say its is a paper that I am very happy with.

The paper fully quantifies the question of how well we know the total inclusive top-pair cross-section at present. In the last few years, results based on the so-called approximate NNLO approach have been explored as a solution to precision top physics. The problem with working with approximations, however, is that one needs to understand the underlying physics very well in order to be able to quantify the full theoretical uncertainty. This is precisely what we have done in this paper.

Our findings are quite natural: based on the soft approximation alone, one does not obtain a significant improvement in the theoretical predictions with respect to the long known NLO/NLL results. The main remaining sensitivity is with resect to the unknown intrinsic NNLO corrections that are beyond any known approximation. Deriving them, and thus settling the outstanding questions in top physics, would require the full NNLO result.

The derivation of the exact NNLO top-pair cross-section is one of my current projects. It is a great problem to work on, especially with a collaborator like Michal Czakon, and I hope to report it very soon. Stay tuned!

In the meanwhile with Michal Czakon we are releasing the program Top++ for the numerical computation of the total inclusive cross-section. The program is the only one publicly available program able to perform soft-gluon approximation in this observable. Please note that, as explained in detail in our new paper, it is much preferred to use the resummed result over the approximate NNLO one.

If you want to give our program Top++ a try, and explore its many options, please visit the program's webpage.