Theory seminar: Goutam Das




"Factorization & Resummation with N-Jettiness"


N-jettiness proves to be an excellent jet-resolution observable that is appealing both theoretically as well as experimentally. In this talk, I will discuss factorization and resummation for the double differential cross-section in the N-jettiness variables Tau1 and Tau0. The phase space spanned by these two variables has different hierarchies between them. This requires different effective theories to describe different regions. After introducing factorization and resummation in the different regions I will focus on the region where Tau1 ~ Tau0 << Q which corresponds to unordered but resolved emissions. Using the power counting argument in SCET, it is possible to separate the collinear and soft contributions which are encoded inside the new beam and soft functions respectively. I will also comment on the structure of these objects as well as on their consistencies and matching with other regions of phase space, in particular, the SCET+ region with strongly ordered emissions.