### Conveners

#### Parallel Session 2: QCD

- James Whitehead (IPPP, Durham)

#### Parallel Session 2: Quantum gravity 2

- Alastair Stewart (Durham University)

The laws of physics should not depend on how we choose to describe them, and we should not be able to change the physical predictions of our theory just by changing notation. However, this is exactly what happens in the standard formulation of quantum field theories. The effective action receives different quantum corrections depending on how we parametrise our fields. Even Feynman diagrams, a...

QCD coherence is a non-Abelian generalisation of the statement that short wavelength physics is largely independent of long wavelength physics. The evolution of hadronic parton densities is accounted for using the equations of Dokshitzer, Gribov, Lipatov, Altarelli, and Parisi (DGLAP). It is often assumed that, as a result of QCD coherence, this hadron evolution can be factorised from any...

Studying field theory in de Sitter spacetime is important because of its relevance to inflationary cosmology. N-dimensional de Sitter space can be obtained by analytic continuation of the N-sphere. In this talk, I will discuss how one can construct spinor fields in de Sitter spacetime by analytically continuing the eigenfunctions of the Dirac operator on the N-dimensional sphere. Furthermore,...

The aim is to explain what the soft anomalous dimension is and its relevance to computing cross sections. Scattering amplitudes can be factorised into hard, soft and jet functions. The soft function renormalisation group equation defines the soft anomalous dimension and the its constrains will be discussed.

In high energy particle collisions, large logarithms appear at all

orders in the coupling of fixed-order perturbative calculations.

I will introduce the High Energy Jets formalism which incorporates these large logarithms to all orders in the coupling. In particular, I will talk about our current effort to match this prediction to next-to-leading order accuracy.