LoopFest XX

Session

Saturday Morning Session 1

14 May 2022, 09:00

Benedum Hall 157 (University of Pittsburgh)

81. The three loop four parton scattering in QCD

Amlan Chakraborty (Michigan State University )

14/05/2022, 09:00

In this talk, I discuss the calculation of all helicity amplitudes for four-parton scattering in three-loop massless QCD. Our results allow us, for the first time, to verify completely the structure of quadrupole IR divergences at this perturbative order in QCD. From the high-energy limit of the amplitudes, we have extracted the three-loop gluon Regge trajectory in full QCD. Our findings...

92. Three-loop helicity amplitudes for diphoton production in gluon fusion

Piotr Bargiela

14/05/2022, 09:25

In this talk, I will present a calculation of the three-loop massless QCD helicity amplitudes for diphoton production in gluon fusion, based on arXiv:2111.13595. I will argue that employing a recently proposed projector method reduces the amount of independent Lorentz tensor structures. I will also discuss the derivation of a complete set of Master Integrals in all the relevant physical...

85. Massive quark form factors at three loops

Fabian Lange (KIT)

14/05/2022, 09:45

I will present our calculation of massive quark form factors at three loops in QCD.
After reducing the Feynman integrals in the amplitudes to master integrals, these were computed by solving differential equations. By constructing expansions around regular as well as singular points and numerical matching, we obtain sufficient precision over the whole kinematic range.

93. On phase-space integrals with Heaviside functions

Daniel Baranowski

14/05/2022, 10:05

In this talk I discuss peculiarities that arise in the computation of real-emission contributions to observables that contain Heaviside functions. Specifically I will discuss the calculation of the zero-jettiness soft function in SCET at next-to-next-to-next-to-leading order in perturbative QCD. The Heaviside functions prevent a direct use of multi-loop methods based on reverse unitarity. I...