LoopFest XXI

Session

Session 3

26 Jun 2023, 14:00

Kavli Auditorium (SLAC National Accelerator Laboratory)

Conveners

Session 3: Afternoon Session 1

• Alessandro Vicini (Università degli Studi e INFN Milano (IT))

Session 3: Afternoon Session 3

• Fernando Febres Cordero

Session 3: Afternoon Session 5

• Sally Dawson (BNL)

2. Three-Loop Scattering Amplitudes in full color QCD: results in the IR and Regge limit.

Giulio Gambuti

26/06/2023, 14:00

I will describe the methods used for the first computation of three-loop QCD scattering amplitudes involving four external massless partons in full color complexity. These calculations require careful management of color structures and, more importantly, of the large numbers of Feynman integrals induced by the Feynman rules of the theory. The resulting amplitudes result allowed a direct...

45. On the evaluation of three-loop non-planar Feynman diagrams for Higgs plus jet production

Dr William J. Torres Bobadilla (Max-Planck-Institute for Physics)

26/06/2023, 14:25

23. Master Integrals for Electroweak corrections to gg → γγ

Gabriele Fiore (SUNY Buffalo)

26/06/2023, 14:50

We present a calculation of the master integrals (MI's) required for the calculation of the Electroweak corrections to $gg\rightarrow \gamma\gamma$ production in which the process contains a light quark loop.
The integrals can be broken down into four categories based on the flow of the heavy vector bosons throughout the loop. Two of the families are planar, and two are non-planar. We...

7. Interference studies in Higgs to gamma gamma

Federica Devoto

27/06/2023, 14:00

In this talk I will present results for the interference between higgs-mediated diphoton production and its continuum background at the LHC. We compute the total cross section at NNLO QCD in the soft-virtual approximation and in particular we focus on the diphoton invariant mass distribution. Following up on previous literature, we exploit the shift in the diphoton invariant mass induced by...

24. Non-planar two-loop QCD corrections to $q\bar q \rightarrow \gamma\gamma\gamma$: finite remainders in the spinor-helicity formalism

Dr Giuseppe DeLaurentis (Paul Scherrer Institut)

27/06/2023, 14:25

I will present the computation of the NNLO double-virtual subleading-color corrections to the production of three photons at hadron colliders. I will briefly review the numerical generalized unitarity computation over finite fields performed with the C++ code Caravel, including updates that made this computation possible. I will then formulate the rational reconstruction problem for the finite...

22. Five-point QCD amplitudes in full colour

Federico Buccioni, Federico Buccioni

27/06/2023, 14:50

In this talk I will present recent developments on the calculation of five-point scattering amplitudes in massless QCD beyond the leading-colour approximation.
I will discuss the methodology that we pursued to compute these highly non-trivial amplitudes. In this respect, I will argue that it is possible to tackle and tame the seemingly intractable algebraic complexity at each step of the...

19. Towards NNLO QCD corrections for the production of a heavy-quark pair in association with a massive boson

Chiara Savoini

27/06/2023, 15:15

In the past few years, remarkable progresses in multi-loop calculations have opened the doors to the computation of massless two-loop five-point scattering amplitudes, allowing to complete NNLO QCD predictions for complicated $2 \rightarrow 3$ processes like tri-photon, tri-jet and di-photon plus jet production. Very recently, also the two-loop five-point scattering amplitudes with one...

3. Two-Loop Electroweak Corrections with Fermion Loops to e^+e^- to ZH

Qian Song

28/06/2023, 14:00

Motivated by the anticipated high precision for the measurement of the cross section of e^+e^- to ZH process, we present a complete calculation of the next-to-next-to-leading (NNLO) electroweak corrections involving closed fermion loops. This has been achieved by using a semi-numerical technique for the two-loop vertex and box diagrams, which is based on Feynman parameters and dispersion...

18. Three-point energy correlator in N=4 and QCD

Xiaoyuan Zhang (Harvard University)

28/06/2023, 14:25

We present the analytic result of three-point energy correlator in N=4 SYM and QCD. This is the first analytic computation of trijet event shape observables, which provides precise data for both theoretical analysis and phenomenological studies in jet substructure. The beauty of energy correlator allows us to rationalize all square roots and finish the full four-particle phase space integral....

5. Two-loop mixed QCD-electroweak amplitudes for Z+jet production

Piotr Bargiela

28/06/2023, 14:50

In this talk, I will present a calculation of the two-loop mixed QCD-electroweak amplitudes for Z+jet production in proton colliders. I will argue that employing a recently proposed projector method reduces the amount of independent Lorentz tensor structures. I will discuss the numerical evaluation of multi-scale Feynman integrals with the Auxiliary Mass Flow method. Finally, I will mention...

9. Two-loop non-planar master integrals for four-point massless scattering with top quark loop

Dr Taushif Ahmed (University of Regensburg)

In my talk, I will discuss the analytical results for a non-planar family of master integrals appearing in NNLO 2-loop diagrams of scattering amplitudes of diphoton and dijet production processes. We use the method of differential equations keeping the full dependence on the top quark's mass running in the loop to obtain the results for these master integrals up to O(\epsilon^4). The top...