Loops and Legs in Quantum Field Theory

Session

Parallel 6

18 Apr 2024, 09:00

Martin Luther

Conveners

Parallel 6

• Roberto Bonciani (Sapienza Universita' di Roma, Roma, Italy)

Parallel 6

• Roberto Bonciani (Sapienza Universita' di Roma, Roma, Italy)

77. Resummed predictions for differential rates of inclusive B-meson decays.

Ivan Novikov (KIT)

18/04/2024, 09:00

The smallest element of the CKM matrix, $|V_{ub}|$, can be extracted from measurements of semileptonic B meson decay $B\to X_ul\bar{\nu}$. However, the experimental signal of this process is obscured by large background $B\to X_cl\bar{\nu}$.
This background is kinematically forbidden at the edge of the phasespace, but this region is sensitive to nonperturbative effects. Factorization theorems...

66. Nonleptonic B decays at NNLO

Manuel Egner

18/04/2024, 09:30

The decay of B mesons can be predicted within the Heavy Quark Ex-
pansion as the decay of a free bottom quark plus corrections which are
suppressed by powers of 1/𝑚𝑏. This talk will describe the calculation
of the NNLO corrections to nonleptonic decays of a free bottom quark
including charm quark mass effects. In particular we will describe
challenges in connection to the computation of...

22. Renormalization with non-anticommuting gamma5 applied to the SM and related theories

Dominik Stöckinger (TU Dresden)

18/04/2024, 10:00

Chiral gauge theories such as the electroweak SM involve the gamma5 matrix which cannot be defined in dimensional regularization without breaking important properties. The rigorouse t Hooft/Veltman/Breitenlohner/Maison scheme gives up anticommutativity of gamma5. As a result, gauge invariance is broken. In our research programme we determine the required gauge-invariance restoring...

72. N3LO corrections to zero-jettiness soft function

Andrey Pikelner (KIT TTP)

18/04/2024, 11:00

We discuss the analytical computation of N3LO corrections to zero-jettiness soft function in QCD. We present the results of triple emission contribution together with one-loop corrections to the double-emission cases. In particular, for the most complicated contributions, we provide details of master integrals calculation and IBP reduction in the presence of Heaviside functions.

80. N-jettiness soft function at NNLO in QCD

Ivan Pedron (KIT)

18/04/2024, 11:30

Motivated by the possibility of using advances in developing NNLO subtraction schemes to derive representations for building blocks of modern slicing methods, we derive a simple finite representation of the renormalized N-jettiness soft function at NNLO. The number of hard partons N appears as a parameter in the finite remainder. The cancellation of all infra-red and collinear singularities...

13. Subleading power corrections for event shape variables in e+e- collisions

Flavio Guadagni (University of Zurich)

18/04/2024, 12:00

The precise computation of cross section for scattering processes relevant at colliders involves the evaluation of phase-space integral that are IR divergent in d=4 dimensions. The subtraction of those divergences is a key ingredient to obtain fully-differential predictions for physical observables. One possibility is offered by non-local subtraction methods built upon suitably defined IR-safe...

104. Refactorisation and subtraction

Lorenzo Magnea (University of Torino)

18/04/2024, 12:30

In the context of infrared subtraction algorithms beyond NLO, it is necessary
to consider nested infrared limits of scattering amplitudes, in which several particles
become soft or collinear in a strongly-ordered sequence, as well as mixed real-virtual
contributions. I will discuss these configurations from the point of view of infrared factorisation,
and provide general definitions of...