# Glossary

## Acronyms

- BR
a branching ratio

- EW
electroweak

- FKS
the Frixione-Kunszt-Signer scheme used in McMule. See Section The FKS^2 scheme.

- FSR
final state radiation

- IR
infra-red

- HVP
hadronic vacuum polarisation

- ISR
initial state radiation

- LO
leading order

- LP
leading power

- NLO
next-to-leading order

- NLP
next-to-leading power

- NNLO
next-to-next-to-leading order

- NTS
next-to-soft

- OS
on-shell renormalisation scheme in which the masses correspond to the poles of the propagators and \(\alpha=\alpha(q^2=0)\) in the Thomson limit

- PCS
pseudo-collinear sinuglarities, the numerical instabilties in

\[\mathcal{M}_{n+1}^{(\ell )} \propto \frac{1}{q\cdot k} = \frac1{\xi^2}\frac1{1-y\beta}\]where \(y\) is the angle between photon (\(k\)) and electron (\(q\)). For large velocities \(\beta\) (or equivalently small masses), this becomes almost singular as \(y\to1\).

- PID
particle identification, the ordering of particles in the code

- RNG
random number generator, used to generate pseudo-random numbers for the Monte Carlo generation. See Section Random number generation

- SHA1
secure-hasing-algorithm-1, used for hashing McMule’s source code in autoversioning

- SM
the Standard Model of particle physics

- VP
vacuum polarisation

## Technical terms

- config file
a shell file specifying, among other things, the statistics to be used

- containerisation
the concept of bundling all dependecies etc. with McMule. See Sections Basics of containerisation and Basics of containerisation

- container
a container that has bundled all dependecies etc. with McMule. See Sections Basics of containerisation and Basics of containerisation

- corner region
a region of phase space where the mapping defined in Section Phase-space generation is not unique. The corner region refers to the smaller part of this double mapping.

- counter-event
the soft event that gets subtracted in FKS, cf. (6)

- event
the hard event that does not get subtracted in FKS, cf. (6)

- full period
a surjective RNG

- generic pieces
a generic piece describes a part of the calculation such as the real or virtual corrections that themselves may be further subdivided as is convenient.

- generic processes
A generic process is a prototype for the physical process such as \(\ell p\to\ell p\) where the flavour of the lepton \(\ell\) is left open.

A menu file contains a list of jobs to be computed s.t. the user will only have to vary the random seed and \(\xi_{c}\) by hand as the statistical requirements are defined globally in a config file.

- measurement function
A function that takes as arguments the four-momenta of all particles involved in the reaction and returns the experimentally measured quantity.

- process group
Processes are grouped into process grous if they share matrix elements such as \(\mu\to\nu\bar\nu e\) and \(\mu\to\nu\bar\nu e\gamma\) (

`mudec`

) or \(e\mu\to e\mu\) and \(\ell p\to\ell p\) (`mue`

).- random seed
the initial value of the RNG. In McMule this may be between 1 and 2<sup>31</sup>-2. See Section Random number generation for further details.

- soft cut
a value of \(\xi\) below which no subtraction takes place and the integrand is set to zero

- submission script
a script that is provided by pymule to run a menu file.