Glossary

Acronyms

BR

a branching ratio

DSL

a domain specific language

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

TOML

the name of the markup language used for config files. See https://toml.io/ for more information

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)

distance function

A function which determines the distance between two points in the momentum phasespace.

event

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

executor

a pymule plugin that executes a menu file

fatal

A test which is not allowed to fail, such as the Soft photon limit or Swap symmetry tests.

full period

a surjective RNG

generic piece

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 process

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.

image

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

menu file

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.

non-fatal

A test which is allowed to fail, but ideally shouldn’t. Includes most lorentz transformations.

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 \(2^{31}-2\). See Section Random number generation for further details.

shared library

a library that can be loaded dynamically. On Linux system the customary filename suffix is .so. McMule can be used as a shared library and also load a shared library for the user file.

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.

userfile

the *.f95 or *.c file which defines the QUANT function or measurement function along with histogram variables.

which_piece

A which piece is a single subdivision of a generic piece designed to build up to a full calculation