PHOTOS Interface in C++; Technical and Physics Documentation

Abstract

For five years now, PHOTOS Monte Carlo for bremsstrahlung in the decay of particles and resonances has been available with an interface to the C++ HepMC event record. The main purpose of the present paper is to document the technical aspects of the PHOTOS Monte Carlo installation and present version use. A multitude of test results and examples are distributed together with the program code. The PHOTOS C++ physics precision is better than its FORTRAN predecessor and more convenient steering options are also available. An algorithm for the event record interface necessary for process dependent photon emission kernel is implemented. It is used in Z and W decays for kernels of complete first order matrix elements of the decays. Additional emission of final state lepton pairs is also available. Physics assumptions used in the program and properties of the solution are reviewed. In particular, it is explained how the second order matrix elements were used in design and validation of the program iteration procedure. Also, it is explained that the phase space parametrization used in the program is exact.

Updated version; for the program as of April 2015

Cited by in corpus (16)

• An Introduction to PYTHIA 8.2
• On the Standard Model predictions for $R_K$ and $R_{K^{\ast }}$
• Study of the doubly charmed tetraquark $T_{cc}^{+}$
• Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector
• Cross-section measurements of the Higgs boson decaying into a pair of tau-leptons in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Fiducial and differential cross sections of Higgs boson production measured in the four-lepton decay channel in $pp$ collisions at $\sqrt{s}$=8 TeV with the ATLAS detector
• Precision Studies of Observables in pp->W->l nu and pp->gamma,Z->l+l- processes at the LHC
• In situ calibration of large-$R$ jet energy and mass in 13 TeV proton-proton collisions with the ATLAS detector
• Search for new light gauge bosons in Higgs boson decays to four-lepton final states in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector at the LHC
• The weak radiative pion vertex in τ^- ->π^-ν_τl^+ l^- decays
• Bremsstrahlung simulation in K to pi l^pm nu_l (gamma) decays
• The tau leptons theory and experimental data: Monte Carlo, fits, software and systematic errors
• SANC system and its applications for LHC
• $\frac{|V_{ub}|}{|V_{cb}|}$ and Quest for New Physics
• Tau lepton production and decays: perspective of multi-dimensional distributions and Monte Carlo methods
• Monte Carlo Event Generator updates, for tau pair events at Belle II energies