Monte Carlo Event Generator updates, for tau pair events at Belle II energies

KKMChh adapts the CEEX (Coherent Exclusive Exponentiation) formalism of the Monte CarloProgram KKMC for Z boson production and decay to hadron scattering. Amplitude-level soft photon exponentiation of initial and final state radiation, together with initial-final interference, is matched to a perturbative calculation to second order next-to-leading logarithm, and electroweak corrections to the hard process are included via DIZET. The first release of KKMChh included complete initial state radiation calculated with current quark masses. This version assumes idealized pure-QCD PDFs with negligible QED contamination. Traditional PDFs neglect QED evolution but are not necessarily free of QED influence in the data. QED-corrected PDFs provide a firmer starting point for precision QED work. We describe a new procedure for matching KKMChh's initial state radiation to a QED-corrected PDF, and compare this to earlier approaches.

show abstract

“…[14] We also envisage updating the photos and tauola libraries used by KKMChh and KKMCee; see Ref. [15] and references therein.…”

Section: Pdf Matching Via Negative Initial State Radiationmentioning

confidence: 99%

KKMChh: Matching CEEX Photonic ISR to a QED-Corrected Parton Shower

Yost¹,

Jadach²,

Ward³

et al. 2022

Proceedings of 41st International Conference on High Energy Physics — PoS(ICHEP2022)

View full text Add to dashboard Cite

show abstract

“…In fact, PHOTOS is already rewritten to C [20] and is interfaced to the present KKMCee. For TAUOLA the first preparatory step in this direction is documented in [21] (see also [22]) and the on-going effort on the TAUOLA improvements is expected to rely on fits to Belle II data.…”

Section: Introductionmentioning

confidence: 99%

Multi-photon Monte Carlo event generator KKMCee for lepton and quark pair production in lepton colliders

Jadach¹,

Ward²,

Was³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

We present the KKMCee 5.0 Monte Carlo event generator for lepton and quark pair production for the high energy electron-positron annihilation process. It is still the most sophisticated event generator for such processes. Its entire source code is rewritten in the modern C++ language. It reproduces all features of the older KKMC code in Fortran 77. However, a number of improvements in the Monte Carlo algorithm are also implemented. Most importantly, it is intended to be a starting point for the future improvements, which will be mandatory for the future high precision lepton collider projects. As in the older version, in addition to higher order QED corrections, it includes so-called O(α 1.5 ) genuine weak corrections using a version of the classic DIZET library and polarized τ decays using TAUOLA program. Both DIZET and TAUOLA external libraries are still in Fortran 77. In addition, a HEPMC3 interface to other MC programs, like parton showers and detector simulation, replaces the older HepEvt interface. The HEPMC3 interface is also exploited in the implementation of the additional photon final state emissions in τ decays using an external PHOTOS library rewritten in C.

show abstract

“…Technical changes are not addressed, they can be found in Ref. [8]. Recent extensions of phase space generators, enable not only full implementation of bremsstrahlung-like processes where virtual photon decay into pair of leptons, but also the possibilities of emitting dark photon or dark scalars, now introduced into tauola and photospp, and instrumental for the present talk.…”

Section: Introductionmentioning

confidence: 99%

The tau lepton Monte Carlo Event Generation -- imprinting New Physics models with exotic scalar or vector states into simulation samples

Banerjee¹,

Biswas²,

Przedzinski³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

The Monte Carlo for lepton pair production and τ decays consist of KKMC for lepton pair production, tauola for τ lepton decays and photos for radiative corrections in decays.An effort for adaptation of the system for precision data being collected at the Belle II experiment included simulation of additional light lepton pairs. Extension to processes where lepton pair is produced through narrow resonances, like dark photon or dark scalar (φ) resonances, was straight forward.Modified programs versions are available in stand-alone format from gitlab repository or through the basf2 system of Belle II software. It was explained recently during the International Workshop on Tau Lepton Physics September, 2021, Bloomington IN. Now we concentrate on simulations for φ resonance, a hypothetical object which could be responsible for anomalous moment g − 2 in Z − τ − τ interactions through virtual contributions.

show abstract

Monte Carlo Event Generator updates, for tau pair events at Belle II energies

Cited by 3 publications

References 26 publications

KKMChh: Matching CEEX Photonic ISR to a QED-Corrected Parton Shower

KKMChh: Matching CEEX Photonic ISR to a QED-Corrected Parton Shower

Multi-photon Monte Carlo event generator KKMCee for lepton and quark pair production in lepton colliders

The tau lepton Monte Carlo Event Generation -- imprinting New Physics models with exotic scalar or vector states into simulation samples

Contact Info

Product

Resources

About