Searcharxiv⌕ Search

arXiv subjects

S. Jadach

Publications and source records attributed to S. Jadach.

At least 19 recordsLinked to original sources
arXiv2026

Recent Developments in IR-Improved Amplitude-Based Resummation in Precision High Energy Collider Physics

We present recent developments in precision high energy collider physics based on the IR-improvement of unintegrable singularities in the infrared regime via amplitude-based resummation in $QED\times QCD \subset SU(2)_L \times U_1 \times SU(3)^c$. We focus on specific applications relevant to precision observables in LHC/FCC, LC, CLIC, CEPC, and CPPC physics, for which we present new results and some new issues.

hep-ph↗
arXiv2024

Amplitude-Based IR-Improvement in Precision LHC$/$FCC Physics

We present recent results based on the IR-improvement of unintegrable singularities in the infrared regime via amplitude-based resummation in $QED \times QCD \subset SU(2)_L \times U_1 \times SU(3)_c$. In the context of precision LHC$/$FCC physics, we focus on specific examples, such as the removal of QED contamination in PDFs evolved from data at ${Q_0}^2 \sim 2\; {\text{GeV}}^2$ and used in the evaluating precision observables in $pp \rightarrow Z + X \rightarrow \ell\bar{\ell} + X'$, in which we discuss new results and new issues.

hep-ph↗
arXiv2024

Outlook for the Theoretical Precision of the Luminosity at Future Lepton Colliders

The LEP precision physics requirements on the theoretical precision tag for the respective luminosity were $0.054 \%$ ($0.061\%$) at $M_Z$, where the former (latter) LEP result has (does not have) the pairs correction. For the contemplated FCC-ee, ILC, and CEPC Higgs/EW factories, one needs improvement at $M_Z$ to at least $0.01\%$ for the theoretical precision tag. We discuss the paths one may take to even exceed this latter goal and present an update on the current expectations for both $M_Z$ and proposed higher energy scenarios.

hep-ph↗
arXiv2024

Collinearly Enhanced YFS MC Approach to Precision High Energy Collider Physics

We improve the YFS IR resummation theory so that it includes all of the attendant collinear contributions which exponentiate. The attendant new resummed contributions are shown to agree with known results from the collinear factorization approach. We argue that they improve the corresponding precision tag for a given level of exactness in the respective YFS hard radiation residuals as the latter are realized in the YFS MC approach to precision high-energy collider physics.

hep-ph↗
arXiv2023

Collinearly Enhanced Realizations of the YFS MC Approach to Precision Resummation Theory

We extend the YFS IR resummation theory to include all of the attendant collinear contributions which exponentiate. This improves the original YFS formulation in which only a part of these contributions was exponentiated. We show that the new resummed contributions agree with known results from the collinear factorization approach and we argue that they improve the attendant precision tag for a given level of exactness in the respective YFS hard radiation residuals.

hep-ph↗
arXiv2023

New Results from IR-Improved Amplitude-Based Resummation in Quantum Field Theory

There is a continuing effort to support and prepare the precision physics programs for the present and planned future colliders such as HL-LHC, FCC, CLIC, CEPC, and CPPC. We discuss new results from IR-improved amplitude-based resummation in quantum field theory relevant to such support and preparation with some emphasis on the interplay between soft and collinear resummation algebras.

hep-ph↗
arXiv2022

KKMChh: matching CEEX photonic ISR to a QED-corrected parton shower

KKMChh adapts the CEEX (Coherent Exclusive Exponentiation) formalism of the Monte Carlo Program 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.

hep-ph↗
arXiv2022

Overview of theoretical precision of the luminosity at future electron-positron colliders

For both the FCC-ee and the ILC, to exploit properly the respective precision physics program, the theoretical precision tag on the respective luminosity will need to be improved from the analogs of the $ 0.054 \% (0.061\%)$ results at LEP at $M_Z$, where the former (latter) LEP result has (does not have) the pairs correction. At the FCC-ee at $M_Z$ one needs improvement to $0.01\%$, for example. We present an overview of the roads one may take to reach the required $0.01\%$ precision tag at the FCC-ee and of what the corresponding precision expectations would be for the FCC-ee$_{350}$, ILC$_{500}$, ILC$_{1000}$, and CLIC$_{3000}$ setups.

hep-ph↗
arXiv2022

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

We present the {\tt KKMCee 5.00.2} 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 re-written 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 \order{α^{1.5}} genuine weak corrections using a version of the classic {\tt DIZET} library and polarized $τ$ decays using {\tt TAUOLA} program. Both {\tt DIZET} and {\tt TAUOLA} external libraries are still in Fortran 77. In addition, a {\tt HEPMC3} interface to other MC programs, like parton showers and detector simulation, replaces the older {\tt HepEvt} interface. The {\tt HEPMC3} interface is also exploited in the implementation of the additional photon final state emissions in $τ$ decays using an external {\tt PHOTOS} library rewritten in C.

hep-ph↗
arXiv2022

Initial state QED radiation aspects for future $e^+e^-$ colliders

This white paper concerns theoretical and phenomenological aspects relevant to the physics of future $e^+e^-$ colliders, in particular regarding initial-state QED radiation. The contributions each contain key technical aspects, and are formulated in a pedagogical manner so as to render them accessible also to those who are not directly working on these and immediately-related topics. This should help both experts and non-experts understand the theoretical challenges that we shall face at future $e^+e^-$ colliders. Specifically, this paper contains descriptions of the treatment of initial state radiation from several Monte Carlo collaborations, as well as contributions that explain a number of more theoretical developments with promise of future phenomenological impact.

hep-ph↗
arXiv2022

Event Generators for High-Energy Physics Experiments

We provide an overview of the status of Monte-Carlo event generators for high-energy particle physics. Guided by the experimental needs and requirements, we highlight areas of active development, and opportunities for future improvements. Particular emphasis is given to physics models and algorithms that are employed across a variety of experiments. These common themes in event generator development lead to a more comprehensive understanding of physics at the highest energies and intensities, and allow models to be tested against a wealth of data that have been accumulated over the past decades. A cohesive approach to event generator development will allow these models to be further improved and systematic uncertainties to be reduced, directly contributing to future experimental success. Event generators are part of a much larger ecosystem of computational tools. They typically involve a number of unknown model parameters that must be tuned to experimental data, while maintaining the integrity of the underlying physics models. Making both these data, and the analyses with which they have been obtained accessible to future users is an essential aspect of open science and data preservation. It ensures the consistency of physics models across a variety of experiments.

hep-ph↗
arXiv2022

IR-Improved Amplitude-Based Resummation in Quantum Field Theory: New Results and New Issues

With the advancement of strategies for the precision physics programs for the HL-LHC, FCC-ee, FCC-hh, ILC, CLIC, CEPC, and CPPC, the need for proper control of the attendant theoretical precision tags is manifest. We discuss the role that amplitude-based resummation may play in this regard with examples from the LHC, the proposed new colliders and quantum gravity.

hep-ph↗
arXiv2022

Mini-Proceedings of the STRONG2020 Virtual Workshop on "Space-like and Time-like determination of the Hadronic Leading Order contribution to the Muon $g-2$"

The mini-proceedings of the STRONG2020 Virtual Workshop "Space-like and Time-like determination of the Hadronic Leading Order contribution to the Muon $g-2$", November 24--26 2021, are presented. This is the first workshop of the STRONG2020 WP21: JRA3-PrecisionSM: Precision Tests of the Standard Model (http://www.strong-2020.eu/joint-research-activity/jra3-precisionsm.html). The workshop was devoted to review of the working group activitity on: $(\it i)$ Radiative Corrections and Monte Carlo tools for low-energy hadronic cross sections in $e^+ e^-$ collisions; $(\it ii)$ Annotated database for $e^+e^-$ into hadrons processes at low energy; $(\it iii)$ Radiative Corrections and Monte Carlo tools for $μ$-$e$ elastic scattering.

hep-ph↗
arXiv2021

New Developments in KKMChh: Quark-Level Exponentiated Radiative Corrections and Semi-analytical Results

We describe a new semi-analytical program, KKhhFoam, which provides a simplified framework for testing the amplitude-level exponentiation scheme (CEEX) of the full KKMChh program in the semi-soft limit. The structure of the KKhhFoam integrand is also helpful for elucidating the structure of CEEX. We also discuss the representation of ISR in KKMChh and compare the ISR added by KKMChh to the effect of switching to a QED-corrected PDF, at the individual quark level, and suggest a new approach to running KKMChh with QED-corrected PDFs.

hep-ph↗
arXiv2021

IFI and ISR Effects for Z/$γ^*$ Drell-Yan Observables using ${\cal KK}$MC-hh

Continuing with our investigations of the expected sizes of multiple photon radiative effects in heavy gauge boson production with decay to charged lepton pairs in the context of the precision physics of the LHC, using \KK{MC}-hh 4.22 we consider IFI and ISR effects for specific Z/$γ^*$ Drell-Yan observables measured by the ATLAS and CMS Collaborations. With this version of \KK{MC}-hh, we have coherent exclusive exponentiation (CEEX) electroweak (EW) exact ${\cal O}(α^2 L)$ corrections in a hadronic MC and control over the corresponding EW initial-final interference (IFI) effects as well. Specifically, we illustrate the interplay between cuts of the type used in the measurement of $A_{FB}$ and $A_4$ at the LHC and the sizes of the expected responses of the attendant higher order corrections. We find that there are per cent to per mille level effects in the initial-state radiation, fractional per mille level effects in the IFI and per mille level effects in the over-all ${\cal O}(α^2 L)$ corrections that any treatment of EW corrections at the per mille level should consider. Our results are applicable to current LHC experimental data analyses.

hep-ph↗
arXiv2020

Overview of the Path to 0.01$\%$ Theoretical Luminosity Precision for the FCCee and Its Possible Synergistic Effects for Other FCC Precision Theory Requirements

To exploit properly the precision physics program at the FCC-ee, the theoretical precision tag on the respective luminosity will need to be improved from the 0.054$\%$ (0.061$\%$) results at LEP to 0.01$\%$, where the former (latter) LEP result has (does not have) the pairs correction. We present an overview of the roads one may take to reach the required 0.01$\%$ precision tag at the FCC-ee and we discuss possible synergistic effects of the walk along these roads for other FCC precision theory requirements.

hep-ph↗
arXiv2020

The Monte Carlo Program KKMC for the Lepton or Quark Pair Production at LEP/SLC Energies -- updates of electroweak calculations

Since the {\tt KKMC} program was published for the first time over 20 years ago, it has gained popularity and was exploited in a broad spectrum of applications. The core part of the program itself did not change much. In contrast, some of the libraries have evolved substantially. The aim of this publication is to archive four versions, alternative to the one published 20 years ago versions of the electroweak libraries (or just parameter initialization versions), which were instrumental for the precision Standard Model calculation from the end of LEP era till now and for the sake of the future applications/comparisons for the future electron-positron colliders, in particular for the FCC-ee related studies. These electroweak libraries are useful for the hadron collider applications as well, for instance for {\tt KKMC-hh} or {\tt TauSpinner} projects.

hep-ph↗