arXiv subjects

Jakob Beyer

Publications and source records attributed to Jakob Beyer.

8 recordsLinked to original sources

arXiv2023

The International Linear Collider: Report to Snowmass 2021

The International Linear Collider (ILC) is on the table now as a new global energy-frontier accelerator laboratory taking data in the 2030s. The ILC addresses key questions for our current understanding of particle physics. It is based on a proven accelerator technology. Its experiments will challenge the Standard Model of particle physics and will provide a new window to look beyond it. This document brings the story of the ILC up to date, emphasizing its strong physics motivation, its readiness for construction, and the opportunity it presents to the US and the global particle physics community.

physics.acc-ph↗

arXiv2022

Report of the Topical Group on Electroweak Precision Physics and Constraining New Physics for Snowmass 2021

The precise measurement of physics observables and the test of their consistency within the standard model (SM) are an invaluable approach, complemented by direct searches for new particles, to determine the existence of physics beyond the standard model (BSM). Studies of massive electroweak gauge bosons (W and Z bosons) are a promising target for indirect BSM searches, since the interactions of photons and gluons are strongly constrained by the unbroken gauge symmetries. They can be divided into two categories: (a) Fermion scattering processes mediated by s- or t-channel W/Z bosons, also known as electroweak precision measurements; and (b) multi-boson processes, which include production of two or more vector bosons in fermion-antifermion annihilation, as well as vector boson scattering (VBS) processes. The latter categories can test modifications of gauge-boson self-interactions, and the sensitivity is typically improved with increased collision energy. This report evaluates the achievable precision of a range of future experiments, which depend on the statistics of the collected data sample, the experimental and theoretical systematic uncertainties, and their correlations. In addition it presents a combined interpretation of these results, together with similar studies in the Higgs and top sector, in the Standard Model effective field theory (SMEFT) framework. This framework provides a model-independent prescription to put generic constraints on new physics and to study and combine large sets of experimental observables, assuming that the new physics scales are significantly higher than the EW scale.

hep-ph↗

arXiv2022

Interplay of Beam Polarisation and Systematic Uncertainties in Electroweak Precision Measurements at Future $e^+ e^-$ Colliders

Future high-energy $\textrm{e}^+\textrm{e}^-$ colliders will provide some of the most precise tests of the Standard Model. Statistical uncertainties on electroweak precision observables and triple gauge couplings are expected to improve by orders of magnitude over current measurements. This provides a new challenge in accurately assessing and minimizing the impact of experimental systematic uncertainties. Beam polarization may hold a unique potential to isolate and determine the size of systematic effects. So far, studies have mainly focused on the statistical improvements from beam polarisation. This study aims to assess, for the first time, its impact on systematic uncertainties. A combined fit of precision observables, such as chiral fermion couplings and anomalous triple gauge couplings, together with experimental systematic effects is performed on generator-level differential distribution of 2-fermion and 4-fermion final-states. Different configurations of available beam polarisations and luminosities are tested with and without systematic effects, and will be discussed in the context of the existing projections on fermion and gauge boson couplings from detailed experimental simulations.

hep-ph↗

arXiv2021

Interplay of beam polarisation and systematic uncertainties at future $e^+e^-$ colliders

Future high-energy $e^+e^-$ colliders will provide some of the most precise tests of the Standard Model. Statistical uncertainties on electroweak precision observables and triple gauge couplings are expected to improve by orders of magnitude over current measurements. This provides a new challenge in accurately assessing and minimising the impact of systematic uncertainties. Beam polarisation may hold a unique potential to isolate and determine the size of systematic effects. So far, studies have mainly focused on the statistical improvements from beam polarisation. This study aims to assess, for the first time, its impact on systematic uncertainties. A combined fit of precision observables, such as chiral fermion couplings and anomalous triple gauge couplings, together with experimental systematic effects is performed on generator-level differential distribution of 2-fermion and 4-fermion final-states. Different configurations of available beam polarisations and luminosities are tested with and without systematic effects, and will be discussed in the context of the existing projections on fermion and gauge boson couplings from detailed experimental simulations.

hep-ex↗

arXiv2021

Isolating systematic effects with beam polarisation at $e^+e^-$ colliders

Future high-energy $e^+e^-$ colliders will provide some of the most precise tests of the Standard Model. Statistical uncertainties are expected to improve by orders of magnitude over current measurements. This provides a new challenge in accurately assessing and minimizing systematic uncertainties. Beam polarisation may hold a unique potential to isolate and determine the size of systematic effects. This study aims to set this hypothesis by setting up a combined fit of systematic effect and electroweak observables that can test different configurations of available beam polarisations and luminosities. A framework for this fit is developed. In a first test it fits the luminosity and polarisation with external constraints to 2-fermion and 4-fermion differential distributions. An implementation of a first systematic - the muon acceptance - shows consistent behaviour in this framework. This lays the groundwork for testing the interplay of systematic and physical effects in the presence or absence of beam polarisation.

hep-ex↗

arXiv2020

ILD benchmark: Quartic Gauge Couplings

The quartic gauge coupling (QGC) of the electroweak interaction can be used as a probe for physics beyond the Standard Model and has been previously measured at the Large Hadron Collider. However, to achieve sensitivity to small deviations the couplings must be measured with precision beyond the capability of a hadron collider. An electron-positron collider with center-of-mass energies in the TeV range can precisely probe the QGC and test a variety of models. The International Linear Collider is such a collider project with a possible extension to $1\,$TeV. In this note the critical reconstruction aspects of a QGC analysis in the vector boson scattering (VBS) channel of $e^+e^- \rightarrow ν\barν q\bar{q} q\bar{q}$ at $\sqrt{s}=1\,$TeV are identified for the International Large Detector. Generator level information from the event generator and simulation is used to gain access to influence of separate reconstruction effects. The separation of hadronic $WW$ and $ZZ$ decays by their invariant mass is chosen to quantify the strength of the effects. In the current simple reconstruction scheme the main obstacles are observed to be the removal of beam backgrounds, the jet clustering, and semi-leptonic decays within jets. At high center-of-mass energies of the VBS interaction jet clustering is found to no longer be a limiting factor. Points of optimizations are laid out for these aspects. In the case of semi-leptonic decays, proof-of-principal tests for corrections are performed and found to be challenging. A full analysis which includes the extraction of limits on anomalous QGCs remains open. Sensitivities similar to those achieved in generator level studies with approximated detector effects are expected.

hep-ex↗

arXiv2020

Precision measurements of Triple Gauge Couplings at future electron-positron colliders

A precise knowledge of charged Triple Gauge Couplings (cTGCs) is important for the determination of Higgs couplings and for constraining physics beyond the Standard Model. Future high-energy $e^{+}e^{-}$ colliders could have a significantly improved sensitivity to anomalous cTGCs. The fit framework presented here extracts cTGCs in parallel with chiral cross sections and beam polarisation parameters. It demonstrates that cTGCs can be measured with precision in the $10^{-3}-10^{-4}$ range. A strong dependence of the cTGC sensitivity on the available luminosities and polarisations is observed.

hep-ex↗

arXiv2019

VBSCan Thessaloniki 2018 Workshop Summary

This document reports the first year of activity of the VBSCan COST Action network, as summarised by the talks and discussions happened during the VBSCan Thessaloniki 2018 workshop. The VBSCan COST action is aiming at a consistent and coordinated study of vector-boson scattering from the phenomenological and experimental point of view, for the best exploitation of the data that will be delivered by existing and future particle colliders.

hep-ph↗