Future Collider Projects Research Articles

CLUE: a clustering algorithm for current and future experiments

CLUE (CLUstering of Energy) is a fast parallel clustering algorithm for High Granularity Calorimeters in High Energy Physics. In these types of detectors, the standard clustering algorithms using combinatorics are expected to fail due to large number of digitized energy deposits (hits) in the reconstruction stage bringing to a consequent memory/timing explosion. This innovative algorithm uses a grid spatial index for fast querying of neighbors and its timing scales linearly with the number of hits within the range considered. Initially CLUE was developed in a standalone repository that allows performance benchmarking with respect to its CPU and GPU implementations, demonstrating the power of algorithmic parallelization in the coming era of heterogeneous computing. CLUE has been successfully used in simulation and beam tests of the High Granularity Calorimeter to be installed for the upgrade of the CMS detector in Phase-2 of the HL-LHC. Recently CLUE was also imported in the key4hep framework and first results will be shown for detectors proposed in future collider projects.

Higgs Boson studies at future particle colliders

This document aims to provide an assessment of the potential of future colliding beam facilities to perform Higgs boson studies. The analysis builds on the submissions made by the proponents of future colliders to the European Strategy Update process, and takes as its point of departure the results expected at the completion of the HL-LHC program. This report presents quantitative results on many aspects of Higgs physics for future collider projects of sufficient maturity using uniform methodologies.

A Higgs boson below 125 GeV?!

We briefly summarize some searches for Higgs bosons with a mass of [Formula: see text] GeV at LEP and the LHC. We discuss a possible signal in the diphoton decay mode at [Formula: see text] GeV as reported by CMS, together with a [Formula: see text] hint in the [Formula: see text] final state at LEP. We briefly review possible interpretation of such a new particle in various BSM models. We focus on possible explanations as reported within the NMSSM and the [Formula: see text]SSM. Conclusions for future collider projects are briefly outlined.

New physics in multi-Higgs boson final states

We explore the potential for the discovery of the triple-Higgs signal in the decay channel at a 100 TeV hadron collider. We consider both the Standard Model and generic new-physics contributions, described by an effective Lagrangian that includes higher-dimensional operators. The selected subset of operators is motivated by composite-Higgs and Higgs-inflation models. In the Standard Model, we perform both a parton-level and a detector-level analysis. Although the parton-level results are encouraging, the detector-level results demonstrate that this mode is really challenging. However, sizable contributions from new effective operators can largely increase the cross section and/or modify the kinematics of the Higgs bosons in the final state. Taking into account the projected constraints from single and double Higgs-boson production, we propose benchmark points in the new physics models for the measurement of the triple-Higgs boson final state for future collider projects.

From LHC to SLHC, ILC and Beyond

A review and possible road map for future collider projects at the high energy frontier are presented. Opportunities for photon physics will be pointed out.

Ground vibration measurements for Fermilab future collider projects

This article presents results of wideband seismic measurements at the Fermilab site, namely, in the tunnel of the Tevatron and on the surface nearby, as well as in two deep tunnels in the Illinois dolomite, thought to be a possible geological environment of the Fermilab future accelerators.