arXiv subjects

M. Ovchynnikov

Publications and source records attributed to M. Ovchynnikov.

4 recordsLinked to original sources

arXiv2025

Feebly Interacting Particles: FIPs at LHCb

With the establishment and maturation of the experimental programs searching for new physics with sizeable couplings at the LHC, there is an increasing interest in the broader particle and astrophysics community for exploring the physics of light and feebly-interacting particles as a paradigm complementary to a New Physics sector at the TeV scale and beyond. FIPs@LHCb continues the successful series of the FIPs workshops, FIPs 2020 and FIPs 2022. The main focus of the workshop was to explore the LHCb potential to search for FIPs thanks to the new software trigger deployed during the recent upgrade. Equally important goals of the workshop were to update the available parameter space in the commonly used FIPs benchmarks by including recent results from the high energy physics community and to discuss recent theory progress necessary for a more accurate definition of observables related to FIP benchmarks. This document presents the summary of the talks presented at the workshops and the outcome of subsequent discussions.

hep-ph↗

arXiv2025

Summary Report of the Physics Beyond Colliders Study at CERN

The Physics Beyond Collider (PBC) Study Group was initially mandated by the CERN Management to prepare the previous European Particle Physics Strategy Update for CERN projects other than the high-energy frontier colliders. The main findings were summarized in an PBC Summary Report submitted to the Strategy Update. Following the Update process, the PBC Study Group was confirmed on a permanent basis with an updated mandate taking into account the strategy recommendations. The Study Group is now in charge of supporting the proponents of new ideas to address the technical issues and physics motivation of the projects ahead of their review by the CERN Scientific Committees and decision by the Management. The present document updates the previous PBC summary report to inform the new ongoing European Particle Physics Strategy Update process, taking into account the evolution of the CERN and worldwide landscapes and the new projects under consideration within the Study Group.

hep-ex↗

arXiv2025

PREFACE: A search for long-lived particles at the Large Hadron Collider

The Standard Model (SM) fails to explain many problems (neutrino masses, dark matter, and matter-antimatter asymmetry, among others) that may be resolved with new particles beyond the Standard model (BSM). The fact that such new particles are not yet observed may be explained either by their too high mass or by very small coupling to SM particles. The latter case implies long lifetimes. Such long-lived particles (LLPs) would have signatures different from those of SM particles. Searches in the "central region" are covered by the LHC general purpose experiments. The forward small angle region far from the interaction point (IP) is unexplored. Such particles would have large energy $E$ = $\mathcal{O}$(1~TeV) and Lorentz time dilation factor $\gamma = E/m \approx 10^2 - 10^{3}$, hence long decay distances. A new class of specialized LHC detectors dedicated to LLP searches has been proposed for the forward regions. Among these experiments, FASER is already operational, and FACET is under consideration at a location 100 meters from IP5 (the CMS intersection). However, some features of FACET require a specially enlarged beam pipe, which cannot be implemented for Run 4. In this study, we explore a simplified version of the proposed detector, PREFACE, compatible with the standard LHC beam pipe in the HL-LHC in Run 4. Realistic Geant4 simulations are performed and the background is evaluated. A preliminary analysis of the physics potential with the PREFACE geometry indicates that several significant channels could be accessible with sensitivities comparable to FACET and other LLP searches.

hep-ex↗

arXiv2022

Searches for Long-Lived Particles at the Future FCC-ee

The electron-positron stage of the Future Circular Collider, FCC-ee, is a frontier factory for Higgs, top, electroweak, and flavour physics. It is designed to operate in a 100 km circular tunnel built at CERN, and will serve as the first step towards $\geq$ 100 TeV proton-proton collisions. In addition to an essential and unique Higgs program, it offers powerful opportunities to discover direct or indirect evidence of physics beyond the Standard Model. Direct searches for long-lived particles at FCC-ee could be particularly fertile in the high-luminosity $Z$ run, where $5\times 10^{12}$ $Z$ bosons are anticipated to be produced for the configuration with two interaction points. The high statistics of Higgs bosons, $W$ bosons and top quarks in very clean experimental conditions could offer additional opportunities at other collision energies. Three physics cases producing long-lived signatures at FCC-ee are highlighted and studied in this paper: heavy neutral leptons (HNLs), axion-like particles (ALPs), and exotic decays of the Higgs boson. These searches motivate out-of-the-box optimization of experimental conditions and analysis techniques, that could lead to improvements in other physics searches.

hep-ex↗