arXiv subjects

David Rousso

Publications and source records attributed to David Rousso.

4 recordsLinked to original sources

arXiv2026

Searches for massive, long-lived particles in events with displaced vertices with ATLAS

Many recent efforts at the LHC have been made to search for new particles that do not decay promptly but are instead long-lived. This has been done via many different exotic signatures, including searches performed at ATLAS for displaced vertices (DV), where the new long-lived particle decays into multiple visible tracks after having traveled a certain distance into the detector. This talk covers two such searches: a Run 2 search for DVs in events triggered by missing transverse energy, and a Run 3 search for DVs in events triggered by muons. The former search is the first to use a new "fuzzy" displaced vertex reconstruction algorithm, alongside the standard one, to effectively reconstruct cases where the long-lived particle decays into heavy quarks that are themselves slightly long-lived, hence causing the final visible decay products to not point back exactly to the same vertex, setting limits on Higgs Portal, SUSY, and DFSZ axino models. The latter search is the first to use a new displaced muon trigger, setting limits on RPV SUSY models.

hep-ex↗

arXiv2026

Optomechanical platform for high-frequency gravitational wave and vector dark matter detection

We present a proposal for a nanomechanical membrane resonator integrated into a moderate-finesse ($\mathcal{F}\sim 10$) optical cavity as a versatile platform for detecting high-frequency gravitational waves and vector dark matter. Gravitational-wave sensitivity arises from cavity-length modulation, which resonantly drives membrane motion via the radiation-pressure force. This force also enables in situ tuning of the membrane's resonance frequency by nearly a factor of two, allowing a frequency coverage from 0.5 to 40 kHz using six membranes. The detector achieves a peak strain sensitivity of $2\times 10^{-23}/\sqrt{\text{Hz}}$ at 40 kHz. Using a silicon membrane positioned near a gallium-arsenide input mirror additionally provides sensitivity to vector dark matter via differential acceleration from their differing atomic-to-mass number ratios. The projected reach surpasses the existing limits in the range of $2\times 10^{-12}$ to $2\times 10^{-10}$ $\text{eV}/c^2$ for a one-year measurement. Consequently, the proposed detector offers a unified approach to searching for physics beyond the Standard Model, probing both high-frequency gravitational waves and vector dark matter.

astro-ph.IM↗

arXiv2025

Quirk SUEP

We propose searching for physics beyond the Standard Model in the low-transverse-momentum tracks accompanying hard-scatter events at the LHC. TeV-scale resonances connected to a dark QCD sector could be enhanced by selecting events with anomalies in the track distributions. As a benchmark, a quirk model with microscopic string lengths is developed, including a setup for event simulation. For this model, strategies are presented to enhance the sensitivity compared to inclusive resonance searches: a simple cut-based selection, a supervised search, and a model-agnostic weakly supervised anomaly search with the CATHODE method. Expected discovery potentials and exclusion limits are shown for 140 fb$^{-1}$ of 13 TeV proton-proton collisions at the LHC.

hep-ph↗

arXiv2016

High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays

A limiting factor in the development of mid-infrared optics is the lack of abundant materials that are transparent, low cost, lightweight, and easy to machine. In this paper, we demonstrate a metasurface device that circumvents these limitations. A flat lens based on antenna reflectarrays was designed to achieve near diffraction-limited focusing with a high efficiency (experiment: 80%, simulation: 83%) at 45(o) incidence angle at {\lambda} = 4.6 {\mu}m. This geometry considerably simplifies the experimental arrangement compared to the common geometry of normal incidence which requires beam splitters. Simulations show that the effect of comatic aberrations is small compared to parabolic mirrors. The use of single-step photolithography allows large scale fabrication.

physics.optics↗