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Sofie Nordahl Erner

Publications and source records attributed to Sofie Nordahl Erner.

3 recordsLinked to original sources

SET-ANUBIS: a modular pipeline for ANUBIS long-lived particle sensitivity studies

The proposed ANUBIS detector has been designed to search for Long-Lived Particle (LLP) signatures, which have become a focus for a variety of experiments within recent years. Due to the variety of possible LLP models and the need for directly comparable sensitivity results highlighting the potential coverage of ANUBIS, the SET-ANUBIS (Simulation, accEptance and sensiTivity studies framework for ANUBIS) framework has been developed. SET-ANUBIS is a flexible open-source Python framework that can perform full sensitivity studies of LLP signatures for the ANUBIS detector, allowing others to directly produce ANUBIS-like limits or even implement other geometries and detectors. It starts from a Universal FeynRules Output model or user-supplied rates; it exposes model parameters and particle content for user modification, and evaluates decay widths, branching ratios and lifetimes. MARTY can also be used to compute matrix elements, decay widths, branching ratios, and cross-sections. Then the framework prepares or runs event generation through Pythia8 or MadGraph, ingests HepMC event records, models the geometry of the ATLAS cavern and ANUBIS tracking stations, and applies a configurable sequence of geometric, kinematic and isolation requirements to select a set of surviving LLP candidates for evaluation. The implementation follows a ports-and-adapters architecture so that the core logic remains separate from external generators, persistent storage and visualisation. A scan-aware SQLite catalogue and content-addressed store preserve cards, metadata and compact selection-ready event bundles while avoiding duplicate artifacts. A pre-release version of the SET-ANUBIS framework has already been used to successfully derive the sensitivity of ANUBIS to three LLP benchmark models involving a Higgs portal and a Heavy Neutral Lepton model.

hep-ph↗

Projected sensitivity of the ANUBIS detector to heavy neutral leptons

Long-Lived Particles (LLPs) are a common feature in various extensions to the Standard Model (SM) that seek to address known limitations. The ANUBIS detector has been proposed to extend the sensitivity of the ATLAS experiment at the LHC to LLPs by instrumenting the ceiling of the ATLAS detector cavern. This article presents the projected sensitivity of ANUBIS to Heavy Neutral Leptons (HNLs). For a minimal Majorana HNL model that only couples to a single flavour of lepton ($e$ or $μ$) ANUBIS reaches a maximum sensitivity of $|V_{1e}|^2=1.8\times10^{-8}$ and $|V_{1μ}|^2=1.9\times10^{-8}$ for a HNL mass of $m_{N_1}=6.4$ GeV and 6.3 GeV respectively. This provides complementary coverage to other proposed LLP experiments in the HNL parameter-space, with potential for significant improvement during ANUBIS data-taking through advances in analysis strategies. The results are obtained with SET-ANUBIS, a flexible framework to evaluate the sensitivity of ANUBIS to a variety of LLP models.

hep-ex↗

How to measure the spin of invisible states in $e^+e^- \to γ+ X$

We examine the production of an invisible state $X$ together with a photon, $e^+e^- \to γ+X$, at electron positron colliders and present measurement strategies that can detect the spin of the invisible state as well as the underlying production mechanism, based on the angular distribution of the final state photon, the cross sections for polarized initial states and the photon polarization. Our measurement strategy can be used to identify whether the invisible state is a hidden photon or an axion. The results are compared with a detailed analysis of the Standard Model background and we calculate the sensitivity reach for searches for axions and hidden photons at Belle II.

hep-ph↗