arXiv subjects

John Carlton

Publications and source records attributed to John Carlton.

8 recordsLinked to original sources

arXiv2026

Technical Proposal for the Atom Interferometer CERN Experiment (AICE) Facility

We present the technical proposal for the Atom Interferometer CERN Experiment (AICE), a $\mathcal{O}(100)$ m vertical atom interferometer to be installed against the wall of the PX46 access shaft to the LHC. AICE is conceived as a versatile and flexible long-baseline atom-interferometry facility whose primary scientific goal is probing for bosonic ultralight dark matter (ULDM) in a mass range inaccessible to other experiments, with a secondary goal of pioneering the exploration of gravitational waves (GWs) with frequencies in the range ${\sim}$0.03-3 Hz as a pathfinder for future longer-baseline detectors. The initial configuration employs ultracold $^{87}$Sr atoms in a single-photon 698-nm interferometer with three shaft-based atom sources in a multi-source gradiometer geometry, supported by one surface reference source for laser stabilisation and diagnostics, to target scalar ULDM. Operation with $^{88}$Sr will give sensitivity to axion-like particles (ALPs), vector ULDM with $B-L$ couplings and violation of the principle of equivalence, while a $^{171}$Yb upgrade will improve the sensitivity to $B-L$ couplings and equivalence violations. Probing the Einstein equivalence principle (EP) and measuring $\alpha$ will proceed in parallel with the ULDM searches. A conceptual feasibility study and a detailed technical implementation study have established that PX46 is a uniquely mature and implementation-ready site, with no technical showstoppers. Completing site preparation works during LS3 would enable the subsequent installation and operation of AICE without impacting HL-LHC operations. The detector design builds on the VLBAI and MAGIS experiments and the AION-10 Technical Design Report, scaling the strontium gradiometer architecture to the $\sim$100 m baseline. AICE is endorsed by the TVLBAI Proto-Collaboration, comprising 57 institutions in 22 countries.

hep-ex↗

arXiv2026

New Energy-Loss Constraints on Dark Sectors from Deeply Inelastic Scattering with Initial State Radiation

We employ the joint QED and QCD factorization of deeply inelastic, electron-proton scattering with generic initial state radiation to probe the possibility of exotic particle emission -- i.e., of weakly coupled particles originating from a dark or hidden sector -- through anomalous energy loss. We leverage this possibility through the consideration of phase-space-limited kinematic regions, for which the emission of an additional, undetected particle can particularly impact the associated cross-section. In this first paper, as a proof of principle, we focus on radiation from the incoming electron, considering the modification of the lepton distribution function from the emission of particles, that could have spin of up to 2 and various, well-motivated electron couplings. We illustrate the sensitivity of our approach through the computation of the modified cross-sections for the emission of MeV-GeV mass-scale, spin 0 particles in kinematics chosen for their sensitivity to initial state electron radiation and suitable to the forward-backward detection sensitivity of the ePIC detector at the EIC.

hep-ph↗

arXiv2025

Searching for screened scalar forces with long-baseline atom interferometers

Screened scalars are ubiquitous in many dark-sector models. They give rise to non-trivial fifth forces whilst evading experimental constraints through density-dependent screening mechanisms. We propose equipping a 10\,m-scale long-baseline atom interferometer with an annular planar source mass inside the vacuum chamber to search for such screened fifth forces. Two key challenges arise: distinguishing the static fifth force from backgrounds, and isolating it from the plate's Newtonian gravity. We introduce the `$Q$-flip protocol', which alternates between interferometry sequences to induce controllable time-dependence, aiding signal extraction and de-trending of transient noise. We further develop an \emph{in situ} calibration procedure to characterise the plate's Newtonian gravity and reach shot-noise-limited sensitivity. We show that our proposal could test theoretically motivated parameter space, advancing existing bounds in chameleon and symmetron screened scalar models by $1$ to $1.5$ orders of magnitude. Our proposal is directly applicable to forthcoming experiments, such as AION-10 or VLBAI, and is readily extensible to broader theoretical models and longer baselines.

hep-ph↗

arXiv2024

Terrestrial Very-Long-Baseline Atom Interferometry: Summary of the Second Workshop

This summary of the second Terrestrial Very-Long-Baseline Atom Interferometry (TVLBAI) Workshop provides a comprehensive overview of our meeting held in London in April 2024, building on the initial discussions during the inaugural workshop held at CERN in March 2023. Like the summary of the first workshop, this document records a critical milestone for the international atom interferometry community. It documents our concerted efforts to evaluate progress, address emerging challenges, and refine strategic directions for future large-scale atom interferometry projects. Our commitment to collaboration is manifested by the integration of diverse expertise and the coordination of international resources, all aimed at advancing the frontiers of atom interferometry physics and technology, as set out in a Memorandum of Understanding signed by over 50 institutions.

hep-ex↗

arXiv2024

Massive graviton dark matter searches with long-baseline atom interferometers

Atom interferometers offer exceptional sensitivity to ultra-light dark matter (ULDM) by precisely measuring effects on atomic systems. Previous studies have demonstrated their capability to detect scalar and vector ULDM candidates, yet their potential for probing spin-2 ULDM remains unexplored. In this work, we address this gap by investigating the sensitivity of atom interferometers to spin-2 ULDM across several frameworks for massive gravity, including the Lorentz-invariant Fierz-Pauli case and two distinct Lorentz-violating scenarios. We show that coherent oscillations of the spin-2 ULDM field induce measurable phase shifts in atom interferometers through three coupling mechanisms: scalar interactions that modify atomic energy levels, and vector and tensor effects that alter the propagation of both atoms and light. We demonstrate that these multifaceted interactions enable atom interferometers to probe a range of ULDM properties and mass scales that are inaccessible to laser interferometric gravitational wave detectors. Our results establish the potential of atom interferometers to open a new experimental frontier for spin-2 dark matter detection.

hep-ph↗

arXiv2024

Clear skies ahead: characterizing atmospheric gravity gradient noise for vertical atom interferometers

Terrestrial long-baseline atom interferometer experiments are emerging as powerful tools for probing new fundamental physics, including searches for dark matter and gravitational waves. In the frequency range relevant to these signals, gravity gradient noise (GGN) poses a significant challenge. While previous studies for vertical instruments have focused on GGN induced by seismic waves, atmospheric fluctuations in pressure and temperature also lead to variations in local gravity. In this work, we advance the understanding of atmospheric GGN in vertical atom interferometers, formulating a robust characterization of its impact. We evaluate the effectiveness of underground placement of atom interferometers as a passive noise mitigation strategy. Additionally, we empirically derive global high- and low-noise models for atmospheric pressure GGN and estimate an analogous range for atmospheric temperature GGN. To highlight the variability of temperature-induced noise, we compare data from three prospective experimental sites. Our findings establish atmospheric GGN as comparable to seismic noise in its impact and underscore the importance of including these effects in site selection and active noise monitoring for future experiments.

gr-qc↗

arXiv2023

Terrestrial Very-Long-Baseline Atom Interferometry: Workshop Summary

This document presents a summary of the 2023 Terrestrial Very-Long-Baseline Atom Interferometry Workshop hosted by CERN. The workshop brought together experts from around the world to discuss the exciting developments in large-scale atom interferometer (AI) prototypes and their potential for detecting ultralight dark matter and gravitational waves. The primary objective of the workshop was to lay the groundwork for an international TVLBAI proto-collaboration. This collaboration aims to unite researchers from different institutions to strategize and secure funding for terrestrial large-scale AI projects. The ultimate goal is to create a roadmap detailing the design and technology choices for one or more km-scale detectors, which will be operational in the mid-2030s. The key sections of this report present the physics case and technical challenges, together with a comprehensive overview of the discussions at the workshop together with the main conclusions.

hep-ex↗

arXiv2023

From RATs to riches: mitigating anthropogenic and synanthropic noise in atom interferometer searches for ultra-light dark matter

Atom interferometers offer promising new avenues for detecting ultra-light dark matter (ULDM). The exceptional sensitivity of atom interferometers to fluctuations in the local gravitational potential exposes them to sources of noise from human (anthropogenic) and animal (synanthropic) activity, which may obscure signals from ULDM. We characterise potential anthropogenic and synanthropic noise sources and examine their influence on a year-long measurement campaign by AION-10, an upcoming atom interferometer experiment that will be located at the University of Oxford. We propose a data cleaning framework that identifies and then masks anthropogenic and synanthropic noise. With this framework, we demonstrate that even in noisy conditions, the sensitivity to ULDM can be restored to within between 10% and 40% of an atom shot noise-limited experiment, depending on the specific composition of the anthropogenic and synanthropic noise. This work provides an important step towards creating robust noise reduction analysis strategies in the pursuit of ULDM detection with atom interferometers.

astro-ph.CO↗