arXiv subjects

Le Hoang Nguyen

Publications and source records attributed to Le Hoang Nguyen.

6 recordsLinked to original sources

arXiv2026

The COSMIC WISPers White Paper: The physics case for Weakly Interacting Slim Particles

Axions and other very weakly interacting slim particles (WISPs), with masses below 1 GeV, arise naturally in many extensions of the Standard Model of particle physics. In particular, they could offer a new framework to explain the nature of dark matter and may help address a range of puzzling observations in astrophysics and particle physics. This review provides an overview of ongoing WISP searches and outlines the prospects for the next decade, spanning their theoretical motivation, indirect signatures in astrophysical observations, and dedicated laboratory experiments. It is based on the work carried on by the EU-funded COST Action ``Cosmic WISPers in the Dark Universe: Theory, astrophysics, and experiments'' (CA21106, https://www.cost.eu/actions/CA21106). This network plays a key role in coordinating and supporting WISP searches across Europe, while also contributing to the development of a roadmap aimed at securing European leadership in this research area. It is emphasized that Europe is currently pursuing a rich, diverse, and cost-effective experimental program, with the potential to deliver one or more transformative discoveries.

hep-ph↗

arXiv2025

Permanently magnetized axion-photon conversion surface for direct dark matter searches with BRASS-p

A new method was recently proposed for axion dark matter searches which employs scalable, permanently magnetized, flat conversion surface (or magnetized converter) generating an electromagnetic signal from dark matter particles passing through them. BRASS-p is an experimental setup which applies this method to direct searches of axion/ALP dark matter in the frequency range from 12 to 18 GHz (corresponding to the range of particle mass from 50 to 74 $μ$eV. The conversion surface of BRASS-p will consist of 24 individual panels, each containing a 483mm $\times$ 483mm array of high-grade permanent magnets organized in a pattern capable of generating a magnetic field with an average strength of $\approx$ 0.9 T, for the field component parallel to the surface of the panel. This paper describes the development and optimization of a design for these panels and discusses the resulting sensitivity of BRASS-p measurements to the axion/ALP dark matter.

physics.ins-det↗

arXiv2025

Vector Dark Matter Halo: From Polarization Dynamics to Direct Detection

This study investigates the characteristic polarization formation and evolution of vector dark matter (VDM) in the outer halo of galaxies. By employing numerical simulations, we analyze the behavior of VDM under different initial conditions -- homogeneous, isotropic, and partially polarized. The simulations solve the Schrödinger-Poisson equations, examining the spin density distribution and its evolution during gravitational collapse and halo formation. Our results reveal that VDM forms halos and central Proca stars from homogeneous and isotropic conditions, with the polarization density fluctuation amplitude mirroring VDM matter density. In scenarios with no initial polarization, spin density remains stable in the halo core but fluctuates in outer regions. Partially polarized initial conditions lead to a conservation of total polarization, with increased core polarization resulting in opposite polarization in the periphery. We examine the novel consequences of the partially polarized state for direct detection of dark photons, i.e., VDM kinetically mixed with ordinary photons.

astro-ph.CO↗

arXiv2023

First results from BRASS-p broadband searches for hidden photon dark matter

We discuss first results from hidden photon dark matter searches made with a prototype of the Broadband Radiometric Axion/ALPs Search Setup (BRASS-p) in the range of particle mass of 49.63-74.44 $μ$eV (frequency range of 12-18 GHz). The conceptual design of BRASS and a detailed description of its present prototype, BRASS-p, are given, with a view of the potential application of such setups to hidden photon, axion, and axion-like particle (ALP) dark matter searches using heterodyne detectors in the range of particle mass from 40$μ$eV to 4000$μ$eV (10 GHz to 1 THz). Pioneering measurements made with BRASS-p achieve the record sensitivity of (0.3--1.0)$\times$$10^{-13}$ to the kinetic mixing between the normal and hidden photons, assuming the dark matter is made entirely of unpolarized hidden photons. Based on these results, a discussion of further prospects for dark matter searches using the BRASS-p apparatus is presented.

hep-ex↗

arXiv2019

First results from the WISPDMX radio frequency cavity searches for hidden photon dark matter

The origin of non-baryonic Dark Matter remains elusive despite ongoing sensitive searches for heavy, thermally produced dark matter particles. Recently, it has been shown, that non-thermally produced vector bosons (sometimes called hidden photons) related to a broken U(1) gauge symmetry are among the possible WISP (weakly interacting slim particles) dark matter candidates. The WISP Dark Matter eXperiment (WISPDMX) is the first direct hidden photon dark matter search experiment probing the particle masses within the 0.8-2.07 $μ$eV range with four resonant modes of a tunable radio frequency cavity and down to 0.4 $n$eV outside of resonance. In this paper, we present the results from the first science run of WISPDMX comprising 22000 broadband spectra with a 500 MHz bandwidth and a 50 Hz spectral resolution, obtained during 10-second integrations made at each individual tuning step of the measurements. No plausible dark matter candidate signal is found, both in the individual spectra reaching minimum detectable power of $8^{-19}$ Watt and in the averaged spectrum of all the measurements with the minimum detectable power of $5^{-22}$ Watt attained for a total of 61 \hours of data taking. Using these spectra, we derive upper limits on the coupling constant of the hidden photon at the levels of $10^{e-13}$ for the resonant frequency ranges and $10^{-12}$ for broadband mass range 0.2-2.07 $μ$eV, and steadily increasing at masses below 0.2$μ$eV.

hep-ex↗

arXiv2015

WISPDMX: A haloscope for WISP Dark Matter between 0.8-2 $μ$eV

Weakly interactive slim particles (WISPs), including the QCD axion, axion-like particles (ALPs), and hidden photons, are considered to be strong candidates for the dark matter carrier particle. The microwave cavity experiment WISPDMX is the first direct WISP dark matter search experiment probing the particle masses in the 0.8-2.0 $μ$eV range. The first stage of WISPDMX measurements has been completed at nominal resonant frequencies of the cavity. The second stage of WISPDMX is presently being prepared, targeting hidden photons and axions within 60\% of the entire 0.8-2.0 $μ$eV mass range.

physics.ins-det↗