Search results for "Axion"
showing 10 items of 121 documents
Search for Hidden-Sector Bosons inB0→K*0μ+μ−Decays
2015
A search is presented for hidden-sector bosons, $\chi$, produced in the decay ${B^0\!\to K^*(892)^0\chi}$, with $K^*(892)^0\!\to K^{+}\pi^{-}$ and $\chi\!\to\mu^+\mu^-$. The search is performed using $pp$-collision data corresponding to 3.0 fb$^{-1}$ collected with the LHCb detector. No significant signal is observed in the accessible mass range $214 \leq m({\chi}) \leq 4350$ MeV, and upper limits are placed on the branching fraction product $\mathcal{B}(B^0\!\to K^*(892)^0\chi)\times\mathcal{B}(\chi\!\to\mu^+\mu^-)$ as a function of the mass and lifetime of the $\chi$ boson. These limits are of the order of $10^{-9}$ for $\chi$ lifetimes less than 100 ps over most of the $m(\chi)$ range, a…
Probing photophobic axion and relaxion dark matter
2021
We investigate the interplay between early universe cosmology and dark matter direct detection, considering axion models with naturally suppressed couplings to photons. In the context of the cosmological relaxation of the electroweak scale, we focus on a scenario of relaxion dark matter, in which the relaxion field constitutes all the observed dark matter relic density and its allowed mass range is fixed to a few keV by construction. In particular, we show that a relaxion particle with mass mϕ=3.0 keV which couples to electrons with gϕ,e=6.8×10−14 is consistent with the XENON1T excess, while accounting for the observed dark matter and satisfying astro/cosmo probes. This scenario uses the el…
Review of dark photon searches
2016
Dark Photons are hypothetical extra-U(1) gauge bosons, which are motivated by a number of astrophysical anomalies as well as the presently seen deviation between the Standard Model prediction and the direct measurement of the anomalous magnetic moment of the muon, (g − 2)μ . The Dark Photon does not serve as the Dark Matter particle itself, but acts as a messenger particle of a hypothetical Dark Sector with residual interaction to the Standard Model. We review recent Dark Photon searches, which were carried out in a global effort at various hadron and particle physics facilities. We also comment on the perspectives for future invisble searches, which directly probe the existence of Light Da…
Direct limits on the interaction of antiprotons with axion-like dark matter
2019
Astrophysical observations indicate that there is roughly five times more dark matter in the Universe than ordinary baryonic matter, with an even larger amount of the Universe's energy content due to dark energy. So far, the microscopic properties of these dark components have remained shrouded in mystery. In addition, even the five percent of ordinary matter in our Universe has yet to be understood, since the Standard Model of particle physics lacks any consistent explanation for the predominance of matter over antimatter. Inspired by these central problems of modern physics, we present here a direct search for interactions of antimatter with dark matter, and place direct constraints on th…
Proposal for a Cosmic Axion Spin Precession Experiment (CASPEr)
2014
We propose an experiment to search for QCD axion and axionlike-particle dark matter. Nuclei that are interacting with the background axion dark matter acquire time-varying CP-odd nuclear moments such as an electric dipole moment. In analogy with nuclear magnetic resonance, these moments cause precession of nuclear spins in a material sample in the presence of an electric field. Precision magnetometry can be used to search for such precession. An initial phase of this experiment could cover many orders of magnitude in axionlike-particle parameter space beyond the current astrophysical and laboratory limits. And with established techniques, the proposed experimental scheme has sensitivity to …
Gravitational wave probes of axionlike particles
2020
We have recently shown that axions and axion-like particles (ALPs) may emit an observable stochastic gravitational wave (GW) background when they begin to oscillate in the early universe. In this note, we identify the regions of ALP parameter space which may be probed by future GW detectors, including ground- and space-based interferometers and pulsar timing arrays. Interestingly, these experiments have the ability to probe axions from the bottom up, i.e. in the very weakly coupled regime which is otherwise unconstrained. Furthermore, we discuss the effects of finite dark photon mass and kinetic mixing on the mechanism, as well as the (in)sensitivity to couplings of the axion to Standard Mo…
Analysis method for detecting topological defect dark matter with a global magnetometer network
2019
Abstract The Global Network of Optical Magnetometers for Exotic physics searches (GNOME) is a network of time-synchronized, geographically separated, optically pumped atomic magnetometers that is being used to search for correlated transient signals heralding exotic physics. GNOME is sensitive to exotic couplings of atomic spins to certain classes of dark matter candidates, such as axions. This work presents a data analysis procedure to search for axion dark matter in the form of topological defects: specifically, walls separating domains of discrete degenerate vacua in the axion field. An axion domain wall crossing the Earth creates a distinctive signal pattern in the network that can be d…
Search for axionlike dark matter with a liquid-state nuclear spin comagnetometer
2019
Physical review letters 122(19), 191302 (2019). doi:10.1103/PhysRevLett.122.191302
New Methods of Axion Dark Matter Detection
2017
In this chapter, I consider new linear effects of axion (pseudoscalar) dark matter in atoms, molecules, nuclei and neutrons.
LHC as an Axion Factory: Probing an Axion Explanation for (g−2)μ with Exotic Higgs Decays
2017
We argue that a large region of so-far unconstrained parameter space for axionlike particles (ALPs), where their couplings to the standard model are of order (0.01-1) TeV^{-1}, can be explored by searches for the exotic Higgs decays h→Za and h→aa in run 2 of the LHC. Almost the complete region in which ALPs can explain the anomalous magnetic moment of the muon can be probed by searches for these decays with subsequent decay a→γγ, even if the relevant couplings are loop suppressed and the a→γγ branching ratio is less than 1.