Global fits of axion-like particles to XENON1T and astrophysical data

Abstract

The excess of electron recoil events seen by the XENON1T experiment has been interpreted as a potential signal of axion-like particles (ALPs), either produced in the Sun, or constituting part of the dark matter halo of the Milky Way. It has also been explained as a consequence of trace amounts of tritium in the experiment. We consider the evidence for the solar and dark-matter ALP hypotheses from the combination of XENON1T data and multiple astrophysical probes, including horizontal branch stars, red giants, and white dwarfs. We briefly address the influence of ALP decays and supernova cooling. While the different datasets are in clear tension for the case of solar ALPs, all measurements can be simultaneously accommodated for the case of a sub-dominant fraction of dark-matter ALPs. Nevertheless, this solution requires the tuning of several a priori unknown parameters, such that for our choices of priors a Bayesian analysis shows no strong preference for the ALP interpretation of the XENON1T excess over the background hypothesis.

Dipole radiation and beyond from axion stars in electromagnetic fields

“…While originally motivated as a solution to the strong CP problem [18][19][20], they are ubiquitous in many high energy physics theories [21][22][23][24]. A variety of experimental efforts are underway to detect axions and axion-like particles (ALPs) in the laboratory [25][26][27][28] and through their unique astrophysical and cosmological signatures [29][30][31][32][33][34][35][36][37][38]. Many of these searches rely upon a coupling of the axion field φ(x, t) to electromagnetism via the interaction g aγ φE • B.…”

BSM Developments and Tools

“…GAMBIT contains a huge library of likelihoods and observables for collider physics [15], dark matter [43], flavour [61], precision observables [62], neutrino physics [63] and cosmology [64], as well as an extensive database of models and sampling strategies, both frequentist and Bayesian [65]. GAMBIT has been employed in studies of a large variety of BSM modes, including SUSY models [66][67][68], Higgs-portal DM models [44,69,70], EFT DM models [71], axion and axion-like particle models [72,73], models with right-handed neutrinos [63], fits of neutral flavour anomalies [74] and cosmological fits of neutrino masses [75].…”

Likelihood analysis of the flavour anomalies and g – 2 in the general two Higgs doublet model

“…GAMBIT is a powerful software framework capable of performing statistical inference studies using constraints from collider [96], dark matter [97], flavour [98] and neutrino [99] physics, as well as cosmology [100]. It has already been used for detailed statistical analyses of a variety of beyond the Standard Model (BSM) models, including supersymmetry [101][102][103], scalar singlet DM [104][105][106][107][108], axion and axion-like particles [109,110], and neutrinos [99,111], as well as an initial analysis of the 2HDM [112]. Our work enhances the FlavBit [98] and Pre-cisionBit [113] modules of GAMBIT to support the GTHDM.…”