Explaining the XENON1T Excess with Luminous Dark Matter

106

Motivated by the recent XENON1T results, we explore various new physics models that can be discovered through searches for electron recoils in $$ \mathcal{O} $$ O (keV)-threshold direct-detection experiments. First, we consider the absorption of axion-like particles, dark photons, and scalars, either as dark matter relics or being produced directly in the Sun. In the latter case, we find that keV mass bosons produced in the Sun provide an adequate fit to the data but are excluded by stellar cooling constraints. We address this tension by introducing a novel Chameleon-like axion model, which can explain the excess while evading the stellar bounds. We find that absorption of bosonic dark matter provides a viable explanation for the excess only if the dark matter is a dark photon or an axion. In the latter case, photophobic axion couplings are necessary to avoid X-ray constraints. Second, we analyze models of dark matter-electron scattering to determine which models might explain the excess. Standard scattering of dark matter with electrons is generically in conflict with data from lower-threshold experiments. Momentum-dependent interactions with a heavy mediator can fit the data with dark matter mass heavier than a GeV but are generically in tension with collider constraints. Next, we consider dark matter consisting of two (or more) states that have a small mass splitting. The exothermic (down)scattering of the heavier state to the lighter state can fit the data for keV mass splittings. Finally, we consider a subcomponent of dark matter that is accelerated by scattering off cosmic rays, finding that dark matter interacting though an $$ \mathcal{O} $$ O (100 keV)-mass mediator can fit the data. The cross sections required in this scenario are, however, typically challenged by complementary probes of the light mediator. Throughout our study, we implement an unbinned Monte Carlo analysis and use an improved energy reconstruction of the XENON1T events.

Section: Jhep01(2021)178mentioning

confidence: 99%

Exploring new physics with O(keV) electron recoils in direct detection experiments

Bloch

Caputo

Essig

et al. 2021

106

“…In order to avoid large corrections to neutrino masses induced by large neutrino magnetic moments, some new symmetries can be introduced [21,26]. Moreover, there are many theoretical attempts to interpret the XENON1T signal assuming new physics beyond the SM such as, boosted dark matter [27][28][29][30][31][32], dark radiation [33,34], anomalous magnetic moment of muon [23,35], inelastic DM-electron scattering [36][37][38][39][40][41], axion-like DM [10,42]. Besides, there are some proposals using a gauged U (1) X extention of the SM, where a gauge boson Z contributes to dark matter (DM) [43][44][45][46][47][48][49][50][51].…”

Section: Jhep12(2020)194mentioning

confidence: 99%

Shedding new light on sterile neutrinos from XENON1T experiment

Shakeri

Hajkarim

Xue

2020

The XENON1T collaboration recently reported the excess of events from recoil electrons, possibly giving an insight into new area beyond the Standard Model (SM) of particle physics. We try to explain this excess by considering effective interactions between the sterile neutrinos and the SM particles. In this paper, we present an effective model based on one-particle-irreducible interaction vertices at low energies that are induced from the SM gauge symmetric four-fermion operators at high energies. The effective interaction strength is constrained by the SM precision measurements, astrophysical and cosmological observations. We introduce a novel effective electromagnetic interaction between sterile neutrinos and SM neutrinos, which can successfully explain the XENON1T event rate through inelastic scattering of the sterile neutrino dark matter from Xenon electrons. We find that sterile neutrinos with masses around 90 keV and specific effective coupling can fit well with the XENON1T data where the best fit points preserving DM constraints and possibly describe the anomalies in other experiments.

“…For DM scattering, rather than absorption, vanilla scenarios are disfavoured due to the observed energy spectrum of the excess. However, exotic DM distribution subcomponents with high velocity components [51][52][53][53][54][55][56][57], exothermic DM scattering [58][59][60][61][62][63][64], or scattering which produces photons [65,66], can provide possible DM scattering explanations. In these cases, if the DM coupling undulates then, irrespective of kinematic details, the scattering rate will undulate, although at present with low statistics the events are consistent with both constant and annual modulations.…”

Section: Jhep11(2020)120mentioning

confidence: 99%

Undulating dark matter

Davighi

McCullough

Tooby-Smith

2020

We suggest that an interplay between microscopic and macroscopic physics can give rise to dark matter (DM) whose interactions with the visible sector fundamentally undulate in time, independent of celestial dynamics. A concrete example is provided by fermionic DM with an electric dipole moment (EDM) sourced by an oscillating axion-like field, resulting in undulations in the scattering rate. The discovery potential of light DM searches can be enhanced by additionally searching for undulating scattering rates, especially in detection regions where background rates are large and difficult to estimate, such as for DM masses in the vicinity of 1 MeV where DM-electron scattering dominantly populates the single electron bin. An undulating signal could also reveal precious dark sector information after discovery. In this regard we emphasise that, if the recent XENON1T excess of events is due to light DM scattering exothermically off electrons, future analyses of the time-dependence of events could offer clues as to the microscopic origins of the putative signal.