Related papers: Probing sub-GeV leptophilic dark matter at Belle I…
A small component of dark matter (DM) that is strongly interacting with the standard model sector is consistent with various experimental observations. Despite the small abundance, strongly-interacting DM can lead to pronounced signals in…
We investigate the power of low-energy, high-luminosity electron--positron colliders to probe hidden sectors with a mass below ~10 GeV that couple to Standard Model particles through a light mediator. Such sectors provide well-motivated…
Light pseudoscalars interacting pre-dominantly with Standard Model gauge bosons (so-called axion-like particles or ALPs) occur frequently in extensions of the Standard Model. In this work we review and update existing constraints on ALPs in…
In a broad class of consistent models, MeV to few-GeV dark matter interacts with ordinary matter through weakly coupled GeV-scale mediators. We show that a suitable meter-scale (or smaller) detector situated downstream of an electron…
A vector portal between the Standard Model and the dark sector is a predictive and compelling framework for thermal dark matter. Through co-annihilations, models of inelastic dark matter (iDM) and inelastic Dirac dark matter (i2DM) can…
We consider the possibility that dark matter (DM) only interacts with the Standard Model leptons, but not quarks at tree level, and analyze the future lepton collider prospects of such leptophilic DM in the monophoton and mono-$Z$ (both…
Traditional direct searches for dark matter, looking for nuclear recoils in deep underground detectors, are challenged by an almost complete loss of sensitivity for light dark matter particles. Consequently, there is a significant effort in…
We investigate the prospects for detecting light leptophilic dark sectors with a missing-momentum experiment at NA64 running in muon mode. In particular, we consider models in which dark matter connects to the visible sector through a…
Recently, the Belle II collaboration announced the first measurement of $\mathcal B(B^+\to K^+\nu\bar\nu)$, which is found to be about $2.7\sigma$ higher than the SM prediction. We decipher the data with two new physics scenarios: the…
We propose a new search for light scalar singlets in rare meson decays. For tiny interactions, the scalar is long-lived at detector scales and decays into displaced pairs of leptons or light mesons. We show that Belle II has a remarkable…
The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric $e^+e^-$ collider. The design luminosity of the machine is 8$\times10^{35}$ cm$^{-2}$s$^{-1}$ and the Belle II…
Belle II is an experiment operating at the intensity frontier. Over the next decades, it will record the decay of billions of bottom mesons, charm hadrons, and tau leptons produced in 10 GeV electron-positron collisions at the SuperKEKB…
Inelastic dark matter scenarios have attracted considerable attention in contemporary particle physics. In this study, we investigate the phenomenology of sub-GeV inelastic dark matter interacting via a lepton-specific scalar portal. By…
Thermal dark matter models with particle $\chi$ masses below the electroweak scale can provide an explanation for the observed relic dark matter density. This would imply the existence of a new feeble interaction between the dark and…
We study the direct detection prospects for a representative set of simplified models of sub-GeV dark matter (DM), accounting for existing terrestrial, astrophysical and cosmological constraints. We focus on dark matter lighter than an MeV,…
Extensions of the Standard Model with masses at or below the GeV scale are motivated by searches for dark matter and precision measurements in the quark and lepton flavour sectors, including that of the muon anomalous magnetic moment. An…
Dark matter particles that couple primarily to leptons are only weakly constrained by data from direct detection experiments and the LHC. However, models of this kind necessarily generate effective four-lepton contact interactions at the…
Dark Matter particles with inelastic interactions are ubiquitous in extensions of the Standard Model, yet remain challenging to fully probe with existing strategies. We propose a series of powerful searches at hadron and lepton colliders…
We propose a new ``disappearing positron track'' channel at Belle II to search for dark matter, in which a positron that is produced at the primary interaction vertex scatters with the electromagnetic calorimeter to produce dark matter…
We reappraise the viability of asymmetric dark matter (ADM) realized as a Dirac fermion coupling dominantly to the Standard Model fermions. Treating the interactions of such a DM particle with quarks/leptons in an effective-interactions…