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The4.2\sigma $4.2\sigma$discrepancy in the(g-2) $(g-2)$of the muon provides a hint that may indicate that physics beyond the standard model is at play. A multi-TeV scale muon collider provides a natural testing ground for this physics. In this paper, we discuss the potential to probe the BSM parameter space that is consistent with solving the(g-2)_{\mu} ${(g-2)}_{\mu }$discrepancy in the language of the SMEFT, utilizing the statistical power provided by fitting event rates collected running at multiple energies. Our results indicate the importance of including interference between the BSM and the SM amplitudes, and illustrates how a muon collider running at a handful of lower energies and with less total collected luminosity can better significantly constrain the space of relevant SMEFT coefficients than would be possible for a single high energy run. 

Abstract We derive purely gravitational constraints on dark matter and cosmic neutrino profiles in the solar system using asteroid (101955) Bennu. We focus on Bennu because of its extensive tracking data and high-fidelity trajectory modeling resulting from the OSIRIS-REx mission. We find that the local density of dark matter is bound byρ_DM ≲ 3.3 × 10^-15 kg/m³ ≃ 6 × 10⁶ ρ̅_DM, in the vicinity of ∼ 1.1 au (where ρ̅_DM ≃ 0.3 GeV/cm³). We show that high-precision tracking data of solar system objects can constrain cosmic neutrino overdensities relative to the Standard Model prediction n̅_ν, at the level ofη ≡ n_ν/n̅_ν ≲ 1.7 × 10¹¹(0.1 eV/m_ν) (Saturn), comparable to the existing bounds from KATRIN and other previous laboratory experiments (withm_νthe neutrino mass). These local bounds have interesting implications for existing and future direct-detection experiments. Our constraints apply to all dark matter candidates but are particularly meaningful for scenarios including solar halos, stellar basins, and axion miniclusters, which predict overdensities in the solar system. Furthermore, introducing a DM-SM long-range fifth force with a strength α̃_Dtimes stronger than gravity, Bennu can set a constraint onρ_DM ≲ ρ̅_DM(6 × 10⁶/α̃_D). These constraints can be improved in the future as the accuracy of tracking data improves, observational arcs increase, and more missions visit asteroids. 

A bstract We investigate a novel interplay between the decay and annihilation of a particle whose mass undergoes a large shift during a first order phase transition, leading to the particles becoming trapped in the false vacuum and enhancing their annihilation rates as the bubbles of true vacuum expand. This opens up a large region of the parameter space where annihilations can be important. We apply this scenario to baryogenesis, where we find that annihilations can be enhanced enough to generate the required baryon asymmetry even for relatively tiny annihilation cross sections with modest CP asymmetries. 

We examine a real electroweak triplet scalar field as dark matter,abandoning the requirement that its relic abundance is determinedthrough freeze out in a standard cosmological history (a situation whichwe refer to as `miracle-less WIMP’). We extract the bounds on such aparticle from collider searches, searches for direct scattering withterrestrial targets, and searches for the indirect products ofannihilation. Each type of search provides complementary information,and each is most effective in a different region of parameter space. LHCsearches tend to be highly dependent on the mass of the SU(2) chargedpartner state, and are effective for very large or very tiny masssplitting between it and the neutral dark matter component. Directsearches are very effective at bounding the Higgs portal coupling, butineffective once it falls below \lambda_{\text{eff}} \lesssim 10^{-3} λ eff ≲ 10 − 3 .Indirect searches suffer from large astrophysical uncertainties due tothe backgrounds and J J -factors,but do provide key information for \sim ∼ 100 GeV to TeV masses. Synthesizing the allowed parameter space, thisexample of WIMP dark matter remains viable, but only in miracle-lessregimes.