Search

Using cosmological hydrodynamical zoom-in simulations, we explore the properties of subhalos in Milky Way analogs that contain a sub-component of Atomic Dark Matter (ADM). ADM differs from Cold Dark Matter (CDM) due to the presence of self interactions that lead to energy dissipation and bound-state formation, analogous to Standard Model baryons. This model can arise in complex dark sectors that are natural and theoretically-motivated extensions to the Standard Model. The simulations used in this work were carried out using GIZMO and utilize the FIRE-2 galaxy formation physics in the Standard Model baryonic sector. For the parameter points we consider, the ADM gas cools efficiently, allowing it to collapse to the center of subhalos. This increases a subhalo's central density and affects its orbit, with more subhalos surviving small pericentric passages. The subset of subhalos that host visible satellite galaxies have cuspier density profiles and smaller stellar-half-mass radii relative to CDM. The entire population of dwarf galaxies produced in the ADM simulations is much more compact than those seen in CDM simulations, unable to reproduce the entire diversity of observed dwarf galaxy structures. Additionally, we also identify a population of highly compact subhalos that consist nearly entirely of ADM and form in the central region of the host, where they can leave distinctive imprints in the baryonic disk. This work presents the first detailed exploration of subhalo properties in a strongly dissipative dark matter scenario, providing intuition for how other regions of ADM parameter space, as well as other dark sector models, would impact galactic-scale observables., Comment: 18 pages, 10 figures, 8 pages of appendices

We study confining dark sectors where the lightest hadrons are glueballs. Such models can provide viable dark matter candidates and appear in some neutral naturalness scenarios. In this work, we introduce a new phenomenological model of dark glueball hadronization inspired by the Lund string model. This enables us to make realistic predictions for dark glueball phenomenology at the LHC for the first time. Our model reproduces the expected thermal distribution of hadron species as an emergent consequence of hadronization dynamics. The ability to predict the production of glueball states heavier than the lightest species significantly expands the reach of long-lived glueball searches in MATHUSLA compared to previous simplified estimates. We also characterize regions of parameter space where emerging and/or semivisible jets could arise from pure-glue dark sectors, thereby providing new benchmark models that motivate searches for these signatures., Comment: 27 pages + appendices + references, 11 + 4 figures; journal edits, including new section on total hadron multiplicities

We examine indirect detection of dark matter that annihilates into dark glueballs, which in turn decay into the Standard Model via a range of portals. This arises if the dark matter candidate couples to a confining gauge force without light flavours, representative of many possible complex dark sectors. Such Hidden Valley scenarios are being increasingly considered due to non-detection of minimal models as well as theoretical motivations such as the Twin Higgs solution to the little hierarchy problem. Study of dark glueballs in indirect detection has previously been hampered by the difficulty of modeling their production in dark showers. We use the recent GlueShower code to produce the first constraints on dark matter annihilating via dark glueballs into the Standard Model across photon, antiproton, and positron channels. We also fit the Galactic Centre Excess and use this observation, combined with other astrophysical constraints, to show how multi-channel observations can constrain UV and IR details of the theory, namely the exact decay portal and hadronization behaviour respectively. This provides unique complementary discovery and diagnostic potential to Hidden Valley searches at colliders. It is interesting to note that thermal WIMPs annihilating to $\mathcal{O}(10~\mathrm{GeV})$ dark glueballs and then the Standard Model via the Twin-Higgs-like decay portal can account for the Galactic Centre Excess while respecting other constraints., Comment: 34 pages, 12 figures. Corrected typos and added references, no changes to conclusions. Extended discussion of relic abundances in Section 2 and dark matter thermal relic cross section in Section 5

In this work, we consider the case of a strongly coupled dark/hidden sector, which extends the Standard Model (SM) by adding an additional non-Abelian gauge group. These extensions generally contain matter fields, much like the SM quarks, and gauge fields similar to the SM gluons. We focus on the exploration of such sectors where the dark particles are produced at the LHC through a portal and undergo rapid hadronization within the dark sector before decaying back, at least in part and potentially with sizeable lifetimes, to SM particles, giving a range of possibly spectacular signatures such as emerging or semi-visible jets. Other, non-QCD-like scenarios leading to soft unclustered energy patterns or glueballs are also discussed. After a review of the theory, existing benchmarks and constraints, this work addresses how to build consistent benchmarks from the underlying physical parameters and present new developments for the PYTHIA Hidden Valley module, along with jet substructure studies. Finally, a series of improved search strategies is presented in order to pave the way for a better exploration of the dark showers at the LHC., Comment: Uniform notation, fixed typos, improved numerical analysis, added references, comments welcome

In an $SU(N_c)$ gauge theory with zero light quark flavours $N_f = 0$, the only hadronic states that form below the confinement scale are composite gluon states called glueballs. These minimal confining sectors arise in many Hidden Valley extensions of the Standard Model, including scenarios that could hold the solution to the dark matter question and the hierarchy problem. Quantitative study of dark glueball phenomenology requires an understanding of pure glue hadronization, which to date is severely lacking. In this work we show that significant progress can be made by combining a perturbative pure glue parton shower with a self-consistent and physically motivated parameterization of the unknown non-perturbative physics, thanks to the modest hierarchy between the glueball mass and the confinement scale. We make our simulation code available as the public GlueShower package, the first glueball generator for Hidden Valley theories, and perform preliminary studies of several glueball production observables, with theoretical uncertainties that take the full range of possible hadronization scenarios into account. We hope this will enable new studies of dark sector phenomenology that were previously inaccessible., Comment: 16 pages, 9 figures. Minor edits in v2, corrected typos and missing references. Added explanation for non-perturbative calculation in Section IV.B.1