Dark Matter Beyond the Weak Scale IV

Europe/London
Description
Dark Matter Beyond the Weak Scale (or BeyondWimps for short) is a workshop established in the UK to build and expand connections between the theoretical community and the new experiments exploring dark matter beyond the traditional weak scale WIMPs.
 
This is the fourth instalment of the workshop, where we return to Liverpool after previous meetings in Oxford, Durham, and Liverpool. For information about these previous workshops, see https://beyondwimps.com/.
 
Organised by:
Djuna Croon (Durham University),
Edward Hardy (University of Oxford),
Juri Smirnov (University of Liverpool).
 
Confirmed speakers: see timetable
    • 14:00 14:45
      From Atoms to Machine-Learned Molecules: Dark Matter Detection at Low Energies 45m
      Speaker: Jack Shergold
    • 14:45 15:30
      Probing sub-GeV dark matter scattering through sidereal modulation 45m
      Speaker: Tetiana Kozynets
    • 15:30 16:00
      Coffee break 30m
    • 16:00 16:45
      Beyond WIMPs in Direct Dark Matter searches (xenon realm) 45m
      Speaker: Sergey Burdin
    • 09:30 10:15
      Dark matter at the smallest scales: New signatures of particle dark matter 45m

      I will present prompt cusps, a recently identified class of compact dark matter structures with ρ∝r^-1.5 density profiles that form at the onset of structure formation and persist at halo centers. These systems enable new constraints on warm dark matter from dwarf galaxy kinematics, strengthen limits on annihilating dark matter, and offer detection prospects for general cold dark matter models. Next, I will discuss how enhanced primordial perturbations can form halos during the radiation era that are compact enough to be detected with microlensing. Finally, I will present results on primordial black hole (PBH) dark matter from a new cosmological simulation that fully resolves individual PBH dynamics. Interactions randomize binary orbits, dramatically altering
      gravitational-wave predictions, while a hot dark matter component emerges that suppresses structure growth up to galactic scales.

      Speaker: M. Sten Delos
    • 10:15 11:00
      WIMP Dark Matter and New-Physics Interpretations of the PTA Signal are Incompatible 45m

      Explaining the large amplitude of the nano-Hertz stochastic gravitational-wave background observed by pulsar timing arrays (PTAs) typically requires extremely energetic primordial sources. Such mechanisms generically produce large curvature perturbations, which subsequently collapse into ultra-compact mini-halos (UCMHs). If
      dark matter consists of weakly interacting massive particles (WIMPs), the high densities inside UCMHs lead to efficient dark-matter annihilation, generating potentially observable photon and neutrino fluxes. I will show that, for several proposed primordial explanations of the PTA signal, including curvature-peak scenarios, first-order
      phase transitions, and domain-wall dynamics, the predicted fluxes from the resulting UCMH population exceed current observational bounds. These results therefore place strong tension between WIMP dark matter and new-physics interpretations of the PTA signal.

      Speaker: Yann Gouttenoire
    • 11:00 11:30
      Coffee break 30m
    • 11:30 12:15
      Astrophysical probes of ultralight particles: pulsar spindown, birefringence, and superradiance 45m
      Speaker: Tanmay Poddar
    • 12:15 13:45
      Lunch 1h 30m
    • 13:45 14:30
      Community discussion on navigating an evolving funding landscape 45m
    • 14:30 15:15
      Ultralight Dark Matter at Colliders and Quantum Sensors 45m
      Speaker: Martin Bauer
    • 15:15 15:45
      Coffee break 30m
    • 15:45 16:30
      Electroweak Dark Matter: Generalised Framework and Direct and Indirect Search Prospects 45m
      Speaker: Spencer Griffith
    • 16:30 17:15
      Status report on the QSHS axion search 45m
      Speaker: Ed Daw
    • 09:30 10:15
      Dark Showers from Sneaky Dark Matter 45m
      Speaker: Fatemeh Elahi
    • 10:15 10:45
      Coffee break 30m
    • 10:45 11:30
      Probing the nature of dark matter with galaxies and Black Holes 45m
      Speaker: Malcolm Fairbairn
    • 11:30 12:15
      Stellar cooling limits on dark dimensions 45m

      Nearly 30 years since the ADD proposal to solve the hierarchy problem via large extra dimensions, such scenarios have seen a resurgence in interest in the context of the ‘dark dimension’ - an extra dimension of micron scale motivated by the swampland program. We will begin by reviewing the features of the dark dimension, including the possibility that dark matter could consist of Kaluza-Klein gravitons. We will then undertake a systematic study of the model-independent astrophysical constraints on large extra dimensions. These arise from stellar cooling through emission of Kaluza-Klein gravitons. Setting up the calculation from first principles in the context of thermal field theory leads to the identification of a process with no zero-temperature analogue: resonant plasma mixing. After studying a range of previously overlooked processes in red giants, horizontal branch stars, neutron stars, and supernovae, we find that for two or more extra dimensions the leading bounds come from the cooling of supernova 1987A.

      Speaker: Henry Stubbs
    • 12:15 13:45
      Lunch 1h 30m
    • 13:45 14:30
      Stellar microlensing constraints on Primordial Black Holes 45m
      Speaker: Anne Green
    • 14:30 15:15
      Searching for Dark Matter Microlensing Signals with Machine Learning 45m
      Speaker: Miguel Crispim Romao
    • 15:15 17:15
      Discussion session / BeyondWimps report 2h
    • 15:15 17:15
      Exploring Liverpool 2h
    • 19:00 21:00
      Conference dinner 2h The Philharmonic dinning rooms

      The Philharmonic dinning rooms

      36 Hope St, Liverpool L1 9BX
    • 09:15 10:00
      Talk 45m
      Speaker: Ashlea Kemp
    • 10:00 10:45
      Cosmological tests of the nature of dark matter 45m

      The fundamental nature of dark matter so far eludes direct detection experiments, but it has left its imprint in the cosmic large-scale structure. Disentangling this imprint requires accurate modelling of structure formation in non-standard dark matter models, careful handling of astrophysical uncertainties and consistent observations in independent cosmological probes. I will review a multi-scale, multi-epoch test of the nature of dark matter combining state-of-the-art modelling with observations of the cosmic microwave background, galaxy clustering (redshift z < 2), the Lyman-alpha forest (2 < z < 5) and the high-redshift (z > 5) galaxy UV luminosity function from the Hubble and Webb Space Telescopes. I will discuss the extent to which cosmological data are more consistent in the presence of ultra-light axion dark matter. I will further discuss prospects for adjudicating the viability of axion models in observations of the galaxy and Milky Way sub-structure distributions by the transformative Vera C. Rubin Observatory.

      Speaker: Keir Rogers
    • 10:45 11:15
      Coffee break 30m
    • 11:15 12:00
      Beyond WIMPs: Perspectives on Beyond Elastic Recoil Searches 45m
      Speaker: Jocelyn Monroe