Nordic meeting on Dark Matter searches

Europe/Zurich
M006 (Western Norway University of Applied Sciences)

M006

Western Norway University of Applied Sciences

Inndalsveien 28, 5063 Bergen
Description

Welcome to the Nordic meeting on Dark Matter searches

22nd to 24th of May 2024 in Bergen, Norway. 

This meeting will bring together physicists from different fields of Dark Matter research. It will cover the topics of direct and indirect detection as well as Dark Matter searches at colliders. Only a coherent understanding of the results from all fields will allow us to pin-point the nature of Dark Matter and help to understand this important building block of our Universe.

We envision an event for networking and giving especially early career researchers and students the opportunity to present their results and learn about the latest developments in the field.  

Invited speakers:
Laura Baudis (University of Zurich) - Direct dark matter detection
Torsten Bringmann (University of Oslo) - Dark matter models     
Giacomo D'Amico (University of Bergen) - Indirect dark matter searches
Sukanya Sinha (University of Manchester) - Dark matter searches at colliders
Knut Morå (Columbia University) - Direct detection and statistical interpretation                           

International advisory committee: 
Jan Conrad (Stockholm University)     
Steen Hansen (University of Copenhagen)       
Katri Huitu (University of Helsinki)
Christian Ohm (KTH Royal Institute of Technology)                             

Local Organisation Committee:
 Therese Berge Sjursen
 Julia Djuvsland
 Steffen Maeland
 Giacomo D'Amico
 Aurora Grefsrud
 Igor Slazyk  
 Trygve Buanes  
 Dag Toppe Larsen

Organisation Committee Contact
    • 8:45 AM 9:00 AM
      Registration and welcome 15m M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Speakers: Julia Isabell Djuvsland (University of Bergen (NO)), Dr Steffen Maeland (Western Norway University of Applied Sciences), Therese Sjursen (Western Norway University of Applied Sciences (No))
    • 9:00 AM 10:30 AM
      Dark matter searches at colliders M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Sukanya Sinha (University of Manchester (GB))
    • 10:30 AM 11:00 AM
      Coffee break 30m M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
    • 11:00 AM 12:00 PM
      Contributed Talks M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Dr Steffen Maeland (Western Norway University of Applied Sciences)
      • 11:00 AM
        A search for heavy neutral gauge bosons and dark-sector particles with the ATLAS detector 30m

        We present a search for a new neutral vector boson ($Z^\prime$) produced in association with dark states that do not interact via the Standard Model interactions. The search is performed using proton-proton collisions at $\sqrt{s}=13~$TeV corresponding to an integrated luminosity of $140~$fb$^{-1}$ recorded by the ATLAS detector at the Large Hadron Collider. The $Z^\prime$ boson is assumed to decay to a pair of same-flavour light leptons ($e^{+} e^-$ or $\mu^{+} \mu^{-}$), while the dark particles escape detection, meaning that the targeted experimental signature is a resonance in the dilepton invariant-mass spectrum and large missing transverse momentum.

        Two signal benchmark models, referred to as dark-Higgs and light-vector, are used to optimise the search, and a set of signal regions are defined as bins in the E$_{\text{T}}^{\text{miss}}$ significance variable. The results of the search are obtained by scanning across the dilepton invariant-mass spectrum in each signal region. No significant excess over the Standard Model prediction is observed. Cross-section limits are set on the considered benchmark scenarios, and on the coupling of the $Z^\prime$ to leptons, for $Z^\prime$ masses between $200$ GeV and $1$ TeV.

        The signal benchmarks used for the search are not required to reproduce the observed dark-matter relic density, and some additional studies are performed to evaluate the potential for tuning the models to yield realistic relic density predictions. We also consider the impact of constraints from other relevant searches on the models, and discuss planned extensions of the search and its interpretations, for example in terms of more model-independent exclusion limits.

        Speaker: Even Simonsen Haaland (University of Oslo (NO))
      • 11:30 AM
        Hunting the Supersymmetric Dark Matter with taus 30m

        Supersymmetry is one of the best-motivated proposals for physics beyond the Standard Model. One of the primary motivations for the supersymmetry rests on the observation that the LSP (lightest supersymmetric particle) in R-parity conserving models is massive, naturally neutral and stable. This synergy of properties casts the LSP as an excellent candidate for the dark matter (DM). The stau (superpartner of the 3rd-generation fermion 𝜏) is predicted to be relatively light in various SUSY scenarios and models with light staus can lead to a dark-matter relic density consistent with the cosmological observations. Decay of staus leads to 𝜏-rich final states with LSP appearing as missing transverse momentum (MET) in the system. Therefore, we explore the possibility of DM production at LHC in the final states with tau+MET+jets events. This talk reports on the MET trigger efficiency and signal optimization studies for Squarks/Gluinos production in the framework of simplified models.

        Speaker: Sohaib Hassan (University of Bergen (NO))
    • 12:00 PM 1:30 PM
      Lunch 1h 30m Godt Brød, Inndalsveien 6

      Godt Brød, Inndalsveien 6

    • 1:30 PM 3:00 PM
      Dark matter models M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Torsten Bringmann (University of Oslo (NO))
    • 3:00 PM 3:30 PM
      Coffee break 30m M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
    • 3:30 PM 5:00 PM
      Contributed Talks M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Dr Trygve Buanes (Western Norway University of Applied Sciences (NO))
      • 3:30 PM
        Global fits of simplified dark matter models with GAMBIT 30m

        Simplified dark matter models are a form of effective theory that offer search targets for both low-energy dark matter and high-energy collider experiments. In this talk I will discuss several global fits of simplified dark matter models with GAMBIT, focussing on four different models all coupled to the Standard Model by a spin-1 vector mediator. For one of these models, I will also discuss how unitarity violation in the high-energy limit of the theory impacts global fits.

        Speaker: Christopher Chang
      • 4:00 PM
        Asymmetries in invisible Dark Matter mediator production associated with $t\bar{t}$ final states 30m

        In this paper, we propose two sets of different CP-sensitive observables inspired by the Higgs production in association with the top quark. We employ a Dark Matter simplified model that couples a scalar particle with three generation fermions with a mass equal to that of the top quark. The reconstruction of the kinematic variables is presented at NLO accuracy for events associated with this massive scalar particle, which is assumed to be vanishing to invisible decays in a detector such as ATLAS. We build these observables by taking advantage of the similarity between the scalar coupling with the top quark and the factorization theorem in the total scattering amplitude, in order to represent the basis in which the phase space is parameterized. A twofold approach employs the direct implementation of the four-momentum phase space measure in building CP sensitive observables such as $b_{2}$ for the Higgs, and the spin polarization of the top-quark decays in the narrow width approximation for the employed model. We studied the asymmetries of these distributions to test for any improvement in increasing the exclusion region for the $g_{u_{33}}^S-g_{u_{33}}^P$ parameters associated with this vanishing scalar particle. We have found no significant effect in the exclusion limits by using the forward-backward asymmetry distributions and the full shaped ones. The best limits obtained for $g_{u_{33}}^S$ at NLO accuracy were obtained: $b_{2}:[-0.0425, 0.0475]$ $n_{4}: [-0.0450, 0.0450] $ for an invisible scalar with a mass of 10$^{-2}$~GeV for a luminosity of 300 fb$^{-1}$ expected for the end of RUN 3 of the LHC.

        Speaker: Rui Miguel Silva (Universidade do Minho/CFUMUP,LIP)
    • 9:00 AM 10:30 AM
      Indirect Dark Matter Detection M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Giacomo D'Amico
    • 10:30 AM 11:00 AM
      Coffee break 30m M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
    • 11:00 AM 12:00 PM
      Contributed Talks M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Julia Isabell Djuvsland (University of Bergen (NO))
      • 11:00 AM
        Indirect detection of minimal dark matter quintuplet 30m

        In the wake of the recent computation of bound state formation cross-section for minimal dark matter quintuplet that introduces a new signal for indirect detection, we go through 15-year Fermi-LAT data looking for this new line. We examine Fermi-LAT data from the galactic center to assess its capability to detect or rule out a potential line arising from bound-state formation. Our findings reveal that the Fermi-LAT data effectively rules out the MDM 5plet. Moreover, we study the prospects of future Cherenkov Telescope Array for the detection of the annihilation line. We find that it must be possible to detect or exclude minimal dark matter quintuplet by O(100) hour observation of particular dwarf spheroidal galaxies.

        Speaker: Mr Mohammad Aghaie (University of Pisa)
      • 11:30 AM
        Measuring the Dark Matter Content of Dwarf Spheroidal Galaxies and Globular Clusters 30m

        Dark matter (DM), a large (~85%) non-baryonic and non-relativistic
        component of the matter density of the Universe, likely consists of one
        or several so-far undetected particles hypothesized in theories beyond
        the Standard Model (SM). One of the most promising approaches to shed
        light on the nature of DM particles is to search for signatures of their
        annihilation or decay into SM particles - among which very-high energy
        gamma-rays - from regions of the sky believed to be highly DM dominated,
        such as the Galactic Center, the clusters of galaxies and local compact
        objects such as the dwarf spheroidal galaxies (dSphs) and some globular
        clusters around the Milky Way. In this context, the latter two are among
        the most promising observational targets due to their relative proximity
        and lack of astrophysical background sources, and are therefore
        paramount targets to be pointed at with current (e.g., MAGIC) and
        next-generation (e.g., CTA) Cherenkov telescopes to detect gamma-rays
        produced by DM interactions or at least constrain the particle DM
        parameter space. In this contribution, I will present new determinations
        of the DM amount (i.e. the astrophysical factors for DM annihilation and
        decay) in dSph and globular cluster halos obtained through the MCMC
        Jeans analysis of their brightness and kinematic data through the CLUMPY
        software. I will also discuss the systematic uncertainties affecting the
        calculation of such quantities.

        Speaker: Francesco G. Saturni
    • 12:00 PM 1:00 PM
      Lunch 1h Cafeteria 2nd floor

      Cafeteria 2nd floor

    • 1:00 PM 2:30 PM
      Data analysis methods and statistical interpretation M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Dr Knut Morå (Columbia University)
    • 2:30 PM 7:00 PM
      Excursion to city centre and local view point mount Floyen Fløibanen, Vetrlidsallmenningen 23A

      Fløibanen, Vetrlidsallmenningen 23A

    • 7:00 PM 9:00 PM
      Conference Dinner 2h Fløirestauranten

      Fløirestauranten

      For the funicular up to the restaurant, we meet at the bottom station at (Vetrlidsallmenningen 23A) at 18.20.

      For those who wish to walk up, we meet at the funicular station at 18.00 and walk from there.

      To get down again after dinner, we walk or take the funicuar at a convenient time.

      https://www.floyen.no/en/food-and-beverage/floien-folkerestaurant/

    • 9:00 AM 10:30 AM
      Direct Dark Matter Detection M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Laura Baudis (University of Zurich (CH))
    • 10:30 AM 11:00 AM
      Coffee break 30m M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
    • 11:00 AM 12:30 PM
      Contributed Talks M006

      M006

      Western Norway University of Applied Sciences

      Inndalsveien 28, 5063 Bergen
      Convener: Igor Slazyk (University of Bergen (NO))
      • 11:00 AM
        New results for searches of exotic decays with NA62 in beam-dump mode 30m

        The NA62 experiment at CERN took data in 2016–2018 with the main goal of measuring the $K^+ \rightarrow \pi^+ \nu \bar\nu$ decay. In this talk we report on the search for visible decays of exotic mediators from data taken in "beam-dump" mode with the NA62 experiment. NA62 can be run as a "beam-dump" experiment by removing the kaon production target and moving the upstream collimators into a "closed" position. In this configuration 400 GeV protons are dumped on an absorber and New Physics (NP) particles, including dark photons, dark scalars and axion-like particles, may be produced and reach a decay volume beginning 80 m downstream of the absorber. More than $10^{17}$ protons on target have been collected in "beam-dump" mode by NA62 in 2021. Recent results from analysis of this data, with a particular emphasis on Dark Photon and Axion-like particle Models, are presented. We also report new results on the first NA62 search for long-lived NP particles decaying in flight to hadronic final states based on a blind analysis of a sample of $1.4 \times 10^{17}$ protons on dump collected in 2021.

        Speaker: Ilaria Rosa (Universita Federico II e INFN Sezione di Napoli (IT))
      • 11:30 AM
        Detecting dark matter around massive black holes using gravitational waves 30m

        Gravitational waves could be used as a novel probe of dark matter. In compact binary mergers with extreme mass-ratios, the gravitational interaction between the secondary object and its dark matter environment can speed up the inspiral, leaving an imprint on the gravitational waveform. With the recently approved LISA space interferometer, many extreme mass ratio signals will become detectable. A positive detection of a dark matter imprint in these signals requires extremely high dark matter densities known as “spikes”, the formation of which is closely linked to the dark matter particle model. Such a detection would thus constrain the current model landscape. In this talk, I will start with the current state of the imprint analysis and of spike models. I will then present the work done in my master’s thesis, for which I looked into the next evolution of CDM spike models that take realistic formation and growth history into account. Finally, I will discuss the impact of realistic models on spike detectability.

        Speaker: Renske Wierda (KTH Royal Institute of Technology (SE))
      • 12:00 PM
        What blazar jets tell us about axion-like particles 30m

        Prompt emissions from TeV blazars pair produce on the extragalactic background light and the resulting electrons and positrons then undergo inverse Compton scattering, giving rise to secondary gamma-rays. The non-observation of such reprocessed emission implies a suppression of cascades from TeV blazars. In addition to the deflection of the electron-positron pairs off the line of sight by the extragalactic magnetic field, plasma instabilities can transport some of the energy away from the pair beam and into the intergalactic medium. In this talk, I will discuss how certain dark matter candidates such as axion-like particles can affect the evolution of blazar jets and vice versa.

        Speaker: Oindrila Ghosh (Stockholm University & the Oskar Klein Centre)
    • 12:30 PM 2:00 PM
      Lunch 1h 30m Cafeteria 2nd floor, K1

      Cafeteria 2nd floor, K1