Welcome and general overview of the workshop week.
Meta-information on schedules and resources.
We review nonrelativistic effective field theories for
quarkonium at and out of equilibrium emphasizing their utility also in
describing dark matter pairs near threshold and their evolution in
the early universe.
In this talk, my objective is to present the phenomenology of Electroweak multiplets as potential Dark Matter (DM) candidates in the coming years, with a specific focus on detection possibilities at the muon collider. To begin, I will delve into the thermal production mechanism in the early Universe and provide an overview of the current phenomenological landscape concerning the search for...
If dark matter couples to force mediators that are much lighter than itself, then its interactions manifest as long-ranged. This gives rise to non-perturbative effects, including the existence of bound states. The formation of stable or metastable dark matter bound states can affect the dark matter phenomenology very significantly, including the dark matter relic density, indirect and direct...
We reexamine the consequences of perturbative unitarity on dark matter freeze-out when both Sommerfeld enhancement and bound state formation affect dark matter annihilations. At leading order (LO) the annihilation cross-section is infrared dominated and the connection between the unitarity bound and the upper bound on the dark matter mass depends only on how the different partial waves are...
The formation and decay of metastable dark matter bound states in the early universe can deplete the dark matter abundance, thereby affecting the predicted couplings and mass. The efficacy of the effect is suppressed by the ionisation and excitations of bound states due to the ambient radiation. While existing calculations take into account the thermal radiation, the dynamics of Hydrogen...
A long-range force between dark matter particles makes significant impacts on dark matter phenomenology.
It enhances the annihilation cross section at the late Universe (Sommerfeld enhancement), which affects the prospects for detecting annihilation products (indirect detection experiments).
It also leads to a large self-scattering cross section, which forms a significant core in dark matter...
We examine the Sommerfeld enhancement in dark matter pair annihilation, scrutinizing p- and higher ℓ-wave annihilations. We focus on the Yukawa potential, noting unexpected velocity scaling and resonant behavior, attributed to the presence of quasi-bound states. We provide a quantum mechanical explanation for the phenomenon and for its features using the WKB approximation. We examine the...
We consider the resummation of large electroweak Sudakov logarithms for the annihilation of neutralino DM with $\mathcal{O}$(TeV) mass to high-energy photons in the minimal supersymmetric standard model, extending previous work on the minimal wino and Higgsino models. We find that NLL resummation reduces the yield of photons by about 20% for Higgsino-dominated DM at masses around 1 TeV, and up...
The idea that dark matter is nothing more than a “heavy neutrino” that froze out after reheating has long been a seductive one. Indirect detection experiments are just now entering an era where the simplest candidate thermal relic models can be excluded. We will survey the status of current & near-future observations of the galactic center and dwarf spheroidal galaxies to rule on...
The evidence for dark matter is perhaps of the strongest call for new physics. On top of being desirable from the phenomenological and observational points of views, the possibility of a richer dark sector, that comprises more than one particle, is fairly common in many DM models. The dark particles can enjoy their own hidden forces, which are far less constrained than the interactions between...
For a quantitative investigation on the time evolution of heavy thermal dark matter at and after thermal freeze-out, near-threshold processes need to be taken into account which have a large impact on the observed dark matter relic abundance. We study the recoil effect of heavy dark matter pairs in a thermal bath and compute the thermal rates of dark matter fermion-antifermion pairs in the...
In this work, we address the impact of the thermal Debye mass 𝑚𝐷 scale on the bound-state formation and ionization (dissociation) in the dark sector in the Early Universe. We focus on heavy dark fermions (with mass 𝑚) charged under a 𝑈(1)𝑑 group coupling dark matter to dark photons and dark light fermions with the coupling constant 𝛼=𝑔2/4𝜋. We determine the effect of the HTL resummation on the...
Indirect detection is one of the most powerful methods to search for annihilating dark matter. In this work, we investigate the impact of non-perturbative effects in the indirect detection of dark matter. For this purpose we utilize a minimal model consisting of a fermionic dark matter candidate in the TeV mass range that interacts via scalar- and pseudo-scalar interactions with a massive...
Chair: Peter Vander Griend,
Panel: Kalliopi Petraki, Matthew Baumgart, Jan Heisig, Benoît Assi
Topics:
1. shared tools between quarkonia and dark matter communities
(a) How are relativistic quantum field theoretic, nonrelativistic effective field theoretic and quantum mechanical treatments used in the quarkonium and dark matter (DM) communities? What are the advantages of each approach...
I review how strongly coupled potential nonrelativistic QCD (pNRQCD) and lattice
can describe quarkonium in the confinement region. A new effective field theory called Born Effective Field Theory (BOEFT) is able also to describe the new XYZ exotics discovered in the sector with two heavy quarks. I discuss the implications
of these findings for nonperturbative scenarios of DM.
To describe cosmological phase transitions perturbatively, scale hierarchies are required. At finite temperature such a hierarchy is provided naturally for gauge theories. If this hierarchy is not accounted for, uncertainties of phase transition thermodynamic parameters can be large due to infrared sensitivity and slow perturbative convergence faced by scalar bosons.
To reliably describe...
Quarkonia are versatile probes to study the hot primordial nuclear matter. Their dynamics are usually described through models based on resummed perturbative QCD, AdS, and effective field theories. It is not immediately obvious to which extent these models can describe the strongly coupled media most relevant to phenomenology. The lattice provides nonperturbative input and constraints to such...
Heavy probes are an excellent tool to study the quark gluon plasma formed at the heavy ion collision experiments. The lattice results of the transport coefficients provide an important input to phenomenological models explaining these experiments. Especially interesting transport property studied a lot in the recent years, is the diffusion of heavy quarks and quarkonium. Such diffusion...
Suppression of open heavy flavors and quarkonia in heavy-ion collisions is among the most informative probes of the quark-gluon plasma (QGP). Interpreting the full wealth of data obtained from the collision events requires a precise understanding of the evolution of heavy quarks and quarkonia as they propagate through the nearly thermal and strongly coupled plasma. Only in the past few years,...
By tracking the arrival times of radio pulses from a collection of pulsars in the Milky Way, several pulsar timing array collaborations have found evidence for a background of gravitational waves permeating our galaxy. In this talk, I will present this evidence, review possible cosmological interpretations of the signal, and discuss ways to discriminate between the signals emitted by these...
We consider strongly interacting dark matter candidates as composite states of Nf=2 fermions charged under a dark Sp(4) gauge group in the fundamental representation. We calculate correlation functions of two pseudo-Nambu-Goldstone-bosons on the lattice and present first results of the scattering phase shift in the isospin-2 channel. We calculate the self-interaction cross-section in the...
Chair:
N. Brambilla
Panel:
J. Ghiglieri, E. Kuflik, E. Morgante, M. Redi, B. Scheihing J. Weber, G. White
I will review recent developments of applying the open quantum system framework to understand quarkonium dynamics inside the quark-gluon plasma. I will discuss three temperature regions that are relevant to the current relativistic heavy ion collision experiments. I will focus on how medium properties are encoded in the transport equations for each temperature region and discuss how to...
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In this talk, I will review the status and recent advances in the description of quarkonium suppression using the formalism of open quantum systems.
For decades, bound states of heavy quarks have served as ideal experimental and theoretical probes of the medium formed in heavy ion collisions. Specifically, suppression of heavy quarkonium states in heavy ion relative to proton-proton collisions was postulated as a strong signal of the formation of a deconfined quark gluon plasma (QGP). More recently, the use of effective field theories...
Ab-initio simulations of multiple heavy quarks propagating in a Quark-Gluon Plasma are computationally difficult to perform due to the large dimension of the space of density matrices. Neural Network Quantum States offer a promising approach to overcoming this numerical difficulty by variationally parametrising quantum states with parameters of a Neural Network. In this talk, I present proof...
The existence of a dark matter (DM) model with a rich dark sector could be the reason why WIMP DM has evaded its detection so far. For instance, colored co-annihilation naturally leads to the prediction of heavier DM masses. Moreover, non-perturbative effects such as Sommerfeld corrections and bound state formation must be considered to accurately predict the DM relic abundance. In the context...
Simplified t-channel dark matter models serve as a versatile and well-motivated framework for rich
dark sectors that are widely studied by ongoing experimental and theoretical efforts. In this work,
we investigate the impact of non-perturbative effects on the dark matter relic abundance for two
representative models of this kind of models, focusing on regions of parameter space where...
The nature of dark matter in our Universe remains one of the most compelling inquiries in fundamental physics today. While weakly interacting massive particles (WIMPs) have been the primary candidates for dark matter in the past decades, alternative explanations have gained more and more attention due to a growing number of null-results in experimental WIMP searches. Here, we go beyond the...
Models of feebly-interacting Dark Matter (DM) have gained popularity due to the non-observation of DM in direct detection experiments. Unlike DM freeze-out, which occurs when the dark sector particles are non-relativistic, feebly-interacting DM is primarily produced at temperatures corresponding to the heaviest mass scale involved in the production process. Consequently, incorporating finite...
In this talk I will consider a DM model with a new sector comprising of a Dark Matter fermion and a colored, heavier scalar, Yukawa-coupled to a Standard Model quark. In this model the DM fermion is produced both from freeze in and from the later decays of the frozen-out scalars. I will discuss how thermal effects such as the emergence of collectivity, of screening and of multiple...
The standard approach of calculating the relic density of thermally produced dark matter based on the assumption of kinetic equilibrium is known to fail for forbidden dark matter models since only the high momentum tail of the dark matter phase space distribution function contributes significantly to dark matter annihilations, resulting in early kinetic decoupling of dark matter. Furthermore,...
The invisible decay of cold dark matter into a slightly lighter dark sector particle on cosmological time-scales has been proposed as a solution to the $S_8$ tension. In this talk, I want to present a possible embedding of this scenario within a particle physics framework and discuss its phenomenology. The model is set up of a minimal dark matter decay, where the dark sector contains two...
Gravitational waves provide a new window into the early Universe, and thus a new way of probing the dynamics of dark sectors. I will provide an overview of primordial gravitational wave sources, highlight what we have learned recently and speculate about possible future insights.
Direct experimental evidences of dark matter have been searched exploiting several technologies.
Among these, liquid xenon TPCs have demonstrated extraordinary sensitivity for WIMP dark matter searches.
Moreover, the XENONnT experiment has also recently demonstrated to reach an unprecedented level of WIMP sensitivity and electronic-recoil background, unlocking the possibility of exploring...
One of the most pressing questions for modern physics is the nature of dark matter (DM). Several efforts have been made to model this elusive kind of matter since the largest fraction of DM cannot consist of any of the known particles of the Standard Model (SM) according to the Lambda-CDM model. Among the candidates proposed to explain the nature of DM, weakly interacting massive particles...
The flux of high-energy gamma rays provides crucial information for constraining the properties of particle dark matter candidates, such as Weakly Interacting Massive Particles (WIMPs) or Axion-Like Particles (ALPs). Slowly but steadily entering the construction phase at its sites in both the northern and southern hemispheres, the Cherenkov Telescope Array (CTA) is set out to explore the sky...
In many extensions of the Standard Model, the universe underwent one or several first order phase transitions. Such phase transitions proceed via the formation and collision of bubbles. The bubble collisions can source a stochastic gravitational wave background signal. In the case of the electroweak phase transition, the characteristic frequency would fall right in the sensitivity band of...
Hot viscous plasmas unavoidably emit a gravitational wave background, similar to the electromagnetic black body radiation. We study the contribution from hidden particles to the diffuse background emitted by the primordial plasma in the early universe. While this contribution can easily dominate over that from Standard Model particles, we find that both are capped by a generic upper bound that...
Earlier this year several pulsar timing arrays unveiled the first detection of the stochastic gravitational wave background at nano-Hertz frequencies. The background could potentially arise from myriad merging black holes or – arguably more exciting – an event in the early cosmos. In this talk, I will discuss two recent works on the origin of the new signal: First, I will show under which...
Parton showers are part and parcel of particle phenomenology, but what in the case of a confining dark sector with no light quarks below the confinement scale? The only available hadronic states are dark glueballs, composite dark gluon states. To date, there have been very few quantitative studies of dark shower signatures with dark glueball final states, despite the fact they commonly appear...
Taking axion inflation as an example, we study the evolution of a non-Abelian dark sector coupled to inflaton for different choices of the confinement scale. For confinement scales just a few orders of magnitude below the Planck scale, gravitational wave signal generated by fluctuations in the thermal plasma may become relevant. Another possible source of gravitational waves is the confinement...
We analyze the phase transition in improved holographic QCD and obtain an estimate of the gravitational wave signal emitted in the confinement transition of a pure SU(N) Yang-Mills dark sector.
Since the LIGO-Virgo-KAGRA gravitational wave (GW) detection from binary systems, GWs have become one of the most promising probes of cosmology and fundamental physics. The GW agenda is complemented by Pulsar Timing Arrays (PTA) probing the nHz frequency band, such as the European PTA (EPTA) and NANOGrav, both recently reporting a 3sigma evidence for a GW background. A next major step in that...
Chairs: Marco Drewes, Jorinde van de Vis
Panel Members: Mathias Becker, Maria Pilar Casado, Simona Procacci, Henrique Rubia, Carlo Tasillo
The bubble wall velocity is a critical parameter for estimating the gravitational wave signal coming the phase transitions in the early universe. The most precise computations are usually quite involved and require time, which can make then inconvenient for the large use to BSM models. In this talk, I will present two limits, the local thermal equilibrium limit and the relativistic limit, in...
Theories beyond the Standard Model (BSM) with classical scale invariance predict an intriguing thermal history of the early Universe. Due to the absence of dimensionful terms at tree level in these models, the electroweak phase transition (EWPT) can be significantly delayed, inducing a period of thermal inflation supercooling the Universe. As the SM quarks may remain massless at the QCD scale,...
The past two decades have been characterised by extraordinary accomplishments in the control of matter and light. This has opened up new avenues for atomic, molecular and optical physics including novel tests of physics beyond the Standard Model. The combined use of effective field theories, precision computations and highly accurate experimental data makes spectroscopy a competent and...
Dark matter can be captured in a neutron star and deposits its energy into a star. This dark matter heating effect, however, can be observed only if it dominates over other internal heating effects in neutron stars. In this work, as such an internal heating effect, we examine the frictional heating caused by the creep motion of neutron superfluid vortex lines in the neutron star crust. The...
The scattering of dark matter from stellar constituents leads to gravitational capture, with important observational consequences. In particular, white dwarf heating occurs due to the energy transfer in the dark matter capture and thermalisation processes, and the subsequent annihilation of captured dark matter. Here I will discuss the capture of dark matter, our study investigates a model...
Compact stars due to their enormous gravitational field can accumulate a sizable amount of dark matter in their interior. Depending on its nature, accumulated dark matter may affect the properties of neutron stars in quite different ways. I will give an overview of the impact of dark matter on various observable properties of neutron stars, i.e. the mass-radius relation, tidal deformability,...
In this talk, we present the role of fermions within multi-TeV colored co-annihilation scenarios. The interactions of fermions with dark matter (DM) and co-annihilating particles have the potential to introduce novel decay channels for bound states. However, we emphasize that these same interactions also provide efficient mechanisms for bound state formation (BSF), complementing the...
In this talk, we present the role of fermions within multi-TeV colored co-annihilation scenarios. The interactions of fermions with dark matter (DM) and co-annihilating particles have the potential to introduce novel decay channels for bound states. However, we emphasize that these same interactions also provide efficient mechanisms for bound state formation (BSF), complementing the...
For a quantitative investigation on the time evolution of heavy thermal dark matter at and after thermal freeze-out, near-threshold processes need to be taken into account which have a large impact on the observed dark matter relic abundance. We study the recoil effect of heavy dark matter pairs in a thermal bath and compute the thermal rates of dark matter fermion-antifermion pairs in the...
We make a comprehensive study of vector-like fermionic dark matter and flavor anomalies in a simple extension of standard model. The model is added with doublet vector-like fermions of quark and lepton types, and also a $S_1(\bar{\textbf{3}},\textbf{1},1/3)$ scalar leptoquark. An additional lepton type singlet fermion is included, whose admixture with vector-like lepton doublet plays the role...
If dark matter couples to force mediators that are much lighter than itself, then its interactions manifest as long-ranged. This gives rise to non-perturbative effects, including the existence of bound states. The formation of stable or metastable dark matter bound states can affect the dark matter phenomenology very significantly, including the dark matter relic density, indirect and direct...
In this work, we address the impact of the thermal Debye mass $m_D$ scale on the bound-state formation and ionization (dissociation) in the dark sector in the Early Universe. We focus on heavy dark fermions (with mass $m$) charged under a $U(1)_d$ group coupling dark matter to dark photons and dark light fermions with the coupling constant $\alpha = g^2/4\pi$. We determine the effect of the...
In this talk, my objective is to present the phenomenology of Electroweak multiplets as potential Dark Matter (DM) candidates in the coming years, with a specific focus on detection possibilities at the muon collider. To begin, I will delve into the thermal production mechanism in the early Universe and provide an overview of the current phenomenological landscape concerning the search for...
Dark Matter being electrically neutral does not participate in electromagnetic interactions at leading order. However, we discuss here fermionic dark matter (DM) with permanent magnetic and electric dipole moment that interacts electromagnetically with photons at loop-level through a dimension-5 operator. We discuss the search prospect of the dark matter at the proposed International Linear...
Indirect detection is one of the most powerful methods to search for annihilating dark matter. In this work, we investigate the impact of non-perturbative effects in the indirect detection of dark matter. For this purpose we utilize a minimal model consisting of a fermionic dark matter candidate in the TeV mass range that interacts via scalar- and pseudo-scalar interactions with a massive...
I review how strongly coupled potential nonrelativistic QCD (pNRQCD) and lattice
can describe quarkonium in the confinement region. A new effective field theory called Born Effective Field Theory (BOEFT) is able also to describe the new XYZ exotics discovered in the sector with two heavy quarks. I discuss the implications
of these findings for nonperturbative scenarios of DM.
We present a generalization of the pNRQCD framework to multi-hadron systems, focusing on the regimes of binding for heavy di-quarkonium and di-baryon states in general. Employing advanced Quantum Monte-Carlo methods, we investigate these complex bound states’ binding and implications as potential dark matter candidates. Our methods aim to eventually illuminate their role in the dark matter...
The evidence for dark matter is perhaps of the strongest call for new physics. On top of being desirable from the phenomenological and observational points of views, the possibility of a richer dark sector, that comprises more than one particle, is fairly common in many DM models. The dark particles can enjoy their own hidden forces, which are far less constrained than the interactions...
The formation and decay of metastable dark matter bound states in the early universe can deplete the dark matter abundance, thereby affecting the predicted couplings and mass. The efficacy of the effect is suppressed by the ionisation and excitations of bound states due to the ambient radiation. While existing calculations take into account the thermal radiation, the dynamics of Hydrogen...
We reexamine the consequences of perturbative unitarity on dark matter freeze-out when both Sommerfeld enhancement and bound state formation affect dark matter annihilations. At leading order (LO) the annihilation cross-section is infrared dominated and the connection between the unitarity bound and the upper bound on the dark matter mass depends only on how the different partial waves are...
A UV complete model where the Dark Matter (DM) particle interacts with gluons via a colored scalar mediator provides a viable phenomenological model that can be tested at hadron colliders. While Mono-jet signatures are relevant for Collider searches, zero-jet processes would mean complete annihilation of Standard Model (SM) particles to DM particles, which contribute to relic-density of DM. We...
Heavy dark matter can be created by a first order phase transition and match the observation even for masses much larger than expected by the GK bound on WIMP. In the case of suppressed interactions with the thermal bath the DM might display free-streaming, leading to the possibility of having simultaneously warm and heavy DM. In this talk I extend the previous discussion to the case of...
