Neutrinos, Dark Matter and Dark Energy
The focus of the workshop will be on the physics of the "Invisibles":
Talks are by invitation only, except for PhD students: they are welcome to apply to participate in the PhD forum with a 5 min. plenary talk complemented with a poster on the same subject.
May 1st: Deadline for abstract submission for PhD students for plenary 5 min talk + poster.
April 9th: Deadline for early registration fee
May 10th: Deadline for late registration
The Invisibles19 Workshop is organised in the context of the Horizon 2020 funded projects ELUSIVES (674896-ELUSIVES-H2020-MSCA-ITN-2015) and InvisiblesPlus (690575-InvisiblesPlus-H2020-MSCA-RISE-2015), which focus on Neutrinos, Dark Matter and Dark energy and their connection, with emphasis on the role of the symmetry relating matter and antimatter. It has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Slodowska - Curie grant
agreements No 690575 and Nº 674896.
The IceCube project has transformed a cubic kilometer of natural Antarctic ice into a neutrino detector. The instrument detects more than 100,000 neutrinos per year in the GeV to PeV energy range. Among those, we have isolated a flux of high-energy neutrinos of cosmic origin, with an energy density similar to that of high-energy photons and cosmic rays in the extreme universe. We recently identified their first source: on September 22, 2017, several astronomical telescopes pinpointed a flaring galaxy, powered by an active supermassive black hole, as the source of a cosmic neutrino with an energy of 290 TeV. Archival IceCube data subsequently revealed in 2014 a flare of more than a dozen neutrinos from the same direction. At a distance of four billion light-years, ten times further than the nearest such sources, the first cosmic ray accelerator seems to belong to a special class of active galaxies that may be responsible for the origin of the highest energy particles in the Universe.
The precision of atomic spectroscopy serves as a tool for particle physics and Dark Matter searches. New interactions between the nucleus and the electron mediated by a boson from beyond the Standard Model modify the atomic spectrum. I will present the sensitivity of different experimtal setups, such as King plots of isotope shifts, Rydberg states and dynamical decoupling, to long-range Yukawa interactions, oscillating Dark Matter and the relaxion.
A large experimental program is underway to extend the sensitivity of direct detection experiments, searching for interactions of Dark Matter with nuclei, down to the
neutrino floor. However, such experiments are becoming increasingly difficult and costly due to the large target masses and exquisite background rejection needed for the
necessary improvements in sensitivity. We investigate an alternative approach to the detection of Dark Matter-nucleon interactions: Searching for the persistent traces left
by Dark Matter scattering in ancient minerals obtained from much deeper than current underground laboratories. We estimate the sensitivity of paleo-detectors, which extends
far beyond current upper limits for a wide range of Dark Matter masses.
There has been recent interest in leptogenesis induced by "light" right-handed neutrinos, with masses in the GeV range. Apart from accounting for the observed baryon asymmetry,
this scenario may produce lepton asymmetries much larger than the baryon asymmetry. A possible consequence of the latter could be keV-scale sterile neutrino dark matter production through the resonantly enhanced Shi-Fuller mechanism. Making use of a "complete" theoretical framework, which tracks both helicity states of the right-handed neutrinos as well as their kinetic non-equilibrium, and solving numerically a set of
non-linear evolution equations, we explore to what extent such a minimal scenario could represent a viable explanation for dark matter and baryogenesis.
One of the strongest predictions of the cold dark matter paradigm is the hierarchy of structure down to Earth-mass scales. However, individual self-bound clumps of dark matter--"halos"--are difficult to detect directly. Instead, we use galaxies as lampposts for halos. By counting galaxies, our goal is to measure the underlying population of dark matter halos. In this talk, I describe two results that seem completely at odds with each other in measuring the population of small halos. I argue that the resolution to the problem is a better mapping between galaxies and halos. I will show what my group is doing so far to address the problem, and what opportunities lie ahead in the wide-field surveys of the 2020's.
In my talk I will discuss the dependence of the dark matter production mechanism in the early universe on its coupling to the Standard Model and mediator. For illustration, I will focus on the case of compressed mass spectrum dark matter scenario and show that we can continuously go from freeze-in to freeze-out with an intermediate stage of conversion driven freeze-out. In the latter case, the feeble couplings involve give rise
to the possibility to exploit the macroscopic decay length of charged mediators to study the resulting long-lived-particle signatures at collider. I will discuss the experimental
reach of such searches on the viable portion of the parameter space.
Freeze-in dark matter (DM) production constitutes an appealing mechanism to generate the DM relic density for very weakly coupled DM particles which never achieve thermal equilibrium with the Standard Model (SM). We examine the collider probes of freeze-in DM through the decay of parent particles and highlight the complementarity of ATLAS/CMS and
the planned MATHUSLA detector in probing such freeze-in DM scenarios at the LHC.
We discuss the phenomenology of three-flavour neutrino mass and lepton mixing and present the current status of three-flavour oscillation parameters from a global fit to oscillation data (NuFit-4.0). We highlight the interplay of complementary data sets for the determination of subleading parameters, such as the octant of theta23, the neutrino mass ordering and leptonic CP violation.
In this talk I will give a concise overview over different ideas to explain lepton mixing parameters and neutrino masses. I will also briefly mention possible connections to the quark sector as well as potential imprints of these ideas beyond lepton mixing parameters and neutrino masses in concrete models.
Since the discovery of neutrino oscillations twenty years ago, the field has made rapid progress in measuring the underlying mixing and mass splitting parameters that govern the oscillations. Neutrino oscillations have been observed several modes and the next steps, which involve establishing the pattern of neutrino masses and whether neutrino mixing violates CP symmetry are well underway. I will present the latest status
of these experiments and future prospects.
Light sterile neutrinos with a mass around 1 eV have been studied for many years as a possible explanation of the so called short-baseline neutrino oscillation anomalies. I will review our current knowledge on the light sterile neutrino in the 3+1 model, discussing the status of the most relevant searches at neutrino oscillation experiments and the impact that
the new neutrino would have on cosmology.
We present a model where a low scale dynamical mechanism gives rise to neutrino masses. In this model new light particles, charged under a dark U(1) gauge symmetry, communicate with the Standard Model particles only via mixing: flavour mixing (neutrinos), mass mixing (scalars) and kinetic mixing (a new light mediator). We discuss how this model can provide a possible explanation to MiniBooNE electron-like event excess.
The discovery of double beta decays without neutrinos whould imply the lepton number violation and would change our understanding of the nature of the neutrinos. Currently, there is a long list of experiments that are searching this hypothetical decay. In this presentation, the techniques and results of the current experiments of double beta decay without neutrinos will be reviewed, and the challenges and future perspectives of the next generation experiments presented.
I will review the physics of neutrinos from core collapse
supernovae, with highlights of recent advances in this field. Emphasis will be placed on how to improve the theory of neutrino emission and propagation, and on the physics potential of the next generation ofneutrino detectors. Different regimes will be discussed, ranging from a very high statistics observation of a nearby supernova, to the quasi-diffuse or diffuse flux detection from several very distant collapsing stars. New directions involving multi-messenger observations of supernovae (with neutrinos, photons and gravitational
waves) will be presented.
Current and near future 21cm cosmological surveys promise to offer a wealth of information about state of the Universe during the early stage of reionization and the cosmic dawn, cosmological epochs which have yet to be directly probed. The 21cm signal produced during these epochs is remarkably sensitive to the state of the IGM, and thus can provide a strong probe of any exotic model that modifies either the temperature evolution of the medium or the formation of structure. In
this talk I will focus on the potential signatures arising from a
population of ~ solar mass primordial black holes (PBHs) that account for a subdominant fraction of the dark matter. I will illustrate three distinct effects produced by these PBHs and comment on the expected sensitivity to the 21cm power spectrum from experiments like HERA
(Hydrogen Epoch of Reionization Array) and SKA-Low, showing that 21cm observations may improve existing constraints by multiple orders of magnitude. Should time permit, I will comment on techniques being developed that will allow for a greater weather of information to be extracted from the data, and will greatly ease computational difficulties associated with predicting the 21cm signal at high redshifts.
I will review one of the predictions of the Big Bang theory, the existence of a cosmic neutrino background. I will then present the effect that neutrino masses induce on cosmological observables at linear order. I will show the canonical effect that has been commonly employed on cosmology to weigh neutrinos: their effect on the power spectrum. I will show why we need to consider other observables to achieve a robust
5-sigma constraint on the minimum mass of the neutrino masses with upcoming cosmological surveys.
A review of the physical effects and impacts of several dark matter particle candidates on the observable characteristics of 21-cm emission and absorption from the high-redshift Universe will be presented, including annilation to gamma-rays, energy release from black holes, elastic scattering
with baryons, and dark matter free-streaming effects.
We present the implications for cosmic inflation of the Planck 2018 data release, reviewing the constraints on slow-roll inflationary models, on features in the primordial power spectrum, on isocurvature perturbations. We then discuss the capabilities of future observations to improve some of the current constraints.
I will review the theoretical and observational status of
stochastic gravitational wave (GW) backgrounds as a probe of early Universe cosmology, reviewing the main sources such as inflation, (p)reheating, first order phase transitions, and general topological defects.
Primordial Black Holes (PBHs) are black holes formed in the early Universe, for instance from the collapse of large density perturbations generated by inflation. The discovery of gravitational waves from mergers of ~10 Solar mass black hole binaries has led to increased interest in PBHs as a dark matter candidate. I will review the formation of PBHs and the limits on their abundance, with particular emphasis on microlensing
constraints in the Solar mass region.
We conjecture that there exists a scalar bound state for every pair of fundamental fermions at a UV (composite) scale. This implies a large number of universally coupled, sub-critical Higgs doublets. All but the Standard Model Higgs are dormant, with large positive squared masses and each receives a small vacuum expectation values via mixing with the Standard Model Higgs. Universal couplings, modulo renormalization group running effects, flips the flavor problem into the masses and
mixings of the Higgs system. Doublets associated with heavy fermion masses, b, c, likely lie in the multi-TeV range, but may be observable at the current LHC, or a high-luminosity and/or an energy-upgraded LHC. In the lepton sector we are lead to a
Higgs seesaw for neutrino masses, and corollary processes of observable flavor violation. The observation of the first sequential doublet coupled to bb with masses around 3 TeV
would lend credence to the hypothesis.
Even though the LHC searches so far did not unveil the new physics particles, observations made at the LHC and at the B-factories point towards lepton flavor universality violation in both tree-level and loop-induced B-meson semileptonic decays. After a brief review of the current status of these anomalies, I will discuss general implications that can be derived by using (i) an effective field theory approach and (ii) specific leptoquark models.
In this talk I will review the main ideas for detection of neutral LLPs from accelerator based experiments. The status of searches for heavy neutral leptons at the LHC and fixed
target/beam dump experiments is presented. An outlook of new proposals and their implications for heavy neutral leptons is also discussed.
In this talk I discuss the gravitational wave signals of dynamical axion models. In particular, we focus on models which solve the strong CP problem and include the confinement of a QCD-like gauge group at the TeV scale. I discuss the resulting chiral symmetry breaking phase transition for models with three and four light flavors using the linear sigma model. The amplitude of the gravitational wave spectrum depends on the mass of the
dynamical axion. The resulting spectra may be observed at future mid-range gravitational wave experiments such as AION/MAGIS, DECIGO, and BBO.
Moreover, the TeV states can be searched for at colliders, providing a unique connection between axion physics, gravitational waves and collider searches.
Consistency with quantum gravity can have significant consequences on low energy physics. Interestingly, it seems that not every effective field theory can be consistently coupled to quantum gravity unless it satisfies some additional consistency constraints. In this talk, I will review one of these constraints, dubbed The Weak Gravity Conjecture, with special focus on its phenomenological consequences for Particle Physics. In particular, we show that a refinement of this conjecture, when applied to compactifications of the
Standard Model, implies an upper bound for the neutrino masses in terms of the cosmological constant in our universe. Furthermore, Majorana neutrinos would only be compatible if accompanied by very light new BSM physics.
This bound can also be translated into an upper bound for the EW scale around the TeV range, bringing a new perspective into the EW hierarchy problem.
Today's searches for dark matter suggest that it might interact only very weakly with the particles we observe. This insight changes our picture of how the dark matter abundance was created in the early universe. In this talk, we will test this
picture at the LHC. In a scenario with tiny couplings to the Higgs boson, I will show that dark matter is produced from long-lived particles that leave peculiar signatures in the LHC detectors. Their discovery can tell us more about the origin of the observed dark matter abundance.
Despite the abundance of Higgs measurements and the apparent compatibility of the data with the Standard Model, there remains crucial questions aboutthe electroweak symmetry breaking sector. The most pressing question is whether the Standard Model is a low energy limit of some high scale UVcomplete model, leading to a spectrum of Higgs bosons and small variations from Standard Model predictions. I will discuss approaches to answering this question in the absence of the experimental observation of new resonances.
Using recent results from the global fitting framework GAMBIT, I review the plausibility of the simplest thermal dark matter models in light of the latest observations. I will show results for the following models that feature popular dark matter candidates. The Standard Model of elementary particles (SM) augmented with a real spin zero, a Majorana fermion, or a vector boson gauge singlet particle coupling via the Higgs portal. The QCD axion, the KSVZ and DFSZ axion models and general axion-like particles. The Constrained Minimal Supersymmetric SM (MSSM), the Non-Universal Higgs Mass model (versions 1 and 2), a 4-dimensional MSSM with light electroweakinos, and the 7-dimensional MSSM.
We will described the particle physics and astrophysics motivations for an ultra-light axion as a dark matter candidate. Its rich phenomenology, including some recent developments, will be discussed.
he high energy frontier at the LHC may provide an answer to the question of neutrino mass origin. A paradigmatic example is the Left-Right symmetric theory with heavy Majorana neutrinos. We review the existing status of collider searches for lepton number violating signals at the LHC. In order to fully realize the potential coverage for such particles, both prompt and displaced signals ought to be considered. These arise either from the extended gauge sector or from additional scalars that may mix with the Higgs and lead to exotic, potentially displaced, lepton number violating decays. These offer a direct insight to spontaneous mass origin of neutrinos, in complete analogy to the SM fermions.