Conveners
Parallel Session A: Dark Matter
- Michael Schmidt (UNSW Sydney)
Parallel Session A: Neutrino Physics
- Sudip Jana (Max-Planck-Institut für Kernphysik)
Parallel Session A: Dark Matter
- Felix Kling (DESY)
Parallel Session A: Dark Matter
- Aqeel Ahmed (Max-Planck-Institut für Kernphysik, Heidelberg)
Parallel Session A: Dark Matter
- Asher Berlin (NYU)
Parallel Session A: Neutrino Physics
- Amir Khan (MPIK, Heidelberg)
Parallel Session A: Dark Matter
- Giorgio Arcadi
Sub-GeV thermal relic dark matter typically requires the existence of a light mediator particle. We introduce the light two-Higgs-doublet portal, illustrated by a minimal UV-complete model for sub-GeV DM with kinematically forbidden annihilations into leptons.
All new physics states in this scenario lie at or below the electroweak scale, affecting Higgs physics, the muon anomalous magnetic...
Multipartite dark matter (DM) frameworks offer interesting phenomenology like co-annihilation, semi-annihilations, DM conversions etc to address correct relic density but avoid stringent direct search limits. We explore possible signatures of multiparticle DMs at collider via distorted missing energy, missing transverse momentum, missing mass distributions in leptonic signals and discuss...
We study the relic abundance of stable particles from a generic dark sector in the presence and absence of initial dark asymmetries, and our results show that abundances are expected to be of similar magnitude, i.e. multi-component dark matter is quite natural. We first discuss the different possibilities for stabilizing multi-component dark matter and then analyze the final relic abundances...
We explore a new class of simplified extensions to the Standard Model containing a complex singlet scalar as a dark matter candidate accompanied by a vector-like lepton as a mediator, both charged under a Z3 symmetry. In its simplest form, the new physics couples only to right-handed electrons, and the model is able to accommodate the correct dark matter relic abundance around the...
Hidden U(1) symmetries in the right-handed neutrino ($\nu_R$) sector are theoretically well-motivated and would give rise to an inherently dark gauge boson which we refer to as the $\nu_R$-philic $Z'$. An important feature of this $Z'$ is that its couplings to neutrinos are generally much larger than its couplings to charged leptons and quarks, providing a particularly interesting scenario for...
Neutrino oscillations in matter offer a novel path to investigate new physics. The most recent data from the two long-baseline accelerator experiments, NO$\nu$A and T2K, show discrepancy in the standard 3-flavor scenario. Along the same line of discussion, we intend to explore the next generation of long-baseline experiments: T2HK and DUNE. We investigate the sensitivities of relevant NSI...
The latest data of the two long-baseline accelerator experiments NOνA and T2K, interpreted in the standard 3-flavor scenario, display a discrepancy. A mismatch in the determination of the standard CP-phase $\delta_{\rm CP}$ extracted by the two experiments is evident in the normal neutrino mass ordering. While NOνA prefers values close to $\delta_{\rm CP} ∼ 0.8\pi$, T2K identifies values of...
The upcoming campaign of cosmogenic neutrino measurements provides us not only a way to understand the cosmic ray accelerators but also a promising portal to study fundamental particle physics. The future observation of cosmogenic neutrinos is guaranteed given the unprecedented sensitivity of many experimental programs. In this talk, I summarize the new physics potential of those facilities,...
Cosmological relaxation of the electroweak scale provides an elegant solution to the Higgs mass hierarchy problem. In the simplest model, the Higgs mass is scanned during inflation by another scalar field, the relaxion, whose slow-roll dynamics selects a naturally small Higgs vev. In this work we investigate the mechanism in a less conventional regime where the relaxion is subject to large...
In this talk, I will discuss elastic scattering processes between nucleons and the QCD axion dark matter. I point out that the cross section can be enhanced by more than $\mathcal{O}(10^{25})$ by the coherent effect, compared to classical processes.In addition, one may expect stimulated emission effects can also enhance the cross section because the number density of the axion DM is very...
Belle has unique reach for a broad class of models that postulate the existence of dark matter particles with MeV—GeV masses. This talk presents recent world-leading physics results from Belle II searches for dark Higgstrahlung and invisible Z′ decays; as well as the near-term prospects for other dark-sector searches.
The DMRadio suite of experiments seeks to search for one of the most promising Dark Matter (DM) candidates, the axion, via an optimized resonant lumped element search. In order to cover as wide of a parameter space as possible, each of the DMRadio experiments is designed to cover specific complementary mass regions starting from 5 kHz ($\approx$ 20 peV) in the DMRadio-50L experimental all the...
A sterile neutrino with a keV-scale mass is a compelling dark matter candidate. We propose a new production mechanism involving the decay and annihilation of a complex scalar singlet with a Higgs portal coupling which develops a vacuum expectation value. The interactions of the resulting pseudo Nambu-Goldstone boson may thermalise the dark sector. We determine the region of parameter space...
I will illustrate the complementary constraints in a 2HDM model, augmented with a U(1) symmetry, featuring right-handed neutrino Dark Matter and considering different production mechanims both in standard and non standard cosmological scenarios.
Sterile neutrinos with keV-scale masses are popular candidates for warm dark matter. In the most straightforward case, they are produced via oscillations with active neutrinos. Our focus is on mixing with electron neutrinos, which is subject to constraints from several upcoming or running experiments like TRISTAN, ECHo, and HUNTER. We introduce effective self-interactions of active neutrinos...
We propose a new production mechanism for keV sterile neutrino dark matter which does not rely on the oscillations between sterile and active neutrinos nor on the decay of additional heavier particles, and works without employing any new interactions for the sterile neutrinos beyond the standard Yukawa couplings. The dark matter neutrinos are instead produced out of thermal freeze-out, much...
Gravitational force can be obtained by gauging the Poincaré group.
The resulting theory is known as Einstein-Cartan (-Sciama-Kibble) gravity. In the absence of matter, it is indistinguishable from general relativity. The situation changes when matter is considered. In this talk, I will discuss the Einstein-Cartan theory and a novel mechanism for producing singlet fermions in the early Universe.
The Galactic center excess (GCE) remains one of the most intriguing discoveries from the Fermi Large Area Telescope (LAT) observations. I will revisit the characteristics of the GCE by first showing a new set of high-resolution galactic diffuse gamma-ray emission templates. This diffuse emission, which accounts for the bulk of the observed gamma rays, is ultimately due to cosmic-ray...
Spinning black holes (BHs) can efficiently transfer energy to the surrounding environment via superradiance. In particular, when the Compton length of a particle is comparable to the gravitational radius of a BH, the particle's occupation number can be exponentially amplified. In this talk, I will discuss the effect of the primordial-black-hole (PBH) superradiant instabilities on the...
The nature of dark matter, one of the major components of the cosmic standard model, remains one of the outstanding problems in physics. One interesting model is scalar field dark matter (SFDM), which fits naturally into observations in both particle physics and cosmology. Simulations and calculations using SFDM often use a classical field approximation (MFT) of the underlying quantum field...
The detection of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) opens up new opportunities for neutrino physics within and beyond the standard model. Following the initial discovery at a spallation source in 2017, several experimental attempts are currently striving to detect it with a broad variety of modern detection technologies at reactor-site. As a leading reactor experiment,...
Coherent elastic neutrino nucleus scattering (CEvNS) is a well-predicted Standard Model process only recently observed for the first time. Its precise study could reveal non-standard neutrino properties and open a window to search for physics beyond the Standard Model.
NUCLEUS is a CEvNS experiment conceived for the detection of neutrinos from nuclear reactors with unprecedented precision...
Non-standard neutrino interactions with a massive boson can produce the bosons in the core of core-collapse supernovae (SNe). After the emission of the bosons from the SN core, their subsequent decays into neutrinos can modify the SN neutrino flux. We show future observations of neutrinos in a next galactic SN in Super-Kamiokande (SK) and Hyper-Kamiokande (HK) can probe flavor-universal...
We present a generic structure (the layer structure) for decoherence effects in neutrino oscillations by combining the concept of the open quantum system and quantum field theory, which includes and parameterize decoherence effects from quantum mechanical and classical uncertainties. With the help of the layer structure, we classify the former as state decoherence (SD) and the latter phase...
A core-collapse supernova (SN) offers an excellent astrophysical laboratory to test non-zero neutrino magnetic moments. In particular, the neutronization burst phase, which lasts for few tens of milliseconds post-bounce, is dominated by electron neutrinos and can offer exceptional discovery potential for transition magnetic moments. We simulate the neutrino spectra from the burst phase in...
Due to neutrino-neutrino forward scattering, the neutrino flavor conversion inside a supernova is still an open question. This type of interaction leads to a non-linear evolution of neutrino states and is strongly dependent on their angular distribution. Thus, the peculiarities of the supernovae's innermost environment impose a number of complexities on an accurate calculation of the neutrino...
We study the freeze-in of gravitationally interacting dark matter in extra-dimensions. Focusing on a minimal dark matter candidate that only interacts with the SM via gravity a five dimensional model we find that a large range of dark matter and Kaluza-Klein graviton masses can lead to the observed relic density. The preferred values of the masses and the strength of the interaction make this...
If the mediator of a $t$-channel process is allowed to be on its mass-shell, the matrix element becomes singular, leading to infinite cross section. In the case of a stable, massive mediator neither IR-regularization methods nor decay width can be used to regularize the divergence.
This issue has not been extensively discussed in the existing literature, even though it affects processes...
In this talk I will discuss the influence of non-perturbative effects,
namely Sommerfeld enhancement and bound state formation, on the cosmological production of non-thermal dark matter (DM). For this purpose, I will focus on a class of simplified models with t-channel mediators. These naturally combine the requirements for large corrections in the early Universe, i.e. beyond the Standard...
The increasing need of numerical predictions for dark matter models is not always easy to satisfy looking at the software available today. With this work, we present a C++ code to compute 2 to 2 squared scattering amplitudes using MARTY. The numerical library generated in this way has been enriched with additional features, aiming at allowing the user to easily include and use such a...
The enhancement of the spectrum of primordial comoving curvature perturbation R can induce the production of primordial black holes (PBH) which could account for part of present day dark matter. As an example of the effects of the modification of gravity on the production of PBHs, we investigate the effects on the spectrum of R produced by the modification of gravity in the case of...
