Conveners
Afternoon Session: Session 1
- Aqeel Ahmed (Max-Planck-Institut fรผr Kernphysik, Heidelberg)
Afternoon Session: Session 1
- Jan Pawlowski (ITP, Heidelberg)
Afternoon Session: Session 2
- Evgeny Akhmedov (Max-Planck-Institut fuer Kernphysik, Heidelberg, Germany)
Afternoon Session: Session 1
- Matthias Neubert
Afternoon Session: Panel Discussion on New Physics Directions in the LHC era and beyond (Panelists: Tao Han, Gudrun Hiller, Mariano Quiros, James Wells)
- Florian Goertz (Max-Planck-Institut fuer Kernphysik, Heidelberg, Germany)
Afternoon Session: Poster Session
- There are no conveners in this block
Novel bounds on CP-odd fermionic couplings of ALPs (axion-like-particles) and of a general singlet scalar are presented and compared. In both cases, we improve present constraints by several orders of magnitude. The impact of an additional Peccei-Quinn symmetry will be discussed as well.
The individual fermion generations of the Standard Model fit neatly into a representation of a simple Grand Unified Theory gauge algebra. If there is nothing to Grand Unification, this would be appear to be a coincidence. We attempt to quantify how frequent this coincidence is among theories with group structure and fermion content similar to the Standard Model. This bottom-up theory-space...
We assess the complementarity between colliders, direct detection searches, and gravitational wave interferometry in probing a scenario of dark matter in the early universe. The model under consideration contains a $B-L$ gauge symmetry and a vector-like fermion which acts as the dark matter candidate. The fermion induces significant a large dark matter-nucleon scattering rate, and the...
We present a model which addresses two open questions of the Standard Model (SM): the origin of neutrino masses and the nature of dark matter. To achieve this, the SM is extended by two keV-mass right-handed neutrinos as well as a Froggatt-Nielsen-like mechanism, under which only the non-SM fields are charged.
The sterile neutrinos form a 2-component dark matter candidate. We assume the...
We propose a comprehensive study of the Direct Detection phenomenology of singlet Dark Matter t-channel portal models. For that purpose, we present a complete computation of the loop induced direct detection cross-section for both scalar and fermionic Dark Matter candidates. We complete the study by comparing the results with current and future bounds from Direct Detection experiments and...
This study investigates the sensitivity of the Cherenkov Telescope Array (CTA) and Fermi Large Area Telescope (Fermi-LAT) to dark matter (DM) annihilation in ฮณ-ray lines. We focus on observations of the Galactic Center (GC), dwarf Spheroidal galaxies (dSphs), and galaxy clusters (GCls). Specifically, we compare the reach of the GC with that of dSphs, considering the poorly known putative core...
Exotic decays with high multiplicity lepton final states are important indicators of SM interactions with dark sectors and have low observational backgrounds at the LHC. In order to explore hidden valleys/dark sectors (HV/DS), we have recast a recent ATLAS study searching for least two pairs of leptons with equal invariant mass: hep-ex/2306.07413. We have reproduced the results of this study,...
Diffuse neutrinos from past supernovae in the Universe present us with a unique opportunity to test dark matter (DM) interactions. These neutrinos can scatter and boost the DM particles in the Milky Way halo to relativistic energies allowing us to detect them in terrestrial laboratories.
Focusing on generic models of DM-neutrino and electron interactions, mediated by a vector or a scalar...
We apply the criterion of finite naturalness to the limiting case of a generic heavy sector decoupled from the standard model. The sole and inevitable exception is represented by gravitational interactions. We demonstrate how gravity can couple the Higgs to the heavy scale well before the three-loop diagrams mediated by the top quark discussed in previous literature. As an application, we...
In models with spontaneous symmetry breaking by scalar fields in large group representations, we observe that some of the scalar masses can be loop-suppressed with respect to the naive expectation from symmetry selection rules. We present the most minimal model โ the SU(2) five-plet โ with such accidentally light scalars, featuring compact tree-level flat directions lifted by radiative...
I break the U(1)$_\text{EM}$ of the standard model by introducing new general scalar fields that obtain vacuum expectation values in their non-neutral components.
This is realised with either minicharged particles or with scalars that allow for new renormalisable interactions, which I will illustrate at the example of fermion-fermion-photon interactions.
Finally, I show how...
We employ first principles to quantize field theories living on a bubble wall background in the planar limit, focusing on spontaneous gauge symmetry breaking. Utilizing these principles, we compute the average momentum transfer resulting from transition radiationโsoft emissions during the traversal of an energetic particle across the wall, particularly focusing on longitudinal polarization....
Electroweak Baryogenesis (EWBG) is a very promising avenue to generate the observed Baryon Asymmetry in the Universe (BAU). Making use of elektroweak sphalerons as a baryon number violating process, one seeks to enhance the EW phase transition to be strongly first order and introduce more CP violation. Oftentimes, this is achieved by minimally extending the Standard Model (SM) with an...
We study a non-thermal realization of leptogenesis from the decays of sterile right-handed neutrinos (RHNs) produced via runaway bubble collisions at a generic first order phase transition. We explore the parameter space opened up by this new mechanism, which can accommodate RHN masses of several orders of magnitude heavier than the scale of the phase transition, while avoiding strong washout...
We present an analysis of the first-order supercooled phase transition associated with symmetry breaking in the early Universe in a classically scale-invariant model. We analyze the role of higher order thermal corrections for these transitions, and to what extent they can be computed using dimensionally reduced effective field theory (3D EFT). This framework requires high temperature (HT)...
Different thermal resummation techniques impact the gravitational wave (GW) spectra from cosmological first-order phase transitions predicted in a given particle physics model. To investigate this effect, we perform the first large-scale parameter scan of the electroweak phase transition (EWPT) in the dynamical real-singlet extension of the Standard Model (SM) using three different...
I demonstrate the possibility to perform a parametrically improved search for gauged baryon ($B$) and baryon minus lepton ($B-L$) Dark Photon Dark Matter (DPDM) using auxiliary channel data from LISA Pathfinder. In particular I point out the use of the measurement of the differential movement between the test masses (TMs) and the space craft (SC) which is nearly as sensitive as the tracking...
We introduce a novel approach to investigate sectors solely gravitationally coupled, characterized by significant anisotropies. These anisotropies undergo damping through gravitational interactions with the baryon-photon fluid, inducing heating in the process. The resultant injected heat leads to observable distortions in the cosmic microwave background spectrum. We provide analytic estimates...
The Froggatt-Nielsen (FN) mechanism is one of the oldest and simplest attempts at explaining the striking hierarchies observed in the fermion masses and mixings. Given that FN models give rise to the correct fermion masses and mixings by construction and that the new particles predicted by the models are typically assumed to be heavy, it is not clear if the models are experimentally...
In several models of extended Higgs sectors discrete symmetries play an important role. For instance, in order to avoid flavor changing neutral currents, a discrete Z2 symmetry is imposed on Two-Higgs-Doublet-Models. This can lead to the formation of domain walls as the Z2 symmetry gets spontaneously broken during electroweak symmetry breaking in the early universe. In this case, where the...
The Standard Model Effective Field Theory (SMEFT) stands as a crucial tool in exploring physics beyond the Standard Model. As New Physics (NP) signals remain elusive, there is a growing importance to derive constraints on SMEFT Wilson coefficients. This investigation confronts the complexity arising from a high number of parameter space directions to be constrained, making global analyses...
In this talk I will focus on the study of the leptonic $B^- โ \ell^- \bar{\nu}_\ell$ at next-to-leading order in QED. The future improvements of experimental measurements of this channel require a reliable theory prediction, hence a careful theoretical estimate of QED corrections. The multi-scale character of this process requires an appropriate effective theory (EFT) construction to...
$\mathcal{Z}_{\rm N} \times \mathcal{Z}_{\rm M}$ flavour symmetry presents a novel discrete symmetry based framework that effectively address the flavour problem of the Standard Model. Employing current as well as future projected sensitivities of the quark and leptonic flavour observables, the flavour phenomenology of the two different realizations of this framework, including the minimal...
The observation of a lepton-number violating (LNV) process would have far-reaching consequences for our understanding of fundamental physics. It would have implications on the viability of leptogenesis scenarios, and point toward a Majorana nature of neutrinos. In this talk, we will point out the possibility of searching for a hint of LNV in the rare meson decays $K\to\pi+$ invisible and...
We propose a model that can solve simultaneously the doublet-triplet splitting problem of grand unified theories, the electroweak hierarchy problem and the strong CP problem. The mechanism is based on the dynamics of two light scalars that can crunch the universe at the QCD phase transition if triplets are light or if the doublets are heavy or do not have a vev. The same mechanism was...
I will discuss a simple unified formalism for GW detectors that captures the sensitivity of widely different apparatuses (PTAs, LIGO, Weber bars, cavities and more). This allows to estimate the ultimate reach on GWs from a specific detector and to identify the best detection strategies for particular frequency intervals. Interestingly, a few existing detector proposals violate our simple...
UV/IR Mixing is an umbrella term for phenomena in which high and low energy physics does not decouple as expected, for example as a consequence of the fact that QFT does not respect holographic scaling.
Based on how UV/IR mixing has been employed in the Cohen-Kaplan-Nelson (CKN) bound and advocated as a solution to the cosmological constant problem, we explore possible consequences of UV/IR...
Models with additional scalars pose interesting new physics scenarios. Apart from additional matter content, such models can also provide solutions to other open problems of the SM, as e.g. vacuum stability or dark matter. I discuss various new physics scenarios, their current constraints as well as discovery potential at current and future colliders.
Spin correlations have been studied in detail for top quarks at the LHC, but have not yet been explored for the other flavors of quarks. Utilizing the partial preservation of the quark spin information in baryons in the jet produced by the quark, we present possible analysis strategies for ATLAS and CMS to measure the spin correlations in $b\bar b$ and $c\bar c$ samples. We find that some...
Differential top-quark distributions are in strong disagreement with their Standard Model predictions. I discuss a model that can explain these tensions with new Higgses whose masses are in agreement with the hints for narrow resonances at 95GeV and 152GeV,
Sterile neutrinos are well-motivated and simple dark matter (DM) candidates. However, sterile neutrino DM produced through oscillations by the Dodelson-Widrow mechanism is excluded by current X-ray observations and bounds from structure formation. One minimal extension, that preserves the attractive features of this scenario, is self-interactions among sterile neutrinos. In this work, we...
We construct an effective field theory for non-relativistic heavy dark matter of arbitrary spin based on the Little group formalism. We present the most general HDMEFT basis up to dimension seven and show that it reproduces the non-relativistic spin 1/2 case presented in the literature. We also discuss the matching onto the relativistic DM EFT.
Nontopological solitons with large global charges and masses, even above the Planck scale, can form in the early universe and dominate the dark matter abundance. In solitosynthesis, solitons prefer to grow as large as possible under equilibrium dynamics when an initial global charge asymmetry is present. Their abundance is set by when soliton formation via particle fusion freezes out, and...
In this talk, we will explore the phenomenological implications for axion dark matter production via misalignment during inflationary reheating. We investigate scenarios involving inflaton oscillating in a generic potential $\sim \phi^n$, considering inflaton decay and annihilation for reheating. For low reheating temperatures, the parameter space leading to the correct relic abundance can...
The early Universe represents a unique laboratory for frontier physics, providing extreme conditions and amazing chances to test theoretical models. A large class of cosmological phenomena may allow us to probe particle physics at energy scales much beyond the reach of current and future colliders. Within this class, first order phase transitions cover a privileged role since they may leave...
