axions++ 2023

Session

Astro - HEP Phenomenology

28 sept. 2023, 13:45

Auditorium Vivargent (LAPTh)

41. Axions as Thermal DM: A ChPT Approach

José Antonio Oller (University of Murcia)

28/09/2023 13:45

22. The Chiral Lagrangian for CP-violating Axion-like particles

Gabriele Levati (Università degli studi di Padova and INFN Padova)

28/09/2023 14:15

CP-violating probes are among the most promising and yet relatively unexplored ways to look for Axion-Like Particles (ALPs) and to investigate their phenomenology. With this work we construct the most general effective Chiral Lagrangian describing the interactions of a light CP-violating ALP $\phi$ with mesons, baryons, leptons and photons at energies below the QCD confinement scale ($m_\phi...

27. Axion Dark Matter with Flavor-Violating Couplings to Quarks

Alessandro Dondarini (Pisa University, INFN)

28/09/2023 14:35

We discuss simple scenarios where quark flavor-violating couplings generate the observed dark
matter abundance through freeze-in of an axion-like particle with mass in the few keV range. We show that these
scenarios are constrained by supernovae, structure formation and collider bounds and can be almost entirely probed by future X-ray telescopes.

28. A Visible QCD Axion Portal to GeV-Scale Dark Matter

GIOVANNI ARMANDO (University of Pisa and INFN)

28/09/2023 14:55

We consider a model involving a visible QCD axion with mass in the MeV range with flavour non-universal couplings to the Standard Model (SM) first generation quarks and with all the SM leptons. Such a heavy axion must evade a variety of stringent constraints which precisely fix the couplings to the SM fields. While this heavy axion cannot be a Dark Matter (DM) candidate, as it decays...

40. Axion-mediated Dark Matter beyond freeze-out

Aoife Bharucha (CPT, Marseille)

28/09/2023 15:25

Recent experimental advances further constrain electroweak-scale WIMPs produced via thermal freeze-out, leading to a shift away from this standard paradigm. Here we consider an axion-like particle (ALP), the pseudo-Goldstone boson of an approximate U(1) global symmetry spontaneously broken at a high scale fa, as a mediator between the Standard Model (SM) particles and the dark matter (DM)...

16. Light dark matter and its possible probes

Sreemanti Chakraborti (IPPP Durham)

28/09/2023 15:45

We consider models of light dark matter and light mediator, having mass of the order of a few MeV to a few GeV. In each case, the dark matter achieves relic density through mechanisms beyond the paradigm of typical freeze-in or freeze-out. The light mediators in these models, namely dark scalars, vectors or ALPs, couple to the SM particles. These interactions can be constrained by...

49. Quadratic Coupling of Axions to Photons

Carl Beadle (UNIGE)

28/09/2023 16:05

In a recent work, using chiral perturbation theory as a guide, we showed that the QCD axion couples to the electromagnetic kinetic term at one loop.
If axions make up dark matter, they should then induce some temporal variation of the fine structure constant α, which is severely constrained.
This argument can be generalised to ALPs and can lead to stringent constraints in ALP parameter...

42. Solar Halo of Axions and Implications for Direct Detection

Joshua Eby (Stockholm University)

28/09/2023 16:25

Ultralight dark matter (ULDM) is known to form self-gravitating bound states through relaxation of the field, through gravity or self-interactions. The canonical example is a boson star, which is self-gravitating and has been studied for decades. In this talk, I will discuss a related but distinct bound state we call a gravitational atom, which is bound by the gravitational potential of some...