Phenomenology 2022 Symposium: From Virtual to Real

Session

Axion

9 May 2022, 14:15

Lawrence Hall 106

Conveners

Axion

• Gustavo Marques Tavares (University of Maryland College Park)

152. Axion dark matter-induced echo of supernova remnants

Yitian Sun

09/05/2022, 14:15

Axions and axion-like particles (ALPs) are a theoretically promising dark matter candidate. In the presence of radio emissions from bright astrophysical sources, nonrelativistic ALPs can undergo stimulated decay to two nearly back-to-back photons, giving bright radio sources counterimages ("echoes") in nearly the exact opposite spatial direction. These echoes are spectrally distinct, and...

8. Polarization Signals of Axions at Magnetic White Dwarfs

Chris Dessert

09/05/2022, 14:30

I will discuss a novel search for axions using observations of magnetic white dwarfs (MWDs). Photons produced as thermal radiation at the MWD surface may convert into an axion as they traverse the magnetosphere, but only if they are polarized parallel to the MWD magnetic field. This introduces a linear polarization in MWD optical spectra that points perpendicular to the MWD magnetic field. I...

75. Axion mass from magnetic monopole loops

Katherine Fraser (Harvard University)

09/05/2022, 14:45

We show that axions interacting with abelian gauge fields obtain a potential from loops of magnetic monopoles. This is a consequence of the Witten effect: the axion field causes the monopoles to acquire an electric charge and alters their energy spectrum. The axion potential can also be understood as a type of instanton effect due to a Euclidean monopole worldline winding around its dyon...

66. Underdamped Axionic Blue Isocurvature Perturbations

SAI CHAITANYA TADEPALLI

09/05/2022, 15:00

Previous computations of strongly blue tilted axionic isocurvature spectra were computed in the parametric region in which the lightest time-dependent mass is smaller than the Hubble expansion rate during inflation, leading to an overdamped time evolution. Here, we present the strongly blue tilted axionic isocurvature spectrum in an underdamped time evolution parametric regime. Somewhat...

56. Altered Axion Abundance from a Dynamical Peccei-Quinn Scale

Itamar J. Allali

09/05/2022, 15:15

I will discuss a model in which the relic abundance of axions is altered from the standard misalignment mechanism, either increased or decreased, due to the presence of a new light scalar that couples to the radial part of the Peccei-Quinn (PQ) field. The light scalar makes the effective PQ symmetry-breaking scale dynamical, altering the early-time dynamics for the axion and affecting its...

10. Electroweak ALP Searches at a Muon Collider

Yunjia Bao (Brown University)

09/05/2022, 15:30

A high-energy muon collider with center-of-mass energy around and above 10 TeV is also a vector boson fusion (VBF) machine, due to the significant virtual electroweak (EW) gauge boson content of high-energy muon beams. This feature, together with the clean environment, makes it an ideal collider to search for TeV-scale axion-like particles (ALP) coupling to Standard Model EW gauge bosons,...

120. Heavy QCD Axions at the LHC and Neutrino Experiments

Soubhik Kumar (UC Berkeley)

09/05/2022, 15:45

Heavy QCD axions with masses O(GeV) and decay constants O(1-100 TeV) can solve the Strong CP and the Axion Quality Problem. They also represent an interesting target for various terrestrial searches. In this talk, I will discuss two new approaches in searching for such axions: (a) a trigger-level analysis to look for low-mass diphoton resonances at the LHC; and (b) looking for fermionic final...