New directions EXploring the Unknown beyond the Standard Model (NEXUS 2026)

Session

Parallel talks (3A)

13 Sept 2026, 13:10

Tsung-Dao Lee Institute/S5F-S500 - Lecture Room (Tsung-Dao Lee Institute)

1. Specially Embedding a Composite Axion Model

Shihwen Hor (T. D. Lee Institute)

13/09/2026, 13:10

We present a novel framework of the post-inflationary composite axion to address the strong CP problem without the cosmological domain wall problem. Conventional composite axion models lead to the domain wall number greater than one, producing stable axion domain walls that overclose the Universe. We show that by considering a special embedding of the confining gauge group responsible for the...

45. Deconstructing the Extra-Dimensional Axion

Junxuan Xu (TDLI)

13/09/2026, 13:30

We present a four-dimensional deconstruction of the extra-dimensional axion arising from a $U(1)$ gauge theory in a five-dimensional orbifold, where the axion is identified with the Wilson line of the $U(1)$ gauge field and its coupling to QCD is generated by a 5D Chern-Simons (CS) term. We construct the corresponding 4D moose (quiver) gauge theory with link scalar fields, in which the axion...

33. Ultraviolet-Sensitive Axion Potentials from Small Instantons

Saurabh K Shukla (Nankai University)

13/09/2026, 13:50

Oral Presentation

Small instantons can significantly modify the axion potential in KSVZ models containing vector-like quarks (VQs). Using naive dimensional analysis, we analyse models with a single VQ, multiple identical copies, and sets of distinct VQs, while requiring the gauge couplings to remain perturbative up to the Planck scale under two-loop running. Their differing fermion zero-mode structures require...

56. MeV Electrophilic Axion-like Particles production from Sun and its detection

Sk Jeesun - (Tsung Dao Lee Institute)

13/09/2026, 14:10

Oral Presentation

This work explores the production of MeV-scale electrophilic axion-like particles (ALPs) by utilizing the monochromatic 5.5 MeV photon resulting from the nuclear fusion processes in the Sun. These 5.5 MeV photons can undergo Compton-like scattering with the ambient electrons in the solar matter to produce a substantial flux of MeV ALPs. Upon reaching the Earth, such ALPs can be detected via...