23–25 Jan 2023
University of Pisa
Europe/Rome timezone

Axion Free-kick Misalignment Mechanism

25 Jan 2023, 10:20
25m
Aula Magna 'Fratelli Pontecorvo' (University of Pisa)

Aula Magna 'Fratelli Pontecorvo'

University of Pisa

Polo Fibonacci Building E Largo B. Pontecorvo 3 56127 Pisa
Talk

Speaker

Lingxiao Xu (Istituto Nazionale di Fisica Nucleare)

Description

We propose an alternative scenario of axion misalignment mechanism based on nontrivial interplay between axion and a light dilaton in the early universe. Dark matter abundance is still sourced by the initial misalignment of axion field, whose motion along the potential kicks the dilaton field away from its minimum, and dilaton starts to oscillate later with a delayed onset time for oscillation and a relatively large misalignment value due to kick, eventually the dilaton dominates over axion in their energy densities and dilaton is identified as dark matter. The kick effect due to axion motion is the most significant if the initial field value of dilaton is near its minimum, therefore we call this scenario axion “free-kick” misalignment mechanism, where axion plays the role similar to a football player. Dark matter abundance can be obtained with a lower axion decay constant compared to the conventional misalignment mechanism.

Faculty position

postdoc

Topic Field Particle Physics

Primary authors

Lingxiao Xu (Istituto Nazionale di Fisica Nucleare) Seokhoon Yun

Presentation materials