Simulation of Yb:YAG thin-disk lasers with stable resonators and with one or two transverse modes

Supernova constraints on an axion-photon-dark photon interaction

Journal of High Energy Physics ◽

10.1007/jhep06(2021)167 ◽

2021 ◽

Vol 2021 (6) ◽

Author(s):

Anson Hook ◽

Gustavo Marques-Tavares ◽

Clayton Ristow

Keyword(s):

Longitudinal Mode ◽

Transverse Mode ◽

The Other ◽

Unusual Feature ◽

Dark Sector ◽

Longitudinal Modes ◽

Dark Photon ◽

Transverse Modes ◽

Weakly Coupled ◽

Photon Coupling

Abstract We present the supernova constraints on an axion-photon-dark photon coupling, which can be the leading coupling to dark sector models and can also lead to dramatic changes to axion cosmology. We show that the supernova bound on this coupling has two unusual features. One occurs because the scattering that leads to the trapping regime converts axions and dark photons into each other. Thus, if one of the two new particles is sufficiently massive, both production and scattering become suppressed and the bounds from bulk emission and trapped (area) emission both weaken exponentially and do not intersection The other unusual feature occurs because for light dark photons, longitudinal modes couple more weakly than transverse modes do. Since the longitudinal mode is more weakly coupled, it can still cause excessive cooling even if the transverse mode is trapped. Thus, the supernova constraints for massive dark photons look like two independent supernova bounds super-imposed on top of each other.

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Numerical and Experimental Analysis of Yb:YAG Thin Disk Regenerative Amplifier

IEEE Photonics Journal ◽

10.1109/jphot.2021.3080708 ◽

2021 ◽

pp. 1-1

Author(s):

Di Sun ◽

Jie Guo ◽

Wei Wang ◽

Xiao Du ◽

Yongxi Gao ◽

...

Keyword(s):

Experimental Analysis ◽

Thin Disk ◽

Regenerative Amplifier

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Kinematics of Disk Stars in the Solar Neighbourhood

Highlights of Astronomy ◽

10.1017/s1539299600022310 ◽

1998 ◽

Vol 11 (1) ◽

pp. 574-574

Author(s):

A.E. Gómez ◽

S. Grenier ◽

S. Udry ◽

M. Haywood ◽

V. Sabas ◽

...

Keyword(s):

Dispersion Relation ◽

Radial Velocity ◽

Velocity Dispersion ◽

Tangential Velocity ◽

Thin Disk ◽

The Other ◽

Proper Motions ◽

Velocity Data ◽

Kinematic Data ◽

Radial Velocity Data

Using Hipparcos parallaxes and proper motions together with radial velocity data and individual ages estimated from isochones, the velocity ellipsoid has been determined as a function of age. On the basis of the available kinematic data two different samples were considered: a first one (7789 stars) for which only tangential velocities were calculated and a second one containing 3104 stars with available U, V and W velocity components and total velocities ≤ 65 km.s-1. The main conclusions are: -Mixing is not complete at about 0.8-1 Gyr. -The shape of the velocity ellipsoid changes with time getting rounder from σu/σv/σ-w = 1/0.63/0.42 ± 0.04 at about 1 Gyr to1/0.7/0.62 ±0.04 at 4-5 Gyr. -The age-velocity-dispersion relation (from the sample with kinematical selection) rises to a maximum, thereafter remaining roughly constant; there is no dynamically significant evolution of the disk after about 4-5 Gyr. -Among the stars with solar metallicities and log(age) > 9.8 two groups are identified: one has typical thin disk characteristics, the other is older than 10 Gyr and lags the LSR at about 40 km.s-1 . -The variation of the tangential velocity with age(without selection on the tangential velocity) shows a discontinuity at about 10 Gyr, which may be attributed to stars typically of the thick disk populations for ages > 10 Gyr.

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