Particle Physics Seminars at BNL

A New Symmetry of Cosmological Observables and a High Hubble Constant as an Indicator of a Mirror World Dark Sector

by Prof. Lloyd Knox (University of California Davis)

US/Eastern
https://bnl.zoomgov.com/j/16027404438?pwd=cWdaZitqL0tjaHFpL1BaVm91cjI5Zz09
Description

Finding cosmological models that are consistent with a wide range of observations, including those that indicate a high Hubble constant (the current rate of expansion of space), has proved to be very challenging. In this talk I explore why. Our exploration leads us to fundamental sources of length scales in cosmological models: gravitational collapse time scales and photon electron-scattering mean free paths. We find that scaling down these quantities leaves cosmic microwave background maps, and many other cosmological observables, nearly invariant, while boosting up the expansion rate. I then introduce a model that takes advantage of this symmetry to boost up model predictions of the Hubble constant given other cosmological data. Gravitational collapse time scales are scaled down from standard cosmological values by a `mirror world' dark sector and photon mean free paths are scaled down by reducing the amount of helium, thereby freeing up more electrons. I speculate about alternative ways to reduce photon mean free paths, as consistency with the Riess et al. (2021) measurement of the Hubble constant requires there to be less helium in the universe than is observed. 
 

Join ZoomGov Meeting
https://bnl.zoomgov.com/j/16027404438?pwd=cWdaZitqL0tjaHFpL1BaVm91cjI5Zz09

Meeting ID: 160 2740 4438
Passcode: 004500
One tap mobile
+16692545252,,16027404438#,,,,*004500# US (San Jose)
+16468287666,,16027404438#,,,,*004500# US (New York)

Dial by your location
        +1 669 254 5252 US (San Jose)
        +1 646 828 7666 US (New York)
        +1 551 285 1373 US
        +1 669 216 1590 US (San Jose)
Meeting ID: 160 2740 4438
Passcode: 004500
Find your local number: https://bnl.zoomgov.com/u/ae0NkactZ

Join by SIP
16027404438@sip.zoomgov.com

Join by H.323
161.199.138.10 (US West)
161.199.136.10 (US East)
Meeting ID: 160 2740 4438
Passcode: 004500

 

Organized by

Sreevarsha Sreejith