Séminaire / Seminar GReCO |
| « Riess et al., rate ratios, and relic radiation » |
|
Lloyd Knox |
| We know that rate ratios play a key role in understanding helium production in the big bang. A particularly important ratio is the per-particle weak interaction rate for interconversion of neutrons and protons relative to the expansion rate. So if you measure how much helium is produced, and you know this weak interaction rate, you can infer the expansion rate during BBN. Our question is: if you measure the CMB map, what are the key rates you need to know so that you can infer H(z), and H(z=0) in particular? Addressing this question leads us to a solution to the Hubble constant problem, although one that runs into a catastrophic problem with, of all things, the helium abundance. |
|
lundi 9 octobre 2023 - 11:00 Amphithéâtre Henri Mineur Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |