Reminder - High Energy Physics SeminarTODAY (Racco)

[HECAP - Margherita Di Giovannantonio]

*_HIGH ENERGY PHYSICS SEMINARS_**__*



*Thursday, 09 May* 2024, at *16:00*  - *LUIGI STASI SEMINAR ROOM - 
https://indico.ictp.it/event/10697//
<https://indico.ictp.it/event/10697/> /*

**

**


Davide Racco (ETH, Zurich)

*“Utilizing the Causal Spectrum of Gravitational Waves: Implications for 
Pulsar Timing Arrays"*


_Abstract_

The low-frequency part of a primordial gravitational wave spectrum 
generated by local physics in a wide class of phenomena (such as a phase 
transition), is largely fixed by causality, offering a clean window into 
the early Universe. The physics of low-frequency modes allows to probe 
in a model-independent way the Hubble rate at the time of GW production, 
the equation-of-state of the Universe at subsequent times and the 
presence of free-streaming particles at primordial epochs.


I will highlight the importance of these considerations for the GW 
background recently measured at Pulsar Timing Arrays, where the Standard 
Model has an unavoidable and distinctive effect on a primordial GW signal.


<https://indico.ictp.it/event/10616/>

This is a hybrid event. *To join via Zoom*:

Zoom link: https://zoom.us/j/93869648047


Meeting ID: 938 6964 8047

Password: 756183