REMINDER - High Energy Physics Seminar next week TODAY (Gorji)

[HECAP - Margherita Di Giovannantonio]

*_HIGH ENERGY PHYSICS SEMINAR_* - https://indico.ictp.it/event/10634/*__*



*Thursday, 15 February* 2024, at *16:00*  - *LUIGI STASI SEMINAR ROOM *

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Mohammad Ali Gorji (ICCUB,University of Barcelona)

*“Primordial-Tensor-Induced Stochastic GWs: Explaining the Recent PTA 
Signal With No PBH Production”*

_Abstract_

Recently, pulsar timing array (PTA) collaborations announced evidence 
for an isotropic stochastic gravitational wave (GW) background. The 
origin of the PTA signal can be astrophysical or cosmological. In the 
latter case, the so-called secondary scalar-induced GW scenario is one 
of the viable explanations, but it has a potentially serious issue of 
the overproduction of primordial black holes (PBHs) due to the enhanced 
curvature perturbation. We present a new interpretation of the PTA 
signal. Namely, it originated from an extra spectator tensor field that 
exists on top of the metric tensor perturbation. As the energy density 
of the extra tensor field is always subdominant, it cannot lead to the 
formation of PBHs. Thus our primordial-tensor-induced scenario is free 
from the PBH overproduction issue.

Based on arXiv:2302.14080 and arXiv:2307.13109.



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


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

Zoom link: https://zoom.us/j/96016347698

Meeting ID: 960 1634 7698

Password: 387838