2025/04/07 by An, Haipeng, Qin, Zhehan, Xianyu, Zhong-Zhi +1 · 2 citations
#Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.2504.05389
Can a stationary stone radiate gravitational waves (GWs)? While the answer is typically "no" in flat spacetime, we get a "yes" in inflationary spacetime. In this work, we study the stationary-stone-produced GWs in inflation with a concrete model, where the role of stones is played by massive higher-spin particles. We study particles of spin-2 and higher produced by helical chemical potentials, and show that the induced GWs feature a scale-invariant and helicity-biased power spectrum in the slow-roll limit. Including slow-roll corrections leads to interesting backreactions from the higher-spin boson production, resulting in an intriguing scale-dependence of GWs at small scales. Given the existing observational and theoretical constraints, we identify viable parameter regions capable of generating visibly large GWs for future observations.