5 papers
Scalars at the Cosmological Collider: Full Shapes of Tree Diagrams and Bispectrum Searches using Planck Data
Soubhik Kumar, Qianshu Lu, Zhong-Zhi Xianyu +1
The Cosmological Collider (CC) provides a unique opportunity to probe the particle spectrum and fundamental interactions at extremely high energies. Massive particles, via their de…
Cosmological Collider Searches beyond the Hubble Scale with Planck Data
Soubhik Kumar, Qianshu Lu, Zhong-Zhi Xianyu +1
Searches for primordial non-Gaussianity (NG) has the potential to not only reveal the physics of cosmic inflation, but also the structure of fundamental interactions at the highest…
Freezing-in the Axiverse
Christopher Dessert, Soubhik Kumar, Joshua T. Ruderman
The presence of multiple light axions in the infrared is a generic feature of many ultraviolet (UV) scenarios. In many cases the number of axions is o…
Not-quite-primordial black holes
Wenzer Qin, Soubhik Kumar, Priyamvada Natarajan +1
We propose a new mechanism for the formation of seeds of supermassive black holes at early cosmic epochs. Enhanced density fluctuations with amplitudes that are not large enough to…
Early Galaxies from Rare Inflationary Processes and JWST Observations
Soubhik Kumar, Neal Weiner
Rare Poisson processes (PP) during cosmic inflation can lead to signatures that are localized in position space and are not well captured by the standard two- or higher-point corre…