Gideon McFarland, Starkenburg Group
"A Journey Through The Space Between: Probing The Expansion of The Universe with Cosmic Voids in LSST"
The nature of dark energy, the mysterious source of the expansion of the Universe, continues to elude cosmologists to this day. We can learn about dark energy by mapping and characterizing cosmic voids: nearly empty regions of the Universe that make up the space between galaxies and galaxy clusters. Using the exceptional depth and sky area of the now operational Rubin Observatory, we will gain the statistical power to make real constraints on cosmology using the void size function—the number density of voids as a function of their radius. However, inaccurate galaxy redshift estimates remain a significant source of error for finding voids, requiring significant correction to avoid losing constraining power. In this work, I will show how we can mitigate the effects of redshift errors by finding spherical voids. This spherical assumption partially improves the stability and consistency of our void finding, while the net effect on the void size function depends heavily on the galaxy dataset. Careful construction of Rubin's galaxy catalog can reduce our total information loss, and fine-tuning our void definition can help us approximate portions of the true void size function that would be measured from accurate redshifts. With the continued development of this correction technique—and new science-ready data on the horizon—the prospect of shining a new light on the nature of dark energy will hopefully soon become a reality.
Yulun Miao, Schmitt Group
"New Physics Search in Three Massive Gauge Boson Production with Effective Field Theory"
Large Hadron Collider (LHC) and Compact Muon Solenoid (CMS) are essential tools to study elementary particles and interaction of elementary particles. Currently, with no positive signal for Physics Beyond Standard Model (BSM) at LHC energy scale, New Physics search targeting modified coupling organized in Standard Effective Theory (SMEFT) framework becomes a growing topic in high energy physics. In this talk, I will present an example of conducting such a search targeting deviation in quartic gauge coupling, triple gauge coupling, and higgs-gauge coupling with three massive gauge boson production. The analysis features 8 signal regions in boosted region and limit setting for 12 mass dimension 6 Wilson Coefficients and 20 mass dimension-8 Wilson Coefficients.