Abstract

Contributed Talk - Splinter LargeScale

Thursday, 10 September 2026, 14:15   (MW-2235)

Probing Parity Violation with Weak Lensing Trispectrum

Sijin Chen, Zhengyangguang Gong, Jiamin Hou
LMU Munich

Investigating parity violation on cosmological scales addresses fundamental questions in modern physics and provides a well-defined test of symmetry properties in cosmological observables. Possible parity-violating signatures in cosmological observables would offer a connection between early-Universe physics and the large-scale distribution of matter. Observational searches for such signals in the cosmic microwave background and large-scale structure therefore provide a complementary approach to probing physics beyond standard cosmological descriptions. In this work, we study parity properties of the weak gravitational lensing field using the angular trispectrum of the lensing convergence. Weak lensing probes the projected matter distribution along the line of sight and is sensitive to the non-Gaussian structure of large-scale density fluctuations. While most existing weak lensing analyses focus on parity-even statistics, the trispectrum allows for the construction of parity-odd configurations that vanish in parity-conserving scenarios. We use a parity-odd trispectrum template based on previous work in the context of the cosmic microwave background and investigate its projection onto the weak lensing convergence field. The theoretical framework explicitly accounts for the geometric structure of the trispectrum, angular mode coupling, and projection effects arising from the lensing kernel. We implement a numerical pipeline to evaluate the resulting weak lensing trispectrum and study its basic properties. Our results demonstrate that parity-odd configurations can be consistently defined for the weak lensing convergence field and that their projected trispectrum exhibits well-behaved numerical features. This work establishes a controlled theoretical and computational framework for studying parity properties of weak lensing higher-order statistics. It provides a basis for future investigations of parity symmetry using large-scale structure data.