Observation of large-scale anisotropy of very high-energy cosmic-ray protons with LHAASO-KM2A

We present a measurement of large-scale anisotropies in high-purity protons utilizing the Large High Altitude Air Shower Observatory (LHAASO). We analyzed data collected over three years from the kilometer-squared array (KM2A). Proton data was selected using a cut based on the ratio of muonic to electromagnetic components, akin to the gamma/background discrimination method used in KM2A. The proton sample achieved a purity of up to 80\%, with reconstructed energies ranging from 10 TeV to 220 TeV. We conducted an analysis of the energy evolution of dipole anisotropy in protons within this energy range and identified that the turnover energy in amplitude and phase occurs at a lower energy compared to samples of heavier nuclei.