Role of Fluorescence yields, Coster-Kronig transitions and ionization theories on L X-ray intensity ratios of Au

► New data for L X-ray production from Au using low energy protons are reported. ► Effects of Fluorescence yields and Coster-Kronig transitions on it are analyzed. ► Stringent comparison of measured values with theoretical models has been presented.► Their contribution to these phenomena and current growth has been highlighted. ► Prospects for supplementary effort are discussed.