Signatures of CH4 and NH3 in the atmosphere of β Pictoris b

β Pictoris is a nearby (19.7 pc), young (∼ 24 Myr), bright (V = 3.85) planetary system hosting three directly imaged planets. Previous high-resolution spectroscopy of b has detected and CO but not or Combining observations across a broad wavelength range has been shown to maximise sensitivity to such weak molecular signals. We searched for previously undetected molecular species in the atmosphere of b using high-resolution near-infrared spectra. We combined 44 CRIRES+ spectral settings covering the H, K, L, and M bands and cross-correlated the extracted planetary spectra with molecular templates. For species with uncertain detectability, we weighted the observations by their molecular information content and data quality, independent of the measured candidate-species cross-correlation functions. We recover and CO at cross-correlation S/N values of approximately 200 and 50, respectively. We additionally identify tentative and signals near the expected radial velocity of b, with S/N values of approximately 5.3 and 5.7. Equivalent extractions at the same projected separation on the opposite side of the star show no comparable peaks. We classify the and signals as tentative because their cross-correlation S/N values do not fully account for possible residual systematics. If confirmed, these would be the first detections of both species in the atmosphere of b.