Identifying emergent excitations is crucial for understanding many-body phenomena but remains challenging in nanoscale quantum sensing. Conventional methods based on second-order correlations are often unable to distinguish different excitation types due to their similar spectral signatures, whereas higher-order correlations contain richer information that reveals their distinct nature. Here, we propose a fourth-order cumulant spectroscopy that diagnoses realistic spin and pseudospin excitations emerging from interacting spin systems based on their different correlation structure. By employing a quantum sensor, we extract both second- and fourth-order time-ordered correlations and construct their cumulant spectra, enabling unambiguous identification of different excitation types. This approach is robust against environmental interference and may offer a powerful tool for probing emergent excitations in quantum materials at the nanoscale.

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• Quantum correlations in quantum information
• Quantum protocols
• Quantum sensing