Examples of red giant branch stars with low dipole-mode amplitudes. Spectra are plotted as a function of the reduced frequency ν/ Δν−ε, so that radial modes (shown in blue) are close to integer values; quadrupole modes are plotted in green, octupole modes in cyan; and mixed modes can be found everywhere but their contribution is measured in the frequency range plotted in red only. The mean background component was subtracted. Top: the mixed mode pattern of KIC 9279486 can be fitted to extract seismic global parameters; middle: the mixed modes in KIC 6026983 are evidenced but their pattern cannot be fit; and bottom: the dipole modes of KIC 5810513 have very small amplitudes but can be unambiguously detected and identified as mixed modes with the method discussed in Sect. 3.3.