  The pairing of composite fermions (CFs), electron-flux quasi-particles, is
commonly proposed to explain the even-denominator fractional quantum Hall state
observed at $\nu=5/2$ in the first excited ($N=1$) Landau level (LL) of a
two-dimensional electron system (2DES). While well-established to exist in the
lowest ($N=0$) LL, much is unknown about CFs in the $N=1$ LL. Here we carry out
geometric resonance measurements to detect CFs at $\nu=5/2$ by subjecting the
2DES to a one-dimensional density modulation. Our data, taken at a temperature
of 0.3 K, reveal no geometric resonances for CFs in the $N=1$ LL. In stark
contrast, we observe clear signatures of such resonances when $\nu=5/2$ is
placed in the $N=0$ LL of the anti-symmetric subband by varying the 2DES width.
This finding implies that the CFs' mean-free-path is significantly smaller in
the $N=1$ LL compared to the $N=0$ LL. Our additional data as a function of
in-plane magnetic field highlight the role of subband index and establish that
CFs at $\nu=5/2$ in the $N=0$ LL are more anisotropic in the symmetric subband
than in the anti-symmetric subband.
