We present Rossiter-McLaughlin observations of the transiting super-Earth 55 Cnc e collected during six transit events between January 2012 and November 2013 with HARPS and HARPS-N. We detect no radial-velocity signal above 35 cm s ^ { -1 } ( 3 \sigma ) and confine the stellar v \sin i _ { \star } to 0.2 \pm 0.5 km s ^ { -1 } .
The star appears to be a very slow rotator , producing a very low amplitude Rossiter-McLaughlin effect .
Given such a low amplitude , the Rossiter-McLaughlin effect of 55 Cnc e is undetected in our data , and any spin–orbit angle of the system remains possible .
We also performed Doppler tomography and reach a similar conclusion .
Our results offer a glimpse of the capacity of future instrumentation to study low amplitude Rossiter-McLaughlin effects produced by super-Earths .