Electron-spectroscopy study of YbX<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Cu</mml:mi></mml:mrow><mml:mrow><mml:mn>4</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>(X=Ag,Au,Pd)

We have studied the electronic structure of the heavy-electron compounds YbX${\mathrm{Cu}}_{4}$, with X =e/rAg,Au,Pd, using x-ray photoemission and bremsstra...