Crystal electric field and possible coupling with phonons in Kondo lattice <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi mathvariant="normal">CeCuGa</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math>

We investigate the magnetic and crystal electric field (CEF) states of Kondo lattice system CeCuGa3 by muon spin relaxation (muSR), neutron diffraction, inelastic scattering (INS) measurements. A noncentrosymmetric BaNiSn3-type tetragonal structure (space group I4mm) is inferred from x-ray as well powder diffraction. The low-temperature susceptibility heat capacity data show an anomaly near 2.3 - 2.5~K associated with long range ordering, which further confirmed muSR diffraction data. collected at 1.7 K shows presence Bragg peaks indexed incommensurate propagation vector k = (0.148, 0.148, 0) best described a longitudinal density wave ordered moments lying in ab-plane. An analysis INS based on CEF model reveals two excitations 4.5 meV 6.9 meV. suggest overall splitting 20.7 meV, however excitation between 20 30 very broad weak our data, but could provide evidence level this energy agreement entropy. Our CEF-phonon indicates that have their origin coupling (i.e. one peak into peaks, called vibron), 28.16 similar to case CeCuAl3 CeAuAl3.