Contour map of the HDO(1₁₀–1₁₁) emission (black contours) integrated between –0.3 and +10.7 km ss^-1 superimposed onto the continuum image at 3.7 mm (magenta). The HDO contour levels range from 3σ (33 mJy km s^-1 beam^-1) to 5σ by 1σ. Continuum contour levels range from 30 (~20σ) to 90% of the peak value (16 mJy), and identify the driving protostar L1448-mm. The filled ellipse in the lower left corner shows the synthesised PdBI beam (HPBW): 6″̣29 × 4″̣87. The black arrow points in the direction of the jet (PA = –21°) identified by Guilloteau et al. (1992) through SiO emission. The dashed lines identify the sketch of the limits of the conical blue-shifted (+6, +8 km s^-1) cavity observed in CO(1–0) at PdBI by Bachiller et al. (1995).