the solid one) constitutes the noticeable part at low masses. The formula (\[ll\]) must be valid in the vicinity of the resonance peak. Thus we use it for masses larger than 0.4 GeV only.

The excess of masses larger than 0.9 GeV is ascribed to $\phi $-meson not considered here. The estimated value $w=0.19$ corresponds to the lowest possible contribution of Cherenkov gluons because the fit in the region 0.75 - 0.9 GeV is most unfavorable for it. This is clearly seen in Fig. 2 where the solid line is systematically below experimental points at 0.75 - 0.8 GeV and above them at 0.8 - 0.9 GeV.

One would expect slightly lower $p_T$ for low-mass dilepton pairs from coherent Cherenkov processes than for incoherent scattering at higher masses. Qualitatively, this conclusion is supported by experiment [@1a]. The Cherenkov dominance region of masses from 400 MeV to 600 MeV below the $\rho $-resonance has softer $p_T$-distribution compared to the resonance region from 600 MeV to 900 MeV filled in by usual incoherent scattering. More accurate statements can be obtained after the microscopic theory of Cherenkov gluons developed.

Whether the in-medium Cherenkov gluonic effect is as strong as shown in Fig. 2 