the height $H$ over the detector at which the interaction took place. However, it can be estimated if one assumes that the two rings observed with radii $r_1=1.75$ cm and $r_2=5$ cm are produced, correspondingly, by forward and backward moving (in c.m.s.) partons. Using the transformation of angles from target ($t$) to c.m.s. ($c$) $$\tan \frac {\theta _c}{2}\approx \gamma \theta _t   \;\;\;\; and \;\;\;\;
\frac{\theta _{1t}}{\theta _{2t}}=\frac{r_1}{r_2}                      \label{tan}$$ and assuming the symmetry of rings $\theta _{2c}=\pi - \theta _{1c}$, one gets $\theta _{1c}\approx 61^o$ and $\gamma \approx 2.3\cdot 10^3$. The angle in the target rest system is $\theta _{1t} \approx 2.6\cdot 10^{-4}$ and the height $H=r_1/\theta _{1t} \approx 68$ m. It corresponds rather well to the experimental estimates obtained by three different methods [@kon]. The most reliable of them give values ranging from 50 m to 100 m. Even though the observed angles were quite small in the target rest system, at LHC they would correspond to large c.m.s. angles about 60$^o$ - 70$^o$. The peaks in the angular distribution of jets over the background at these angles would be observable [@ag; @dst].

The substructure similar to that in Fig. 3 was also found in PbPb-interactions at 158 GeV. The 