Production of pion pairs with symmetric momenta in the transverse-momentum region 0. 5< or =P/sub perpendicular/< or =2. 0 GeV/c in the pp collisions at 70 GeV

The slope of the invariant cross section of the process pp ..-->.. ..pi../sup +/ ..pi../sup -/+X varies near 1 GeV/c as a function of P/sub perpendicular/. If the slope is described by the sum of the two exponents, then the exponents must be equal to 12.3 +- 0.9 (GeV/c)/sup -1/ and 8.7 +- 0.6 (GeV/c)/sup -1/. The experimental values in the region P/sub perpendicular/>1 GeV/c are much higher than the values predicted by the QCD model (Ref. 1) and by the CIM model (Ref. 2) for inelastic collisions.