Femtoscopic and Nonfemtoscopic Two-Particle Correlations in 𝐴+𝐴 and 𝑝+𝑝 Collisions at RHIC and LHC Energies

Figure 1

The cartoon of the particlization at the hypersurface 𝜎₀ (solid line) and spectra formation at 𝜎 (dashed line). The very initial system forms at the hypersurface 𝜎_𝑖𝑛 (double line) and then evolves. The Gauss theorem in (10) and (11) is applied to enclosed hypersurface 𝜎₀⊕𝜎. In the case of large opacity 𝑓^𝜎_esc(𝑥₁,𝑝₁)≈0 for particle 1, also is small for particle 2, and so 𝑝_𝜇Δ𝜎^𝜇₀(𝑥₁)𝑓^𝜎_esc(𝑥₁,𝑝)≈0, while for the distribution function 𝑓(𝑥₁,𝑝) the similar value 𝑝_𝜇Δ𝜎^𝜇₀(𝑥₁)𝑓(𝑥₁,𝑝) is not zero, and for 𝑝=𝑝₁ it is negative if Δ𝜎₀ is a nonspace-like site of the hypersurface 𝜎₀.