Year: 2026
Type: preprint
Abstract: Femtoscopic correlations in proton-proton and heavy ion collisions are commonly calculated using emission sources from microscopic transport models, where emitted particles are represented by classical phase-space points with simultaneously specified positions and momenta. This point-emitter picture neglects the finite phase-space localization required by quantum mechanics, which can become relevant when the localization scale approaches the femtoscopic source size, particularly in small collision systems. We formulate a quantum treatment by replacing each transport phase-space point with a minimum-uncertainty Gaussian phase-space distribution. Finite localization then induces both spatial and momentum smearing; in the presence of coordinate-momentum correlations, the latter produces a nontrivial modification of the emission source. Using proton--proton collisions at $\sqrt{s}=7~\mathrm{TeV}$ simulated with the microscopic Parton--Hadron--String Dynamics transport approach, we show that this effect significantly modifies the proton-pair source and its momentum correlation. Our results expose a quantum localization effect overlooked in transport-based femtoscopy and establish the regime in which the classical point-emitter approximation is valid.
Source: arXiv (Cornell University)
Institutions: Goethe University Frankfurt, GSI Helmholtz Centre for Heavy Ion Research, Centre National de la Recherche Scientifique, Frankfurt Institute for Advanced Studies, Laboratoire de Physique Subatomique et des Technologies Associées, IMT Atlantique, Institut National de Physique Nucléaire et de Physique des Particules, Université de Nantes, Nantes Université
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221152944