Comparison of Source Images for Protons,π−’s, andΛ’s in6A  G

Abstract

Source images are extracted from two-particle correlations constructed from strange and nonstrange hadrons produced in 6 AGeV Au + Au collisions. Very different source images result from pp vs pΛ vs π − π − correlations. These observations suggest important differences in the space-time emission histories for protons, pions and neutral strange baryons produced in the same events.Relativistic heavy ion collisions of 1-10 AGeV produce a fireball of nuclear matter with extremely high baryon and energy density [1]. The dynamical evolution of this fireball is driven by such fundamental properties as the nuclear Equation of State (EOS) and possibly by a phase transition, e.g., to a Quark Gluon Plasma (QGP) [2,3,4,5,6]. Two-particle correlation studies, for various particle species, provide an important probe of the space-time extent of this fireball [7,8,9,10]. Recent model calculations suggest that the time scale for freeze-out of strange and multi-strange particles may be much shorter than that for non-strange particles [11,12], implying a much smaller space-time emission zone for strange particles. If this is indeed the case, then correlation studies involving strange particles may serve as important "signposts" for dynamical back-tracking into the very early stage of the collision where large energy densities are achieved [13].In this letter we compare the source properties for protons, π − 's and Λ hyperons extracted from pp, π − π − and pΛ correlation functions, as produced in 6 AGeV Au+Au collisions. These data are unique in that they constitute the first measurement of pΛ correlations. If Λ hyperons are in fact emitted from a source with a smaller spacetime extent, then between this and π − source broadening from resonance decays, one might naively expect an ordering of two-particle source sizes: R pΛ < R pp < R ππ . On the other hand, at these energies the 3-dimensional π − radii exhibit m T scaling [7,14] and this should manifest itself in the angle-averaged π − sources. Furthermore, since m T scaling can be ascribed to position-momentum correlations in the particle emission function [15], one might expect similar effects in the pp and pΛ sources. As we will show, neither an interpretation based solely on position-momentum correlations nor on naive geometrical arguments can fully account for the relative size of

Imaging of granular sources in high energy heavy ion collisions

“…It can be used to extract the source geometry pictures (source function) directly from the two-pion correlation functions. This technique has been developed and used in high energy heavy ion collisions [8][9][10][11][12][13][14][15][16][17][18][19][20].…”

p−p, p−Λ , and Λ−Λ correlations studied via femtoscopy in <

“…If one considers smaller colliding systems such as protonproton (pp) at TeV energies and assumes that the particle emitting source does not show a strong time dependence, one can reverse the paradigm and exploit femtoscopy to study the final-state interaction (FSI). This is especially interesting in the case where the interaction strength is not well known as for hyperon-nucleon (Y-N) and hyperon-hyperon (Y-Y) pairs [11][12][13][14][15][16][17][18][19]. Hyperon-nucleon and hyperon-hyperon interactions are still rather poorly experimentally constrained and a detailed knowledge of these interactions is necessary to understand quantitatively the strangeness sector in the lowenergy regime of quantum-chromodynamics (QCD) [20].…”

A femtoscopic correlation analysis tool using the Schrödinger equation (CATS)

“…Femtoscopy has been mainly employed so far to study the properties of the particle emitting source in heavy-ion collisions by analyzing particle pairs with low relative momentum undergoing a known interaction [1,2]. In heavy-ion collisions pion femtoscopy has been the most common tool to get insight into the time-space evolution of the produced medium [3][4][5][6][7][8][9][10][11][12][13]. a e-mail: dimitar.mihaylov@mytum.de b e-mail: valentina.mantovani-sarti@tum.de Unlike heavy-ion collisions, nucleon-nucleon (NN) collisions are not affected by the formation of a medium such as the Quark-Gluon-Plasma.…”

“…Femtoscopy has been mainly employed so far to study the properties of the particle emitting source in heavy-ion collisions by analyzing particle pairs with low relative momentum undergoing a known interaction [1,2]. In heavy-ion collisions pion femtoscopy has been the most common tool to get insight into the time-space evolution of the produced medium [3][4][5][6][7][8][9][10][11][12][13].…”