Hanbury-Brown/Twiss Interferometry for Relativistic Heavy-Ion Collisions: Theoretical Aspects

Bose Einstein and Fermi Dirac interferometry in particle physics

“…From Eqs. (11) and ( 12) one finds the approximate relation r KP ≃ 2r G which is verified experimentally. For example, in a study [22] of the BEC of the π ± π ± system emerging from the decay of the Z 0 boson one obtained r G = 0.955 ± 0.012(stat.)…”

“…In parallel to the BEC studies of hadronic final states produced in particle reactions, extensive pion-pair correlation analyses were and are applied to heavy ion collisions in order to explore the characteristics of these rather complex reactions [6,11,12]. A compilation, taken from Ref.…”

Hanbury Brown--Twiss Interferometry and Collectivity in Small Systems

“…S can be thought of in essence as a quantum-mechanical phase space (or 'Wigner') distribution [26] which roughly characterizes the probability to emit a particle from position x with momentum K. The step from (2) to (3) makes use of the so-called "smoothness assumption" [27] which is well-justified for large sources such as A-A collisions, but becomes questionable in pp and p-A collisions. This assumption will be relaxed in the full analysis which follows, although its effects turn out to be mostly negligible when evaluated quantitatively.…”

“…These effects will be neglected in this study, meaning that λ( K) = 1. 2 In the special case of a perfectly Gaussian source (and making use of the smoothness assumption) [26], one can perform the Fourier integrals in (3) analytically, yielding an exact relation between the R 2 ij ( K) and space-time variances of the underlying source [33,34]:…”

Illuminating Light

“…HBT correlations, as explained in chapter 2, are able to probe the space-time evolution of the QGP by measuring the two particle correlation function C(Q inv ), as it is sensitive to the size of the emitting source [17,61,62,198,199]. As direct photons escape the medium when they are produced, they are not affected by rescattering and hadronization effects, which makes direct photon HBT uniquely suited to access information of the early stage of the collision [200,201].…”