Averaging and the Shape of the Correlation Function

Abstract

A brief pedagogical introduction to correlation femtoscopy is given. We then focus on the shape of the correlation function and discuss the possible reasons for its departure from the Gaussian form and better reproduction with a Lévy stable distribution. With the help of Monte Carlo simulations based on asymmetric extension of the Blast-Wave model with resonances we demonstrate possible influence of averaging over many events and integrating over wide momentum bins on the shape of the correlation function. We also show that the shape is strongly influenced by the use of the one-dimensional parametrisation in the q i n v variable.

Investigating the pion source function in heavy-ion collisions with the EPOS model

“…it was shown that the α parameter has no strong dependence on k T , and a decreasing trend with centrality was observed. Although in experiment no clear k T dependence have been observed, other phenomenological studies found similar increasing behavior of the Lévy exponent 28,29. The reason behind these apparent contradictions are not clear at this moment.…”

“…Although in experiment no clear k T dependence have been observed, other phenomenological studies found similar increasing behavior of the Lévy exponent. 28,29 The reason behind these apparent contradictions are not clear at this moment.…”

Pion Interferometry with Lévy-Stable Sources in sNN = 200 GeV Au + Au Collisions at STAR

“…Such distributions were found to be good candidates to describe experimental measurements [17][18][19], as well as the source shape in event generator models such as EPOS [13,14]. The reason for the appearance of the apparent α < 2 power law behavior is yet to be understood in detail; at different collision energies and different collision systems, there can be many various competing phenomena, such as jet fragmentation [23,24], critical behavior [25], event averaging [26,27], resonance decays [13,14,28], and anomalous diffusion [28,29].…”

Kvantumstatisztikai korrelációs függvények elméleti és kísérleti vizsgálata nehézion-ütközésekben

“…Léteznek olyan magyarázatok az α = 2 meggyelésre, amelyek kísérleti eektusokon alapulnak [67,68,123] Az α paraméter centralitásfüggésére nem létezik elméleti jóslat vagy magyarázat. Külön érdemes kiemelni, hogy az elterjedten használt Cauchy-és Gauss-esetek (rendre α = 1, α = 2) egyikét sem er®sítik meg az adatok.…”

“…Ez az eredmény azért is fontos, mert olyan modellek és megfontolások, melyek az α nem 2 és nem 1 eredetére adnak magyarázatot, csak akkor elfogadhatóak, ha a centralitásfüggést is képesek reprodukálni. Egyel®re ilyen modellr®l, elméleti számolásról nem tudok, de az α értékének eredetére vonatkozó vizsgálatok vannak [67,68,123]. 46. ábra.…”