Abstract
The strong interaction among hadrons has been measured in the past by scattering experiments. Although this technique has been extremely successful in providing information about the nucleon–nucleon and pion–nucleon interactions, when unstable hadrons are considered the experiments become more challenging. In the last few years, the analysis of correlations in the momentum space for pairs of stable and unstable hadrons measured in pp and p+Pb collisions by the ALICE Collaboration at the LHC has provided a new method to investigate the strong interaction among hadrons. In this article, we review the numerous results recently achieved for hyperon–nucleon, hyperon–hyperon, and kaon–nucleon pairs, which show that this new method opens the possibility of measuring the residual strong interaction of any hadron pair.
Highlights
The femtoscopic technique can be traced back to the first measurements of particle interferometry with photons, which were performed by Hanbury Brown & Twiss [11] during the
Results from intermediate-energy heavy-ion collisions (HICs) at the Bevalac in the mid-1980s quantitatively showed that the spatial dynamics of the system could be probed by femtoscopy, and in the following years femtoscopic s(a√tnudsdN,imNeso=hrea1vr–ee3cbeGeneetnlVy,p) Re(1rHf8o,IrC1m9(e)√,dAsiNGnNSse=(v√e2rs0Na0lNdG=ifefVe5r–)e1(n20t4Ge) xaepnVed)rit(mh2e0e,nL2tHs1)aC,nSd(P√eSsnN(e√Nrgs=NyNr5a–=n1g31e7Ts,eGiVnec)Vl(u2)d5(i2)n.2g, SIS 23), The abundance of collected data made it possible to study the three-dimensional evolution of the particle-emitting source, which is helpful in characterizing the kinematic freeze-out of different hadron species
The high statistics collected for all hyperon species in pp and p+Pb collisions measured by the ALICE Collaboration during Runs 1 and 2 at the LHC allowed unprecedented precision in the study of different interactions, including combinations that already had been studied in the past by means of scattering experiments [5,6,7, 68, 71,72,73,74] or that never had been measured before (p − and p −)
Summary
The fundamental quantity to be measured in femtoscopy is the correlation function. It is expressed as a function of the relative distance between two particles r∗ and their reduced relative momentum, k∗ = |p∗2 − p∗1|/2 in the pair rest frame, with p∗1 = −p∗2, by the Koonin–Pratt formula [33, 43]:1. The correlation functions measured in the ALICE experiment are compared with theoretical expectations obtained according to Equation 5 For this task, the λ parameters are obtained from experimental data when possible (e.g., purity, fractions of secondary particles). To account for residual contributions from the mini-jet background to the final correlations, a baseline with free parameters is multiplied with the correlation function C(k∗) used to fit the experimental data [37]. This baseline assumes different shapes depending on the pair of interest, but it contributes at most a few percent to the global correlation strength [39, 41]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
