Study of baryon correlations in e+e- annihilation at 29 GeV

Baryon correlations in Pythia

We present the results from our investigation of angular correlations between baryons pairs in the Pythia8 event generator. We show how colour reconnection models and hadronization mechanisms influence such angular correlations and in particular address the effect of gluons on the baryon production mechanism in the Lund string fragmentation model. We conclude by discussing the new theoretical ideas in comparison with the ALICE pp collision results for the baryon angular correlations. We propose a hypothesis for suppressing baryons produced in gluon jets and show how that may influence the angular correlations.

What can we learn from femtoscopic and angular correlations of identified particles in ALICE?

Two-particle correlations have proven to be a robust tool which allow the exploration of many physics phenomena present in high-energy particle collisions. In this work, two techniques, namely femtoscopic and angular correlations of identified particles, are discussed the most recent results of both of them obtained from pp and Pb-Pb collisions recorded by the ALICE detector are presented.

Exploration of particle production mechanisms via angular correlations of π, K, p, Λ with ALICE in pp collisions at √S = 7 TeV

Two-particle correlations as a function of Δη and Δφ are used in many colliding systems to study a wide range of physical phenomena. Examples include the collective behavior of the quark-gluon plasma medium, jets, quantum statistics or Coulomb effects, conservation laws, and resonance decays. In this work, measurements of the correlations of identified particles and their antiparticles (for π, K, p, Λ) are reported in pp collisions at √s = 7 TeV at low transverse momenta. The analysis reveals differences in particle production between baryons and mesons. The correlation functions for mesons exhibit the expected peak dominated by the effects of mini-jet fragmentation and are reproduced well by general purpose Monte Carlo generators. For baryon pairs where both particles have the same baryon number, an anti-correlation structure is observed instead of a peak centered at (Δη, Δφ) = (0, 0); an observation which presents a challenge to models typically used to describe pp data (PYTHIA, PHOJET). This baryon anti-correlation is further interpreted in the context of baryon production mechanisms in the fragmentation processes.

Clocking hadronization in relativistic heavy-Ion collisions with balance functions

A novel state of matter has been hypothesized to exist during the early stage of relativistic heavy-ion collisions, with normal hadrons not appearing until several fm/c after the start of the reaction. To test this hypothesis, correlations between charges and their associated anticharges are evaluated with the use of balance functions. It is shown that late-stage hadronization is characterized by tightly correlated charge-anticharge pairs when measured as a function of relative rapidity.