Event topology and multiplicity dependence of K∗(892)0 production in proton+proton collisions with ALICE at the LHC and probing TeV collisions through particle production and transport properties

Abstract

“Look deep into nature and then you will understand everything better” –Albert Einstein We have studied the K⇤(892)0 production in its hadronic decay channel K±⇡⌥ in pp collisions at ps = 5.02 and 13 TeV in the ALICE at the Large Hadron Col lider (LHC) in a more di↵erential manner using event-topology and multiplicity to understand its production mechanism. K⇤0 being a resonance particle having a lifetime of 4.16 fm/c is a suitable candidate to probe the presence and properties of hadronic phase of the produced system in ultra-relativistic hadronic and nu clear collisions. K⇤0 is sensitive to the hadronic phase e↵ects such as rescattering and regeneration processes, which might a↵ect its yield and shape of the trans verse momentum spectra. In addition, event shape observables like transverse spherocity are sensitive to the hard and soft processes. Therefore, they are use ful tools to distinguish the isotropic and jetty-dominated events in pp collisions. Studying the dependence of the yield of resonance on transverse spherocity and multiplicity allows us to understand the resonance production mechanism with event topology and system size, respectively. In this thesis, we observe that low-multiplicity pp collisions are more dominated by jetty-like events whereas high-multiplicity pp collisions are highly populated with isotropic-like events. In high-multiplicity pp collisions, it is found that the low transverse momentum region is more dominated by isotropic-like events whereas the high transverse momentum region is dominated mostly by jetty-like events. Moreover, we have also studied the K⇤0 integrated yield, mean transverse momentum and particle ratio to the long-lived stable hadrons. Furthermore, the measurements in small systems done using the ALICE detector are compared with results from models such as PYTHIA8, EPOS-LHC, etc. Here, several phenomenological studies are carried out to understand the freeze-out condition in pp collisions which includes the study of chemical freeze-out parameters with a constraint of event topology and multiplicity, and energy and multiplicity dependence of the kinetic freeze out parameters.