Production of Omega and Xi hyperons in proton-proton collisions at √s =13 TeV using the ALICE detector at the Large Hadron Collider

doctoral thesis

• Title (croatian): Proizvodnja Omega i Ksi hiperona u sudarima protona pri √s=13 TeV-a proučavana pomoću detektora ALICE na Velikom Hadronskom Sudarivaču
• Author: David Karatović
• Mentor: Mirko Planinić (mentor)
• Committee member: Davor Horvatić (predsjednik povjerenstva)
• Committee member: Dinko Ferenček (član povjerenstva)
• Committee member: Mirko Planinić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2024-05-08, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics
• Universal decimal classification (UDC): 53 - Physics

Abstract

Investigation of the production of strange particles in high-energy collisions is one of the ways to study quark-gluon plasma (QGP). One of the first suggested signatures of QGP was the phenomenon of strangeness enhancement. It was long considered that it is only possible to have QGP in heavy ion collisions, and that the proton-proton system is too small to produce QGP. After strangeness enhancement was observed in heavy ion collisions, with an increase in collision energy at the LHC, it was also observed in proton-proton collisions, in which we didn’t expect to find quark-gluon plasma, together with some of the other QGP signatures. With higher LHC energies, the question arises: will the production of strangeness continue with a growing trend, as it does for other systems, or will saturation occur for smaller systems, as it does in lead-lead collisions? This study analyses data collected by the ALICE detector at the LHC from 2016-2018 during 13 TeV proton-proton collisions. The analysis investigates the dependence of Xi and Omega hyperon yields on their transverse impulse, as well as on the multiplicity of collisions. The main analysis is done on highest multiplicity events. This fills a gap in multiplicity in which there are currently few results available for collisions of protons. The data used is comparable to data from proton-lead and peripheral lead-lead collisions and the aim is to see if the results agree, or if there is a saturation in strangeness production in pp collisions. As a consequence, certain models that try to explain strangeness enhancement would be either confirmed or disproved. The results show great agreement with results from collisions of other systems, namely lead-lead and proton-lead, and different collision energies. This confirms that strangeness enhancement is present in high multiplicity proton-proton collisions. The number of produced strange particles in the final state of the collision depends on the final multiplicity of the collision, and not on the energy or the type of particles colliding.

Abstract (english)

Istraživanje proizvodnje stranih čestica pri visokoenergetskim sudarima jedan je od načina proučavanja kvarkovsko-gluonske plazme. Jedan od prvih potpisa kvarkovsko-gluonske plazme je bio fenomen povećanja stranosti. Dugo vremena je znanstveni konsenzus bio da je kvarkovsko-gluonsku plazmu moguće stvoriti samo u sudarima teških iona, jer je sustav u sudarima protona premalen. Nakon što je povećanje stranosti primijećeno u sudarima teških iona, povećanjem energije sudara na LHC-u primijetilo se i u proton-proton sudarima, u kojima nismo očekivali postojanje kvarkovsko-gluonske plazme. Sa sve većim energijama sudara na LHC-u postavlja se pitanje: hoće li se trend povećanja stranosti nastaviti kao za druge sustave, ili ́će doći do zasićenja u sustavu protona kao što se dogodi u sudarima teških iona? U ovom istraživanju analiziraju se podaci prikupljeni ALICE detektorom na LHC-u 2016.-2018. u sudarima protona na energijama centra mase 13 TeV-a. U analizi se određuje ovisnost broja proizvedenih Ksi i Omega hiperona o njihovu transverzalnom impulsu, kao i o multi-plicitetu sudara. Glavna tema istraživanja je područje najvišeg multipliciteta. Time se popunjuje područje u kojem za protone trenutno ima malo dostupnih rezultata. Ono je usporedivo s podacima iz perifernih Pb-Pb sudara te je cilj vidjeti slažu li se rezultati međusobno ili dolazi do zasićenja proizvodnje stranosti u proton-proton sudarima. Iz toga bi se potvrdili ili opovrgnuli određeni modeli koji pokušavaju objasniti povećanu proizvodnju stranih čestica. Rezultati su u odličnom slaganju s rezultatima dobivenim iz drugih tipova sudara, sudara proton-olovo i olovo-olovo, pri različitim energijama. Time je potvrđeno postojanje povećanja stranosti u sudarima protona pri najvišim multiplicitetima. Broj proizvedenih čestica ovisi samo o konačnom multiplicitetu sudara, a ne o energiji i tipu čestica koje sudaramo.

• Keywords: Quark-gluon plasma; strangeness enhancement; strange quark; hyperon; Xi; Omega; proton-proton collision; high multiplicity; ALICE detector
• Keywords (croatian): kvarkovsko-gluonska plazma; povećanje stranosti; strani kvark; hiperon; Ksi; Omega; proton-proton sudari; visoki multiplicitet; ALICE detektor
• Language: english
• URN:NBN: urn:nbn:hr:217:532859
• Promotion: 2024
• Project: Number: IP-2018-01-4108; Title: Demistificiranje dvočestičnih korelacija u pp sudarima s nadograđenom komorom vremenske projekcije; Title: Demystification two particle correlations in pp collisions with the upgraded time projection chamber; Acronym: TPCwithTPC; Leader: Mirko Planinić; Jurisdiction: Croatia; Funder: Hrvatska zaklada za znanost; Funding stream: Research Projects
• Study programme: Title: Doctoral study; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti u području prirodnih znanosti (doktor/doktorica znanosti u području prirodnih znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-06-14 14:03:04