# Baza wiedzy: Politechnika Warszawska

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## Transverse Momentum Fluctuations in Proton-Proton and Beryllium-Beryllium Interactions at the SPS Energies

### Tobiasz Czopowicz

#### Abstract

The analysis of transverse momentum fluctuations is one of the most important tools for studying the earliest stage of nuclear collision. Results are expected to help to locate the critical point of the strongly interacting matter. Inspired by interesting results from NA49, NA61/SHINE program assumed performing five beam energy scans. Proton and beryllium beam energy scans were the first two performed (followed by xenon, argon and partial lead scans). This thesis summarizes the analysis of transverse momentum fluctuations quantified by three strongly intensive measures (Δ[PT,N], Σ[PT,N] and ΦpT) in proton-proton collisions at beam momenta 20, 31, 40, 80 and 158 GeV/c and beryllium-beryllium interactions at beam momenta (per nucleon) 19A, 30A, 40A, 75A and 150AGeV/c in four centrality intervals (0–5%, 5–10%, 10–15% and 15–20%). All the data was recorded by the NA61/SHINE experiment at the CERN Super Proton Synchrotron. For the first time, the fluctuation results are corrected for off-target interactions as well as for other detector and reconstruction inefficiencies including trigger bias. Results are compared with string-resonance models (EPOS and UrQMD) as well as previous and currentNA49 studies and preliminaryNA61/SHINE results from the argon beam energy scan. In most cases, the models were found to not reproduce the results well. The energy dependencies of fluctuation measures for p+p and 7Be+9Be did not show any non-monotonic behavior that could be expected for the critical point. An independent analysis of 40Ar+45Sc also shows smooth energy dependencies. Therefore, it can be concluded, that so far the analysis did not reveal clear signatures of the critical point. In the nearest future the search for the critical point will continue in 129Xe+139La and 208Pb+208Pb interactions in the NA61/SHINE experiment.
Identyfikator pozycji
WUTc75c4d8e7db64132a2e9f870a979dd16
Rodzaj dyplomu
Praca doktorska
Autor
Tytuł w języku angielskim
Transverse Momentum Fluctuations in Proton-Proton and Beryllium-Beryllium Interactions at the SPS Energies
Język
(en) angielski
Jednostka dyplomująca
Wydział Fizyki (WF)
Dyscyplina nauki
fizyka / dziedzina nauk fizycznych / obszar nauk ścisłych
Status pracy
Obroniona
17-05-2018
Promotor
Recenzenci zewnętrzni
Iwona Grabowska-Bołd Iwona Grabowska-Bołd Afiliacja nieokreślona
Krzysztof Piasecki Krzysztof Piasecki Afiliacja nieokreślona
Paginacja
84
Słowa kluczowe w języku angielskim
fluctuations, transverse momentum, critical point, high-energy heavy-ion collisions, physics, NA61/SHINE, CERN
Streszczenie w języku angielskim
The analysis of transverse momentum fluctuations is one of the most important tools for studying the earliest stage of nuclear collision. Results are expected to help to locate the critical point of the strongly interacting matter. Inspired by interesting results from NA49, NA61/SHINE program assumed performing five beam energy scans. Proton and beryllium beam energy scans were the first two performed (followed by xenon, argon and partial lead scans). This thesis summarizes the analysis of transverse momentum fluctuations quantified by three strongly intensive measures (Δ[PT,N], Σ[PT,N] and ΦpT) in proton-proton collisions at beam momenta 20, 31, 40, 80 and 158 GeV/c and beryllium-beryllium interactions at beam momenta (per nucleon) 19A, 30A, 40A, 75A and 150AGeV/c in four centrality intervals (0–5%, 5–10%, 10–15% and 15–20%). All the data was recorded by the NA61/SHINE experiment at the CERN Super Proton Synchrotron. For the first time, the fluctuation results are corrected for off-target interactions as well as for other detector and reconstruction inefficiencies including trigger bias. Results are compared with string-resonance models (EPOS and UrQMD) as well as previous and currentNA49 studies and preliminaryNA61/SHINE results from the argon beam energy scan. In most cases, the models were found to not reproduce the results well. The energy dependencies of fluctuation measures for p+p and 7Be+9Be did not show any non-monotonic behavior that could be expected for the critical point. An independent analysis of 40Ar+45Sc also shows smooth energy dependencies. Therefore, it can be concluded, that so far the analysis did not reveal clear signatures of the critical point. In the nearest future the search for the critical point will continue in 129Xe+139La and 208Pb+208Pb interactions in the NA61/SHINE experiment.
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Jednolity identyfikator zasobu
https://repo.pw.edu.pl/info/phd/WUTc75c4d8e7db64132a2e9f870a979dd16/
URN
urn:pw-repo:WUTc75c4d8e7db64132a2e9f870a979dd16

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