Unit:
Department of PhysicsLibrary of the School of Science
Author:
Plastiras Nikolaos
Supervisors info:
Βελλίδης Κωνσταντίνος, Αναπληρωτής Καθηγητής, Τμήμα Φυσικής ΕΚΠΑ
Original Title:
Κινηματική ανακατασκευή της διάσπασης DiGluino -> q qbar chargino-1(neutralino-1 W(lν)) q qbar chargino-1(neutralino-1 W(q qbar)) με την μέθοδο Recursive Jigsaw Reconstruction για την αναζήτηση Υπερσυμμετρίας σε δεδομένα του πειράματος CMS
Translated title:
Kinematic reconstruction of the DiGluino -> q qbar chargino-1(neutralino-1 W(lν)) q qbar chargino-1(neutralino-1 W(q qbar)) decay using the Recursive Jigsaw Reconstruction method for the search of Supersymmetry in data of the CMS experiment
Summary:
The Standard Model (SM), despite being undeniably successful to a great extent, fails to explain some important questions, resulting in many new theories being proposed to answer some of them. One of these is Supersymmetry (SUSY), an extension of the Standard Model, predicting for each SM particle its supersymmetric partner with a spin reduced by ħ/2. In some SUSY models, in which the conservation of a new symmetry, R - parity, is considered, the Lightest Supersymmetric Particle (LSP) must be stable. This particle, which is called neutralino-1 is a candidate for the composition of dark matter, as it is a WIMP (Weakly Interacting Massive Particle). Thus, the experimental confirmation of its existence and hence the existence of SUSY particles, is of utmost importance. Certainly, the detection of LSPs, in an experiment like CMS is difficult because these particles act like SM neutrinos meaning that they will escape the detector, leaving the missing energy as the only information. As a result, kinematic and combinatoric ambiguities arise that do not allow us to obtain information about all the properties of intermediate particles of the decay. We solve these difficulties using the method Recursive Jigsaw Reconstruction (RJR). This method uses a combination of algorithms-rules, known as Jigsaw Rules (JR’s), the application of which resolves to some extent the ambiguities in each process. Ιn this thesis, using the RestFrames software package, we apply the RJR method for the reaction DiGluino -> q qbar chargino-1(neutralino-1 W(lν)) q qbar chargino-1(neutralino-1 W(q qbar)) with the aim of its correct generation and reconstruction. In particular, we consider five scenarios for the masses of the supersymmetric particles and analyze how phase space differences affect the reconstruction of the investigated parameters.
Main subject category:
Science
Keywords:
Supersymmetry, SUSY, Standard Model, R-parity, gluino, chargino, neutralino, LSP, Recursive Jigsaw Reconstruction, RJR, RestFrames, Kinematic Reconstruction, LHC, CMS
