טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentTenenbaum Katan Yaniv David
SubjectIdentification of Sleptons in the ATLAS Detector
DepartmentDepartment of Physics
Supervisor Professor Shlomit Tarem
Full Thesis textFull thesis text - English Version


Abstract

The Standard Model (SM) is an extremely successful description of nature at small scales. It supplies remarkably precise predictions up to the TeV scale.
However, the SM is a work in progress and must be extended in order to give a description of higher energy scale physics. There are many experimental hints to the existence of physics beyond the SM. At the least, the SM does not describe nature at the energy scale beyond the Planck scale, where quantum gravitational effects can no more be neglected.


One of the promising extensions of the SM, that may answer some of these issues, is "Supersymmetry" (SUSY), a space-time symmetry which connects between bosons and fermions. It predicts that every SM particle has super-partners, identical in every property, but spin.

Super-Symmetry (SUSY) theory, if confirmed will be able to solve some of the most profound problems of modern physics.

The super partners of the SM particles have yet to be discovered, which suggests they must greatly differ in mass from their SM partner. This leads to the inevitable conclusion that supersymmetry, if exists, is a broken symmetry of nature. The symmetry is expected to be spontaneously broken, hence should only fully exists above a certain energy scale and broken below that scale.

SUSY has different branches, which differ in the way SUSY is broken. Gauge Mediated Supersymmetry Breaking (GMSB) models are considered as one of the most likely supersymmetry versions.  GMSB models predict the existence of sleptons, the super-partner of SM leptons, in the energy scale reached by the LHC.


Different variants of the Theory predict symmetry breaking at different energy scales and the creation of new particles accordingly.
The High Energies of the LHC particles will allow us to discover such particles and by that validate the different models.


This work is focused on the GMSB model, which predicts Neutralino particles, heavy neutral particles that decay to pairs of Lepton and Slepton (Lepton Super-Partner). The sleptons are predicted by some models to be heavy long-lived particles, with a lifetime long enough to reach the muon detectors of ATLAS. This research will focus on the identification of such stable heavy particles as sleptons, if they are detected.

In this work we show that the first year run of the LHC should supply sufficient amount of data to confirm or exclude the existence of GMSB leptons in mass scales of up to ~130[GeV], using kinematical properties of the events in which they are produced.