Difference between revisions of "Master student Projects"

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Also for this project, computer skills and affinity with programming are required. You become a member of a small, international team with regular meetings.
 
Also for this project, computer skills and affinity with programming are required. You become a member of a small, international team with regular meetings.
  
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 3) Beyond Standard Model search in multi lepton final state </font>
 
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''' Supervisors:'''  Olya Igonkina (staf) and Joern Mahlstedt (PhD student)
 
 
 
''' Research description: '''
 
 
The Standard Model of particle physics (SM), though extremely successful, provides no insight on the mass structure of the quark and lepton families.  Compositeness models - models in which leptons and quarks are non-fundamental particles made of 'preons' - can be used to explain these features.  In such models, the 3 SM lepton families are the lowest energy bound-states of these 'preons'. Interestingly, such models imply the presence of higher energy excited states, which can be searched for at the LHC.
 
 
The goal of this project is to devise a search for these at ATLAS, in events where an excited lepton is produced along with a SM lepton. The excited lepton decay can have up to 3 SM lepton, giving a rise to 4 lepton topology.  Such a signature could significantly improve the current limits on excited lepton production.  The main focus of the project will be to determine which event observables are most sensitive to these signals by studying the various signals and the SM backgrounds.  With this project, the student would gain close familiarity with Monte Carlo generators, the standard HEP analysis tools (ROOT, C++, etc.) and with modern experimental techniques (statistical analysis, SM background estimates, etc.).
 
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 4) Beyond Standard Model: search for  lepton flavor violating decays tau-> 3 mu </font>
 
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''' Supervisors:'''  Olya Igonkina (staf) and Noam Hod (post-doc)
 
 
 
''' Research description: '''
 
 
The lepton flavor violation is a mechanism which is forbidden by Standard Model and is not observed so far in experiment. However, it could explain a large amount of matter (and lack of antimatter) found in the Universe. Such mechanism could manifest itself in decays of tau lepton into three muons. There are a lot of taus produced in ATLAS, but identification of muons close in space, in particular those that produced as part of a jet is difficult. That makes the search a challenging and interesting task.
 
 
All steps of this measurement (analysis of ATLAS data, tuning cuts on MC, understanding the background and trigger performance) are part of the master project. The programing of the code, the data analysis with ROOT and ATLAS software will be everyday tasks.
 
 
 
''' Relevant papers:'''
 
 
Review of various lepton flavor violating processes: [http://arxiv.org/pdf/arXiv:1201.5093 arXiv:1201.5093]
 
 
Plans of competing experiments Belle-2 and Super-B : [http://arxiv.org/pdf/arXiv:1109.2377 arXiv:1109.2377]
 
 
Relation between leptogenesis and lepton flavor violation : [http://arxiv.org/pdf/arXiv:0904.1182 arXiv:0904.1182]
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 5) Beyond Standard Model: search for  lepton flavor violating decays Z -> tau e </font>
 
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''' Supervisors:'''  Olya Igonkina (staf), Saminder Dhaliwal (post-doc) and Hartger Weits (PhD student)
 
 
 
''' Research description: '''
 
 
The decay of Z boson into tau and electron is another example of the lepton flavor violating process. Unlike tau->3mu this channel is easier to record and identify. At the same time, the background from Z -> tau tau and Z-> ee decays can mimic signal and reduction of background is a challenge.
 
 
All steps of this measurement (analysis of ATLAS data, tuning cuts on MC, understanding the background and trigger performance) are part of the master project. The programing of the code, the data analysis with ROOT and ATLAS software will be everyday tasks.
 
 
 
''' Relevant papers:'''
 
 
Review of various lepton flavor violating processes: [http://arxiv.org/pdf/arXiv:1201.5093 arXiv:1201.5093]
 
 
Relation between leptogenesis and lepton flavor violation : [http://arxiv.org/pdf/arXiv:0904.1182 arXiv:0904.1182]
 
  
  

Revision as of 12:42, 12 February 2015