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=== Projects for Master students in the Nikhef ATLAS group ===
 
  
date: May 2014
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This page is out of date. Please go to [http://wiki.nikhef.nl/education/Master_Projects the new Master project page].
 
 
This is an overview with all available Master student projects in the Nikhef ATLAS group.  
 
 
 
 
 
If you have your own research proposal, need more detailed information on the (availability) of individual proposals or would like to discuss about other available projects in the group you are always welcome to contact either the contact person for the project and/or the Nikhef ATLAS group leader:
 
 
 
Paul de Jong    ______ [''' E-mail: h26_at_nikhef.nl''', Tel 020-5922087, Nikhef room H253]
 
 
 
 
 
For an overview of the theses written in the Nikhef ATLAS group you can look at the
 
[http://www.nikhef.nl/pub/experiments/atlaswiki/index.php/Thesis_page_ATLAS_Nikhef Nikhef ATLAS group theses page]
 
 
 
 
 
 
 
 
 
 
 
 
 
=== Master projects in the Nikhef ATLAS group ===
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 1) The polarisation of single top quarks at the LHC </font>
 
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''' Supervisors:'''  Marcel Vreeswijk (staf) and Rogier van der Geer (PhD student)
 
 
 
 
 
''' Research description: '''
 
 
 
Single top quark production is a rare process which is only in reach of the Tevatron-collider and
 
the Large Hadron Collider since the last decade.�The cross section for t-channel top quark
 
production at the� LHC allows precision measurements of the spin structure of the Wtb vertex as a
 
probe for new physics. For this research the data recorded with the ATLAS detector at 8TeV will be
 
used. The observables consist of the decay angles of the top quark from which (anomalous) couplings
 
can be extracted. Several contributions to the research are possible, which involve:
 
-selection of events and reconstruction of the observables,
 
-unfolding techniques�from measured distribution to the underlying truth distribution,
 
-which quantities can be extracted from the distribution and how do these translate to general
 
couplings?
 
 
 
For this project you need to have affinity with quantum mechanics and computer skills are needed.
 
The ROOT programme and C++ and/or Python macros are used. You become part of our research group
 
(~5 persons), we have weekly meetings with colleagues at CERN and depending on the results� -and
 
perhaps some luck-� you may co-author an (internal ATLAS) research note. The project will be soon
 
at full pace, requiring you to be flexible.
 
 
 
 
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 2) Optimizing supersymmetry searches at the 13 TeV LHC </font>
 
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''' Supervisors:'''  Paul de Jong (staf) and Ingrid Deigaard (PhD student)
 
 
 
 
 
''' Research description: '''
 
 
 
When the LHC restarts in 2015, it will do so at a center-of-mass energy of 13 TeV, significantly higher than the 8 TeV reached so far. The higher energy is very important for the searches for new massive particles in theories of physics beyond the Standard Model. Supersymmetry is a well motivated model that predicts heavy partners of quarks and gluons, these partners may be detectable with sufficient data at 13 TeV. Compared to the earlier results, the analysis at 13 TeV is challenging, and needs major reoptimization. In this master project, we will look at the trigger, at new discrimination variables, and at new models.
 
 
 
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> 6) Higgs: CP mixing and CP violation in the Higgs sector</font>
 
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''' Supervisors:''' Pamela Ferrari, Stan Bentvelsen (staf), Nikos Karasthatis (Koen Oussoren)  (PhD student).
 
 
 
 
''' Research description: '''
 
 
 
After having discovered the Higgs, the LHC experiments have determined its spin,
 
providing a proof of the spin 0 nature of the Higgs boson and indicating that a positive parity is strongly preferred.
 
Anyhow, even if it is excluded that the present Higgs boson might be a pseudoscalar,
 
the possibility that is an admixture of a CP-even and CP-odd state is far from being ruled
 
out. From present studies few hundred fb−1 at a centre of mass energy  of 14 TeV might be needed to study it
 
or narrow down significantly this possibility.
 
The presence of CP violation in the Higgs sector could  provide an
 
answer to one of the most important open questions of particle physics nowadays: the reason for the matter antimatter asymmetry
 
in the universe, which cannot be explained by the amount of CP violation observed in the quark sector of the Standard Model.
 
The project will investigate the precision with which result on CP violation will be obtained using mainly the Higgs to WW decay channel.
 
 
 
 
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 7) Higgs: WW to WW boson scattering at the LHC </font>
 
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''' Supervisors:'''  Stan Bentvelsen, Pamela Ferrari (staf),  and Rosemarie Aben (PhD student)
 
 
 
 
 
''' Research description: '''
 
 
 
Understanding the scattering of two W-bosons (WW->WW) is essential in the Standard Model. Calculations show that, in the absence of a Higgs particle, this process grows with the cm energy of the W-bosons, and ultimately become larger than unity. This is unphysical and is one of the main motivations for including the Higgs particle in the model. Now the Higgs particle has been found, it remains to be seen if the particle is responsible for restoring unitarity.
 
 
 
The measurement of this process at ATLAS  may need a few more years of data taking. But its interesting to see if the current amount of data (including the whole of 2012) reaches sensitivity to this process.
 
 
 
This project aims at the observation of the scattering of two W-bosons - in the so-called 'vector boson fusion' process. One of the first goals is to isolate events where the two W-bosons produce one Z-boson (WW->Z), which subsequent decay is measured in the ATLAS detector. In addition the study includes the effect if a Higgs particle in the process. Ultimately we have to see what is needed to isolate the WW->WW process in data.
 
 
 
 
 
 
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 8) Astroparticle physics at the LHC, from the caverns of CERN to the top of the atmosphere </font>
 
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''' Supervisors:'''  David Berge (staff) and David Salek (postdoc)
 
 
 
 
 
''' Research description: '''
 
 
 
Understanding particle acceleration up to very high energies in the Universe requires Earth-bound experimental techniques that exploit the Earth's atmosphere as detection medium. Only the sheer size of the atmosphere provides a sufficiently large sensitive area to measure the very rare highest energy particles from the cosmos as they impinge on the Earth. The idea of the atmospheric measurement is simple: a cosmic particle hitting the atmosphere is being absorbed by developing into an air shower, a spray of secondary particles that originates in the collision of the primary cosmic particle with air molecules, and successive interactions of those secondary particles in the atmosphere. Such air showers can be traced and therefore measured on Earth, providing information about the energy, type, and direction of the primary cosmic particle, by different means. Important examples of such atmospheric detection techniques include the measurement of muons with particle counters at the Earth's surface and the measurement of Cherenkov or Fluorescence light emitted during the air shower development. The connection between measured quantities like particle numbers or light intensity and original quantities like particle energy or type is in all cases inferred using simulations of particle collisions and cascades in the atmosphere.
 
 
 
The goal of this master project is to exploit data of proton collisions measured with ATLAS, an experiment at the Large Hadron Collider (LHC), the highest energy human particle collider currently operating at CERN in Geneva (Switzerland), to test and improve simulations of particle collisions in the atmosphere up to the highest known energies (a few times 10 to the power 20 eV). The student will work on ATLAS data analysis and Monte Carlo simulations of particle collisions, both for simulating proton colliding in ATLAS and cosmic-ray protons colliding with air molecules in the atmosphere. The ultimate goal is to improve Monte Carlo model predictions used for experiments like the [http://www.cta-observatory.org/ upcoming CTA] and [http://www.auger.org/ Auger].
 
 
 
 
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 9) Astroparticle physics at the LHC, going after the Dark in ATLAS </font>
 
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''' Supervisors:'''  David Berge (staff), David Salek (postdoc) and Gabriele Sabato (PhD student)
 
 
 
 
 
''' Research description: '''
 
 
 
It is currently believed that most of the matter in the Universe is a new species of so-called dark matter. This new form of matter dominates over all the known forms of matter. If the dark matter of the universe is a new particle that can be produced in proton-proton collisions at CERN's Large Hadron Collider (LHC), this new particle could couple to the recently discovered Higgs boson and could be searched for at the LHC in Higgs decays. Since a dark matter particle must be very weakly interacting it is expected that such a particle would leave the LHC detectors unseen. Looking for such invisible Higgs decays to undetectable particles is an important search for both new physics beyond the Standard Model of particle physics and dark matter. 
 
The master student will work on a search for new physics at the ATLAS experiment looking for signatures of invisibly decaying Higgs bosons, in particular in the context of dark matter. She or he will learn how to analyse high-energy particle-physics data and will focus on analysis optimisations and inter-disciplinary comparisons of the ATLAS dark matter search to direct and indirect dark matter searches on Earth and in space.
 
 
 
 
 
 
 
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! style="background:#3399ff;" | <font color=#ffffff> 10) Detector R&D: the ATLAS inner tracker upgrade </font>
 
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''' Supervisors:'''  Nigel Hessey (staff), Paul de Jong (staff)
 
 
 
 
 
''' Research description: '''
 
 
 
CERN plans to upgrade the LHC to provide a significantly higher luminosity around 2025. This will affect the ATLAS detector, and ATLAS is designing a new inner tracker in order to cope with the significant challenges associated to the high-luminosity LHC. The Nikhef ATLAS group is working on the detector layout, and designing a new silicon strip detector. In mutual discussions we can define a project that will involve either simulations, or hardware activities.
 

Latest revision as of 16:03, 30 January 2017

This page is out of date. Please go to the new Master project page.