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=== Projects for bachelor students in the Nikhef ATLAS group ===
 
  
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date: February 2014
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= This is the old page for 2015 bachelor projects. For the newer bachelor projects click on the link below =
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https://wiki.nikhef.nl/education/Bachelor_Projects#ATLAS =
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This is an overview with all available bachelor student projects in the Nikhef ATLAS group.  
 
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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 leaders:
 
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Stan Bentvelsen  ___ [''' E-mail: stanb_at_nikhef.nl''', Tel 020-5925140, Nikhef room H250]
 
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Paul de Jong    ______ [''' E-mail: h26_at_nikhef.nl''', Tel 020-5922087, Nikhef room H253]
 
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=== Bachelor projects in the Nikhef ATLAS group ===
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 1) Top quark spin </font>
 
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|}
 
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''' Supervisors:'''  Marcel Vreeswijk, Stan Bentvelsen (staf) and Rogier van der Geer (PhD student)
 
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''' Research description: '''
 
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In dit project wordt de spin van het top-quark bestudeerd. Recentelijk is het top-quark is bij de
 
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LHC waargenomen in botsingen tussen twee protonen, waarbij een enkel top-quark is geproduceerd
 
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door fusie van een W-boson en een b-quark. Het top-quark is daarbij uiteen gevallen, via het
 
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W-boson, in een lepton en een neutrino samen met een b-quark. Deze �single top� events zijn goed
 
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geschikt om de spin van de top-quark te achterhalen, via bepaling van een aantal hoeken in de
 
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vervals-producten.
 
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Voor deze analyse zijn verschillende methoden mogelijk, die ieder een eigen gevoeligheid hebben
 
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voor de spin van het top-quark. Tijdens dit project zullen we de verschillende methoden
 
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onderzoeken; waarbij de methoden zich onderscheiden door de hoeken vanuit verschillende Lorentz
 
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systemen te bekijken.
 
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Tijdens dit project zul je je eigen reconstructie van de botsingen maken, om daarmee te
 
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achterhalen hoe daarop het beste de spin-richting van het top-quark kan worden bepaald. Dit kan
 
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vervolgens met de ATLAS data worden vergeleken, indien de tijd dat toestaat.
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 2) Accurate measurement of the mass of the Higgs particle </font>
 
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|}
 
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''' Supervisors:'''  Ivo van Vulpen (staf) and Antonio Castelli (PhD student)
 
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''' Research description: '''
 
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The ATLAS detector allows to measure the mass of the
 
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Higgs boson, recently discovered in 2012.
 
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This measurement is a crucial test for the validity of the
 
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Standard Model, the theory that describes the interaction
 
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among elementary particles.
 
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The student will be guided through the strategy of the
 
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measurement of the Higgs boson mass from the measurement
 
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of the mass of the four leptons produced in one of its possible
 
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decay.
 
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The student's task will be to study the impact of the er-
 
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ror distribution of the four leptons mass in the final mea-
 
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surement of the Higgs mass. In order to do that he/she will
 
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learn the fundamental notions of statistical data analysis us-
 
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ing the ROOT software. He/she will then be asked to study
 
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the simulated ATLAS data to understand the main sources of
 
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uncertainty on the momentum of the reconstructed particles.
 
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Schedule
 
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week 1: Small introduction about theory and ATLAS experiment
 
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week 2: Introduction to ROOT and Higgs to four lepton event selection
 
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week 3/4: Creation and study of four lepton distribution of mass and error
 
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week 4/5: Creation and study of four lepton distribution of mass and error
 
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week 6/7: Closer look at events with large error, where does it come from?
 
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week 8/9: Closer look at events with large error, where does it come from?
 
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week 10: Presentation of the results
 
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week 11: Writing and discussion
 
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week 12: Writing and discussion
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 3) Excited leptons </font>
 
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|}
 
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''' Supervisors:'''  Olga Igonkina (staf) and Joern Mahlstedt (PhD student)
 
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''' Research description: '''
 
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The Standard Model of particle physics assumes that the world consists of leptons and quarks that
 
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are elementary particles. However, if they would be made of smaller particles, preons, that would
 
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explain the leptons and quarks mass hierarchy that we measure. Then leptons and quarks would be
 
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the lowest energetic states of preon combinations and more higher energy excited states would
 
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exist.
 
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We are looking for these excited states using the results of the ATLAS experiment.
 
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In this bachelor project new variables will be tested which can discriminate between the signal
 
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and the Standard Model background in events with at least 3 leptons.
 
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These variables can be used afterwards to increase the sensitivity of the search and to set
 
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better limits on the model parameters in case no excited leptons are discovered.
 
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During the project the student will learn to run over MC generator events with a program called
 
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Rivet, which is based on C++.
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 4) Searching for a supersymmetric partner of the top quark </font>
 
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|}
 
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''' Supervisors:'''  Paul de Jong (staf) and Priscilla Pani (PhD student)
 
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''' Research description: '''
 
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Many theories that try to solve shortcomings of the Standard Model propose that the top quark, the most massive particle in the Standard Model, may have a partner. Supersymmetry, for example, predicts a spin-0 partner of the top quark, but does not predict its mass. The ATLAS experiment at the LHC is well equipped to search for heavy new particles that may be produced in high-energy proton-proton collisions. In searches for new particles it is important to have a good understanding of all those
 
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events that might behave as our signal but are originating from already known particles
 
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(background or noise). To do so a prediction of the background is obtained by means of a Monte
 
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Carlo simulation to which certain systematic uncertainties are attributed.
 
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In this project we will try to improve the understanding of these systematic uncertainties,
 
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trying to highlight which are the physics quantities, used to discriminate the signal from the
 
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background, that are affected the most by these uncertainties. If possible we will also design a
 
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strategy to reduce the impact of these uncertainties on the background estimates in a
 
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generalised form that could be of use to all ATLAS searches.
 
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Schedule
 
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week 1/2: Introduction to theory and ATLAS experiment
 
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week 3: Introduction to ROOT
 
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week 4/5: Implementation of top squark selection criteria on simulated events and ATLAS data
 
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week 6/7: Study of the effects of variation of simulated background events
 
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week 8: Identification of physics quantities with the largest effects
 
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week 9: Designing of a strategy to minimize systematic uncertainties
 
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week 10: Presentation of the results
 
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week 11: Writing and discussion
 
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week 12: Writing and discussion
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 5) Higgs spin </font>
 
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''' Supervisors:'''  Peter Kluit (staf) and Koen Oussoren (PhD student)
 
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''' Research description: '''
 
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Het Standaard Model voorspelt dat het Higgs deeltje geen intrinsieke spin heeft. Het Higgs deeltje zou daarmee het eerste elementaire scalaire deeltje zijn. Maar is dit ook zo? Je kunt ook modellen opstellen waar het Higgs deeltje een spin 1 of spin 2 heeft.
 
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In dit project gaan we kijken hoe je deze verschillende modellen kunt onderscheiden voor het geval dat een Higgs deeltje uiteenvalt in twee W-bosonen. Daarna kijken we hoe de hoek verdelingen van de W-bosonen van de spin van de Higgs afhangen. Deze informatie kunnen we dan vergelijken met de data die door het ATLAS experiment is genomen.
 
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Bij dit project is plaats voor twee studenten. De ene student kan zich toeleggen op modulering van de hoekverdelingen van de W-bosonen. De andere student legt de nadruk op vergelijking met de experimentele gegevens.
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 6) Triple Higgs diagram  </font>
 
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''' Supervisors:'''  Stan Bentvelsen (staf), Bob van Eijk (staf) and Wouter van den Wollenberg (PhD student)
 
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''' Research description: '''
 
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Met de ontdekking van het Higgs deeltje, waar de massa is bepaald, voorspelt het minimale Standaard Model de overige eigenschappen van het Higgs deeltje. Een van de voorspellingen (die de vorm van de Higgs potentiaal vastleggen) is sterkte van het triple Higgs diagram. In de praktijk betekent dit dat een voorspelling wordt gemaakt voor de werkzame doorsnede waarbij twee Higgs deeltjes tegelijkertijd worden geproduceerd.
 
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Tijdens dit project zullen we botsingen van de LHC analyseren met twee Higgs deeltjes in de eindtoestand. We zullen simulaties van botsingen genereren en bepalen of we dit signaal met de toekomstige data van  ATLAS kunnen isoleren van de achtergrond.
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 7) Dark matter in association with top quarks  </font>
 
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''' Supervisors:'''  Paul de Jong (staf) and Priscilla Pani (PhD student)
 
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''' Research description: '''
 
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It is currently believed that ~27% of our Universe is composed by the so called Dark Matter.
 
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If this is a new particle it could be produced in proton-proton collisions at CERN�s Large
 
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Hadron Collider (LHC).
 
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In this project the student will analyse 8 TeV ATLAS data
 
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and improve the criteria that ATLAS uses to search for Dark Matter particles produced in
 
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association with top quarks. The student will focus on particular models for which the current
 
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ATLAS analyses are less sensitive and apply selection criteria designed to cut away events
 
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produced by ordinary known particles (background, noise) while retaining as much of the dark
 
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matter events as possible.
 
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{| border="1"  cellpadding="2" cellspacing="0"
 
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! style="background:#339999;" | <font color=#ffffff> 8) Hisparc data acquisitie  </font>
 
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''' Supervisors:'''  Bob van Eijk (staf) and Arne de Laat (PhD student)
 
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''' Research description: '''
 
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HiSPARC (http://www.hisparc.nl/) is a network that consists of more than 100
 
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cosmic ray detection stations in NL, UK and DK. Aim is to measure direction and energy
 
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of (very) high energy cosmic particles. Stations are operated by scientists and high-school students.
 
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Each detection stations submits data to Nikhef via internet. Monitoring and remote
 
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control runs over a VPN/VNC.
 
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Project: An event generator needs to be designed that generates 'real' data. Secondly a number of real time data analysis/data selection procedures need to be developed to optimise data acquisition.
 
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Tools: Test station at Nikhef and a database containing more than 8 years of data
 
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Programming language: C.
 

Latest revision as of 16:00, 30 January 2017

This is the old page for 2015 bachelor projects. For the newer bachelor projects click on the link below

https://wiki.nikhef.nl/education/Bachelor_Projects#ATLAS =

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