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Thesis Opportunities

Master Thesis

We have open positions for master students to write their thesis in various research fields in high energy physics. The topics and the details are listed below.

  • Requirements:

    A good knowledge of particle physics is essential and at least basic programming skills are required. Solid programming can be very useful. The master thesis should be finished within 1 year.

    The students should first choose a topic and then perfom a detailed analysis on the specified subject. The results of the studies will then be documented in the form of a master thesis. During their 1-year period, the master students are encouraged to take part in tutoring the physics lectures.

  • Available Topics:
    • STYX Experiment:

      The STYX experiment is part of the Master lab. course. It uses straw-tube detectors from the ZEUS experiment to measure the properties of cosmic rays. These are the same basic detector elements as those used in the ATLAS TRT. The detector also allows students to become familiar with operating many aspects of a particle-physics detector from testing to calibration and track reconstruction. New ideas for the tracking include the use of a Hough transformation for track finding. Studies and improvements to the setup of the experiment include implementing a new readout board, which would allow measurements over a larger area, a redesign of the powering and readout connections and improvements in the calibration tools.

    • Serial powering (possibility of extending this topic for a PhD):
      The inner detector tracking system has to be completely renovated for the High Luminosity LHC upgrade in 2023. The new tracker (Inner Tracker System, iTk), based purely on silicon detectors, will have higher granularity to cope with the increased occupancy and larger pile-up with respect to the current conditions. In order to provide power, data and control signals for each pixel detector module, a huge number of services is required. This fact introduces a large amount of dead material in the tracker acceptance, impacting the performance of the outer detectors. Serial powering is the proposed alternatives to minimise the number of cables needed to operate the detector and thus dramatically reduce the material budget of the inner tracker. In the serial powering concept the power is supplied to the modules with a low current flowing in series from one module to its neighbour. The existing working prototype will be scaled and the final concept will be implemented.
    • Particle flow algorithm:
      The particle flow algorithm in ATLAS has been developed to improve the energy resolution of hadronic objects (jets, taus, missing transverse energy), which are a key ingredient for many physics analyses. The idea of the particle flow algorithm is to replace the energy deposited by the charged particles in the calorimeters by the momentum determined by the tracking system; exploiting the fact that the tracker has better resolution than the calorimeter for low transverse momentum. The studies performed using Run I data have shown improvements in the resolution of jets such that this technique appears advantageous. Now, the Run 2 is just starting and the coming data is a perfect scenario to exploit the benefits of this novel algorithm.
    • Measurement of the single top quark production in association with a Z boson:

      Single top-quark production has been measured for the first time by the Tevatron experiments CDF and D0. The LHC experiments ATAS and CMS were able to observe the production with much less data, thanks to the larger cross-section at higher energies. The coupling between a top quark and the Higgs boson is a key measurement that is planned to be made with the data from LHC Run 2. If the Higgs boson coupling is exactly as predicted in the Standard Model, the production of a Higgs boson in association with a single top quark is expected to be very small. However, non-standard couplings could enhance the cross-section significantly. As a first step towards a measurement of tH production, tZ production can be studied. Such a measurement allows the techniques to be developed and optimised for a later search for tH production.

    • Top-quark production via strong Flavour Changing Neutral Current (FCNC):

      The decay of the top quark to other quark flavours mediated by neutral bosons, so called FCNC, is forbidden at tree level and highly suppressed at higher orders. However, some extensions of the SM (two-Higgs-doublet models, minimal supersymmetric SM, etc.) increase the FCNC production rates and make them detectable at the LHC. FCNC analyses have been already performed in our group using the data collected with the ATLAS detector in at centre-of-mass energies, √ s = 7 and 8 TeV. The studies were made by searching for anomalous single top-quark production (qg ➝ t). As no FCNC signal has been observed in Run 1, an upper limit has been set. Run 2 is an optimal scenario for continuing these searches with much more data and higher energies.

Bachelor Theses

 

Motivated students have the opportunity to join the group and work in high energy elementary particle physics in the context of an international collaboration like ATLAS or ZEUS.

  • Requirements:

    The topic of the bachelor thesis will be assigned when at least 90 points have been collected in the bachelor studies. It is possible to begin the bachelor thesis already in the 5th semester. The bachelor thesis should be finished within a maximum of 4 months.

    Recommended knowledge:

    Successful participation in the courses "Einführung in die EDV", "Numerische Methoden der Physik" and "Physik V: Kerne und Teilchen".

  • Available Topics:
    More detailed information about these topics can be found in the Master thesis section.
    • STYX Experiment
    • Serial powering
  • Contents:

    The work gives interested students the opportunity to gain practical experience in our research group and to learn experimental techniques used in particle physics.

    Before starting the bachelor thesis an introduction to the research topics of the group is given. Once the thesis topic is chosen you will learn the handling of the commonly used software as well as programming languages like C++. With the experience gained in this field, the student should be able to apply data analysis methods for studying high energy particle interactions. The last part of the bachelor thesis consists in presenting the results to the group.

 

Internships

(→ Reference)

Information at Mrs. Fürstenberg, Room 100, Physikalisches Institut

 

materiebausteine_ger.jpgStudents (6th semester and above) who already attended the Lecture on Particle Physics and the Advanced Laboratory Course have the opportunity to join the group and work full time during three or four weeks on high energy elementary particle physics and get acquainted with the research topics and analysis methods used in the group.

At the beginning of the internship, an introduction to the research topics of the group is given. The group members will also explain the used software. Then the student should work on an analysis under the support and advise of the group. With the experience gained in the topic, the student should be able use data analysis methods to study high energy particle interactions. Some time for the investigation of own questions related to the research topic will also be given. The last part of the internship consists in the presentation of the results to the group.


 


 

 

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