Particle Physics-abstracts

Project Title	Research Group
Measurement of Fragmentation Functions from COMPASS Data COMPASS is a fixed target experiment at CERN, Geneva that studies the nucleon spin structure using high-energy muon beams. Students are introduced to experimental particle physics, specifically the creation of hadrons in high energy scattering events. The students will analyze data taken in the last years to extract quark to hadron fragmentation functions. This internship can be combined with a visit to CERN.(analysis oriented)	F. Klein
Online Software for the COMPASS Trigger System Our group at the Physikalische Institut is responsible for the trigger system of the COMPASS experiment at CERN studying the spin structure of the nucleon. The students are introduced to experimental particle physics, specifically to real-time computer analysis of particle reactions to create trigger decisions. This internship can be combined with a visit to CERN. (analysis, software oriented)	F. Klein
Time Resolution of a Scintillation Counter with Sampled Analog Signals For a future experiment at CERN protons have to be detected with very good time resolution in large scintillator counters. The student should study in a laboratory experiment here in Bonn which time resolution can be reached using the sampling of the analog signal of a photo multiplier tube compared to the classical method using the TDC information of a discriminated analog signal. The student is also invited to participate in test measurements at CERN. (hardware, analysis oriented)	F. Klein
Application of advanced statistical methods to Higgs searches at the LHC The ATLAS Detector at the Large Hadron Collider at CERN will record collisions of high energy protons at a center-of-mass energy of 14 TeV. One of the main topics of interest is the study of electroweak symmetry breaking and the search for the Higgs boson. The Physikalische Institut plays a leading role in searching for Higgs bosons in vector boson fusion processes. Statistical tools to separate signal events from background, such as Neutral Nets, Likelihoods or Boosted Decision Trees, are employed to obtain good signal-to-background ratios. (Analysis, statistics oriented)	Wermes
Searches for the Higgs Boson in vector boson fusion events with ATLAS The ATLAS Detector at the Large Hadron Collider at CERN records collisions between high energy protons at a center-of-mass energy of 14 TeV. One of the main topics of interests is the study of electroweak symmetry breaking and the search for the Higgs boson. The Physikalische Institut plays a leading role in searching for Higgs bosons in vector boson fusion processes. Students will investigate one aspect of the signal selection or background estimation techniques. (Analysis, software oriented)	Wermes
Modern integrated Electronics for Particle Physics Experiments The Silab and the new Helmholtz Center for Detector Development at the Physikalische Institut offer research internships in either the design of integrated circuits in 180 nanometer technology or in the programming of Field Programmable Gate Arrays (FPGA) for particle physics experiments.	Wermes
Top quark reconstruction with the ATLAS Detector One of the main topics of interest at the LHC is the study of massive elementary particles such as top-quarks. The study of top properties, e.g. mass or production cross section, is an important goal of the ATLAS experiment. In this research internship reconstruction methods, such as jet energy measurements, are studied and further developed. (Analysis, software oriented)	Wermes
Reconstruction of Z-Boson decays to tau-lepton pairs as a pre-study to Higgs searches at the LHC The ATLAS Detector at the Large Hadron Collider at CERN will record collisions between high energy protons at a center-of-mass energy of 14 TeV. One of the main topics of interests is the study of electroweak symmetry breaking and the search for the Higgs boson. One important Standard Model process to calibrate various Higgs searches is the decay of the Z0 into two tau leptons. (Analysis, software oriented)	Wermes
Measurements with ATLAS-Pixel detector modules The ATLAS Detector at the Large Hadron Collider at CERN will record collisions of high energy protons at a center-of-mass energy of 14 TeV. One of the main topics of interests is the study of electroweak symmetry breaking and the search for the Higgs boson. The Physikalische Institut plays a leading role in the construction, calibration and operation of the pixel detector. Test measurements based on a ~40000 channel test module will be the focus of this internship. (Hardware, analysis oriented)	Wermes
Simulation studies for the Super-LHC Upgrade of the ATLAS Inner Detector The ATLAS Detector at the Large Hadron Collider (LHC) at CERN will record collisions between high energy protons at a center-of-mass energy of 14 TeV in the new future. One of the main topics of interest is the study of electroweak symmetry breaking and the search for the Higgs boson. Monte Carlo studies for the next experimental phase of the LHC, called Super-LHC, are currently underway to evaluate the expected performance of the tracking detector system at a luminosity of about 10^35 cm-2s-1, about ten times higher than the design luminosity of the LHC. The original ATLAS detector will not be capable to withstand such high luminosities and a new tracking system has to be designed and built. The Physikalische Institut plays a leading role in the construction and future upgrade of the ATLAS Pixel detector. The upgrade study will focus on pixel design options.	Wermes
Measurement of time resolution and detection efficiency of particle detectors This detector hardware topic focusses on time measurements with particle detectors. Traversing charged particles leave signals in the detector. The time of transgress is measured with high accuracy and high detection efficiency.	Schmieden
Monte Carlo simulation of hadronic reactions and particle tracking through detectors Monte Carlo techniques are powerful tools for evaluating the expected performance of complex particle detectors. With software programs such as GEANT 4 it is possible to simulate the full process of a particle traversing a detector and interacting with the detector material at the same time. The detector calculates on stochastical basis the deposited energy or electric charge.	Schmieden
Analysis of current data of the Crystal-Barrel experiment at ELSA The Crystal Barrel Experiment is located at the ELSA electron storage ring in Bonn. Current data from the experiments will be analyzed.	Schmieden
Research Internships at the ELSA accelerator ELSA, which is an acronym for Elektron-Stretcher-Anlage, is the accelerator of the Physikalische Institut in Bonn. Ã?ts main task is the production of a continuous electron beam of energies up to 3.5 GeV. The continuous operation mode is the main difference of ELSA to all other accelerators which usually run in a pulse beam mode.	Hillert
Top quark mass measurement with the ATLAS detector One of the most important processes at the LHC is the production of top-quarks. Being the heaviest particle observed to date, the top-quark mass is a crucial parameter for precision tests of electroweak theory and it will set a strong constrain on the mass range of the Higgs particle. In this internship the transverse momentum of the leptonic top-quark decay products will be used to measure the top-quark mass. (Analysis, software oriented)	Brock
Reconstruction of W and Z bosons as backgrounds for top-quark searches with the ATLAS detector At LHC the production of W and Z bosons play a very important role due to their high cross section. An accurate reconstruction and precise determination of their rates is mandatory to understand and separate those processes from physics processes with smaller cross section rates, like top-quark production. In this internship the reconstruction of the bosons will be studied. The observed rates will be used as an estimate for the background to top-quark signals. (Analysis, software oriented)	Brock
Search for single top in the Wt-channel with the ATLAS detector One of the ongoing topics in ATLAS is the search for single-top signals. Top quarks can be produced singly via electroweak interactions, where the top quark is produced in association with a real W boson. The cross section of the Wt-channel is negligible at the Tevatron but of considerable size at LHC energies. In this internship, different reconstruction variables will be investigated and advanced neural networks will be used to search for single-top signals. (Analysis, software oriented)	Brock
Secondary vertex tagging in ZEUS The ZEUS group offers research internships in which students analyze data from the tracking detectors of the ZEUS experiment. Students get to know a modern particle detector and learn reconstruction techniques of charged particle trajectories that ultimately lead to methods for reconstructing heavy particles with lifetimes in the picosecond range, such as b-hadrons.	Brock
Determination of trigger efficiencies In 2007 a new trigger system was installed at the COMPASS experiment at CERN. The student should help to develop an analysis method to determine the efficiency of this new system. This internship can be combined with a visit to CERN. (analysis, software oriented)	F. Klein
Studying different estimators to determine an asymmetry The COMPASS experiment at CERN studies the spin structure of the nucleon. The experimental observable is a counting rate asymmetry. The student should study different statistical estimators to extract these asymmetries and compare them in terms of their bias and efficiency. This internship can be combined with a visit to CERN. (analysis, statistics oriented)	F. Klein
Analysis of data from a time projection chamber prototype The Physikalische Institut is currently building a fully functional prototype of the time projection chamber (TPC) which is supposed to be the main tracking system of the ILC-detector. The students will participate in the development of reconstruction and analysis software, including track finding and pattern recognition.	Desch
"Nuts and bolts" of a time projection chamber Analysis of data from a time projection chamber prototype. The Physikalische Institut is currently building a fully functional prototype of the time projection chamber (TPC) which is intended to be the main tracking system of the ILC-detector. The students will conduct small research projects related to the design, building or testing of the detector.	Desch
Measuring Supersymmetry in events with tau-leptons Supersymmetry is a new fundamental symmetry of Nature that relates bosons to fermions. Experimental verification of this symmetry might be possible at the Large Hadron Collider which will start operations in 2008. There exist several scenarios of Supersymmetry in which tau leptons are abundantly produced in the decay cascades of heavier superpartners. In the project students investigate methods to determine the properties of supersymmetric particles using tau-leptons. Realistic tau reconstruction algorithms will be used in these studies.	Desch
Applications of Energy Flow methods for tau-lepton identification at the LHC Tau-leptons are short lived heavy leptons that are important for the study of yet heavier particles such as Z-Bosons, Higgs bosons or supersymmetric particles. Students learn the experimental aspects of tau reconstruction based on fundamental detector energy and momentum measurements. One new idea to conduct these studies is to use energy flow methods that optimally combine the available information from the various sub-detectors.	Desch
Crystal Barrel experiment at the Electron Stretcher facility (ELSA) The Crystal Barrel Experiment at the electron stretcher facility (ELSA) at the Physikalische Institut investigates baryon resonances created in photon nucleon interactions. Several topics are offered by groups from the PI and HISKP.	Beck, Klein, Schmieden, Thoma
Analysis of IceCube data The IceCube detector, which is embedded in the glacial ice at the geographic South Pole, is the first neutrino telescope to comprise a volume of one cubic kilometer. In the internship, using data from the online filter of the IceCube neutrino detector, the student will perform a search for neutrinos from Supernovae and Gamma-Ray Bursts.	Kowalski
New light sensors for neutrino telescopes Planning for a future large scale neutrino detector at the South Pole with sensitivity to extragalactic Supernovae has started. For this, novel photon sensors with large collecting area are being developed. In the internship, the student will optimize the performance of the sensors by means of simulation and laboratory tests.	Kowalski
Cosmic ray measurements at the South Pole Novel detection principles using geosynchrotron radiation from air- showers have been proposed that provide additional observables for the determination of the chemical composition of cosmic rays. Using simulations, the student will evaluate the potential of combining the data from different detector types at the South Pole to study cosmic rays.	Kowalski

 

Theoretical Physics Topics

 

Project Title	Research Group
Calculation of Feynman Diagrams in the Standard Model or in Supersymmetry Theoretical Particle Physics topic. Students calculate simple Feynman diagrams of the Standard model or supersymmetric models similar to the exercises in the book of Peskin and Schroeder.	Drees/Dreiner
Lattice simulations of the phase structure of U (1) gauge theory Theoretical Particle Physics topic. The discretization of quantum field theories provides a powerful tool to perform numerical studies of complex field theoretical problems.	Meißner
Extraction of the light quark mass ratios Theoretical Particle Physics topic. The ratio of u,d,s quark masses is of fundamental importance for the analysis of hadron mass spectra. The impact of the light quark masses is studied in the context of chiral perturbation theory.	Meißner/Kubis
Unitarization of scalar field theory Theoretical Particle Physics topic.	Meißner
Hadronic vacuum polarisation and the muon g-2 Theoretical Particle Physics topic. Hadronic contributions constitute the largest uncertainty in the theoretical prediction of the anomalous magnetic moment of the muon within the Standard Model. Their largest part can be described in terms of the pion form factor using dispersion theory, which - sufficiently refined - is to be compared to the high-precision data for e+ e- --> pi+ pi-.	Kubis
Calculation of the Neutralino-Nucleon Scattering Cross Section Theoretical particle physics project in the research group of Prof. Drees http://thp.uni-bonn.de/groups/drees/	Drees
Calculation of the WIMP Relic Density Theoretical particle physics project in the research group of Prof. Drees http://thp.uni-bonn.de/groups/drees/	Drees
Signals for Supersymmetry at the LHC Theoretical particle physics topic in the research group of Prof. Drees. thp.uni-bonn.de/groups/drees/	Drees