Physics

Due to my general interest in almost everything that is or is related to physics I decided to study physics back in 2001. After about four years of broad physics education during my master degree studies mainly at Humboldt-University Berlin and Niels Bohr Institute Copenhagen, I finally decided to write my master thesis on Elementary Particle Physics at NBI.

The obviously obvious decision to continue in this field brought me to DESY (Zeuthen site) to write my Ph.D. thesis, which I defended July 12th 2010.

Currently I am a postdoc, at the Niels Bohr Institute in Copenhagen, working ...
... on searches for stable massive particles in ATLAS,
... in the ATLAS Monte Carlo production team,
... as the ATLAS SUSY Monte Carlo contact and
... on various outreach projects.

Institutes I came across for more than a handful of days.

ATLAS LEGO model

In fall 2011, I have designed a model of the ATLAS experiment made entirely of LEGO bricks.
It illustrates all details, from the muon and magnet system to the innermost pixel detector and will hopefully be a great eye-catcher for all generations. Here's some key features:

• about 9500 pieces
• roughly 1:50 in scale
  (close to scale with the LEGO man)
• material cost of about 2000 Euros
  (payed by the high energy physics group at the Niels Bohr Institute)
• about 1 m x 0.5 m x 0.5 m in size
• approximately 33 hours construction time
  (spread out over several weekends and after hours)
• around 48 hours to build the 3D model
  (a one-timer though)

As a follow up to the 1:50 model, I also designed a smaller and cheaper miniature model in LEGO bricks.
Though it does not illustrate all details, the key features of ATLAS are visible. Here's some key features:

• 560 pieces
• roughly 1:2000 in scale
• material cost of about 75 Euros
• about 22 cm x 11 cm x 11 cm in size
• approximately 90 minutes construction time
• around 7 hours to build the 3D model
  (a one-timer though)

More details, images, videos, a media coverage overview and the video construction manual can be found at http://atlas-model.mehlhase.info/!

Thanks a lot to Jørgen Beck Hansen and Peter Rosendahl for some initial thoughts on the model,
to the NBI workshop at Rockefeller for the showcase and to the high energy physics group in general for financing this idea.

LEGO is a trademark of the LEGO Group.

Publications

Below I compiled a selection of publications with personal involvement.
A more complete list of publications as member of the ATLAS collaboration can be found on INSPIRE.

• "Searches for heavy long-lived Sleptons and R-hadrons with the ATLAS detector"
  ATLAS proceedings (ATL-PHYS-PROC-2013-005) - January 10th 2013
  ATLAS poster (ATL-PHYS-SLIDE-2012-764) at the Hadron Collider Physics Symposium 2012, Kyoto/Japan - November 15th 2012
• "Searches for Heavy Long-Lived Sleptons and R-hadrons with the ATLAS detector
  in pp collisions at Sqrt(s) = 7 TeV"
  paper published in Phys. Lett. B Vol. 720, Iss. 4-5, 277-308 - March 26th 2013
• "Search for long-lived massive particles with the ATLAS detector"
  talk on behalf of the ATLAS collaborations (ATL-PHYS-SLIDE-2012-727) - August 16th 2012
• "Searches for Heavy Long-Lived Sleptons and R-hadrons with the ATLAS detector
  in pp collisions at Sqrt(s) = 7 TeV"
  ATLAS conf note (ATLAS-CONF-2012-075) - July 6th 2012
• "Search for charged long-lived particles with the ATLAS Experiment at the LHC"
  internal ATLAS note (ATL-PHYS-INT-2012-011) - March 25th 2012
• "A Summary of Thermal Measurements from the Pixel Commissioning Programm"
  internal ATLAS note (ATL-INDET-INT-2011-003) - April 20th 2011
• "The German National Analysis Facility as a tool for ATLAS analyses"
  proceedings (ATL-SOFT-PROC-2011-009) to be published in J. Phys.: Conf. Ser in 2011 - January 13th 2011
  ATLAS poster (ATL-SOFT-SLIDE-2010-356) - October 8th 2010
• "ATLAS Insertable B-Layer Technical Design Report"
  ATLAS technical design report (ATLAS-TDR-019) - October 6th 2010
• "Development of a Data-Driven Algorithm to Determine the W+Jets Background in tT Events in ATLAS"
  Ph.D. thesis - July 12th 2010
• "Commissioning of the ATLAS Pixel Optical Readout Link"
  internal ATLAS note (ATL-INDET-INT-2010-012) - June 15th 2010
• "Prospects for Top Physics at the start-up LHC"
  talk on behalf of the ATLAS and CMS collaborations (ATL-PHYS-SLIDE-2009-275)
  at the 22nd International Workshop on Weak Interactions and Neutrinos, Perugia/Italy - September 15th 2009
• "Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics"
  book published as ISBN 978-92-9083-321-5 - December 2008
• "Re-evaluation of the LHC potential for the measurement of mW"
  paper published in Eur.Phys.J.C57:627-651,2008 - May 14th 2008
• "Electron Identification with the TRT and the W Boson Mass Measurement at ATLAS"
  Master Thesis - February 23rd 2007
• "A probability based approach to PID in the TRT detector of ATLAS"
  internal ATLAS communication (ATL-COM-INDET-2006-017) - October 7th 2006

Students/Teaching

• "Applied Statistics"
  exercise tutor and exchange lecturer (winter semester 2012)
  Niels Bohr Institute
• "Applied Statistics"
  exercise tutor and exchange lecturer (winter semester 2011)
  Niels Bohr Institute
• Kamilla Trans and Samuel Stokholm Baxter
  academic advisor for their first year project (spring 2011)
  project title: "Karakteristik af scintillatorer til DUKS projektet" (Characterisation of scintillators for the DUKS project)
  Niels Bohr Institute
• Karina Bzheumikhova
  secondary supervision of her bachelor project (2009)
  DESY/Humboldt Universität zu Berlin
• Clemens Lange
  secondary supervision of his summer student project (2007) and master thesis (2008/09)
  thesis title: "Studies of Single Top Production in Proton-Proton Collisions with the ATLAS Experiment"
  DESY/Humboldt Universität zu Berlin
• "Detektoren in der Elementarteilchenphysik" (Detectors in elementary particle physics)
  exercise tutor and exchange lecturer (summer semester 2007)
  Humboldt Universität zu Berlin

Outreach

To convince more and more people of the beauty of physics and the world in general, I got myself involved in several outreach activities.
Some of the projects / events, where I took part in the organisation and/or realisation, are listed below.

• "Kulturnatten"
  organising the particle physics exhibition at the Niels Bohr Institute, University of Copenhagen, Copenhagen (Oct 11th 2013)
• ATLAS model construction at University of Bergen
  building and advertising the ATLAS model and the physics at the University of Bergen, Bergen (Aug 7th-10th 2013)
• "Passeport Big Bang"
  taking part in the organisation of one of the stations during the inauguration at CERN, Geneva (Jun 2nd 2013)
• "Kulturnatten"
  organising the particle physics exhibition at the Niels Bohr Institute, University of Copenhagen, Copenhagen (Oct 12th 2012)
• ATLAS model construction at CERN
  building and advertising the ATLAS model at CERN (Sep 26th/27th 2012)
• "Public hangout at ICHEP"
  taking part in a joined public ATLAS and CMS Q'n'A Google hangout, Melbourne (Jul 7th 2012)
• "LHC exhibition at Melbourne Planetarium"
  taking part in the organisation, Museum Victoria, Melbourne (Jun/Jul 2012)
• "Tag der Weltmaschine - Science Slam"
  participant in the science slam, Urania Berlin, Berlin (Dec 23rd 2011)
• "ATLAS LEGO model"
  designing and building a 1:50 LEGO model of the ATLAS detector (Oct/Nov 2011)
• "Kulturnatten"
  Guide at Niels Bohr Institute, University of Copenhagen, Copenhagen (Oct 14th 2011)
• "Big Bang"
  Guide in the "Big Bang" exhibition, Experimentarium, Copenhagen (Jan 11th 2011)
• "Lange Nacht der Wissenschaften in Berlin und Potsdam"
  Guide in the Physics Institute, Humboldt University, Berlin (Jun 5th 2010)
• "Tag der Wissenschaften am Marie-Curie-Gymnasium Wittenberge"
  Talk about the phyics and technique(s) of the LHC, Marie-Curie-Gymnasium, Wittenberge (Nov 13th 2009)
• "MINT-Experimentier-Camp 2009 der Stiftung Deutsche Wirtschaft e.V."
  Guide for teachers and students in the exhibition, DESY, Zeuthen (Nov 6th 2009)
• Official CERN Guide
  (ATLAS, CAST, CMS, Computing Center, LEIR/LEAR, LHCb, Linac2, SM18)
  Guide to various CERN experiments, CERN, Geneva (2009)
• "Weltmaschine"
  Guide in the exhibition, Subway station Bundestag, Berlin (Nov 1st-2nd 2008)
• "LHC-Startup BMBF Press Conference"
  Press Conference, Federal Ministry of Education and Research, Berlin (Sep 10th 2008)
• "Physik zum Frühstück"
  Q&A about physics, DESY, Zeuthen (Jul 13th 2008)
• "Lange Nacht der Wissenschaften in Berlin und Potsdam"
  Guide in the "LHC-Train", S41 LHC-Train, Berlin (Jun 14th 2008)
• "CERN Open Day 2008"
  ATLAS-Guide, CERN, Geneva (Apr 6th 2008)
• "Lange Nacht der Wissenschaften in Berlin und Potsdam"
  Guide in the Physics Institute, Humboldt University, Berlin (Jun 9th 2007)
• "Kulturnatten"
  Guide at Niels Bohr Institute, University of Copenhagen, Copenhagen (Oct 13th 2006)

Travelling

My little sum up of scheduled and realised trips in the name of science.

• Lepton Photon 2013
  Menlo Park, United States of America (Jun 24th-29th 2013)
• Meetings and Passeport Big Bang inauguration at CERN
  Geneva, Switzerland (May 31st - Jun 3rd 2013)
• Meetings and ATLAS Guide training at CERN
  Geneva, Switzerland (Apr 9th-11th 2013)
• Hadron Collider Physics Symposium 2012
  Kyoto, Japan (Nov 12th-16th 2012)
• ATLAS model construction at CERN
  Geneva, Switzerland (Sep 26th - Oct 1st 2012)
• 20th International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY2012)
  Beijing, China (Aug 13th-18th 2012)
• 36th International Conference on High Energy Physics (ICHEP 2012)
  & LHC/ATLAS exhibition at Melbourne Planetarium
  Melbourne, Australia (Jun 28th - Jul 18th 2012)
• Tag der Weltmaschine - Science Slam
  Berlin, Germany (Nov 23rd 2011)
• Hadron Collider Physics Symposium 2011
  Paris, France (Nov 14th-18th 2011)
• SMP workshop, Israel Institute of Technology
  Haifa, Isreal (Oct 28th - Nov 4th 2011)
• Annual meeting of the Danish Physical Society
  Nyborg, Denmark (Jun 21st/22nd 2011)
• Lundbeck ATLAS Group Workshop
  Athens, Greece (Jun 14th-19th 2011)
• CMOS Introduction, Institut de Recherches Subatomiques
  Strasbourg, France (Jun 12th-14th 2011)
• ATLAS LLP Workshop, La Sapienza
  Rome, Italy (Apr 7th/8th 2011)
• SUSY Meeting / Pixel Thermal Note Working Meeting, CERN
  Geneva, Switzerland (Jan 23rd-28th 2011)
• 18th International Conference on Computing in High Energy and Nuclear Physics (CHEP 2010)
  Taipei, Taiwan (Oct 18th-22nd 2010)
• Frühjahrstagung der Deutschen Physikalischen Gesellschaft
  Bonn, Germany (Mar 17th-19th 2010)
• Pixel Thermal Note Working Meeting, CERN
  Geneva, Switzerland (Jan 18th-21st 2010)
• ATLAS-D Meeting
  Bonn, Germany (Sep 23rd-25th 2009)
• 22nd International Workshop on Weak Interactions and Neutrinos
  Perugia, Italy (Sep 13th-18th 2009)
• Work in Pixel Group & Shifts, CERN
  Geneva, Switzerland (Apr 1st - Jul 7th 2009)
• ID & ATLAS Week, CERN
  Geneva, Switzerland (Feb 8th-17th 2009)
• Weltmaschine Exhibition
  Berlin, Germany (Nov 1st/2nd 2008)
• Work in Pixel Group & Shifts, CERN
  Geneva, Switzerland (Sep 28th - Dec 20th 2008)
• ATLAS-D Meeting
  Munich, Germany (Sep 17th-19th 2008)
• 2008 Hadron Collider Physics Summer School, Fermilab
  Chicago, United States of America (Aug 12th-22nd 2008)
• National Analysis Facility and Full Dress Rehearsal Tutorial, DESY
  Hamburg, Germany (May 13th-15th 2008)
• CERN Open Day and ATLAS Week, CERN
  Geneva, Switzerland (Apr 3rd-9th 2008)
• Frühjahrstagung der Deutschen Physikalischen Gesellschaft
  Freiburg, Germany (Mar 3rd-7th 2008)
• LHC-D Top Meeting
  Bad Honnef, Germany (Feb 8th-9th 2008)
• 'Physics at the Terascale' - Kick Off Workshop at DESY
  Hamburg, Germany (Dec 4th-6th 2007)
• EventView Tutorial by Amir Farbin, DESY
  Hamburg, Germany (Nov 12th/13th 2007)
• ATLAS Trigger & Physics week, CERN
  Geneva, Switzerland (Nov 3rd-11th 2007)
• Autumn School for Particle Physics
  Maria Laach, Germany (Sep 4th-14th 2007)
• Inner Detector week & Top working meeting, CERN
  Geneva, Switzerland (Jun 18th - Jul 7th 2007)
• ATLAS Trigger & Physics week, CERN
  Geneva, Switzerland (Oct 30th - Nov 3rd 2006)
• European Summer University
  Strasbourg, France (Jul 3rd-12th 2006)
• Annual meeting of the Danish Physical Society
  Nyborg, Denmark (Jun 1st/2nd 2006)
• Inner Detector week, CERN
  Geneva, Switzerland (Sep 26th-30th 2005)
• Summer Student Lectures/Project, CERN
  Geneva, Switzerland (Jul 5th - Sep 18th 2005)
• Annual meeting of the Danish Physical Society
  Nyborg, Denmark (Jun 2nd/3rd 2005)

Ph.D. thesis

In 2007 I started working on my Ph.D. thesis in elementary particle physics at DESY in Zeuthen and Humboldt-University in Berlin.

I was mainly working on event-selection (trigger) analyses as well as a new/modified approach to estimate backgrounds to top-quark events in a data-driven manner at the ATLAS experiment at CERN. Besides that I worked on Detector-Control-System software for the Pixel Detector of ATLAS and performed studies on the thermal performance of this device.

This all ended up in a thesis titled: "Development of a Data-Driven Algorithm to Determine the W+Jets Background in Top-Antitop Events in ATLAS", which I handed in end of May 2010.

On July 12th 2010 I defended my thesis in a public disputation and finally got my diploma in September 2010.

Full text PDF of my Ph.D. thesis.

Master thesis

Roughly 6.3 years ago, on Februar 23rd 2007, I defended my master thesis in a public colloquium at NBI and thereby recieved the degree Master of Science from the University of Copenhagen (DK).

For my thesis entitled: "Electron Identification with the TRT and the W Boson Mass Measurement at ATLAS", I worked on methods and analyses connected to the electron identification in one of the sub-detectors of the ATLAS experiment, called Transition Radiation Tracker (TRT). And the potential capabilities of the ATLAS experiment to measure the mass of the W boson. For the latter I was mainly trying to characterise the theoretical uncertainties introduced by virtual and real QED FSR.

Full text PDF of my master thesis.

Master studies

Just for completeness I put up a little table with my course plan for my MSc degree ...

Winter semester '06/'07
Master thesis (supervisor: Dr. Troels Petersen, advisor: Prof. John Renner Hansen)
Summer school '06
European Summer University "Particles and the Universe" in Strasbourg (FR)
Summer semester '06
Master thesis (supervisor: Dr. Troels Petersen, advisor: Prof. John Renner Hansen)
Winter semester '05/'06
Introduction to the Standard Model of particle Physics (Dr. W. Bietenholz)
X-ray crystal optics (Prof. R. Köhler)
Introduction to astrophysics (Prof. Kolanoski)
Seminar in experimental physics (Prof. Fussmann, Prof. Kolanoski, Prof. Lohse, Prof. Pavel)
Laboratory work in the surface science group (Dr. M. Busch, Prof. Winter)
Summer school '05
CERN Summer-Student Lectures '05 I designed the 2005 Summer Student t-shirt front :) See it here!
"Particle identification at TRT/ATLAS"-project at CERN in the high energy physics-group of the Niels Bohr Institutes in Copenhagen (DK) (Dr. T. Petersen, Prof. J.D. Hansen)
Summer semester '05
Strong interaction in theory and experiment (Prof. F. Sannino, I. Bearden)
Neutron scattering in theory, simulation and experiment incl. experimental week at the Paul Scherer Institute (PSI) in Villingen, CH (Dr. K. Lefmann)
"Particle identification at TRT/ATLAS"-project at CERN in the high energy physics-group of the Niels Bohr Institutes in Copenhagen (DK) (Dr. T. Petersen, Prof. J.D. Hansen)
Danish module 3 (Kamma)
Winter semester '04/'05
Physics and chemistry of nanostructures (T. Björnholm, A.-P. Jauho, S. Helvig, O. Södermann, L. Montelius, S. Mørup, A. Menin, K. Flensberg, a.o.)
Biophysics of non-equilibrium processes in biology and evolution (Dr. Heimburg)
Many body physics (Prof. K. Flensberg)
Experimental methods in high energy physics (Prof. J.D. Hansen)
Elementary particle physics (Prof. P.H. Damgaard)
Danish module 2 (Elinborg)
Summer school '04
Danish module 1 (Jeppe)
Summer semester '04
Statistical physics and quantum statistics (Prof. Sokolov)
Introduction to plasma physics (Prof. Fußmann)
Introduction to surface physics (Prof. Winter)
Applied optics and holography (Dr. Wernicke)
Advanced laboratory course
Winter semester '03/'04
Quantum theory II (Prof. Ebert)
Structure of matter A: Atomic and molecular physics (Prof. Rabe)
Structure of matter B: Solid state physics (Prof. Manzke)
Advanced laboratory course
Summer semester '03
Quantum theory I Quantum mechanics, experimental introduction to quantum physics (Prof. Ebert / Prof. Köhler)
Thermodynamics (Prof. Lüst)
English for students of natural sciences
Winter semester '02/'03
Physics III Electrodynamics, wave optics (Prof. Keiper / Prof. Köhler)
Analysis III (Prof. Bank)
Complex analysis (Dr. Meyer)
Applied computer science I (Prof. Coy)
Basic laboratory course III Electricity, magnetism, geometrical and wave optics
Summer semester '02
Physics II Analytical mechanics, electro and magneto statics, geometrical optics (Prof. Keiper / Prof. Köhler)
Analysis II (Prof. Bank)
Linear algebra (Dr. Tuschik)
Physical chemistry with laboratory course (Prof. Rademann)
Basic laboratory course II Mechanics, vibrations, thermodynamics
Winter semester '01/'02
Physics I Mathematical tools, classical mechanics (Prof. Keiper / Prof. Köhler)
Analysis I (Prof. Bank)
Basic laboratory course I Measurement methods, error calculation, critical result assessment