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School of Physical and Chemical Sciences

Dr Ulla Blumenschein

Ulla

Senior Lecturer in Particle Physics

Email: u.blumenschein@qmul.ac.uk
Telephone: 020 7882 6967
Room Number: G. O. Jones Building, Room 407
Office Hours: Tuesdays, 9-10 am, Thursdays, 1-2pm

Profile

Qualifications:

  • Diploma in Biology (corresponds to an MSci), Mainz University
  • PhD in Physics, Freiburg University
  • Habilitation (higher education qualification), Goettingen University

Research Expertise:

  • Plant biology (physiological indicators of forest damage)
  • Particle detectors, Calorimetry: Construction of a PbF2 calorimeter and commissioning and operation of a steel-scintillator sampling calorimeter, calibration and monitoring readout, DCS and monitoring software
  • Particle detectors, Trigger: Monitoring, simulation, electron/photon trigger development, operation
  • Particle physics data analysis: QCD and EWK physics: analysis management and review, associated Z/W+jets production; Higgs physics: Yukawa coupling to fermions; Beyond-Standard-Model physics: Search for Supersymmetry (gauginos, leptons), search for heavy charged and neutral Higgs bosons (2HDM and other models), search for heave gauge bosons (Z')
  • Big data, software: Fortran, C++, python, data skimming and slimming management, analysis software management 

Academic positions:

Starting from the academic year 2017/18, I have been PhD progression tutor of the Particle Physics department (PPRC) at the School of Physics and Astronomy. I am also the STFC contact at the School of Physics and Astronomy for matters related to PhD scholarships and the contact for the Graduate training network GRADnet of the South East Physics network SEPnet. I am also the contact for the NExT Institute.

Starting from the academic year 2020/21 I have been deputy exam board chair and acting exam board chair of the School of Physics and Astronomy.  In this role, I have managed the exam paper review and the execution of the semester A and the semester B main exams and of the summer LSR exams, dealing with plagiarism cases, interacted with external examiners and chaired several UG SEB meetings.

I have also been a member of the task forces for the development and implementation of a blended teaching approach at the School of Physics and Astronomy in the academic years 2020/21 and 2021/22. In this functionality, I have worked on the implementation of new assessment strategies and a hybrid classroom approach.

I am deputy leader of the PPRC ATLAS Level-1 calorimeter trigger group.  

Brief research summary

I have dedicated my physics research to High-energy physics at particle colliders.

During my UG studies at Mainz university, I participated in the construction of the A4 calorimeter at the MAMI accelerator at Mainz University, and in the construction of the Compass experiment at the SPS at CERN in Switzerland.

During my MSc in Mainz, I developed and performed a search for supersymmetric particles, sleptons, indirect production and through gaugino cascades, at the electron-positron collider at LEP. I managed to derive the first lower limit on the selectron mass which was independent of the mass difference to the lightest supersymmetric particle.

For my PhD with Freiburg university, I continued searching for supersymmetry: I established the first search for associated chargino-neutralino production in tri-lepton final states at the D0 experiment at the proton-antiproton collider Tevatron in Illinois. I was also responsible for the calorimeter control system, developed new triggers for isolated electrons and photons and designed the electron/photon trigger suite.

After the PhD, I moved to the ATLAS experiment as a postdoc with  IFAE Barcelona, where I managed the online and offline commissioning and the first operation of the ATLAS Tile calorimeter. I was also responsible for the analogue calibration and monitoring readout system. I developed the first feasibility study for in-situ jet calibration.

As a research assistant with Goettingen University, during LHC Run1, I developed the first measurement of associated Z+jets production and later managed all measurements with W and Z bosons. I also searched for Higgs bosons in decays to 2 tau-leptons. I have developed trigger monitoring software and participated in the operation of the ATLAS detector, as a calorimeter, trigger and monitoring expert and as a shift leader. I was appointed ATLAS analysis software coordinator at the critical phase where we reorganized the software for Run-2.

In LHC Run2, I managed all ATLAS measurements of QCD and electroweak processes, a position where I reported directly to the Physics Coordination. I also published the first Z+jets cross-section measurement at cms energies of 13TeV and established the Higgs-Yukawa coupling to fermions, using Higgs decays to two tau-leptons. I also worked on tau identification and the reconstruction of di-tau final states. I participated in the operation of the ATLAS detector as ARC shift leader. During LHC Run2, I  moved to PPRC at QMUL.

I am currently performing measurements of the production of Z bosons in association with high-energetic jets and in association with charm and bottom quarks, both key backgrounds to Higgs and BSM searches. I am also searching for charged and neutral heavy Higgs bosons arising from 2HDM models and for new heavy gauge bosons, in decays to Z or W boson and light Higgs boson. 

Teaching

UG teaching:

2008-2016:

  • Nuclear and Particle Physics (BSc/MSc, module-assistant)
  • Physics of the Higgs boson (BSc/MSc, module organizer)
  • Statistical data analysis (BSc/MSc, module organizer)
  • Physics of the atom-shell (BSc, module-assistant)
  • Physics laboratory (BSc, module-assistant)
  • Electronics laboratory (BSc/MSc, module-assistant)
  • Physics for chemists and engineers (BSc, module organizer)

2017/18:

  • SPA4601 Professional Skills for Scientists (1st year, Semester A, modul co-organizer)
  • SPA4321 Introduction to C++ (1st year, Semester B, modul organizer)
  • SPA7029U/P Collider Physics (4th year, Semester B, deputy module organizer)

2018/19:

  • SPA4601 Professional Skills for Scientists (1st year, Semester A, module co-organizer)
  • SPA5201 Physics Laboratory (Semester B, module co-organizer)
  • SPA7029U/P Collider Physics (4th year, Semester B, deputy module organizer)

2019/20:

  • SPA4601 Professional Skills for Scientists (1st year, Semester A, module organizer)
  • SPA6306 Elementary Particpe Physics  (3rd year, Semester A, module  organizer)
  • SPA7029U/P Collider Physics (4th year, Semester B, deputy module organizer)

2020/21:

  • SPA6306 Elementary Particle Physics (3rd year, Semester B, module organizer)
  • SPA4122 Mathematical techniques II (1st year, Semester B, module-assistant)

2021/22:

  • SPA6306 Elementary Particle Physics (3rd year, Semester B, module organizer)
  • SPA4122 Mathematical techniques II (1st year, Semester B, module-assistant)

Teaching development:

From 2008-2016, I have developed the lecture Physics of the Higgs boson and introduced two new experiments in the advanced laboratory course. I have also developed the course work for the new course Nuclear and Particle Physics.

At  QMUL, I have co-developed the course SPA4601 Professional Skills for Scientists and significantly upgraded the course SPA6306 Elementary Particpe Physics. 

PG teaching:

PhD Students:

  • Jacob Oliver: Production of Z bosons in association with bottom and charm quarks at ATLAS
  • Tong Qiu: Search for a massive Higgs boson with the ATLAS detector at the LHC experiment
  • Arran Freegard: Higher-order QCD & EW corrections for high-energy V+jets production

PhD examination:

  • 5 PhD vivas as an internal examiner at QMUL
  • 5 PhD vivas  as external examiner

PhD Projects:

BSc and MSc Projects:

  • Regularized unfolding in hadron collider measurements
  • Associated production of Z bosons with c or b quarks
  • Using Machine Learning  to improve the search for new heavy Higgs bosons
  • Review of 2-Higgs-Doublet models and experimental tests at colliders
  • ATLAS Level-1 calorimeter trigger upgrade: simulation and monitoring

 

Research

Research Interests:

I am interested in the Fundamental forces in nature.  By recreating conditions of the early universe in powerful synchrotrons like the Large Hadron Collider (LHC), we aim to improve our understanding of the various forces with the hope to eventually be able to describe them in a unified theory.

The precision of the theoretical description of interactions in high-energy collisions has increased dramatically over the past years, prompting us to test them at a high precision level, with the option to find signs for new physics in deviations from the current models. In the ATLAS experiment, I have been investigating in particular the Strong Force by measuring processes where jets of hadrons are produced in association with the massive carriers of the weak force (JHEP 07 (2013) 032 Eur. Phys. J. C77 (2017) 361).  Currently, I am focusing on two challenging classes of these interactions Processes with a Z boson and bottom or charm quarks in the final state and processes where a collinear Z boson is radiated by a high-energetic quark in the final state. Both processes can mimic important new physics interactions, and must hence be modelled with high precision.  

In our Standard Model, the breaking of Electroweak symmetry by the Higgs field leads to massive force carriers and at least one Higgs boson, which was discovered at the LHC in 2012.  I have contributed heavily  to establish the Yukawa coupling of the Higgs to fermions, which is crucial to generate the fermion masses (JHEP 04 (2015) 117plain 

Models which go beyond that and predict two Higgs doublets (2HDM)  with five massive Higgs bosons, could help understand why we have more matter than anti-matter in our universe. In such a model, a heavy new Higgs boson could be produced at the LHC and decay into the light Higgs and a Z boson. I am searching for such processes in final states with leptons and b-quarks.

Publications

Selected publications:

ALEPH experiment:

  • A. Heister et al., [ALEPH Collaboration], Absolute Lower Limits on the Masses of Selectrons and Sneutrinos in the MSSM, Phys. Lett. B 544 (2002) 73-88

D0 experiment:

  • V. M. Abazov et al. [D0 Collaboration], Search for supersymmetry via associated production of charginos and neutralinos in final states with three leptons, Phys. Rev. Lett. 95 (2005) 151805.

ATLAS experiment, LHC Run1

  • K. J. Anderson et al., A Mobile Data Acquisition System, JINST 2, P07002 (2007).
  • G. Aad et al. [ATLAS Collaboration], Measurement of the Z to tau cross-section with the ATLAS detector, Phys. Rev. D 84, 112006 (2011).
  • G. Aad et al. [ATLAS Collaboration], Measurement of the production cross-section for Z/gamma* in association with jets in pp collisions at √s = 7 TeV with the ATLAS detector, Phys. Rev. D 85 (2012) 032009.
  • G. Aad et al. [ATLAS Collaboration], Search for the Standard Model Higgs boson in the H to tau+ tau- decay mode in √s = 7 TeV pp collisions with ATLAS , JHEP {09} (2012) 070.
  • G. Aad et al. [ATLAS Collaboration], Measurement of the production cross-section of jets in association with a Z boson in pp collisions at √s = 7 TeV with the ATLAS detector, JHEP 07(2013) 032.
  • G. Aad et al.[ATLAS Collaboration], Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector, JHEP 04 (2015) 117.
  • G.Aad et al. [ATLAS Collaboration], Identification and energy calibration of hadronically decaying tau leptons with the ATLAS experiment in pp collisions at √s = 8 TeV, Eur. Phys. J. C (2015).

ATLAS experiment, LHC Run2

  • G. Aad et al. [ATLAS Collaboration], Measurement of W and Z-boson production cross-sections in pp collisions at √s = 13 TeV with the ATLAS detector, Phys. Lett. B 759 (2016) 601.
  • G. Aad et al. [ATLAS Collaboration], Measurements of the production cross-section of a Z boson in association with jets in pp collisions at √s =13 TeV with the ATLAS detector, Eur. Phys. J. C77 (2017) 361.
  • M. Aaboud et al. [ATLAS Collaboration], Cross-section measurements of the Higgs boson decaying into a pair of tau-leptons in proton-proton collisions at √s = 13 TeV with the ATLAS detector, Phys. Rev. D 99 (2019) 072001
  • M. Aaboud et al. [ATLAS Collaboration], Evidence for the production of three massive vector bosons with the ATLAS detector, Phys. Lett. B 798 (2019) 134913
  • M. Aaboud et al. [ATLAS Collaboration], Measurements of the production cross-section for a Z boson in association with b-jets in proton-proton collisions at √s = 13 TeV with the ATLAS detector, JHEP 07 (2020) 044
  • ATLAS collaboration, Measurements of the production cross-section of a Z boson in association with high transverse momentum jets in pp collisions at √s = 13 TeV with the ATLAS detector, ATLAS-CONF-2021-033
  • ATLAS collaboration, Search for heavy resonances decaying into a Z boson and a Higgs boson in final states with leptons and b-jets in 139 fb−1 of pp collisions at √s = 13 TeV with the ATLAS detector, ATLAS-CONF-2020-043

Reviews:

  • U. Blumenschein et al., Pushing the precision frontier at the LHC with V+jets', hep-ex/1802.02100 .
  • U. Blumenschein, Jet production in association with vector bosons or top quarks ,Int. J. Mod. Phys. A, 30, 1546007 (2015).

Complete list of publications with my involvement:

 

Supervision

This is not an exhaustive list and I would be happy to discuss other project possibilities.

 
                                             Project Title 

 

 

Search for a massive Higgs boson

Production of a Z boson in association with jets

 

Public Engagement

EPPOG master classes

In 2018, I have organised the EPPOG Master Classes in QMUL

St Pauls summer school

In 2019, I have givan a lecture about particle accelerators at the St Pauls summer school 

 

Performance

  • Conference organisation:

    Talks at international conferences:

    • Sfermions at LEP2, Higgs and Supersymmetry Conference, 2001 in Orsay on behalf of the LEP experiments.
    • Limits on the mass of the lightest supersymmetric particle at LEP, 16th Int. Conf. on Particles and Nuclei (PANIC) 2002 in Osaka on behalf of the LEP experiments. 
    • Search for Associate Chargino Neutralino Production in the Trilepton Final States, Meeting of the Division of Particles and Fields of the American Physical Society, (PDF) 2004 in Riverside, on behalf of the D0 Collaboration
    • Jets and Jets+MET Studies at the LHC, Rencontres de Moriond, QCD and High Energy Interactions 2008, on behalf of the ATLAS Collaboration
    • ATLAS WZ Physics, LHC days 2010 in Split, Croatia, on behalf of the ATLAS Collaboration
    • ATLAS W/Z+jets, LHC EW WG meeting, Nov 2011 in Geneva, on behalf of the ATLAS Collaboration
    • ATLAS SM and top Physics, 13th Marcel Grossmann Meeting, 2012 in Stockholm, on behalf of the ATLAS Collaboration.
    • V+jets measurements at ATLAS, CERN LPCC seminar, 2013, Geneva, Switzerland
    • Measurements of the production of vector bosons in association with heavy flavour quarks at the LHC, LHCP in New York, 2014, on behalf of the ATLAS Collaboration.
    • Top and electroweak measurements, plenary presentation at the 38th International Conference on High Energy Physics (ICHEP 2016) in Chicago, 2016.
    • QCD measurements at the LHC, LFC17, Old and New Strong Interactions from LHC to Future Colliders, Villazzano, Trento, Italy, 2017
    • Standard-Model measurements at the LHC, Joint APP and HEPP Annual Conference, Bristol, 2018    
    • Differential measurements of the Drell-Yan cross-sections, presentation at the XXVI International Workshop on Deep-Inelastic Scattering and Related Subjects, DIS, in Kobe, Japan, 2018.
    • Precision measurements at ATLAS and CMS, international DESY Theory Workshop, Hamburg, Germany, 2018