School of Physics and Astronomy

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, 1-2 pm, Wednesdays, 2-3pm

Teaching

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, modul co-organizer)
  • SPA5201 Physics Laboratory (Semester B, modul co-organizer)
  • SPA7029U/P Collider Physics (4th year, Semester B, deputy module organizer)

2019/20:

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

I have been organising the NExT School 25-28 June 2018 and gave a lecture series at the Hadron collider school 2019 in Goettingen.

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 Projects:

 

BSc and MSc Projects:

  • Regularized unfolding in hadron collider measurements
  • Modelling of background processes to collinear Z emission
  • Using Machine Learning  to improve the search for new heavy Higgs bosons
  • Review of 2-Higgs-Doublet models and experimental tests at colliders

 

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 mimick 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 wich go beyond that and pedict two Higgs doublets (2HDM)  with five massive Higgs bosons, could help understand why we have more matter than antimtter in our universe. In such a model, a heany 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

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 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 sqrt{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 sqrt{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 sqrt{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 colllisions at sqrt{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 sqrt{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 sqrt(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

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).

 

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 Trilepton Final States, Meeting of the Division of Particles and Fields of the American Physical Society, (DPF) 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, Croacia, 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