Doctoral student in Physics with specialization in experimental particle physics

The LDMX group at Lund University seeks a skilled and motivated doctoral student to participate in our efforts to get LDMX online and make the most of its data.

This doctoral student position will be part of the Lund LDMX group (LunDMX, https://www.particle-nuclear.lu.se/experimental-particle-and-nuclear-physics/ldmx ), embedded in the division for particle and nuclear physics (https://www.particle-nuclear.lu.se/) at the physics department. The division with about 60 employees comprises a lively mixture of active research in theoretical and experimental particle, and heavy ion physics, and experimental nuclear physics. The experimental particle physics activities include research at the well-established LHC experiments ATLAS and ALICE as well as efforts to realise new, creative experiments like HIBEAM/NNBAR at ESS and – the focus of this project – LDMX at SLAC (https://confluence.slac.stanford.edu/display/MME/Light+Dark+Matter+Experiment). LDMX will be a fixed-target experiment in an 8 GeV electron beam extracted from the upgraded LCLC-II accelerator. Its main objective is to conclusively test models of sub-GeV thermal-relic dark matter over several orders of magnitude in mass range. Within the division, we exploit synergies across these different projects, and our contributions include detector development, trigger and DAQ, physics and performance analysis as well as software development and computing.  The LunDMX group currently consists of a senior researcher, three faculty members, a postdoc, an engineer, and two Ph.D. students. 

Project description

The overarching theme of this project is to get ready for LDMX data (expected during 2029). The work will be conducted in close connection with the international LDMX collaboration, in which Lund University is currently the only non-US participant.

One exciting milestone for LDMX is a beam test at SLAC in the autumn of 2025, for the first time collecting data at the actual beam line for LDMX, which will be operated parasitically to the photon science conducted with LCLS-II. In addition, we plan to collect cosmics data with a prototype of the hadronic calorimeter. During the first 1-2 years, roughly, this project will be focused on the gathering and, in particular, on the analysis of these test measurements and on publishing the results.

Another priority in this project will be to study the capabilities of LDMX to handle pile-up (multiple electrons hitting the target at the same time) in more detail. This will mainly be based on simulation-studies of potential backgrounds, detector performance, and physics sensitivities. One concrete example is the use of different codes for simulating critical backgrounds, comparing their predictions and developing methods for how to measure these backgrounds in data. The project also aims to explore to which extent machine learning methods can help with these tasks, e.g. object reconstruction and signal vs background discrimination. This will become more of a focus later in the project.
Beyond the direct physics questions, the project will also engage with questions of climate sustainability in LDMX/HEP, for instance by identifying the main emission sources and investigating how to minimize the related emissions.

Work tasks and duties

The main duties of doctoral students are to devote themselves to their research studies, which include participating in research projects and third-cycle courses. The work duties can also include teaching and other departmental duties (no more than 20%).

As a doctoral student in the LunDMX group, you will contribute to the data analysis of the test measurements performed with different detector prototypes.

Beyond that, you will perform simulation-based studies of different aspects feeding into the physics potential of LDMX. This will require the use (and further development) of different simulation tools, mainly the GEANT4-based ldmx-sw framework (https://github.com/LDMX-Software/ldmx-sw ), written in C++, maintained on github and configured via python.

You will work with .root files and explore different event generators as well as machine learning tools and algorithms.

The nature of LDMX as an international project will require you to work collaboratively in an international research environment.

Your main place of work will be at the Physics Department in Lund, but trips to SLAC/our collaborators may also become necessary.

The position requires clear and thoughtful communication, both within the scientific community and with the public.

You will contribute to the development and maintenance of the common LDMX software.

You will be responsible for documentation and reporting of your research activities, maintaining detailed records of your work, preparing documentation for future users and following the LDMX requirements for contributing to documentation.

You are expected to participate in mentorship and training of students, fostering a collaborative and knowledge-sharing environment.

You will be given the opportunity to seek external research funding for travel or small projects.

Your tasks will also include taking care of administration related to the duties outlined above. 

Entry requirements

Admission requirements

A person meets the general admission requirements for third-cycle courses and study programmes if he or she:

• has been awarded a second-cycle qualification, or
• has satisfied the requirements for courses comprising at least 240 credits of which at least 60 credits were awarded in the second cycle, or
• has acquired substantially equivalent knowledge in some other way in Sweden or abroad.

A person meets the specific admission requirements for third-cycle studies in Physics if he or she has:

• independent project (e.g.degree project) of at least 30 credits in a relevant subject

Equivalent knowledge acquired through corresponding programmes will be assessed individually. In order to enable interdisciplinary initiatives and important specializations in certain areas, students with qualifications in subjects other than Physics may be considered for admission.

Finally, the student must be judged to have the potential to complete the programme.

Additional requirements:

• Very good oral and written proficiency in English.
• Collaborative skills in order to work in an international collaboration
• Prior experience at least at a basic level in programming in C++ and/or Python

Other assessment criteria

Below follows a list of qualifications that should be read as “and/or”, not “and” – if you fulfil any of the listed requirements, it is a plus, but we do not expect you to tick all the boxes simultaneously.

• Prior experience in experimental particle physics and data analysis
• Prior experience with machine learning tools
• Prior experience in developing algorithms such as particle identification, specific final state event selection, or object reconstruction
• Interest in student supervision (bachelor, master)
• Prior experience in environmental sustainability

Basis of assessment

Selection to postgraduate studies is based on the expected ability to perform well in the studies. The evaluation of the ability to perform well is based primarily on the results of studies at the basic and advanced levels, in particular:

1. Knowledge and skills relevant to the thesis project and the subject of the study.
2. An assessment of ability to work independently and to formulate and tackle research problems.
3. Written and oral communication skills
4. Other experience relevant to postgraduate studies, such as professional experience.

Consideration will also be given to good collaborative skills, drive and independence, and how the applicant, through his or her experience and skills, is deemed to have the abilities necessary for successfully completing the third cycle programme.

Terms of employment

Only those admitted to third cycle studies may be appointed to a doctoral studentship. Third cycle studies at LTH consist of full-time studies for 4 years. A doctoral studentship is a fixed-term employment of a maximum of 5 years (including 20% departmental duties). Doctoral studentships are regulated in the Higher Education Ordinance (1993:100), chapter 5, 1-7 §§.

Instructions on how to apply

Applications are to be submitted via the University’s online recruitment system. Applications shall be written in English.
Applications shall include:

• a 1-page cover letter stating the reasons why you are interested in the position and in what way the research project corresponds to your interests and educational background.
• a CV
• a degree certificate or equivalent (if the degree is not completed yet, please provide or short note from your programme supporting your projected graduation date, or something equivalent)
• a copy of your thesis or equivalent (alternatively a summary in case the thesis is not yet completed)
• contact information for at least two references
• other documents you wish to be considered (e.g. grade transcripts)

As part of the application process, you will be asked to answer a few questions in the recruitment system.
Applicants that are called for an interview might be asked to provide a work sample or to complete a knowledge test.
If need be, there will be more than one round of interviews.

Most welcome to apply!