Andreas Papaefstathiou

Assistant Professor of Physics

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Andreas Papaefstathiou The aim of my research is to understand the basic building blocks of matter and energy and their interactions. This involves the study of the tiniest particles that we know of - quarks, leptons, gauge bosons and the Higgs boson.

Collider Experiments

One of the best ways to investigate Nature at the sub-microscopic level is through experiments that rapidly smash particles together at very high energies, and record the outcomes. The biggest such experiment is the CERN Large Hadron Collider in Geneva, Switzerland, colliding protons together at 99.9999991 percent the speed of light.

I specialize in the phenomenology of particle physics. In particular, I write simulation tools and perform calculations that are crucial for the success of modern particle physics experiments. These tools allow us not only to predict what will be seen at experiments, but also to design future experiments and interpret their results.

Undergraduate Research Opportunities

Are you an undergraduate student keen on conducting cutting-edge research within the realm of particle physics (and beyond!)? Contact me via e-mail if you are interested! A non-exhaustive list of possible projects can be found on my "Student Projects" page.

First-Year Scholars (Fall 2024) see here for intro presentation & the Symposium presentation (4/17/25)!

Computational Physics I (Spring 2024/25): Book draft available here.

Education 🎓

2011 Ph.D. in Theoretical Physics, University of Cambridge, United Kingdom.
2007 MPhys in Physics, University of Manchester, United Kingdom.

Previous Employment 💼

2019-2021 Post-Doctoral Researcher, University of Edinburgh, United Kingdom.
2016-2019 Post-Doctoral Researcher, University of Amsterdam & Nikhef, The Netherlands.
2014-2016 Post-Doctoral Fellow (Marie Skłodowska-Curie Fellowship), European Organisation for Nuclear Research (CERN), Switzerland.
2011-2014 Post-Doctoral Researcher, University of Zürich, Switzerland.

Professional Positions👨🏽‍🔬

CERN Visiting Scientist (Theory Department).
MCnet Board Member.
LHC Higgs Cross Section Working Group Theory Convener (WG4).
SciPost Journal Editorial College Member.

News 🗞️

[5/22/25] Collider CrossTalk at CERN, on Triple Higgs boson production at the LHC.
[5/14/25] Plenary talk on Resonant Triple Higgs boson production at the HiggsPairs 2025 workshop in Elba, Italy.
[4/17/25] Short presentation by my students (Tyler Poole & Caleb Helbling) at the KSU Research Symposium as part of the First Year Scholars program, see here.
[1/24/25] New pre-print out: https://arxiv.org/abs/2501.14866, examining double-resonant triple Higgs boson production at the LHC via a simplified approach.
[1/21/25] My DOE FAIR grant ($799,651) has been officially awarded. Click here for the public abstract.
[11/21/24] My project has been selected for funding by the Department of Energy, under the FAIR initiative: "Monte Carlo Simulations for Polarized and In-medium Parton Evolution in the Nuclear Realm", with Yang-Ting Chien as Co-PI at Georgia State University.
[11/8/24] The first experimental results on triple Higgs boson production have been released by the LHC ATLAS collaboration, see article here.
[10/25/24] Talk at "Extended Scalar Sectors From All Angles" workshop (CERN, Geneva, Switzerland).
[9/11/24] Talk at Institute of Nuclear and Particle Physics, NCSR Democritus (Athens, Greece).
[7/31/24] Talk at "Mini workshop on HHH and other extended scalar sector signatures" at Ruđer Bošković Institute, Zagreb, Croatia, available here.
[7/3/24] New pre-print summarizing results for triple Higgs boson production: HHH Whitepaper [https://arxiv.org/abs/2407.03015]
[6/5/24] New pre-print: 𝙿𝚢𝚛𝚎𝚜𝚒𝚊𝚜: How To Write a Toy Parton Shower [https://arxiv.org/abs/2406.03528]. The associated code repository can be found here.
[5/24 & 28 & 31/24] Seminars at Nikhef (The Netherlands), Durham IPPP (UK) and U. Manchester (UK), available here.
[5/1/24] Seminar at Wichita State University, Kansas, available here.
[4/30/24] The Computational Physics I Online Book is available here!
[4/22/24] New pre-print out: Triple Higgs boson production and electroweak phase transition in the two-real-singlet model [https://arxiv.org/abs/2404.12425].
[12/20/23] New pre-print out: Multi-Higgs Boson Production with Anomalous Interactions at Current and Future Proton Colliders [https://arxiv.org/abs/2312.13562].
[10/25/23] New pre-print out: Using machine-learning methods to discriminate between black hole and sphaleron processes at the Large Hadron Collider [https://arxiv.org/abs/2310.15227].
[10/19/23] I gave a talk at the SCM 2000 course at KSU.
[9/29/23] Colloquium at Georgia State University, find the slides here and a YouTube video here.
[9/12/23] I gave a brief talk at the follow-up HHH meeting.

Publications 📖

You can find an up-to-date list of my publications in the INSPIRE database.

See the Computer Code page for my publicly-available open-source particle physics programs and tutorials.

Research🔬

Check out my Research page for an overview of my research activities and themes.

[Languages: 🇬🇧 🇬🇷 🇨🇾]

Older News

[7/15/23] I gave a talk at the "HHH Workshop", Dubrovnik, Croatia.
[3/28/23] New pre-print: "HEJ 2.2: W boson pairs and Higgs boson plus jet production at high energies." [https://arxiv.org/abs/2303.15778].
[12/9/22] New pre-print out with Jonathan Zuk, Csaba Balazs and Graham White on "The Effective Potential in Fermi Gauges Beyond the Standard Model" [https://arxiv.org/abs/2212.04046].
[12/6/22] The new webpage for MonteCarloNet is online [https://www.montecarlonet.org]. MonteCarloNet is an umbrella community for all working in methods, codes, and applications of general-purpose MC event generators. Kennesaw State University is a participating institute.
[10/19/22] New pre-print by the HEJ Collaboration "High Energy Resummed Predictions for the Production of a Higgs Boson with at least One Jet", [https://arxiv.org/abs/2210.10671].
[7/22/22] I have been awarded an NSF grant, "Deciphering Electro-Weak Scale Physics at Particle Colliders", see the relevant NSF page for the abstract.
[6/2/22] For a semi-popularized review of some of my recent work, check out our article with Graham White on the electro-weak phase transition at current and future colliders, written for the CERN Experimental Physics Newsletter: https://ep-news.web.cern.ch/content/deciphering-electro-weak-phase-transition-current-and-future-colliders.
[6/2/22] Talk at the Higgs Pairs Workshop (Croatia) on Triple Higgs boson production with extended scalar sectors.
[5/28/22] A contribution to the US "Snowmass" high-energy physics study that examines "Signal strength and W-boson mass measurements as a probe of the electro-weak phase transition at colliders" with Tania Robens and Graham White: https://arxiv.org/abs/2205.14379.