Freya Blekman

Freya Blekman

@freyablekman.bsky.social

Particle physicist at @CMSExperiment at @CERN - Lead Scientist DESY & Professor of Physics University of Hamburg - World citizen βž‘πŸ‡³πŸ‡±πŸ‡ΊπŸ‡Έ πŸ‡¬πŸ‡§πŸ‡¨πŸ‡­πŸ‡§πŸ‡ͺπŸ‡©πŸ‡ͺ Posts: #physics #SciComm + academia/tech stuff + my opinions + summaries of #CMSpapers

3.6K followers639 following2.2K posts

Freya Blekman
@freyablekman.bsky.social

Academia, particularly above a certain career stage, is also about finding new funding opportunities. Today I’m all dolled up to do exactly that, and on my way to Heidelberg on the early train. Fingers crossed/pushing thumbs together

Freya Blekman
@freyablekman.bsky.social

Another successful PhD combining ambitious machine learning and particle physics! Congratulations to Shahzad Sanjrani, who defended his PhD on β€œPerformance of an attention-based neural network on the search for top-Philip resonances in the all-hadronic four-top final state at CMS”.

Freya Blekman
@freyablekman.bsky.social

Another successful PhD combining ambitious machine learning and particle physics! Congratulations to Shahzad Sanjrani, who defended his PhD on β€œPerformance of an attention-based neural network on the search for top-Philip resonances in the all-hadronic four-top final state at CMS”.

Freya Blekman
@freyablekman.bsky.social

This work is part of a long collaboration I have had with the University of Bristol, so Shahzad had the joy of two PhD advisors, one from DESY (me) and one from Bristol (Joel Goldstein)

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Freya Blekman
@freyablekman.bsky.social

These detectors use ice to detect some of the most difficult particles to see, neutrinos, and use those neutrinos for particle physics (study the neutrinos) and astronomy (use the neutrinos to study stars/galaxies/the universe).

Freya Blekman
@freyablekman.bsky.social

Fresh off the press: next year there will be another CERN open day: 24, 25 and 26 September 2027 ! (pic: a group I took to visit the CMS detector at one of the collision points of the large hadron collider. For CMS visits, guides have a white helmet, visitors in orange, or sometimes blue)

Freya Blekman
@freyablekman.bsky.social

This week I'm in sunny Graz in Austria, speaking about Higgs bosons and why we need a future collider to measure them properly, presenting a so-called mini-colloquium . It's at the 75th Annual Meeting of the Austrian Physical Society, good times will be had. I've never been to #Graz, any tips?

Freya Blekman
@freyablekman.bsky.social

Every layer of a Dolly Parton outfit had a job: structure, sparkle, warmth, all of it in service of the show. Particle detectors are built the same way, layer after layer, each tuned for a different job, working together to catch what matters. Thank you #DollyParton for the sparkle and the song

Freya Blekman
@freyablekman.bsky.social

Every layer of a Dolly Parton outfit had a job: structure, sparkle, warmth, all of it in service of the show. Particle detectors are built the same way, layer after layer, each tuned for a different job, working together to catch what matters. Thank you #DollyParton for the sparkle and the song

Freya Blekman
@freyablekman.bsky.social

Every layer of a Dolly Parton outfit had a job: structure, sparkle, warmth, all of it in service of the show. Particle detectors are built the same way, layer after layer, each tuned for a different job, working together to catch what matters. Thank you #DollyParton for the sparkle and the song

Freya Blekman
@freyablekman.bsky.social

I am a scientist working at CERN. If you have questions, I can answer them. Honestly. But beware, I will also call πŸ„ πŸ’© (and why)

Michael Hobbes@michaelhobbes.bsky.social

TikTok is obsessed with the idea that the CERN shutdown caused a global disruption in women's menstruation patterns.

Freya Blekman
@freyablekman.bsky.social

Every layer of a Dolly Parton outfit had a job: structure, sparkle, warmth, all of it in service of the show. Particle detectors are built the same way, layer after layer, each tuned for a different job, working together to catch what matters. Thank you #DollyParton for the sparkle and the song

Freya Blekman
@freyablekman.bsky.social

It also offers a way to distinguish an ALP near the ttΜ„ threshold from toponium, since an ALP shows up in both ttΜ„ and four-top final states while toponium does not. And HEPData by new PhD student Saurav Bania, who did a stellar job joining the team mid-review.

Freya Blekman
@freyablekman.bsky.social

CMS internal review took about three quarters of a year in total which is fast. So check out our paper arxiv.org/abs/2608.10148 and we are also preparing a physica briefing. But it is vacation so that will come

arxiv.orgSearch for a resonance in events with four top quarks decaying into two leptons and jets in proton-proton collisionsA search for a heavy resonance in events containing four top quarks is presented and interpreted in models featuring a new vector, scalar, or pseudoscalar boson that interacts exclusively with top qua...
Freya Blekman
@freyablekman.bsky.social

The search is sensitive to vector, scalar and pseudoscalar mediators. The most forward-looking piece: the first reinterpretation of a four-top search in terms of axion-like particles coupling to top quarks (we didn’t see any but those would also not likely be visible now in many likely scenarios).

Freya Blekman
@freyablekman.bsky.social

This result probes a mass range that neither ttΜ„ resonance searches nor missing-momentum searches cover, and could only work because of expertise by Dominic Stafford and theory colleagues from the Cluster of Excellence Quantum Universe.

Freya Blekman
@freyablekman.bsky.social

A machine-learning top tagger, designed by Gabriele Milella. An algorithm identifies which of those jets genuinely contain a hadronically decaying top, much better than the previous selection-based approach at the same misidentification rate. Exactly the gain the low-mass region needed.

Freya Blekman
@freyablekman.bsky.social

A new final state. This is the first dedicated search of its kind requiring two leptons. Cleaner signature, and complementary to the single-lepton searches that came before. Run 3 data. Besides Run 2 data of course, and important when looking for something this rare. the first for this signature.

Freya Blekman
@freyablekman.bsky.social

The obstacle has always been experimental, and the fact that this signature is super rare, so we can only probe it now with the huge datasets we have available. What is new, and took loads of #datascience #algorithmic work

Freya Blekman
@freyablekman.bsky.social

Variable-radius jets. Using a p_T-dependent distance parameter, we reconstruct the mediator mass from a pair of jets from 500 GeV to 4 TeV. This opens up the region below 1 TeV, and uses a great DESY / University of Hamburg algorithm designed by my colleague Roman Kogler (et al).

Freya Blekman
@freyablekman.bsky.social

New CMS paper out: arxiv.org/abs/2608.10148 #particlephysics #paperday My team at DESY was deeply involved in this analysis. It is also the first of my CMS papers that is truly a DESY product since my move to Hamburg a few years ago through the Helmholtz Association recruitment initiative.

arxiv.orgSearch for a resonance in events with four top quarks decaying into two leptons and jets in proton-proton collisionsA search for a heavy resonance in events containing four top quarks is presented and interpreted in models featuring a new vector, scalar, or pseudoscalar boson that interacts exclusively with top qua...
Freya Blekman
@freyablekman.bsky.social

We look for undiscovered hypothetical particles that couple only to top quarks, because this is one of the few places new physics can still very comfortably hide at the LHC. Four-top-quark events are among the most direct ways to probe that.

Freya Blekman
@freyablekman.bsky.social

Ambitious #science and definitely particle physics are almost always a #team effort. This is also true for conferences. Here you see Pedro (Portugal), Azwinndini (South Africa), Kate (UK), Sandra (Brazil), and friends, together we presently are organising a track at the #ichep2026 conference

Freya Blekman
@freyablekman.bsky.social

A connection of mine is editing a book on Science and Sustainability. They need more data on views by early career scientists so made a survey. In case you are an ecr and this interests you, please complete the survey at forms.gle/K5AJSbuCsKdR... #sustainability #science #earlycareerscientists

forms.gleSustainability researchSurvey of Attitudes and Commitments. The purpose of this survey is to gauge public perception of sustainable development concepts.
Freya Blekman
@freyablekman.bsky.social

This week I’m at a conference. Physics conferences have of course talks about physics, but about much more! For example this morning, I gave a talk about how we run our group Instagram account (and why we do it that way) #ichep2026 particle physics is #openscience so talk is here: indi.to/vjPHb

Freya Blekman
@freyablekman.bsky.social

This time in random gear I found on campus: the monochromator You’ve probably seen a prism split light into a rainbow. X-rays can be split the same way with a crystal monochromator instead of glass. The antique monochromator in this video is a real piece of that history.

Freya Blekman
@freyablekman.bsky.social

oops something went wrong there. I was referring to Kuan-Yu Lin's work on the CMS HGCAL, see also www.instagram.com/p/Daw9QCoIsN...

instagram.comParticle physics by CMS experiment at DESY on Instagram: "Meet Dr Kuan-Yu Lin πŸ”¬, a postdoc working on CMS at DESY who is attending the NDIP: New Developments in Photodetection conference. Kuan-Yu is p...46 likes, 3 comments - cmsatdesy on July 14, 2026: "Meet Dr Kuan-Yu Lin πŸ”¬, a postdoc working on CMS at DESY who is attending the NDIP: New Developments in Photodetection conference. Kuan-Yu is present...
Freya Blekman
@freyablekman.bsky.social

Very nice scicomm of one of the recent papers in my group. We checked how the interplay between different collisions energies at future colliders (and which energy/amount of data is best) can help to find, or constrain, axion-like particles.

instagram.comParticle physics by CMS experiment at DESY (@cmsatdesy) β€’ Instagram photos and videos67 likes, 3 comments - cmsatdesy on June 23, 2026: "What if a new particle showed up as three photons? Axion-like particles, or ALPs, are hypothetical particles that appear in many extensions of the Standard...
Freya Blekman
@freyablekman.bsky.social

And quite a lot of nice UHH results there!

CMS Experiment at CERN@cmsexperiment.bsky.social

πŸ‘Well done to all the CMS students and early career researchers who prepared and presented their posters at the June CMS WeekπŸ‘ Poster presentations and discussions are key in sharing insights into all areas of an experiment involving over 6000 people!