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Freya Blekman @freyablekman.bsky.social · 12h

Definitely time to go home as i cannot spell breakthrough

Freya Blekman @freyablekman.bsky.social · 12h

I love my colleagues, after a super long exhausting day (where I got to push the limits of the CERN mail servers, if you are on CMS you may received one of those mails) I get to put my #breaktroughprize into a frame that a sweet colleague gave me.

Now time for downtime!

Freya with her now framed breakthrough prize certificate

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Freya Blekman @freyablekman.bsky.social · 12h

This #CMSPaper explores the excitation of three particles with a B quark and other quark, examining how they store extra energy beyond the ground state. It marks the first simultaneous measurement of these particles. This improves knowledge of particles that contain quarks arxiv.org/abs/2508.05820

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Freya Blekman @freyablekman.bsky.social · 18h

Are there undiscovered particles that decay to a Higgs boson and something else? This #CMSPaper describes how we scanned the invariant mass spectrum, but did not find any signs (in very very few events, and this should be rare. We will do this again when we have more data) arxiv.org/abs/2508.11494

Invariant mass distribution looking for a Higgs boson (in the diphoton decay)

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Freya Blekman @freyablekman.bsky.social · 1d

The LHC produces a large number of Z bosons. So it is worthwhile checking if some of them behave inconsistently with the standard model. This #CMSPaper measured that the chance that Z bosons decay to two different kinds of leptons is smaller than one in 10 million arxiv.org/abs/2508.07512

searchign the e-mu invariant mass for a Z boson peak. No sign.

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Freya Blekman @freyablekman.bsky.social · 1d

Are there undiscovered particles (that are very light for LHC standard) produced in Higgs boson decays? This #CMSPaper describes how we look for them, but did not see any arxiv.org/abs/2508.06947

invariant mass distribution that is nicely falling. The data agrees with the blue prediction (which is the standard model). The scenarios considered would modify these signatures dramatically (other coloured lines)

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Freya Blekman @freyablekman.bsky.social · 2d

If you need a reference model of what an extension of the standard model with many new particles would look like, Supersymmetry is a good benchmark. This #CMSPaper shows a general search in many standard signatures, looking for deviations spread over different signatures arxiv.org/abs/2508.13900

competitive limits on supersymmetric lepton partners (aka sleptons)

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Freya Blekman @freyablekman.bsky.social · 2d

Are there invisible (and long-lived) undiscovered particles produced in the decays of B mesons? Those would be super rare, so we use a huge dataset of B mesons with dedicated data taking techniques. We didn't see any new particles though, this #CMSPaper is a #nullresult arxiv.org/abs/2508.06363

limit plot, measuring that in the most sensitive scenarios that if such an undiscovered particle exists, it shows up in fewer than 1/10000 B mesons

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Freya Blekman @freyablekman.bsky.social · 2d

Yes. And now with crispy pistachios

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Freya Blekman @freyablekman.bsky.social · 2d

Unpopular opinion: #dubaichocolate is made with low quality chocolate and is horrible.

Open to recommendations without shitty palm fat or sub 50% cocoa chocolate and with sugar levels suitable for adults instead of toddlers

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Freya Blekman @freyablekman.bsky.social · 3d

Missing momentum is effectively the only way that the main detectors at the LHC (like CMS) can measure the indirect signs of neutrinos (or undiscovered particles). This #CMSPaper present how we use #machinelearning to make our missing momentum measurement much, much better: arxiv.org/abs/2509.12012

Plot showing how the Deepmet algorithm improves the missing energy reconstruction of the very well-known W boson particle. Compared to the previous best algorithms (it's really very good!)

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Freya Blekman @freyablekman.bsky.social · 3d

Earlier this week, Dominic, a postdoc in our team, also had a two hour delay in switzerland (on the Hamburg->Geneva route)

a cartoon character says " it 's all over people " in front of a house

ALT: a cartoon character says " it 's all over people " in front of a house

media.tenor.com

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Freya Blekman @freyablekman.bsky.social · 4d

don't worry, I still have plenty of complaints:

- it's raining in Hamburg
- I spilt coffee on myself halfway so had to travel with dirty (but still awesome) deftones t-shirt

do note that there were a lot of children near me on the train and they all behaved. So that's a plus.

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Freya Blekman @freyablekman.bsky.social · 4d

Especially for the haters I would like to confirm that my train trip arrived 6 minutes EARLY from CERN, Geneva to DESY, Hamburg (ok to my home in Hamburg), that’s 1250 km, 2 changes.

Map of Europe with train route from Geneva to Hamburg. It’s far.

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Freya Blekman @freyablekman.bsky.social · 4d

You may have noticed that I stopped numbering the #CMSPapers I posted about. This is mostly because the numbering is kind of ambiguous. But we have published over 1400 papers (of which 1370+ on LHC data) since 2009 already!

check them all out (searchable) here: cms-results-search.web.cern.ch

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Freya Blekman @freyablekman.bsky.social · 4d

This #CMSPaper measures D mesons (particles containing charm and other quarks) produced in collisions when the LHC works as a photon-heavy ion collider. These results help as input to nuclear physics in general, and used in predictions in astrophysics, for example arxiv.org/abs/2509.08626

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Freya Blekman @freyablekman.bsky.social · 5d

We have enough Higgs bosons now to measure kinematics and check for additional quarks and gluons formed. These numbers could vary due to slight changes in the standard model from undiscovered particles. This #CMSPaper compares these distributions to the standard model arxiv.org/abs/2509.07958

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Freya Blekman @freyablekman.bsky.social · 5d

We don't see the decay of the Higgs boson to charm quarks (yet!), but it is also possible to measure the interaction of the Higgs boson with charm by studying those particles being produced together. This #CMSPaper studies that Higgs+charm signature (we don't see it yet): arxiv.org/abs/2508.14988

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Freya Blekman @freyablekman.bsky.social · 6d

This #CMSpaper looks again at a non-significant (but intriguing!) excess in signatures consistent with two unstable, unknown particles from a heavier source. This paper further compares to theory predictions explaining these four-jet events
arxiv.org/abs/2507.17884

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Freya Blekman @freyablekman.bsky.social · 6d

This #CMSPaper explores the excitation of three particles with a B quark and other quark, examining how they store extra energy beyond the ground state. It marks the first simultaneous measurement of these particles. This improves knowledge of particles that contain quarks arxiv.org/abs/2508.05820

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Freya Blekman @freyablekman.bsky.social · 7d

Are there undiscovered particles that decay to a Higgs boson and something else? This #CMSPaper describes how we scanned the invariant mass spectrum, but did not find any signs (in very very few events, and this should be rare. We will do this again when we have more data) arxiv.org/abs/2508.11494

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Freya Blekman @freyablekman.bsky.social · 7d

Yesterday I got to geek out when I visited some of the labs where we are building the new detectors for the LHC upgrade. Can you guess what this little sub-sub-subdetector is for?

Hint: it’s not made of glass but of scintillation crystals…

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Freya Blekman @freyablekman.bsky.social · 8d

The LHC produces a large number of Z bosons. So it is worthwhile checking if some of them behave inconsistently with the standard model. This #CMSPaper measured that the chance that Z bosons decay to two different kinds of leptons is smaller than one in 10 million arxiv.org/abs/2508.07512

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Freya Blekman @freyablekman.bsky.social · 8d

Are there undiscovered particles (that are very light for LHC standard) produced in Higgs boson decays? This #CMSPaper describes how we look for them, but did not see any arxiv.org/abs/2508.06947

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Freya Blekman @freyablekman.bsky.social · 9d

If you need a reference model of what an extension of the standard model with many new particles would look like, Supersymmetry is a good benchmark. This #CMSPaper shows a general search in many standard signatures, looking for deviations spread over different signatures arxiv.org/abs/2508.13900

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