Congratulations Ben! Very good news :)

Decay scheme of 214Bi to 214Po and subsequently to 210Pb. The diagram shows β-decays from 214Bi (left) either directly to the ground state (g.s.) or via excited states of 214Po (center). Approximately 80 excited nuclear states are accessible during the decay (symbolically represented). All these excited states deexcite via γ-decay emissions (red arrows), always including at least one transition greater than 609 keV. The final step is the α decay of 214Po (black arrow) directly to the stable ground state of 210Pb (right).

Comparison of the experimental data from XENONnT with the CVC theoretical spectrum (filled histogram).

New paper in PRC: with data from XENONnT, we measured the 214-Bi β-decay spectrum to the ground state of 214-Po, a first-forbidden non unique decay. The prediction based on the conserved vector current (CVC) hypothesis yields the best description of the data: journals.aps.org/prc/abstract...

A comet with a bluish head and long, thin tail against background stars.

Bartlomiej Grzywacz in Poland captured #Comet R3 PanSTARRS low above the horizon on Thursday. Thank you, Bartlomiej! ☄️🔭📸
buff.ly/ROtbCaj

Have you seen #Comet R3 PanSTARRS yet? See more pics of the comet and a finder chart:
buff.ly/0iBbMTv

If you're in Zurich, join us for today's physics colloquium, by Marie-Cécile Piro, on detecting the invisible! colloquium.phys.ethz.ch/programme/cu...

Black holes aren’t black A half century after the discovery of Hawking radiation, we are still dealing with the quantum puzzle it exposed.

The black hole information paradox has puzzled researchers for a half century. Cosmologist and science communicator @clairelamman.bsky.social illustrates the paradox and its implications in a new scrollable comic. #astronomy #comic #blackholes

IceCube expands neutrino search to spot fainter signals A major upgrade to the 15-year-old detector will aid in the study of neutrino oscillations.

The finer details of neutrino oscillations were outside the sensitivity of @icecubeneutrino.bsky.social—until now. The recently upgraded experiment has a new mission to determine neutrino mass ordering, one of the highest priority questions in particle physics. #physics #icecube

Preparations for the next run (with LArS, for Legend)

XENONnT 95% CL upper bound on the CSL model parameters, compared to exclusion limits from other non-interferometric experiments and theoretical propositions. Shaded areas mark the excluded regions of the allowed parameter space.

We searched for x-rays in XENONnT's low-energy data, as predicted from dynamical quantum collapse models, and improved upon previous constraints by up to two orders of magnitude: journals.aps.org/prl/abstract...

and sometimes in dark matter detectors ;)

Ig Nobels to move awards to Europe due to concern over US travel visas Scientific awards – which honor research that makes people laugh and then think – to move away from ‘unsafe’ US

🧪 🇨🇭 #IgNobel awards come to Switzerland as US unsafe for scientists
#HoppSchwiiz
www.theguardian.com/science/2026...

Cherry tree in Ueno Park

Hongo Campus of the University of Tokyo

My way to work this week crossed one of my favorite parks in Tokyo ;)

"The density required was far in excess of uranium.”

“...one of my Soviet colleagues suggested that, perhaps, the effect was due to regeneration of short-lived K mesons in a fly unfortunately trapped in the helium bag. We did a quick “back of the envelope” estimate of the density of the fly necessary to produce the effect."

“Upon learning of the discovery in 1964, the natural reaction of our colleagues was to ask what was wrong with the experiment. Or, if they were convinced of the correctness of the measurements, they asked how could the effect be explained while still retaining CP symmetry.” Jim Cronin, 1980

"Voyages of discovery can be made in new uncharted waters but also in the familiar bays close to port provided one has observing apparatus that can see familiar objects with detail greater than that previously possible.”

Teaching is a good excuse to read old Nobel lectures: “Most often experiments in physics are long and difficult. It takes some special tweaking of interest to make the commitment to a new area of research. The original motivation is, in the end, apt to appear naive.” Val L. Fitch, 1980

If you're in the Zurich area, join us for a special Schrödinger Colloquium on Monday. “From Atoms to Cosmos” will celebrate 100 y of Schrödinger equation, bridging chemistry, physics and cosmology. A surprise quantum dance event will follow in the Lichthof, with Priscilla Roeck & Killian Haselbeck

So far so good

Yes I should prepare my lectures for next week (semester start), I should read a PhD thesis, among others… but this was my main project for today - happy valentines ;)

Nice article, by Adam Begley, about Julian Barnes and his new book, Departure(s), in the @theatlantic.com “We must believe in love, just as we must believe in free will and objective truth.”

time ;)

Xenoscope, a tall xenon TPC, and its support structure

A new run with Xenoscope, a 2.6 m tall, two-phase xenon tome projection chamber, will start soon. Now the TPC is being reassembled and it looks almost like new ;-)

Muons are wonderful particles. Happy to be part of the new National Centre of Competence in Research "Muoniverse" www.muoniverse.ch, hosted by PSI & UZH. Muoniverse is one of the six funded new centres (www.wbf.admin.ch/en/newnsb/JE...), connecting science, engineering and arts. More details soon!

The energy spectrum of the first LEGEND-200 dataset, corresponding to 61.0 kg yr of germanium exposure, above the  39-Ar 𝑄_𝛽 =565  keV. The white histogram shows events passing quality and muon anticoincidence cuts and with energy deposited in one single HPGe detector. The main radioactive background contributors are indicated in green. The gray and red histograms show the subsets of events passing the PSD cut and additionally the LAr anticoincidence cut, respectively. The inset shows a close-up around the region of interest for 0⁢𝜈⁢𝛽⁢𝛽 decay with finer binning. The expected contribution from the 2⁢𝜈⁢𝛽⁢𝛽 decay of 76-Ge corresponds to the solid blue line. The events used to set a constraint on the 0⁢𝜈⁢𝛽⁢𝛽 decay rate are contained by the analysis window, marked in green. Only two significant 𝛾 peaks (shaded areas) are expected within this window, and the corresponding 10 keV wide energy regions are excluded from the statistical analysis.

The first LEGEND-200 results are now published in @physrevlett.bsky.social journals.aps.org/prl/abstract...
No evidence for neutrinoless double beta decay,
with a lower limit on the 76-Ge half-life of 1.9 x 10^26 y. This corresponds to an upper limit on the Majorana ν mass of m_ββ < 75 - 200 meV

Using the Hubble Space Telescope 🔭, a team of astronomers have discovered a starless, gas-laden dark matter cloud believed to be a relic from the dawn of galaxy formation - the first verified discovery of its kind anywhere in the Universe ☁️. Check it out: https://ow.ly/e0WV50XT9Og #astronomy

You need to align with Polaris and then you can use the guiding scope for corrections

I meant photons (but also photos ;)

Plenty of photos here last night, but mostly from the moon ;)

It moves! We can watch as the Kepler supernova remnant changes over a quarter of century in X-rays from Chandra. #aas247
chandra.si.edu/photo/2026/k...

Sydney Opera House

This spectacular image of the planetary alignment of Saturn, Mars, Venus, and Jupiter above the Sydney Opera House was taken in the early morning around April 21, 2022, and featured as NASA's Astronomy Picture of the Day on April 26, 2022