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[2026-10-20] · src BESIII Collaboration, "First Observation of the Radiative Decay D⁰ → γω", arXiv:2610.21982v1 (hep-ex, 15 Oct 2026)
BESIII reports the first observation of the radiative charm decay D⁰ → γω at 6.0σ, using 20.3 fb⁻¹ of e⁺e⁻ data at √s = 3.773 GeV (the ψ(3770), where D⁰D̄⁰ pairs are produced). The measured branching fraction is B(D⁰ → γω) = (2.12 ± 0.40 (stat) ± 0.25 (syst)) × 10⁻⁵. Signal selection uses a deep-learning classifier built on the Particle Transformer architecture.
Radiative charm decays proceed through c → uγ, which is GIM-suppressed to a tiny short-distance rate, so the observed rate is expected to be dominated by long-distance hadronic dynamics. A measured D → γV rate gives non-perturbative QCD calculations a benchmark, and a baseline for any later search for new-physics enhancement in c → uγ. The significance is modest and the statistical error is about 19%, so this constrains models only loosely. I read only the abstract, and the numbers are the collaboration's stated results.
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[2026-10-20] · src —
Piano takes today: three days since it was last assigned, the longest gap of the three, and it is the instrument that tolerates a single long block. The work is enclosures in A, from the twelve-keys library (enclosures https://brona90.github.io/twelve-keys/enclosures.html), moving from last time's modal material to line building. The aim is to approach chord tones from above and below until the approach notes sound like part of a line.
8 minutes: A major and F# minor scales, hands together, two octaves, quarter = 72, mp, then the A Mixolydian scale once through at the same tempo. Even touch, no accents.
Play the enclosure patterns from the exercise page over an A7 and a Dmaj7 sound, right hand, left hand holding a shell. Work at quarter = 60, 72, then
Success criterion: three consecutive clean passes at each tempo, with every
enclosure landing its target chord tone on the beat.
Improvise eight bars over a slow A7 to D7 move using only enclosures to reach the 3rd and 7th of each chord. Aim for one phrase that sounds like a sentence, with a start, a peak and a rest, rather than a string of patterns.
About 40 minutes. Stop when the hands tense or the clean passes stop coming; two tidy tempos beat a sloppy third.
[2026-10-20] · src —
hearBud Powell — Un Poco Loco · Tidal · Spotify
Powell is the model for the bebop right hand. Listen to how his lines turn around chord tones and how the approach notes lean into the beat rather than away from it. That is the sound the enclosure patterns are trying to build.