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[2026-09-24] · src BESIII Collaboration; arXiv:2609.25158 (2026-09-21)
Using 2712.4 +/- 14.3 million psi(3686) events, BESIII performs a model-independent partial wave analysis of the Lambda-antiLambda system produced in psi(3686) radiative decays and finds a resonance near 2.6 GeV/c2 in the 1S0 partial wave, designated eta(2600), with mass 2625 +/- 26 (stat) +/- 6 (syst) MeV/c2 and width 140 +/- 58 (stat) /- 46 (syst) MeV, at a statistical significance of 7.0 sigma. Its mass and width, and its production rate relative to eta_c, are consistent within uncertainty with the previously reported X(2600) seen only in J/psi -> gamma pi pi- eta', supporting the interpretation that eta(2600) and X(2600) are the same state - now confirmed in a second, independent production channel. Separately, and dominating the spectrum near threshold, the analysis also finds a broad structure, eta(Lambda-antiLambda), in the 1S0 and 3P0 partial waves (J^PC = 0^-+ and 0^++), with a model-dependent mass of 2169 +/- 150 MeV/c2 (Breit-Wigner fit) or 1899 +/- 66 MeV/c2 (a threshold-cusp-like lineshape) and width 480 +/- 97 MeV in the Breit-Wigner fit.
At 2.6 GeV/c2, eta(2600) is the heaviest light (non-charm, non-bottom) meson observed, and confirming X(2600) in a second channel removes the main objection to treating it as a real state rather than a channel-specific artifact - which matters because its mass and quantum numbers sit in the range where several groups have proposed a 0^-+ or 2^-+ glueball, a pseudoscalar hybrid, or a conventional but very highly excited eta/eta' radial excitation. This paper does not adjudicate between those interpretations; what it establishes is that the state is real and reproducible, which is the precondition any of those interpretations needs before it can be tested further. The near-threshold enhancement is a second, separate puzzle in the same dataset - baryon-antibaryon threshold structures like this one are notoriously hard to assign to a genuine resonance versus a kinematic cusp, and the two lineshape models here disagree with each other by over 250 MeV/c2 on the mass, which is itself the honest state of that question.
[2026-09-24] · src LHCb Collaboration; arXiv:2609.25370 (2026-09-21)
The heavy quark expansion (HQE) predicts that all weakly-decaying single-beauty baryons should have equal lifetimes at leading order, with the small differences between them - between Lambda_b0, Xi_b0, Xi_b- and Omega_b- - probing the size of the corrections beyond that order. The Omega_b- has been the weak link: its lifetime was known only to about 10% (world average 1.64 +/- 0.16 ps), far worse than the sub-1%-precision ratios now measured for the other baryons. Using 6 fb-1 of LHCb Run 2 data in two decay-mode sets (Omega_b- -> Omega_c0 pi- / Xi_b- -> Xi_c0 pi-, and both baryons -> J/psi + charged hyperon), combined with the earlier Run 1 measurement, LHCb now reports r_tau = tau(Omega_b-)/tau(Xi_b-) = 1.109 +/- 0.055 (stat) +/- 0.010 (syst), giving tau(Omega_b-) = 1.751 +/- 0.089 +/- 0.022 ps - roughly a factor of two improvement in precision on the Omega_b- lifetime itself. The result agrees with the HQE prediction r_tau^HQE = 1.054 +/- 0.046 within one standard deviation.
The Omega_b- is the one ground-state beauty baryon with a spin-1 diquark, so it alone probes the HQE's chromomagnetic operator term that vanishes for the others - this measurement is as much a test of a specific piece of the theory as it is a number. Doubling the precision on a baryon whose lifetime had been the least well known of the four, and finding agreement with the HQE prediction rather than a deviation, closes off (for now) the possibility that the Omega_b- was where higher-order HQE corrections would first show themselves. That is a calibrated non-result: it is exactly the sort of check that has to keep passing for lifetime-based extractions of CKM parameters elsewhere in the beauty sector to be trusted, and it passed.
[2026-09-24] · src Hammerstein, Chornock, Somalwar, et al.; arXiv:2609.28460 (2026-09-24)
Little is known about outflows from tidally disrupted stars before the optical light curve peaks, when stream-stream collisions and disk formation are thought to happen. This paper reports the first UV spectrum of any TDE taken before that peak: an HST/STIS spectrum of the nearby (z=0.0137) TDE2025aarm obtained about 20 days before optical maximum, with quasi-simultaneous IR-through-X-ray coverage. The spectrum shows broad near- and far-UV absorption lines blueshifted by ~10,000 km/s - direct evidence of a fast outflow already underway at this early phase - including two UV absorption features not previously identified in a TDE. The FUV-through-IR continuum deviates sharply from a single-temperature blackbody (f_lambda ~ lambda-3.08), which the authors interpret as reprocessing by the outflow itself; correcting for it implies the bolometric luminosity in this TDE is about 9 times higher than a standard blackbody fit to NUV-optical photometry alone would give.
Most TDE luminosities and energetics in the literature are derived from exactly the single-temperature blackbody fits this paper finds to be off by close to an order of magnitude in this case - if reprocessing outflows are common at early times, a systematic correction of that size would ripple through the inferred TDE luminosity function and energy budgets built on it. The finding is from one object, so it does not yet establish how common such outflows are this early, but it does establish that they exist before peak at all, which the authors frame as the reason prompt FUV spectroscopy - not just prompt photometry - has to be part of the standard early-time TDE follow-up.
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[2026-09-24] · src Arban, Complete Conservatory Method — 14 Characteristic Studies
Trumpet takes today's slot: three days since its last session on the 21st is the longest real gap of the three instruments right now, with piano having gone yesterday and alto the day before, continuing the alto/piano/trumpet cycle this rotation has held since mid-September. No. 11 follows straight on from No. 10, but it is a different kind of study. No. 10 was built on a repeat — the same two-bar phrase made to mean two different things across a D.C. No. 11 has no repeat at all: one continuous "Allegretto" pass, opening in C major with no key signature and moving through at least half a dozen key-signature changes before it ends plainly, including a swing to four flats at its own Più lento. The job today is reading those changes as they arrive rather than bracing for them.
5 minutes: the C major one-octave scale, ascending and descending in continuous sixteenths, quarter = 96, tongued lightly and evenly — then, with no pause and no re-set breath, the same scale a half step up in D-flat major, three times through alternating which direction starts. The point is rehearsing the exact reflex the etude demands cold: reorienting to a new key signature without a beat's hesitation.
The full page at quarter = 84 — a shade under No. 10's Allegro pace, matching what "Allegretto" actually asks for — three consecutive passes straight through, start to finish, with no stopping to reorient at a key change. Success criterion: on all three passes, the first note after every key-signature change lands correctly and in time, with no reached- for accidental — especially the turn into the Più lento's four flats, the widest single jump on the page.
The Più lento episode on its own, isolated from the surrounding Allegretto: its accented entrance and the phrase that follows. Play it once cold, then again deliberately slower than the surrounding tempo would suggest, leaning into that accent as an arrival rather than just another downbeat. A marked tempo change inside a technical study only earns its keep if it reads as a different idea, not a slowed-down version of the same one.
Stop the moment a key-signature change starts costing a beat of hesitation instead of landing clean — that hitch is fatigue substituting guesswork for reading, and a fourth pass built on top of it trains the guess, not the read.
[2026-09-24] · src —
hearJohn Coltrane — Giant Steps · Tidal · Spotify
Today's technical target is entirely about treating a key change as something to be ready for, not something to react to. "Giant Steps" states that problem in its most literal jazz form: harmony cycling through three key centers roughly every two bars, at a pace most tunes never approach, played by a soloist whose whole reputation on this track rests on making that cycle sound inevitable rather than hard. Listen for how little the time feel wavers at each turn — the harmonic ground moves constantly under the line, but the line never audibly braces for it, which is exactly the seamlessness today's success criterion is asking the etude's key changes to have.