TL;DR
The 4σ result is still 4σ, but what changed is how much data Geneva can throw at it next — and whether five sigma now lives inside Run 3.
MSM Perspective
CERN's communications team has run the doubly-charmed-baryon discovery; the charm-penguin anomaly sits adjacent and unresolved.
X Perspective
Particle-physics Twitter is counting protons-per-fill: a 50-hour record fill delivered 366 inverse picobarns last week.
The anomaly survives the data. CERN's LHCb collaboration confirmed Wednesday that its 4σ charming-penguin result — a CP-violation measurement in D⁰ → KS⁰KS⁰ decays sitting at (1.86 ± 1.04 ± 0.41)% — holds as Run 3 statistics push past three times the 2018 data set [1]. Tuesday's first read named the threshold; the second-day read is about how fast the experiment can now reach it.
The denominator is where the news is. The upgraded LHCb detector replaced about ninety percent of its sensitive elements between Runs 2 and 3, swapped its hardware trigger for a fully software-based system, and now operates at five times the instantaneous luminosity of the earlier configuration [2]. April's record-breaking 50-hour fill delivered 366 inverse picobarns to LHCb alone — more than the entire 2015 data-taking year [3]. Run 3 is on track to clear 20 to 25 inverse femtobarns by its summer 2026 close.
The discovery threshold is 5σ. The CP-violation measurement in D⁰ → KS⁰KS⁰ — the most precise single-experiment result of its kind — needs the statistics to either confirm or fold the new-physics signal. Penguin diagrams, where loop-level virtual particles can carry beyond-Standard-Model effects, are the gates. The charm sector is where the Standard Model predicts CP asymmetries of order 10⁻⁴ or less; anything noticeably larger is a hint.
The doubly charmed Ξcc⁺ baryon, observed by LHCb in March at 7σ, was the upgrade's first headline. The charming-penguin question may yet be its second.
-- KENJI NAKAMURA, Tokyo
Sources & X Posts
News Sources