RHIC hands baryon number to gluons; a magnetar lights a supernova; Cavendish hunts millicharged particles
Brookhaven collision data suggest a proton's identity rides on a Y-shaped gluon junction; an Einstein Probe X-ray flash points to a newborn magnetar; a Fermilab team proposes retuning Cavendish apparatus to sieve millicharged dark-matter candidates.
Science··Midday
RHIC collisions place baryon number on a gluon junction
The STAR detector at Brookhaven National Laboratory saw roughly twice as many baryons emerging perpendicular to the beam as models based on stopped quarks predict, using data collected at the Relativistic Heavy Ion Collider between 2000 and early 2026. Textbooks assign baryon number equally to a proton's three quarks; the study published in Science proposes the quantity may ride instead on a Y-shaped gluon junction. The authors argue the junction can be stopped more easily than the quarks, then draw new quarks from the vacuum to form a fresh baryon while the valence quarks continue down the beampipe. Comparing electric-charge redistribution showed too few stopped quarks to account for the observed baryon excess. RHIC finished taking data in early 2026.[1]
An X-ray flash signals a magnetar born in a supernova
The Einstein Probe satellite recorded a faint X-ray flash, EP250827b; Zwicky Transient Facility confirmed the signal 5.5 hours later when it found optical counterpart SN 2025wkm. The peer-reviewed analysis in The Astrophysical Journal Letters matched a hydrogen- and helium-free Type Ic-BL supernova with debris racing outward at roughly 40,000 km per second. Brightness held a plateau for about 20 days, the first such plateau among the four X-ray-flash supernovae the Einstein Probe has found. Radioactive decay alone could not explain the plateau, so the team fitted a newborn magnetar at the centre, estimating a magnetic field near 5×10¹⁴ gauss and a spin period of 1.9 ms as calculated. The magnetar is inferred from the light curve rather than directly detected.[2]
Cavendish apparatus could sieve millicharged particles
A team from Fermilab, Stanford and the University of Delaware calculated that hypothetical particles carrying a tiny fraction of the electron charge could be hunted with an updated Cavendish experiment. The peer-reviewed work in Physical Review Letters searches for deviations from Coulomb's and Gauss's laws inside an oscillating Faraday cage: ordinary charged particles cannot cross the cage, but millicharged ones may, leaving a measurable field. The calculation says such particles could be caught even if they make up less than one part in a trillion of dark matter, and projects sensitivity roughly three times beyond current or planned accelerator searches. Lead author Harikrishnan Ramani says the team is building a prototype with Kent Irwin's group at Stanford and expects results within a few years; no measurement exists yet.[3]
