Prematura

Prematura, a lean herald-knight, strides one step ahead of his own glowing shadow, a loose cable dangling from his gauntlet.

The Physics

On 23 September 2011 the OPERA experiment reported muon neutrinos from CERN arriving at Gran Sasso, about 730 km away, (60.7 ± 6.9 ± 7.4) ns earlier than light would, an apparent faster-than-light result implying (v − c)/c = (2.48 ± 0.28 ± 0.30) × 10⁻⁵. In February 2012 the collaboration found two equipment faults: a badly connected optical-fibre connector on the GPS timing link, which added about 73 ns of delay and made the flight time look shorter, and a master-clock oscillator running slightly fast, which pushed the other way. ICARUS measured light-speed-consistent arrival times in March 2012, and on 8 June 2012 OPERA and the other Gran Sasso experiments reported results consistent with c.

δt = L/c − t_ν

(v − c)/c ≈ c δt / L

• δt: early arrival of the neutrinos relative to light (s)
• L: CERN-to-Gran Sasso baseline, about 730 km (m)
• c: speed of light, 299 792 458 m s⁻¹
• t_ν: measured neutrino time of flight (s)
• v: inferred neutrino speed (m s⁻¹)

With L ≈ 730 km the light travel time is about 2.4 ms, so 60 ns is a 2.5 × 10⁻⁵ effect. Supernova 1987A neutrinos had already bounded (v − c)/c far more tightly at lower energy. Sources: OPERA, arXiv:1109.4897; ICARUS, Phys. Lett. B 713, 17 (2012); OPERA, JHEP 10 (2012) 093; CERN press release, 23 Sep 2011 (update 8 Jun 2012).

Honest caveat: The neutrinos were never wrong; the measurement was. “It was the cable” is a simplification: two faults pulled in opposite directions, and the fibre was the bigger one.

In character

I arrived sixty nanoseconds early and the world held its breath. Then someone checked the plug. I was never ahead of the light, only ahead of the clock.

On the hoodie

Front: a fibre plug with a light gap and a dashed arrow. Front label: “OPERA FTL CLAIM · REFUTED 2012”. Back: Prematura in full pixel art with “BORN 23 SEP 2011 - DIED 8 JUN 2012” and “IT WAS THE CABLE.” Gildan 18500 Heavy Blend hoodie, Black, S to 5XL.

Part of the Ghost Particles That Were Wrong set with Sir Aetheron, Enrayne, Calorus, Diphantom, Thetarch. Browse all physics hoodies, more particle & nuclear physics designs, or the Deep Cuts.