From Newsgroup: sci.physics

On 3/27/2026 3:19 PM, Jeroen Belleman wrote:

On 3/27/26 21:29, Martin Brown wrote:

On 26/03/2026 22:36, Jeroen Belleman wrote:

On 3/26/26 17:55, Martin Brown wrote:

On 26/03/2026 10:38, Jeroen Belleman wrote:

No, there isn't enough to blow anything up, not even close..

If you're interested, it's possible to visit CERN:
<https://visit.cern>. There may be waiting lists. It's
very sought after. CERN welcomes over a thousand visitors
daily.

What is the half life of an antiproton in a cryo Penning trap?

I'd have thought that preventing stray hydrogen atoms getting in
there would be nigh on impossible. Hydrogen even diffuses through
steel...

How many of the 92 will make it to the end of the journey?

Actually it's not too bad. The half-life of antiprotons in a
well-evacuated and cooled Penning trap is of the order of
months, once the hottest particles have escaped. Holding on
to antihydrogen is much harder, because you can't use electric
fields to confine it. The half-life of antihydrogen is in the
ballpark of a quarter of an hour.

We always had trouble getting the very last traces of hydrogen and
water out of ultra hard vacuum systems. Have things improved recently?

I'm surprised it is that good. I guess to some extent it is like the
globular star clusters in astronomy after a few hot ones get expelled
and the remaining ones settle down into a sort of equilibrium.

Gravitation binds remaining stars ever more tightly but for protons
you need an externally applied field to keep them in the middle of the
trap.

I don't have the detailed knowledge. I know that several of the
experiments using antiprotons can continue to function for a few
months after the accelerators are stopped. The vacuum is of the
order of 10nPa. (7.5e-11 torr)

I think the analogy with globular star clusters is a good one,
except that antiprotons repel rather than attract and indeed
externally applied electric fields are needed to keep them
trapped. They use Penning-Malmberg traps. Some experiments
inject electrons to further cool the antiprotons.

Annihilation requires interactions involving three particles,
which is rare because there are so few of them. I believe the
gravitational capture of one body by another also usually
requires the presence of a third.

Jeroen Belleman

This might interest you . . .

https://interestingengineering.com/science/scientists-observe-particles-emerging-from-nothing

World-first: Scientists observe particles emerging from nothing in collider
The STAR collaboration tracked rare quark-antiquark pairs created in
proton collisions, offering new evidence that empty space is not truly
empty.

By
Chris Young
Science
Apr 09, 2026 07:32 AM EST



Google News Preferred Source
A collision inside the STAR detector at the Relativistic Heavy Ion Collider.
A collision inside the STAR detector at the Relativistic Heavy Ion Collider. Brookhaven National Laboratory
Scientists at the Relativistic Heavy Ion Collider have observed
particles emerging directly from empty space for the first time,
confirming a long-standing prediction of quantum chromodynamics.

The discovery, reported by the STAR collaboration at Brookhaven National Laboratory in New York, involved high-energy proton collisions inside
the labrCOs Solenoidal Tracker detector. Researchers detected rare quark-antiquark pairs created from the vacuum itself rather than from
the colliding protons.

The finding provides the clearest evidence yet that matter can
materialize from what classical physics considers empty space. As such,
it could help provide an answer to one of the biggest mysteries in
physics: how particles acquire mass.

Measuring vacuum signatures
Quantum chromodynamics, the established theory of the strong force that
binds quarks inside protons and neutrons, holds that a perfect vacuum is
not empty. It contains constant fluctuations known as virtual particles, including short-lived quark-antiquark pairs.

Under ordinary conditions, these pairs appear and vanish almost
instantly. When sufficient energy is supplied, however, the theory
predicts they can become real particles with measurable mass.

In the STAR experiment, proton collisions generated a cascade of
particles. As free quarks cannot exist in isolation, quarks produced
from the vacuum immediately combine into composite particles called
hyperons.

The STAR team discovered key evidence in the form of the particlesrCO
quantum property of spin. Quarks and antiquarks born from the vacuum
carry correlated spinsrCoa shared alignment imprinted at creation. This correlation survived as the quarks formed hyperons and persisted even
after the hyperons decayed in less than a tenth of a billionth of a second.

Detection of these spin-aligned hyperons allowed the team to trace the quarksrCO origin to the vacuum rather than to the original collision
debris. rCLThis is the first time werCOve seen the whole process,rCY Zhoudunming You, a member of the STAR collaboration, explained in an
interview with New Scientist.

Shedding light on the origin of particle mass
The result has an important bearing on one of physicsrCO central puzzles:
the origin of particle mass.

Quantum chromodynamics predicts that quarks gain most of their mass
through interactions with the vacuum, yet the precise mechanism behind
this has remained unclear. The new observation provides a direct
experimental handle on those vacuum interactions.

It is worth noting that the results are not yet definitive, as
researchers must rule out other factors that may have caused the signal. Future runs at the Relativistic Heavy Ion Collider, and complementary experiments at other facilities, will aim to refine these findings.

Still, the new research opens a new experimental route to study vacuum properties and the mass-generation process predicted by quantum chromodynamics. The STAR collaborationrCOs work marks the first direct observation of vacuum-derived matter and sets the stage for further
tests of the theory at the energy frontier.
--- Synchronet 3.21f-Linux NewsLink 1.2