Australian Science Illustrated – Issue 51 2017

34 | SCIENCE ILLUSTRATED

Scientists have discovered an unknown particle by firing a beam of protons at

lithium foil. The new particle could be the carrier of the fifth force of nature.

Invisible light reveals

the fifth force of nature

Proton

Dark photon

Electron

Positron

Lithium-7 foil

Beryllium-8

A beam of tiny

nuclear particles,

protons, is fired at

lithium-7 foil.

1

The nuclei of the

lithium atoms are

hit, and the extra

proton converts them

into beryllium-8, whose

nucleus is unstable.

2

The beryllium-8

nucleus decays,

because the nuclear forces

are not strong enough to

hold the unstable nucleus

together. The decay emits

radiation in the shape of

electron and positron pairs.

3

photon is something as mysterious as
dark, invisible light.
According to the Hungarian theory, the
invisible light is difficult to detect, as it very
rarely reacts with ordinary atoms. However,
the light can reveal itself via interaction with
the weak nuclear force, which triggers a
specific type of radioactive decay.
An atom decays, when its nucleus becomes
so unstable that the strong and weak nuclear
forces can no longer hold it together. When the
atomic nucleus decays, it emits radiation as

different particles depending on the type of

decay. Physicists produced unstable

beryllium-8 by firing a beam of protons at

lithium foil. The material decays very fast, and

in the process, the radioactive atom emits an

electron and a positron, which is the antiparticle

of the electron.

All particles have antiparticles with the

exact same mass and characteristics, but

with the opposite electric charge. So, an

electron is always negatively charged,

whereas its antiparticle, the positron, is

always positively charged.

According to well-established physics

theories, the electron and positron pairs fly in

the same direction as the proton beam that hit

the foil. Most of the particles behaved exactly

as predicted, but the Hungarian physicists

discovered two beams of electrons and

positrons that moved in other directions. The

deviation indicated that the decay produced

unknown particles that sped to the sides,

before, one split second later, they were also

converted into electrons and positrons.

THE DARK ELECTROMAGNETIC FORCE

NORMAL

Most pairs speed

directly through the foil

in the same direction as

the proton beam, just

like scientists expected.

DEVIATION

Two beams speed to

the sides. According to

scientists, the deviation

is due to the beryllium

atoms emitting dark

photons.

5

THE UNIVERSE PHYSICS