Science_Illustrated_Australia_-_Issue70_2019

By Rolf Haugaard Nielsen

In every corner of the universe, Higgs bosons cooperate to give mass to all

atomic building blocks. Physicists aim to produce the particles in pairs to

reveal how their teamwork allowed matter to beat antimatter after the Big Bang.

Higgs boson pairs could

reveal the origin of all mass

Higgs pairs are

revealed by the four

quarks into which the

pairs often decay.

Accelerator is prepared for

the search for Higgs pairs

When the protons of the Large Hadron Collider particle

accelerator collide with an energy of 13 trillion electronvolts,

one Higgs pair will theoretically occur for every 2000 individual

Higgs bosons. The rarity has made it impossible yet to prove pair

production. But in 2016, the large ATLAS detector found a

possible Higgs pair, providing physicists with an idea of what to

look for. In order to intensify the search, the LHC has been

improved twice. Before the next experiments in 2021, the

detectors are being upgraded to enable them to find more

Higgs pairs. The accelerator itself will be adjusted in 2024-2025,

boosting the collision rate to 10 billion proton collisions/second

and improving the chances of producing a Higgs pair.

A

network of Higgs bosons

encloses the entire universe,

from the remotest of galaxies

to the innermost cells of

humans. Although it is

neither visible nor directly measurable, the

Higgs field is certainly stable – otherwise

Earth would become weightless at regular

intervals. Since the beginning of the

universe, the Higgs field has been constantly

active to ensure that all atom building

blocks – such as quarks and electrons – have

mass. The question of how this mass field

works, however, has tormented physicists

ever since the Higgs particle materialised for

the first time in their detector in 2012.

CERN physicists now aim to reveal the

secret of the field by producing Higgs boson

pairs, and studying how they react with each

other. The production will begin when an

updated version of the Large Hadron Collider

(LHC) is completed in 2021 after two years of

upgrading. By then, physicists hope to be

able to solve the mystery of why everything

has mass. And further, the Higgs pairs might

allow us a peek into the world of dark matter.

Pairs keep Higgs field active

Although nobody has yet studied the nature

of the Higgs field, physicists have an idea of

how the network works, based on existing

physics theories. The Higgs field provides the

particles with energy and, according to Albert

Einstein’s famous equation E = mc2, energy

equals mass.

The Higgs field can be compared to an

electric field between positively and negati-

vely charged electrodes, but with one crucial

difference: an electric field disappears when

the voltage difference between the electrodes

is neutralised. The Higgs mass field, however,

is active throughout the universe eternally,

because the Higgs bosons constantly react

with each other. The reactions maintain the

charge of the field, providing elementary

particles with their mass.

Each building block of atoms with mass

interacts differently with the Higgs field.

Quarks interact intensely with the field, and

so are relatively heavy. Electrons interact

more weakly, so these particles are lighter.

But it is unknown how the Higgs boson

reactions keep the field active all the time.

The LHC will try to find the answer.

Frequent decay is a clue

While the LHC has probably already produced

around 1000 Higgs boson pairs, they are so

rare that they drown under the noise of the

showers of particles produced in trillions of

collisions since the experiments began in

2010. But a new discovery boosts optimism.
      When physicists discovered the Higgs
      boson in 2012, it was revealed by the rare
      decay into two high-energy gamma photons.
      But last year, physicists observed a Higgs
      boson that decayed into two heavy bottom
      quarks, which can be produced only in
      high-energy proton collisions such as in

Quark 1

Collision

Protons

Quark 3

ATL

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RIM
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Quark 2
Quark 4