Large Hadron Collider all fired up again

Scientists herald a new frontier in physics

The Large Hadron Collider (LHC) has been fired up to start delivering physics data for the first time in 27 months, meaning experiments can resume at the world’s largest particle accelerator.

It follows more than two years of maintenance and repair as well as several months of recommissioning.

The experiments are set to take data at the unprecedented energy of 13 tera-electronvolts (TeV) — almost double the collision energy of the LHC’s first, three-year run.

It is hoped this will mark the start of season two at the LHC, opening the way to new frontiers in physics.

READ MORE: Everything you need to know about the Large Hadron Collider and what it's doing right now

Due to a software issue the first beams sent yesterday morning had to be stopped.

The €5bn LHC, the most powerful atom-smasher ever built, was restarted in April after a two-year upgrade.

Last month scientists from the European Organisation for Nuclear Research (Cern) achieved test collisions between protons — the “hearts” of atoms — at 13 TeV for the first time.

Two beams of particles travelling a whisker below the speed of light are sent flying in opposite directions through 26.8km of circular tunnels beneath the Swiss-French border.

The beam energy has only now been ramped up to its operating level of 13 TeV, almost twice the power used to uncover the Higgs boson two years ago.

The LHC team astounded the world with the discovery of the elementary particle that gives other particles mass, which had eluded detection for nearly 50 years.

With the ability to tap into higher energy, the scientists hope to explore mysterious realms of “new physics” that could yield evidence of hidden extra dimensions and dark matter.

Dark matter is the invisible, undetectable “stuff” that makes up 84% of material in the universe and binds galaxies together, yet whose nature is unknown.

Protons race around the LHC beam tunnels at 3m per second below the speed of light. The energy released when they collide is used to spark the creation of new particles.

Einstein’s equation E=MC² showed that energy and mass are interchangeable. Upping the energy levels at the LHC increases the chances of some of it being converted to previously undetected, heavier particles — possibly including dark matter.

The particle collisions take place in four detectors arranged around the beam ring known as Atlas, CMS, Alice, and LHCb.

Atlas team leader Professor David Charlton, from the University of Birmingham, said: “We’re heading for unexplored territory. It’s going to be a new era for science.”

As well as searching for dark matter, LHC scientists hope to create more and possibly different strains of Higgs boson, investigate anti-matter, and test the theory of “supersymmetry” which predicts that every known particle has a more massive hidden partner.

Supersymmetry seeks to fill gaps in the Standard Model, the all-encompassing blueprint of particles and forces in the universe that has been in place since the 1970s.

Q&A: The heart of the matter ... at lightening speed

After discovering Higgs boson with their first run, physicists are hoping to make more breakthroughs with almost double the collision energy. But what is the Large Hadron Collider and what exactly is going on inside it?

What is the Large Hadron Collider?

It is a giant machine about the size of the London Underground’s Circle line. It is designed to smash subatomic particles called protons into each other at velocities very close to the speed of light.

Beams of protons are shot in opposite directions through the ring-shaped 27km tunnel buried underneath the border between Switzerland and France, near Geneva.

The name refers to the family of particles called hadrons, which includes protons and neutrons, and is derived from the Greek word ‘adros’ meaning ‘bulky’.

At a temperature colder than deep outer space, it contains iron, steel and the all-important superconducting coils, making it the world’s largest fridge.

The data recorded by each of the big experiments at the Large Hadron Collider will be enough to fill around 100,000 dual-layer single-sided DVDs every year.

Why are the particles being made to collide?

Scientists believe these proton collisions will take them further back in time and allow them to peer deeper into the heart of matter than ever before.

In March 2013, physicists discovered Higgs boson, an elementary particle that gives other particles mass, which had eluded detection for nearly 50 years.

It is hoped that with the higher energy in the second run, scientists will be able to explore mysterious realms of ‘new physics’ that could yield evidence of hidden extra dimensions and dark matter. They also hope to create more and possibly different strains of Higgs boson, investigate anti-matter, and test the theory of ‘super- symmetry’.

What are the beams that are being collided?

Beams are made of ‘trains’ of proton bunches moving at almost the speed of light around the ring of the Large Hadron Collider. These ‘bunch trains’ circulate in opposite directions, guided by powerful magnets.

A beam might circulate for 10 hours, travelling more than 9.5bn kilometres, enough to get to the planet Neptune and back.

At near light-speed, a proton in the Large Hadron Collider will make 11,245 circuits every second.

Where do the protons that are accelerated come from?

They are standard hydrogen.