The Large Hadron Collider, on the Franco-Swiss border near Geneva. Photo: Getty Images
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The Large Hadron Collider has made another exciting quantum discovery

Scientists working on one of the four experiments at the LHC have gathered enough evidence to confirm the existence of a four-quark particle.

Since the spectacular discovery of the Higgs boson in 2012, physicists at the Large Hadron Collider (LHC), the gigantic particle accelerator outside Geneva, have suffered a bit of a drought when it comes to finding new particles. In a welcome relief, the LHCb collaboration, who run one of four large experiments at the LHC, have announced one of the most genuinely exciting observations to come out of the 27km super-collider so far – an exotic particle that cannot be explained by current theories.

In the early 1930s physicists had a clean picture of the subatomic particles that make up our world. Every known atom has a tiny nucleus at its heart surrounded by a cloud of electrons, and each nucleus was made out of varying numbers of protons and neutrons. However, as the decades wore on a number of new, and somewhat unwelcome, particles were discovered, at first in detectors studying particles from outer space and later in particle-collider experiments.

By the 1950s, dozens of apparently elementary particles had been discovered, causing frustration among physicists who often brandish an inability to memorise a list of facts as a badge of honour. The famous physicist Enrico Fermi perhaps best expressed the mood of his colleagues in an infamous remark:

Young man, if I could remember the names of these particles, I would have been a botanist.”

Help came in the 1950s when physicists came up with a new model that explained most of these particles as being made up of a small number of truly elementary particles. Borrowing a line from James Joyce’s Finnegans Wake (a book that is even harder to understand than quantum field theory), Murray Gell-Mann dubbed these new particles “quarks”.

By the late 1960s the existence of quarks had been verified experimentally. We now know that there are six in total – the up, down, strange, charm, bottom and top quarks, along with six antiquarks (their anti-matter copies).

The quark model neatly explained all these peculiar particles. Protons, neutrons and many others besides are made of three quarks, belonging to a family known as baryons. Alternatively, a quark and an antiquark can pair up to form a meson.

Since then the quark model has been extremely successful, and is now a cornerstone of our understanding of particle physics. It was only at the turn of the millennium that some strange results started to suggest that the model might be incomplete. Until 2003 quarks had only been seen in twos or threes, but then a number of particles that looked like combinations of four quarks started to reveal themselves.

In 2008 the Belle Collaboration in Japan reported the observation of a new exotic particle – the unfortunately drably named Z(4430) (where for its negative charge). This has a mass that places it in a dense forest of charmonium states – particles that are made up of a charm quark and a charm antiquark. Crucially though, the Z is electrically charged whereas all charmonium states must be neutral, clearly marking it out as something unusual.

After a careful analysis of data from 25,000 decays of mesons resulting from more than 180 trillion collisions at the LHC in 2011 and 2012, the new announcement confirms the existence of Z(4430) with extremely high confidence. The particle was observed with an overwhelming significance of 13.9 sigma, well above the usual 5 sigma threshold required to declare a discovery. LHCb also went further than Belle by measuring the spin and parity of Z(4430), two quantum-mechanical properties that give a firm handle on the internal makeup of the particle.

The observation by LHCb is important because few physicists will take a result seriously until it has been seen by two independent experiments. This is why hundreds of millions of Euros were spent building two large detectors at the LHC. The observation of the Higgs boson by two independent teams, ATLAS and CMS, was what really convinced the scientific community that the particle was real.

This result is the clearest evidence yet of the existence of a tetraquark – a four-quark state, with the LHCb analysis suggesting that Z(4430) is most likely to be made of a charm, anti-charm, down and anti-up quark. Theorists are now able to add a whole new type of particle to the quark model and begin the hard work of trying to understand exactly how these four quarks are bound together.

Meanwhile, physicists working at the LHC experiments will continue to explore unmapped regions of the subatomic world, with the hope of turning up more members of this exotic new family. Now that we know that at least one is out there, it is very unlikely that Z(4430) is alone.The Conversation

Harry Cliff is affiliated with the University of Cambridge, CERN, the LHCb experiment.

This article was originally published on The Conversation. Read the original article.

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Move objects with your mind – telekinesis is coming to a human brain near you

If a user puts on the Neurable headset, they can move virtual objects with their thoughts. 

On 30 July, a blog post on Medium by Michael Thompson, the vice-president of Boston-based start-up Neurable, said his company had perfected a kind of technology which would be “redrawing the boundaries of human experience”. 

Neurable had just fulfilled the pipe dreams of science fiction enthusiasts and video game fanboys, according to Thompson – it had created a telekinetic EEG strap. In plain English, if a user puts on the Neurable headset, and plays a specially-designed virtual reality video game, they can move virtual objects with their thoughts. 

Madrid-based gaming company eStudioFuture collaborated with Neurable to create the game, Awakening. In it, the user breaks out of a government lab, battles robots and interacts with objects around them, all hands-free with Neurable's headset. Awakening debuted at SIGGRAPH, a computer graphics conference in Boston, where it was well received by consumers and investors alike.

The strap (or peripheral, as it’s referred to) works by modifying the industry standard headset of oversized goggles. Neurable's addition has a comb-like structure that reaches past your hair to make contact with the scalp, then detects brain activity via electroencephalogram (EEG) sensors. These detect specific kinds of neural signals. Thanks to a combination of machine-learning software and eye-tracking technology, all the user of the headset has to do is think the word “grab”, and that object will move – for example, throwing a box at the robot trying to stop you from breaking out of a government lab. 

The current conversation around virtual reality, and technologies like it, lurches between optimism and cynicism. Critics have highlighted the narrow range of uses that the current technology is aimed at (think fun facial filters on Snapchat). But after the debut of virtual reality headsets Oculus Rift and HTC Vive at 2016’s Game Developers conference, entrepreneurs are increasingly taking notice of virtual reality's potential to make everyday life more convenient.

Tech giants such as Microsoft, Facebook and Google have all been in on the game since as far back as 2014, when Facebook bought Oculus (of Oculus Rift). Then, in 2016, Nintendo and Niantic (an off-shoot from Google) launched Pokémon Go. One of Microsoft’s leading technical fellows, Alex Kipman, told Polygon that distinctions between virtual reality, augmented reality and mixed reality were arbitrary: "At the end of the day, it’s all on a continuum." 

Oculus’s Jason Rubin has emphasised the potential that VR has to make human life that much more interesting or efficient. Say that you're undergoing a home renovation – potentially, with VR technology, you could pop on your headset and see a hologram of your living room. You could move your virtual furniture around with minimal effort, and then do exactly the same in reality – in half the time and effort. IKEA already offers a similar service in store – imagine being able to do it yourself.

Any kind of experience that is in part virtual reality – from video games to online tours of holiday destinations to interactive displays at museums – will become much more immersive.

Microsoft’s Hololens is already being trialled at University College London Hospital, where students can study detailed holograms of organs, and patients can get an in-depth look at their insides projected in front of them (Hololens won’t be commercially available for a while.) Neurable's ambitions go beyond video games – its headset was designed by neuroscientists who had spent years working in neurotechnology. It offers the potential for important scientific and technological breakthroughs in areas such as prosthetic limbs. 

Whether it was a childhood obsession with Star Wars or out of sheer laziness, as a society, we remain fascinated by the thought of being able to move objects with our minds. But in actual realityVR and similar technologies bring with them a set of prickly questions.

Will students at well-funded schools be able to get a more in-depth look at topography in a geography lesson through VR headsets than their counterparts elsewhere? Would companies be able to maintain a grip on what people do in virtual reality, or would people eventually start to make their own (there are already plenty of DIY tutorials on the internet)? Will governments be able to regulate and monitor the use of insidious technology like augmented reality or mixed reality, and make sure that it doesn't become potentially harmful to minors or infringe on privacy rights? 

Worldwide spending on items such as virtual reality headsets and games is forecast to double every year until 2021, according to recent figures. Industry experts and innovators tend to agree that it remains extremely unlikely you’ll walk into someone examining a hologram on the street. All the same, VR technology like Neurable’s is slowly creeping into the fabric of our lived environment.