econintersect.com
       
  

FREE NEWSLETTER: Econintersect sends a nightly newsletter highlighting news events of the day, and providing a summary of new articles posted on the website. Econintersect will not sell or pass your email address to others per our privacy policy. You can cancel this subscription at any time by selecting the unsubscribing link in the footer of each email.



posted on 24 December 2016

Explainer: What Is Antimatter?

from The Conversation

-- this post authored by Roger Jones, Lancaster University

Antimatter was one of the most exciting physics discoveries of the 20th century. Picked up by fiction writers such as Dan Brown, many people think of it as an “out there" theoretical idea - unaware that it is actually being produced every day. What’s more, research on antimatter is actually helping us to understand how the universe works.

Antimatter is a material composed of so-called antiparticles. It is believed that every particle we know of has an antimatter companion that is virtually identical to itself, but with the opposite charge. For example, an electron has a negative charge. But its antiparticle, called a positron, has the same mass but a positive charge. When a particle and its antiparticle meet, they annihilate each other - disappearing in a burst of light.

Such particles were first predicted by British physicist Paul Dirac when he was trying to combine the two great ideas of early modern physics: relativity and quantum mechanics. Previously, scientists were stumped by the fact that it seemed to predict that particles could have energies lower than when they were at “rest" (ie pretty much doing nothing). This seemed impossible at the time, as it meant that energies could be negative.

Dirac, however, accepted that the equations were telling him that particles are really filling a whole “sea" of these lower energies - a sea that had so far been invisible to physicists as they were only looking “above the surface". He envisioned that all of the “normal" energy levels that exist are accounted for by “normal" particles. However, when a particle jumps up from a lower energy state, it appears as a normal particle but leaves a “hole", which appears to us as a strange, mirror-image particle - antimatter.

Despite initial scepticism, examples of these particle-antiparticle pairs were soon found. For example, they are produced when cosmic rays hit the Earth’s atmosphere. There is even evidence that the energy in thunderstorms produces anti-electrons, called positrons. These are also produced in some radioactive decays, a process used in many hospitals in Positron Emission Tomography (PET) scanners, which allow precise imaging within human bodies. Nowadays, experiments at the Large Hadron Collider (LHC) can produce matter and antimatter, too.

Matter-antimatter mystery

Physics predicts that matter and antimatter must be created in almost equal quantities, and that this would have been the case during the Big Bang. What’s more, it is predicted that the laws of physics should be the same if a particle is interchanged with its antiparticle - a relationship known as CP symmetry. However, the universe we see doesn’t seem to obey these rules. It is almost entirely made of matter, so where did all the antimatter go? It is one of the biggest mysteries in physics to date.

Experimental area at CERN including the alpha experiment. Mikkel D. Lund/wikimeda, CC BY-SA

Experiments have shown that some radioactive decay processes do not produce an equal amount of antiparticles and particles. But it is not enough to explain the disparity between amounts of matter and antimatter in the universe. Consequently, physicists such as myself at the LHC, on ATLAS, CMS and LHCb, and others doing experiments with neutrinos such as T2K in Japan, are looking for other processes that could explain the puzzle.

Other groups of physicists such as the Alpha Collaboration at CERN are working at much lower energies to see if the properties of antimatter really are the mirror of their matter partners. Their latest results show that an anti-hydrogen atom (made up of an anti-proton and an anti-electron, or positron) is electrically neutral to an accuracy of less than one billionth of the charge of an electron. Combined with other measurements, this implies that the positron is equal and opposite to the charge of the electron to better than one part in a billion - confirming what is expected of antimatter.

However, a great many mysteries remain. Experiments are also investigating whether gravity affects antimatter in the same way that it affects matter. If these exact symmetries are shown to be broken, it will require a fundamental revision of our ideas about physics, affecting not only particle physics but also our understanding of gravity and relativity.

In this way, antimatter experiments are allowing us to put our understanding of the fundamental workings of the universe to new and exciting tests. Who knows what we will find?

The ConversationRoger Jones, Professor of Physics, Head of Department, Lancaster University

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

>>>>> Scroll down to view and make comments <<<<<<

Click here for Historical News Post Listing










Make a Comment

Econintersect wants your comments, data and opinion on the articles posted.  As the internet is a "war zone" of trolls, hackers and spammers - Econintersect must balance its defences against ease of commenting.  We have joined with Livefyre to manage our comment streams.

To comment, using Livefyre just click the "Sign In" button at the top-left corner of the comment box below. You can create a commenting account using your favorite social network such as Twitter, Facebook, Google+, LinkedIn or Open ID - or open a Livefyre account using your email address.



You can also comment using Facebook directly using he comment block below.





Econintersect Contributors


search_box

Print this page or create a PDF file of this page
Print Friendly and PDF


The growing use of ad blocking software is creating a shortfall in covering our fixed expenses. Please consider a donation to Econintersect to allow continuing output of quality and balanced financial and economic news and analysis.


Take a look at what is going on inside of Econintersect.com
Main Home
Analysis Blog
Democratic Development Lowers the Cost of Credit
Is Growing Household Debt An Economic Counter-Dynamic?
News Blog
Durable Goods New Orders Improved in January 2017
China's Continuing Credit Boom
Infographic Of The Day: Ten Interview Questions That Make You Sound Dumb
Early Headlines: Asia Stocks Down, Oil Up, Dollar And Gold Steady, UK Inflation, 'Moonlight' Wins Oscar, LSE Merger May Be Off, Greek Banks, India Going Green And More
Most Read Articles Last Week Ending 25 February
How British Businesses Helped The Confederacy Fight The American Civil War
Where You Can Surf A Lot For A Little In The EU
'I Can Live With Either One': Palestine, Israel And The Two-state Solution
Where Snapchat's Users Come From
What We Read Today 26 February 2017
INAUGURATION DAY: A Bad Lip Reading Of Donald Trump's Inauguration
Did The Dodd-Frank Act Make The Financial System Safer?
A Close Look At The Decline Of Homeownership - Part Five Of Five
Investing Blog
The Week Ahead: Reality And Stock Prices
Snapchat Still Has Some Growing Up To Do
Opinion Blog
What Do You Call A Lie Constructed From Other Lies?
Why Winning The French Presidential Election Could Be A Poisoned Chalice
Precious Metals Blog
Deflation And Gold: A Contrarian View
Live Markets
27Feb2017 Pre-Market Commentary: Wall Street To Open Down And Flat, Crude Prices Climb, US Dollar Steady, Trump's Speech Tomorrow Could End Market Rally
Amazon Books & More






.... and keep up with economic news using our dynamic economic newspapers with the largest international coverage on the internet
Asia / Pacific
Europe
Middle East / Africa
Americas
USA Government





























 navigate econintersect.com

Blogs

Analysis Blog
News Blog
Investing Blog
Opinion Blog
Precious Metals Blog
Markets Blog
Video of the Day
Weather

Newspapers

Asia / Pacific
Europe
Middle East / Africa
Americas
USA Government
     

RSS Feeds / Social Media

Combined Econintersect Feed
Google+
Facebook
Twitter
Digg

Free Newsletter

Marketplace - Books & More

Economic Forecast

Content Contribution

Contact

About

  Top Economics Site

Investing.com Contributor TalkMarkets Contributor Finance Blogs Free PageRank Checker Active Search Results Google+

This Web Page by Steven Hansen ---- Copyright 2010 - 2017 Econintersect LLC - all rights reserved