Viewing: Blog Posts Tagged with: CMS, Most Recent at Top [Help]
Results 1 - 4 of 4
Blog: Kevin McNamee: Children's Author (Login to Add to MyJacketFlap)
JacketFlap tags: writing, website, CMS, Joomla, content management system, Add a tag
Blog: OUPblog (Login to Add to MyJacketFlap)
JacketFlap tags: atlas, CMS, LHC, CERN, Higgs, baggott, *Featured, Physics & Chemistry, jim baggott, Higgs Boson, tevatron, Science & Medicine, Standard model, boson, Invention and Discovery of the ‘God Particle’, of higgs, particle’, particle’ and, particle’ with, fermilab, bottom quark, decay pathways, fermions, Jon Butterworth, mass value, matter particles, particle collisions, tau lepton, cern’s large, Add a tag
We’re celebrating the release of Higgs: The Invention and Discovery of the ‘God Particle’ with a series of posts by science writer Jim Baggott over the week to explain some of the mysteries of the Higgs boson. Read the previous posts: “What is the Higgs boson?”, “Why is the Higgs boson called the ‘god particle’?”, “Is the particle recently discovered at CERN’s LHC the Higgs boson?”, and “How does the Higgs mechanism create mass?”
By Jim Baggott
The 4 July discovery announcement makes it clear that the new particle is consistent with the long-sought Higgs boson. The next step is therefore reasonably obvious. Physicists involved in the ATLAS and CMS detector collaborations at the LHC will be keen to push ahead and fully characterize the new particle. They will want to know if this is indeed the Higgs boson.
How can they tell?
I mentioned in the third post in this series that the physicists at Fermilab’s Tevatron and CERN’s LHC have been searching for the Higgs boson by looking for the tell-tale products of its different predicted decay pathways. The current standard model of particle physics is used to predict the rates of production of the Higgs boson in high-energy particle collisions and the rates of its various decay modes. After subtracting the ‘background’ that arises from all the other ways in which the decay products can be produced, the physicists are left with an excess of events that can be ascribed to Higgs boson decays.
Now that we know the new particle has a mass of between 125-126 billion electron-volts (equivalent to the mass of about 134 protons), both the calculations and the experiments can be focused tightly on this specific mass value.
So far, excess events have been observed for three important decay pathways. These involve the decay of the Higgs boson to two photons ( H → γγ), two Z bosons (H → ZZ → ι+ι-ι+ι-) and two W particles (H → W+W- → ι+υ ι-υ). You will notice that these pathways all involve the production of bosons. This should come as no real surprise, as the Higgs field is responsible for breaking the symmetry between the weak and electromagnetic forces, giving mass to the W and Z particles and leaving the photon massless.
The decay rates to these three pathways are broadly as predicted by the standard model. There is an observed enhancement in the rate of decay to two photons compared to predictions, but this may be the result of statistical fluctuations. Further data on this pathway will determine whether or not there’s a problem (or maybe a clue to some new physics) in this channel.
But the Higgs field is also involved in giving mass to fermions (matter particles, such as electrons and quarks). The Higgs boson is therefore also predicted to decay into fermions, specifically very large massive fermions such as bottom and anti-bottom quarks, and tau and anti-tau leptons. Bottom quarks and tau leptons (heavy versions of the electron) are third-generation matter particles with masses respectively of about 4.2 billion electron volts (about 4 and a half proton masses) and 1.8 billion electron volts (about 1.9 proton masses).
These decay pathways are a little more problematic. The backgrounds from other processes are more significant and considerably more data are required to discriminate the background from genuine Higgs decay events. The decay to bottom and anti-bottom quarks was studied at the Tevatron before it was shut down earlier this year. But the collider had insufficient collision energy and luminosity (a measure of the number of collisions that the particle beams can produce) to enable independent discovery of the Higgs boson.
ATLAS physicist Jon Butterworth, who writes a blog for the British newspaper The Guardian, recently gave his assessment:
If and when we see the Higgs decaying in these two [fermion] channels at roughly the predicted rates, I will probably start calling this new boson the Higgs rather than a Higgs. It won’t prove it is exactly the Standard Model Higgs boson of course, and looking for subtle differences will be very interesting. But it will be close enough to justify [calling it] the definite article.
When will this happen? This is hard to judge, but perhaps we will have an answer by the end of this year.
Jim Baggott is author of Higgs: The Invention and Discovery of the ‘God Particle’ and a freelance science writer. He was a lecturer in chemistry at the University of Reading but left to pursue a business career, where he first worked with Shell International Petroleum Company and then as an independent business consultant and trainer. His many books include Atomic: The First War of Physics (Icon, 2009), Beyond Measure: Modern Physics, Philosophy and the Meaning of Quantum Theory (OUP, 2003), A Beginner’s Guide to Reality (Penguin, 2005), and A Quantum Story: A History in 40 Moments (OUP, 2010). Read his previous blog posts.
On 4 July 2012, scientists at CERN’s Large Hadron Collider (LHC) facility in Geneva announced the discovery of a new elementary particle they believe is consistent with the long-sought Higgs boson, or ‘god particle’. Our understanding of the fundamental nature of matter — everything in our visible universe and everything we are — is about to take a giant leap forward. So, what is the Higgs boson and why is it so important? What role does it play in the structure of material substance? We’re celebrating the release of Higgs: The Invention and Discovery of the ‘God Particle’ with a series of posts by science writer Jim Baggott over the week to explain some of the mysteries of the Higgs. Read the previous posts: “What is the Higgs boson?”,“Why is the Higgs boson called the ‘god particle’?”, “Is the particle recently discovered at CERN’s LHC the Higgs boson?”, and “How does the Higgs mechanism create mass?”
Subscribe to the OUPblog via email or RSS.
Subscribe to only physics and chemistry articles on the OUPblog via email or RSS.
View more about this book on the
Blog: Christine Garner Illustration (Login to Add to MyJacketFlap)
JacketFlap tags: resources, Life in general, WordPress, CMS, plugins, Add a tag
This is a little update to what I’ve been doing in the past months involving art, WordPress, coding and life in general. There’s a few links to useful things I’ve found recently as well.
I now have a new part time job which I am enjoying very much: it’s easily the best job I’ve ever had, and am also in the process of getting ready to move to another area of the country to be with my fiancé. Lets just say life is looking a lot better than it was 2 years ago. I may write a post/essay on that one day if I have nothing better to do with my time (perhaps not then).
I took up my martial arts and yoga again over the past 2 years and sorted a few things out with my confidence and fitness in general which hopefully will one day reflect on my artwork. I can nearly kick my head again, but not quite.
I’ve also been working since last year on a WordPress CMS website project and a picture book project to keep my skills up and learn new things. I will go into more detail as the projects develop later in the year.
Here’s a few useful things I found on the inter-web recently for you as you’ve read this far:
Useful WordPress plugins
PHPEnkoder (automatically encrypts emails on web page to stop email spam)
WP-Cycle (J Query image slide show)
Members (I’m keeping my eye on this one, looks very promising for user management)
Free Software
Backup tool, FreeFileSync (useful for flash drives and secondary hard drive backup)
Password manager, KeePass
Blog: librarian.net (Login to Add to MyJacketFlap)
JacketFlap tags: software, hi, upgrade, wordpress, cms, Add a tag
Hi — I just upgraded my WordPress install and along with it, removed some old crusty plugins that I don’t think I was using anymore. If you come across something that is broken or working worse than it was this morning, please drop me a line or a comment and let me know. Thank you.