Tag Archives: Don Lincoln

The smallness of the Higgs mass (finding the Higgs boson)

As I noted last week (in my Dec. 6, 2011 posting), there was a big Dec. 13, 2011 announcement from CERN (European Laboratory for Particle Physics) about the Higgs boson. No, they haven’t found it but researchers believe they’ve discovered a hint of where it might be—this ‘hint’ has made international news.

For anyone who may have some questions about what exactly a Higgs boson is, here’s a video of “Fermilab scientist Don Lincoln [describing] the nature of the Higgs boson. Several large experimental groups are hot on the trail of this elusive subatomic particle which is thought to explain the origins of particle mass” (from the YouTube description),

Here’s a little more about why there’s so much excitement, from the Dec. 13, 2011 news item on Science Daily,

The Standard Model is the theory that physicists use to describe the behaviour of fundamental particles [the smallest discrete entities that make up matter and are not made up of smaller constituent bits of matter themselves] and the forces that act between them. It describes the ordinary matter from which we, and everything visible in the Universe, are made extremely well. Nevertheless, the Standard Model does not describe the 96% of the Universe that is invisible. One of the main goals of the LHC [Large Hadron Collider] research programme is to go beyond the Standard Model, and the Higgs boson could be the key.

A Standard Model Higgs boson would confirm a theory first put forward in the 1960s, but there are other possible forms the Higgs boson could take, linked to theories that go beyond the Standard Model. A Standard Model Higgs could still point the way to new physics, through subtleties in its behaviour that would only emerge after studying a large number of Higgs particle decays. A non-Standard Model Higgs, currently beyond the reach of the LHC experiments with data so far recorded, would immediately open the door to new physics, whereas the absence of a Standard Model Higgs would point strongly to new physics at the LHC’s full design energy, set to be achieved after 2014. Whether ATLAS [research group at CERN] and CMS [research group at CERN] show over the coming months that the Standard Model Higgs boson exists or not, the LHC programme is opening the way to new physics.

The search for the Higgs boson has been ongoing for some 40 or 50 years and this announcement points to a definitive answer as to its existence by late 2012.

Two groups at CERN have reported on the results of their search for the Higgs boson. From the Dec. 13, 2011 news item on physorg.com,

Two experiments at the Large Hadron Collider have nearly eliminated the space in which the Higgs boson could dwell, scientists announced in a seminar held at CERN today. However, the ATLAS and CMS experiments see modest excesses in their data that could soon uncover the famous missing piece of the physics puzzle.

The experiments revealed the latest results as part of their regular report to the CERN Council, which provides oversight for the laboratory near Geneva, Switzerland.

Theorists have predicted that some subatomic particles gain mass by interacting with other particles called Higgs bosons. The Higgs boson is the only undiscovered part of the Standard Model of physics, which describes the basic building blocks of matter and their interactions.

The experiments’ main conclusion is that the Standard Model Higgs boson, if it exists, is most likely to have a mass constrained to the range 116-130 GeV by the ATLAS experiment, and 115-127 GeV by CMS. Tantalising hints have been seen by both experiments in this mass region, but these are not yet strong enough to claim a discovery.

Scientists (Philip Schuster, Natalia Toro, and Andy Haas) at the Dec. 13, 2011 (9:30 am PST) Perimeter Institute webcast (What the Higgs is going on?), which took place a few hours after the CERN announcement, exhibited a lot of excitement liberally spiced with caution in regard to the announcement.  The webcast is available for viewing and if you’re wondering whether it’s suitable for you, here’s a description from the event webpage,

What is everything in the universe made of? What was the universe like billions of years ago?

These are eternal questions that humans have pondered throughout the ages. Today, we are on the verge of potentially making revolutionary breakthroughs in answering them.

The Large Hadron Collider (LHC) at CERN is a 27-kilometre long underground experiment located on the Swiss-French border near Geneva. It smashes subatomic particles together at vast speeds in an effort to learn more about the fundamental building blocks that make up everything around you. It is the biggest, most ambitious scientific experiment in human history.

On December 13, the LHC will announce its latest findings in its search for the last undiscovered particle in our current model of subatomic particles. This particle is the near-mythical ‘Higgs Boson’ — the particle thought to be involved in giving other particles their mass.

This educational event, geared towards high school students, teachers and the general public, will follow CERN’s announcement and discuss its findings and their background and implications in clear, accessible language.

You can view the webcast from here. The description of how scientists choose which events to measure and the process they use to define whether or not an event is significant adds to one’s appreciation of the work being done in these projects.

Jon Butterworth, a physicist who works at CERN and whose blog is one of the Guardian science blogs, wrote a limerick about it all in his Dec. 13, 2011 posting,

A physicist saw an enigma
And called to his mum “Flying pig, ma!”
She said “Flying pigs?
Next thing you’ll see the Higgs!”
He said “Nah, not until it’s five sigma!”

Five sigma is a measure of certainty. The current results have a 2.3 sigma, which is promising but the gold standard is five.

Here’s the live blog that Alok Jha, science correspondent for the Guardain, kept during the Dec. 13, 2011 announcement (excerpted from the live blog),

1.01pm: Cern’s live webcast has begun, but the seminar has yet to start. The expressions on some of the faces in the audience suggests Christmas is about to come early for the physics community.

1.02pm: Ok the seminar has started, but traffic to the webcast is obviously heavy, breaking up the transmission.

TRIUMF, Canada’s national laboratory for particle and nuclear physics, held a public seminar at 2:30 pm PST (Dec. 13, 2011) on their site at the University of British Columbia. They also have some information on their website about Canadian scientists who are involved in the CERN experiments ( from the Research Highlights page,  Physicists Smell but Don’t Yet Taste Higgs),

In a seminar held at CERN this morning and then repeated across Canada at multiple partnering institutions, the ATLAS and CMS experiments presented the status of their searches for the Standard Model Higgs boson. Finding this particle would snap in the last missing puzzle piece of the Standard Model that describes the universe at its most basic level. Tantalizing hints have been seen by both experiments in the same mass region, but these are not yet strong enough to claim a discovery. The main conclusion is that the Standard Model Higgs boson, if it exists, is most likely to have a mass in the range 115-130 GeV, excluding essentially all other hiding places.

“We are at a crossroads in our understanding of how energy gained mass and became matter in the early universe,” said Rob McPherson, spokesperson of the Canadian team working on the ATLAS project and a professor at the University of Victoria and a research scientist with the Institute of Particle Physics. “If these hints lead to a firm discovery over the coming year, we will be at the start of our investigation of the interactions that lie behind our current theories. If they are not confirmed, we will have to reject our present understanding, throw out our current theories, and start over. It is an extremely interesting time in particle physics.”

So there you have it. They think they observed something but they’re not sure, which makes for a very exciting time (they hope). While I’m not a scientist and cannot fully appreciate this moment, I can remember similar moments in my own work when something seems to be coming into focus. It isn’t my final result but it does hint at what is to come and gives me the resolve (giddy excitement for a few hours or days) I need to continue because a lot of what I do is slogging (I recognize the word play).

On a final note, it seems there was a minor crisis during the presentations in CERN. Lily Asquith, at the Argonne National Laboratory [Chicago, US] writes about it on Jon Butterworth’s blog (Guardian science blogs) in her Dec. 14, 2011 posting,

We have a large windowless meeting room at Argonne with an old-fashioned pull-down projector screen. When I walked in there yesterday morning for the CERN videolink I was greeted by 30-odd ashen-faced physicists. Oh lord, I thought, there has been a terrible accident. …

There stands Fabiola Gianotti [particle physicist in charge of the ATLAS experiment in CERN], our queen, looking fabulous and doing a typically faultless job of presenting a complicated and not-yet-conclusive measurement; taking the work of hundreds of nutty, stressed-out physicists and breathing sense into it.

But I hear only one thing as I walk the corridors of my lab and of the internet:

comic sans [the font Gianotti used for the text in her presentation]

- why‽

Do we need to add an additional systematic uncertainty to all our measurements based on this unwise choice of font? Are any of our results still valid? What does this mean for the speed of light?

Please do read the rest of Asquith’s very amusing piece. Who knew physicists are so concerned with fonts?

For the curious, here’s a sample of Comic Sans along with a history excerpt from its Wikipedia essay,

Microsoft designer Vincent Connare says that he began work on Comic Sans in October of 1994. Connare had already created a number of child-oriented fonts for various applications, so when he saw a beta version of Microsoft Bob that used Times New Roman in the word balloons of cartoon characters, he decided to create a new face based on the lettering style of comic books he had in his office, specifically The Dark Knight Returns (lettered by John Costanza) and Watchmen (lettered by Dave Gibbons).

So the font was originally designed for children and comic books, eh?