A 50-years-long hunt for the Higgs boson
The Higgs boson is the last particle of the Standard Model that has been discovered. Whilst it was postulated as early as in 1967, we had to wait until 2012 for being able to observe the boson in the data recorded at the Large Hadron Collider (the LHC) at CERN.
![](https://steemitimages.com/640x0/https://s18.postimg.org/vefzak8nt/higgs.jpg)
[image credits: Biswarup Ganguly]
However, the Higgs story is not that recent.
Particle physicists were aiming for discovering it since the second half of the last century.
With this post, I am browsing a little bit the Higgs story, from the early searches at the Large Electron-Positron collider times until its discovery five years ago.
Once again, I wanted to publish this article before the steemSTEM meetup inside the LHC. No problem, I am now one month late :D
THE HIGGS BOSON THEORY IN A NUTSHELL
I will not write a full post about the Higgs theory this time. I will instead refer to this recent post of mine and provide a condensed summary.
In a few words, the Standard Model of particle physics is a theory that works extremely well, and it agrees with thousands of measurements.
It is not wrong to tell that this is one of the most tested theories of all time.
![](https://steemitimages.com/640x0/https://steemimg.com/images/2016/08/13/FNAL_ESiegel11eb89.jpg)
[image credits: Fermilab]
However, the way in which the fundamental interactions are modeled (through some symmetries) does not allow for massive particles.
On the other hand, most particles are known to be massive. We have thus a problem here.
We could have concluded that the Standard Model was just wrong, but these concepts of symmetries worked extremely well. Too well for being directly sent to the graveyard.
The solution comes with the Brout-Englert-Higgs mechanism (tagging @muphy), which allows one both to keep the Standard Model and its underlying concepts and introducing elegantly the particle masses. If this is obscure and if you want to know more, please have a look here. As promised, no detail here ^^
WHERE TO SEARCH: THE HIGGS BOSON MASS ISSUE
So we have a mechanism allowing to keep the Standard almost untouched and introducing elegantly all particle masses. This mechanism however additionally predicts the existence of an extra particle, the Higgs boson, with well defined properties.
This was the missing link of the Standard Model that was searched for during the last decades.
After including the Brout-Englert-Higgs mechanism in the Standard Model, we end up with one extra free parameters in the theory: the mass of the Higgs boson. In a few words, this means that the Higgs boson mass can mostly be anything.
And by anything, I really mean anything. The Higgs could have been super-light or super-heavy. With an upper bound of about 1 TeV (1/13 of the current LHC collision energy) driven by theory.
![](https://steemitimages.com/640x0/https://s18.postimg.org/bvfzf94ih/Higgmass.png)
[image credits: homemade]
Whilst this leaves the door open for many options, this makes the Higgs particle hard to seek, as there are many corners where it could be hidden.
EPISODES 1, 2 AND 3: THE PRE-2012 ERA
Our hunt for the Higgs boson started in the 1990s with the Large Electron Positron collider, also known as the LEP, at CERN, but also with the Tevatron collider at Fermilab.
![](https://steemitimages.com/640x0/https://s18.postimg.org/vv5sb3w6x/lep.jpg)
[image credits: Geni]
The LEP collider was operating in the LHC tunnel (actually, it is the opposite: the LHC has been built inside the LEP tunnel) at the end of the last century.
By smashing accelerated electrons and positrons, this machine was capable to probe light Higgs options.
After slightly more than 10 years of running, all Higgs masses options between 0 and 114 GeV have been excluded.
Only 10% of all options have been probed...
From the 1980s to the end of 2011, another collider, the Tevatron at Fermilab, close to Chicago, was probing more massive options. This machine was smashing very energetic protons and very energetic antiprotons, at an energy equal to about 1/7 of the current LHC energy.
Once again, no discovery in the US (fun fact: no Standard Model boson has been discovered in the US).
And of course, the LHC was also running between 2009 and 2011. Here again, a big chunk of the options were found not possible because of data.
To make a 30 years-story short, we have this summary:
![](https://steemitimages.com/640x0/https://s18.postimg.org/62azbmbzd/Higgs_Hunting.png)
[image credits: homemade]
The LEP exclusion is shown in orange, the Tevatron exclusion is shown in green and the LHC exclusion is shown in blue.
Not even half of the options were covered in less 30 years…
THE DISCOVERY
![](https://steemitimages.com/640x0/https://steemimg.com/images/2016/09/03/HIG13001_Figure01.pngitok853kYykX4c2f4.png)
![](https://steemitimages.com/640x0/https://steemimg.com/images/2016/09/08/fig1a38fd.png)
[image credits: the CMS and ATLAS collaborations]
In 2012, things have changed as both the ATLAS and CMS collaborations of the LHC have observed something in the hole between the orange and blue area above. A Higgs boson! And one year later, a Nobel prize!
At this stage, it was a Higgs boson and not the Higgs boson. To be sure that the newly discovered guy is the Standard Model Higgs boson, its properties have to be measured precisely. All its properties.
ALL! And interestingly enough, the LHC will not be sufficient for that. For this reason, physicists are discussing today the next experimental move, i.e. what to do in 15-20 years from now! And Higgs physics is at the heart of these discussions.
SteemSTEM
SteemSTEM is a community-driven project that now runs on Steemit for more than a year. We seek to build a community of science lovers on Steemit and to promote well written/informative Science Technology Engineering and Mathematics (STEM) postings in order to make Steemit a place for fascinating STEM content.
More information can be found on the @steemstem blog and on our discord server and in our last project report.
I always enjoy the Fermi Labs videos on particle physics and other physics topics. This one called "Higgs Boson 2016" is worth a watch.
Coffee is indeed an important ingredient behind each great discovery :D
I suppose the video is good as I Don Lincoln is a very good physicist. I however can't watch it now. Even if I actually don't like videos that much (I prefer to read) I will try to have a look later :D
At least something undersandable becomes after this video, thanks :D
So my post wasn't understandable :'(
You're pregnant!
Strange. What have they discovered then? Nonstandard bosons?
Don't tell anyone about my pregnancy. I am actually XXYYXX :D
Fermions ^^
Fermions are not bad!
I am XXX (= always horny).
I will answer with a face-palm :D
I'm from Brazil and I'm so thrilled to read your WHOLE BLOG! I love science and astronomy in particular since I was a little kid. Thank you so much for your effort to support science no matter what.
I hope you do not mind if I quote you and inspire some posts of mine in yours.
Truly,
a fan.
Thanks for passing by! I don't mind if you get inspiration from my texts! Also, feel free to quote me anytime ^^
Back in 2010 when i first heard of the large hadron collider, i thought man thats some scary sci-fi stuff but the advancement in knowledge that behemoth has allowed us is super terrific! Higgs boson is just the tip of the iceburg. I personally believe that the suppresion of technology will fade as the older generations lose their control of the governance of the planet. As that happens we will have a scientific renaissance, it will be days of halcyon. I feel it. We have enough for everybody if we use science as the medium. In math we trust! Much love!
I am not too sure to follow you. I agree the Higgs is just one milestone on the path to understand how the universe works. So far so good. But for the rest, I am lost :D
Sorry about that, i mean up until this point our understanding of the universe has been based on theory. Higgs boson is a step away from belief systems and step towards factual systems. In the history of earth this has never happened. This breakthrough at cern is a big milestone to me, and i guess for all of science. What im trying to say is many of the people who have been in control of our resources were scared of technology and as time goes on and humanity uses tech to evolve We will see advancements in so many new areas. This blog got me really excited thats all. And yes i know there is a difference between scientific theory and A theory. But thats the kind of foundation our minds need. In math we trust.
Based on theory maybe, but a theory largely favored and confirmed by data.
For the rest, the problem is mostly related to pseudoscientific ideas that mostly spread through the internet and become mainstream, although they should have in principle never left the bar discussions... I don't know what the future will be...
I think an important mission of STEM is to educate people on the differences between science and pseudoscience. Unfortunately it takes a lot of time and patience, something most of us don't really have!
But we can be happy some of us have that time ^^
We must make time, and yes as @dizzyjay said, I am still getting into contact with people who want nothing to do with science even though they use it everyday. And this has everything to do with education. Which is failing its purpose in many countries.
Education and open mindedness. Accepting proofs, accepting that one can be wrong, and so on...
I think we need to keep a healthy fear of technology. When I was young I firmly believed technology held all our answers and I was cautioned by a wise old physics professor that technology can't solve everything. That was almost 30 years ago and though I'm still a total geek, I've come to understand what he was talking about. Technology is ultimately a tool, it's what we do with it that determines whether we advance or not.
The problem is not technology but its usage. As always: humans :D
I agree with you. We must be careful with what we do with what we develop. Always.
Are the any concrete plans yet as what the replacement for LHC will be? What would be the target capabilities?
There are several options and everything is discussed for the moment. The decision should be taken in the following year(s). I am personally working on the so-called FCC project, a 100km-long collider that will use the LHC as a pre-accelerator and collider protons at a collision energy equal to 7 times the LHC one.
Et le repos alors :)
Bah on a ecrit ensemble (voir ici).
Tu ne savais pas qu'ecrire sur steemit etait une activite de couple quand les enfants dormaient? [J'ai vraiment dit ca moi?] :D
lol ahahah ah bon on en apprend tous les jours sur Steemit décidement !!!
N'est-ce pas? :D
Lovely post sir really enjoyed it
Thanks! :)
Am also a lover of science related courses especially physics. Am waiting patiently for when to join the steemSTEM
You can join us anytime. Just pass by our discord chat :)
Actually if you look throug my blog you will find out i really want to be educated on steemit so for that reason i will follow you up cos you are good
Thanks a lot! It is really possible to get educated on steemit. There is a lot of information on many topics. If you are interested in STEM, I guess steemstem is for you :)
I once heard about the Higgs boson in a science documentary movie "Particle fever". Mention was also made of CERN and the LHC.
I found the trailer of the documentary
I know the movie. Some people I know are playing :)
Excellent report on the Higgs boson. Great discovery!. Thanks @lemouth for sharing this info. Regards.
My pleasure! :)