Picture 1: Connections between the elementary particles and different decay path of the elementary particles [1]
The search for the Higgs Boson
In 1979, physicists Sheldon Glashow, Abdus Salam and Steven Weinberg had received the Nobel Prize in Physics for forming the basic of the electroweak interaction of the elementary particles. They were curious about why do some of the elementary particle like the W, Z Boson, Electrons and all the Quarks carries different mass but other particles like the Gluon and Photon doesn’t carry any mass at all. They propose there should be an extra particle introducing electroweak interactions to these particles which depending on how much the new particle react with the elementary particles, will affects the amount of mass each particle has.
The discovery of this “extra particle” explained that because Photon and Gluon does not react with this particle, it will not pick up any mass, which others will have different mass depending on how much they reacts with this particle. Top Quark reacts strongly with it so it gained more mass than other.
The “extra particle” is later called the Higgs Boson. Which CERN (The European Organization for Nuclear Research) had announced that the existence of a particle that is similar to the Higgs Boson had been experimentally established on 4th of July, 2012.
How does the higgs field give mass to other particles
the Higgs Field/ Higgs mechanism
The Higgs mechanism is the regeneration of masses in the W and Z Boson specifically in the standard model. This mechanism is proposed by Philip Warren Anderson in 1962. A simple way of describing how the Higgs Mechanism is illustrated with the following pictures:
[2]
Imagine there is a party and the room is filled with people. Everyone is chatting with each other when all the sudden a celebrity (ex-prime- Minister is used in Prof. David J. Miller’s version) is enter the room and the people closer to the celebrity immediately surround him. As he is trying to get from one end of the room to the other end, more people goes closer towards him, but the speed of the celebrity walking remains the same.
The Higgs Mechanism behaves in similar ways, but instead of the celebrity, we have an elementary particle going through the Higgs field in a constant speed. The Higgs Boson is gaining more and more momentum as it is going through the Higgs field, but because the speed is constant and: Momentum = mass x velocity
Therefore the mass of the particle is the value that is changing, and we can conclude that mass is gaining by particles in the Higgs field if this theory is proven to be correct.
But what actually is the Higgs field? They are the “empty” spaces between particles that also give the particles masses. (Some scientists say that the Higgs field is the Dark matters in the Universe). According to the Higgs Mechanism, the Higgs Field is all around the Universe. When elementary particles interacts with the field, sometimes they will pick up mass from the field during the interaction, sometimes they form a side product, the Higgs Boson.
the mass of the Higgs boson
Higgs Boson itself also has its own mass; however its mass is actually not a constant like all the other elementary particles. It is dependent on how much the energy is used to create the Higgs Boson; this behavior could be described by the following equation:
V(x) =2x4-(1-T2) x2+
[4]
V, the potential energy is the stored energy for creating the Higgs Boson. T is the collision energy being used to create the Higgs Boson and x being the mass of the Higgs Boson. It is described that the Higgs field that is transmitted by the Higgs Boson is similar to the electromagnetic field that is transmitted by photon. Higgs boson is excluded between about 140 GeV and 500 GeV by researches, and the researches also concluded that the most likely region for the Higgs mass to be is between about 115 GeV and 140 GeV.
But how do we know that the Higgs Boson has mass? Couldn’t Higgs Boson be massless like Photon and Gluon? Prof. David J. Miller, University College London had explained this in a simple and clean way.
“Consider a rumour passing through our room full of uniformly spread political workers. Those near the door hear of it first and cluster together to get the details, then they turn and move closer to their next neighbours who want to know about it too. A wave of clustering passes through the room. It may spread out to all the corners, or it may form a compact bunch which carries the news along a line of workers from the door to some dignitary at the other side of the room. Since the information is carried by clusters of people, and since it was clustering which gave extra mass to the ex-Prime Minister, then the rumour-carrying clusters also have mass.” [2]
This example explains why the “cluster” (the Higgs Boson) should have mass while the “ex-Prime-Minister” (the elementary particle) gains more mass in the Higgs field. So if we can prove that Higgs Boson exists, we can prove the theory of the Higgs mechanism and the Higgs field is true.
[2]
the Decay of the Higgs Boson
decay
It is almost impossible to detect the Higgs Boson mainly due to the fact that Higgs Boson tends to decay immediately, other reasons being the detector couldn’t detect it fast enough. So in order to prove or disprove the existence of the Higgs Boson, the LHC (Large Hadron Collider) will be looking for the decayed particles of the Higgs Boson. However, there is no constant decay, the decay of the Higgs Boson really depends on how much mass the Higgs Boson has, different masses of the Higgs Boson will lead the Higgs Boson to decay into different elementary particles.
When the Higgs Boson has a mass of 80 – 130 GeV/c2, the decay of a pair of bottom quarks will be dominant: _
H → bb
[3]
When the Higgs Boson has a mass of 130 – 180 GeV/c2, the decay of a pair of W Boson will be dominant:
H→ W+ W-
The assumption is that Higgs Boson has no charge that is the reason why scientist predicts to have a positive and negative W Boson to balance the charge out. After the decay of Higgs boson to the W Bosons, W Boson will decay to either Leptons or Quarks:
[3]
References:
Higgs Boson Particle Quantum Integer Radioactive Decay Numbers [1]
This is just a website I got the picture of the decay path from. There is not much information on it but I provide a really nice and easy-to-understand picture for me to use.
http://theideagirlsays.wordpress.com/2012/08/17/higgs-boson-particle-quantum-integer-radioactive-decay-numbers-chromodynamics-qcd-weak-interactions-5g-wow-seti/elementary-particle-interactions-higgs-boson-leptons-quarks-gluons-photon-w-w-z-2/
Prof. David J. Miller, A quasi-political Explanation of the Higgs Boson for Mr. Waldegrave, UK Science Minister 1993. [2]
In 1993, British Science Minister William Waldegrave challenged the physicists: "I have not decided if my department will fund the proposed experiments to search for the Higgs boson, but I promise to fund a bottle of champagne to the person who can explain me what it is." Later on, Prof. David J. Miller came out with a metaphor of describing the activity of Higgs Boson and the Higgs field as Ex-Prime-Minister in a party and won the champagne. I just find it quite amusing and interesting so I decided to include it in.
http://www.hep.ucl.ac.uk/~djm/higgsa.html
http://en.wikinoticia.com/culture-science/Science/47314-the-higgs-boson-for-dummies
Ian Sample (2011), MASSIVE: THE HUNT FOR THE GOD PARTICLE. Croydon: Virgin Books. P203-208.
An interesting book that talked about many information on the Higgs Boson and how people have been chasing for this particle for years. However it doesn’t have the most updated about the recent researches in CERN about the Higgs Boson
Bill Bryson (2009), Notes from a Large Hadron Collider, THE TIMES
This newspaper article has great information on CERN but not really focusing on the physic behind the Higgs.
Higgs Boson production and decay [3]
Provided pictures for further understanding of how the Higgs Boson decays into other elementary particles.
http://www.hep.man.ac.uk/dzero/teaching/gridsite-admin.cgi?cmd=print&file=higgsdecay2.html
Ian Sample and James Randerson, What is the Higgs boson?, the guardian
The same author as the book: MASSIVE: THE HUNT FOR THE GOD PARTICLE. This time it includes more up-to-date information in it.
http://www.guardian.co.uk/science/2011/dec/13/higgs-boson-lhc-explained
Michael D. Lemonick (2012), The Higgs Boson: Have Scientists Found the Mystery Particle? , TIMES Science
Provided a basic idea of what the Higgs Boson and where the research is being done.
http://www.time.com/time/health/article/0,8599,2108525,00.html
The Higgs Boson and the Mystery of Mass, space math, NASA [4]
This is actually a weekly exercise provided by space math which is organized by NASA. It explained why the mass of Higgs is not constant and includes an equation explaining that.
http://spacemath.gsfc.nasa.gov/weekly/6Page86.pdf
(2011), Higgs field gives mass, not the Higgs boson, The Hindu
http://www.thehindu.com/sci-tech/science/article2714897.ece
Video about the Higgs Boson:
This is basically an eight minute video on an interview with a scientist in CERN. The video’s description states: A visit with particle physicist Daniel Whiteson at CERN, where he talks about what the mysterious Higgs Boson is and how the Large Hadron Collider (LHC) will find it (if it exists).
www.youtube.com/watch?v=Iimom5WPrSA