Higgs Boson
There’s a field called Higgs field everywhere in the universe. This field is very important; it gives
mass to the matter. The Higgs field consists of Higgs bosons. When any type of particle goes
through the Higgs field, it interacts with it, and gets its mass. This can be compared to walking in
water or snow, the H O-molecules slow you down just like the Higgs bosons do to the particles.
Some particles interact more with the Higgs field than the others, those particles are more
massive. For example, top quarks interact a lot with the field and go through it slowly. The theory
of the Higgs boson was first developed by Peter Higgs, Robert Brout, Francois Englert, Gerald
Guralnik, C. R. Hagen and Tom Kibble.
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The scientist need a very big accelerator to be able to observe the Higgs boson, because a huge
amount of energy is needed when trying to produce the Higgs bosons by smashing particles. LHCaccelerator in Switzerland is big enough to do that; on 4th July 2012 CERN announced that they
had found a new particle that could be the Higgs boson. The features of the particle were similar
to the predicted features of Higgs boson, for example zero spin, and the examinations have been
repeated since with alike results, so the scientist believe the Higgs boson has finally been found.
Still, more studies need to be done to confirm that this particle really is the Higgs boson.
History of the Higgs Boson and Peter Higgs
Peter Ware Higgs is a British theoretical physicist, emeritus professor at the University of
Edinburgh and a Nobel Prize laureate for his life-long work on the mass of subatomic particles.
He was born 29th of May 1929 in Newcastle upon Tyne, England. He was raised in Bristol and
mostly homeschooled in his childhood. He went to Cotham Grammar School from 1941 to 1946
and was inspired by the work of Paul Dirac, a founder of the field of quantum mechanics, who was
an alumni of that school.
In the age of 17 he moved to City of London School, where he specialized in mathematics, and
continued to King's College London in 1947, where he received a bachelor’s degree (1950),
master’s degree (1951), and doctorate (1954) in physics. His PhD was for a thesis entitled 'Some
problems in the theory of molecular vibrations', which started his life-long interest in the
application of symmetry to physical systems.
He became a Senior Research Fellow at the University of Edinburgh during his time there, from
1954-1956. There he first became interested in mass and developed the idea that particles,
massless in the beginning of the universe, acquired mass a split second later due to interaction
with a theoretical field (which later became known as the Higgs field). He has said that there was
no eureka moment in developing his theorem, which he did on a camping trip to the Highlands. At
this time he was also lecturing at Imperial College and University College in London. The basis of
Higgs' theorem came from the Japanese theorist and Nobel Prize laureate Yoichiro Nambu, who
had proposed a theory known as spontaneous symmetry breaking, which Higgs started correcting
and extending.
Other physicists, Robert Brout, Francois Englert, Gerald Guralnik, C. R. Hagen and Tom Kibble had
reached similar conclusions to Higgs' theorem in their studies about the same time. The Belgian
Francois Englert shared the Nobel Prize with Higgs in 2013.
In addition to the Nobel Prize, Peter Higgs has won many notable awards throughout his career.
For example, Wolf Prize in Physics (shared with Englert and Brout) in 2004, Sakurai Prize in 2010,
Dirac Medal in 1997, Rutherford Medal and Prize in 1984, FRS (Fellow of the Royal Society) in
1983, Hughes Medal in 1981 and Copley Medal in 2015 (The oldest still existing scientific prize in
the world). He has received honorary degrees from 14 different universities, mostly in the UK. He
has also turned down a knighthood in 1999, but accepted a membership of The Order of the
Companion of Honour. He has expressed cynisism towards the honours system and said it is only
used for political purposes. A centre of theoretical physics of the University of Edinburgh has also
been named after him in 2012.
Beyond Higgs Boson, some theoretical and unknown particles
In Standard Model the Higgs boson is the last missing particle to complete the model, while some
other theories predict that there are more than just one Higgs boson.
Gravitons
Graviton is a hypothetical particle that carries the force of gravitation in a same way as the
photons carry the electromagnetic force and the W and Z bosons carry the weak interaction. The
graviton is excepted to be massless because the gravitational force has infinite range and the
graviton doesn’t have an electric charge. The graviton would be a boson with the spin value of 2.
Wimps
The WIMPs (weakly interactive massive particles) are a hypothetical particle candidate for dark
matter. Wimps only interract with gravitational force and weak interaction which makes observing
them very hard as gravitation and weak interaction are the least powerful forces.
Tetraquarks
A tetraquark is a particle (meson) that is composed ot four quarks. Some tetraquarks have been
produced in particle colliders, such as Fermilab.
5-quarks
A pentaquark is a particle that consists of four quarks and one antiquark. Pentaquarks can have
varying shapes, some are shaped like a sphere and some are shaped like a molecule consisting of a
trio of three quarks and a quark-antiquark pair. Some pentaquarks have been produced artificially.
Superpartners
Superpartners, also called spartners are hypothetical elementary (=can’t be broken into smaller
parts) particles. According to supersymmetry theory, each boson has a partner fermion, which is
called the boson’s superpartner and similarly each fermion has a boson superpartner. The particle
and its superpartner would have exact same mass. No evidence of superpartners have been found
in collider experiments, but it’s possible that the creation of superpartners would need higher
energy collisions that are possible to create with LHC.
particle
superpartner of the particle
neutral bosons neutralino
charged bosons chargino
photon
photino
higgs boson
higgsino
gluon
neutrino
graviton
gluino
sneutrino
gravitino
Axions
Axions are hypothetical elementary particles that solve the strong CP problem (very complex to
explain). If they exist, they could be a component of hypothetical cold dark matter (dark matter
that has not been moved much by random motions in the early universe). No evidence of axions
have been found in collider experiments.
Chameleons
Chameleons are hypothetical scalar (=spin equals 0) particle that is affected by gravity but isn’t
affected much by matter. The mass of a chameleon would scale with local energy density (heavier
in higher density).
Glueball
Glueball is a hypothetical composite particle that consists solely of gluon (gluons are the exchange
particles for the strong force between quarks that holds them together) particles. Glueball are
extremely difficult to find in particle accelerators because they mix with some ordinary particles
and their existance is predicted by the Standard Model (= the current theory for the quantum
physics). Glueballs have not yet been officially identified but some experimental particles have
been found that have similar properties with a Standard Model glueball.
Significance - Scientific impact and the future of the Higgs boson
Evidence of the Higgs field and its properties has been extremely significant scientifically for many
reasons. Here are some examples:
Validating the Standard Model, or choosing between extensions and alternatives
Does the Higgs field exist, which fundamentally validates the Standard Model through the
mechanism of Mass generation? If it does, then which more advanced extensions are suggested or
excluded based upon measurements of its properties? What else can we learn about this
fundamental field, now that we have the experimental means to study its behavior and
interactions? Alternatively, if the Higgs field doesn't exist, which alternatives and modifications to
the Standard Model are likely to be preferred? Will the data suggest an extension, or a completely
different approach (such as supersymmetry or string theory)?
Related to this, a belief generally exists among physicists that there is likely to be "new" physics
beyond the Standard Model—the Standard Model will at some point be extended or superseded.
The Higgs field and related issues present a promising "doorway" to understand better the places
where the Standard Model might become inadequate or fail, and could provide considerable
evidence guiding researchers into future enhancements or successors.
Finding how certain particles acquire mass
Electroweak symmetry breaking (due to a Higgs field or otherwise) is believed proven responsible
for the masses of fundamental particles such as elementary fermions (including electrons and
quarks) and the massive W and Z gauge bosons. Finding how this happens is pivotal to particle
physics.
It is worth noting that the Higgs field does not 'create' mass out of nothing (which would violate
the law of conservation of energy). Nor is the Higgs field responsible for the mass of all particles.
For example, about 99% of the mass of baryons (composite particles such as the proton and
neutron) is due instead to the kinetic energy of quarks and to the energies of (massless) gluons of
the strong interaction inside the baryons. In Higgs-based theories, the property of 'mass' is a
manifestation of potential energy transferred to particles when they interact ("couple") with the
Higgs field, which had contained that mass in the form of energy.
Insight into cosmic inflation
There has been considerable scientific research on possible links between the Higgs field and the
inflaton – a hypothetical field suggested as the explanation for the expansion of space during the
first fraction of a second of the universe (known as the "inflationary epoch"). Some theories
suggest that a fundamental scalar field might be responsible for this phenomenon; the Higgs field
is such a field and therefore has led to papers analysing whether it could also be the inflaton
responsible for this exponential expansion of the universe during the Big Bang. Such theories are
highly tentative and face significant problems related to unitarity, but may be viable if combined
with additional features such as large non-minimal coupling, a Brans–Dicke scalar, or other "new"
physics, and have received treatments suggesting that Higgs inflation models are still of interest
theoretically.
Insight into the nature of the universe, and its possible fates
Finding how symmetry breaking happens within the electroweak interaction
Below an extremely high temperature, electroweak symmetry breaking causes the electroweak
interaction to manifest in part as the short-ranged weak force, which is carried by massive gauge
bosons. Without this, the universe we see around us could not exist, because atoms and other
structures could not form, and reactions in stars such as our Sun would not occur. But it is not
clear how this actually happens in nature. Is the Standard Model correct in its approach, and can it
be made more exact with actual experimental measurements? If not the Higgs field, then what is
breaking symmetry in its place?
Sources:
http://www.pbs.org/wgbh/nova/blogs/physics/2014/05/what-are-gravitons/
http://io9.gizmodo.com/what-are-gravitons-and-why-cant-we-see-them-1643904640
https://en.wikipedia.org/wiki/Higgs_boson
http://home.cern/topics/higgs-boson
http://www.extremetech.com/extreme/208652-what-is-the-higgs-boson