Elementary Particles Presented

humanino

ok with me
but Marlon started this

and I would like to add something to your last post Marlon. I already wanted to to add it in the other thread : there are other possibilities to generate mass dynamically, among which one I want to mention because of its role in QCD : instantons are also able to break chiral symmetry and give non-vanishing value to the quark condensate. In fact, instanton-based calculations are much in agreement with actual value of the quark condensate (this quark condensate is the order parameter in the phase transition where the breaking of chiral symmetry occurs). Unfortunately, I do not have much time right now to write an account on this.

Also in your post, should not QHC be replaced with QHD (quantum hadro-dynamics) ?

marlon

Indeed this is very correct... I am planning to write down a text on instantons. Basically they are the QFT-variant of what we call tunneling in QM. The QM-tunneling lowers the vaccuum-energy-value and in QFT it is the instantons that are able to tunnel from one vacuum-gauge-configuration to another...

See this nice link for an indept explanation by Gerardus t'Hooft :
http://xxx.lanl.gov/abs/hep-th/0010225

Indeed, thanks for the correction...

regards
marlon

marlon

Magnetic monopoles are looked at as being point particles in QFT. Like i stated before, for example in the dual abelian Higgsmodell, they are used in order to describe the dual analogon of the Meissner-effect that pushes the magnetic field lines out of a superconductive specimen...The actual charge of such a monopole is determined in those points of the space-time where the gauge of the field theory is undetermined. This means, where this gauge becomes singular...


I attached a zip-document in which quantization of magnetic charge is explained. The reason for this phenomenon is the Dirac-quantization which makes sure that the Dirac string is not noticable when you pass through a surface that is subtended by a deformed world-line

regards
marlon

marlon

http://www.arxiv.org/abs/hep-ph/0111062
http://www.arxiv.org/abs/hep-ph/9906526
http://www.arxiv.org/abs/hep-ph/9910526

These are a few links on magnetic monopoles...Beware : A solid QFT-knowledge is required...these papers are far from introductory...

regards
marlon

davidmerritt

Excellent I'll post them sometime soon..... just thought I'd add one or two of my links on the topic of the standard model and EPP

UK particle physics and astronomy research council
http://www.pparc.ac.uk

University College London's course on Particle and Nuclear physics
http://www.hep.ucl.ac.uk/~jthomas/notes3c24.html

Queen Mary (westfield) London EPP course
http://hepwww.ph.qmw.ac.uk/epp/lectures.shtml

Sheffield University Particle Physics courses
http://www.shef.ac.uk/physics/resear...a/teaching.htm

Durham university's Institute for Particle Physics Phenomenology (what a name!)
http://www.ippp.dur.ac.uk


My rubish notes on the Higgs Boson

There is something missing from modern particle physics, that something is the proof of the existence of the Higgs Boson (which only has mass , no charge or spin). In order for Gauge invariance to hold there needs to be a mechanism by which gauge bosons can acquire mass. The process which provides mass endowment is called the ‘Higgs Mechanism’.

The standard model (explained above) predicts the existence of the Higgs particle; however, it does not predict an accurate mass. The research effort is lead by the European CERN project, a collection of large colliders, the focus of which was the LEP. Unfortunately the LEP (Large Electron Positron) collider has been dismantled in favour of the construction of the LHC (large hadron collider) due to be in service in 2007. A suspect result at CERN caused them to announce that they’d found the Higgs particle, but they’d miscalculated. The research group at FNAL near Chicago are hoping to identify the elusive particle, however there is a growing number of concerned particle physicists speculating that the standard model is flawed. As the power of the colliders increases over 140GeV scientists become increasingly sceptical of existence of the Higgs boson. Explaining how particles gain mass will remain a mystery for the time being!

and some links:
• http://news.bbc.co.uk/1/hi/sci/tech/3546973.stm
• http://www.newscientist.com/news/news.jsp?id=ns99991649
• http://www.cerncourier.com/main/article/39/9/12

marlon

This years Physics Nobel Prize was awarded for the discovery of
asymptotic freedom of the strong force. This means that the strong
force gets weaker in strength when energy gets higher. For example
consider two quarks that interact with each other via the strong force.
When they have a very high kinetic energy they will be less tightly
bound because of this high energy (strong interaction is weaker). This
also results in the fact that no single quark can be found in the
vaccuumstate (lowest energy or groundstate). This phenomenon is called
quark confinement. Quarks will always sit per two (meson) or per three
(baryon, like the proton or neutron).

Quarks were discovered (well, i mean they were "observed"
experimentally) by performing deep inelastic scattering experiments
with electrons onto protons. By studying the electromagnetic
interactions, scientist found out that some fraction of the proton
(Feynmann called these fractions partons)was "knocked out" by the
high-energy-incident electron. Thus suggesting that protons were
constituted out of something more fundamental. Another suggestion for
this was the fact that the neutron did exhibit a nuclear magnetic
moment that was NOT equal to (so not neutral)...

Theoretically quarks were implemented via group theory in the famous
Eightfold-way...Thus QCD was born, the field theory that describes the
quark-interactions at best via 8 gauge bosons called gluons. Each quark
has a flavour bottom-, ...quarks) and each such flavour also has
a colour-quantum-number (Red,Green,Blue)...These quantumnumbers
"decide" via conservation laws how quarks interact with each other...

regards
marlon

marlon

If anyone is interested in a simple explanation of asymptotic freedom and the concept of screening versus anti-screening...well, check out my journal...just look for "ON THE ORIGIN OF "CONFINED" SPECIES"

regards
marlon

i also included the link to the Nobel lectures on this years physics Nobel Prize, as a reference...great stuff...again thanks to marcus for providing us with such great links..i suggest you all check it out...

marlon

I have written an introductory text on the meaning and role of the Higgs field in QFT. If you are interested, please check out my journal and read the "what is the higgs field"-entry


regards
marlon

ps : any comments are always welcome...both good as well as bad...

selfAdjoint

Marlon, could you clarify the transition from your example of electron spins to the mass-acquiring Higgs field? Surely you don't mean that the spin lineup of the elecrons is due to a Higgs mechanism? But your text reads that way.

marlon

Thanks for the remark sA..

Ofcourse as you know the transition is certainly not triggered by the Higgs field. It originates when the temperature of the specimen goes under a certain transition value. I mean, when the nearest neigbor interaction between two spins (the one tells the other to postion itself into the same direction : this is the definition of ferromagnetism) becomes dominant over the "chaos among the spins" caused by higher temperatue values of the specimen. In easier language : when the temperature is low enough there won't be enough kinetic energy of the particles at hand, to disturb the natural tendency of spin-ordening that is caracteristic for ferromagnetism...


regards
marlon

marlon

http://www.physicsforums.com/journal...page=10&page=2


In my journal i wrote a text as an attempt to explain the Higgs-particle and how it can be accounted for the mass-generation of elementary particles. Also (see the above link) i wrote a reference to a site. This site gives the results of the 1993 HIGGS-CONTEST...Wanna know what this is, check out my journal...


marlon

Astronuc

Another simple overview of elementary particles - Fundamental Particles and Interactions

Look for the Chart of Fundamental Particles and Interactions

marlon

http://www.physicsforums.com/journal...0dark%20matter

Go check out the new text on Preons. This is hot new stuff but still very speculative. I also included a reference to a peer reviewed text given to me here on this forum. If anyone has other links on preons, just let me know.


Preons are assumed to be more fundamental the quarks (STILL SPECULATIVE AND NOT PROVEN!!!!!!!!) and they are a good candidate for dark matter...
regards
marlon

pelastration

Can I find somewhere on Internet a full overview or tree scheme about all particles and all their possible decays?

Thanks.

Dirk

marlon

Hallo Dirk,

This is an overview from CERN

http://pdg.web.cern.ch/pdg/particlea...ess/chart.html

Marlon aka Nikolaas

pelastration

Thanks Marlon,
You provided already in previous posts good links.

yes I know the CERN chart, it's very interesting. But what I am looking for is a more in depth overview. A tree scheme - the kind as you see in the image on http://abyss.uoregon.edu/~js/glossary/quarks.html. For example the CERN chart says there are 120 Baryons and 140 type of mesons. Any idea where we can find those?

regards
dirk

marlon

http://home.cwru.edu/~sjr16/advanced...ticlephys.html

this site gives a few more

marlon