".........Mass is now a routine research topic in particle physics." That is the line in an article.  As a non-physicist, I didn't know that until I have read and blogged about "black holes and LHC".  There are still so many things which have attracted my attention. So, I have done some research on this word "mass".  Now, I've started to understand it a bit and I want to share it with you.

Masses arise from interactions of fundamental particles with the Higgs field.

Here are ten basic features of Higgs field. You might be interested in it.

1. The Higgs field is a kind of quantum fields. A good example of a quantum field is the electromagnetic field (such as radio waves, cellphone signals, etc) of which its elementary particle is the photon.
2. The Higgs boson (or Higgs particle) is the particle of the Higgs field and has spin 0. (Electrons have spin ½ and photons have spin 1.)
3. The masses of Higgs bosons are presently not known accurately. (The past experiments gave some tantalizing data about them.)
   
4. The Higgs field is present throughout the universe. (and may have different fields.)
   
5. The Higgs field has nonzero strength throughout the universe, while the electromagnetic field has zero strength on cosmic scales.
6. Shape of the Higgs field, unlike ordinary fields which have zero fields at the valley floor, is like a valley with a hillock at its center (at zero field) and the lowest point of the valley forms a circle around the hillock (see picture below).  The universe, like a ball, comes to rest somewhere on this circular trench, which corresponds to a nonzero value of the field. That is, in its natural, lowest energy state, the universe is permeated throughout by a /nonzero/ Higgs field.
7. Particles that interact with the Higgs field behave as if they have mass, proportional to the strength of the field times the strength of the interaction.
8. The proton mass would be about what it is even without the Higgs field.
9. The masses of the quarks themselves, however, and also the mass of the electron, are entirely caused by the Higgs field. Those masses would vanish without the Higgs.
10. Three almost identical families of particles are (1) up, down, electron neutrino, electron; (2) charm, strange, muon neutrino, muon; (3) and top, bottom, tau neutrino, tau. These families have different masses.  Therefore, the interactions with the Higgs field must differ among these families of particles.

Notes:

1. Higgs fields are also called Higgs molasses.
2. Spin property is  an intrinsic quantity of angular momentum of particles.
3. Supersymmetric Standard Models (SSMs) are the extensions of the Standard Model. In these models, each Standard Model particle has a so-called superpartner (as yet undetected) with closely related properties. At least two different Higgs fields are needed in SSMs.
4. For every known species of particle (electrons, quarks, neutrinos, etc.), supersymmetry implies the existence of a partner species (called, selectrons, squarks, sneutrinos, etc.) that to date has never been observed.
5. If sparticles are discovered, our understanding of dark matter will be advanced. Dark matter is abundant in space but does not give off light and hence is known only through its gravitational influence. Dark matter is thought to be composed of sparticles.
6. Direct tests of the idea that mass arises from the interactions with the different Higgs fields can be done with three key features.
   • Look for the signature particles called Higgs bosons. These quanta must exist, or else the explanation is not right.
   • Once they are detected we can observe how Higgs bosons interact with other particles.
   • Different sets of Higgs fields, as occur in the Standard Model or in the various SSMs, imply different sets of Higgs bosons with various properties, so tests can distinguish these alternatives, too.

Higgs Field

References

1. Gordon Kane. The Mysteries of Mass. Scientific American Magazine. June 27, 2005.
2. Brian Greene (a professor of mathematics and physics at Columbia) New York Times.  From http://www.nytimes.com/2008/09/12/opinion/12greene.html?_r=2&oref=slogin&pagewanted=all&oref=slogin (accessed 13 Sep 08)

Appendix:
Professor P. Higgs, at Edinburgh University, explained The Higgs Mechanism.