How do the other particles in nature acquire mass?

Research in elementary particle physics is concentrated on the search for a particle called the Higgs Boson. This particle is the missing piece of our present understanding of nature, known as the Standard Model.
 

For over 50 years scientists from across the world have been trying to create an ideal standard mass by producing a solid that consists of a known quantity of identical atoms, and weigh it.

Thanks to the efforts of Russian scientists, such a material is available. It is superpure silicon – pure in the sense that the vast majority of its composition is made up of silicon-28 atoms. As far as other impurities are concerned, including other silicon isotopes, they may be found in proportions not exceeding one atom for every 10 million silicon-28 atoms.

It is superpure silicon, 99.99% comprised of the silicon-28 isotope. There will be 5 kg of such silicon in three years time. This will be sufficient to produce a kilogram sphere, the number of silicon-28 atoms in which will be known precisely. At last the outdated weight held at the Bureau of Weights and Measures in Paris will be replaced by a standard in which not only the mass, but also the number of atoms will be defined to the maximum achievable limit of accuracy for world science today. For the first time scientists the world over will be able to clarify one of the most fundamental chemical values – the Avogadro Constant.