Quark (dairy product) as the Vermont Creamery in Vermont, and some specialty retailers carry it. Lifeway Foods manufactures a product under the title "farmer cheese" which is available in a variety of metropolitan locations with former Russian populations. Elli Quark, a Californian manufacturer of quark, offers soft quark in different flavors. In Canada, the firmer East European variety of quark is manufactured by Liberté Natural Foods; a softer German-style quark is manufactured in the Didsbury, Alberta, plant of Calgary-based Foothills Creamery. Glengarry Fine Cheesemaking in Lancaster (Eastern Ontario) also produces Quark. Also available in Canada is the very similar "Dry Curd Cottage Cheese"
Quark state to a lower mass state. Because of this, up and down quarks are generally stable and the most common in the universe, whereas strange, charm, bottom, and top quarks can only be produced in high energy collisions (such as those involving cosmic rays and in particle accelerators). For every quark flavor there is a corresponding type of antiparticle, known as an antiquark, that differs from the quark only in that some of its properties (such as the electric charge) have equal magnitude but opposite sign. The quark model was independently proposed by physicists Murray Gell-Mann and George Zweig in