Quark (dairy product) a somewhat crumbly texture (like ricotta). The basic quark this basic quark or skimmed quark ("Magerquark") must under German Law have less than 10% fat by dry mass. Quark with higher fat content is made by adding cream after cooling. It has a very smooth and creamy texture and is slightly sweet (unlike sour cream). A firmer version called "Schichtkäse" (layer cheese) is often used for baking. Schichtkäse is distinguished from quark by having an added layer of cream sandwiched between two layers of quark. Quark is also often sold flavored with herbs, spices, or fruit. In general, dry mass
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