Quark (dairy product) 6.1). Acidification allowed to continues until the pH reaches around 4.6, at which acidity level the casein proteins in the milk begins to precipitate. In Germany, the curd is continuously stirred to prevent it from getting hard, resulting in a thick, creamy texture. According to German regulations on cheese ("Käseverordnung"), "fresh cheeses" ("Frischkäse") such as quark or cottage cheese must contain at least 73% water in the fat-free component. German quark is usually sold in plastic tubs with most or all of the whey. This type of quark has the firmness of sour cream but is slightly drier, resulting in
Top quark of a weak isospin doublet. The top quark was sometimes called "truth quark" in the past, but over time "top quark" became the predominant use. The proposal of Kobayashi and Maskawa heavily relied on the GIM mechanism put forward by Sheldon Lee Glashow, John Iliopoulos and Luciano Maiani, which predicted the existence of the then still unobserved charm quark. When in November 1974 teams at Brookhaven National Laboratory (BNL) and the Stanford Linear Accelerator Center (SLAC) simultaneously announced the discovery of the J/ψ meson, it was soon after identified as a bound state of the missing charm quark with its