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 only known way the top quark can decay is through the weak interaction producing a W-boson and a down-type quark (down, strange, or bottom). In particular, it is possible to directly determine the branching ratio Γ(Wb) / Γ(W"q" ("q" = b,s,d)). The best current determination of this ratio is . Since this ratio is equal to according to the Standard Model, this gives another way of determining the CKM element , or in combination with the determination of from single top production provides tests for the assumption that the CKM matrix is unitary. The Standard Model also allows more exotic