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
Bottom quark quarks. Although it almost-exclusively transitions from or to a top quark, the bottom quark can decay into either an up quark or charm quark via the weak interaction. CKM matrix elements "V" and "V" specify the rates, where both these decays are suppressed, making lifetimes of most bottom particles (~10 s) somewhat higher than those of charmed particles (~10 s), but lower than those of strange particles (from ~10 to ~10 s). The combination of high mass and low transition-rate gives experimental collision byproducts containing a bottom quark a distinctive signature that makes them relatively easy to identify using a