Quark (dairy product) these products are obtained by straining yogurt (milk fermented with thermophile bacteria), quark is made from soured milk fermented with mesophile bacteria. Quark is possibly described by Tacitus in his book "Germania" as "lac concretum" ("thick milk"), eaten by Germanic peoples. However, this could also have meant soured milk or any other kind of fresh cheese or fermented milk product. Although quark is sometimes referred to loosely as a type of "cottage cheese", they can be distinguished from the different production aspects and textural quality, with the cottage cheese grains described as more chewy or meaty. The word "Quark" (Late
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