Triple metre Triple metre Triple metre (or Am. triple meter, also known as triple time) is a musical metre characterized by a "primary" division of 3 beats to the bar, usually indicated by 3 (simple) or 9 (compound) in the upper figure of the time signature, with , , and being the most common examples. The upper figure being divisible by three does not of itself indicate triple metre; for example, a time signature of usually indicates compound duple metre, and similarly usually indicates compound quadruple metre. Shown below are a simple and a compound triple drum pattern. It is reasonably common
Double beta decay or double beta decay are predicted to be very long; hence, quadruple beta decay is unlikely to be realized. The eight candidate nuclei for quadruple beta decay include Zr, Xe, and Nd capable of quadruple beta-minus decay, and Xe, Ba, Gd, and Dy capable of quadruple beta-plus decay or electron capture. In theory, quadruple beta decay may be experimentally observable in three of these nuclei, with the most promising candidate being Nd. Double beta decay In nuclear physics, double beta decay is a type of radioactive decay in which two neutrons are simultaneously transformed into two protons, or vice versa,