![]() So the answer is, both of these diagrams have to be included in calculating the crossection, so sometimes it is a W- one way and/or a W+ the other, due to the uncertainty principle in time ordering. In electron capture, an electron from an inner orbital is captured by the nucleus of the atom, and combined with a proton to form a neutron. We used an in situ portable flume, which consists in a transparent. This is why some books show W+ going one way and others show a W- going the other. High energy scaling formulas for K-electron capture by low-charge projectiles are given. The existence of one diagram implies the other. Electron capture ( K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. Each of these modes of decay leads to the formation of a new nucleus with a more stable n:p ratio. Nuclear reactions also often involve rays, and some nuclei decay by electron capture. ![]() The uncertainty principle means that you don't know exactly when the particles react. The most common types of radioactivity are decay, decay, emission, positron emission, and electron capture. When one writes the quark diagrams for electron capture, the reverse can also happen, within the Uncertainty principle of quantum mechanics, depending on the time evolution, there are two diagrams:īoth of these reactions occur superposed. Looking at the quark content, proton uud and neutron udd, an up quark (charge +2/3) has to turn into a down quark (charge -1/3), which happens with the an up -> d +W*+, the star because the W is in a virtual state, off mass shell. The resulting emission is called freefree radiation because the electron is free both before and after the interaction it is not captured by the ion. We are in the quantum mechanical regime,for a proton to turn into a neutron a quark interaction has to happen, again from conservation of charge. BUT the Feynman diagram rules can read it as W- from right to left. ![]() Usually one plots the arrow from left to right. In electron capture, ignoring the quark level, this is the diagram:Ĭonservation of charge needs a positron, which means the intermediate virtual boson exchanged going from left to right has to carry a + charge.
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