Muon negative

QUANTUM CALCULATION OF COOPERATIVE MUON-NUCLEAR PROCESSES DISCHARGE OF METASTABLE NUCLEI DURING NEGATIVE MUON CAPTURE... 

The positive muon was discovered in cloud chamber photographs made by C D. Anderson and S.H. Neddermyer on Pike s Peak in 1935, and the negative muon almost simultaneously in cloud chamber photographs made by J.C. Street and E.C. Stevenson. These particles have long been called mu-mesons, but since they are fermions (spin h while all other mesons arc bosons, the name muon is preferred, as is their classification with the leptons because of their small rest mass, which is about 206 mr, where me is the mass of the electron. Another reason is their inability to interact with other particles through the nuclear forces. 

Bilokon H, Castagnoli GC, Castellina S, Piazzoli BD, Mannocchi G, Meroni E, Picchi P, Vernetto S (1989) Flux of vertical negative muons stopping at depths 0.35-1000 hg/cm2. J Geophys Res 94 12,145-12,152... 

A negative muon can participate in a variety of atomic and molecular processes. A muonic atom is formed when a muon stops in matter replacing an electron. A muonic atom interacting with ordinary atoms or molecules can form a muonic molecule. The latter in turn can result in fusion reactions between the nuclei if the target consists of hydrogen isotopes, a phenomenon known as muon catalyzed fusion (pCF) [6]. 

Beams of slow negative muons have been developed and are for example employed in the muonic hydrogen Lamb shift experiment at PSI. Other developments are under way at the Rutherford Appleton Laboratory (RAL) in Chilton,... 

The principle of the experiment is to see an increase in the intensity due to laser-stimulated transitions when negative muons are stopped in the helium gas present in a multipass optical cavity, where a high-density electromagnetic radiation of the correct wavelength is stored it is crucial here that the lifetimes of the levels in which one is interested are around 10 12 s (we recall that the negative muon cascade time is about 1 ns or less). 

It can easily be shown that if is the number of negative muons present in a D level of a helium muonic ion (ii"4 He)p and E/V is the energy density of the radiation at the site of the stopping muon, then the fraction of transitions is given by (v = u/2it is the radiation frequency) ... 

The stability of three-body Coulomb systems is an old problem which has been treated in many particular cases [143-145] and several authors reviewed this problem [146,147]. For example, the He atom (ae e ) and H2 (ppa ) are stable systems, H (pe e ) has only one bound state [108], and the positronium negative ion Ps (e+e e ) has a bound state [148], while the positron-hydrogen system (e pe+) is unbound and the proton-electron-negative-muon pe i ) is an unstable system [149]. In this section, we show that all three-body ABA Coulomb systems undergo a first-order quantum phase transition from the stable phase of ABA to the unstable breakup phase of AB + A as their masses and charges varies. Using the FSS method, we calculate the transition line that... 

Target element Spallation Thermal neutron capture Negative muon capture... 

Figure 1. Depth profiles of °Be, and produetion in quartz by spallation reaetions, eapture of stopped negative muons, and fast muon interaetions, respeetively. The data are based on both experimental determinations and model eal-eulations (Heisinger and Nolle...

Although muons are thought to have the same properties as electrons, as is indeed the case for negative muons, p , which behave as heavy electrons , the chemical properties of positive muons should rather be regarded as light protons . The pt tive muon can pick up an electron from a substance and form a neutral partick called muonium (p e , chemical symbol Mu). TTie atomic paran ters of Mu are very clore to those of H atom excqtt that the mass is 9 times smaller aiKi it is not stable because of the intrinsic decay nature of p. Mu can be regarded as a radioactive isotope of H atom (Table 2). 

The H2 ground electronic state has = 2.00 bohrs = 2.00h /mge. The negative muon (symbol /u, ) is a short-lived (half-life 2 X 10 s) elementary particle whose charge is the same as that of an electron but whose mass is 207 times m. When a beam of negative muons (produced when ions accelerated to high speed collide with ordinary matter) enters H2 gas, a series of processes leads to the formation of muomol-ecular ions that consist of two protons and one muon. This species, symbolized by (p ip)", is an H2 ion in which the electron has been replaced by a muon. Its Rg is ZOok w e = 2.00h /2Qnm,y = (2.00/207) bohr = 0.0051 A. The two nuclei in this... 

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