The behavior of the polarization of negative muons in Zn0.99Co0.01O was studied in order to search for a possible magnetic ordered phase. The sample was obtained using solid phase synthesis from ZnO and Co3O4. Measurements were performed in a magnetic field of 1.5 kG transverse to the muon spin in a temperature range of 5–300 K and in the absence of an external magnetic field at 6 K. No evidence of long-range magnetic order were observed.

The experimental test of possible expansion for the Higgs sector is proposed. The lepton family violation will be studied. To reach this goal we are going to carry out the search for the scalar Goldstone boson in the neutrinoless muon decay mu+ to e+ and alpha. The asymmetry of the muon decay near the high energy edge of Michel spectrum is to be measured. To examine previous TRIUMF data the experiment FAMILON is prepared at the surface muon beam of JINR (Dubna) accelerator. The setup consist of the precision magnetic spectrometer and the device for muSR - analysis.

The effect of uniaxial compression on the behavior of shallow aluminum acceptor centers in silicon has been studied. The μAl impurity atoms were created by implanting negative muons into silicon single crystals doped with phosphorus to 1.6×1013 cm−3 (sample 1) and 1.9×1013 cm−3 (sample 2). The muon polarization was studied in the temperature range 10–300 K. Measurements were performed in a magnetic field of 2.5 kG oriented perpendicularly to the muon spin. The samples were oriented so that the selected crystal axis ([111] and [100] in samples 1 and 2, respectively), the magnetic field, and the initial muon-spin polarization were mutually perpendicular. External pressure applied to the sample along the indicated crystal axis changed both the absolute value of the acceptor magnetic-moment relaxation rate and the character of its temperature dependence.

A study is made into the temperature dependence of residual polarization of negative muons in crystalline silicon with the concentration of impurity of the n-and p-types ranging from 8.7×1013 to 4.1× 1018 cm−3. The measurements are performed in a magnetic field of 1000 G transverse to the muon spin, in the temperature range from 4.2 to 300 K. The form of the temperature dependence of the relaxation rate v of the magnetic moment of the μAl0 acceptor in silicon is determined. For a nondegenerate semiconductor, the relaxation rate depends on temperature as v ∝ Tq (q ≈ 3). A variation in the behavior of the temperature dependence and a multiple increase in the relaxation rate are observed in the range of impurity concentration in excess of 1018 cm−3. The importance of phonon scattering and spin-exchange scattering of free charge carriers by an acceptor from the standpoint of relaxation of the acceptor magnetic moment is discussed. The constant of hyperfine interaction in an acceptor center formed by an atom of aluminum in silicon is estimated for the first time: |Ahf (Al)/2π| ∼ 2.5×106s−1.

Results of studying the temperature dependence of the residual polarization of negative muons in crystalline silicon with germanium (9×10 19 cm −3 ) and boron (4.1×10 18 , 1.34×10 19 , and 4.9×10 19 cm −3 ) impurities are presented. It is found that, similarly to n -and p -type silicon samples with impurity concentrations up to ∼10 17 cm −3 , the relaxation rate ν of the magnetic moment of a μ Al acceptor in silicon with a high impurity concentration of germanium (9×10 19 cm −3 ) depends on temperature as ν∼ T q , q ≈3 at T =(5–30) K. An increase in the absolute value of the relaxation rate and a weakening of its temperature dependence are observed in samples of degenerate silicon in the given temperature range. Based on the experimental data obtained, the conclusion is made that the spin-exchange scattering of free charge carriers makes a significant contribution to the magnetic moment relaxation of a shallow acceptor center in degenerate silicon at T ≲30 K. Estimates are obtained for the effective cross section of the spin-exchange scattering of holes (σ h ) and electrons (σ e ) from an Al acceptor center in Si: σ h ∼10 −13 cm 2 and σ e ∼8×10 −15 cm 2 at the acceptor (donor) impurity concentration n a ( n d )∼4×10 18 cm −3 .

The lifetime of negative muons in the 129Xe 1s state was measured. The muon capture rate in 129Xe is compared with that in the 132, 136Xe isotopes. The capture rate was found to depend on the mass number of the cited isotopes. The experimental results are compared with the results of calculations by the semiempirical Goulard-Primakoff formula.

Temperature-dependent remanent polarization of negative muons in a silicon crystal doped with phosphorus (3.2 × 10 12 , 2.3 × 10 15 , and 4.5 × 10 18 cm −3 ) and aluminum (2 × 10 14 and 2.4 × 10 18 cm −3 ) was examined. Measurements were made over the temperature range 4–300 K in a magnetic field of 2000 G perpendicular to the muon spin. Temperature dependence of the relaxation rate was determined for the magnetic moment of a shallow Al acceptor center in a nondeformed silicon sample, and the hyperfine interaction constant was estimated for the interaction between the magnetic moments of muon and electron shell of the muonic mAl atom in silicon.

The lifetimes of a negative muon in the isotopes 132 Xe and 40 Ar in the solid phase are measured. The lifetime of μ − in the 1 s state of the isotope 132 Xe is τ ( 132 Xe)=101.7±1.7 ns, which corresponds to a total nuclear capture rate Λ c ( 132 Xe)=9.4±0.2 μ s −1 . The lifetime of μ − in the isotope 40 Ar, viz., τ ( 40 Ar)=568±6 ns, corresponding to a capture rate Λ c ( 40 Ar)=1.31±0.01 μ s −1 , is obtained to several times better accuracy as compared to previously published results.

The residual polarization of negative muons in n-type silicon with impurity density (1.6±0.2) · 1013 cm−3 is investigated as a function of temperature in the range 10–300 K. The measurements are performed in an external magnetic field of 0.08 T oriented transversely to the spin of the muons. Relaxation of the muon spin and a shift of the precession frequency are observed at temperatures below 30 K. The relaxation rate at 30 K equals 0.25±0.08 μs−1. The shift of the precession frequency at 20 K equals 7 · 10−3. Both the relaxation rate and the shift of the precession frequency increase as the temperature decreases. At temperatures below 30 K the relaxation rate is described well by the relation Λ=bT−q, where q=2.8±0.2.

The residual polarization of negative muons in p-type Si has been studied as a function of the temperature over the range 4.2-270 K. The measurements were carried out in an external magnetic field of 0.08 T, transverse with respect to the initial polarization direction of the muon beam. The impurity concentration in the sample was 2.10(13) cm-3. A relaxation of the muon spin is observed at temperatures below 30 K. The relaxation rate at T = 30 K is 0. 18 +/- 0.08 mus-1. It increases with decreasing temperature, reaching a value greater than 30 mus-1 at 4.2 K. The initial residual polarization P(t = 0) is constant over the entire temperature range. [P(t = 0) was not determined at 4.2 K because of the high relaxation rate.] At T < 30 K the data on the relaxation rate can be described well by a function LAMBDA = BT(-q), where q = 2.75. A power-law dependence of LAMBDA with a power close to 3 may be evidence that a phonon mechanism plays an important role in the relaxation of the electron moment of the acceptor center.