Influence of epithermal muonic molecule formation on kinetics of the μ\muCF processes in deuterium

The non-resonant formation of $dd\mu$ molecules in the loosely bound state in collisions of non-thermalized $d\mu$ atoms with deuterium molecules D$_2$ has been considered. The process of such a type is possible only for collision energies exceeded the ionization potential of D$_2$. The calculated rates of $dd\mu$ formation in the above-threshold energy region are about one order of magnitude higher than obtained earlier. The role of epithermal non-resonant $\mu$-molecule formation for the kinetics of $\mu$CF processes in D$_2$ gas was studied. It was shown that the non-resonant $dd\mu$ formation by $d\mu$ atoms accelerated during the cascade can be directly observed in the neutron time spectra at very short initial times.Comment: 6 pages, 5 figures, Proceedings of the International Conference on Exotic Atoms and Related Topics EXA-2011, Vienna, Sep 5-9, 201

Precise measurement of muon capture on the proton

The aim of the muCap experiment is a 1% measurement of the singlet capture rate Lambda(S) for the basic electro-weak reaction mu + p --> n + nu(mu). This observable is sensitive to the weak form-factors of the nucleon, in particular to the induced pseudoscalar coupling constant g(p). It will provide a rigorous test of theoretical predictions based on the Standard Model and effective theories of QCD. The present method is based on high precision lifetime measurements of mu(-) in hydrogen gas and the comparison with the free mu(+) lifetime. The mu(-) experiment will be performed in ultra-clean, deuterium-depleted H-2 gas at 10 bar. Low density compared to liquid H-2 is chosen to avoid uncertainties due to ppmu formation. A time projection chamber acts as a pure hydrogen active target. It defines the muon stop position in 3D and detects rare background reactions. Decay electrons are tracked in cylindrical wire-chambers and a scintillator array covering 75% of 4pi