Radiative corrections to radiativeπe2decay

Abstract

The lowest order radiative corrections to the width and spectra of the radiative e2 decay are calculated. We take into account the virtual photon emission contribution as well as soft and hard real photon emission contributions. The result turns out to be consistent with the standard Drell-Yan picture for the width and spectra in the leading logarithmical approximation which permits us to generalize it to all orders of perturbation theory. Explicit expressions of nonleading contributions are obtained. The contribution of the short distance is found to be in agreement with standard model predictions. It is presented as a general normalization factor. We check the validity of the Kinoshita-Lee-Nauenberg theorem about the cancellation in the total width of the mass singularities at the zero limit of the electron mass. We discuss the results of the previous papers devoted to this problem. The Dalitz plot distribution is illustrated numerically.A rather detailed calculation of the lowest order RC was carried out in Ref. ͓4͔. Nonclear manipulations with a soft

Break-up channels in muon capture on3He

“…In the same table we collect also the experimental results from Refs. [17][18][19][20] and find a fair agreement with most of them.…”

“…[9] we analyzed also most recent data on more differential capture rates published in Ref. [20]. The data in Ref.…”

“…The data in Ref. [20] were evaluated by means of two methods (denoted by "md I" and "md II" in Table 1). In Fig.…”

Measurement of helium-3 and deuterium stopping power ratio for negative muons

“…A schematic view of the experimantal setup is shown in Fig. 1 (see [22,25] and the next section for details). Varying the gas density in the pure helium target we changed the position of the maximum in the muon stopping distribution along the target length.…”

“…Formulae (2) can also be used for negative muons captured in the H/He mixture (with a proper S-value) due to similarity of µ − and π − masses (207m e and 273m e , respectively). Recently a series of experiments on the study of µ-atomic and µ-molecular processes in a D/ 3 He mixture has been carried out at the Paul Scherrer Institute meson factory [22,23,24]. In the experiments we measured the following characteristics: the nuclear fusion rate in a charge-asymmetrical muon complex (dµ 3 He); the probability for transition of the dµ atom from the excited to the ground state (q 1s ); intensities of x-ray radiation of µHe atoms resulting both from muon capture by 3 He atoms and from transfer of the muon from the dµ atom under its de-excitation to the 3 He nucleus.…”