The 800-ton cosmic-ray spectrograph (MUTRON) has been used to measure the sea-level energy spectrum of cosmic-ray muons arriving from 86" to 90" zenith angles in the momentum region of 100-20000 GeV/c. The measured muon energy spectrum can be interpreted by using a cosmic-ray primary spectrum of (1.80 ~m -~s -' s r -' G e~-' )~-~~~~d~ (E in GeV) and a scaling model incorporating an increasing interaction cross section for meson production in hadron-hadron interaction. The muon charge ratio at energies up to 15 TeV in the same zenith-angle range has been measured. It shows a small enhancement with increasing energy. By combining both results we may conclude that the cosmic-ray primary particle composition stays the same up to about 100 TeV as that obtained by direct measurements in the energy range below 1 TeV.

We find that thermal-energy muonium atoms are emitted from a clean hot tungsten foil in which positive muons are stopping near the surface. The temperature dependence of the thermalmuonium signal yields a surprisingly low activation energy of 0.66(4) eV, suggesting that we are observing the thermionic emission of muonium from the solid. The total muonium yield at 2300 K is about 0.04 per stopped muon of 23 MeV/c initial muon momentum. A number of new experiments should be possible using this unique source of thermal muonium in vacuum.

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Electron- or X-ray-induced characteristic X-ray analysis has been widely used to determine chemical compositions of materials in vast research fields. In recent years, analysis of characteristic X-rays from muonic atoms, in which a muon is captured, has attracted attention because both a muon beam and a muon-induced characteristic X-ray have high transmission abilities. Here we report the first non-destructive elemental analysis of a carbonaceous chondrite using one of the world-leading intense direct current muon beam source (MuSIC; MUon Science Innovative Channel). We successfully detected characteristic muonic X-rays of Mg, Si, Fe, O, S and C from Jbilet Winselwan CM chondrite, of which carbon content is about 2 wt%, and the obtained elemental abundance pattern was consistent with that of CM chondrites. Because of its high sensitivity to carbon, non-destructive elemental analysis with a muon beam can be a novel powerful tool to characterize future retuned samples from carbonaceous asteroids.

0 (Jtl)--+ 21 87 at North Dakota State University on June 18, 2015 http://ptps.oxfordjournals.org/ Downloaded fromPhysics at a ¢-Factory the transition rate difference between K 0 ---t JCl and JCl ---t K 0 . It is an empirical and explicit demonstration of the failure of time-reversal invariance for the K 0 -JCl system, so called "Kabir's direct test forT-violation" . 2 ), 3 ) To the extent that CPT is a valid symmetry, T violation is equivalent to C P violation and, thus, is expected to occur at a well-defined level.CPT invariance lies at the core of Quantum Field Theory ( QFT), the basic framework of physics, and tests of its validity are of fundamental significance. To date, it has been experimentally examined by a variety of methods; no evidence for CPT violation has been seen and upper bounds for violation parameters have been established. A ¢-factory would provide a unique opportunity to test further for CPT in variance at its variety of aspects. At the Planck mass energy scale, at North Dakota State University on June 18, 2015 http://ptps.oxfordjournals.org/ Downloaded from 4>--+ 'Y'fJ (Br = 1.3%) and 4>--+ 7r+7r-1r 0 , p7r (Br = 14.8%) will provide copious samples of clean rJ's and 1r 0 's, making it possible to study their decay properties with higher sensitivities and lower background levels than has been achieved at fixedtarget experiments. In addition to studies of space-time symmetries, a ¢-factory would provide rich opportunities for tests of chiral Lagrangian predictions, precise measurements of the isospin amplitude structure and tests of the D..I = 1/2 rule in kaon decays to 27r and 37r final states, searches for low mass Higgs or Axions, accurate measurements of kaon form factors, a precision measurement of the (controversial) branching ratio for 1r 0 --+ e+edecay, and tests offl.avor-SU(3) symmetry including, for example, the first observation of the as yet unseen decay 4> --+ 'f/ 1 /, as noted shortly in § 3. Moreover, the intense low momentum neutral kaons may prove to be a useful tool for studying nuclear physics reactions involving the strange quark. The coherence of the pairs of neutral kaons produced from the decays of at North Dakota State University on June 18, 2015 http://ptps.oxfordjournals.org/ Downloaded from Physics at a ¢-Factory 7 the ¢ meson provides an interesting opportunity to examine the validity of Quantum Mechanics by testing Bell's Inequality Theorem in a system that violates C P invariance. 7 )