T. Niinikoski

Search for Sub-eV Mass Solar Axions by the CERN Axion Solar Telescope with 3He Buffer Gas

S. Aune, K. Barth, A. Belov, S. Borghi, ∗ H. Bräuninger, G. Cantatore, J. M. Carmona, S. A. Cetin, J. I. Collar, T. Dafni, M. Davenport, C. Eleftheriadis, N. Elias, C. Ezer, G. Fanourakis, E. Ferrer-Ribas, P. Friedrich, J. Galán, J. A. Garćıa, A. Gardikiotis, E. N. Gazis, T. Geralis, I. Giomataris, S. Gninenko, H. Gómez, E. Gruber, T. Guthörl, R. Hartmann, † F. Haug, M. D. Hasinoff, D. H. H. Hoffmann, F. J. Iguaz, ‡ I. G. Irastorza, J. Jacoby, K. Jakovčić, M. Karuza, K. Königsmann, R. Kotthaus, M. Krčmar, M. Kuster, 16, § B. Lakić, ¶ J. M. Laurent, A. Liolios, A. Ljubičić, V. Lozza, G. Lutz, † G. Luzón, J. Morales, ∗∗ T. Niinikoski, †† A. Nordt, 16, ‡‡ T. Papaevangelou, M. J. Pivovaroff, G. Raffelt, T. Rashba, H. Riege, A. Rodŕıguez, M. Rosu, J. Ruz, 2 I. Savvidis, P. S. Silva, S. K. Solanki, L. Stewart, A. Tomás, M. Tsagri, ‡‡ K. van Bibber, §§ T. Vafeiadis, 9, 12 J. Villar, J. K. Vogel, 20, ¶¶ S. C. Yildiz, and K. Zioutas 12

Dynamic polarization of protons, deuterons, and carbon-13 nuclei thermal contact between nuclear spins and an electron spin--spin interaction reservoir

Hydrogen, deuterium, and carbon-13 nuclear spin systems have been studied in partially deuterated 1,2-ethanediol (CD2OH)2, doped with paramagnetic Crv complexes, between 0.1 and 0.5 K, using the technique of dynamic polarization. Various steady-state and transient measurements demonstrate the existence of a thermal contact between the different spin species of this sample and the electron spin-spin interaction reservoir. The lowest spin temperature attained was about 1.2 mK in a magnetic field of 25 kG, which corresponds to a proton polarization of 97%, to a deuteron polarization of 40%, and to a carbon-13 polarization of 48%.

Search for solar axions by the CERN axion solar telescope with 3He buffer gas: closing the hot dark matter gap.

Introduction.—The most promising method to searchfor axions and axion-likeparticles (ALPs) [1–4], low-massbosons with a two-photon interaction vertex, is their con-version to photons in macroscopic magnetic fields [5–7].This approach includes the search for solar axions by thehelioscope technique [8–15], photon regeneration exper-iments (“shining light through a wall”) [16–18], axion-photon conversion in astrophysical B fields [19–22], andthe search for galactic axion dark matter [23–27].One limiting factor in any of these efforts is the mo-mentum difference between freely propagating photonsand axions caused by the axion mass m

Dynamic proton polarization in propanediol below 0.5 K

Abstract Dynamic proton polarizations of +98 −4 +2 % and −100 −0 +4 % have been obtained in 1,2-propanediol doped with Cr v -complexes, at a sample temperature of about 0.37 K in a 2.5 T magnetic field. Short polarization time constants indicate that the mechanism for obtaining these high polarizations is the cooling of the electron spin-spin interaction reservoir. The temperature and field dependence of the proton spin-lattice relaxation time were measured down to 55 mK and 0.2 T.

The polarized target station at GKSS

Abstract In cooperation with CERN, a dynamic polarized nuclear target station was built at GKSS-Research Center on SANS-1, aimed at investigation of biomolecule structure. The target consists of a 20 mmol/min dilution refrigerator, which has a basic temperature of 50 mK, a 2.5 T electromagnet, and a carcinotron which delivers the 4 mm microwave at a power up to 5 W. A NMR-system based on the Liverpool Q -meter and the CERN 68K-STAC fulfills the task of polarization measurement, and especially selective nuclear depolarization.

Measurement of the analysing power and the differential cross section of the pp charge-exchange reaction at LEAR

Abstract As part of a programme to study the spin structure of the p p→ n n channel, we have measured the analysing power A 0 n and the differential cross section at an incident antiproton beam momentum of 704 MeV/ c . The analysing power exhibits a remarkable angular dependence, which is poorly reproduced by the existing potential models.

Asymmetry in p¯p elastic scattering

Abstract Asymmetries A 0 n have been measured at LEAR for s ¯ s elastic scattering for 15 beam momenta from 497 to 1550 MeV/ c .

Forward produced hadrons in μp and μd scattering and investigation of the charge structure of the nucleon

Final data measured with the EMC forward spectrometer are presented on the production of forward charged hadrons in μp and μd scattering at incident beam energies between 100 and 280 GeV. The large statistic of 373 000 events allows a study of the semi-inclusive hadron production as a function ofz,pT2 and 〈pT2〉 in smallQ2,xBj andW bins. Charge multiplicity ratios and differences as a function ofz andxBj are given forp, d andn-targets. From the differences of charge multiplicities the ratio of the valence quark distributions of the protondv(x)/uv(x) is determined for the first time in charged lepton scattering. The Gronau et al. sum rule is tested, the measured sum being 0.31±0.06 stat. ±0.05 syst., compared with the theoretical expectation of 2/7≈0.286. The measured sum corresponds to an absolute value of the ratio of thed andu quark charge of 0.44±0.10 stat.±0.08 syst.

Experimental support for the Kondo theory for light particle tunneling in metals

Abstract The nature of the diffusion process for positive muons in aluminium below 2 K has been clarified by an experiment in the superconducting state. In the sample studied, Al Li (75 ppm), the diffusion rate of the muon towards the lithium impurity atoms was found to be considerably higher in the superconducting state than in the normal state. This is direct evidence for the predicted influence of conduction electrons on the quantum diffusion of positively charge light particles in metals.

Muon diffusion in copper bolow 2K

Transverse field μSR experiments were performed on several different samples of copper in the temperature range below 2K, including isotope separated copper, Fe and Si doped polycrystalline copper and monocrystalline copper. No strong isotope dependent effect was observed. A63Cu and a natural copper sample of identical purity both yield 0.16 μs−1 for the low-temperature plateau, while an increased linewidth inthe65Cu case may be related to the strong effects of Fe impurities. Careful transverse field measurements on large single crystals at 0.08K reveal non-Gaussian lineshapes in accordance with the picture of diffusing muons at this temperature. This allows us to reject several of the existing models for muon behaviour in copper below 2K.