نتایج جستجو برای: 3he
تعداد نتایج: 1796 فیلتر نتایج به سال:
Jefferson Lab experiment E01-012 measured the 3He spin-structure functions and virtual photon asymmetries in the resonance region in the momentum transfer range 1.0<Q2<4.0 (GeV/c)2. Our data, when compared with existing deep inelastic scattering data, were used to test quark-hadron duality in g1 and A1 for 3He and the neutron. In addition, preliminary results on the 3He spin-structure function ...
Polar ice provides an archive for the influx of cosmic dust. Here, we present a high-resolution, glacial-to-interglacial record of cosmic dust using helium isotope analysis of the European Project for Ice Coring in Antarctica (EPICA) ice core drilled in Dronning Maud Land. We obtained a relatively constant 3He flux over the past 30,000 years. This finding excludes 3He as a pacemaker of late Ple...
We show that there are restrictions on the maximum tipping angle that can be used without significantly raising the temperature of the 3He distribution in high B/T spin-echo experiments with pure liquid 3He and 3He-4He solutions. The temperature increase occurs during the diffusion process as quasiparticles in mixed-spin states are scattered and converted into thermal excitations at the spin-up...
G. Lawes,1 S. C. J. Kingsley,1,* N. Mulders,2 and J. M. Parpia1 1Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 2Department of Physics and Astronomy, University of Delaware, Newark, Delaware (Received 15 December 1999) We have investigated the superfluid transition of 3He in different samples of silica aerogel. By comparing new measurements on a 99.5% sample ...
We have discovered new features of the current-phase relation, I f , in superfluid 3He weak links. Firstly, we find that at any given temperature there are two distinct I f functions that characterize the weak link. Secondly, both functions continuously develop an unusual form that ultimately leads to the previously reported p state. The observed form of I f has recently been predicted for unco...
We present experimental results of the first high-precision test of quark-hadron duality in the spin-structure function g_{1} of the neutron and 3He using a polarized 3He target in the four-momentum-transfer-squared range from 0.7 to 4.0 (GeV/c);{2}. Global duality is observed for the spin-structure function g_{1} down to at least Q;{2}=1.8 (GeV/c);{2} in both targets. We have also formed the p...
We propose a theory which exploits the charge-exchange reactions (3He,3Hπ+) and (p,nπ+) as effective sources of virtual pions. We consider processes in which the creation of virtual pions is followed by conventional coupled-channel pion scattering to discrete nuclear states. This picture allows us to incorporate successful theories of pion scattering and utilize virtual pions as probes of the n...
We simultaneously confine fermionic metastable 3He atoms and bosonic metastable 4He atoms in a magneto-optical trap. The trapped clouds, containing up to 1.5 x 10(8) atoms of each isotope, are characterized by measuring ions and metastable helium atoms escaping from the trap. Optical pumping of 3He atoms to a nontrapped hyperfine state is investigated and it is shown that large atom numbers can...
We demonstrate spin-exchange optical pumping of 3He using a "hybrid" K-Rb vapor mixture. The Rb atoms absorb light from a standard laser at 795 nm, then collisionally polarize the potassium atoms. Spin-exchange collisions of K and 3He atoms then transfer the angular momentum to the 3He with much greater efficiency than Rb-3He. For a K-rich vapor, the efficiency of the hybrid spin-exchange colli...
We study a two-phase sample of superfluid 3He where vorticity exists in one phase (3He-A) but cannot penetrate across the interfacial boundary to a second coherent phase (3He-B). We calculate the bending of the vorticity into a surface vortex sheet on the interface and solve the internal structure of this new type of vortex sheet. The compression of the vorticity from three to two dimensions en...
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