Spin dependence in superelastic electron scattering from Na(3P)
International Nuclear Information System (INIS)
McClelland, J.J.; Kelley, M.H.; Celotta, R.J.
1985-01-01
Measurements are presented of spin asymmetries for superelastic scattering of 10-eV spin polarized electrons from the excited Na(3P/sub 3/2/) state created by linearly polarized laser optical pumping. Asymmetries as large as 16% are observed in scattering from a state which is not spin-polarized. Results are shown both as a function of scattering angle with fixed laser polarization direction, and as a function of the laser polarization direction at a fixed scattering angle
A collection of formulas for spin dependent deep inelastic scattering
International Nuclear Information System (INIS)
Pussieux, T.
1995-03-01
The analysis of the longitudinal spin structure functions of the proton, neutron and deuteron requires the use of a large number of formulas and numerical inputs taken from various unpolarized experiments. The aim of this report is to collect this information which is usually scattered in the literature. (author). 26 refs., 3 figs., 1 tab
Medium energy inelastic proton-nucleus scattering with spin dependent NN interaction
International Nuclear Information System (INIS)
Ahmad, I.; Auger, J.P.
1981-12-01
The previously proposed effective profile expansion method for the Glauber multiple scattering model calculation has been extended to the case of proton-nucleus inelastic scattering with spin dependent NN interaction. Using the method which turns out to be computationally simple and of relatively wider applicability, a study of sensitivity of proton-nucleus inelastic scattering calculation to the sometimes neglected momentum transfer dependence of the NN scattering amplitude has been made. We find that the calculated polarization is particularly sensitive in this respect. (author)
Higher order spin-dependent terms in D0-brane scattering from the matrix model
International Nuclear Information System (INIS)
McArthur, I.N.
1998-01-01
The potential describing long-range interactions between D0-branes contains spin-dependent terms. In the matrix model, these should be reproduced by the one-loop effective action computed in the presence of a non-trivial fermionic background ψ. The v 3 ψ 2 /r 8 term in the effective action has been computed by Kraus and shown to correspond to a spin-orbit interaction between D0-branes, and the ψ 8 /r 11 term in the static potential has been obtained by Barrio et al. In this paper, the v 2 ψ 4 /r 9 term is computing in the matrix model and compared with the corresponding results of Morales et al. obtained using string theoretic methods. The technique employed is adapted to the underlying supersymmetry of the matrix model, and should be useful in the calculation of spin-dependent effects in more general Dp-brane scatterings. (orig.)
On the mechanism of spin-dependent (e,2e) scattering from a ferromagnetic surface
International Nuclear Information System (INIS)
Samarin, S N; Sergeant, A D; Pravica, L; Cvejanovic, D; Wilkie, P; Guagliardo, P; Williams, J F; Artamonov, O M; Suvorova, A A
2009-01-01
A simple model is suggested for a qualitative analysis of spin-dependent (e,2e) reaction on a ferromagnetic surface. The model is based on the scattering of the primary electron with the average spin projection 1 > by the valence electron with the average spin projection 2 >. To test the model the energy distributions of correlated electron pairs are measured for parallel and anti-parallel orientations of the magnetic moment of the cobalt film and polarization vector of the incident beam. The proposed model explains qualitatively the spin-asymmetry of the measured binding energy spectrum.
Nikolaev, M. A.; Klapdor-Kleingrothaus, H. V.
1993-06-01
We present calculations of the nuclear from factors for spin-dependent elastic scattering of dark matter WIMPs from123Te and131Xe isotopes, proposed to be used for dark matter detection. A method based on the theory of finite Fermi systems was used to describe the reduction of the single-particle spin-dependent matrix elements in the nuclear medium. Nucleon single-particle states were calculated in a realistic shell model potential; pairing effects were treated within the BCS model. The coupling of the lowest single-particle levels in123Te to collective 2+ excitations of the core was taken into account phenomenologically. The calculated nuclear form factors are considerably less then the single-particle ones for low momentum transfer. At high momentum transfer some dynamical amplification takes place due to the pion exchange term in the effective nuclear interaction. But as the momentum transfer increases, the difference disappears, the momentum transfer increases and the quenching effect disappears. The shape of the nuclear form factor for the131Xe isotope differs from the one obtained using an oscillator basis.
International Nuclear Information System (INIS)
Nikolaev, M.A.; Klapdor-Kleingrothaus, H.V.
1993-01-01
We present calculations of the nuclear from factors for spin-dependent elastic scattering of dark matter WIMPs from 123 Te and 131 Xe isotopes, proposed to be used for dark matter detection. A method based on the theory of finite Fermi systems was used to describe the reduction of the single-particle spin-dependent matrix elements in the nuclear medium. Nucelon single-particle states were calculated in a realistic shell model potential; pairing effects were treated within the BCS model. The coupling of the lowest single-particle levels in 123 Te to collective 2 + excitations of the core was taken into account phenomenologically. The calculated nuclear form factors are considerably less then the single-particle ones for low momentum transfer. At high momentum transfer some dynamical amplification takes place due to the pion exchange term in the effective nuclear interaction. But as the momentum transfer increases, the difference disappears, the momentum transfer increases and quenching effect disappears. The shape of the nuclear form factor for the 131 Xe isotope differs from the one obtained using an oscillator basis. (orig.)
Scattering of polarized 7Li by 120Sn and projectile-target spin-dependent interactions
International Nuclear Information System (INIS)
Sakuragi, Y.; Yahiro, M.; Kamimura, M.; Tanifuji, M.
1986-07-01
Scattering of 7 Li by 120 Sn targets at E lab = 44 MeV is investigated in the coupled-channel frame by taking account of the projectile virtual excitations to the lowest three excited states. Calculations are performed by the cluster-folding (CF) interactions and the double-folding (DF) one. Both interactions reproduce very well the expeimental data on the cross section, the vector analyzing power, the second-rank tensor ones and the third-rank tensor one in elastic and projectile inelastic scattering, although some differences are found between the CF results and the DF ones. In the calculation, the virtual excitations of the projectile are important for most of the analyzing powers and the spin-orbit interaction is indispensable for the vector analyzing power. These features are in contrast to those in 7 Li - 58 Ni scattering at 20 MeV and are interpreted as over-Coulomb-barrier effects. The scattering amplitudes and the analyzing powers are investigated by the invariant amplitude method, which provides a key connecting the spin-dependent interactions to the analyzing powers. The method proposes an important relationship between the tensor analyzing powers, which is useful in analyses of both theoretical and experimental results. Finally, it is found that in the elastic scattering the second-rank tensor analyzing powers are proportional to the strength of the second-rank tensor interaction and the vector and third-rank tensor analyzing powers to the square or cube of the strength of this interaction, while in the inelastic scattering the cross section is proportional to the square of the strength of the tensor interaction, other quantities being weakly dependent on the strength. (author)
Spin-dependent scattering by a potential barrier on a nanotube
International Nuclear Information System (INIS)
Abranyos, Yonatan; Gumbs, Godfrey; Fekete, Paula
2010-01-01
The electron spin effects on the surface of a nanotube have been considered through the spin-orbit interaction (SOI), arising from the electron confinement on the surface of the nanotube. This is of the same nature as the Rashba-Bychkov SOI at a semiconductor heterojunction. We estimate the effect of disorder within a potential barrier on the transmission probability. Using a continuum model, we obtain analytic expressions for the spin-split energy bands for electrons on the surface of nanotubes in the presence of SOI. First we calculate analytically the amplitudes of scattering from a potential barrier located around the axis of the nanotube into spin-dependent states. The effect of disorder on the scattering process is included phenomenologically and induces a reduction in the transition probability. We analyze the relative role of SOI and disorder in the transmission probability which depends on the angular and linear momentum of the incoming particle, and its spin orientation. Finally we demonstrate that in the presence of disorder, perfect transmission may not be achieved for finite barrier heights.
Effect of Δ-isobar excitation on spin-dependent observables of elastic nucleon-deuteron scattering
International Nuclear Information System (INIS)
Nemoto, S.; Oryu, S.; Chmielewski, K.; Sauer, P.U.
2000-01-01
Δ-isobar excitation in the nuclear medium yields an effective three-nucleon force. A coupled-channel formulation with Δ-isobar excitation developed previously is used. The three-particle scattering equations are solved by a separable expansion of the two-baryon transition matrix for elastic nucleon-deuteron scattering. The effect of Δ-isobar excitation on the spin-dependent observables is studied at energies above 50 MeV nucleon lab energy. (author)
Klos, P.; Menéndez, J.; Gazit, D.; Schwenk, A.
2013-01-01
We perform state-of-the-art large-scale shell-model calculations of the structure factors for elastic spin-dependent WIMP scattering off 129,131Xe, 127I, 73Ge, 19F, 23Na, 27Al, and 29Si. This comprehensive survey covers the non-zero-spin nuclei relevant to direct dark matter detection. We include a pedagogical presentation of the formalism necessary to describe elastic and inelastic WIMP-nucleus scattering. The valence spaces and nuclear interactions employed have been previously used in nucl...
Pion nucleus scattering lengths
International Nuclear Information System (INIS)
Huang, W.T.; Levinson, C.A.; Banerjee, M.K.
1971-09-01
Soft pion theory and the Fubini-Furlan mass dispersion relations have been used to analyze the pion nucleon scattering lengths and obtain a value for the sigma commutator term. With this value and using the same principles, scattering lengths have been predicted for nuclei with mass number ranging from 6 to 23. Agreement with experiment is very good. For those who believe in the Gell-Mann-Levy sigma model, the evaluation of the commutator yields the value 0.26(m/sub σ//m/sub π/) 2 for the sigma nucleon coupling constant. The large dispersive corrections for the isosymmetric case implies that the basic idea behind many of the soft pion calculations, namely, slow variation of matrix elements from the soft pion limit to the physical pion mass, is not correct. 11 refs., 1 fig., 3 tabs
Energy Technology Data Exchange (ETDEWEB)
Kaptari, Leonya P. [University of Perugia (Italy); INFN-Perugia (Italy); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Joint Inst. for Nuclear Research, Dubna (Russia); Del Dotto, Alessio [University of Rome, Rome (Italy); INFN-Roma (Italy); Pace, Emanuele [University of Rome (Italy); INFN-Tor Vergata (Italy); Salme, Giovanni [INFN-Roma (Italy); Scopetta, Sergio [University of Perugia (Italy); INFN-Perugia (Italy)
2014-03-01
The spin dependent spectral function, relevant to describe polarized electron scattering off polarized {sup 3}He, is studied, within the Plane Wave Impulse Approximation and taking into account final state interaction effects (FSI). In particular, the case of semi-inclusive deep inelastic scattering (SiDIS) is considered, evaluating the FSI of the hadronizing quark with the nuclear remnants. It is shown that particular kinematical regions can be selected to minimize the latter effects, so that parton distributions in the neutron can be accessed. On the other side, in the regions where FSI dominates, the considered reactions can elucidate the mechanism of hadronization of quarks during the propagation in the nuclear medium. It is shown that the obtained spin dependent spectral function can be directly applied to investigate the SiDIS reaction e-vector + {sup 3}He-vector to h+X, where the hadron h originates from the current fragmentation. Experiments of this type are being performed at JLab to extract neutron transverse momentum dependent parton distributions. As a case study, a different SiDIS process, with detection of slow (A-1) systems in the final state, is considered in more details, in order to establish when nuclear structure effects and FSI can be distinguished from elementary reactions on quasi-free nucleons. It is argued that, by a proper choice of kinematics, the origin of nuclear effects in polarized DIS phenomena and the details of the interaction between the hadronizing quark and the nuclear medium can be investigated at a level which is not reachable in inclusive deep inelastic scattering.
Spin dependence in high $p^{2}_{T}$ elastic pp and np scattering
Crabb, D G; Hansen, P.H.; Hauser, J.; Krisch, A.D.; Sandler, B.; Shima, T.; Terwilliger, K.M.; Crosbie, E.A.; Ratner, L.G.; Schultz, P.F.; Thomas, G.H.; O'Fallon, J.R.; Lin, A.D.; Salthouse, A.J.; Linn, S.L.; Perlmutter, A.; Karmakar, N.L.; Kyberd, P.
1979-01-01
Using the polarized proton capability of the Argonne ZGS the authors recently made 90 degrees /sub cm/ measurements of elastic pp scattering from 6 to 11.75 GeV/c, determining the parallel and anti- parallel pure initial spin state cross sections and the associated spin-spin parameter A/sub nn/ with the spins normal to the scattering plane. They find that the parallel to anti-parallel cross section ratio rises dramatically from 1.2+or-.06 at p/sub t//sup 2/=3.3 (GeV /c)/sup 2/ to 3.2+or-.4 at 4.8 (GeV/c)/sup 2/, similar to the p/sub T //sup 2/ dependence previously observed at the fixed laboratory momentum of 11.75 GeV/c. They have also extended the measurements at 6 GeV/c and find that A/sub nn/ has a small but sharp rise at 90 degrees /sub cm/. In addition a month of 12 GeV/c polarized deuteron acceleration in the ZGS enabled them to measure two A/sub nn/ at two points at 6 GeV/c for np elastic scattering: A/sub nn/=-.17+or-.04 at p/sub T//sup 2/=.8, A/sub nn/=-.19+or-.05 at P/sub T//sup 2/=1.0. These value...
Dynamically induced spin-dependent interaction in the elastic scattering of heavy-ions
International Nuclear Information System (INIS)
Imanishi, B.; Oertzen, W. von.
1982-02-01
Dynamical polarization effect in heavy-ion elastic scattering is investigated in the framework of the coupled-reaction-channel theory. By using the adiabatic approximation at low incident energies, this effect is expressed as a spin-orbit (L vector.S vector) interaction with a L vector and S vector independent radial function. The strength of the (L vector.S vector) interaction calculated for the 12 C + 13 C system is in the same order of magnitude as deduced from experiments and is about two orders of magnitude larger than that obtained from the folding model calculation. (author)
Adams, D; Adeva, B; Akdogan, T; Arik, E; Arvidson, A; Badelek, B; Ballintijn, M K; Bardin, Dimitri Yuri; Bardin, G; Baum, G; Berglund, P; Betev, L; Bird, I G; Birsa, R; Björkholm, P; Bonner, B E; De Botton, N R; Boutemeur, M; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Cavata, C; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Dyring, A; Eichblatt, S; Faivre, Jean-Claude; Fasching, D; Feinstein, F; Fernández, C; Frois, Bernard; Gallas, A; Garzón, J A; Gaussiran, T; Giorgi, M A; von Goeler, E; Gómez, F; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Kalinovskaya, L V; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kishi, A; Kiselev, Yu F; Klostermann, L; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Lindqvist, T; Litmaath, M; Loewe, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Van Middelkoop, G; Miller, D; Mori, K; Moromisato, J H; Nagaitsev, A P; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Parks, D P; Perrot-Kunne, F; Peshekhonov, V D; Piegaia, R; Pinsky, L; Platchkov, S K; Pló, M; Polec, J; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Pussieux, T; Pyrlik, J; Rädel, G; Rijllart, A; Roberts, J B; Rock, S E; Rodríguez, M; Rondio, Ewa; Rosado, A; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schüler, K P; Seitz, R; Semertzidis, Y K; Sever, F; Shanahan, P; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Steigler, U; Stuhrmann, H B; Szleper, M; Teichert, K M; Tessarotto, F; Tlaczala, W; Trentalange, S; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Weinstein, R; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Yañez, A; Ylöstalo, J; Zanetti, A M; Zaremba, K; Zhao, J
1997-01-01
We present a new measurement of the spin-dependent structure function $g_{1}^{\\rm d}$ of the deuteron from deep inelastic scattering of 190 GeV polarized muons on polarized deuterons. The results are combined with our previous measurements of $g_{1}^{\\rm d}$. A perturbative QCD evolution in next-to-leading order is used to compute $g_{1}^{\\rm d}(x)$ at a constant $Q^{2}$. At $Q^{2} = 10$ GeV$^{2}$, we obtain a first moment $\\Gamma_{1}^{\\rm d} = \\int_{0}^{1} g_{1}^{\\rm d}{\\rm d}x = 0.041 \\pm 0.008$, a flavour-singlet axial charge of the nucleon $a_{0} = 0.30 \\pm 0.08$, and an axial charge of the strange quark $a_{s} = -0.09 \\pm 0.03$. Using our earlier determination of $\\Gamma_{1}^{\\rm p}$, we obtain $\\Gamma_1^{\\rm p} - \\Gamma_1^{\\rm n} = 0.183 \\pm 0.035$ at $Q^2 = 10\\,\\mbox{GeV}^2$. This result is in agreement with the Bjorken sum rule which predicts $\\Gamma_1^{\\rm p} - \\Gamma_1^{\\rm n} = 0.186 \\pm 0.002$ at the same $Q^2$.
Summary of neutron scattering lengths
International Nuclear Information System (INIS)
Koester, L.
1981-12-01
All available neutron-nuclei scattering lengths are collected together with their error bars in a uniform way. Bound scattering lengths are given for the elements, the isotopes, and the various spin-states. They are discussed in the sense of their use as basic parameters for many investigations in the field of nuclear and solid state physics. The data bank is available on magnetic tape, too. Recommended values and a map of these data serve for an uncomplicated use of these quantities. (orig.)
Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bradley, A.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chapman, J. J.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; de Viveiros, L.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Malling, D. C.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Ott, R. A.; Palladino, K. J.; Pangilinan, M.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration
2016-04-01
We present experimental constraints on the spin-dependent WIMP (weakly interacting massive particle)-nucleon elastic cross sections from LUX data acquired in 2013. LUX is a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota), which is designed to observe the recoil signature of galactic WIMPs scattering from xenon nuclei. A profile likelihood ratio analysis of 1.4 ×104 kg day of fiducial exposure allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn=9.4 ×10-41 cm2 (σp=2.9 ×10-39 cm2 ) at 33 GeV /c2 . The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.
International Nuclear Information System (INIS)
Volkov, M.K.; Osipov, A.A.
1983-01-01
The msub(π)asub(0)sup(1/2)=0.1, msub(π)asub(0)sup(3/2)=-0.1, msub(π)asub(0)sup((-))=0.07, msub(π)sup(3)asub(1)sup(1/2)=0.018, msub(π)sup(3)asub(1)aup(3/2)=0.002, msub(π)sup(3)asub(1)sup((-))=0.0044, msub(π)sup(5)asub(2)sup(1/2)=2.4x10sup(-4) and msub(π)sup(5)asub(2)sup(3/2)=-1.2x10sup(-4) scattering lengths are calculated in the framework of the composite meson model which is based on four-quark interaction. The decay form factors of (rho, epsilon, S*) → 2π, (K tilde, K*) → Kπ are used. The q 2 -terms of the quark box diagrams are taken into account. It is shown that the q 2 -terms of the box diagrams give the main contribution to the s-wave scattering lengths. The diagrams with the intermediate vector mesons begin to play the essential role at calculation of the p- and d-wave scattering lengths
Institute of Scientific and Technical Information of China (English)
YANG YongHong; WANG YongGang; LIU Mei; WANG Jin
2002-01-01
Two kinds of spin-depcndcnt scattering effects (magnetic-iinpurity and spin-orbit scatterings) axe investi-gated theoretically in a quasi-two-dimensional (quasi-2D) disordered electron system. By making use of the diagrammatictechniques in perturbation theory, we have calculated the dc conductivity and magnetoresistance due to weak-localizationeffects, the analytical expressions of them are obtained as functions of the interlayer hopping energy and the charac-teristic times: elastic, inelastic, magnetic and spin-orbit scattering times. The relevant dimensional crossover behaviorfrom 3D to 2D with decreasing the interlayer coupling is discussed, and the condition for the crossover is shown to bedependent on the aforementioned scattering times. At low temperature there exists a spin-dcpendent-scattering-induccddimensional crossover in this system.
International Nuclear Information System (INIS)
Bray, Igor.
1992-04-01
The calculations of the 3 2 S and 3 2 P spin asymmetries and the angular momentum for singlet and triplet scattering for projectile energies of 10 and 20 eV is presented. Together these observables give a most stringent test of any electron-atom scattering theory. An excellent agreement was found between the results of the coupled-channel optical method and experiment, which for the spin asymmetries can only be obtained by a good description of the couplings between the lower-lying target states and the target continuum. 10 refs., 2 figs
2002-01-01
The aim of the experiment is to measure @*N spin obssservables using a frozen spin target and a high resolution spectrometer (SPES II). The &bar.NN scattering is usually described with NN potentials transformed by G-parity, where the large annihilation cross section (@s^a^n/@s^e^l$>$2) is taken into account. The different theoretical approaches fit reasonably well the existing data on spin integrated cross sections. For the spin dependent observables, the predictions depend consistently on the theoretical inputs.\\\\ \\\\ A strong energy dependence of the @*p polarization Ay(@q) is predicted. We plan to check it measuring the angular distribution of Ay(@q) for @* momenta between 300 and 700 MV/c. Using a deuterium target, measurements of Ay(@q) for @*d in the same energy range will provide information on @*n scattering.\\\\ \\\\ The @* beam hits a 5 mm thick frozen spin target which has a large opening aperture. We expect a polarization of @=~80\\% with a low holding field of (.35Tm). The incident trajectory is de...
Neutron scattering lengths of 3He
International Nuclear Information System (INIS)
Alfimenkov, V.P.; Akopian, G.G.; Wierzbicki, J.; Govorov, A.M.; Pikelner, L.B.; Sharapov, E.I.
1976-01-01
The total neutron scattering cross-section of 3 He has been measured in the neutron energy range from 20 meV to 2 eV. Together with the known value of coherent scattering amplitude it leads to the two sts of n 3 He scattering lengths
AUTHOR|(CDS)2067425; Arvidson, A; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; De Botton, N R; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Eichblatt, S; Fasching, D; Feinstein, F; Fernández, C; Forthmann, S; Frois, Bernard; Gallas, A; Garzón, J A; Gilly, H; Giorgi, M A; Görtz, S; Gracia, G; De Groot, N; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Karev, A G; Ketel, T; Kiryluk, J; Kiselev, Yu F; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Grosse-Perdekamp, M; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Rädel, G; Rijllart, A; Reicherz, G; Rodríguez, M; Rondio, Ewa; Roscherr, B; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schiller, A; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Windmolders, R; Wislicki, W; Witzmann, A; Ylöstalo, J; Zanetti, A M; Zaremba, K
1997-01-01
We present a new measurement of the virtual photon proton asymmetry $A_1^{\\rm p}$ from deep inelastic scattering of polarized muons on polarized protons in the kinematic range $0.0008 1$ GeV$^{2}$. A perturbative QCD evolution in next-to-leading order is used to determine $g_1^{\\rm p}(x)$ at a constant $Q^2$. At $Q^{2} = 10$ GeV$^{2}$ we find, in the measured range, $\\int_{0.003}^{0.7} g_{1}^{\\rm p}(x){\\rm d}x = 0.139 \\pm 0.006~({\\rm stat})\\pm 0.008~({\\rm syst)} \\pm 0.006~({\\rm evol})$. The value of the first moment $\\Gamma_{1}^{\\rm p} = \\int_{0}^{1} g_{1}^{\\rm p}(x){\\rm d}x$ of $g_{1}^{\\rm p}$ depends on the approach used to describe the behaviour of $g_{1}^{\\rm p}$ at low $x$. We find that the Ellis-Jaffe sum rule is violated. With our published result for $\\Gamma_{1}^{\\rm d}$ we confirm the Bjorken sum rule with an accuracy of $\\approx 15\\%$ at the one standard deviation level.
Shang, Liangliang; He, Yangle; Lian, Jingwei; Pan, Yusi
2018-05-01
The Weakly Interacting Massive Particle (WIMP) has been one of the most attractive candidates for Dark Matter (DM), and the lightest neutralino (\\widetilde{χ }^0_1) in the Next-to-Minimal Supersymmetric Standard Model (NMSSM) is an interesting realization of the WIMP framework. The Galactic Center Excess (GCE) indicated from the analysis of the photon data of the Fermi Large Area Telescope (Fermi-LAT) in the gamma-ray wavelength ≲ 1 fm, can be explained by WIMP DM annihilations in the sky, as shown in many existing works. In this work we consider an interesting scenario in the Z_3-NMSSM where the singlet S and Singlino \\widetilde{S}^0 components play important roles in the Higgs and DM sector. Guided by our analytical arguments, we perform a sophisticated scan over the NMSSM parameter space by considering various observables such as the Standard Model (SM) Higgs data measured by the ATLAS and CMS experiments at the Large Hadron Collider (LHC), and the B-physics observables BR(B_s→ X_sγ ) and BR(B_s→ μ ^+μ ^-). We first collect samples which can explain the GCE well while passing all constraints we consider except for the DM direct detection (DD) bounds from XENON1T and PandaX-II experiments. We analyze the features of these samples suitable for the GCE interpretation and find that \\widetilde{χ }^0_1 DM are mostly Singlino-like and annihilation products are mostly the bottom quark pairs \\bar{b}b through a light singlet-like CP-odd Higgs A_1. Moreover, a good fit to the GCE spectrum generically requires sizable DM annihilation rates 0 in today's Universe. However, the correlation between the coupling C_{A_1 b\\bar{b}} in 0 and the coupling C_{Z \\widetilde{χ }^0_1 \\widetilde{χ }^0_1} in DM-neutron Spin Dependent (SD) scattering rate σ ^{SD}_{\\widetilde{χ }^0_1-N} makes all samples we obtain for GCE explanation get excluded by the PandaX-II results. Although the DM resonant annihilation scenarios may be beyond the reach of our analytical
Resonance effects in neutron scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Lynn, J.E.
1989-06-01
The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-/angstrom/ wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs.
Resonance effects in neutron scattering lengths
International Nuclear Information System (INIS)
Lynn, J.E.
1989-01-01
The nature of neutron scattering lengths is described and the nuclear effects giving rise to their variation is discussed. Some examples of the shortcomings of the available nuclear data base, particularly for heavy nuclei, are given. Methods are presented for improving this data base, in particular for obtaining the energy variation of the complex coherent scattering length from long to sub-angstrom wave lengths from the available sources of slow neutron cross section data. Examples of this information are given for several of the rare earth nuclides. Some examples of the effect of resonances in neutron reflection and diffraction are discussed. This report documents a seminar given at Argonne National Laboratory in March 1989. 18 refs., 18 figs
Variational lower bound on the scattering length
International Nuclear Information System (INIS)
Rosenberg, L.; Spruch, L.
1975-01-01
The scattering length A characterizes the zero-energy scattering of one system by another. It was shown some time ago that a variational upper bound on A could be obtained using methods, of the Rayleigh-Ritz type, which are commonly employed to obtain upper bounds on energy eigenvalues. Here we formulate a method for obtaining a variational lower bound on A. Once again the essential idea is to express the scattering length as a variational estimate plus an error term and then to reduce the problem of bounding the error term to one involving bounds on energy eigenvalues. In particular, the variational lower bound on A is rigorously established provided a certin modified Hamiltonian can be shown to have no discrete states lying below the level of the continuum threshold. It is unfortunately true that necessary conditions for the existence of bound states are not available for multiparticle systems in general. However, in the case of positron-atom scattering the adiabatic approximation can be introduced as an (essentially) solvable comparison problem to rigorously establish the nonexistence of bound states of the modified Hamiltonian. It has recently been shown how the validity of the variational upper bound on A can be maintained when the target ground-state wave function is imprecisely known. Similar methods can be used to maintain the variational lower bound on A. Since the bound is variational, the error in the calculated scattering length will be of second order in the error in the wave function. The use of the adiabatic approximation in the present context places no limitation in principle on the accuracy achievable
Summary of coherent neutron scattering length
International Nuclear Information System (INIS)
Rauch, H.
1981-07-01
Experimental values of neutron-nuclei bound scattering lengths for some 354 isotopes and elements and the various spin-states are compiled in a uniform way together with their error bars as quoted in the original literature. Recommended values are also given. The definitions of the relevant quantities presented in the data tables and the basic principles of measurements are explained in the introductory chapters. The data is also available on a magnetic tape
Spin dependent photon structure functions
International Nuclear Information System (INIS)
Manohar, A.V.; Massachusetts Inst. of Tech., Cambridge
1989-01-01
Spin dependent structure functions of the photon are studied using the operator product expansion. There are new twist-two photon and gluon operators which contribute. The structure functions g 1 and F 3 are calculable in QCD, but differ from their free quark values. The corrections to F 3 are suppressed by 1/log Q 2 . The calculation is an extension of the analysis of Witten for the spin averaged structure functions F 1 and F 2 . (orig.)
On the spin-dependent sensitivity of XENON100
Energy Technology Data Exchange (ETDEWEB)
Garny, Mathias [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan [Technische Univ. Muenchen, Garching (Germany). Physik-Department
2012-11-15
The latest XENON100 data severely constrains dark matter elastic scattering off nuclei, leading to impressive upper limits on the spin-independent cross-section. The main goal of this paper is to stress that the same data set has also an excellent spin-dependent sensitivity, which is of utmost importance in probing dark matter models. We show in particular that the constraints set by XENON100 on the spin-dependent neutron cross-section are by far the best at present, whereas the corresponding spin-dependent proton limits lag behind other direct detection results. The effect of nuclear uncertainties on the structure functions of xenon isotopes is analysed in detail and found to lessen the robustness of the constraints, especially for spin-dependent proton couplings. Notwith-standing, the spin-dependent neutron prospects for XENON1T and DARWIN are very encouraging. We apply our constraints to well-motivated dark matter models and demonstrate that in both mass-degenerate scenarios and the minimal supersymmetric standard model the spin-dependent neutron limits can actually override the spin-independent limits. This opens the possibility of probing additional unexplored regions of the dark matter parameter space with the next generation of ton-scale direct detection experiments.
On the spin-dependent sensitivity of XENON100
International Nuclear Information System (INIS)
Garny, Mathias; Ibarra, Alejandro; Pato, Miguel; Vogl, Stefan
2012-11-01
The latest XENON100 data severely constrains dark matter elastic scattering off nuclei, leading to impressive upper limits on the spin-independent cross-section. The main goal of this paper is to stress that the same data set has also an excellent spin-dependent sensitivity, which is of utmost importance in probing dark matter models. We show in particular that the constraints set by XENON100 on the spin-dependent neutron cross-section are by far the best at present, whereas the corresponding spin-dependent proton limits lag behind other direct detection results. The effect of nuclear uncertainties on the structure functions of xenon isotopes is analysed in detail and found to lessen the robustness of the constraints, especially for spin-dependent proton couplings. Notwith-standing, the spin-dependent neutron prospects for XENON1T and DARWIN are very encouraging. We apply our constraints to well-motivated dark matter models and demonstrate that in both mass-degenerate scenarios and the minimal supersymmetric standard model the spin-dependent neutron limits can actually override the spin-independent limits. This opens the possibility of probing additional unexplored regions of the dark matter parameter space with the next generation of ton-scale direct detection experiments.
Exploiting Universality in Atoms with Large Scattering Lengths
International Nuclear Information System (INIS)
Braaten, Eric
2012-01-01
The focus of this research project was atoms with scattering lengths that are large compared to the range of their interactions and which therefore exhibit universal behavior at sufficiently low energies. Recent dramatic advances in cooling atoms and in manipulating their scattering lengths have made this phenomenon of practical importance for controlling ultracold atoms and molecules. This research project was aimed at developing a systematically improvable method for calculating few-body observables for atoms with large scattering lengths starting from the universal results as a first approximation. Significant progress towards this goal was made during the five years of the project.
Local-field refinement of neutron scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Sears, V F
1985-06-01
We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed.
Local-field refinement of neutron scattering lengths
International Nuclear Information System (INIS)
Sears, V.F.
1985-01-01
We examine the way in which local field effects in the neutron refractive index affect the values of coherent scattering lengths determined by various kinds of neutron optical measurements. We find that under typical experimental conditions these effects are negligible for interferometry measurements but that they are significant for gravity refractometry measurements, producing changes in the effective scattering length of as much as two or three standard deviations in some cases. Refined values of the scattering length are obtained for the thirteen elements for which data are presently available. The special role of local field effects in neutron transmission is also discussed. (orig.)
Isospin breaking in the pion-nucleon scattering lengths
International Nuclear Information System (INIS)
Hoferichter, Martin; Kubis, Bastian; Meissner, Ulf-G.
2009-01-01
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Isospin breaking in the pion-nucleon scattering lengths
Energy Technology Data Exchange (ETDEWEB)
Hoferichter, Martin [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Kubis, Bastian [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany)], E-mail: kubis@itkp.uni-bonn.de; Meissner, Ulf-G. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institut fuer Kernphysik (Theorie), Institute for Advanced Simulation, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2009-07-06
We analyze isospin breaking through quark mass differences and virtual photons in the pion-nucleon scattering lengths in all physical channels in the framework of covariant baryon chiral perturbation theory.
Synthesis of aerogel tiles with high light scattering length
Danilyuk, A F; Okunev, A G; Onuchin, A P; Shaurman, S A
1999-01-01
The possibility of aerogel tiles production for RICH detectors is described. Monolithic blocks of silica aerogel were synthesized by two-step sol-gel processing of tetraethoxysilane Si(OEt) sub 4 followed by high temperature supercritical drying with organic solvent. The important characteristic of aerogel is the light scattering length. In the wide range of refraction indexes the light scattering length exceeds 4 cm at 400 nm.
A phenomenological π-p scattering length from pionic hydrogen
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Wycech, S.
2004-01-01
We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length a h extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order α 2 logα using an extended charge distribution. A hadronic πN scattering length a h π - p =0.0870(5)m π -1 is deduced leading to a πNN coupling constant from the GMO relation g c 2 /(4π)=14.04(17)
A phenomenological $\\pi^{-}p$ scattering length from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2004-01-01
We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length a/sup h/ extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order alpha /sup 2/ log alpha using an extended charge distribution. A hadronic pi N scattering length a/sub pi -p//sup h/ = 0.0870(5)m/sub pi //sup -1/ is deduced leading to a pi NN coupling constant from the GMO relation g/sub c //sup 2//(4 pi ) = 14.04(17). (28 refs).
Scattering cross section of unequal length dipole arrays
Singh, Hema; Jha, Rakesh Mohan
2016-01-01
This book presents a detailed and systematic analytical treatment of scattering by an arbitrary dipole array configuration with unequal-length dipoles, different inter-element spacing and load impedance. It provides a physical interpretation of the scattering phenomena within the phased array system. The antenna radar cross section (RCS) depends on the field scattered by the antenna towards the receiver. It has two components, viz. structural RCS and antenna mode RCS. The latter component dominates the former, especially if the antenna is mounted on a low observable platform. The reduction in the scattering due to the presence of antennas on the surface is one of the concerns towards stealth technology. In order to achieve this objective, a detailed and accurate analysis of antenna mode scattering is required. In practical phased array, one cannot ignore the finite dimensions of antenna elements, coupling effect and the role of feed network while estimating the antenna RCS. This book presents the RCS estimati...
Salajegheh, Maral; Nejad, S. Mohammad Moosavi; Khanpour, Hamzeh; Tehrani, S. Atashbar
2018-05-01
In this paper, we present SMKA18 analysis, which is a first attempt to extract the set of next-to-next-leading-order (NNLO) spin-dependent parton distribution functions (spin-dependent PDFs) and their uncertainties determined through the Laplace transform technique and Jacobi polynomial approach. Using the Laplace transformations, we present an analytical solution for the spin-dependent Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution equations at NNLO approximation. The results are extracted using a wide range of proton g1p(x ,Q2) , neutron g1n(x ,Q2) , and deuteron g1d(x ,Q2) spin-dependent structure functions data set including the most recent high-precision measurements from COMPASS16 experiments at CERN, which are playing an increasingly important role in global spin-dependent fits. The careful estimations of uncertainties have been done using the standard Hessian error propagation. We will compare our results with the available spin-dependent inclusive deep inelastic scattering data set and other results for the spin-dependent PDFs in literature. The results obtained for the spin-dependent PDFs as well as spin-dependent structure functions are clearly explained both in the small and large values of x .
s -wave scattering length of a Gaussian potential
Jeszenszki, Peter; Cherny, Alexander Yu.; Brand, Joachim
2018-04-01
We provide accurate expressions for the s -wave scattering length for a Gaussian potential well in one, two, and three spatial dimensions. The Gaussian potential is widely used as a pseudopotential in the theoretical description of ultracold-atomic gases, where the s -wave scattering length is a physically relevant parameter. We first describe a numerical procedure to compute the value of the s -wave scattering length from the parameters of the Gaussian, but find that its accuracy is limited in the vicinity of singularities that result from the formation of new bound states. We then derive simple analytical expressions that capture the correct asymptotic behavior of the s -wave scattering length near the bound states. Expressions that are increasingly accurate in wide parameter regimes are found by a hierarchy of approximations that capture an increasing number of bound states. The small number of numerical coefficients that enter these expressions is determined from accurate numerical calculations. The approximate formulas combine the advantages of the numerical and approximate expressions, yielding an accurate and simple description from the weakly to the strongly interacting limit.
Neutron scattering lengths of molten metals determined by gravity refractometry
International Nuclear Information System (INIS)
Reiner, G.; Waschkowski, W.; Koester, L.
1990-01-01
Very accurate values of the coherent neutron scattering lengths of the heavy elements Bi and Pb are important quantities for the investigation of the electric interactions of neutrons with atoms. We performed, therefore, a series of experiments to determine accurate scattering lengths by means of neutron gravity refractometry on liquid mirrors of molten metals. The possible perturbations of the necessary reflection measurements have been discussed in details. After taking into account the uncertainties and corrections associated with observable perturbations we obtained the following values for bound atoms: b(Bi)=8.532±0.002 fm, b(Pb)=9.405±0.003 fm, b(Tl)=8.776±0.005 fm, b(Sn)=6.225±0.002 fm and b(Ga)=7.288±0.002 fm. These data are corrected for the local field effect occuring in the reflection on liquids. The recently reported results for the neutron's electric polarizability and the neutron-electron scattering length are supported by the Bi- and Pb-scattering length of this work. (orig.)
Neutron scattering lengths of molten metals determined by gravity refractometry
Energy Technology Data Exchange (ETDEWEB)
Reiner, G; Waschkowski, W; Koester, L [Technische Univ. Muenchen, Garching (Germany, F.R.). Fakultaet fuer Physik
1990-10-01
Very accurate values of the coherent neutron scattering lengths of the heavy elements Bi and Pb are important quantities for the investigation of the electric interactions of neutrons with atoms. We performed, therefore, a series of experiments to determine accurate scattering lengths by means of neutron gravity refractometry on liquid mirrors of molten metals. The possible perturbations of the necessary reflection measurements have been discussed in details. After taking into account the uncertainties and corrections associated with observable perturbations we obtained the following values for bound atoms: b(Bi)=8.532{plus minus}0.002 fm, b(Pb)=9.405{plus minus}0.003 fm, b(Tl)=8.776{plus minus}0.005 fm, b(Sn)=6.225{plus minus}0.002 fm and b(Ga)=7.288{plus minus}0.002 fm. These data are corrected for the local field effect occuring in the reflection on liquids. The recently reported results for the neutron's electric polarizability and the neutron-electron scattering length are supported by the Bi- and Pb-scattering length of this work. (orig.).
Neutron scattering lengths of molten metals determined by gravity refractometry
Energy Technology Data Exchange (ETDEWEB)
Reiner, G.; Waschkowski, W.; Koester, L. (Technische Univ. Muenchen, Garching (Germany, F.R.). Fakultaet fuer Physik)
1990-10-01
Very accurate values of the coherent neutron scattering lengths of the heavy elements Bi and Pb are important quantities for the investigation of the electric interactions of neutrons with atoms. We performed, therefore, a series of experiments to determine accurate scattering lengths by means of neutron gravity refractometry on liquid mirrors of molten metals. The possible perturbations of the necessary reflection measurements have been discussed in details. After taking into account the uncertainties and corrections associated with observable perturbations we obtained the following values for bound atoms: b(Bi)=8.532{plus minus}0.002 fm, b(Pb)=9.405{plus minus}0.003 fm, b(Tl)=8.776{plus minus}0.005 fm, b(Sn)=6.225{plus minus}0.002 fm and b(Ga)=7.288{plus minus}0.002 fm. These data are corrected for the local field effect occuring in the reflection on liquids. The recently reported results for the neutron's electric polarizability and the neutron-electron scattering length are supported by the Bi- and Pb-scattering length of this work. (orig.).
Optical scattering lengths in large liquid-scintillator neutrino detectors
Energy Technology Data Exchange (ETDEWEB)
Wurm, M.; Feilitzsch, F. von; Goeger-Neff, M.; Hofmann, M.; Lewke, T.; Meindl, Q.; Moellenberg, R.; Oberauer, L.; Potzel, W.; Tippmann, M.; Todor, S.; Winter, J. [Physik-Department E15, Technische Universitaet Muenchen, James-Franck-Str., D-85748 Garching (Germany); Lachenmaier, T.; Traunsteiner, C. [Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstr. 2, D-85748 Garching (Germany); Undagoitia, T. Marrodan [Physik-Department E15, Technische Universitaet Muenchen, James-Franck-Str., D-85748 Garching (Germany); Physik-Institut, Universitaet Zuerich, Winterthurstr. 189, CH-8057 Zuerich (Switzerland)
2010-05-15
For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents phenylxylylethane, linear alkylbenzene (LAB), and dodecane, which are under discussion for next-generation experiments such as SNO+ (Sudbury Neutrino Observatory), HanoHano, or LENA (Low Energy Neutrino Astronomy). Results comprise the wavelength range of 415-440 nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.
Optical scattering lengths in large liquid-scintillator neutrino detectors.
Wurm, M; von Feilitzsch, F; Göger-Neff, M; Hofmann, M; Lachenmaier, T; Lewke, T; Marrodán Undagoitia, T; Meindl, Q; Möllenberg, R; Oberauer, L; Potzel, W; Tippmann, M; Todor, S; Traunsteiner, C; Winter, J
2010-05-01
For liquid-scintillator neutrino detectors of kiloton scale, the transparency of the organic solvent is of central importance. The present paper reports on laboratory measurements of the optical scattering lengths of the organic solvents phenylxylylethane, linear alkylbenzene (LAB), and dodecane, which are under discussion for next-generation experiments such as SNO+ (Sudbury Neutrino Observatory), HanoHano, or LENA (Low Energy Neutrino Astronomy). Results comprise the wavelength range of 415-440 nm. The contributions from Rayleigh and Mie scattering as well as from absorption/re-emission processes are discussed. Based on the present results, LAB seems to be the preferred solvent for a large-volume detector.
Coulomb corrections to scattering length and effective radius
International Nuclear Information System (INIS)
Mur, V.D.; Kudryavtsev, A.E.; Popov, V.S.
1983-01-01
The problem considered is extraction of the ''purely nuclear'' scattering length asub(s) (corresponding to the strong potential Vsub(s) at the Coulomb interaction switched off) from the Coulomb-nuclear scattering length asub(cs), which is an object of experimental measurement. The difference between asub(s) and asub(cs) is especially large if the potential Vsub(s) has a level (real or virtual) with an energy close to zero. For this case formulae are obtained relating the scattering lengths asub(s) and asub(cs), as well as the effective radii rsub(s) and rsub(cs). The results are extended to states with arbitrary angular momenta l. It is shown that the Coulomb correction is especially large for the coefficient with ksup(2l) in the expansion of the effective radius; in this case the correction contains a large logarithm ln(asub(B)/rsub(0)). The Coulomb renormalization of other terms in the effective radius espansion is of order (rsub(0)/asub(B)), where r 0 is the nuclear force radius, asub(B) is the Bohr radius. The obtained formulae are tried on a number of model potentials Vsub(s), used in nuclear physics
Measuring spin-dependent structure functions at CEBAF
Energy Technology Data Exchange (ETDEWEB)
Schaefer, A. [Universitaet Frankfurt (Germany)
1994-04-01
The author analyses whether CEBAF with a 10 GeV beam could contribute significantly to the understanding of spin-dependent deep-inelastic scattering as well as semi-inclusive reactions. The main advantage of CEBAF is the much better attainable statistics, its great disadvantage its comparably low energy, which limits the accessible x-range to about 0.15 to 0.7. Within these constraints CEBAF could provide (1) high precision data which would be very valuable to understand the Q{sup 2} dependence of the spin-dependent structure functions g{sub 1}(x) and G{sub 2}(x) and (2) the by far most precise determination of the third moments of g{sub 1}(x) and g{sub 2}(x) the latter of which the author argues to be related to a fundamental property of the nucleon.
Measuring spin-dependent structure functions at CEBAF
International Nuclear Information System (INIS)
Schaefer, A.
1994-01-01
The author analyses whether CEBAF with a 10 GeV beam could contribute significantly to the understanding of spin-dependent deep-inelastic scattering as well as semi-inclusive reactions. The main advantage of CEBAF is the much better attainable statistics, its great disadvantage its comparably low energy, which limits the accessible x-range to about 0.15 to 0.7. Within these constraints CEBAF could provide (1) high precision data which would be very valuable to understand the Q 2 dependence of the spin-dependent structure functions g 1 (x) and G 2 (x) and (2) the by far most precise determination of the third moments of g 1 (x) and g 2 (x) the latter of which the author argues to be related to a fundamental property of the nucleon
Atom-dimer scattering in a heteronuclear mixture with a finite intraspecies scattering length
Gao, Chao; Zhang, Peng
2018-04-01
We study the three-body problem of two ultracold identical bosonic atoms (denoted by B ) and one extra atom (denoted by X ), where the scattering length aB X between each bosonic atom and atom X is resonantly large and positive. We calculate the scattering length aad between one bosonic atom and the shallow dimer formed by the other bosonic atom and atom X , and investigate the effect induced by the interaction between the two bosonic atoms. We find that even if this interaction is weak (i.e., the corresponding scattering length aB B is of the same order of the van der Waals length rvdW or even smaller), it can still induce a significant effect for the atom-dimer scattering length aad. Explicitly, an atom-dimer scattering resonance can always occur when the value of aB B varies in the region with | aB B|≲ rvdW . As a result, both the sign and the absolute value of aad, as well as the behavior of the aad-aB X function, depends sensitively on the exact value of aB B. Our results show that, for a good quantitative theory, the intraspecies interaction is required to be taken into account for this heteronuclear system, even if this interaction is weak.
Nucleon-nucleon scattering length from three-body reactions
International Nuclear Information System (INIS)
Bodek, K.
1989-01-01
Experiments aimed at the measurement of the singlet scattering lengths 1 a np and 1 a nn of the NN-interaction in the presence of a heavy spectator are described. The values obtained are compared with the results of measurements of other reactions. The very good agreement of the experimental values of 1 a np from all breakup reactions and elastic scattering as well as agreement of the values of 1 a nn from breakup reactions and disagreement with the value from the π - d → nnγ reaction cast doubts on the hypothesis ascribing this discrepancy to a 3N-force. This result also suggests a stronger effect of a violation of the charge independence principle than previously accepted. 101 refs., 18 figs., 3 tabs. (author)
Scattering Length Scaling Laws for Ultracold Three-Body Collisions
International Nuclear Information System (INIS)
D'Incao, J.P.; Esry, B.D.
2005-01-01
We present a simple and unifying picture that provides the energy and scattering length dependence for all inelastic three-body collision rates in the ultracold regime for three-body systems with short-range two-body interactions. Here, we present the scaling laws for vibrational relaxation, three-body recombination, and collision-induced dissociation for systems that support s-wave two-body collisions. These systems include three identical bosons, two identical bosons, and two identical fermions. Our approach reproduces all previous results, predicts several others, and gives the general form of the scaling laws in all cases
Assessing Telomere Length Using Surface Enhanced Raman Scattering
Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Cui, Yiping
2014-11-01
Telomere length can provide valuable insight into telomeres and telomerase related diseases, including cancer. Here, we present a brand-new optical telomere length measurement protocol using surface enhanced Raman scattering (SERS). In this protocol, two single strand DNA are used as SERS probes. They are labeled with two different Raman molecules and can specifically hybridize with telomeres and centromere, respectively. First, genome DNA is extracted from cells. Then the telomere and centromere SERS probes are added into the genome DNA. After hybridization with genome DNA, excess SERS probes are removed by magnetic capturing nanoparticles. Finally, the genome DNA with SERS probes attached is dropped onto a SERS substrate and subjected to SERS measurement. Longer telomeres result in more attached telomere probes, thus a stronger SERS signal. Consequently, SERS signal can be used as an indicator of telomere length. Centromere is used as the inner control. By calibrating the SERS intensity of telomere probe with that of the centromere probe, SERS based telomere measurement is realized. This protocol does not require polymerase chain reaction (PCR) or electrophoresis procedures, which greatly simplifies the detection process. We anticipate that this easy-operation and cost-effective protocol is a fine alternative for the assessment of telomere length.
Universality in few-body systems with large scattering length
International Nuclear Information System (INIS)
Hammer, H.-W.
2005-01-01
Effective Field Theory (EFT) provides a powerful framework that exploits a separation of scales in physical systems to perform systematically improvable, model-independent calculations. Particularly interesting are few-body systems with short-range interactions and large two-body scattering length. Such systems display remarkable universal features. In systems with more than two particles, a three-body force with limit cycle behavior is required for consistent renormalization already at leading order. We will review this EFT and some of its applications in the physics of cold atoms and nuclear physics. In particular, we will discuss the possibility of an infrared limit cycle in QCD. Recent extensions of the EFT approach to the four-body system and N-boson droplets in two spatial dimensions will also be addressed
Spin-dependent optics with metasurfaces
Directory of Open Access Journals (Sweden)
Xiao Shiyi
2016-11-01
Full Text Available Optical spin-Hall effect (OSHE is a spin-dependent transportation phenomenon of light as an analogy to its counterpart in condensed matter physics. Although being predicted and observed for decades, this effect has recently attracted enormous interests due to the development of metamaterials and metasurfaces, which can provide us tailor-made control of the light-matter interaction and spin-orbit interaction. In parallel to the developments of OSHE, metasurface gives us opportunities to manipulate OSHE in achieving a stronger response, a higher efficiency, a higher resolution, or more degrees of freedom in controlling the wave front. Here, we give an overview of the OSHE based on metasurface-enabled geometric phases in different kinds of configurational spaces and their applications on spin-dependent beam steering, focusing, holograms, structured light generation, and detection. These developments mark the beginning of a new era of spin-enabled optics for future optical components.
International Nuclear Information System (INIS)
Rupnik, K.; Asaf, U.; McGlynn, S.P.
1990-01-01
A linear correlation exists between the electron scattering length, as measured by a pressure shift method, and the polarizabilities for He, Ne, Ar, Kr, and Xe gases. The correlative algorithm has excellent predictive capability for the electron scattering lengths of mixtures of rare gases, simple molecular gases such as H 2 and N 2 and even complex molecular entities such as methane, CH 4
Spin-dependent Nucleon Structure Studies at MIT/Bates
International Nuclear Information System (INIS)
Botto, T.
2005-01-01
We present preliminary results from recent measurements of the proton, neutron and deuterium electro-magnetic form factors obtained by the BLAST collaboration at the MIT/Bates Linear Accelerator Facility. BLAST (Bates Large Acceptance Spectrometer Toroid) is a large-acceptance multi-purpose detector dedicated to studies of exclusive spin-dependent electron scattering from internal polarized targets. BLAST makes use of stored electron beam currents in excess of 150 mA with a 60-70% polarization. The electron beam is let through a 15 mm diameter, 60 cm long open-ended storage cell which is fed with ultra-pure, high-polarization H1,D1 gas from an Atomic Beam Source. The target polarization can be rapidly reversed between different vector and tensor target states, thus minimizing systematic uncertainties. The target spin can be oriented to any in-plane direction via a set of Helmholtz coils. Target polarizations in the storage cell of up to 80% (vector) and 70% (tensor) have been routinely achieved over a period of several months. Our data on the D-vector(e-vector,e'n) reaction off vector polarized deuterium allow for a unique extraction of the neutron charge form factor G E n . At same time, complementary measurements of G M n , T20 and the spin-dependent nucleon momentum distributions in deuterium are obtained via the D-vector(e-vector,e'), D (e-vector,e'd) and D (e-vector,e'p) reactions. In addition, BLAST data on vector polarized hydrogen will provide novel measurements of the GE/GM form-factor ratio on the proton as well as of the spin-dependent electro-excitation of the Δ(1232) resonance. Such comprehensive program on few body physics is now well underway and preliminary data will be presented
Precision measurement of the neutron spin dependent structure functions
International Nuclear Information System (INIS)
Kolomensky, Y.G.
1997-02-01
In experiment E154 at the Stanford Linear Accelerator Center the spin dependent structure function g 1 n (x, Q 2 ) of the neutron was measured by scattering longitudinally polarized 48.3 GeV electrons off a longitudinally polarized 3 He target. The high beam energy allowed the author to extend the kinematic coverage compared to the previous SLAC experiments to 0.014 ≤ x ≤ 0.7 with an average Q 2 of 5 GeV 2 . The author reports the integral of the spin dependent structure function in the measured range to be ∫ 0.014 0.7 dx g 1 n (x, 5 GeV 2 ) = -0.036 ± 0.004(stat.) ± 0.005(syst.). The author observes relatively large values of g 1 n at low x that call into question the reliability of data extrapolation to x → 0. Such divergent behavior disagrees with predictions of the conventional Regge theory, but is qualitatively explained by perturbative QCD. The author performs a Next-to-Leading Order perturbative QCD analysis of the world data on the nucleon spin dependent structure functions g 1 p and g 1 n paying careful attention to the experimental and theoretical uncertainties. Using the parameterizations of the helicity-dependent parton distributions obtained in the analysis, the author evolves the data to Q 2 = 5 GeV 2 , determines the first moments of the polarized structure functions of the proton and neutron, and finds agreement with the Bjorken sum rule
Petoukhova, A. L.; Steenbergen, W.; van Leeuwen, T. G.; de Mul, F. F. M.
2002-01-01
A low coherence Mach-Zehnder interferometer is developed for path length resolved dynamic light scattering in highly turbid media. The path length distribution of multiply scattered photons in Intralipid is changed by the addition of absorbing dyes. Path length distributions obtained for various
Extracting $p\\Lambda$ scattering lengths from heavy ion collisions
Shapoval, V M; Lednicky, R; Sinyukov, Yu M
2015-01-01
The $p-\\Lambda \\oplus \\bar{p}-\\bar{\\Lambda}$ and $\\bar{p}-\\Lambda \\oplus p-\\bar{\\Lambda}$ correlation functions for 10% most central Au+Au collisions at top RHIC energy $\\sqrt{s_{NN}}=200$ GeV are modeled with Lednicky and Lyuboshitz analytical formula using the source radii extracted from the hydrokinetic model (HKM) simulations. For the baryon-antibaryon case the corresponding spin-averaged strong interaction scattering length is obtained by fitting the STAR correlation function. In contrast to the experimental results, where extracted $p\\bar{\\Lambda}$ source radius value was found $\\sim 2$ times smaller than the corresponding $p\\Lambda$ one, the calculations in HKM show both $p\\Lambda$ and $p\\bar{\\Lambda}$ effective source radii to be quite close, as expected from theoretical considerations. To obtain the satisfactory fit to the measured baryon-antibaryon correlation function at this large source radius value, the modified analytical approximation to the correlation function, effectively accounting for the...
The TUNL neutron-neutron scattering length experiment
International Nuclear Information System (INIS)
Trotter, D.E.G.; Tornow, W.; Howell, C.R.
1995-01-01
Since an accurate value for the neutron-neutron (nn) scattering length a nn is of fundamental interest, its determination should not rely on one source of experimental information only. Besides the π d capture reaction, the nd breakup reaction has been the classical reaction used for determining a nn . However, none of the published values for a nn obtained from kinematically complete nd → n+n+p breakup data are based on a rigorous treatment of the three-nucleon continuum. In addition, the scale uncertainty associated with the existing nd breakup cross-section data in the region of the nn final-state interaction peak is too large to allow for a meaningful reanalysis. Therefore, a new kinematically complete nd breakup experiment is underway at TUNL at an incident neutron energy of 13 MeV. State-of-the-art three-nucleon continuum calculations will be used to analyze the data. In order to investigate the possible influence of three-nucleon force effects, a nn will be determined from data taken at four production angles of the nn pair between 20.5 degrees and 43 degrees (lab)
Longitudinal spin dependence of massive lepton pair production
International Nuclear Information System (INIS)
Berger, E. L.; Gordon, L. E.; Klasen, M.
2000-01-01
In this paper, the authors summarize recent work in which they demonstrate that the Compton subprocess, q + g -> γ* + q also dominates the Drell-Yan cross section in polarized and unpolarized proton-proton reactions for values of the transverse momentum Q T of the pair that are larger than roughly half of the pair mass Q, Q T > Q/2. The Drell-Yan process is therefore a valuable, heretofore overlooked, independent source of constraints on the spin-averaged and spin-dependent gluon densities. Although the Drell-Yan cross section is smaller than the prompt photon cross section, massive lepton pair production is cleaner theoretically since long-range fragmentation contributions are absent as are the experimental and theoretical complications associated with isolation of the real photon. Moreover, the dynamics of spin-dependence in hard-scattering processes is a sufficiently complex topic, and its understanding at an early stage in its development, that several defensible approaches for extracting polarized parton densities deserve to be pursued with the expectation that consistent results must emerge
The spin dependent odderon in the diquark model
Energy Technology Data Exchange (ETDEWEB)
Szymanowski, Lech [National Centre for Nuclear Research (NCBJ), Warsaw (Poland); Zhou, Jian, E-mail: jzhou@sdu.edu.cn [School of Physics, & Key Laboratory of Particle Physics and Particle Irradiation (MOE), Shandong University, Jinan, Shandong 250100 (China); Nikhef and Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, NL-1081 HV Amsterdam (Netherlands)
2016-09-10
In this short note, we report a di-quark model calculation for the spin dependent odderon and demonstrate that the asymmetrical color source distribution in the transverse plane of a transversely polarized hadron plays an essential role in yielding the spin dependent odderon. This calculation confirms the earlier finding that the spin dependent odderon is closely related to the parton orbital angular momentum.
Neutron-triton scattering lengths for interactions reproducing low-energy trinucleon data
International Nuclear Information System (INIS)
Levashev, V.P.
1981-01-01
By solving the integral equations for four nucleons the neutron-triton scattering lengths and total cross section are calculated using different S-wave rank-one separable potentials. A number of linear correlations between the neutron-triton scattering lengths and triton binding energy are found. The scattering lengths consistent with low-energy trinucleon data. The results obtained are compared with available experimental data [ru
Analysis of an atom laser based on the spatial control of the scattering length
International Nuclear Information System (INIS)
Carpentier, Alicia V.; Michinel, Humberto; Rodas-Verde, Maria I.; Perez-Garcia, Victor M.
2006-01-01
In this paper we analyze atom lasers based on the spatial modulation of the scattering length of a Bose-Einstein condensate. We demonstrate, through numerical simulations and approximate analytical methods, the controllable emission of matter-wave bursts and study the dependence of the process on the spatial shape of the scattering length along the axis of emission. We also study the role of an additional modulation of the scattering length in time
Spin-dependent potentials from lattice QCD
International Nuclear Information System (INIS)
Koma, Y.
2006-09-01
The spin-dependent corrections to the static inter-quark potential are phenomenologically relevant to describing the fine and hyperfine spin splitting of the heavy quarkonium spectra. We investigate these corrections, which are represented as the field strength correlators on the quark-antiquark source, in SU(3) lattice gauge theory. We use the Polyakov loop correlation function as the quark-antiquark source, and by employing the multi-level algorithm, we obtain remarkably clean signals for these corrections up to intermediate distances of around 0.6 fm. Our observation suggests several new features of the corrections. (orig.)
Bottom quark contribution to spin-dependent dark matter detection
Directory of Open Access Journals (Sweden)
Jinmian Li
2016-05-01
Full Text Available We investigate a previously overlooked bottom quark contribution to the spin-dependent cross section for Dark Matter (DM scattering from the nucleon. While the mechanism is relevant to any supersymmetric extension of the Standard Model, for illustrative purposes we explore the consequences within the framework of the Minimal Supersymmetric Standard Model (MSSM. We study two cases, namely those where the DM is predominantly Gaugino or Higgsino. In both cases, there is a substantial, viable region in parameter space (mb˜−mχ≲O(100 GeV in which the bottom contribution becomes important. We show that a relatively large contribution from the bottom quark is consistent with constraints from spin-independent DM searches, as well as some incidental model dependent constraints.
A method to measure the antikaon-nucleon scattering length in lattice QCD
International Nuclear Information System (INIS)
Lage, Michael; Meissner, Ulf-G.; Rusetsky, Akaki
2009-01-01
We propose a method to determine the isoscalar K-bar N scattering length on the lattice. Our method represents the generalization of Luescher's approach in the presence of inelastic channels (complex scattering length). In addition, the proposed approach allows one to find the position of the S-matrix pole corresponding the Λ(1405) resonance.
International Nuclear Information System (INIS)
Saha, H.P.
1993-01-01
The multiconfiguration Hartree-Fock method for continuum wave functions has been used to calculate the scattering length and phase shifts over extremely low energies ranging from 0 to 1 eV very accurately for electron-helium scattering. The scattering length is calculated very accurately with wave functions computed exactly at zero energy, resulting in an upper bound of 1.1784. The electron correlation and polarization of the target by the scattering electron, which are very important in these calculations, have been taken into account in an accurate ab initio manner through the configuration-interaction procedure by optimizing both bound and continuum orbitals simultaneously at each kinetic energy of the scattered electron. Detailed results for scattering length, differential, total, and momentum-transfer cross sections obtained from the phase shifts are presented. The present scattering length is found to be in excellent agreement with the experimental result of Andrick and Bitsch [J. Phys. B 8, 402 (1975)] and the theoretical result of O'Malley, Burke, and Berrington [J. Phys. B 12, 953 (1979)]. There is excellent agreement between the present total cross sections and the corresponding experimental measurements of Buckman and Lohmann [J. Phys. B 19, 2547 (1986)]. The present momentum-transfer cross sections also show remarkable agreement with the experimental results of Crompton, Elford, and Robertson [Aust. J. Phys. 23, 667 (1970)
Scattering-matrix elements of coated infinite-length cylinders
International Nuclear Information System (INIS)
Manickavasagam, S.; Menguec, M.P.
1998-01-01
The angular variations of scattering-matrix elements of coated cylindrical particles are presented. The sensitivity of different elements for a number of physical parameters are discussed, including size parameter, real and imaginary parts of the refractive index of the outer coat, and the inner core. The numerical predictions are presented for typical index-of-refraction values of cotton fibers. These results show that the physical structure of coated cylinders can be determined from carefully conducted light-scattering experiments. copyright 1998 Optical Society of America
Petoukhova, Anna; Steenbergen, Wiendelt; van Leeuwen, Ton; de Mul, F.F.M.
2002-01-01
A low coherence Mach–Zehnder interferometer is developed for path length resolved dynamic light scattering in highly turbid media. The path length distribution of multiply scatteredphotons in Intralipid is changed by the addition of absorbing dyes. Path length distributions obtained for various
πd scattering lengths taking into account the pion and nucleon mass differences
International Nuclear Information System (INIS)
Pupyshev, V.V.; Rakityanskii, S.A.
1985-01-01
The scattering lengths and s-wave phase shifts for πd elastic scattering are calculated in the framework of an isotopically noninvariant approach that takes into account the mass splitting of the pionic and nucleonic isomultiplets. It is shown that the particle mass differences lead to appearance of the imaginary parts in the πd scattering lengths (approx.10 -4 fm) not associated with pion absorption. The sensitivity of the mass-difference effects to variation of the parameters of the πN potential is studied and turns out to be small
CNI polarimetry and the hadronic spin dependence of pp scattering
International Nuclear Information System (INIS)
Trueman, T.L.
1996-01-01
Methods for limiting the size of hadronic spin-flip in the Coulomb- Nuclear Interference. region are critically assessed. This work was presented at the High Energy Polarimetry Workshop in Amsterdam, Sept. 9, 1996 and the RHIC Spin Collaboration meeting in Marseille, Sept. 17, 1996
Measurement of the Rayleigh scattering length in liquid scintillators for JUNO
Energy Technology Data Exchange (ETDEWEB)
Hackspacher, Paul [Johannes Gutenberg-Universitaet Mainz, PRISMA Excellence Cluster (Germany); Collaboration: JUNO-Collaboration
2016-07-01
In liquid scintillator neutrino detectors such as the upcoming Jiangmen Underground Neutrino Observatory (JUNO), neutrino interactions are being detected by means of inverse beta decay and analysis of the resulting luminescent light. In order to reliably reconstruct these events from photomultiplier signals, the scattering properties of the detector materials need to be sufficiently well known. In the LAB-based liquid scintillator that has been proposed for JUNO, the primary contribution to the scattering process comes from Rayleigh scattering. The characteristic Rayleigh scattering length can be experimentally obtained in an optical laboratory setup. This talk presents the approach, the current status and the future plans of the experiment.
International Nuclear Information System (INIS)
Verhaar, B.J.; de Goey, L.P.H.; Vredenbregt, E.J.D.
1985-01-01
The concepts of scattering length a and effective range r/sub e/ previously introduced for low-energy scattering from a potential V(r) in a plane and in higher dimensions are extended to include a 1/r potential (strength parameter γ). Both a and r/sub e/ have the physical significance of being equal to the radius of an equivalent hard sphere giving rise to the same O(k 0 ) and O(k 2 ) terms in the expression for the phase shift. The method used is based on the properties of the ''local scattering length'' a(r,γ) for the potential V(r) cut off at radius r and an ''equivalent hard-sphere radius'' a(r,k,γ) for wave number knot =0. It is shown that these quantities have a smooth behavior for γ→0 and for dimension n→2
Spin-dependent parton distributions in the nucleon
Energy Technology Data Exchange (ETDEWEB)
Cloet, I.C. [Special Research Centre for the Subatomic Structure of Matter and Department of Physics and Mathematical Physics, University of Adelaide, SA 5005 (Australia); Bentz, W. [Department of Physics, School of Science, Tokai University Hiratsuka-shi, Kanagawa 259-1292 (Japan); Thomas, A.W. [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)
2005-04-15
Spin-dependent quark light-cone momentum distributions are calculated for a nucleon in the nuclear medium. We utilize a modified NJL model where the nucleon is described as a composite quark-diquark state. Scalar and vector mean fields are incorporated in the nuclear medium and these fields couple to the confined quarks in the nucleon. The effect of these fields on the spin-dependent distributions and consequently the axial charges is investigated. Our results for the 'spin-dependent EMC effect' are also discussed.
Spin-Dependent Transport through Chiral Molecules Studied by Spin-Dependent Electrochemistry
2016-01-01
Conspectus Molecular spintronics (spin + electronics), which aims to exploit both the spin degree of freedom and the electron charge in molecular devices, has recently received massive attention. Our recent experiments on molecular spintronics employ chiral molecules which have the unexpected property of acting as spin filters, by way of an effect we call “chiral-induced spin selectivity” (CISS). In this Account, we discuss new types of spin-dependent electrochemistry measurements and their use to probe the spin-dependent charge transport properties of nonmagnetic chiral conductive polymers and biomolecules, such as oligopeptides, L/D cysteine, cytochrome c, bacteriorhodopsin (bR), and oligopeptide-CdSe nanoparticles (NPs) hybrid structures. Spin-dependent electrochemical measurements were carried out by employing ferromagnetic electrodes modified with chiral molecules used as the working electrode. Redox probes were used either in solution or when directly attached to the ferromagnetic electrodes. During the electrochemical measurements, the ferromagnetic electrode was magnetized either with its magnetic moment pointing “UP” or “DOWN” using a permanent magnet (H = 0.5 T), placed underneath the chemically modified ferromagnetic electrodes. The spin polarization of the current was found to be in the range of 5–30%, even in the case of small chiral molecules. Chiral films of the l- and d-cysteine tethered with a redox-active dye, toludin blue O, show spin polarizarion that depends on the chirality. Because the nickel electrodes are susceptible to corrosion, we explored the effect of coating them with a thin gold overlayer. The effect of the gold layer on the spin polarization of the electrons ejected from the electrode was investigated. In addition, the role of the structure of the protein on the spin selective transport was also studied as a function of bias voltage and the effect of protein denaturation was revealed. In addition to
Moments of nucleon spin-dependent generalized parton distributions
International Nuclear Information System (INIS)
Schroers, W.; Brower, R.C.; Dreher, P.; Edwards, R.; Fleming, G.; Haegler, Ph.; Heller, U.M.; Lippert, Th.; Negele, J.W.; Pochinsky, A.V.; Renner, D.B.; Richards, D.; Schilling, K.
2004-01-01
We present a lattice measurement of the first two moments of the spin-dependent GPD H∼(x, ξ, t). From these we obtain the axial coupling constant and the second moment of the spin-dependent forward parton distribution. The measurements are done in full QCD using Wilson fermions. In addition, we also present results from a first exploratory study of full QCD using Asqtad sea and domain-wall valence fermions
Impact of hadronic and nuclear corrections on global analysis of spin-dependent parton distributions
Energy Technology Data Exchange (ETDEWEB)
Jimenez-Delgado, Pedro [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Accardi, Alberto [Hampton University, Hampton, VA (United States); Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Melnitchouk, Wally [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
2014-02-01
We present the first results of a new global next-to-leading order analysis of spin-dependent parton distribution functions from the most recent world data on inclusive polarized deep-inelastic scattering, focusing in particular on the large-x and low-Q^2 regions. By directly fitting polarization asymmetries we eliminate biases introduced by using polarized structure function data extracted under nonuniform assumptions for the unpolarized structure functions. For analysis of the large-x data we implement nuclear smearing corrections for deuterium and 3He nuclei, and systematically include target mass and higher twist corrections to the g_1 and g_2 structure functions at low Q^2. We also explore the effects of Q^2 and W^2 cuts in the data sets, and the potential impact of future data on the behavior of the spin-dependent parton distributions at large x.
Isospin breaking in the pion-nucleon coupling constant and the nucleon-nucleon scattering length
Directory of Open Access Journals (Sweden)
V. A. Babenko
2016-08-01
Full Text Available Charge independence breaking (CIB in the pion-nucleon coupling constant and the nucleon-nucleon scattering length is considered on the basis of the Yukawa meson theory. CIB effect in these quantities is almost entirely explained by the mass difference between the charged and the neutral pions. Therewith charge splitting of the pion-nucleon coupling constant is almost the same as charge splitting of the pion mass. Calculated difference between the proton-proton and the neutron-proton scattering length in this case comprises ∼90% of the experimental value.
Constant scattering length fits to low energy K-p interactions
International Nuclear Information System (INIS)
Conboy, J.E.
1985-10-01
The paper concerns the data on low energy K - p interactions analysed using the constant scattering length (C.S.L.) approximation. The scattering lengths are found to differ significantly from those required to fit data from previous K -1 p experiments, and these differences are discussed. The data indicate an Tspin=1 P- wave interaction, from the production angle distributions of the K-bar 0 n, Σ +- π -+ and Λπ 0 channels. However the authors have been unable to fit both the P-wave and K 0 sub(L)p data with the simple C.S.L. model. (U.K.)
Determination of the negatively charged pion-proton scattering length from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2003-01-01
We derive a closed, model independent, expression for the electromagnetic correction factor to the hadronic scattering length extracted from a hydrogenic atom with an extended charge and in the limit of a short ranged hadronic interaction to terms of order ((alpha)**2)(log(alpha)) in the limit of a non-relativistic approach. A hadronic negatively charged pion-proton scattering length of 0.0870(5), in units of inverse charged pion-mass, is deduced, leading to a pion-nucleon coupling constant from the GMO relation equals to 14.00(19).
A phenomenological determination of the pion-nucleon scattering lengths from pionic hydrogen
Ericson, Torleif Eric Oskar; Wycech, S
2005-01-01
A model independent expression for the electromagnetic corrections to a phenomenological hadronic pion-nucleon scattering length, extracted from pionic hydrogen, is obtained. In a non-relativistic approach and using an extended charge distribution, these corrections are derived up to terms of order (alpha)**2 log(alpha) in the limit of a short-range hadronic interaction. We infer a charged pion-proton scattering length of 0.0870(5) in units of inverse pion mass, which gives for the charged pion-proton-neutron coupling, through the GMO relation, a value of 14.04(17).
Energy Technology Data Exchange (ETDEWEB)
Baru, V. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Theoretical and Experimental Physics, B. Cheremushinskaya 25, 117218 Moscow (Russian Federation); Hanhart, C. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Hoferichter, M.; Kubis, B. [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Nogga, A. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Phillips, D.R., E-mail: phillips@phy.ohiou.ed [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institute of Nuclear and Particle Physics and Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States)
2011-01-03
We present a calculation of the {pi}{sup -}d scattering length with an accuracy of a few percent using chiral perturbation theory. For the first time isospin-violating corrections are included consistently. Using data on pionic deuterium and pionic hydrogen atoms, we extract the isoscalar and isovector pion-nucleon scattering lengths and obtain a{sup +}=(7.6{+-}3.1).10{sup -3}M{sub {pi}}{sup -1} and a{sup -}=(86.1{+-}0.9).10{sup -3}M{sub {pi}}{sup -1}. Via the Goldberger-Miyazawa-Oehme sum rule, this leads to a charged-pion-nucleon coupling constant g{sub c}{sup 2}/4{pi}=13.69{+-}0.20.
Quantum scattering in one-dimensional systems satisfying the minimal length uncertainty relation
Energy Technology Data Exchange (ETDEWEB)
Bernardo, Reginald Christian S., E-mail: rcbernardo@nip.upd.edu.ph; Esguerra, Jose Perico H., E-mail: jesguerra@nip.upd.edu.ph
2016-12-15
In quantum gravity theories, when the scattering energy is comparable to the Planck energy the Heisenberg uncertainty principle breaks down and is replaced by the minimal length uncertainty relation. In this paper, the consequences of the minimal length uncertainty relation on one-dimensional quantum scattering are studied using an approach involving a recently proposed second-order differential equation. An exact analytical expression for the tunneling probability through a locally-periodic rectangular potential barrier system is obtained. Results show that the existence of a non-zero minimal length uncertainty tends to shift the resonant tunneling energies to the positive direction. Scattering through a locally-periodic potential composed of double-rectangular potential barriers shows that the first band of resonant tunneling energies widens for minimal length cases when the double-rectangular potential barrier is symmetric but narrows down when the double-rectangular potential barrier is asymmetric. A numerical solution which exploits the use of Wronskians is used to calculate the transmission probabilities through the Pöschl–Teller well, Gaussian barrier, and double-Gaussian barrier. Results show that the probability of passage through the Pöschl–Teller well and Gaussian barrier is smaller in the minimal length cases compared to the non-minimal length case. For the double-Gaussian barrier, the probability of passage for energies that are more positive than the resonant tunneling energy is larger in the minimal length cases compared to the non-minimal length case. The approach is exact and applicable to many types of scattering potential.
Impact of Disorder on Spin Dependent Transport Phenomena
Saidaoui, Hamed
2016-07-03
The impact of the spin degree of freedom on the transport properties of electrons traveling through magnetic materials has been known since the pioneer work of Mott [1]. Since then it has been demonstrated that the spin angular momentum plays a key role in the scattering process of electrons in magnetic multilayers. This role has been emphasized by the discovery of the Giant Magnetoresistance in 1988 by Fert and Grunberg [2, 3]. Among the numerous applications and effects that emerged in mesoscopic devices two mechanisms have attracted our attention during the course of this thesis: the spin transfer torque and the spin Hall effects. The former consists in the transfer of the spin angular momentum from itinerant carriers to local magnetic moments [4]. This mechanism results in the current-driven magnetization switching and excitations, which has potential application in terms of magnetic data storage and non-volatile memories. The latter, spin Hall effect, is considered as well to be one of the most fascinating mechanisms in condensed matter physics due to its ability of generating non-equilibrium spin currents without the need for any magnetic materials. In fact the spin Hall effect relies only on the presence of the spin-orbit interaction in order to create an imbalance between the majority and minority spins. The objective of this thesis is to investigate the impact of disorder on spin dependent transport phenomena. To do so, we identified three classes of systems on which such disorder may have a dramatic influence: (i) antiferromagnetic materials, (ii) impurity-driven spin-orbit coupled systems and (iii) two dimensional semiconducting electron gases with Rashba spin-orbit coupling. Antiferromagnetic materials - We showed that in antiferromagnetic spin-valves, spin transfer torque is highly sensitive to disorder, which prevents its experimental observation. To solve this issue, we proposed to use either a tunnel barrier as a spacer or a local spin torque using
Energy Technology Data Exchange (ETDEWEB)
Baru, V. [Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44870 Bochum (Germany); Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Theoretical and Experimental Physics, B. Cheremushinskaya 25, 117218 Moscow (Russian Federation); Hanhart, C. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Hoferichter, M., E-mail: hoferichter@hiskp.uni-bonn.de [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Institute of Nuclear and Particle Physics and Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States); Kubis, B. [Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Universitaet Bonn, D-53115 Bonn (Germany); Nogga, A. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2011-12-15
We use chiral perturbation theory (ChPT) to calculate the {pi}{sup -}d scattering length with an accuracy of a few percent, including isospin-violating corrections in both the two- and three-body sectors. In particular, we provide the technical details of a recent letter (Baru et al., 2011) , where we used data on pionic deuterium and pionic hydrogen atoms to extract the isoscalar and isovector pion-nucleon scattering lengths a{sup +} and a{sup -}. We study isospin-breaking contributions to the three-body part of a{sub {pi}}{sup -}{sub d} due to mass differences, isospin violation in the {pi}N scattering lengths, and virtual photons. This last class of effects is ostensibly infrared enhanced due to the smallness of the deuteron binding energy. However, we show that the leading virtual-photon effects that might undergo such enhancement cancel, and hence the standard ChPT counting provides a reliable estimate of isospin violation in a{sub {pi}}{sup -}{sub d} due to virtual photons. Finally, we discuss the validity of the Goldberger-Miyazawa-Oehme sum rule in the presence of isospin violation, and use it to determine the charged-pion-nucleon coupling constant.
Precision calculation of threshold πd scattering, πN scattering lengths, and the GMO sum rule
Baru, V.; Hanhart, C.; Hoferichter, M.; Kubis, B.; Nogga, A.; Phillips, D. R.
2011-12-01
We use chiral perturbation theory (ChPT) to calculate the πd scattering length with an accuracy of a few percent, including isospin-violating corrections in both the two- and three-body sectors. In particular, we provide the technical details of a recent letter (Baru et al., 2011) [1], where we used data on pionic deuterium and pionic hydrogen atoms to extract the isoscalar and isovector pion-nucleon scattering lengths a and a. We study isospin-breaking contributions to the three-body part of a due to mass differences, isospin violation in the πN scattering lengths, and virtual photons. This last class of effects is ostensibly infrared enhanced due to the smallness of the deuteron binding energy. However, we show that the leading virtual-photon effects that might undergo such enhancement cancel, and hence the standard ChPT counting provides a reliable estimate of isospin violation in a due to virtual photons. Finally, we discuss the validity of the Goldberger-Miyazawa-Oehme sum rule in the presence of isospin violation, and use it to determine the charged-pion-nucleon coupling constant.
Determination of the pion-nucleon coupling constant and scattering lengths
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Thomas, A.W.
2002-01-01
We critically evaluate the isovector Goldberger-Miyazawa-Oehme (GMO) sum rule for forward πN scattering using the recent precision measurements of π - p and π - d scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data, g c 2 (GMO)/4π=14.11±0.05(statistical)±0.19(systematic) or f c 2 /4π=0.0783(11). This value is intermediate between that of indirect methods and the direct determination from backward np differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the pion-proton and pion-neutron scattering lengths with high precision, namely, (a π - p +a π - n )/2=[-12±2(statistical)±8(systematic)]x10 -4 m π -1 and (a π - p -a π - n )/2=[895±3(statistical)±13 (systematic)]x10 -4 m π -1 . For the need of the present analysis, we improve the theoretical description of the pion-deuteron scattering length
Mass and scattering length inequalities in QCD and QCD-like theories
International Nuclear Information System (INIS)
Nussinov, S.; Pennsylvania Univ., Philadelphia; Sathiapalan, B.
1985-01-01
Some observations about mass scattering length inequalities in QCD-like theories are presented. It is shown that the Weingarten mass inequality can be used to argue that global vector symmetries are unbroken in such theories. For QCD, in the limit Nsub(c)->infinite, it is shown that Msub(baryon)>=1/2Nsub(c)Msub(meson), provided there are at least Nsub(c) degenerate flavors of quarks. It is argued that when there are not bound states in a scattering channel, the mass inequalities can be used to derive inequalities beteen scattering lengths. Some rigorous inequalities for two and higher point functions for operators bilinear in currents are derived, and used to extract inequalities between quartic coupling constants. (orig.)
A rigorous phenomenological analysis of the ππ scattering lengths
International Nuclear Information System (INIS)
Caprini, I.; Dita, P.; Sararu, M.
1979-11-01
The constraining power of the present experimental data, combined with the general theoretical knowledge about ππ scattering, upon the scattering lengths of this process, is investigated by means of a rigorous functional method. We take as input the experimental phase shifts and make no hypotheses about the high energy behaviour of the amplitudes, using only absolute bounds derived from axiomatic field theory and exact consequences of crossing symmetry. In the simplest application of the method, involving only the π 0 π 0 S-wave, we explored numerically a number of values proposed by various authors for the scattering lengths a 0 and a 2 and found that no one appears to be especially favoured. (author)
Spin-dependent transport in cobalt nanocontacts
Energy Technology Data Exchange (ETDEWEB)
Sarau, G.
2007-04-16
The magnetoresistance response of cobalt nanocontacts with varying geometries formed between two extended electrodes has been experimentally investigated and linked to micromagnetic simulations. The contribution of the nanoconstriction to the measured magnetoresistance signal has been separated from that of the electrode bulk. The different nanocontact geometries exhibit different shape anisotropies resulting in a characteristic behavior of the magnetization at each nanocontact. The magnetization reversal processes are explained on the basis of the anisotropic magnetoresistance and domain wall scattering effects. The domain wall resistance takes positive values, which is in agreement with models based on the spin mistracking inside the domain wall. The 4 K MR measurements are found to be influenced by the exchange bias effect between the ferromagnetic cobalt electrodes and the antiferromagnetic oxidized Co surface. When cooling down in an applied magnetic field, the uniform biased Co layer behaves as if it possesses a unidirectional anisotropy axis along the field cooling direction. In the zero field cooling case, the exchange bias varies locally throughout the sample giving rise to non-reproducible successive MR traces. (orig.)
Isotope effects in complex scattering lengths for He collisions with molecular hydrogen
International Nuclear Information System (INIS)
Nolte, J. L.; Yang, B. H.; Stancil, P. C.; Lee, Teck-Ghee; Balakrishnan, N.; Forrey, R. C.; Dalgarno, A.
2010-01-01
We examine the effect of theoretically varying the collision-system reduced mass in collisions of He with vibrationally excited molecular hydrogen and observe zero-energy resonances for select atomic 'hydrogen' masses less than 1 u or a 'helium' mass of 1.95 u. Complex scattering lengths, state-to-state vibrational quenching cross sections, and a low-energy elastic scattering resonance are all studied as a function of collision-system reduced mass. Experimental observations of these phenomena in the cold and ultracold regimes for collisions of 3 He and 4 He with H 2 , HD, HT, and DT should be feasible in the near future.
Ab initio study of spin-dependent transport in carbon nanotubes with iron and vanadium adatoms
DEFF Research Database (Denmark)
Fürst, Joachim Alexander; Brandbyge, Mads; Jauho, Antti-Pekka
2008-01-01
(majority or minority) being scattered depends on the adsorbate and is explained in terms of d-state filling. We contrast the single-walled carbon nanotube results to the simpler case of the adsorbate on a flat graphene sheet with periodic boundary conditions and corresponding width in the zigzag direction......We present an ab initio study of spin-dependent transport in armchair carbon nanotubes with transition metal adsorbates: iron or vanadium. The method based on density functional theory and nonequilibrium Green's functions is used to compute the electronic structure and zero-bias conductance...
Influence of soliton distributions on the spin-dependent electronic ...
Indian Academy of Sciences (India)
Based on Su–Schrieffer–Heeger (SSH) Hamiltonian and using a generalized Green's function formalism, wecalculate the spin-dependent currents, the electronic transmission and tunnelling magnetoresistance (TMR). We found that the presence of a uniform distribution of the soliton centres along the molecular chain ...
Magnetic corrections to π -π scattering lengths in the linear sigma model
Loewe, M.; Monje, L.; Zamora, R.
2018-03-01
In this article, we consider the magnetic corrections to π -π scattering lengths in the frame of the linear sigma model. For this, we consider all the one-loop corrections in the s , t , and u channels, associated to the insertion of a Schwinger propagator for charged pions, working in the region of small values of the magnetic field. Our calculation relies on an appropriate expansion for the propagator. It turns out that the leading scattering length, l =0 in the S channel, increases for an increasing value of the magnetic field, in the isospin I =2 case, whereas the opposite effect is found for the I =0 case. The isospin symmetry is valid because the insertion of the magnetic field occurs through the absolute value of the electric charges. The channel I =1 does not receive any corrections. These results, for the channels I =0 and I =2 , are opposite with respect to the thermal corrections found previously in the literature.
Ericson, Torleif Eric Oskar; Thomas, A W
2000-01-01
We critically evaluate the isovector GMO sumrule for the charged $\\pi N N$ coupling constant using recent precision data from $\\pi ^-$p and $\\pi^-$d atoms and with careful attention to systematic errors. From the $\\pi ^-$d scattering length we deduce the pion-proton scattering lengths ${1/2}(a_{\\pi ^-p}+a_{\\pi ^-n})=(-20\\pm 6$(statistic)$ \\pm 10$ (systematic))~$\\cdot 10^{-4}m_{\\pi_c}^{-1}$ and ${1/2}(a_{\\pi ^-p}-a_{\\pi ^-n})=(903 \\pm 14)\\cdot 10^{-4}m_{\\pi_c}^{-1}$. From this a direct evaluation gives $g^2_c(GMO) =14.20\\pm 0.07$(statistic)$\\pm 0.13$(systematic) or $f^2_c= 0.0786\\pm 0.0008$.
A phenomenological {pi}{sup -}p scattering length from pionic hydrogen
Energy Technology Data Exchange (ETDEWEB)
Ericson, T.E.O.; Loiseau, B.; Wycech, S
2004-07-29
We derive a closed, model independent, expression for the electromagnetic correction factor to a phenomenological hadronic scattering length a{sup h} extracted from a hydrogenic atom. It is obtained in a non-relativistic approach and in the limit of a short ranged hadronic interaction to terms of order {alpha}{sup 2}log{alpha} using an extended charge distribution. A hadronic {pi}N scattering length a{sup h}{sub {pi}{sup -}}{sub p}=0.0870(5)m{sub {pi}}{sup -1} is deduced leading to a {pi}NN coupling constant from the GMO relation g{sub c}{sup 2}/(4{pi})=14.04(17)
The {pi}{sup +}{pi}{sup +} scattering length from maximally twisted mass lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Feng, Xu [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Jansen, Karl; Renner, Dru [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2009-12-15
We calculate the s-wave pion-pion scattering length in the isospin I=2 channel in lattice QCD for pion masses ranging from 270 Mev to 485 Mev using two flavors of maximally twisted mass fermions at a lattice spacing of 0.086 fm. Additionally, we check for lattice artifacts with one calculation at a finer lattice spacing of 0.067 fm. We use chiral perturbation theory at next-to-leading order to extrapolate our results. At the physical pion mass, we find m{sub {pi}}a{sup I=2}{sub {pi}}{sub {pi}}=-0.04385(28)(38) for the scattering length, where the first error is statistical and the second is our estimate of several systematic effects. (orig.)
Theory of spin-dependent tunnelling in magnetic junctions
International Nuclear Information System (INIS)
Mathon, J.
2002-01-01
Rigorous theory of the tunnelling magnetoresistance (TMR) based on the real-space Kubo formula and fully realistic tight-binding bands fitted to an ab initio band structure is described. It is first applied to calculate the TMR of two Co electrodes separated by a vacuum gap. The calculated TMR ratio reaches ∼65% in the tunnelling regime but can be as high as 280% in the metallic regime when the vacuum gap is of the order of the Co interatomic distance (abrupt domain wall). It is also shown that the spin polarization P of the tunnelling current is negative in the metallic regime but becomes positive P∼35% in the tunnelling regime. Calculation of the TMR of an epitaxial Fe/MgO/Fe(001) junction is also described. The calculated optimistic TMR ratio is in excess of 1000% for an MgO barrier of ∼20 atomic planes and the spin polarization of the tunnelling current is positive for all MgO thicknesses. It is also found that spin-dependent tunnelling in an Fe/MgO/Fe(001) junction is not entirely determined by states at the Γ point (k parallel = 0) even for MgO thicknesses as large as ∼20 atomic planes. Finally, it is demonstrated that the TMR ratio calculated from the Kubo formula remains non-zero when one of the Co electrodes is covered with a copper layer. It is shown that non-zero TMR is due to quantum well states in the Cu layer which do not participate in transport. Since these only occur in the down-spin channel, their loss from transport creates a spin asymmetry of electrons tunnelling from a Cu interlayer, i.e. non-zero TMR. Numerical modelling is used to show that diffuse scattering from a random distribution of impurities in the barrier may cause quantum well states to evolve into propagating states, in which case the spin asymmetry of the non-magnetic layer is lost and with it the TMR. (author)
Trotter, D. E. Gonzalez; Salinas, F.; Chen, Q.; Crowell, A. S.; Gloeckle, W.; Howell, C. R.; Roper, C. D.; Schmidt, D.; Slaus, I.; Tang, H.; Tornow, W.; Walter, R. L.; Witala, H.; Zhou, Z.
1999-01-01
The present paper reports high-accuracy cross-section data for the 2H(n,nnp) reaction in the neutron-proton (np) and neutron-neutron (nn) final-state-interaction (FSI) regions at an incident mean neutron energy of 13.0 MeV. These data were analyzed with rigorous three-nucleon calculations to determine the 1S0 np and nn scattering lengths, a_np and a_nn. Our results are a_nn = -18.7 +/- 0.6 fm and a_np = -23.5 +/- 0.8 fm. Since our value for a_np obtained from neutron-deuteron (nd) breakup agr...
Determination of ππ scattering lengths from measurement of π+π- atom lifetime
International Nuclear Information System (INIS)
Adeva, B.; Afanasyev, L.; Benayoun, M.; Benelli, A.; Berka, Z.; Brekhovskikh, V.; Caragheorgheopol, G.; Cechak, T.; Chiba, M.; Chliapnikov, P.V.; Ciocarlan, C.; Constantinescu, S.; Costantini, S.; Curceanu, C.; Doskarova, P.; Dreossi, D.; Drijard, D.; Dudarev, A.; Ferro-Luzzi, M.; Fungueirino Pazos, J.L.
2011-01-01
The DIRAC experiment at CERN has achieved a sizeable production of π + π - atoms and has significantly improved the precision on its lifetime determination. From a sample of 21 227 atomic pairs, a 4% measurement of the S-wave ππ scattering length difference |a 0 -a 2 |=(0.2533 -0.0078 +0.0080 | stat +0.0078 -0.0073 | syst )M π + -1 has been attained, providing an important test of Chiral Perturbation Theory.
Determination of the pion-nucleon coupling constant and scattering lengths
Ericson, Torleif Eric Oskar; Thomas, A W
2002-01-01
We critically evaluate the isovector GMO sum rule for forward pion-nucleon scattering using the recent precision measurements of negatively charged pion-proton and pion-deuteron scattering lengths from pionic atoms. We deduce the charged-pion-nucleon coupling constant, with careful attention to systematic and statistical uncertainties. This determination gives, directly from data a pseudoscalar coupling constant of 14.17+-0.05(statistical)+-0.19(systematic) or a pseudovector one of 0.0786(11). This value is intermediate between that of indirect methods and the direct determination from backward neutron-proton differential scattering cross sections. We also use the pionic atom data to deduce the coherent symmetric and antisymmetric sums of the negatively charged pion-proton and pion-neutron scattering lengths with high precision. The symmetric sum gives 0.0017+-0.0002(statistical)+-0.0008 (systematic) and the antisymmetric one 0.0900+-0.0003(statistical)+-0.0013(systematic), both in units of inverse charged pi...
Generalized spin-dependent WIMP-nucleus interactions and the DAMA modulation effect
Energy Technology Data Exchange (ETDEWEB)
Scopel, Stefano; Yoon, Kook-Hyun; Yoon, Jong-Hyun, E-mail: scopel@sogang.ac.kr, E-mail: koreasds@naver.com, E-mail: pledge200@gmail.com [Department of Physics, Sogang University, Seoul (Korea, Republic of)
2015-07-01
Guided by non-relativistic Effective Field Theory (EFT) we classify the most general spin-dependent interactions between a fermionic Weakly Interacting Massive Particle (WIMP) and nuclei, and within this class of models we discuss the viability of an interpretation of the DAMA modulation result in terms of a signal from WIMP elastic scatterings using a halo-independent approach. We find that, although several relativistic EFT's can lead to a spin-dependent cross section, in some cases with an explicit, non-negligible dependence on the WIMP incoming velocity, three main scenarios can be singled out in the non-relativistic limit which approximately encompass them all, and that only differ by their dependence on the transferred momentum. For two of them compatibility between DAMA and other constraints is possible for a WIMP mass below 30 GeV, but only for a WIMP velocity distribution in the halo of our Galaxy which departs from a Maxwellian. This is achieved by combining a suppression of the WIMP effective coupling to neutrons (to evade constraints from xenon and germanium detectors) to an explicit quadratic or quartic dependence of the cross section on the transferred momentum (that leads to a relative enhancement of the expected rate off sodium in DAMA compared to that off fluorine in droplet detectors and bubble chambers). For larger WIMP masses the same scenarios are excluded by scatterings off iodine in COUPP.
Direct observation of the spin-dependent Peltier effect.
Flipse, J; Bakker, F L; Slachter, A; Dejene, F K; van Wees, B J
2012-02-05
The Peltier coefficient describes the amount of heat that is carried by an electrical current when it passes through a material. When two materials with different Peltier coefficients are placed in contact with one another, the Peltier effect causes a net flow of heat either towards or away from the interface between them. Spintronics describes the transport of electric charge and spin angular momentum by separate spin-up and spin-down channels in a device. The observation that spin-up and spin-down charge transport channels are able to transport heat independently of each other has raised the possibility that spin currents could be used to heat or cool the interface between materials with different spin-dependent Peltier coefficients. Here, we report the direct observation of the heating and cooling of such an interface by a spin current. We demonstrate this spin-dependent Peltier effect in a spin-valve pillar structure that consists of two ferromagnetic layers separated by a non-ferromagnetic metal. Using a three-dimensional finite-element model, we extract spin-dependent Peltier coefficients in the range -0.9 to -1.3 mV for permalloy. The magnetic control of heat flow could prove useful for the cooling of nanoscale electronic components or devices.
Radiative kaon capture on deuterium and the Λn scattering lengths
International Nuclear Information System (INIS)
Gall, K.P.; Booth, E.C.; Fickinger, W.J.; Hasinoff, M.D.; Hessey, N.P.; Horvath, D.; Lowe, J.; McIntyre, E.K.; Measday, D.F.; Miller, J.P.; Noble, A.J.; Roberts, B.L.; Robinson, D.K.; Sakitt, M.; Salomon, M.; Whitehouse, D.A.
1990-01-01
The photon spectrum from K - d→Λnγ at rest has been measured for the first time. We obtained the branching ratio, in the end-point region, of (1.89±0.12±0.28)x10 -3 where the first error is statistical and the second is systematic. We have found that the shape of the photon energy spectrum is consistent with the distribution calculated by Workman and Fearing with Λn scattering lengths and effective ranges predicted by the Nijmegen group
Determination of {pi}{pi} scattering lengths from measurement of {pi}{sup +{pi}-} atom lifetime
Energy Technology Data Exchange (ETDEWEB)
Adeva, B. [Santiago de Compostela University (Spain); Afanasyev, L. [JINR Dubna (Russian Federation); Benayoun, M. [LPNHE des Universites Paris VI/VII, IN2P3-CNRS (France); Benelli, A. [Zurich University (Switzerland); Berka, Z. [Czech Technical University in Prague, Prague (Czech Republic); Brekhovskikh, V. [IHEP Protvino (Russian Federation); Caragheorgheopol, G. [IFIN-HH, National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Cechak, T. [Czech Technical University in Prague, Prague (Czech Republic); Chiba, M. [Tokyo Metropolitan University (Japan); Chliapnikov, P.V. [IHEP Protvino (Russian Federation); Ciocarlan, C.; Constantinescu, S. [IFIN-HH, National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Costantini, S. [Basel University (Switzerland); Curceanu, C. [IFIN-HH, National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Doskarova, P. [Czech Technical University in Prague, Prague (Czech Republic); Dreossi, D. [INFN, Sezione di Trieste and Trieste University, Trieste (Italy); Drijard, D., E-mail: Daniel.Drijard@cern.ch [CERN, Geneva (Switzerland); Dudarev, A. [JINR Dubna (Russian Federation); Ferro-Luzzi, M. [CERN, Geneva (Switzerland); Fungueirino Pazos, J.L. [Santiago de Compostela University (Spain)
2011-10-05
The DIRAC experiment at CERN has achieved a sizeable production of {pi}{sup +{pi}-} atoms and has significantly improved the precision on its lifetime determination. From a sample of 21 227 atomic pairs, a 4% measurement of the S-wave {pi}{pi} scattering length difference |a{sub 0}-a{sub 2}|=(0.2533{sub -0.0078}{sup +0.0080}|{sub stat}{sup +0.0078}{sub -0.0073}|{sub syst})M{sub {pi}}{sup +-1} has been attained, providing an important test of Chiral Perturbation Theory.
Scattering length measurements from radiative pion capture and neutron-deuteron breakup
International Nuclear Information System (INIS)
Gibson, B.F.; Tornow, W.; Carman, T.S.
1997-07-01
The neutron-neutron and neutron-proton 1 S 0 scattering lengths a nn and a np , respectively, were determined simultaneously from the neutron-deuteron breakup reaction. Their comparison with the recommended values obtained from two body reactions gives a measure of the importance of three-nucleon force effects in the three-nucleon continuum. In order to check on the result obtained for a nn from the two-body π - -d capture reaction, a new measurement was performed at LANL. Preliminary results of the three experiments are given
Electromagnetic effects and scattering lengths extraction from experimental data on K → 3π decays
International Nuclear Information System (INIS)
Gevorkyan, S.R.; Madigozhin, D.T.; Tarasov, A.V.; Voskresenskaya, O.O.
2008-01-01
The final state interactions in K ± → π ± π 0 π 0 decays are considered using the methods of non-relativistic quantum mechanics. We show how to take into account the largest electromagnetic effect in the analysis of experimental data using the amplitudes calculated earlier. We propose the relevant expressions for amplitude corrections valid both above and below the two charged pion production threshold M π 0 π 0 2m π ± , including the average effect for the threshold bin. These formulae can be used in the procedure of pion scattering lengths measurement from M π 0 π 0 spectrum
Experimental determination of anomalous scattering lengths of samarium for thermal neutrons
International Nuclear Information System (INIS)
Engel, D.W.; Koetzle, T.F.
1981-01-01
Anomalous scattering lengths of natural Sm for thermal neutrons with wavelengths between 0.827 and 1.300 A have been determined using a single crysrtal of a Sm-complex of known structure. 140 selected reflections were measured at each wavelength and b 0 + b' and b'' refined in each case. The values obtained are in good agreement with theoretical values obtained from a Breit-Wigner calculation using tabulated resonance parameters for 149 Sm. A value of b 0 = 4.3 +- 0.2 fm is deduced from the diffraction experiment
Laser scattering in large-scale-length plasmas relevant to National Ignition Facility hohlraums
International Nuclear Information System (INIS)
MacGowan, B.J.; Berger, R.L.; Afeyan, B.B.
1996-10-01
We have used homogeneous plasmas of high density (up to 1.3 X 10 21 electrons per cm 3 ) and temperature (∼ 3 keV) with large density scale lengths (∼2 mm) to approximate conditions within National Ignition Facility (NIF) hohlraums. Within these plasmas we have studied the dependence of stimulated Raman (SRS) and Brillouin (SBS) scattering on beam smoothing and plasma conditions at the relevant laser intensity (3ω, 2 X 10 15 Wcm 2 ). Both SBS and SRS are reduced by the use of smoothing by spectral dispersion (SSD)
Scattering length measurements from radiative pion capture and neutron-deuteron breakup
Energy Technology Data Exchange (ETDEWEB)
Tornow, W.; Chen, Q. [Duke Univ., Durham, NC (United States). Dept. of Physics; Carman, T.S. [Lawrence Livermore National Lab., CA (United States). Program for Climate Model Diagnosis and Intercomparison] [and others
1998-03-02
The neutron-neutron and neutron-proton {sup 1}S{sub 0} scattering lengths a{sub nn} and a{sub np}, respectively, were determined simultaneously from the neutron-deuteron breakup reaction. Their comparison with the recommended values obtained from ``two-body`` reactions gives a measure of the importance of three-nucleon force effects in the three-nucleon continuum. In order to check on the result obtained for a{sub nn} from the ``two-body`` {pi}{sup -}-d capture reaction, a new measurement was performed at LANL. Preliminary results of the three experiments are given. (orig.). 5 refs.
International Nuclear Information System (INIS)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner
2012-01-01
The following topics are dealt with: Neutron scattering in contemporary research, neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)
Exotic Paired States with Anisotropic Spin-Dependent Fermi Surfaces
International Nuclear Information System (INIS)
Feiguin, Adrian E.; Fisher, Matthew P. A.
2009-01-01
We propose a model for realizing exotic paired states in cold Fermi gases by using a spin-dependent optical lattice to engineer mismatched Fermi surfaces for each hyperfine species. The BCS phase diagram shows a stable paired superfluid state with coexisting pockets of momentum space with gapless unpaired carriers, similar to the Sarma state in polarized mixtures, but in our case the system is unpolarized. We propose the possible existence of an exotic 'Cooper-pair Bose-metal' phase, which has a gap for single fermion excitations but gapless and uncondensed 'Cooper-pair' excitations residing on a 'Bose surface' in momentum space.
Influence of core diameter and length of polymer optical fiber on Brillouin scattering properties
Mizuno, Yosuke; Ishigure, Takaaki; Nakamura, Kentaro
2012-02-01
Brillouin scattering in perfluorinated graded-index polymer optical fibers (PFGI-POFs) is potentially useful in developing high-accuracy distributed temperature sensors with reduced strain sensitivity. In this study, we investigate, both experimentally and theoretically, the influence of the fiber core diameter and length on the Brillouin gain spectra (BGS) in PFGI-POFs. First, we show that smaller core diameter drastically enhances the Stokes power using PFGI-POFs with 62.5-μm and 120-μm core diameters, and discuss the Brillouin threshold power. Then, we demonstrate that the PFGI-POF length has little influence on the BGS when the length is longer than 50 m. We also predict that, at 1.55-μm wavelength, it is difficult to reduce the Brillouin threshold power of PFGI-POFs below that of long silica single-mode fibers even if their core diameter is sufficiently reduced to satisfy the single-mode condition. Finally, making use of the enhanced Stokes signal, we confirm the Brillouin linewidth narrowing effect.
Soliton scatterings by impurities in a short-length sine-Gordon chain
International Nuclear Information System (INIS)
Dikande, A.M.; Kofane, T.C.
1995-07-01
The scattering of soliton by impurities at the frontiers of a finite-length region of an infinite sine-Gordon chain is analyzed. The impurities consist of two isotopic inhomogeneities installed at the boundaries of the finite-length region. The soliton solution in the region is found in term of snoidal sine-Gordon soliton which properly takes into account the effects of the boundaries. By contrast, the soliton solutions in the neighboring sides of the region are obtained in terms of the so-called large-amplitude, localized kinks with limiting spatial extensions at x → ± ∞, which is equal ±π. Using the continuity of these soliton solutions at the frontiers as well as appropriate boundary conditions, it is shown that the soliton may be either i) reflected by the incident impurity; ii) trapped (with oscillating motions) between the two impurities (i.e. inside the infinite region); or iii) transmitted by the second impurity into the third, infinitely extended region. The threshold velocities for the reflection and transmission into different regions are found and shown to vary exponentially as a function of the length of the bounded region. The frequency of soliton oscillations between the impurities has also been calculated in some acceptable limit. (author). 28 refs, 1 fig
The magnetism and spin-dependent electronic transport properties of boron nitride atomic chains
International Nuclear Information System (INIS)
An, Yipeng; Zhang, Mengjun; Wang, Tianxing; Jiao, Zhaoyong; Wu, Dapeng; Fu, Zhaoming; Wang, Kun
2016-01-01
Very recently, boron nitride atomic chains were successively prepared and observed in experiments [O. Cretu et al., ACS Nano 8, 11950 (2015)]. Herein, using a first-principles technique, we study the magnetism and spin-dependent electronic transport properties of three types of BN atomic chains whose magnetic moment is 1 μ B for B n N n−1 , 2 μ B for B n N n , and 3 μ B for B n N n+1 type atomic chains, respectively. The spin-dependent electronic transport results demonstrate that the short B n N n+1 chain presents an obvious spin-filtering effect with high spin polarization ratio (>90%) under low bias voltages. Yet, this spin-filtering effect does not occur for long B n N n+1 chains under high bias voltages and other types of BN atomic chains (B n N n−1 and B n N n ). The proposed short B n N n+1 chain is predicted to be an effective low-bias spin filters. Moreover, the length-conductance relationships of these BN atomic chains were also studied.
Spin-dependent Peltier effect in 3D topological insulators
Sengupta, Parijat; Kubis, Tillmann; Povolotskyi, Michael; Klimeck, Gerhard
2013-03-01
The Peltier effect represents the heat carrying capacity of a certain material when current passes through it. When two materials with different Peltier coefficients are placed together, the Peltier effect causes heat to flow either towards or away from the interface between them. This work utilizes the spin-polarized property of 3D topological insulator (TI) surface states to describe the transport of heat through the spin-up and spin-down channels. It has been observed that the spin channels are able to carry heat independently of each other. Spin currents can therefore be employed to supply or extract heat from an interface between materials with spin-dependent Peltier coefficients. The device is composed of a thin film of Bi2Se3 sandwiched between two layers of Bi2Te3. The thin film of Bi2Se3serves both as a normal and topological insulator. It is a normal insulator when its surfaces overlap to produce a finite band-gap. Using an external gate, Bi2Se3 film can be again tuned in to a TI. Sufficiently thick Bi2Te3 always retain TI behavior. Spin-dependent Peltier coefficients are obtained and the spin Nernst effect in TIs is shown by controlling the temperature gradient to convert charge current to spin current.
Spin-dependent tunneling transport in a lateral magnetic diode
International Nuclear Information System (INIS)
Wang, Yu; Shi, Ying
2012-01-01
Based on the gate-tunable two-dimensional electron gas, we have constructed laterally a double-barrier resonant tunneling structure by employing a peculiar triple-gate configuration, namely a ferromagnetic gate sandwiched closely by a pair of Schottky gates. Because of the in-plane stray field of ferromagnetic gate, the resulting bound spin state in well gives rise to the remarkable resonant spin polarization following the spin-dependent resonant tunneling regime. Importantly, by aligning the bound spin state through surface gate-voltage configuration, this resonant spin polarization can be externally manipulated, showing the desirable features for the spin-logic device applications. -- Highlights: ► A lateral spin-RTD was proposed by applying triple-gate modulated 2DEG. ► Spin-dependent resonant tunneling transport and large resonant spin polarization has been clarified from the systematic simulation. ► Both electric and/or magnetic strategies can be employed to modulate the system spin transport, providing the essential features for the spin-logic application.
Recent high-accuracy measurements of the 1S0 neutron-neutron scattering length
International Nuclear Information System (INIS)
Howell, C.R.; Chen, Q.; Gonzalez Trotter, D.E.; Salinas, F.; Crowell, A.S.; Roper, C.D.; Tornow, W.; Walter, R.L.; Carman, T.S.; Hussein, A.; Gibbs, W.R.; Gibson, B.F.; Morris, C.; Obst, A.; Sterbenz, S.; Whitton, M.; Mertens, G.; Moore, C.F.; Whiteley, C.R.; Pasyuk, E.; Slaus, I.; Tang, H.; Zhou, Z.; Gloeckle, W.; Witala, H.
2000-01-01
This paper reports two recent high-accuracy determinations of the 1 S 0 neutron-neutron scattering length, a nn . One was done at the Los Alamos National Laboratory using the π - d capture reaction to produce two neutrons with low relative momentum. The neutron-deuteron (nd) breakup reaction was used in other measurement, which was conducted at the Triangle Universities Nuclear Laboratory. The results from the two determinations were consistent with each other and with previous values obtained using the π - d capture reaction. The value obtained from the nd breakup measurements is a nn = -18.7 ± 0.1 (statistical) ± 0.6 (systematic) fm, and the value from the π - d capture experiment is a nn = -18.50 ± 0.05 ± 0.53 fm. The recommended value is a nn = -18.5 ± 0.3 fm. (author)
Meson-Baryon Scattering Lengths from Mixed-Action Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Will Detmold, William Detmold, Konstantinos Orginos, Aaron Torok, Silas R Beane, Thomas C Luu, Assumpta Parreno, Martin Savage, Andre Walker-Loud
2010-04-01
The $\\pi^+\\Sigma^+$, $\\pi^+\\Xi^0$ , $K^+p$, $K^+n$, and $K^0 \\Xi^0$ scattering lengths are calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks is used to perform the chiral extrapolations. We find no convergence for the kaon-baryon processes in the three-flavor chiral expansion. Using the two-flavor chiral expansion, we find $a_{\\pi^+\\Sigma^+} = ?0.197 ± 0.017$ fm, and $a_{\\pi^+\\Xi^0} = ?0.098 0.017$ fm, where the comprehensive error includes statistical and systematic uncertainties.
Spin-dependent electron emission from metals in the neutralization of He+ ions
International Nuclear Information System (INIS)
Alducin, M.; Roesler, M.; Juaristi, J.I.; Muino, R. Diez; Echenique, P.M.
2005-01-01
We calculate the spin-polarization of electrons emitted in the neutralization of He + ions interacting with metals. All stages of the emission process are included: the spin-dependent perturbation induced by the projectile, the excitation of electrons in Auger neutralization processes, the creation of a cascade of secondaries, and the escape of the electrons through the surface potential barrier. The model allows us to explain in quantitative terms the measured spin-polarization of the yield in the interaction of spin-polarized He + ions with paramagnetic surfaces, and to disentangle the role played by each of the involved mechanisms. We show that electron-electron scattering processes at the surface determine the spin-polarization of the total yield. High energy emitted electrons are the ones providing direct information on the He + ion neutralization process and on the electronic properties of the surface
The spin-dependent structure function g1 of the deuteron
International Nuclear Information System (INIS)
Bueltmann, S.
1996-01-01
Results on the spin-dependent structure function g 1 d of the deuteron measured by the Spin Muon Collaboration at CERN are presented. They are based on deep-inelastic scattering of 190 GeV polarized muons off a polarized deuteron target in the kinematic range of 0.003 ≤ x Bj ≤ 0.7 and 1 GeV 2 ≤ Q 2 ≤ 60 GeV 2 . The structure function is found to be negative for small values of x Bj , while the proton structure function g 1 p measured earlier by the SMC is positive over the whole x Bj -range. The Bjorken sum rule is in good agreement with the first moments of the structure functions, while the Ellis-Jaffe sum rule is violated by more than three standard deviations for the deuteron measurement. (author)
Recent SLAC measurements of the spin dependent structure functions for the proton and neutron
International Nuclear Information System (INIS)
Zapalac, G.
1995-09-01
The authors present results from SLAC experiments E142 and E143 for the spin dependent structure functions of the proton g 1 p (x, Q 2 ) and neutron g 1 n (x,Q 2 ) measured in deep inelastic scattering of polarized electrons from a polarized target. Experiment E142 measures ∫ 0 1 g 1 n (x)dx = -0.022 ± 0.011 at 2 > = 2 (GeV/c) 2 using a polarized 3 He target. Experiment E143 measures ∫ 0 1 g 1 p (x)dx = 0.129 ± 0.011 at 2 > = 3 (GeV/c) 2 using a polarized NH 3 target. These results are combined at Q 2 = 3 (GeV/c) 2 to yield ∫ 0 1 [g 1 p (x) - g 1 n (x)]dx = 0.151 ± 0.015. The Bjorken sum rule predicts 0.171 ± 0.008
The Deuteron Spin-dependent Structure Function $g^{d}_1$ and its First Moment
Alexakhin, V.Yu.; Alexeev, G.D.; Alexeev, M.; Amoroso, A.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Becker, M.; Bedfer, Y.; Bernet, C.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; De Masi, R.; Dedek, N.; Demchenko, D.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Dinkelbach, A.M.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Duic, V.; Dunnweber, W.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; M. Finger jr.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.A.; Grasso, A.; Grube, B.; Guskov, A.; Haas, F.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Horn, I.; Ilgner, C.; Ioukaev, A.I.; Ivanchin, I.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kouznetsov, O.; Kowalik, K.; Kramer, D.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kubart, J.; Kuhn, R.; Kukhtin, V.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lednev, A.A.; Lehmann, A.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Masek, L.; Massmann, F.; Matsuda, T.; Matthia, D.; Maximov, A.N.; Meyer, W.; Mielech, A.; Mikhailov, Yu. V.; Moinester, M.A.; Nagel, T.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nikolaev, K.; Nozdrin, A.A.; Obraztsov, V.F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Popov, A.A.; Pretz, J.; Procureur, S.; Quintans, C.; Ramos, S.; Reicherz, G.; Rondio, E.; Rozhdestvensky, A.M.; Ryabchikov, D.; Samoylenko, V.D.; Sandacz, A.; Santos, H.; Sapozhnikov, M.G.; Savin, I.A.; Schiavon, P.; Schill, C.; Schmitt, L.; Schroeder, W.; Seeharsch, D.; Seimetz, M.; Setter, D.; Shevchenko, O.Yu.; Siebert, H.W.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sozzi, F.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sugonyaev, V.P.; Sulc, M.; Sulej, R.; Tchalishev, V.V.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Trippel, S.; Venugopal, G.; Virius, M.; Vlassov, N.V.; Webb, R.; Weise, E.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Zhao, J.; Zvyagin, A.
2007-01-01
We present a measurement of the deuteron spin-dependent structure function g^d_1 based on the data collected by the COMPASS experiment at CERN during the years 2002-2004. The data provide an accurate evaluation for \\Gamma^d_1, the first moment of g^d_1(x), and for the matrix element of the singlet axial current, a_0. The results of QCD fits in the next to leading order (NLO) on all g1 deep inelastic scattering data are also presented. They provide two solutions with the gluon spin distribution function \\Delta_G positive or negative, which describe the data equally well. In both cases, at Q^2 = 3(GeV/c)^2 the first moment of \\Delta G is found to be of the order of 0:2 - 0:3 in absolute value.
Coulomb corrections to nuclear scattering lengths and effective ranges for weakly bound systems
International Nuclear Information System (INIS)
Mur, V.D.; Popov, V.S.; Sergeev, A.V.
1996-01-01
A procedure is considered for extracting the purely nuclear scattering length as and effective range rs (which correspond to a strong-interaction potential Vs with disregarded Coulomb interaction) from the experimentally determined nuclear quantities acs and rcs, which are modified by Coulomb interaction. The Coulomb renormalization of as and rs is especially strong if the system under study involves a level with energy close to zero (on the nuclear scale). This applies to formulas that determine the Coulomb renormalization of the low-energy parameters of s scattering (l=0). Detailed numerical calculations are performed for coefficients appearing in the equations that determine Coulomb corrections for various models of the potential Vs(r). This makes it possible to draw qualitative conclusions that the dependence of Coulomb corrections on the form of the strong-interaction potential and, in particular, on its small-distance behavior. A considerable enhancement of Coulomb corrections to the effective range rs is found for potentials with a barrier
Langmack, Christian; Schmidt, Richard; Zwerger, Wilhelm
2018-03-01
We calculate the spectrum of three-body Efimov bound states near a Feshbach resonance within a model which accounts both for the finite range of interactions and the presence of background scattering. The latter may be due to direct interactions in an open channel or a second overlapping Feshbach resonance. It is found that background scattering gives rise to substantial changes in the trimer spectrum as a function of the detuning away from a Feshbach resonance, in particular in the regime where the background channel supports Efimov states on its own. Compared to the situation with negligible background scattering, the regime where van der Waals universality applies is shifted to larger values of the resonance strength if the background scattering length is positive. For negative background scattering lengths, in turn, van der Waals universality extends to even small values of the resonance strength parameter, consistent with experimental results on Efimov states in 39K. Within a simple model, we show that short-range three-body forces do not affect van der Waals universality significantly. Repulsive three-body forces may, however, explain the observed variation between around -8 and -10 of the ratio between the scattering length where the first Efimov trimer appears and the van der Waals length.
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner [eds.
2010-07-01
The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)
International Nuclear Information System (INIS)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner
2013-01-01
The following topics are dealt with: Neutron sources, symmetry of crystals, nanostructures investigated by small-angle neutron scattering, structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic neutron scattering, strongly correlated electrons, polymer dynamics, applications of neutron scattering. (HSI)
International Nuclear Information System (INIS)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner
2010-01-01
The following topics are dealt with: Neutron sources, symmetry of crystals, diffraction, nanostructures investigated by small-angle neutron scattering, the structure of macromolecules, spin dependent and magnetic scattering, structural analysis, neutron reflectometry, magnetic nanostructures, inelastic scattering, strongly correlated electrons, dynamics of macromolecules, applications of neutron scattering. (HSI)
Theoretical models of the spin-dependent charge-carrier dynamics in metals and semiconductors
International Nuclear Information System (INIS)
Krauss, Michael
2010-01-01
-spots'', which are an important characteristic of the spin-orbit interaction in the hole system. Based on the results for holes in GaAs, we have introduced a model for the laser-induced ultrafast demagnetization in the ferromagnetic transition metals cobalt and nickel. Our approach is based on an Elliott-Yafet-type mechanism, i.e., it describes spin-dependent dynamics due to (mainly electron-electron) scattering transitions between states including the spin-orbit interaction. By incorporating details of the optical excitation and scattering mechanisms as well as a sufficiently realistic single-particle band structure we obtain a good agreement with experimental results for the magnitude and time scale of the demagnetization in cobalt and nickel. The last part of this thesis is concerned with an attempt to include correlations of a magnetic type and to go beyond the scattering dynamics in single-particle band structures. We investigate model systems with parameters typical of ferromagnetic semiconductors. We examine correlated spin dynamics in a one-dimensional Kondo-lattice system, and explore the ground state properties by computing the relevant two-particle correlation functions starting from an uncorrelated initial state. (orig.)
Monte Carlo determination of the spin-dependent potentials
International Nuclear Information System (INIS)
Campostrini, M.; Moriarty, K.J.M.; Rebbi, C.
1987-05-01
Calculation of the bound states of heavy quark systems by a Hamiltonian formulation based on an expansion of the interaction into inverse powers of the quark mass is discussed. The potentials for the spin-orbit and spin-spin coupling between quark and antiquark, which are responsible for the fine and hyperfine splittings in heavy quark spectroscopy, are expressed as expectation values of Wilson loop factors with suitable insertions of chromomagnetic or chromoelectric fields. A Monte Carlo simulation has been used to evaluate the expectation values and, from them, the spin-dependent potentials. The Monte Carlo calculation is reported to show a long-range, non-perturbative component in the interaction
Spin-dependent transport through interacting graphene armchair nanoribbons
International Nuclear Information System (INIS)
Koller, Sonja; Mayrhofer, Leonhard; Grifoni, Milena
2010-01-01
We investigate spin effects in transport across fully interacting, finite-size graphene armchair nanoribbons (ACNs) contacted to collinearly spin-polarized leads. In such systems, the presence of short-range Coulomb interaction between bulk states and states localized at the ribbon ends leads to novel spin-dependent phenomena. Specifically, the total spin of the low-energy many-body states is conserved during tunneling but that of the bulk and end states is not. As a consequence, in the single-electron regime, dominated by Coulomb blockade phenomena, we find pronounced negative differential conductance features for ACNs contacted to parallel polarized leads. These features are, however, absent in an anti-parallel contact configuration, which in turn leads, within a certain gate and bias voltage region, to a negative tunneling magneto-resistance. Moreover, we analyze the changes in the transport characteristics under the influence of an external magnetic field.
Spin-dependent quantum transport in nanoscaled geometries
Heremans, Jean J.
2011-10-01
We discuss experiments where the spin degree of freedom leads to quantum interference phenomena in the solid-state. Under spin-orbit interactions (SOI), spin rotation modifies weak-localization to weak anti-localization (WAL). WAL's sensitivity to spin- and phase coherence leads to its use in determining the spin coherence lengths Ls in materials, of importance moreover in spintronics. Using WAL we measure the dependence of Ls on the wire width w in narrow nanolithographic ballistic InSb wires, ballistic InAs wires, and diffusive Bi wires with surface states with Rashba-like SOI. In all three systems we find that Ls increases with decreasing w. While theory predicts the increase for diffusive wires with linear (Rashba) SOI, we experimentally conclude that the increase in Ls under dimensional confinement may be more universal, with consequences for various applications. Further, in mesoscopic ring geometries on an InAs/AlGaSb 2D electron system (2DES) we observe both Aharonov-Bohm oscillations due to spatial quantum interference, and Altshuler-Aronov-Spivak oscillations due to time-reversed paths. A transport formalism describing quantum coherent networks including ballistic transport and SOI allows a comparison of spin- and phase coherence lengths extracted for such spatial- and temporal-loop quantum interference phenomena. We further applied WAL to study the magnetic interactions between a 2DES at the surface of InAs and local magnetic moments on the surface from rare earth (RE) ions (Gd3+, Ho3+, and Sm3+). The magnetic spin-flip rate carries information about magnetic interactions. Results indicate that the heavy RE ions increase the SOI scattering rate and the spin-flip rate, the latter indicating magnetic interactions. Moreover Ho3+ on InAs yields a spin-flip rate with an unusual power 1/2 temperature dependence, possibly characteristic of a Kondo system. We acknowledge funding from DOE (DE-FG02-08ER46532).
The pion-nucleon scattering lengths from pionic hydrogen and deuterium
Energy Technology Data Exchange (ETDEWEB)
Schroeder, H.-C.; Badertscher, A.; Goudsmit, P.F.A.; Janousch, M.; Leisi, H.J.; Matsinos, E.; Sigg, D.; Zhao, Z.G. [ETH Zurich, Inst. for Particle Physics, Zurich (Switzerland); Chatellard, D.; Egger, J.P. [Neuchatel Univ. (Switzerland). Inst. de Physique; Gabathuler, K.; Hauser, P.; Simons, L.M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Rusi El Hassani, A.J. [Dept. de Physique, Faculte des Sciences et Technique, Tanger (Morocco)
2001-07-01
This is the final publication of the ETH Zurich-Neuchatel-PSI collaboration on the pionic hydrogen and deuterium precision X-ray experiments. We describe the recent hydrogen 3p-1s measurement, report on the determination of the Doppler effect correction to the transition line width, analyze the deuterium shift measurement and discuss implications of the combined hydrogen and deuterium results. From the pionic hydrogen 3p-1s transition experiments we obtain the strong-interaction energy level shift {epsilon}{sub 1s} = -7.108{+-}0.013 (stat.){+-}0.034 (syst.) eV and the total decay width {gamma}{sub 1s} = 0.868{+-}0.040 (stat.){+-}0.038 (syst.) eV of the 1s state. Taking into account the electromagnetic corrections we find the hadronic {pi}N s-wave scattering amplitude a{sub {pi}{sup -}p{yields}{pi}{sup -}p} = 0.0883{+-}0.0008 m{sub {pi}}{sup -1} for elastic scattering and a{sub {pi}{sup -}p{yields}{pi}{sup 0}n} = -0.128{+-}0.006 m{sub {pi}} {sup -1} for single charge exchange, respectively. We then combine the pionic hydrogen results with the 1s level shift measurement on pionic deuterium and test isospin symmetry of the strong interaction: our data are still compatible with isospin symmetry. The isoscalar and isovector {pi}N scattering lengths (within the framework of isospin symmetry) are found to be b{sub 0} = -0.0001{sup +0.0009}{sub -0.0021} m{sub {pi}}{sup -1} and b{sub 1} = -0.0885{sup +0.0010}{sub -0.0021} m{sub {pi}} {sup -1}, respectively. Using the GMO sum rule, we obtain from b{sub 1} a new value of the {pi}N coupling constant (g{sub {pi}}{sub N} = 13.21{sub -0.05}{sup +0.11}) from which follows the Goldberger-Treiman discrepancy {delta}{sub GT}=0.027{sub -0.008}{sup +0.012}. The new values of b{sub 0} and g{sub {pi}}{sub N} imply an increase of the nucleon sigma term by at least 9 MeV. (orig.)
International Nuclear Information System (INIS)
Correa, J.R.; Chang Yongbin; Ordonez, C.A.
2005-01-01
Collisional scattering is considered within a system of charged particles experiencing binary Coulomb interactions when the scale length for the range of each interaction is not isotropic and is not necessarily equal to the Debye length. For example, one or more dimensions of the system could be smaller than the Debye length. The effect is assessed by evaluating integrals over the impact cross section. Cutoffs on both the impact parameter and the Coulomb interaction potential are employed, and no assumption is made regarding the value of the Coulomb logarithm. Two expressions are found that have a dependence on the cutoff lengths, with one of the expressions being associated with the Coulomb logarithm. Collisional scattering within an electrostatic ion trap is considered by way of example
Extraction of neutron-neutron scattering length from nn coincidence-geometry nd breakup data
Directory of Open Access Journals (Sweden)
E. S. Konobeevski
2011-03-01
Full Text Available We report preliminary results of a kinematically complete experiment on measurement of nd breakup reaction yield at neutron beam RADEX of Institute for Nuclear Research (Moscow, Russia. In the experiment two secondary neutrons are detected in geometry of neutron-neutron final-state interaction. Data are obtained at energy of incident neutrons En = 40 - 60 MeV for various divergence angles of two neutrons ΔΘ = 4, 6, 8º. 1S0 neutron-neutron scattering length ann were determined by comparison of the experimental dependence of reaction yield on the relative energy of two secondary neutrons with results of simulation depending on ann. For En = 40 MeV and ΔΘ = 6º (the highest statistics in the experiment the value ann = -17.9 ± 1.0 fm is obtained. The further improving of accuracy of the experiment and more rigorous theoretical analysis will allow one to remove the existing difference in ann values obtained in different experiments.
ρ, ω, and φ meson-nucleon scattering lengths from QCD sum rules
International Nuclear Information System (INIS)
Koike, Y.
1995-01-01
The QCD sum rule method is applied to derive a formula for the ρ, ω, and φ meson-nucleon spin-isospin--averaged scattering lengths a ρ,ω,φ . We found that the crucial matrix elements are left-angle bar qγ μ D ν q right-angle N (q=ud) (twist-2 nucleon matrix element) for a ρ,ω and m s left-angle bar ss right-angle N for a φ , and obtained a ρ =0.14±0.07 fm, a ω =0.11±0.06 fm, and a φ =0.035±0.020 fm. These small numbers originate from a common factor 1/(m N +m ρ,ω,φ ). Our result suggests a slight increase (<60 MeV for ρ and ω, and <15 MeV for φ) of the effective mass of these vector mesons in nuclear matter (in the dilute nucleon-gas approximation). The origin of the discrepancy with Hatsuda-Lee was clarified
Meson-Baryon Scattering Lengths from Mixed-Action Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Beane, S; Detmold, W; Luu, T; Orginos, K; Parreno, A; Torok, A; Walker-Loud, A
2009-06-30
The {pi}{sup +}{Sigma}{sup +}, {pi}{sup +}{Xi}{sup 0}, K{sup +}p, K{sup +}n, {bar K}{sup 0}{Sigma}{sup +}, and {bar K}{sup 0}{Xi}{sup 0} scattering lengths are calculated in mixed-action Lattice QCD with domain-wall valence quarks on the asqtad-improved coarse MILC configurations at four light-quark masses, and at two light-quark masses on the fine MILC configurations. Heavy Baryon Chiral Perturbation Theory with two and three flavors of light quarks is used to perform the chiral extrapolations. We find no convergence for the kaon-baryon processes in the three-flavor chiral expansion. Using the two-flavor chiral expansion, we find a{sub {pi}{sup +}{Sigma}{sup +}} = -0.197 {+-} 0.017 fm, and a{sub {pi}{sup +}{Xi}{sup 0}} = -0.098 {+-} 0.017 fm, where the comprehensive error includes statistical and systematic uncertainties.
2D Spin-Dependent Diffraction of Electrons From Periodical Chains of Nanomagnets
Directory of Open Access Journals (Sweden)
Teshome Senbeta
2012-03-01
Full Text Available The scattering of the unpolarized beams of electrons by nanomagnets in the vicinity of some scattering angles leads to complete spin polarized electrons. This result is obtained with the help of the perturbation theory. The dipole-dipole interaction between the magnetic moment of the nanomagnet and the magnetic moment of electron is treated as perturbation. This interaction is not spherically symmetric. Rather it depends on the electron spin variables. It in turn results in spinor character of the scattering amplitudes. Due to the smallness of the magnetic interactions, the scattering length of this process is very small to be proved experimentally. To enhance the relevant scattering lengths, we considered the diffraction of unpolarized beams of electrons by linear chains of nanomagnets. By tuning the distance between the scatterers it is possible to obtain the diffraction maximum of the scattered electrons at scattering angles which corresponds to complete spin polarization of electrons. It is shown that the total differential scattering length is proportional to N2 (N is a number of scatterers. Even small number of nanomagnets in the chain helps to obtain experimentally visible enhancement of spin polarization of the scattered electrons.
2D scattering of unpolarized beams of electrons by charged nanomagnets
Energy Technology Data Exchange (ETDEWEB)
Senbeta, Teshome, E-mail: teshearada@yahoo.com [Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia); Mal' nev, V.N., E-mail: vnmalnev@aau.edu.et [Department of Physics, Addis Ababa University, P.O. Box 1176, Addis Ababa (Ethiopia)
2012-07-15
2D spin-dependent scattering of slow unpolarized beams of electrons by charged nanomagnets is analyzed in the Born approximation. The obtained scattering lengths are larger than those from the neutral nanomagnets approximately by one order. It is shown that for particular parameters of the system it is possible to polarize completely the scattered electrons in a narrow range of scattering angles. The most suitable system for realization of these effects is 2D Si electron gas with immersed nanomagnets. - Highlights: Black-Right-Pointing-Pointer We study 2D spin dependent electron scattering by charged nanomagnets. Black-Right-Pointing-Pointer The applicability of the Born approximation to the problem is discussed. Black-Right-Pointing-Pointer Unpolarized incident beams used to obtain completely polarized scattered electrons. Black-Right-Pointing-Pointer The study shows peculiarities of 2D spin dependent scattering enhanced by Coulomb potential. Black-Right-Pointing-Pointer The result obtained can be used as one method of controlling spin currents.
Spin-dependent tunnelling in magnetic tunnel junctions
International Nuclear Information System (INIS)
Tsymbal, Evgeny Y; Mryasov, Oleg N; LeClair, Patrick R
2003-01-01
The phenomenon of electron tunnelling has been known since the advent of quantum mechanics, but continues to enrich our understanding of many fields of physics, as well as creating sub-fields on its own. Spin-dependent tunnelling (SDT) in magnetic tunnel junctions (MTJs) has recently aroused enormous interest and has developed in a vigorous field of research. The large tunnelling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible applications in non-volatile random-access memories and next-generation magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of SDT. In this review article we present an overview of this field of research. We discuss various factors that control the spin polarization and magnetoresistance in MTJs. Starting from early experiments on SDT and their interpretation, we consider thereafter recent experiments and models which highlight the role of the electronic structure of the ferromagnets, the insulating layer, and the ferromagnet/insulator interfaces. We also discuss the role of disorder in the barrier and in the ferromagnetic electrodes and their influence on TMR. (topical review)
Shape Biased Low Power Spin Dependent Tunneling Magnetic Field Sensors
Tondra, Mark; Qian, Zhenghong; Wang, Dexin; Nordman, Cathy; Anderson, John
2001-10-01
Spin Dependent Tunneling (SDT) devices are leading candidates for inclusion in a number of Unattended Ground Sensor applications. Continued progress at NVE has pushed their performance to 1OOs of pT I rt. Hz 1 Hz. However, these sensors were designed to use an applied field from an on-chip coil to create an appropriate magnetic sensing configuration. The power required to generate this field (^100mW) is significantly greater than the power budget (^lmW) for a magnetic sensor in an Unattended Ground Sensor (UGS) application. Consequently, a new approach to creating an ideal sensing environment is required. One approach being used at NVE is "shape biasing." This means that the physical layout of the SDT sensing elements is such that the magnetization of the sensing film is correct even when no biasing field is applied. Sensors have been fabricated using this technique and show reasonable promise for UGS applications. Some performance trade-offs exist. The power is easily tinder 1 MW, but the sensitivity is typically lower by a factor of 10. This talk will discuss some of the design details of these sensors as well as their expected ultimate performance.
The spin dependent structure function g1 of the deuteron and the proton
International Nuclear Information System (INIS)
Klostermann, L.
1995-01-01
This thesis presents a study on the spin structure of the nucleon, via deep inelastic scattering (DIS) of polarised nuons on polarised proton and deuterium targets. The work was done in the Spin Muon Collaboration (SMC) at CERN in Geneva. From the asymmetry in the scattering cross section for nucleon and lepton spins parallel and anti-parallel, one con determine the spin dependent structure function g 1 , which contains information on the quark and gluon spin distribution functions. The interpretation in the frame work of the quark parton model (QPM) of earlier results on g 1 p by the European Muon Collaboration (EMC), gave an indication that only a small fraction of the proton spin, compatible with zero, is carried by the spins of the constituent quarks. The SMC was set up to check this unexpected result with improved accuracy, and to combine measurements of g 1 p and g 1 d to test a fundamental sum rule in quantum chromodynamics (QCD), the Bjorken sum rule. (orig./WL)
Ficek, Filip; Fadeev, Pavel; Flambaum, Victor V.; Jackson Kimball, Derek F.; Kozlov, Mikhail G.; Stadnik, Yevgeny V.; Budker, Dmitry
2018-05-01
Heretofore undiscovered spin-0 or spin-1 bosons can mediate exotic spin-dependent interactions between standard model particles. Here, we carry out the first search for semileptonic spin-dependent interactions between matter and antimatter. We compare theoretical calculations and spectroscopic measurements of the hyperfine structure of antiprotonic helium to constrain exotic spin- and velocity-dependent interactions between electrons and antiprotons.
Electromagnetic pulse-driven spin-dependent currents in semiconductor quantum rings.
Zhu, Zhen-Gang; Berakdar, Jamal
2009-04-08
We investigate the non-equilibrium charge and spin-dependent currents in a quantum ring with a Rashba spin-orbit interaction (SOI) driven by two asymmetric picosecond electromagnetic pulses. The equilibrium persistent charge and persistent spin-dependent currents are investigated as well. It is shown that the dynamical charge and the dynamical spin-dependent currents vary smoothly with a static external magnetic flux and the SOI provides a SU(2) effective flux that changes the phases of the dynamic charge and the dynamic spin-dependent currents. The period of the oscillation of the total charge current with the delay time between the pulses is larger in a quantum ring with a larger radius. The parameters of the pulse fields control to a certain extent the total charge and the total spin-dependent currents. The calculations are applicable to nanometre rings fabricated in heterojunctions of III-V and II-VI semiconductors containing several hundreds of electrons.
Optical modeling of plasma-deposited ZnO films: Electron scattering at different length scales
International Nuclear Information System (INIS)
Knoops, Harm C. M.; Loo, Bas W. H. van de; Smit, Sjoerd; Ponomarev, Mikhail V.; Weber, Jan-Willem; Sharma, Kashish; Kessels, Wilhelmus M. M.; Creatore, Mariadriana
2015-01-01
In this work, an optical modeling study on electron scattering mechanisms in plasma-deposited ZnO layers is presented. Because various applications of ZnO films pose a limit on the electron carrier density due to its effect on the film transmittance, higher electron mobility values are generally preferred instead. Hence, insights into the electron scattering contributions affecting the carrier mobility are required. In optical models, the Drude oscillator is adopted to represent the free-electron contribution and the obtained optical mobility can be then correlated with the macroscopic material properties. However, the influence of scattering phenomena on the optical mobility depends on the considered range of photon energy. For example, the grain-boundary scattering is generally not probed by means of optical measurements and the ionized-impurity scattering contribution decreases toward higher photon energies. To understand this frequency dependence and quantify contributions from different scattering phenomena to the mobility, several case studies were analyzed in this work by means of spectroscopic ellipsometry and Fourier transform infrared (IR) spectroscopy. The obtained electrical parameters were compared to the results inferred by Hall measurements. For intrinsic ZnO (i-ZnO), the in-grain mobility was obtained by fitting reflection data with a normal Drude model in the IR range. For Al-doped ZnO (Al:ZnO), besides a normal Drude fit in the IR range, an Extended Drude fit in the UV-vis range could be used to obtain the in-grain mobility. Scattering mechanisms for a thickness series of Al:ZnO films were discerned using the more intuitive parameter “scattering frequency” instead of the parameter “mobility”. The interaction distance concept was introduced to give a physical interpretation to the frequency dependence of the scattering frequency. This physical interpretation furthermore allows the prediction of which Drude models can be used in a specific
A high-accuracy extraction of the isoscalar πN scattering length from pionic deuterium data
International Nuclear Information System (INIS)
Phillips, Daniel R.; Baru, Vadim; Hanhart, Christoph; Nogga, Andreas; Hoferichter, Martin; Kubis, Bastian
2010-01-01
We present a high-accuracy calculation of the π(bar sign)d scattering length using chiral perturbation theory up to order (M π /m p ) 7/2 . For the first time isospin-violating corrections are included consistently. The resulting value of a π -bar d has a theoretical uncertainty of a few percent. We use it, together with data on pionic deuterium and pionic hydrogen atoms, to extract the isoscalar and isovector pion-nucleon scattering lengths from a combined analysis, and obtain a + (7.9±3.2)·10 -3 M π -1 and a-bar (86.3±1.0)·10 -3 M π -1 .
Precision determination of the πN scattering lengths and the charged πNN coupling constant
International Nuclear Information System (INIS)
Ericson, T.E.O.; Loiseau, B.; Thomas, A.W.
2000-01-01
We critically evaluate the isovector GMO sumrule for the charged πNN coupling constant using recent precision data from π - p and π - d atoms and with careful attention to systematic errors. From the π - d scattering length we deduce the pion-proton scattering lengths ((1)/(2))(a π - p + a π - n ) = (-20 ± 6(statistic)±10 (systematic) ·10 -4 m -1 π c and ((1)/(2))(a π - p - a π - n ) = (903 ± 14) · 10 -4 m -1 π c . From this a direct evaluation gives g 2 c (GMO)/4π = 14.20 ± 0.07 (statistic)±0.13(systematic) or f 2 c /4π = 0.0786 ± 0.0008
International Nuclear Information System (INIS)
Hjelm, R.P.; Wampler, W.; Gerspacher, M.
1994-01-01
As part of our work on the, structure of composite materials we have been exploring the use of small-angle neutron scattering using the method of contrast variation to dissect the component form, structure and distribution. This approach has resulted in a new look at very old problem reinforcement of elastomers by carbon black. Using this approach we studied an experimental high surface area (HSA) carbon black and a gel of ''HSA-bound'' rubber in cyclohexane/deuterocyclohexane mixtures. HSA in cyclohexane is found to be short rodlike particle aggregates. The aggregates have a shell-core structure with a high density graphitic outer shell and an inner core of lower density amorphous carbon. The core is continuous throughout the carbon black aggregate, making the aggregate a stiff, integral unit. Contrast variation of swollen composite gels shows that there are two length scales in the gel structure. Above 10 Angstrom, scattering from carbon black predominates, and below 10 Angstrom the scattering is from both carbon black and the elastomer. The HSA in the composite is completely embedded in polyisoprene. An estimate of the carbon black structure factor shows strong exclusion of neighboring aggregates, probably from excluded volume effects. The surface structure of the carbon black is unaltered by the interactions with elastomer and appears smooth over length scales above about 10 Angstrom. These results show that contrast variation can provide information on composite structure that is not available by other means. This information relates to the reinforcement mechanism of elastomers by carbon blacks
Determination of nn scattering length from data on nn final state interaction in nd-breakup reaction
International Nuclear Information System (INIS)
Konobeevski, E.S.; Mordovskoy, M.V.; Sergeev, V.A.; Potashev, S.I.; Zuev, S.V.
2006-01-01
Full text: An experiment is proposed for the high-precision determination of the neutron-neutron scattering length investigating the nn final state interaction in the nd breakup reaction. The singlet pp and nn scattering lengths are very sensitive probes of the NN-interaction, and their difference is a direct measure of charge-symmetry breaking (CSB) of the nuclear force. However CSB is a small effect, and accurate values of the scattering lengths are needed for a theoretical analysis. The proton-proton scattering length is well known from pp-scattering data (a pp = -17.3± 0.4 fm), and its uncertainty is mainly due to a model-dependent procedure of removing Coulomb effects. The neutron-neutron scattering length is determined from the following processes n+d→p+n+n, π - + d → γ +n+n, d+d→ 2 He+n+n by investigating the kinematic region of the nn final-state interaction (FSI) where two neutrons fly with low relative energy. The results obtained by now are characterized by a significant uncertainty in values of a nn ; they are grouped near -16 and -19 fm [1,2], so even the sign of the difference a nn - a pp is uncertain. In this experiment neutron-neutron scattering length is determined by measuring the yield of the nd breakup reaction as a function of the relative energy ε nn =(E 1 +E 2 -2(E 1 E 2 ) 1/2 cosθ)/2 of two neutrons in the FSI region (two neutrons fly in a narrow angular cone) where nn-interaction is strongly revealed. The theory of reactions in 3N system predicts the ε nn dependence of the FSI cross section being sensitive to the value of a nn . The measurements will be made using the neutron channel RADEX at Moscow meson factory of the Institute for Nuclear Research. The momenta and angles of the two emitted neutrons and the energy of the proton will be measured for each breakup event. The measured dependence of the reaction yield on the relative energy of the two neutrons will be compared to results of the Monte Carlo simulation that includes
Measurement of the spin-dependent structure-functions of the proton and the deuteron
2002-01-01
% NA47 %title \\\\ \\\\The physics motivation of the experiments of the Spin Muon Collaboration is to better understand how the nucleon spin is built-up by its partons and to test the fundamental Bjorken sum rule. \\\\ \\\\The spin-dependent structure functions $g _{1}(x)$ of the proton and the deuteron are determined from the measured cross section asymmetries for deep inelastic scattering of longitudinally polarized muons from longitudinally polarized nucleons. The experiment is similar to the NA2 one of the European Muon Collaboration in which the violation of the Ellis-Jaffe sum rule for the proton was found. \\\\ \\\\The apparatus is the upgraded forward spectrometer which was used originally by the European and New Muon Collaborations. To minimize the systematic uncertainties the target contains two oppositely polarized cells, which were exposed to the muon beam simultaneously. For the experiments in 1991 and 1992 the original EMC polarized target was reinstalled. In 1993 a new polarized target was put into operati...
International Nuclear Information System (INIS)
Blau, R.; Rosenberg, L.; Spruch, L.
1977-01-01
A minimum principle for the calculation of the scattering length, applicable when the ground-state wave function of the target system is known precisely, has been available for some time. When, as is almost always the case, the target wave function is imprecisely known, a minimum principle is available but the simple minimum principle noted above is not applicable. Further, as recent calculations show, numerical instabilities usually arise which severely limit the utility of even an ordinary variational approach. The difficulty, which can be traced to the appearance of singularities in the variational construction, is here removed through the introduction of a minimum principle, not for the true scattering length, but for one associated with a closely connected problem. This guarantees that no instability difficulties can arise as the trial scattering wave function and the trial target wave function are improved. The calculations are little different from those required when the target ground-state wave function is known, and, in fact, the original version of the minimum principle is recovered as the trial target wave function becomes exact. A careful discussion is given of the types of problems to which the method can be applied. In particular, the effects of the Pauli principle, and the existence of a finite number of composite bound states, can be accounted for
International Nuclear Information System (INIS)
Granovsky, A.B.; Inoue, Mitsuteru
2004-01-01
We present a brief review of recent experimental and theoretical results on magnetorefractive effect in magnetic metal-insulator nanogranular alloys with tunnel-type magnetoresistance focusing on its relation with high-frequency spin-dependent tunnelling
Energy Technology Data Exchange (ETDEWEB)
Granovsky, A.B. E-mail: granov@magn.ru; Inoue, Mitsuteru
2004-05-01
We present a brief review of recent experimental and theoretical results on magnetorefractive effect in magnetic metal-insulator nanogranular alloys with tunnel-type magnetoresistance focusing on its relation with high-frequency spin-dependent tunnelling.
Spin-dependent relativistic effect on heavy quarkonium properties in medium
International Nuclear Information System (INIS)
Dong Yubing
1997-01-01
Spin-dependent relativistic effect on the binding and dissociation of the heavy quarkonium in a thermal environment is investigated. The result shows that the interactions could influence the heavy quarkonium properties in medium
Spin-Dependent Cross Sections in Pion Produc- tion
Pintex Collaboration; von Przewoski, B.; Dzemidzic, M.; Doskow, J.; Meyer, H. O.; Pollock, R. E.; Rinckel, T.; Sperisen, F.; Wolanski, M.; Haeberli, W.; Lorentz, B.; Quin, P.; Rathmann, F.; Schwartz, B.; Wise, T.; Daehnick, W.; Flammang, R.; Tedeschi, D.; Pancella, P. V.
1997-04-01
An experiment to measure ΔσL and ΔσT for pion production in pp scattering is in preparation at the Indiana Cooler. Both, pparrowppπ^circ and pparrowpnπ^+ reactions, will be studied. Either two charged particles or the neutron and the proton are detected in the exit channel. The experiment requires the acceleration of longitudinally polarized stored protons. Recently, longitudinally polarized beam has been successfully stored and accelerated to 400 MeV. The experiment uses the Wisconsin/IUCF polarized storage cell target. Upgrades to the experimental setup which has been used previously for a measurement of spin correlation parameters in pp elastic scattering will be discussed. The detector response is studied by means of a Monte Carlo simulation. Expected performance parameters will be presented.
A nonperturbative treatment of spin-dependent interactions of light and heavy quarkonia
International Nuclear Information System (INIS)
Schoeberl, F.
1986-01-01
We propose a nonrelativistic potential model with a regularized Coulomb potential at short range which leads to spin-dependent interactions which are at most as singular as 1/r. The Schroedinger equation is solved numerically including all spin-dependent interactions nonperturbatively. The predicted spectrum of light and heavy quarkonia is in remarkable agreement with experiment. Even the leptonic decay widths as well as the M1 transitions are in agreement with experiment. (Author)
Measurement of the spin dependent structure functions of proton and neutron
International Nuclear Information System (INIS)
Rith, K.
1989-01-01
Recent results from the EMC experiment on the spin dependent structure function g 1 p (x) of the proton are discussed. They suggest that the nucleon spin does not originate from quark spins but rather from angular orbital momentum and gluon contributions. A proposed experiment at HERA is presented which will allow a very accurate measurement of the spin dependent structure functions and their integrals of both proton and neutron and a precise test of the Bjorken sum rule. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Ke, Yougang; Liu, Yachao; He, Yongli; Zhou, Junxiao; Luo, Hailu, E-mail: hailuluo@hnu.edu.cn; Wen, Shuangchun [Laboratory for Spin Photonics, School of Physics and Electronics, Hunan University, Changsha 410082 (China)
2015-07-27
We report the realization of spin-dependent splitting with arbitrary intensity patterns based on all-dielectric metasurfaces. Compared with the plasmonic metasurfaces, the all-dielectric metasurface exhibits more high transmission efficiency and conversion efficiency, which makes it possible to achieve the spin-dependent splitting with arbitrary intensity patterns. Our findings suggest a way for generation and manipulation of spin photons, and thereby offer the possibility of developing spin-based nanophotonic applications.
International Nuclear Information System (INIS)
Bulut, S.; Guelecyuez, M.C.; Kaskas, A.; Tezcan, C.
2007-01-01
H N and singular eigenfunction methods are used to determine the neutron distribution everywhere in a source-free half space with zero incident flux for a linearly anisotropic scattering kernel. The singular eigenfunction expansion of the method of elementary solutions is used. The orthogonality relations of the discrete and continuous eigenfunctions for linearly anisotropic scattering provides the determination of the expansion coefficients. Different expansions of the exit distribution are used: the expansion in powers of μ, the expansion in terms of Legendre polynomials and the expansion in powers of 1/(1+μ). The results are compared to each other. In the second part of our work, the transport equation and the infinite medium Green function are used. The numerical results of the extrapolation length obtained for the different expansions is discussed. (orig.)
International Nuclear Information System (INIS)
Soric, J C; Chen, P Y; Alù, A; Kerkhoff, A; Rainwater, D; Melin, K
2013-01-01
We present the first experimental realization and verification of a three-dimensional stand-alone mantle cloak designed to suppress the total scattering of a finite-length dielectric rod of moderate cross-section. Mantle cloaking has been proposed to realize ultralow-profile conformal covers that may achieve substantial camouflage, transparency and high-performance non-invasive near-field sensing. Here, we realize and verify a mantle cloak for radio-waves. We report an extensive campaign of far- and near-field free-space measurements demonstrating that conformal cloaks can indeed produce strong scattering suppression in all directions and over a relatively broad bandwidth of operation. (paper)
COUPLED-CHANNELS FADDEEV CALCULATION OF THE K(-) d SCATTERING LENGTH
Czech Academy of Sciences Publication Activity Database
Shevchenko, Nina V.
2011-01-01
Roč. 26, 3-4 (2011), s. 558-560 ISSN 0217-751X. [11th International Workshop on Meson Production , Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA AV ČR KJB100480801 Institutional research plan: CEZ:AV0Z10480505 Keywords : Few-body systems * multichannel scattering * antikaon-baryon interaction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.053, year: 2011
Scattering lengths in SU(2) gauge theory with two fundamental fermions
DEFF Research Database (Denmark)
Arthur, R.; Drach, V.; Hansen, Martin Rasmus Lundquist
2014-01-01
We investigate non perturbatively scattering properties of Goldstone Bosons in an SU(2) gauge theory with two Wilson fermions in the fundamental representation. Such a theory can be used to build extensions of the Standard Model that unifies Technicolor and pseudo Goldstone composite Higgs models...... the expected chiral symmetry breaking pattern. We then discuss how to compute them on the lattice and give preliminary results using finite size methods....
Energy Technology Data Exchange (ETDEWEB)
Trotter, D.E. Gonzalez [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: crowell@tunl.duke.edu; Meneses, F. Salinas [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Tornow, W. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)], E-mail: tornow@tunl.duke.edu; Crowell, A.S.; Howell, C.R. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Schmidt, D. [Physikalisch-Technische Bundesanstalt, D-38116, Braunschweig (Germany); Walter, R.L. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States)
2009-02-11
The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the {sup 1}S{sub 0} neutron-neutron and neutron-proton scattering lengths a{sub nn} and a{sub np}, respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E{sub n}=13MeV.
International Nuclear Information System (INIS)
Trotter, D.E. Gonzalez; Meneses, F. Salinas; Tornow, W.; Crowell, A.S.; Howell, C.R.; Schmidt, D.; Walter, R.L.
2009-01-01
The methods employed and the results obtained from measurements and calculations of the detection efficiency for the neutron detectors used at Triangle Universities Nuclear Laboratory (TUNL) in the simultaneous determination of the 1 S 0 neutron-neutron and neutron-proton scattering lengths a nn and a np , respectively, are described. Typical values for the detector efficiency were 0.3. Very good agreement between the different experimental methods and between data and calculation has been obtained in the neutron energy range below E n =13MeV.
International Nuclear Information System (INIS)
Ioffe, A.; Ermakov, O.; Karpikhin, I.; Krupchitsky, P.; Mikula, P.; Lukas, P.; Vrana, M.
2000-01-01
The neutron scattering length of lead isotopes 204 Pb, 207 Pb and 208 Pb are determined by a set of neutron interferometry experiments. The obtained values b (208) =9.494(30) fm, b (207) =9.286(16) fm, b (204) =10.893(78) fm have much higher accuracy then current table data. Together with the precise value of b for natural lead, these results represent a complete set of data and allow one to calculate b (206) =9.221(69) fm, which is in the very good agreement with the present day experimental value. (orig.)
Spin-dependent hot electron transport and nano-scale magnetic imaging of metal/Si structures
International Nuclear Information System (INIS)
Kaidatzis, A.
2008-10-01
In this work, we experimentally study spin-dependent hot electron transport through metallic multilayers (ML), containing single magnetic layers or 'spin-valve' (SV) tri layers. For this purpose, we have set up a ballistic electron emission microscope (BEEM), a three terminal extension of scanning tunnelling microscopy on metal/semiconductor structures. The implementation of the BEEM requirements into the sample fabrication is described in detail. Using BEEM, the hot electron transmission through the ML's was systematically measured in the energy range 1-2 eV above the Fermi level. By varying the magnetic layer thickness, the spin-dependent hot electron attenuation lengths were deduced. For the materials studied (Co and NiFe), they were compared to calculations and other determinations in the literature. For sub-monolayer thickness, a non uniform morphology was observed, with large transmission variations over sub-nano-metric distances. This effect is not yet fully understood. In the imaging mode, the magnetic configurations of SV's were studied under field, focusing on 360 degrees domain walls in Co layers. The effects of the applied field intensity and direction on the DW structure were studied. The results were compared quantitatively to micro-magnetic calculations, with an excellent agreement. From this, it can be shown that the BEEM magnetic resolution is better than 50 nm. (author)
Afanasyev, Leonid
2016-01-01
The Low Energy QCD allows to calculate the ππ and π K scattering lengths with high precision. There are accurate relations between these scattering lengths and π + π − , π − K + , π + K − atoms lifetimes. The experiment on the first observation of π − K + and π + K − atoms is described. The atoms were generated in Nickel and Platinum targets hit by the PS CERN proton beam with momentum of 24 GeV/ c . Moving in the target, part of atoms break up producing characteristic π K pairs (atomic pairs) with small relative momentum Q in their c.m.s. In the experiment, we detected n A = 349 ± 62 (5.6 standard deviations) π − K + and π + K − atomic pairs. The main part of π K pairs are produced in free state. The majority of such particles are generated directly or from short-lived sources as ρ , ω and similar resonances. The electromagnetic interactions in the final state create Coulomb pairs with a known sharp dependence on Q . This effect allows to evaluate the number of these Coulomb pai...
International Nuclear Information System (INIS)
Maltman, K.
1998-01-01
Using the framework of effective chiral Lagrangians, we show that, in order to correctly implement electromagnetism (EM), as generated from the Standard Model, into effective hadronic theories (such as meson-exchange models) it is insufficient to consider only graphs in the low-energy effective theory containing explicit photon lines. The Standard Model requires the presence of contact interactions in the effective theory which are electromagnetic in origin, but which involve no photons in the effective theory. We illustrate the problems which can result from a ''standard'' EM subtraction: i.e., from assuming that removing all contributions in the effective theory generated by graphs with explicit photon lines fully removes EM effects, by considering the case of the s-wave ππ scattering lengths. In this case it is shown that such a subtraction procedure would lead to the incorrect conclusion that the strong interaction isospin-breaking contributions to these quantities were large when, in fact, they are known to vanish at leading order in m d -m u . The leading EM contact corrections for the channels employed in the extraction of the I=0,2 s-wave ππ scattering lengths from experiment are also evaluated. (orig.)
International Nuclear Information System (INIS)
Tornow, W.; Braun, R.T.; Witala, H.
1996-01-01
We review published analyses of the final-state-interaction enhancement observed in proton energy distributions obtained from kinematically incomplete neutron-deuteron breakup experiments. We compare the results derived from these analyses for the neutron-neutron scattering length, a nn with our results based on a rigorous treatment of the three-nucleon Faddeev equations in conjunction with the use of realistic nucleon-nucleon potentials. Our values for a nn deviate outside the quoted uncertainties from the ones obtained in the previous analyses where simplified nucleon-nucleon interaction models were employed. In contrast to the previous determinations, the present results for a nn are in clear disagreement with the values for a nn based on π - -deuteron capture experiments. Unless inconsistencies in the experimental neutron-deuteron breakup data at low energies can be resolved and the influence of possible three-nucleon-force effects can be reliably determined, we recommend that one not resort to the kinematically incomplete neutron-deuteron breakup reaction as a tool for determining a quantity as important for nuclear and particle physics as is the neutron-neutron scattering length a nn . (author)
International Nuclear Information System (INIS)
Enik, T.L.; Mitsyna, L.V.; Nikolenko, V.G.; Oprea, I.A.; Parzhitsky, S.S.; Popov, A.B.; Samosvat, G.S.; Vtiuryn, V.A.
1999-01-01
Relationship between the n,e scattering length, b ne , the neutron mean square charge radius n 2 > and anomalous magnetic moment μ n , the quantities which characterize the internal structure of the neutron, was investigated. The performed analysis showed that in the framework of the modern cloudy bag model (CBM) of the nucleon the values of b ne is determined by the value of n 2 > without the so-called Foldy term being taken into account, while in the framework of the phenomenological Foldy approach the experimental values of ne > obtained up to date can be described only by this Foldy term within an accuracy of about 10%, i.e. by the anomalous magnetic moment of the neutron, μ n . Then a necessity is obvious to obtain b ne with higher accuracy than in previous experiments. To remove the contradictions in the experimental b ne estimates, new experiments to measure the energy dependence of the slow neutron scattering cross section by 86 Kr and scattering anisotropy on Xe isotopes, have been proposed. The investigation has been performed at Frank Laboratory of Neutron Physics, JINR. (authors)
Varghese, Babu; Rajan, Vinayakrishnan; van Leeuwen, Ton G.; Steenbergen, Wiendelt
2007-01-01
In optical Doppler measurements, the path length of the light is unknown. To facilitate quantitative measurements, we develop a phase-modulated Mach-Zehnder interferometer with separate fibers for illumination and detection. With this setup, path-length-resolved dynamic light scattering measurements
Vodopyanov, B P
2010-05-12
The influence of the spin-dependent phase shifts (SDPSs) associated with the electronic reflection and transmission amplitudes acquired by electrons upon scattering at the potential barrier on the Andreev reflection probability of electron and hole excitations for a ferromagnet/isolator/d-wave superconductor (FIS) contact and on the charge conductance of the FIS contact is studied. Various superconductor orientations are considered. It has been found that for strong ferromagnets and ultrathin interface potential for the {110} oriented d-wave superconductor the presence of the SDPS can lead to the appearance of finite-voltage peaks in the charge conductance of the F/I/d-wave superconductor contact. On the contrary, for the {100} orientation of the d-wave superconductor the presence of the SDPS can lead to restoration of the zero-voltage peak and suppression of finite-voltage peaks. The spin-dependent amplitudes of the Andreev reflection probability and energy levels of the spin-dependent Andreev bound states are found.
Limits on Spin-Dependent WIMP-Nucleon Cross Section Obtained from the Complete LUX Exposure
Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fallon, S. R.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Velan, V.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration
2017-06-01
We present experimental constraints on the spin-dependent WIMP-nucleon elastic cross sections from the total 129.5 kg yr exposure acquired by the Large Underground Xenon experiment (LUX), operating at the Sanford Underground Research Facility in Lead, South Dakota (USA). A profile likelihood ratio analysis allows 90% C.L. upper limits to be set on the WIMP-neutron (WIMP-proton) cross section of σn=1.6 ×10-41 cm2 (σp=5 ×10-40 cm2 ) at 35 GeV c-2 , almost a sixfold improvement over the previous LUX spin-dependent results. The spin-dependent WIMP-neutron limit is the most sensitive constraint to date.
Determining the spin dependent mean free path in Co90Fe10 using giant magnetoresistance
Shakespear, K. F.; Perdue, K. L.; Moyerman, S. M.; Checkelsky, J. G.; Harberger, S. S.; Tamboli, A. C.; Carey, M. J.; Sparks, P. D.; Eckert, J. C.
2005-05-01
The spin dependent mean free path in Co90Fe10 is determined as a function of temperature down to 5K using two different spin valve structures. At 5K the spin dependent mean free path for one structure was measured to be 9.4±1.4nm, decreasing by a factor of 3 by 350K. For the other structure, it is 7.5±0.5nm at 5K and decreased by a factor of 1.5 by 350K. In both cases, the spin dependent mean free path approaches the typical thickness of ferromagnetic layers in spin valves at room temperature and, thus, has an impact on the choice of design parameters for the development of new spintronic devices.
Spin-dependent tunneling transport into CrO2 nanorod devices with nonmagnetic contacts.
Song, Yipu; Schmitt, Andrew L; Jin, Song
2008-08-01
Single-crystal nanorods of half-metallic chromium dioxide (CrO2) were synthesized and structurally characterized. Spin-dependent electrical transport was investigated in individual CrO2 nanorod devices contacted with nonmagnetic metallic electrodes. Negative magnetoresistance (MR) was observed at low temperatures due to the spin-dependent direct tunneling through the contact barrier and the high spin polarization in the half-metallic nanorods. The magnitude of this negative magnetoresistance decreases with increasing bias voltage and temperature due to spin-independent inelastic hopping through the barrier, and a small positive magnetoresistance was found at room temperature. It is believed that the contact barrier and the surface state of the nanorods have great influence on the spin-dependent transport limiting the magnitude of MR effect in this first attempt at spin filter devices of CrO2 nanorods with nonmagnetic contacts.
Frey, S; Weysser, F; Meyer, H; Farago, J; Fuchs, M; Baschnagel, J
2015-02-01
We present molecular-dynamics simulations for a fully flexible model of polymer melts with different chain length N ranging from short oligomers (N = 4) to values near the entanglement length (N = 64). For these systems we explore the structural relaxation of the supercooled melt near the critical temperature T c of mode-coupling theory (MCT). Coherent and incoherent scattering functions are analyzed in terms of the idealized MCT. For temperatures T > T c we provide evidence for the space-time factorization property of the β relaxation and for the time-temperature superposition principle (TTSP) of the α relaxation, and we also discuss deviations from these predictions for T ≈ T c. For T larger than the smallest temperature where the TTSP holds we perform a quantitative analysis of the dynamics with the asymptotic MCT predictions for the late β regime. Within MCT a key quantity, in addition to T c, is the exponent parameter λ. For the fully flexible polymer models studied we find that λ is independent of N and has a value (λ = 0.735 ) typical of simple glass-forming liquids. On the other hand, the critical temperature increases with chain length toward an asymptotic value T c (∞) . This increase can be described by T c (∞) - T c(N) ∼ 1/N and may be interpreted in terms of the N dependence of the monomer density ρ, if we assume that the MCT glass transition is ruled by a soft-sphere-like constant coupling parameter Γ c = ρ c T c (-1/4), where ρ c is the monomer density at T c. In addition, we also estimate T c from a Hansen-Verlet-like criterion and MCT calculations based on structural input from the simulation. For our polymer model both the Hansen-Verlet criterion and the MCT calculations suggest T c to decrease with increasing chain length, in contrast to the direct analysis of the simulation data.
International Nuclear Information System (INIS)
Witala, H.; Hueber, D.; Gloeckle, W.; Tornow, W.; Gonzalez Trotter, D.E.
1996-01-01
Data for the neutron-neutron final-state-interaction cross section obtained recently in a kinematically complete neutron-deuteron breakup experiment have been reanalyzed using rigorous solutions of the three-nucleon Faddeev equations with realistic nucleon-nucleon interactions. A discrepancy was found with respect to a recent analysis based on the W-matrix approximation to the Paris potential. We also estimate theoretical uncertainties in extracting the neutron-neutron scattering length resulting from the use of different nucleon-nucleon interactions and the possible action of the two pion-exchange three-nucleon force. We find that there exists a certain production angle for the interacting neutron-neutron pair where the uncertainties become minimal. (author)
Charge symmetry breaking in spin dependent parton distributions and the Bjorken sum rule
International Nuclear Information System (INIS)
Cloet, I.C.; Horsley, R.; Londergan, J.T.
2012-04-01
We present the rst determination of charge symmetry violation (CSV) in the spin-dependent parton distribution functions of the nucleon. This is done by determining the rst two Mellin moments of the spin-dependent parton distribution functions of the octet baryons from N f =2+1 lattice simulations. The results are compared with predictions from quark models of nucleon structure. We discuss the contribution of partonic spin CSV to the Bjorken sum rule, which is important because the CSV contributions represent the only partonic corrections to the Bjorken sum rule.
Charge symmetry breaking in spin dependent parton distributions and the Bjorken sum rule
Energy Technology Data Exchange (ETDEWEB)
Cloet, I.C. [Adelaide Univ, SA (Australia). CSSM, School of Chemistry and Physics; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Londergan, J.T. [Indiana Univ., Bloomington, IN (US). Dept. of Physics and Center for Exploration of Energy and Matter] (and others)
2012-04-15
We present the rst determination of charge symmetry violation (CSV) in the spin-dependent parton distribution functions of the nucleon. This is done by determining the rst two Mellin moments of the spin-dependent parton distribution functions of the octet baryons from N{sub f}=2+1 lattice simulations. The results are compared with predictions from quark models of nucleon structure. We discuss the contribution of partonic spin CSV to the Bjorken sum rule, which is important because the CSV contributions represent the only partonic corrections to the Bjorken sum rule.
Energy Technology Data Exchange (ETDEWEB)
Scopel, Stefano; Yu, Hyeonhye, E-mail: scopel@sogang.ac.kr, E-mail: skyh2yu@gmail.com [Department of Physics, Sogang University, Seoul (Korea, Republic of)
2017-04-01
We discuss strategies to make inferences on the thermal relic abundance of a Weakly Interacting Massive Particle (WIMP) when the same effective dimension-six operator that explains an experimental excess in direct detection is assumed to drive decoupling at freeze-out, and apply them to the explicit scenario of WIMP inelastic up-scattering with spin-dependent couplings to protons (proton-philic Spin-dependent Inelastic Dark Matter, pSIDM), a phenomenological set-up containing two Dark Matter (DM) particles χ{sub 1} and χ{sub 2} with masses m {sub χ}= m {sub χ{sub 1}} and m {sub χ{sub 2}}= m {sub χ}+δ that we have shown in a previous paper to explain the DAMA effect in compliance with the constraints from other detectors. We also update experimental constraints on pSIDM, extend the analysis to the most general spin-dependent momentum-dependent interactions allowed by non-relativistic Effective Field Theory (EFT), and consider for the WIMP velocity distribution in our Galaxy f ( v ) both a halo-independent approach and a standard Maxwellian. Under these conditions we find that the DAMA effect can be explained in terms of the particle χ{sub 1} in compliance with all the other constraints for all the analyzed EFT couplings and also for a Maxwellian f ( v ). As far as the relic abundance is concerned, we show that the problem of calculating it by using direct detection data to fix the model parameters is affected by a strong sensitivity on f ( v ) and by the degeneracy between the WIMP local density ρ{sub χ} and the WIMP-nucleon scattering cross section, since ρ{sub χ} must be rescaled with respect to the observed DM density in the neighborhood of the Sun when the calculated relic density Ω is smaller than the observed one Ω{sub 0}. As a consequence, a DM direct detection experiment is not directly sensitive to the physical cut-off scale of the EFT, but on some dimensional combination that does not depend on the actual value of Ω. However, such degeneracy
Sum rule measurements of the spin-dependent compton amplitude (nucleon spin structure at Q2 = 0)
International Nuclear Information System (INIS)
Babusci, D.; Giordano, G.; Baghaei, H.; Cichocki, A.; Blecher, M.; Breuer, M.; Commeaux, C.; Didelez, J.P.; Caracappa, A.; Fan, Q.
1995-01-01
Energy weighted integrals of the difference in helicity-dependent photo-production cross sections (σ 1/2 - σ 3/2 ) provide information on the nucleon's Spin-dependent Polarizability (γ), and on the spin-dependent part of the asymptotic forward Compton amplitude through the Drell-Hearn-Gerasimov (DHG) sum rule. (The latter forms the Q 2 =0 limit of recent spin-asymmetry experiments in deep-inelastic lepton-scattering.) There are no direct measurements of σ 1/2 or σ 3/2 , for either the proton or the neutron. Estimates from current π-photo-production multipole analyses, particularly for the proton-neutron difference, are in good agreement with relativistic-l-loop Chiral calculations (χPT) for γ but predict large deviations from the DHG sum rule. Either (a) both the 2-loop corrections to the Spin-Polarizability are large and the existing multipoles are wrong, or (b) modifications to the Drell-Hearn-Gerasimov sum rule are required to fully describe the isospin structure of the nucleon. The helicity-dependent photo-reaction amplitudes, for both the proton and the neutron, will be measured at LEGS from pion-threshold to 470 MeV. In these double-polarization experiments, circularly polarized photons from LEGS will be used with SPHICE, a new frozen-spin target consisting of rvec H · rvec D in the solid phase. Reaction channels will be identified in SASY, a large detector array covering about 80% of 4π. A high degree of symmetry in both target and detector will be used to minimize systematic uncertainties
Spin-dependent Seebeck coefficients of Ni80Fe20 and Co in nanopillar spin valves
Dejene, F. K.; Flipse, J.; van Wees, B. J.
2012-01-01
We have experimentally determined the spin-dependent Seebeck coefficient of permalloy (Ni80Fe20) and cobalt (Co) using nanopillar spin valve devices, a stack of two ferromagnetic layers separated by a nonmagnetic layer. The devices were specifically designed to separate heat-related effects from
Micromagnetic Design of Spin Dependent Tunnel Junctions for Optimized Sensing Performance
National Research Council Canada - National Science Library
Tondra, Mark; Daughton, James M; Nordman, Catherine; Wang, Dexin; Taylor, John
1999-01-01
Pinned Spin Dependent Tunneling (SDT) devices have been fabricated into high sensitivity magnetic field sensors with many favorable properties including high sensitivity (̃ 10 umOe / Hz @ 1 Hz and ̃ 100 nOe / Hz @ > 10 kHz...
Nanoscale spin-dependent transport of electrons and holes in Si-ferromagnet structures
Ul Haq, E.
Given the rapid development of magnetic data storage and spin-electronics into the realm of nanotechnology, the understanding of the spin-dependent electronic transport and switching behavior of magnetic structures at the nanoscale is an important issue. We have developed spin-sensitive techniques
Nuclear-spin-dependent parity-nonconserving effects in thallium, lead and bismuth atoms
International Nuclear Information System (INIS)
Khriplovich, I.B.
1994-01-01
Nuclear-spin-dependent P-odd optical activity in atomic Tl, Pb and Bi is calculated. Its magnitude is expressed analytically through the main contribution to the optical rotation, which is independent of nuclear spin. The accuracy of results is discussed. 31 refs., 2 tabs
Yan, Jiawei; Wang, Shizhuo; Xia, Ke; Ke, Youqi
2018-01-01
We present first-principles analysis of interfacial disorder effects on spin-dependent tunneling statistics in thin Fe/MgO/Fe magnetic tunnel junctions. We find that interfacial disorder scattering can significantly modulate the tunneling statistics in the minority spin of the parallel configuration (PC) while all other spin channels remain dominated by the Poissonian process. For the minority-spin channel of PC, interfacial disorder scattering favors the formation of resonant tunneling channels by lifting the limitation of symmetry conservation at low concentration, presenting an important sub-Poissonian process in PC, but is destructive to the open channels at high concentration. We find that the important modulation of tunneling statistics is independent of the type of interfacial disorder. A bimodal distribution function of transmission with disorder dependence is introduced and fits very well our first-principles results. The increase of MgO thickness can quickly change the tunneling from a sub-Poissonian to Poissonian dominated process in the minority spin of PC with disorder. Our results provide a sensitive detection method of an ultralow concentration of interfacial defects.
International Nuclear Information System (INIS)
Windmolders, R.
1989-01-01
In this paper the following topics are reviewed: 1. the structure functions measured in deep inelastic e-N, μ-N and ν-N scattering; 2. nuclear effects on the structure functions; 3. nuclear effects on the fragmentation functions; 4. the spin dependent structure functions and their interpretation in terms of nucleon constituents. (orig./HSI)
International Nuclear Information System (INIS)
Broome, J.
1965-11-01
The programme SCATTER is a KDF9 programme in the Egtran dialect of Fortran to generate normalized angular distributions for elastically scattered neutrons from data input as the coefficients of a Legendre polynomial series, or from differential cross-section data. Also, differential cross-section data may be analysed to produce Legendre polynomial coefficients. Output on cards punched in the format of the U.K. A. E. A. Nuclear Data Library is optional. (author)
International Nuclear Information System (INIS)
Efimov, G.V.; Ivanov, M.A.; Rusetskij, A.G.
1989-01-01
The S-wave πN-scattering lengths and the (pπ - )-atom lifetime are in the quark confinement model. Nucleon is treated as a quark-diquark system. The fulfillment of the Weinberg-Tomozawa relations is checked. The agreement is achieved with the experiment and with the results obtained within other approaches. 32 refs.; 5 figs.; 2 tabs
Static spin-dependent forces between heavy quarks in the classical approximation to dual QCD
International Nuclear Information System (INIS)
Baker, M.; Ball, J.S.; Zachariasen, F.
1991-01-01
We compute the static spin-dependent forces V S (R) (proportional to σ 1 ·σ 2 ) and V T (R) (proportional to 3σ 1 ·Rσ 2 ·R-σ 1 ·σ 2 ) between two quarks separated by R. This is done by treating the (weak) spin-dependent effects as a perturbation on the spin-independent potentials and fields computed earlier for dual QCD. What results is a definite prediction for the heavy-quark potentials which are similar to, but different in form from, those used in phenomenological treatments. Calculations of the masses and splittings of heavy-quark states using our potentials will provide a further test of the dual superconductor picture of QCD
Optical control of spin-dependent thermal transport in a quantum ring
Abdullah, Nzar Rauf
2018-05-01
We report on calculation of spin-dependent thermal transport through a quantum ring with the Rashba spin-orbit interaction. The quantum ring is connected to two electron reservoirs with different temperatures. Tuning the Rashba coupling constant, degenerate energy states are formed leading to a suppression of the heat and thermoelectric currents. In addition, the quantum ring is coupled to a photon cavity with a single photon mode and linearly polarized photon field. In a resonance regime, when the photon energy is approximately equal to the energy spacing between two lowest degenerate states of the ring, the polarized photon field can significantly control the heat and thermoelectric currents in the system. The roles of the number of photon initially in the cavity, and electron-photon coupling strength on spin-dependent heat and thermoelectric currents are presented.
Spin-dependent electrical transport in Fe-MgO-Fe heterostructures
Directory of Open Access Journals (Sweden)
A A Shokri
2016-09-01
Full Text Available In this paper, spin-dependent electrical transport properties are investigated in a single-crystal magnetic tunnel junction (MTJ which consists of two ferromagnetic Fe electrodes separated by an MgO insulating barrier. These properties contain electric current, spin polarization and tunnel magnetoresistance (TMR. For this purpose, spin-dependent Hamiltonian is described for Δ1 and Δ5 bands in the transport direction. The transmission is calculated by Green's function formalism based on a single-band tight-binding approximation. The transport properties are investigated as a function of the barrier thickness in the limit of coherent tunneling. We have demonstrated that dependence of the TMR on the applied voltage and barrier thickness. Our numerical results may be useful for designing of spintronic devices. The numerical results may be useful in designing of spintronic devices.
Realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect
Energy Technology Data Exchange (ETDEWEB)
Ling, Xiaohui [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Department of Physics and Electronic Information Science, Hengyang Normal University, Hengyang 421002 (China); Yi, Xunong [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Zhou, Xinxing; Liu, Yachao; Shu, Weixing; Wen, Shuangchun [Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Luo, Hailu, E-mail: hailuluo@hnu.edu.cn [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China)
2014-10-13
We report the realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect. By breaking the rotational symmetry of a cylindrical vector beam, the intrinsic vortex phases that the two spin components of the vector beam carries, which is similar to the geometric Pancharatnam-Berry phase, are no longer continuous in the azimuthal direction, and leads to observation of spin accumulation at the opposite edge of the beam. Due to the inherent nature of the phase and independency of light-matter interaction, the observed photonic spin Hall effect is intrinsic. Modulating the topological charge of the vector beam, the spin-dependent splitting can be enhanced and the direction of spin accumulation is switchable. Our findings may provide a possible route for generation and manipulation of spin-polarized photons, and enables spin-based photonics applications.
Large current modulation and spin-dependent tunneling of vertical graphene/MoS2 heterostructures.
Myoung, Nojoon; Seo, Kyungchul; Lee, Seung Joo; Ihm, G
2013-08-27
Vertical graphene heterostructures have been introduced as an alternative architecture for electronic devices by using quantum tunneling. Here, we present that the current on/off ratio of vertical graphene field-effect transistors is enhanced by using an armchair graphene nanoribbon as an electrode. Moreover, we report spin-dependent tunneling current of the graphene/MoS2 heterostructures. When an atomically thin MoS2 layer sandwiched between graphene electrodes becomes magnetic, Dirac fermions with different spins feel different heights of the tunnel barrier, leading to spin-dependent tunneling. Our finding will develop the present graphene heterostructures for electronic devices by improving the device performance and by adding the possibility of spintronics based on graphene.
International Nuclear Information System (INIS)
Aprile-Giboni, E.; Cantale, G.; Hausammann, R.
1983-01-01
Using the PM1 polarized proton beam at SIN and a polarized target, the elastic pp scattering as well as the inelastic channel pp → π + d have been studied between 400 and 600 MeV. For the elastic reaction, a sufficient number of spin dependent parameters has been measured in order to do a direct reconstruction of the scattering matrix between 38 0 /sub cm/ and 90 0 /sub cm/. 10 references, 6 figures
Spin-dependent recombination involving oxygen-vacancy complexes in silicon
Franke, David P.; Hoehne, Felix; Vlasenko, Leonid S.; Itoh, Kohei M.; Brandt, Martin S.
2014-01-01
Spin-dependent relaxation and recombination processes in $\\gamma$-irradiated $n$-type Czochralski-grown silicon are studied using continuous wave (cw) and pulsed electrically detected magnetic resonance (EDMR). Two processes involving the SL1 center, the neutral excited triplet state of the oxygen-vacancy complex, are observed which can be separated by their different dynamics. One of the processes is the relaxation of the excited SL1 state to the ground state of the oxygen-vacancy complex, t...
Myoung, Nojoon; Seo, Kyungchul; Lee, Seung Joo; Ihm, Gukhyung
2013-01-01
Vertical graphene heterostructures have been introduced as an alternative architecture for electronic devices by using quantum tunneling. Here, we present that the current on/off ratio of vertical graphene field-effect transistors is enhanced by using an armchair graphene nanoribbon as an electrode. Moreover, we report spin-dependent tunneling current of the graphene/MoS2 heterostructures. When an atomically thin MoS2 layer sandwiched between graphene electrodes becomes magnetic, Dirac fermio...
The spin-dependent neutralino-nucleus form factor for 127I
International Nuclear Information System (INIS)
Ressell, M.T.
1996-01-01
We present the results of detailed shell model calculations of the spin-dependent elastic form factor for the nucleus 127 I. the calculations were performed in extremely large model spaces which adequately describe the configuration mixing in this nucleus. Good agreement between the calculated and experimental values of the magnetic moment are found. Other nuclear observables are also compared to experiment. The dependence of the form factor upon the model space and effective interaction is discussed
Spin dependent surface recombination in silicon p-n junctions: the effect of irradiation
Energy Technology Data Exchange (ETDEWEB)
Kaplan, D [Laboratoire Central de Recherches, 91 - Corbeville par Orsay (France); Pepper, M [Cambridge Univ. (UK). Cavendish Lab.
1980-06-01
The results are presented of an investigation of spin dependent recombination in (100) oriented, gate controlled Si diodes irradiated by 30 keV electrons. After irradiation, recombination at the Si-SiO/sub 2/ interface is increased, and saturation of the spin resonance increases the diode forward current by 5 parts in 10/sup 4/. The results cannot be described by a conventional Shockley-Read recombination model. An alternative picture is proposed involving recombination between trapped electrons and trapped holes.
Origin of spin-dependent asymmetries in electron transmission through ultrathin ferromagnetic films
International Nuclear Information System (INIS)
Gokhale, M.P.; Mills, D.L.
1991-01-01
We present theoretical calculations of exchange asymmetries in the transmission of electrons through ultrathin films of ferromagnetic Fe. The results account nicely for the magnitude of the asymmetries observed by Pappas et al. in photoemission studies of Cu covered by an ultrathin film of Fe. We argue that exchange asymmetry in the transmissivity of the Fe film, rather than the spin dependence of the electron mean free path, is responsible for the effects reported by these authors
Spin-dependent electron many-body effects in GaAs
Nemec, P.; Kerachian, Y.; van Driel, H. M.; Smirl, Arthur L.
2005-12-01
Time- and polarization-resolved differential transmission measurements employing same and oppositely circularly polarized 150fs optical pulses are used to investigate spin characteristics of conduction band electrons in bulk GaAs at 295K . Electrons and holes with densities in the 2×1016cm-3-1018cm-3 range are generated and probed with pulses whose center wavelength is between 865 and 775nm . The transmissivity results can be explained in terms of the spin sensitivity of both phase-space filling and many-body effects (band-gap renormalization and screening of the Coulomb enhancement factor). For excitation and probing at 865nm , just above the band-gap edge, the transmissivity changes mainly reflect spin-dependent phase-space filling which is dominated by the electron Fermi factors. However, for 775nm probing, the influence of many-body effects on the induced transmission change are comparable with those from reduced phase space filling, exposing the spin dependence of the many-body effects. If one does not take account of these spin-dependent effects one can misinterpret both the magnitude and time evolution of the electron spin polarization. For suitable measurements we find that the electron spin relaxation time is 130ps .
''Spin-dependent'' μ → e conversion on light nuclei
International Nuclear Information System (INIS)
Davidson, Sacha; Saporta, Albert; Kuno, Yoshitaka
2018-01-01
The experimental sensitivity to μ → e conversion will improve by four or more orders of magnitude in coming years, making it interesting to consider the ''spin-dependent'' (SD) contribution to the rate. This process does not benefit from the atomic-number-squared enhancement of the spin-independent (SI) contribution, but probes different operators. We give details of our recent estimate of the spin-dependent rate, expressed as a function of operator coefficients at the experimental scale. Then we explore the prospects for distinguishing coefficients or models by using different targets, both in an EFT perspective, where a geometric representation of different targets as vectors in coefficient space is introduced, and also in three leptoquark models. It is found that comparing the rate on isotopes with and without spin could allow one to detect spin-dependent coefficients that are at least a factor of few larger than the spin-independent ones. Distinguishing among the axial, tensor and pseudoscalar operators that induce the SD rate would require calculating the nuclear matrix elements for the second two. Comparing the SD rate on nuclei with an odd proton vs. odd neutron could allow one to distinguish operators involving u quarks from those involving d quarks; this is interesting because the distinction is difficult to make for SI operators. (orig.)
''Spin-dependent'' μ → e conversion on light nuclei
Energy Technology Data Exchange (ETDEWEB)
Davidson, Sacha; Saporta, Albert [IPNL, CNRS/IN2P3, Villeurbanne (France); Universite Claude Bernard Lyon 1, Villeurbanne (France); Universite de Lyon, Lyon (France); Kuno, Yoshitaka [Osaka University, Department of Physics, Toyonaka, Osaka (Japan)
2018-02-15
The experimental sensitivity to μ → e conversion will improve by four or more orders of magnitude in coming years, making it interesting to consider the ''spin-dependent'' (SD) contribution to the rate. This process does not benefit from the atomic-number-squared enhancement of the spin-independent (SI) contribution, but probes different operators. We give details of our recent estimate of the spin-dependent rate, expressed as a function of operator coefficients at the experimental scale. Then we explore the prospects for distinguishing coefficients or models by using different targets, both in an EFT perspective, where a geometric representation of different targets as vectors in coefficient space is introduced, and also in three leptoquark models. It is found that comparing the rate on isotopes with and without spin could allow one to detect spin-dependent coefficients that are at least a factor of few larger than the spin-independent ones. Distinguishing among the axial, tensor and pseudoscalar operators that induce the SD rate would require calculating the nuclear matrix elements for the second two. Comparing the SD rate on nuclei with an odd proton vs. odd neutron could allow one to distinguish operators involving u quarks from those involving d quarks; this is interesting because the distinction is difficult to make for SI operators. (orig.)
Hysteresis loops of spin-dependent electronic current in a paramagnetic resonant tunnelling diode
International Nuclear Information System (INIS)
Wójcik, P; Spisak, B J; Wołoszyn, M; Adamowski, J
2012-01-01
Nonlinear properties of the spin-dependent electronic transport through a semiconductor resonant tunnelling diode with a paramagnetic quantum well are considered. The spin-dependent Wigner–Poisson model of the electronic transport and the two-current Mott’s formula for the independent spin channels are applied to determine the current–voltage curves of the nanodevice. Two types of the electronic current hysteresis loops are found in the current–voltage characteristics for both the spin components of the electronic current. The physical interpretation of these two types of the electronic current hysteresis loops is given based on the analysis of the spin-dependent electron densities and the potential energy profiles. The differences between the current–voltage characteristics for both the spin components of the electronic current allow us to explore the changes of the spin polarization of the current for different electric fields and determine the influence of the electronic current hysteresis on the spin polarization of the current flowing through the paramagnetic resonant tunnelling diode. (paper)
The Spin-dependent Structure Function of the Proton $g_{1}^p$ and a Test of the Bjorken Sum Rule
Alekseev, M.G.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Austregesilo, A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Chaberny, D.; Cotic, D.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Crespo, M.L.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Efremov, A.; El Alaoui, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franco, C.; Friedrich, J.M.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gazda, R.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmuller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Haas, F.; von Harrach, D.; Hasegawa, T.; Heinsius, F.H.; Hermann, R.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Hoppner, Ch.; d'Hose, N.; Ilgner, C.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jasinski, P.; Jegou, G.; Joosten, R.; Kabuss, E.; Kafer, W.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konopka, R.; Konorov, I.; Konstantinov, V.F.; Korzenev, A.; Kotzinian, A.M.; Kouznetsov, O.; Kowalik, K.; Kramer, M.; Kral, A.; Kroumchtein, Z.V.; Kuhn, R.; Kunne, F.; Kurek, K.; Lauser, L.; Le Goff, J.M.; Lednev, A.A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Liska, T.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Mann, A.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Massmann, F.; Matsuda, T.; Maximov, A.N.; Meyer, W.; Michigami, T.; Mikhailov, Yu.V.; Moinester, M.A.; Mutter, A.; Nagaytsev, A.; Nagel, T.; Nassalski, J.; Negrini, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Nunes, A.S.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pawlukiewicz-Kaminska, B.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.V.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Pretz, J.; Quintans, C.; Rajotte, J.F.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ryabchikov, D.I.; Samoylenko, V.D.; Sandacz, A.; Santos, H.; Sapozhnikov, M.G.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schmitt, L.; Schluter, T.; Schopferer, S.; Schroder, W.; Shevchenko, O.Yu.; Siebert, H.W.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sosio, S.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Sulej, R.; Takekawa, S.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Uhl, S.; Uman, I.; Virius, M.; Vlassov, N.V.; Vossen, A.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhao, J.; Zhuravlev, N.; Zvyagin, A.
2010-01-01
The inclusive double-spin asymmetry, $A_{1}^{p}$, has been measured at COMPASS in deepinelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range Q2 > 1 (GeV/c)^2, 0.004 < x < 0.7 and improve the statistical precision of g_{1}^{p}(x) by a factor of two in the region x < 0.02. The new proton asymmetries are combined with those previously published for the deuteron to extract the non-singlet spin-dependent structure function g_1^NS(x,Q2). The isovector quark density, Delta_q_3(x,Q2), is evaluated from a NLO QCD fit of g_1^NS. The first moment of Delta_q3 is in good agreement with the value predicted by the Bjorken sum rule and corresponds to a ratio of the axial and vector coupling constants g_A/g_V = 1.28+-0.07(stat)+-0.10(syst).
Morphology effects on spin-dependent transport and recombination in polyfluorene thin films
Miller, Richards; van Schooten, K. J.; Malissa, H.; Joshi, G.; Jamali, S.; Lupton, J. M.; Boehme, C.
2016-12-01
We have studied the role of spin-dependent processes on conductivity in polyfluorene (PFO) thin films by preforming continuous wave (cw) electrically detected magnetic resonance (EDMR) spectroscopy at temperatures between 10 K and room temperature using microwave frequencies between about 1 GHz and 20 GHz, as well as pulsed EDMR at the X band (10 GHz). Variable frequency EDMR allows us to establish the role of spin-orbit coupling in spin-dependent processes whereas pulsed EDMR allows for the observation of coherent spin motion effects. We used PFO for this study in order to allow for the investigation of the effects of microscopic morphological ordering since this material can adopt two distinct intrachain morphologies: an amorphous (glassy) phase, in which monomer units are twisted with respect to each other, and an ordered (β) phase, where all monomers lie within one plane. In thin films of organic light-emitting diodes, the appearance of a particular phase can be controlled by deposition parameters and solvent vapor annealing, and is verified by electroluminescence spectroscopy. Under bipolar charge-carrier injection conditions, we conducted multifrequency cw EDMR, electrically detected Rabi spin-beat experiments, and Hahn echo and inversion-recovery measurements. Coherent echo spectroscopy reveals electrically detected electron-spin-echo envelope modulation due to the coupling of the carrier spins to nearby nuclear spins. Our results demonstrate that, while conformational disorder can influence the observed EDMR signals, including the sign of the current changes on resonance as well as the magnitudes of local hyperfine fields and charge-carrier spin-orbit interactions, it does not qualitatively affect the nature of spin-dependent transitions in this material. In both morphologies, we observe the presence of at least two different spin-dependent recombination processes. At room temperature and 10 K, polaron-pair recombination through weakly spin-spin coupled
Final COMPASS results on the deuteron spin-dependent structure function g1d and the Bjorken sum rule
Directory of Open Access Journals (Sweden)
C. Adolph
2017-06-01
Full Text Available Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV/c24GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2. Towards lowest accessible values of x, g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c2=0.32±0.02stat±0.04syst±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.
Hoi, Bui Dinh; Yarmohammadi, Mohsen
2018-04-01
The spin-dependent electrical conductivity of counterparts of graphene, transition-metal dichalcogenides (TMDs) and group-IV nanosheets, have investigated by a magnetic exchange field (MEF)-induction to gain the electronic transport properties of charge carriers. We have implemented a k.p Hamiltonian model through the Kubo-Greenwood formalism in order to address the dynamical behavior of correlated Dirac fermions. Tuning the MEF enables one to control the effective mass of carriers in group-IV and TMDs, differently. We have found the Dirac-like points in a new quantum anomalous Hall (QAH) state at strong MEFs for both structures. For both cases, a broad peak in electrical conductivity originated from the scattering rate and entropy is observed. Spin degeneracy at some critical MEFs is another remarkable point. We have found that in the limit of zero or uniform MEFs with respect to the spin-orbit interaction, the large resulting electrical conductivity depends on the spin sub-bands in group-IV and MLDs. Featuring spin-dependent electronic transport properties, one can provide a new scenario for future possible applications.
Spin-dependent level density in interacting Boson-Fermion-Fermion model of the Odd-Odd Nucleus 196Au
International Nuclear Information System (INIS)
Kabashi, S.; Bekteshi, S.; Ahmetaj, S.; Shaqiri, Z.
2009-01-01
The level density of the odd-odd nucleus 196 Au is investigated in the interacting boson-fermion-fermion model (IBFFM) which accounts for collectivity and complex interaction between quasiparticle and collective modes.The IBFFM spin-dependent level densities show high-spin reduction with respect to Bethe formula.This can be well accounted for by a modified spin-dependent level density formula. (authors)
The role of the axial anomaly in determining spin-dependent parton distributions
International Nuclear Information System (INIS)
Carlitz, R.D.; Collins, J.C.; Mueller, A.H.
1989-01-01
It is shown that the forward matrix elements of j 5 μ , the flavor singlet axial vector current, do not measure the helicity carried by quarks and anti-quarks but also include a spin-dependent gluonic component due to the anomaly. Detailed phenomenological and field theoretic reasons are given for the necessity of a gluonic component in the matrix element of j 5 μ . The first higher order corrections to the basic box and triangle graphs are discussed and shown not to modify the conclusions drawn in the leading order calculation. We close with a few comments on the possible phenomenological implications of the anomalous contribution. 25 refs., 6 figs
New measurements of spin-dependent n-p cross sections
International Nuclear Information System (INIS)
Raichle, B. W.; Gould, C. R.; Haase, D. G.; Seely, M. L.; Walston, J. R.; Tornow, W.; Wilburn, W. S.; Penttilae, S. I.; Hoffmann, G. W.
1999-01-01
We report on new measurements of the spin-dependent neutron-proton total cross-section differences in longitudinal and transverse geometries (Δσ L and Δσ T respectively) and between 5 and 20 MeV. These transmission experiments involve a polarized neutron beam and polarized proton target. The polarized neutron beam was produced as a secondary beam via charged-particle induced neutron-production reactions. The proton target was cryogenically cooled and dynamically polarized. These data will be used to extract ε 1 , the phase-shift parameter which characterizes the strength of the tensor interaction at low energy
Impurity-induced tuning of quantum-well States in spin-dependent resonant tunneling.
Kalitsov, Alan; Coho, A; Kioussis, Nicholas; Vedyayev, Anatoly; Chshiev, M; Granovsky, A
2004-07-23
We report exact model calculations of the spin-dependent tunneling in double magnetic tunnel junctions in the presence of impurities in the well. We show that the impurity can tune selectively the spin channels giving rise to a wide variety of interesting and novel transport phenomena. The tunneling magnetoresistance, the spin polarization, and the local current can be dramatically enhanced or suppressed by impurities. The underlying mechanism is the impurity-induced shift of the quantum well states (QWSs), which depends on the impurity potential, impurity position, and the symmetry of the QWS. Copyright 2004 The American Physical Society
Spin-dependent Hall effect in degenerate semiconductors: a theoretical study
International Nuclear Information System (INIS)
Idrish Miah, M
2008-01-01
The spin-dependent Hall (SDH) effect in degenerate semiconductors is investigated theoretically. Starting from a two-component drift-diffusion equation, an expression for SDH voltage (V SDH ) is derived, and drift and diffusive contributions to V SDH are studied. For the possible enhancement of the diffusive part, degenerate and nondegenerate cases are examined. We find that due to an increase in the diffusion coefficient V SDH increases in a degenerate semiconductor, consistent with the experimental observations. The expression for V SDH is reduced in three limiting cases, namely diffusive, drift-diffusion crossover and drift, and is analysed. The results agree with those obtained in recent theoretical investigations.
Goldstein, G R
2001-01-01
Spin dependent fragmentation functions for heavy flavor quarks to fragment into heavy baryons are calculated in a quark-diquark model. The production of intermediate spin 1/2 and 3/2 excited states is explicity included. $\\Lambda_b$ , $\\Lambda_c$ and $\\Xi_c$ production rate and polarization at LEP energies are calculated and, where possible, compared with experiment. A different approach, also relying on a heavy quark-diquark model, is proposed for the small momentum transfer inclusive production of polarized heavy flavor hyperons. The predicted $\\Lambda_c$ polarization is roughly in agreement with experiment.
International Nuclear Information System (INIS)
Kartavtsev, O.I.; Malykh, A.V.; Sofianos, S.A.
2008-01-01
The universal three-body dynamics in ultracold binary gases confined to one-dimensional motion is studied. The three-body binding energies and the (2+1)-scattering lengths are calculated for two identical particles of mass m and a different one of mass m 1 , between which interactions are described in the low-energy limit by zero-range potentials. The critical values of the mass ratio m/m 1 , at which the three-body states arise and the (2+1)-scattering length equals zero, are determined both for zero and infinite interaction strength λ 1 of the identical particles. A number of exact results are enlisted and asymptotic dependences both for m/m 1 → infinity and λ 1 → -infinity are derived. Combining the numerical and analytical results, a schematic diagram showing the number of the three-body bound states and the sign of the (2+1)-scattering length in the plane of the mass ratio and interaction-strength ratio is deduced. The results provide a description of the homogeneous and mixed phases of atoms and molecules in dilute binary quantum gases
Spin dependent transport of hot electrons through ultrathin epitaxial metallic films
Energy Technology Data Exchange (ETDEWEB)
Heindl, Emanuel
2010-06-23
In this work relaxation and transport of hot electrons in thin single crystalline metallic films is investigated by Ballistic Electron Emission Microscopy. The electron mean free paths are determined in an energy interval of 1 to 2 eV above the Fermi level. While fcc Au-films appear to be quite transmissive for hot electrons, the scattering lengths are much shorter for the ferromagnetic alloy FeCo revealing, furthermore, a strong spin asymmetry in hot electron transport. Additional information is gained from temperature dependent studies in combination with golden rule approaches in order to disentangle the impact of several relaxation and transport properties. It is found that bcc Fe-films are much less effective in spin filtering than films made of the FeCo-alloy. (orig.)
Haddock, C.; Crawford, B.; Fox, W.; Francis, I.; Holley, A.; Magers, S.; Sarsour, M.; Snow, W. M.; Vanderwerp, J.
2018-03-01
We discuss the design and construction of a novel target array of nonmagnetic test masses used in a neutron polarimetry measurement made in search for new possible exotic spin dependent neutron-atominteractions of Nature at sub-mm length scales. This target was designed to accept and efficiently transmit a transversely polarized slow neutron beam through a series of long open parallel slots bounded by flat rectangular plates. These openings possessed equal atom density gradients normal to the slots from the flat test masses with dimensions optimized to achieve maximum sensitivity to an exotic spin-dependent interaction from vector boson exchanges with ranges in the mm - μm regime. The parallel slots were oriented differently in four quadrants that can be rotated about the neutron beam axis in discrete 90°increments using a Geneva drive. The spin rotation signals from the 4 quadrants were measured using a segmented neutron ion chamber to suppress possible systematic errors from stray magnetic fields in the target region. We discuss the per-neutron sensitivity of the target to the exotic interaction, the design constraints, the potential sources of systematic errors which could be present in this design, and our estimate of the achievable sensitivity using this method.
Spin dependence in the neutralization of He+ ions in metals: An analysis of different contributions
International Nuclear Information System (INIS)
Alducin, M.
2005-01-01
We study the spin polarization of the Auger electrons produced during the neutralization of He + ions in a free electron gas. In this process, one metal electron decays to the unoccupied state and a second electron is promoted to a continuum excited state. Although the spin of the decaying electron is fixed, both spins are allowed for the excited one. The states of the electrons involved in this Auger capture process are described by the spin-dependent Kohn-Sham orbitals obtained from density functional theory and the local spin approximation. The Auger capture rates indicate a strong polarization of the excited electron. In a paramagnetic free electron gas, there are two mechanisms accounting for this effect, the spin-dependent screening and the interference between indistinguishable processes when the involved electrons are in the same spin state. In a spin-polarized medium, the difference in the density of spin-up and spin-down electrons is a new ingredient to be considered. As a result, the excited electrons preferably come from the majority band, even in the case of He + ions with spin opposite to that of the majority band embedded in a low spin-polarized free electron gas
Spin-dependent tunneling recombination in heterostructures with a magnetic layer
Energy Technology Data Exchange (ETDEWEB)
Denisov, K. S., E-mail: denisokonstantin@gmail.com; Rozhansky, I. V.; Averkiev, N. S. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Lähderanta, E. [Lappeenranta University of Technology (Finland)
2017-01-15
We propose a mechanism for the generation of spin polarization in semiconductor heterostructures with a quantum well and a magnetic impurity layer spatially separated from it. The spin polarization of carriers in a quantum well originates from spin-dependent tunneling recombination at impurity states in the magnetic layer, which is accompanied by a fast linear increase in the degree of circular polarization of photoluminescence from the quantum well. Two situations are theoretically considered. In the first case, resonant tunneling to the spin-split sublevels of the impurity center occurs and spin polarization is caused by different populations of resonance levels in the quantum well for opposite spin projections. In the second, nonresonant case, the spin-split impurity level lies above the occupied states of electrons in the quantum well and plays the role of an intermediate state in the two-stage coherent spin-dependent recombination of an electron from the quantum well and a hole in the impurity layer. The developed theory allows us to explain both qualitatively and quantitatively the kinetics of photoexcited electrons in experiments with photoluminescence with time resolution in Mn-doped InGaAs heterostructures.
Spin-dependent delay time and Hartman effect in asymmetrical graphene barrier under strain
Sattari, Farhad; Mirershadi, Soghra
2018-01-01
We study the spin-dependent tunneling time, including group delay and dwell time, in a graphene based asymmetrical barrier with Rashba spin-orbit interaction in the presence of strain, sandwiched between two normal leads. We find that the spin-dependent tunneling time can be efficiently tuned by the barrier width, and the bias voltage. Moreover, for the zigzag direction strain although the oscillation period of the dwell time does not change, the oscillation amplitude increases by increasing the incident electron angle. It is found that for the armchair direction strain unlike the zigzag direction the group delay time at the normal incidence depends on the spin state of electrons and Hartman effect can be observed. In addition, for the armchair direction strain the spin polarization increases with increasing the RSOI strength and the bias voltage. The magnitude and sign of spin polarization can be manipulated by strain. In particular, by applying an external electric field the efficiency of the spin polarization is improved significantly in strained graphene, and a fully spin-polarized current is generated.
Energy Technology Data Exchange (ETDEWEB)
Sanchez-Barriga, Jaime; Varykhalov, Andrei; Fink, Joerg; Rader, Oliver; Duerr, Hermann; Eberhardt, Wolfgang [Bessy GmbH, Berlin (Germany)
2008-07-01
Spin dependent low-energy electronic excitations in 3d ferromagnets are of special interest due to the need of a microscopic understanding of the electronic structure of solids. Low-energy electrons (or holes) become dressed by a cloud of excitations resulting in quasiparticles of a finite lifetime and a different effective mass. These type of excitations have been studied by many theoretical methods, and it has been found that because of many body effects no sharp quasiparticle peaks exist for binding energies larger than 2 eV. Interestingly, it has been shown that strong correlation effects could particularly affect majority spin electrons, leading to a pronounced damping of quasiparticles at binding energies around 2 eV and above. In order to give an experimental corroboration to these findings, we have performed a systematic study of the spin-dependent quasiparticle lifetime and band structure of ferromagnetic 3d transition metal surfaces by means of spin and angle-resolved photoemission spectroscopy. On hcp Co(0001), fcc Ni(111) and bcc Fe(110), we have found a more pronounced renormalization of the majority spin quasiparticle spectral weight going from Ni to Co which are both strong ferromagnets. For Fe, a weak ferromagnet, such a process becomes more prominent in the minority channel.
Fotoohi, Somayeh; Haji-Nasiri, Saeed
2018-04-01
Spin-dependent electronic transport properties of single 3d transition metal (TM) atoms doped α-armchair graphyne nanoribbons (α-AGyNR) are investigated by non-equilibrium Green's function (NEGF) method combined with density functional theory (DFT). It is found that all of the impurity atoms considered in this study (Fe, Co, Ni) prefer to occupy the sp-hybridized C atom site in α-AGyNR, and the obtained structures remain planar. The results show that highly localized impurity states are appeared around the Fermi level which correspond to the 3d orbitals of TM atoms, as can be derived from the projected density of states (PDOS). Moreover, Fe, Co, and Ni doped α-AGyNRs exhibit magnetic properties due to the strong spin splitting property of the energy levels. Also for each case, the calculated current-voltage characteristic per super-cell shows that the spin degeneracy in the system is obviously broken and the current becomes strongly spin dependent. Furthermore, a high spin-filtering effect around 90% is found under the certain bias voltages in Ni doped α-AGyNR. Additionally, the structure with Ni impurity reveals transfer characteristic that is suitable for designing a spin current switch. Our findings provide a high possibility to design the next generation spin nanodevices with novel functionalities.
Energy Technology Data Exchange (ETDEWEB)
Tikhomirov, Victor V. [Belarusian State University, Institute for Nuclear Problems, Minsk (Belarus)
2017-07-15
A refined equation for channeling particle diffusion in transverse energy taking into consideration large-angle scattering by nuclei is suggested. This equation is reduced to the Sturm-Liouville problem, allowing one to reveal both the origin and the limitations of the dechanneling length notion. The values of the latter are evaluated for both positively and negatively charged particles of various energies. New features of the dechanneling dynamics of positively charged particles are also revealed. First, it is demonstrated that the dechanneling length notion is completely inapplicable for their nuclear dechanneling process. Second, the effective electron dechanneling length of positively charged particle varies more than twice converging to a constant asymptotic value only at the depth exceeding the latter. (orig.)
How to realize a spin-dependent Seebeck diode effect in metallic zigzag γ-graphyne nanoribbons?
Wu, Dan-Dan; Liu, Qing-Bo; Fu, Hua-Hua; Wu, Ruqian
2017-11-30
The spin-dependent Seebeck effect (SDSE) is one of the core topics of spin caloritronics. In the traditional device designs of spin-dependent Seebeck rectifiers and diodes, finite spin-dependent band gaps of materials are required to realize the on-off characteristic in thermal spin currents, and nearly zero charge current should be achieved to reduce energy dissipation. Here, we propose that two ferromagnetic zigzag γ-graphyne nanoribbons (ZγGNRs) without any spin-dependent band gaps around the Fermi level can not only exhibit the SDSE, but also display rectifier and diode effects in thermal spin currents characterized by threshold temperatures, which originates from the compensation effect occurring in spin-dependent transmissions but not from the spin-splitting band gaps in materials. The metallic characteristics of ZγGNRs bring about an advantage that the gate voltage is an effective route to adjust the symmetry of spin-splitting bands to obtain pure thermal spin currents. The results provide a new mechanism to realize spin-Seebeck rectifier and diode effects in 2D materials and expand material candidates towards spin-Seebeck device applications.
Spin-dependent recombination involving oxygen-vacancy complexes in silicon
Franke, David P.; Hoehne, Felix; Vlasenko, Leonid S.; Itoh, Kohei M.; Brandt, Martin S.
2014-05-01
Spin-dependent relaxation and recombination processes in γ-irradiated n-type Czochralski-grown silicon are studied using continuous wave (cw) and pulsed electrically detected magnetic resonance (EDMR). Two processes involving the SL1 center, the neutral excited triplet state of the oxygen-vacancy complex, are observed which can be separated by their different dynamics. One of the processes is the relaxation of the excited SL1 state to the ground state of the oxygen-vacancy complex, the other a charge transfer between 31P donors and SL1 centers forming close pairs, as indicated by electrically detected electron double resonance. For both processes, the recombination dynamics is studied with pulsed EDMR techniques. We demonstrate the feasibility of true zero-field cw and pulsed EDMR for spin-1 systems and use this to measure the lifetimes of the different spin states of SL1 also at vanishing external magnetic field.
Spin-dependent Hall effect in degenerate semiconductors: a theoretical study
Energy Technology Data Exchange (ETDEWEB)
Idrish Miah, M [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)], E-mail: m.miah@griffith.edu.au
2008-10-15
The spin-dependent Hall (SDH) effect in degenerate semiconductors is investigated theoretically. Starting from a two-component drift-diffusion equation, an expression for SDH voltage (V{sub SDH}) is derived, and drift and diffusive contributions to V{sub SDH} are studied. For the possible enhancement of the diffusive part, degenerate and nondegenerate cases are examined. We find that due to an increase in the diffusion coefficient V{sub SDH} increases in a degenerate semiconductor, consistent with the experimental observations. The expression for V{sub SDH} is reduced in three limiting cases, namely diffusive, drift-diffusion crossover and drift, and is analysed. The results agree with those obtained in recent theoretical investigations.
Solvable model of spin-dependent transport through a finite array of quantum dots
International Nuclear Information System (INIS)
Avdonin, S A; Dmitrieva, L A; Kuperin, Yu A; Sartan, V V
2005-01-01
The problem of spin-dependent transport of electrons through a finite array of quantum dots attached to a 1D quantum wire (spin gun) for various semiconductor materials is studied. The Breit-Fermi term for spin-spin interaction in the effective Hamiltonian of the device is shown to result in a dependence of transmission coefficient on the spin orientation. The difference of transmission probabilities for singlet and triplet channels can reach a few per cent for a single quantum dot. For several quantum dots in the array due to interference effects it can reach approximately 100% for some energy intervals. For the same energy intervals the conductance of the device reaches the value ∼1 in [e 2 /πℎ] units. As a result a model of the spin gun which transforms the spin-unpolarized electron beam into a completely polarized one is suggested
Spin-dependent heat and thermoelectric currents in a Rashba ring coupled to a photon cavity
Abdullah, Nzar Rauf; Tang, Chi-Shung; Manolescu, Andrei; Gudmundsson, Vidar
2018-01-01
Spin-dependent heat and thermoelectric currents in a quantum ring with Rashba spin-orbit interaction placed in a photon cavity are theoretically calculated. The quantum ring is coupled to two external leads with different temperatures. In a resonant regime, with the ring structure in resonance with the photon field, the heat and the thermoelectric currents can be controlled by the Rashba spin-orbit interaction. The heat current is suppressed in the presence of the photon field due to contribution of the two-electron and photon replica states to the transport while the thermoelectric current is not sensitive to changes in parameters of the photon field. Our study opens a possibility to use the proposed interferometric device as a tunable heat current generator in the cavity photon field.
Controlling spin-dependent tunneling by bandgap tuning in epitaxial rocksalt MgZnO films.
Li, D L; Ma, Q L; Wang, S G; Ward, R C C; Hesjedal, T; Zhang, X-G; Kohn, A; Amsellem, E; Yang, G; Liu, J L; Jiang, J; Wei, H X; Han, X F
2014-12-02
Widespread application of magnetic tunnel junctions (MTJs) for information storage has so far been limited by the complicated interplay between tunnel magnetoresistance (TMR) ratio and the product of resistance and junction area (RA). An intricate connection exists between TMR ratio, RA value and the bandgap and crystal structure of the barrier, a connection that must be unravelled to optimise device performance and enable further applications to be developed. Here, we demonstrate a novel method to tailor the bandgap of an ultrathin, epitaxial Zn-doped MgO tunnel barrier with rocksalt structure. This structure is attractive due to its good Δ1 spin filtering effect, and we show that MTJs based on tunable MgZnO barriers allow effective balancing of TMR ratio and RA value. In this way spin-dependent transport properties can be controlled, a key challenge for the development of spintronic devices.
Spin-dependent recombination processes in wide band gap II-Mn-VI compounds
International Nuclear Information System (INIS)
Godlewski, M.; Yatsunenko, S.; Khachapuridze, A.; Ivanov, V.Yu.
2004-01-01
Mechanisms of optical detection of magnetic resonance in wide band gap II-Mn-VI diluted magnetic semiconductor (DMS) are discussed based on the results of photoluminescence (PL), PL kinetics, electron spin resonance (ESR) and optically detected magnetic resonance (ODMR) and optically detected cyclotron resonance (ODCR) investigations. Spin-dependent interactions between localized spins of Mn 2+ ions and spins/magnetic moments of free, localized or bound carriers are responsible for the observed ODMR signals. We conclude that these interactions are responsible for the observed rapid shortening of the PL decay time of 4 T 1 → 6 A 1 intra-shell emission of Mn 2+ ions and also for the observed delocalization of excitons in low dimensional structures
Relativistic description of quark-antiquark bound states. II. Spin-dependent treatment
International Nuclear Information System (INIS)
Gara, A.; Durand, B.; Durand, L.
1990-01-01
We present the results of a study of light- and heavy-quark--antiquark bound states in the context of the reduced Bethe-Salpeter equation, including the full spin dependence. We obtain good fits to the observed spin splittings in the b bar b and c bar c systems using a short-distance single-gluon-exchange interaction, and a long-distance scalar confining interaction. However, we cannot obtain satisfactory fits to the centers of gravity of the b bar b and c bar c spin multiplets at the same time, and the splittings calculated for q bar Q mesons containing the lighter quarks are very poor. The difficulty appears to be intrinsic to the reduced Salpeter equation for reasons which we discuss
International Nuclear Information System (INIS)
Popescu, Voicu; Ebert, Hubert; Papanikolaou, Nikolaos; Zeller, Rudolf; Dederichs, Peter H
2004-01-01
We present a fully relativistic generalization of the Landauer-Buettiker formalism that has been implemented within the framework of the spin-polarized relativistic screened Korringa-Kohn-Rostoker Green function method. This approach, going beyond the two-current model, supplies a more general description of the electronic transport. It is shown that the relativistic conductance can be split in terms of individual spin-diagonal and spin-off-diagonal (spin-flip) components, which allows a detailed analysis of the influence of spin-orbit-coupling-induced spin-flip processes on the spin-dependent transport. We apply our method to calculate the ballistic conductance in Fe/GaAs/Fe magnetic tunnel junctions. We find that, by removing the spin selection rules, the spin-orbit coupling strongly influences the conductance, not only qualitatively but also quantitatively, especially in the anti-parallel alignment of the magnetization in the two Fe leads
Spin-dependent transport and functional design in organic ferromagnetic devices
Directory of Open Access Journals (Sweden)
Guichao Hu
2017-09-01
Full Text Available Organic ferromagnets are intriguing materials in that they combine ferromagnetic and organic properties. Although challenges in their synthesis still remain, the development of organic spintronics has triggered strong interest in high-performance organic ferromagnetic devices. This review first introduces our theory for spin-dependent electron transport through organic ferromagnetic devices, which combines an extended Su–Schrieffer–Heeger model with the Green’s function method. The effects of the intrinsic interactions in the organic ferromagnets, including strong electron–lattice interaction and spin–spin correlation between π-electrons and radicals, are highlighted. Several interesting functional designs of organic ferromagnetic devices are discussed, specifically the concepts of a spin filter, multi-state magnetoresistance, and spin-current rectification. The mechanism of each phenomenon is explained by transmission and orbital analysis. These works show that organic ferromagnets are promising components for spintronic devices that deserve to be designed and examined in future experiments.
A lattice calculation of the nucleon's spin-dependent structure function g2 revisited
International Nuclear Information System (INIS)
Goeckeler, M.; Rakow, P.E.L.; Schaefer, A.; Schierholz, G.
2000-11-01
Our previous calculation of the spin-dependent structure function g 2 is revisited. The interest in this structure function is to a great extent motivated by the fact that it receives contributions from twist-two as well as from twist-three operators already in leading order of 1/Q 2 thus offering the unique possibility of directly assessing higher-twist effects. In our former calculation the lattice operators were renormalized perturbatively and mixing with lower-dimensional operators was ignored. However, the twist-three operator which gives rise to the matrix element d 2 mixes non-perturbatively with an operator of lower dimension. Taking this effect into account leads to a considerably smaller value of d 2 , which is consistent with the experimental data. (orig.)
International Nuclear Information System (INIS)
Xi, L.; Du, J.H.; Ma, J.H.; Wang, Z.; Zuo, Y.L.; Xue, D.S.
2013-01-01
Highlights: ► Spin-dependent transport property of LSMO/oleic acid nanoparticles is investigated. ► Transport properties and MR measured by Cu/nanoparticle assembly/elargol device. ► Non-linear I–V curve indicates a tunneling type transport properties. ► Tunnel barrier height around 1.3 ± 0.15 eV was obtained by fitting I–V curves. ► LFMR of LSMO/oleic acid molecules value reaches −18% with current of 0.1 μA at 10 K. - Abstract: Spin-dependent transport property through molecules is investigated using a monolayer of oleic acid molecule self-assembled half metallic La 0.7 Sr 0.3 MnO 3 (LSMO) nanoparticles, which was synthesized using a coprecipitation method. Fourier transform infrared spectroscopy was used to confirm that one-monolayer oleic acid molecules chemically bond to the LSMO nanoparticles. The transport properties and magnetoresistance (MR) effect of the oleic acid molecule coated LSMO nanoparticles were measured by a direct current four probes method using a Cu/nanoparticle assembly/elargol electrode sandwich device with various temperatures and bias voltages. The non-linear I–V curve indicates a tunneling type transport properties. The tunnel barrier height around 1.3 ± 0.15 eV was obtained by fitting the I–V curve according to the Simmons equation. The magnetoresistance curves can be divided to high-field MR and low-field MR (LFMR) parts. The former is ascribed to the influence of spin disorder or canting within the LSMO nanoparticle surface and the latter one with strong bias dependence is attributed to the spin-dependent tunneling effect through the insulating surface layer of LSMO and oleic acid molecules. The enhanced LFMR effect for oleic acid coated LSMO with respect to the bare LSMO was attributed to the enhanced tunneling transport and weak spin scattering in oleic acid molecule barrier.
International Nuclear Information System (INIS)
Dorokhov, A.E.; Kochelev, N.I.
1991-01-01
Within the model of QCD vacuum as an instanton liquid the spin-dependent structure functions of sea quarks are obtained. It is shown that the EMC data manages the definition of new Regge trajectory connected with the axial anomaly. The model explains the modern experimental data on the sea quark structure functions. 23 refs.; 3 figs
Summary of measurements of the spin dependence in NN interactions from 2 to 12 GeV/c
International Nuclear Information System (INIS)
Rust, D.R.
1975-01-01
The status of experimental measurements of the spin dependence in NN interactions from 2 to 12 GeV/c as of June 1975 is summarized. Older data have been left out if more accurate or more complete results are available
Edge-defect induced spin-dependent Seebeck effect and spin figure of merit in graphene nanoribbons.
Liu, Qing-Bo; Wu, Dan-Dan; Fu, Hua-Hua
2017-10-11
By using the first-principle calculations combined with the non-equilibrium Green's function approach, we have studied spin caloritronic properties of graphene nanoribbons (GNRs) with different edge defects. The theoretical results show that the edge-defected GNRs with sawtooth shapes can exhibit spin-dependent currents with opposite flowing directions by applying temperature gradients, indicating the occurrence of the spin-dependent Seebeck effect (SDSE). The edge defects bring about two opposite effects on the thermal spin currents: the enhancement of the symmetry of thermal spin-dependent currents, which contributes to the realization of pure thermal spin currents, and the decreasing of the spin thermoelectric conversion efficiency of the devices. It is fortunate that applying a gate voltage is an efficient route to optimize these two opposite spin thermoelectric properties towards realistic device applications. Moreover, due to the existence of spin-splitting band gaps, the edge-defected GNRs can be designed as spin-dependent Seebeck diodes and rectifiers, indicating that the edge-defected GNRs are potential candidates for room-temperature spin caloritronic devices.
DEFF Research Database (Denmark)
Sivaramakrishnan, S.; Sung, J.; Ali, M.
2009-01-01
as a force transducer, rigid spacer, or flexible linker in proteins. In this study, we quantity this flexibility in terms of persistence length, namely the length scale over which it is rigid. We use single-molecule optical trapping and small-angle x-ray scattering, combined with Monte Carlo simulations...
Energy Technology Data Exchange (ETDEWEB)
Granovsky, Alexander [Faculty of Physics, Lomonosov Moscow State University, Moscow 119992 (Russian Federation)]. E-mail: granov@magn.ru; Kozlov, Andrey [Faculty of Physics, Lomonosov Moscow State University, Moscow 119992 (Russian Federation); Nedukh, Sergey [Institute of Radiophysics and Electronics NAS of Ukraine, Kharkov 61085 (Ukraine); Tarapov, Sergey [Institute of Radiophysics and Electronics NAS of Ukraine, Kharkov 61085 (Ukraine)
2005-07-15
Since the dielectric permittivity is linear with frequency-dependent conductivity, high-frequency properties for any kind of magnetic materials with the high magnetoresistance depend on magnetization. It manifests as magnetorefractive effect (MRE) in the infrared region of spectrum and as magnetoimpedance (MI) in the frequency range between radio and microwaves. The main mechanism of both MRE and MI in nanocomposites with tunnel-type magnetoresistance is high-frequency spin-dependent tunnelling. We report on recent results of theoretical and experimental investigations of MRE and MI in nanocomposites Co{sub 51.5}Al{sub 19.5}O{sub 29}, Co{sub 50.2}Ti{sub 9.1}O{sub 40.7}, Co{sub 52.3}Si{sub 12.2}O{sub 35.5} and (Co{sub 0,4}Fe{sub 0,6}){sub 48}(MgF){sub 52}. Most of the obtained experimental data for MRE and MI are consistent with the theory based on considering the tunnel junction between adjacent granules in percolation cluster as a capacitor.
Altuntaş, Emine; Ammon, Jeffrey; Cahn, Sidney B.; DeMille, David
2018-04-01
Nuclear-spin-dependent parity violation (NSD-PV) effects in atoms and molecules arise from Z0 boson exchange between electrons and the nucleus and from the magnetic interaction between electrons and the parity-violating nuclear anapole moment. It has been proposed to study NSD-PV effects using an enhancement of the observable effect in diatomic molecules [D. DeMille et al., Phys. Rev. Lett. 100, 023003 (2008), 10.1103/PhysRevLett.100.023003]. Here we demonstrate highly sensitive measurements of this type, using the test system 138Ba19F. We show that systematic errors associated with our technique can be suppressed to at least the level of the present statistical sensitivity. With ˜170 h of data, we measure the matrix element W of the NSD-PV interaction with uncertainty δ W /(2 π )<0.7 Hz for each of two configurations where W must have different signs. This sensitivity would be sufficient to measure NSD-PV effects of the size anticipated across a wide range of nuclei.
Spin dependent disorder in a junction device with spin orbit couplings
International Nuclear Information System (INIS)
Ganguly, Sudin; Basu, Saurabh
2016-01-01
Using the multi-probe Landauer-BUttiker formula and Green's function approach, we calculate the longitudinal conductance (LC) and spin Hall conductance (SHC) numerically in a two-dimensional junction system with the Rashba and Dresselhaus spin orbit coupling (SOC) and spin dependent disorder (SDD) in presence of both random onsite and hopping disorder strengths. It has been found that when the strengths of the RSOC and DSOC are same, the SHC vanishes. Further in presence of random onsite or hopping disorder, the SHC is still zero when the strengths of the two types of SOC, that is Rashba and Dressselhaus are the same. This indicates that the cancellation of SHC is robust even in the presence of random disorder. Only with the inclusion of SDD (onsite or hopping), a non-zero SHC is found and it increases as the strength of SDD increases. The physical implication of the existence of a non-zero SHC has been explored in this work. Finally, we have compared the effect of onsite SDD and hopping SDD on both longitudinal and spin Hall conductances. (paper)
Equations of motion of test particles for solving the spin-dependent Boltzmann–Vlasov equation
Energy Technology Data Exchange (ETDEWEB)
Xia, Yin [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); University of Chinese Academy of Science, Beijing 100049 (China); Xu, Jun, E-mail: xujun@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Bao-An [Department of Physics and Astronomy, Texas A& M University-Commerce, Commerce, TX 75429-3011 (United States); Department of Applied Physics, Xi' an Jiao Tong University, Xi' an 710049 (China); Shen, Wen-Qing [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)
2016-08-10
A consistent derivation of the equations of motion (EOMs) of test particles for solving the spin-dependent Boltzmann–Vlasov equation is presented. The resulting EOMs in phase space are similar to the canonical equations in Hamiltonian dynamics, and the EOM of spin is the same as that in the Heisenburg picture of quantum mechanics. Considering further the quantum nature of spin and choosing the direction of total angular momentum in heavy-ion reactions as a reference of measuring nucleon spin, the EOMs of spin-up and spin-down nucleons are given separately. The key elements affecting the spin dynamics in heavy-ion collisions are identified. The resulting EOMs provide a solid foundation for using the test-particle approach in studying spin dynamics in heavy-ion collisions at intermediate energies. Future comparisons of model simulations with experimental data will help to constrain the poorly known in-medium nucleon spin–orbit coupling relevant for understanding properties of rare isotopes and their astrophysical impacts.
Demonstration of a Sensitive Method to Measure Nuclear-Spin-Dependent Parity Violation
Altuntaş, Emine; Ammon, Jeffrey; Cahn, Sidney B.; DeMille, David
2018-04-01
Nuclear-spin-dependent parity violation (NSD-PV) effects in atoms and molecules arise from Z0 boson exchange between electrons and the nucleus, and from the magnetic interaction between electrons and the parity-violating nuclear anapole moment. We demonstrate measurements of NSD-PV that use an enhancement of the effect in diatomic molecules, here using the test system 138Ba 19. Our sensitivity surpasses that of any previous atomic parity violation measurement. We show that systematic errors can be suppressed to at least the level of the present statistical sensitivity. We measure the matrix element W of the NSD-PV interaction with total uncertainty δ W /(2 π )<0.7 Hz , for each of two configurations where W must have different signs. This sensitivity would be sufficient to measure NSD-PV effects of the size anticipated across a wide range of nuclei including 137Ba in 137BaF, where |W |/(2 π )≈5 Hz is expected.
International Nuclear Information System (INIS)
Liang, Z.X.; Zhang, Z.D.; Liu, W.M.
2005-01-01
We present a family of exact solutions of the one-dimensional nonlinear Schroedinger equation which describes the dynamics of a bright soliton in Bose-Einstein condensates with the time-dependent interatomic interaction in an expulsive parabolic potential. Our results show that, under a safe range of parameters, the bright soliton can be compressed into very high local matter densities by increasing the absolute value of the atomic scattering length, which can provide an experimental tool for investigating the range of validity of the one-dimensional Gross-Pitaevskii equation. We also find that the number of atoms in the bright soliton keeps dynamic stability: a time-periodic atomic exchange is formed between the bright soliton and the background
Batley, J R; Kalmus, G; Lazzeroni, C; Munday, D J; Slater, M W; Wotton, S A; Arcidiacono, R; Bocquet, G; Cabibbo, N; Ceccucci, A; Cundy, D; Falaleev, V; Fidecaro, Maria; Gatignon, L; Gonidec, A; Kubischta, W; Norton, A; Maier, A; Patel, M; Peters, A; Balev, S; Frabetti, P L; Goudzovski, E; Khristov, P Z; Kekelidze, V; Kozhuharov, V; Litov, L; Madigozhin, D T; Marinova, E; Molokanova, N; Polenkevich, I; Potrebenikov, Yu; Stoynev, S; Zinchenko, A; Monnier, E; Swallow, E; Winston, R; Rubin, P; Walker, A; Baldini, W; Cotta-Ramusino, A; Dalpiaz, P; Damiani, C; Fiorini, M; Gianoli, A; Martini, M; Petrucci, F; Savrié, M; Scarpa, M; Wahl, H; Calvetti, M; Iacopini, E; Ruggiero, G; Bizzeti, A; Lenti, M; Veltri, M; Behler, M; Eppard, K; Kleinknecht, K; Marouelli, P; Masetti, L; Moosbrugger, U; Morales-Morales, C; Renk, B; Wache, M; Wanke, R; Winhart, A; Coward, D; Dabrowski, A; Fonseca-Martin, T; Shieh, M; Szleper, M; Velasco, M; Wood, M D; Anzivino, G; Imbergamo, E; Nappi, A; Piccini, M; Raggi, M; Valdata-Nappi, M; Cenci, P; Pepé, M; Pettrucci, M C; Cerri, C; Fantechi, R; Collazuol, G; Di Lella, L; Lamanna, G; Mannelli, I; Michetti, A; Costantini, F; Doble, N; Fiorini, L; Giudici, S; Pierazzini, G; Sozzi, M; Venditti, S; Bloch-Devaux, B; Cheshkov, C; Chèze, J B; De Beer, M; Derré, J; Marel, G; Mazzucato, E; Peyaud, B; Vallage, B; Holder, M; Ziolkowski, M; Bifani, S; Biino, C; Cartiglia, N; Marchetto, F; Bifani, S; Clemencic, M; Goy-Lopez, S; Dibon, H; Jeitler, M; Markytan, M; Mikulec, I; Neuhofer, G; Widhalm, L
2009-01-01
We report the results from a study of the full sample of $~6.031 x 10^{7} K^{\\pm} \\to \\pi^{\\pm} \\pi^{0} \\pi^{0}$ decays recorded by the NA48/2 experiment at the CERN SPS. As first observed in this experiment, the $\\pi^{0} \\pi^{0}$ invariant mass (M_00) distribution shows a cusp-like anomaly in the region around $M_{00} = 2m_{+}$, where m_{+} is the charged pion mass. This anomaly has been interpreted as an effect due mainly to the final state charge exchange scattering process $\\pi^{+}\\pi^{-} \\to \\pi^{0} \\pi^{0}$ in $K^{\\pm} \\to \\pi^{\\pm} \\pi^{+} \\pi^{-}$ decay. Fits to the M_{00} distribution using two different theoretical models provide the presently most precise determination of $a_{0}-a_{2}$, the difference between the pi pi S-wave scattering lengths in the isospin I = 0 and I = 2 states. Higher-order pi pi rescattering terms, included in the two models, allow also an independent, though less precise, determination of a_2.
Radiation tolerance of a spin-dependent tunnelling magnetometer for space applications
International Nuclear Information System (INIS)
Persson, Anders; Thornell, Greger; Nguyen, Hugo
2011-01-01
To meet the increasing demand for miniaturized space instruments, efforts have been made to miniaturize traditional magnetometers, e.g. fluxgate and spin-exchange relaxation-free magnetometers. These have, for different reasons, turned out to be difficult. New technologies are needed, and promising in this respect are tunnelling magnetoresistive (TMR) magnetometers, which are based on thin film technology. However, all new space devices first have to be qualified, particularly in terms of radiation resistance. A study on TMR magnetometers' vulnerability to radiation is crucial, considering the fact that they employ a dielectric barrier, which can be susceptible to charge trapping from ionizing radiation. Here, a TMR-based magnetometer, called the spin-dependent tunnelling magnetometer (SDTM), is presented. A magnetometer chip consisting of three Wheatstone bridges, with an angular pitch of 120°, was fabricated using microstructure technology. Each branch of the Wheatstone bridges consists of eight pairs of magnetic tunnel junctions (MTJs) connected in series. Two such chips are used to measure the three-dimensional magnetic field vector. To investigate the SDTM's resistance to radiation, one branch of a Wheatstone bridge was irradiated with gamma rays from a Co 60 source with a dose rate of 10.9 rad min −1 to a total dose of 100 krad. The TMR of the branch was monitored in situ, and the easy axis TMR loop and low-frequency noise characteristics of a single MTJ were acquired before and after irradiation with the total dose. It was concluded that radiation did not influence the MTJs in any noticeable way in terms of the TMR ratio, coercivity, magnetostatic coupling or low-frequency noise
International Nuclear Information System (INIS)
Agamalian, M.M.; Alamo, R.G.; Londono, J.D.; Mandelkern, L.; Wignall, G.D.
1999-01-01
SANS experiments on blends of linear, high density (HD) and long chain branched, low density (LD) polyethylenes indicate that these systems form a one-phase mixture in the melt. However, the maximum spatial resolution of pinhole cameras is approximately equal to 10 3 and it has therefore been suggested that data might also be interpreted as arising from a bi-phasic melt with large a particle size ( 1 m), because most of the scattering from the different phases would not be resolved. We have addressed this hypothesis by means of USANS experiments, which confirm that HDPEILDPE blends are homogenous in the melt on length scales up to 20 m. We have also studied blends of HDPE and short-chain branched linear low density polyethylenes (LLDPEs), which phase separate when the branch content is sufficiently high. LLDPEs prepared with Ziegler-Natta catalysts exhibit a wide distribution of compositions, and may therefore be thought of as a blend of different species. When the composition distribution is broad enough, a fraction of highly branched chains may phase separate on m-length scales, and USANS has also been used to quantify this phenomenon
Spin-dependent Goos–Hänchen shift and spin beam splitter in gate-controllable ferromagnetic graphene
International Nuclear Information System (INIS)
Wang, Y.; Liu, Y.; Wang, B.
2014-01-01
The transmission and Goos–Hänchen (GH) shift for charge carriers in gate-controllable ferromagnetic graphene induced by ferromagnetic insulator are investigated theoretically. Numerical results demonstrate that spin-up and spin-down electrons exhibit remarkably different transmission and GH shifts. The spin-dependent GH shifts directly demonstrate the spin beam splitting effect, which can be controlled by the voltage of gate. We attribute the spin beam splitting effect to the combination of tunneling through potential barrier and Zeeman interaction from the magnetic field and the exchange proximity interaction between the ferromagnetic insulator and graphene. In view of the spin beam splitting effect and the spin-dependent GH shifts, the gate-controllable ferromagnetic graphene might be utilized to design spin beam splitter
Spin-dependent Goos–Hänchen shift and spin beam splitter in gate-controllable ferromagnetic graphene
Energy Technology Data Exchange (ETDEWEB)
Wang, Y. [School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Liu, Y., E-mail: stslyl@mail.sysu.edu.cn [School of Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Wang, B., E-mail: wangbiao@mail.sysu.edu.cn [School of Physics and Engineering, Sun Yat-sen University, Guangzhou 510275 (China)
2014-03-15
The transmission and Goos–Hänchen (GH) shift for charge carriers in gate-controllable ferromagnetic graphene induced by ferromagnetic insulator are investigated theoretically. Numerical results demonstrate that spin-up and spin-down electrons exhibit remarkably different transmission and GH shifts. The spin-dependent GH shifts directly demonstrate the spin beam splitting effect, which can be controlled by the voltage of gate. We attribute the spin beam splitting effect to the combination of tunneling through potential barrier and Zeeman interaction from the magnetic field and the exchange proximity interaction between the ferromagnetic insulator and graphene. In view of the spin beam splitting effect and the spin-dependent GH shifts, the gate-controllable ferromagnetic graphene might be utilized to design spin beam splitter.
International Nuclear Information System (INIS)
Baishya, R.; Jamil, U.; Sarma, J. K.
2009-01-01
In this paper the spin-dependent singlet and nonsinglet structure functions have been obtained by solving Dokshitzer, Gribov, Lipatov, Altarelli, Parisi evolution equations in leading order and next to leading order in the small x limit. Here we have used Taylor series expansion and then the method of characteristics to solve the evolution equations. We have also calculated t and x evolutions of deuteron structure functions, and the results are compared with the SLAC E-143 Collaboration data.
Adamczyk, L.; Adams, J. R.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Ajitanand, N. N.; Alekseev, I.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bairathi, V.; Barish, K.; Behera, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Brown, D.; Bryslawskyj, J.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chankova-Bunzarova, N.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Dedovich, T. G.; Deng, J.; Deppner, I. M.; Derevschikov, A. A.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Efimov, L. G.; Elsey, N.; Engelage, J.; Eppley, G.; Esha, R.; Esumi, S.; Evdokimov, O.; Ewigleben, J.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Federicova, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Fujita, J.; Fulek, L.; Gagliardi, C. A.; Geurts, F.; Gibson, A.; Girard, M.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Harlenderova, A.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Herrmann, N.; Hirsch, A.; Horvat, S.; Huang, X.; Huang, H. Z.; Huang, T.; Huang, B.; Humanic, T. J.; Huo, P.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kapukchyan, D.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z.; Kikoła, D. P.; Kim, C.; Kisel, I.; Kisiel, A.; Kochenda, L.; Kocmanek, M.; Kollegger, T.; Kosarzewski, L. K.; Kraishan, A. F.; Krauth, L.; Kravtsov, P.; Krueger, K.; Kulathunga, N.; Kumar, L.; Kvapil, J.; Kwasizur, J. H.; Lacey, R.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, W.; Li, C.; Li, X.; Li, Y.; Lidrych, J.; Lin, T.; Lisa, M. A.; Liu, Y.; Liu, H.; Liu, F.; Liu, P.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Luo, S.; Ma, L.; Ma, Y. G.; Ma, G. L.; Ma, R.; Magdy, N.; Majka, R.; Mallick, D.; Margetis, S.; Markert, C.; Matis, H. S.; Mayes, D.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mizuno, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nemes, D. B.; Nie, M.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Nonaka, T.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Salur, S.; Sandweiss, J.; Saur, M.; Schambach, J.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Schweid, B. R.; Seger, J.; Sergeeva, M.; Seto, R.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Shen, W. Q.; Shi, S. S.; Shi, Z.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stewart, D. J.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, X.; Sun, X. M.; Sun, Y.; Surrow, B.; Svirida, D. N.; Tang, Z.; Tang, A. H.; Taranenko, A.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Tu, B.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vasiliev, A. N.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, Y.; Wang, Y.; Wang, F.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, G.; Xie, W.; Xu, N.; Xu, Y. F.; Xu, Q. H.; Xu, Z.; Yang, Y.; Yang, C.; Yang, S.; Yang, Q.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J.; Zhang, S.; Zhang, J.; Zhang, S.; Zhang, Z.; Zhang, Y.; Zhang, L.; Zhang, X. P.; Zhao, J.; Zhong, C.; Zhou, C.; Zhou, L.; Zhu, X.; Zhu, Z.; Zyzak, M.
2018-05-01
The transversity distribution, which describes transversely polarized quarks in transversely polarized nucleons, is a fundamental component of the spin structure of the nucleon, and is only loosely constrained by global fits to existing semi-inclusive deep inelastic scattering (SIDIS) data. In transversely polarized p↑ + p collisions it can be accessed using transverse polarization dependent fragmentation functions which give rise to azimuthal correlations between the polarization of the struck parton and the final state scalar mesons. This letter reports on spin dependent di-hadron correlations measured by the STAR experiment. The new dataset corresponds to 25 pb-1 integrated luminosity of p↑ + p collisions at √{ s } = 500 GeV, an increase of more than a factor of ten compared to our previous measurement at √{ s } = 200 GeV. Non-zero asymmetries sensitive to transversity are observed at a Q2 of several hundred GeV and are found to be consistent with the former measurement and a model calculation. We expect that these data will enable an extraction of transversity with comparable precision to current SIDIS datasets but at much higher momentum transfers where subleading effects are suppressed.
Energy Technology Data Exchange (ETDEWEB)
Hassel, Christoph
2009-08-11
room temperature and 0.4% at 4.2 K. These values can be explained within a theoretical model considering spin-dependent scattering. Current induced domain wall motion, which is the basic principle of a recently proposed non-volatile memory, is studied in epitaxial Fe wires and, additionally, in multilayer-wires with perpendicular magnetic anisotropy. By means of magnetic force microscopy and Kerr microscopy, the movement of domain walls due to injected current pulses is observed. This effect can be explained by the influence of the Oersted eld or the increased temperature due to the current pulses. No contributions of the Spin-Torque effect are observed within the measurements. (orig.)
Spin-dependent tunneling conductance in 2D structures in zero magnetic field
International Nuclear Information System (INIS)
Rozhansky, I.V.; Averkiev, N.S.
2009-01-01
The influence of the spin-orbit interaction on the tunneling between two-dimensional electron layers is considered. A general expression for the tunneling current is obtained with the Rashba and Dresselhaus effects and also elastic scattering of charge carriers on impurities taken into account. It is shown that the particular form of the tunneling conductance as a function of the voltage between layers is extremely sensitive to the relationship between the Rashba and Dresselhaus parameters. This makes it possible to determine the parameters of the spin-orbit interaction and the quantum scattering time directly from measurements of the tunneling conductance in the absence of magnetic field
International Nuclear Information System (INIS)
Gonzalez Trotter, D. E.; Tornow, W.; Howell, C. R.; Salinas, F.; Walter, R. L.; Witalea, H.
1999-01-01
The 1 S 0 neutron-neutron (nn) scattering length's currently accepted value (a nn =-18.6±0.3 fm) is derived exclusively from two π - -d capture-reaction experiments, in disagreement with the average -16.7±0.5 fm extracted from kinematically-complete nd breakup experiments. This discrepancy may be due to deficiencies in the analyses of n-d breakup data and/or three-nucleon force (3NF) effects. A kinematically-complete n+d→n 1 +n 2 +p breakup experiment at an incident neutron energy of 13.0 MeV was performed recently at TUNL. The value of a nn was extracted from the direct comparison of experimental and rigorously-calculated theoretical nd breakup differential cross sections at four production angles of the nn pair. Using modern nucleon-nucleon potential models in the three-nucleon cross-section calculations we obtained a nn =-18.7±0.6 fm, in agreement with the π - -d result. We found no significant effect due to 3NFs on our a nn value
Maruyama, R.; Yamazaki, D.; Akutsu, K.; Hanashima, T.; Miyata, N.; Aoki, H.; Takeda, M.; Soyama, K.
2018-04-01
The multilayer structure of Fe/Si and Fe/Ge systems fabricated by ion beam sputtering (IBS) was investigated using X-ray and polarized neutron reflectivity measurements and scanning transmission electron microscopy with energy-dispersive X-ray analysis. The obtained result revealed that the incorporation of sputtering gas particles (Ar) in the Ge layer gives rise to a marked reduction in the neutron scattering length density (SLD) and contributes to the SLD contrast between the Fe and Ge layers almost vanishing for spin-down neutrons. Bundesmann et al. (2015) have shown that the implantation of primary Ar ions backscattered at the target is responsible for the incorporation of Ar particles and that the fraction increases with increasing ion incidence angle and increasing polar emission angle. This leads to a possibility of fine-tuning of the SLD for the IBS, which is required to realize a high polarization efficiency of a neutron polarizing supermirror. Fe/Ge polarizing supermirror with m = 5 fabricated under the same condition showed a spin-up reflectivity of 0.70 at the critical momentum transfer. The polarization was higher than 0.985 for the qz range where the correction for the polarization inefficiencies of the beamline works properly. The result of the polarized neutron reflectivity measurement suggests that the "magnetically-dead" layers formed at both sides of the Fe layer, together with the SLD contrast, play a critical role in determining the polarization performance of a polarizing supermirror.
Energy Technology Data Exchange (ETDEWEB)
Aprile, E; Cantale, G; Degli-Agosti, S; Hausammann, R; Heer, E; Hess, R; Lechanoine-LeLuc, C; Leo, W; Morenzoni, S; Onel, Y [Geneva Univ. (Switzerland). Dept. de Physique Nucleaire et Corpusculaire
1983-01-01
The aim of the elastic pp experimental program at SIN was to measure enough spin dependent parameters in order to do a direct experimental reconstruction of the elastic scattering amplitudes at a few energies between 400 and 600 MeV and at several angles between 38/sup 0/ cm and 90/sup 0/ cm. This reconstruction was not possible until recently due to lack of experimental data. Information instead has come mainly from phase shift analysis (PSA). The only way to extract the elastic scattering amplitudes without any hypotheses except those of basic symmetries, is to measure a sufficient set of spin dependent parameters at a given angle and energy. With this in view, the authors have measured at 448, 494, 515, 536 and 579 MeV, the polarization, the spin correlation parameters Asub(00nn), Asub(00ss), Asub(00kk), Asub(00ks), the 2-spin parameters Dsub(n0n0), Ksub(n00n), Dsub(s'0s0), Dsub(s'0k0) and the 3-spin parameters Msub(s'0sn), Msub(s'0kn) between 34/sup 0/ cm and 118/sup 0/ cm. A few of these parameters have also been measured at 560 and 470 MeV and at a few energies below 448 MeV. The indices refer to the polarization orientation of the scattered, recoil, beam and target particle respectively.
Donne, A. J. H.
1994-01-01
Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wave vector is much larger than the plasma Debye length, the total scattered power is
First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process
Czech Academy of Sciences Publication Activity Database
Aghasyan, M.; Akhunzyanov, R.; Alexeev, G. D.; Alexeev, M.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlák, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S. U.; Cicuttin, A.; Crespo, M.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S. V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, D.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jarý, V.; Joosten, R.; Joerg, P.; Kabuss, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Král, Z.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Květoň, A.; Lednev, A. A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W. D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rogacheva, N. S.; Roskot, M.; Ryabchikov, D.; Rybnikov, A.; Rychter, A.; Salač, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolík, J.; Srnka, Aleš; Steffen, D.; Stolarski, M.; Subrt, O.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takewaka, S.; Tasevsky, M.; Tessaro, S.; Terca, G.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vauth, A.; Veloso, J.; Virius, M.; Vít, M.; Vondra, J.; Wallner, S.; Weisrock, T.; Wilfert, M.; Ter Wolbeek, J.; Zaremba, K.; Závada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.
2017-01-01
Roč. 119, č. 11 (2017), s. 1-7, č. článku 112002. ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : deep-inelastic scattering * sivers asymmetries * angular-distributions Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Nuclear physics Impact factor: 8.462, year: 2016
Chandrasekar, L. Bruno; Gnanasekar, K.; Karunakaran, M.
2018-06-01
The effect of δ-potential was studied in GaAs/Ga0.6Al0·4As double barrier heterostructure with Dresselhaus spin-orbit interaction. The role of barrier height and position of the δ- potential in the well region was analysed on spin-dependent electron tunneling using transfer matrix method. The spin-separation between spin-resonances on energy scale depends on both height and position of the δ- potential, whereas the tunneling life time of electrons highly influenced by the position of the δ- potential and not on the height. These results might be helpful for the fabrication of spin-filters.
International Nuclear Information System (INIS)
Gonzalez Trotter, D.E.; Meneses, F. Salinas; Tornow, W.; Howell, C.R.; Chen, Q.; Crowell, A.S.; Roper, C.D.; Walter, R.L.; Schmidt, D.; Witala, H.; Gloeckle, W.; Tang, H.; Zhou, Z.; Slaus, I.
2006-01-01
We report on results of a kinematically complete neutron-deuteron breakup experiment performed at Triangle Universities Nuclear Laboratory using an E n =13 MeV incident neutron beam. The 1 S 0 neutron-neutron scattering length a nn has been determined for four production angles of the neutron-neutron final-state interaction configuration. The absolute cross-section data were analyzed with rigorous three-nucleon calculations. Our average value of a nn =-18.7±0.7 fm is in excellent agreement with a nn =-18.6±0.4 fm obtained from capture experiments of negative pions on deuterons. We also performed a shape analysis of the final-state interaction cross-section enhancements by allowing the normalization of the data to float. From these relative data, we obtained an average value of a nn =-18.8±0.5 fm, in agreement with the result obtained from the absolute cross-section measurements. Our result deviates from the world average of a nn =-16.7±0.5 fm determined from previous kinematically complete neutron-deuteron breakup experiments, including the most recent one carried out at Bonn. However, this low value for a nn is at variance with theoretical expectation and other experimental information about the sign of charge-symmetry breaking of the nucleon-nucleon interaction. In agreement with theoretical predictions, no evidence was found of significant three-nucleon force effects on the neutron-neutron final-state interaction cross sections
On the twist-2 and twist-3 contributions to the spin-dependent electroweak structure functions
International Nuclear Information System (INIS)
Bluemlein, J.; Kochelev, N.
1997-01-01
The twist-2 and twist-3 contributions of the polarized deep-inelastic structure functions are calculated both for neutral and charged current interactions using the operator product expansion in lowest order in QCD. The relations between the different structure functions are determined. New integral relations are derived between the twist-2 contributions of the structure functions g 3 (x,Q 2 ) and g 5 (x,Q 2 ) and between combinations of the twist-3 contributions to the structure functions g 2 (x,Q 2 ) and g 3 (x,Q 2 ). The sum rules for polarized deep-inelastic scattering are discussed in detail. (orig.)
The deuteron spin-dependent structure function and its first moment
Czech Academy of Sciences Publication Activity Database
Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Alexeev, M.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Becker, M.; Bedfer, Y.; Bernet, C.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Das, S.; Dasgupta, S. S.; De Masi, R.; Dedek, N.; Demchenko, D.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Dinkelbach, A. M.; Donskov, S.V.; Dorofeev, V. A.; Doshita, N.; Duic, V.; Dunnweber, W.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger jr., M.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.A.; Grasso, A.; Grube, B.; Guskov, A.; Haas, F.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Horn, I.; Ilgner, C.; Ioukaev, A.I.; Ivanchin, I.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N. I.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kouznetsov, O.; Kowalik, K.; Kramer, D.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kubart, J.; Kuhn, R.; Kukhtin, V.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lednev, A.A.; Lehmann, A.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Masek, L.; Massmann, F.; Matsuda, T.; Matthia, D.; Maximov, A.N.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Nagel, T.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nikolaev, K.; Nozdrin, A.A.; Obraztsov, V. F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Popov, A.A.; Pretz, J.; Procureur, S.; Quintans, C.; Ramos, S.; Reicherz, G.; Rondio, E.; Rozhdestvensky, A.M.; Ryabchikov, D.; Samoylenko, V.D.; Sandacz, A.; Santos, H.; Sapozhnikov, M.G.; Savin, I.A.; Schiavon, P.; Schill, C.; Schmitt, L.; Schroeder, W.; Seeharsch, D.; Seimetz, M.; Setter, D.; Shevchenko, O.Yu.; Siebert, H.-W.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sozzi, F.; Srnka, Aleš; Stinzing, F.; Stolarski, M.; Sugonyaev, V.P.; Sulc, M.; Sulej, R.; Tchalishev, V.V.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Trippel, S.; Venugopal, G.; Virius, M.; Vlassov, N.V.; Webb, R.; Weise, E.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Zhao, J.; Ziegler, R.; Zvyagin, A.
2007-01-01
Roč. 647, č. 1 (2007), s. 8-17 ISSN 0370-2693 R&D Projects: GA MŠk ME 492 Institutional research plan: CEZ:AV0Z20650511 Keywords : Deep inelastic scattering * Spin * Structure function * QCD analysis * A1 * g1 Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.189, year: 2007 http://www.sciencedirect.com/science/article/B6TVN-4MYVG5P-1/2/387d70e7f30fb736514de259c62118d9
Directory of Open Access Journals (Sweden)
Kunito Fukuda
2017-08-01
Full Text Available Spin-dependent space-charge-limited carrier conduction in a Schottky barrier diode using polycrystalline p-type π-conjugated molecular pentacene is explored using multiple-frequency electrically detected magnetic resonance (EDMR spectroscopy with a variable-angle configuration. The measured EDMR spectra are decomposed into two components derived, respectively, from mobile and trapped positive polarons. The linewidth of the EDMR signal for the trapped polarons increases with increasing resonance magnetic field for an in-plane configuration where the normal vector of the device substrate is perpendicular to the resonance magnetic field, while it is independent of the field for an out-of-plane configuration. This difference is consistent with the pentacene arrangement on the device substrate, where pentacene molecules exhibit a uniaxial orientation on the out-of-substrate plane. By contrast, the mobile polarons do not show anisotropic behavior with respect to the resonance magnetic field, indicating that the anisotropic effect is averaged out owing to carrier motion. These results suggest that the orientational arrangements of polycrystalline pentacene molecules in a nano thin film play a crucial role in spin-dependent electrical conduction.
Fukuda, Kunito; Asakawa, Naoki
2017-08-01
Spin-dependent space charge limited carrier conduction in a Schottky barrier diode using polycrystalline p-type π-conjugated molecular pentacene is explored using multiple-frequency electrically detected magnetic resonance (EDMR) spectroscopy with a variable-angle configuration. The measured EDMR spectra are decomposed into two components derived respectively from mobile and trapped positive polarons. The linewidth of the EDMR signal for the trapped polarons increases with increasing resonance magnetic field for an in-plane configuration where the normal vector of the device substrate is perpendicular to the resonance magnetic field, while it is independent of the field for an out-of-plane configuration. This difference is consistent with the pentacene arrangement on the device substrate, where pentacene molecules exhibit a uniaxial orientation on the out-of-substrate plane. By contrast, the mobile polarons do not show anisotropic behavior with respect to the resonance magnetic field, indicating that the anisotropic effect is averaged out owing to carrier motion. These results suggest that the orientational arrangements of polycrystalline pentacene molecules in a nano thin film play a crucial role in spin-dependent electrical conduction.
Nucleon-nucleon scattering at LAMPF and KEK
International Nuclear Information System (INIS)
Glass, G.
1988-01-01
A review of current measurements of spin-dependent observables in p-p and n-p scattering is given for experiments done at two laboratories, Clinton P. Anderson Meson Physics Facility at Los Alamos (LAMPF) and the National Laboratory for High Energy Physics in Japan (KEK). 18 refs., 12 figs
Quantum dynamics of a particle with a spin-dependent velocity
International Nuclear Information System (INIS)
Aslangul, Claude
2005-01-01
We study the dynamics of a particle in continuous time and space, the displacement of which is governed by an internal degree of freedom (spin). In one definite limit, the so-called quantum random walk is recovered but, although quite simple, the model possesses a rich variety of dynamics and goes far beyond this problem. Generally speaking, our framework can describe the motion of an electron in a magnetic sea near the Fermi level when linearization of the dispersion law is possible, coupled to a transverse magnetic field. Quite unexpected behaviours are obtained. In particular, we find that when the initial wave packet is fully localized in space, the J z angular momentum component is frozen; this is an interesting example of an observable which, although it is not a constant of motion, has a constant expectation value. For a non-completely localized wave packet, the effect still occurs although less pronounced, and the spin keeps for ever memory of its initial state. Generally speaking, as time goes on, the spatial density profile looks rather complex, as a consequence of the competition between drift and precession, and displays various shapes according to the ratio between the Larmor period and the characteristic time of flight. The density profile gradually changes from a multimodal quickly moving distribution when the scattering rate is small, to a unimodal standing but flattening distribution in the opposite case
International Nuclear Information System (INIS)
Beck, D.H.; Filippone, B.W.; Jourdan, J.
1988-01-01
It is possible to measure the deep-inelastic spin-dependent structure functions g 1 /sup p/(x) and g 1 /sup n/(x) for the proton and neutron using internal polarized hydrogen, deuterium, and 3 He targets of polarization 50% and thickness 10 14 to 10 15 cm -2 and the 60 mA longitudinally polarized 30 GeV electron beam in the HERA electron storage ring. The measurement of the deep-inelastic spin-structure of both isospin states of the nucleon at the same kinematics and using the same apparatus allows the Bjorken sum rule to be experimentally checked. In addition, it uniquely constrains the spin distribution of the u and d quarks as a function of x in any model of the nucleon. Possible target and detector configurations are described and an estimate of the accuracy of such a measurement is presented
Deutsch, Maxime; Claiser, Nicolas; Pillet, Sébastien; Chumakov, Yurii; Becker, Pierre; Gillet, Jean Michel; Gillon, Béatrice; Lecomte, Claude; Souhassou, Mohamed
2012-11-01
New crystallographic tools were developed to access a more precise description of the spin-dependent electron density of magnetic crystals. The method combines experimental information coming from high-resolution X-ray diffraction (XRD) and polarized neutron diffraction (PND) in a unified model. A new algorithm that allows for a simultaneous refinement of the charge- and spin-density parameters against XRD and PND data is described. The resulting software MOLLYNX is based on the well known Hansen-Coppens multipolar model, and makes it possible to differentiate the electron spins. This algorithm is validated and demonstrated with a molecular crystal formed by a bimetallic chain, MnCu(pba)(H(2)O)(3)·2H(2)O, for which XRD and PND data are available. The joint refinement provides a more detailed description of the spin density than the refinement from PND data alone.
International Nuclear Information System (INIS)
Baktybaev, K.; Koilyk, N.; Ramankulov, K.
2006-01-01
Full text: Collective Schrodinger equations are applied to describe low-energy spectra of even-even nuclei [1]. Spectra for even-odd nuclei are calculated by coupling the single particle degrees of freedom to the collective degree of freedom of the core nucleus, which is of even-even type. The collective spin has a value of 3/2. This leads to the assumption that the linearized equation may be applied to describe nuclei with spin 3/2 in the ground state. Good description of the low energy spectra and electromagnetic transition probabilities can be obtained only with introduction of spin-dependent potentials, which apart from coordinates and momenta also depend on the matrices of the Clifford algebra arising in the linearization,. The interacting boson-fermion models (IBFM) [2] represent another approach to describe spectra of even-odd nuclei. For even-odd nuclei with spin 3/2 in the ground state one uses so-called j=3/2 - IBFM, which is also denoted as the U B (6)xU F (4) IBFM. In this paper we establish the relation between the matrices of the Clifford algebra, which arise in the linearization procedure, and the fermion operators of the j=3/2 IBFM. This allows us to establish a connection between the j=3/2 IBFM and spin dependent generalized collective model (SGCM). The results of the SGCM for Ir and Au nuclei are presented and compared with the results of the j=3/2 IBFM with a dynamical spin symmetry [3] present. In this respect we could apply the linearized collective Schrodinger equation and IBFM with arbitrary spin to all other even-odd nuclei. (author)
International Nuclear Information System (INIS)
Tullney, Kathlynne
2014-01-01
The standard model (SM) of particle physics describes all known particles and their interactions. However, the SM leaves many issues unresolved. For example, it only includes three of the four fundamental forces and does not clarify the question why in the strong interaction CP symmetry is violated due to its non-trivial vacuum structure is predicted (Θ-term), but experimentally unverifiable. The latter one is known as the strong CP-problem of quantum chromodynamics (QCD) and is solved by the Peccei-Quinn-Weinberg-Wilczek theory. This theory predicts a new and almost massless boson which is known as the axion. The axion feebly interacts with matter and therefore it is a good candidate for cold dark matter, too. Axions are produced by the Primakoff-effect, i.e. by conversion of photons which are scattered in the electromagnetic field, e.g. of atoms. The inverse Primakoff-effect, which converts axions to photons again, can be used for direct detection of galactic, solar, or laboratory axions. Cosmological and astrophysical observations constrain the mass of the axion from a few μeV to some meV (''axion mass window''). If the axion exists, then it mediates a CP violating, spin-dependent, short-range interaction between a fermion and the spin of another fermion. By verification of this interaction, the axion can be detected indirectly. In the framework of the present thesis an experiment to search for this spindependent short-range interaction was performed in the magnetically shielded room BMSR-2 of the Physikalisch-Technische Bundesanstalt Berlin. An ultra-sensitive low-field co-magnetometer was employed which is based on the detection of free precession of 3 He and 129 Xe nuclear spins using SQUIDs as low-noise magnetic flux detectors. The two nuclear spin polarized gases are filled into a glass cell which is immersed in a low magnetic field of about B 0 = 0.35 μT with absolute field gradients in the order of pT/cm. The spin precession frequencies of 3 He and 129
Lectures on magnetism and neutron scattering
International Nuclear Information System (INIS)
Gunn, J.M.F.
1983-12-01
The paper contains six lectures given to the Neutron Division of the Rutherford Appleton laboratory in 1983. The aim was to explain fundamental physics of neutron scattering and basic magnetism to the non-specialist scientist. The text includes: origin of neutron's magnetic moment and spin-dependent interactions with electrons and nuclei, why are solids magnetic, magnetic anistropy and domain structure, phenomenological spin waves, magnetic phase transitions and electronic excitations in magnets. (U.K.)
Kanada-En'yo, Yoshiko; Isaka, Masahiro; Motoba, Toshio
2018-01-01
Energy spectra of $0s$-orbit $\\Lambda$ states in $p$-shell $\\Lambda$ hypernuclei ($^{A}_\\Lambda Z$) and those in $^{19}_{\\Lambda}\\textrm{F}$ are studied with the microscopic cluster model and antisymmetrized molecular dynamics using the $G$-matrix effective $\\Lambda N$ ($\\Lambda NG$) interactions. Spin-dependent terms of the ESC08a version of the $\\Lambda NG$ interactions are tested and phenomenologically tuned to reproduce observed energy spectra in $p$-shell $^{A}_\\Lambda Z$. Spin-dependent...
Energy Technology Data Exchange (ETDEWEB)
Yamamoto, Akihisa, E-mail: ayamamoto@icems.kyoto-u.ac.jp, E-mail: tanaka@uni-heidelberg.de; Tanaka, Motomu, E-mail: ayamamoto@icems.kyoto-u.ac.jp, E-mail: tanaka@uni-heidelberg.de [Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg (Germany); Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto 606-8501 (Japan); Abuillan, Wasim; Körner, Alexander [Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg (Germany); Burk, Alexandra S. [Physical Chemistry of Biosystems, Institute of Physical Chemistry, University of Heidelberg, 69120 Heidelberg (Germany); Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, 76021 Karlsruhe (Germany); Ries, Annika [Institute of Organic and Biomolecular Chemistry, University of Göttingen, 37077 Göttingen (Germany); Werz, Daniel B. [Institute of Organic Chemistry, Technische Universität Braunschweig, 38106 Braunschweig (Germany); Demé, Bruno [Institut Laue-Langevin, 38042 Grenoble Cedex 9, Grenoble (France)
2015-04-21
The mechanical properties of multilayer stacks of Gb3 glycolipid that play key roles in metabolic disorders (Fabry disease) were determined quantitatively by using specular and off-specular neutron scattering. Because of the geometry of membrane stacks deposited on planar substrates, the scattered intensity profile was analyzed in a 2D reciprocal space map as a function of in-plane and out-of-plane scattering vector components. The two principal mechanical parameters of the membranes, namely, bending rigidity and compression modulus, can be quantified by full calculation of scattering functions with the aid of an effective cut-off radius that takes the finite sample size into consideration. The bulkier “bent” Gb3 trisaccharide group makes the membrane mechanics distinctly different from cylindrical disaccharide (lactose) head groups and shorter “bent” disaccharide (gentiobiose) head groups. The mechanical characterization of membranes enriched with complex glycolipids has high importance in understanding the mechanisms of diseases such as sphingolipidoses caused by the accumulation of non-degenerated glycosphingolipids in lysosomes or inhibition of protein synthesis triggered by the specific binding of Shiga toxin to Gb3.
Topics in deep inelastic scattering
International Nuclear Information System (INIS)
Wandzura, S.M.
1977-01-01
Several topics in deep inelastic lepton--nucleon scattering are discussed, with emphasis on the structure functions appearing in polarized experiments. The major results are: infinite set of new sum rules reducing the number of independent spin dependent structure functions (for electroproduction) from two to one; the application of the techniques of Nachtmann to extract the coefficients appearing in the Wilson operator product expansion; and radiative corrections to the Wilson coefficients of free field theory. Also discussed are the use of dimensional regularization to simplify the calculation of these radiative corrections
International Nuclear Information System (INIS)
Raisali, G.; Hamidi, S.; Hallajfard, E.; Shahvar, A.; Hajiloo, N.
2007-01-01
The shadow cone technique is one of the methods which is used for determining the contribution of scattered particles on the response of neutron detectors. This technique is used for neutron field calibration in Agriculture, Medicine and Industry Research School. In this investigation, we have designed and constructed an optimized shadow cone. According to the calculated neutron dose equivalent attenuation factors, a cone with 20 cm of iron and 30 cm of polyethylene has been found as optimum. For this cone, the neutron dose equivalent attenuation factor for 241 Am/Be neutron source, is 0.00035 for which the contribution of scattered neutrons in Agriculture, Medicine and Industry Research School neutron calibration laboratory according to the calculation and measurement results, can be evaluated with less than 0.5% of error
International Nuclear Information System (INIS)
Zhou, Benliang; Zhou, Benhu; Liu, Guang; Guo, Dan; Zhou, Guanghui
2016-01-01
We study theoretically the spin-dependent transport and the current-induced spin transfer torque (STT) for a zigzag silicene nanoribbon (ZSiNR) with Anderson-type disorders between two ferromagnetic electrodes. By using the nonequilibrium Green's function method, it is predicted that the transport property and STT through the junction depend sensitively on the disorder, especially around the Dirac point. As a result, the conductance decreases and increases for two electrode in parallel and antiparallel configurations, respectively. Due to the disorder, the magnetoresistance (MR) decreases accordingly even within the energy regime for the perfect plateau without disorders. In addition, the conductance versus the relative angle of the magnetization shows a cosine-like behavior. The STT per unit of the bias voltage versus the angle of the magnetization exhibits a sine-like behavior, and versus the Fermi energy is antisymmetrical to the Dirac point and exhibits sharp peaks. Furthermore, the peaks of the STT are suppressed much as the disorder strength increases, especially around the Dirac point. The results obtained here may provide a valuable suggestion to experimentally design spin valve devices based on ZSiNR.
International Nuclear Information System (INIS)
Zhang, Hu; Dai, Jian-Qing; Song, Yu-Min
2016-01-01
We investigate the magnetoelectric coupling and spin-polarized tunneling in Ni/KNbO_3/Ni multiferroic tunnel junctions with asymmetric interfaces based on density functional theory. The junctions have two stable polarization states. We predict a peculiar magnetoelectric effect in such junctions originating from the magnetic reconstruction of Ni near the KO-terminated interface. This reconstruction is induced by the reversal of the ferroelectric polarization of KNbO_3. Furthermore, the change in the magnetic ordering filters the spin-dependent current. This effect leads to a change in conductance by about two orders of magnitude. As a result we obtain a giant tunneling electroresistance effect. In addition, there exist sizable tunneling magnetoresistance effects for two polarization states. - Highlights: • We study the ME coupling and electron tunneling in Ni/KNbO_3/Ni junctions. • There is magnetic reconstruction of Ni atoms near the KO-terminated interface. • A peculiar magnetoelectric coupling effect is obtained. • Predicted giant tunneling electroresistance effects.
Energy Technology Data Exchange (ETDEWEB)
Zhou, Benliang [Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Synergetic Innovation Center for Quantum Effects and Applications of Hunan, Hunan Normal University, Changsha 410081 (China); Zhou, Benhu [Department of Physics, Shaoyang University, Shaoyang 422001 (China); Liu, Guang; Guo, Dan [Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Synergetic Innovation Center for Quantum Effects and Applications of Hunan, Hunan Normal University, Changsha 410081 (China); Zhou, Guanghui, E-mail: ghzhou@hunnu.edu.cn [Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education), Synergetic Innovation Center for Quantum Effects and Applications of Hunan, Hunan Normal University, Changsha 410081 (China)
2016-11-01
We study theoretically the spin-dependent transport and the current-induced spin transfer torque (STT) for a zigzag silicene nanoribbon (ZSiNR) with Anderson-type disorders between two ferromagnetic electrodes. By using the nonequilibrium Green's function method, it is predicted that the transport property and STT through the junction depend sensitively on the disorder, especially around the Dirac point. As a result, the conductance decreases and increases for two electrode in parallel and antiparallel configurations, respectively. Due to the disorder, the magnetoresistance (MR) decreases accordingly even within the energy regime for the perfect plateau without disorders. In addition, the conductance versus the relative angle of the magnetization shows a cosine-like behavior. The STT per unit of the bias voltage versus the angle of the magnetization exhibits a sine-like behavior, and versus the Fermi energy is antisymmetrical to the Dirac point and exhibits sharp peaks. Furthermore, the peaks of the STT are suppressed much as the disorder strength increases, especially around the Dirac point. The results obtained here may provide a valuable suggestion to experimentally design spin valve devices based on ZSiNR.
Taube, Michał; Pieńkowska, Joanna R.; Jarmołowski, Artur; Kozak, Maciej
2014-01-01
SGT1 is an evolutionarily conserved eukaryotic protein involved in many important cellular processes. In plants, SGT1 is involved in resistance to disease. In a low ionic strength environment, the SGT1 protein tends to form dimers. The protein consists of three structurally independent domains (the tetratricopeptide repeats domain (TPR), the CHORD- and SGT1-containing domain (CS), and the SGT1-specific domain (SGS)), and two less conserved variable regions (VR1 and VR2). In the present study, we provide the low-resolution structure of the barley (Hordeum vulgare) SGT1 protein in solution and its dimer/monomer equilibrium using small-angle scattering of synchrotron radiation, ab-initio modeling and circular dichroism spectroscopy. The multivariate curve resolution least-square method (MCR-ALS) was applied to separate the scattering data of the monomeric and dimeric species from a complex mixture. The models of the barley SGT1 dimer and monomer were formulated using rigid body modeling with ab-initio structure prediction. Both oligomeric forms of barley SGT1 have elongated shapes with unfolded inter-domain regions. Circular dichroism spectroscopy confirmed that the barley SGT1 protein had a modular architecture, with an α-helical TPR domain, a β-sheet sandwich CS domain, and a disordered SGS domain separated by VR1 and VR2 regions. Using molecular docking and ab-initio protein structure prediction, a model of dimerization of the TPR domains was proposed. PMID:24714665
Li, Dongde; Wu, Di; Zhang, Xiaojiao; Zeng, Bowen; Li, Mingjun; Duan, Haiming; Yang, Bingchu; Long, Mengqiu
2018-05-01
The spin-dependent electronic transport properties of M(dcdmp)2 (M = Cu, Au, Co, Ni; dcdmp = 2,3-dicyano-5,6-dimercaptopyrazyne) molecular devices based on zigzag graphene nanoribbon (ZGNR) electrodes were investigated by density functional theory combined nonequilibrium Green's function method (DFT-NEGF). Our results show that the spin-dependent transport properties of the M(dcdmp)2 molecular devices can be controlled by the spin configurations of the ZGNR electrodes, and the central 3d-transition metal atom can introduce a larger magnetism than that of the nonferrous metal one. Moreover, the perfect spin filtering effect, negative differential resistance, rectifying effect and magnetic resistance phenomena can be observed in our proposed M(dcdmp)2 molecular devices.
A Large-Acceptance Detector System for Electron Scattering from Polarized Internal targets.
Passchier, E.; Bouwhuis, M.; Choi, S.; Zhou, Z.L.; Alarcon, R.; Anghinolfi, M.; Botto, T.; van den Brand, J.F.J.; Bulten, H.J.; Dimitroyannis, D.; Doets, M.; Ent, R.; Ferro Luzzi, M.M.E.; Higinbotham, D.W.; de Jager, C.W.; Lang, J.; de Lange, D.J.; Nikolenko, D.; Nooren, G.J.; Papadakis, N.; Passchier, I.; Popov, S.G.; Rachek, I.; Ripani, M.; Steijger, J.J.M.; Taiuti, M.; Vodinas, N.; de Vries, H.
1997-01-01
The design and the performance of a non-magnetic detector setup for internal target physics at the NIKHEF electron-scattering facility is described. The detector setup, used in the first internal-target experiment at the AmPS ring, measures the spin dependence in the elastic and break-up reaction
On the theory of elastic scattering of spin polarized electrons from ferromagnets
International Nuclear Information System (INIS)
Helman, J.S.
1984-01-01
The first Born approximation supposedly inadequate for dealing with elastic scattering of spin polarized electrons on ferromagnets is reconsidered. It is found that when used in conjunction with a spin dependent pseudopotential, it can describe the gross features of the ansisotropy. (Author) [pt
On the theory of elastic scattering of spin polarized electrons from ferromagnets
International Nuclear Information System (INIS)
Helman, J.S.; Baltenspenger, W.
1984-01-01
The first Born approximation supposedly inadequate for dealing with the elastic scattering of spin polarized electrons on ferromagnets is reconsidered. It is found that when used in conjunction with a spin dependent pseudo-potential, it can describe the gross features of the anisotropy. (author) [pt
Czech Academy of Sciences Publication Activity Database
Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlák, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S.U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Dhara, L.; Donskov, S. V.; Doshita, N.; Dreisbach, Ch.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giarra, J.; Giordano, A.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F. H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jarý, V.; Joosten, R.; Jörg, P.; Kabuss, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W. D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Roskot, M.; Rossiyskaya, N. S.; Ryabchikov, D.; Rybnikov, A.; Rychter, A.; Salač, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolík, J.; Srnka, Aleš; Steffen, D.; Stolarski, M.; Subrt, O.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Thiel, A.; Tosello, F.; Tskhay, V.; Uhl, S.; Vauth, A.; Veloso, J.; Virius, M.; Vondra, J.; Wallner, S.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Ter Wolbeek, J.; Zaremba, K.; Závada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.
2017-01-01
Roč. 769, JUNE (2017), s. 34-41 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * deep inelastic scattering * spin * structure function * parton helicity distributions Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Nuclear physics Impact factor: 4.807, year: 2016
The spin-dependent structure function of the proton g(1)(p) and a test of the Bjorken sum rule
Czech Academy of Sciences Publication Activity Database
Alekseev, M.; Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Amoroso, A.; Austregisilio, A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.; Chaberny, D.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Cotic, D.; Crespo, M.; Dalla Torre, S.; Das, S.; Dasgupta, S. S.; Denisov, O.; Dhara, L.; Diaz, V.; Donskov, S.; Doshita, N.; Duic, V.; Dünnweber, W.; Efremov, A.V.; El Alaoui, A.; Eversheim, P.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Friedrich, J.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gazda, R.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmüller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Haas, F.; von Harrach, D.; Hasegawa, T.; Heinsius, F.; Hermann, R.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Höppner, Ch.; d'Hose, N.; Ilgner, C.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jasinski, P.; Jegou, G.; Joosten, R.; Kabuss, E.; Käfer, W.; Kang, D.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.; Kolosov, V.; Kondo, K.; Königsmann, K.; Konopka, R.; Konorov, I.; Konstantinov, V.; Korzenev, A.; Kotzinian, A.; Kouznetsov, O.; Kowalik, K.; Krämer, M.; Kral, A.; Kroumchtein, Z.; Kuhn, R.; Kunne, F.; Kurek, K.; Lauser, L.; Le Goff, J.; Lednev, A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Liska, T.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.; Mann, A.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Massmann, F.; Matsuda, T.; Meyer, W.; Michigami, T.; Mikhailov, Y.; Moinester, M.; Mutter, A.; Nagaytsev, A.; Nagel, T.; Nassalski, J.; Negrini, S.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.; Nunes, A.S.; Olshevsky, A.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pawlukiewicz-Kaminska, B.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.; Pontecorvo, G.; Pretz, J.; Quintans, C.; Rajotte, J.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ryabchikov, D.; Samoylenko, V.; Sandacz, A.; Santos, H.; Sapozhnikov, M.; Sarkar, S.; Savin, I.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlütter, T.; Schmitt, L.; Schopferer, S.; Schröder, W.; Shevchenko, O.; Siebert, H.; Silva, L.; Sinha, L.; Sissakian, A.; Slunecka, M.; Smirnov, G.; Sosio, S.; Sozzi, F.; Srnka, Aleš; Stolarski, M.; Sulc, M.; Sulej, R.; Takekawa, S.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.; Uhl, S.; Uman, I.; Virius, M.; Vlassov, N.; Vossen, A.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhao, J.; Zhuravlev, N.; Zvyagin, A.
2010-01-01
Roč. 690, č. 5 (2010), s. 466-472 ISSN 0370-2693 R&D Projects: GA MŠk ME 492 Institutional research plan: CEZ:AV0Z20650511 Keywords : deep inelastic scattering * structure function * QCD analysis * Bjorken sum rule Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 5.255, year: 2010
Energy Technology Data Exchange (ETDEWEB)
Kim, J; Park, Y; Sharp, G; Winey, B [Massachusetts General Hospital and Harvard Medical School, Boston, MA (United States)
2016-06-15
Purpose: To establish a method to evaluate the dosimetric impact of anatomic changes in head and neck patients during proton therapy by using scatter-corrected cone-beam CT (CBCT) images. Methods: The water equivalent path length (WEPL) was calculated to the distal edge of PTV contours by using tomographic images available for six head and neck patients received photon therapy. The proton range variation was measured by calculating the difference between the distal WEPLs calculated with the planning CT and weekly treatment CBCT images. By performing an automatic rigid registration, six degrees-of-freedom (DOF) correction was made to the CBCT images to account for the patient setup uncertainty. For accurate WEPL calculations, an existing CBCT scatter correction algorithm, whose performance was already proven for phantom images, was calibrated for head and neck patient images. Specifically, two different image similarity measures, mutual information (MI) and mean square error (MSE), were tested for the deformable image registration (DIR) in the CBCT scatter correction algorithm. Results: The impact of weight loss was reflected in the distal WEPL differences with the aid of the automatic rigid registration reducing the influence of patient setup uncertainty on the WEPL calculation results. The WEPL difference averaged over distal area was 2.9 ± 2.9 (mm) across all fractions of six patients and its maximum, mostly found at the last available fraction, was 6.2 ± 3.4 (mm). The MSE-based DIR successfully registered each treatment CBCT image to the planning CT image. On the other hand, the MI-based DIR deformed the skin voxels in the planning CT image to the immobilization mask in the treatment CBCT image, most of which was cropped out of the planning CT image. Conclusion: The dosimetric impact of anatomic changes was evaluated by calculating the distal WEPL difference with the existing scatter-correction algorithm appropriately calibrated. Jihun Kim, Yang-Kyun Park
Zemlyanichkina, Elena
2014-01-01
New results of the double spin asymmetry A p 1 and the spin-dependent structure function of the proton g p 1 as a function of x Bj and Q 2 will be presented. New COMPASS data on longitudinal polarized NH 3 target were collected during the year 2011 with a beam of positive muons with energy E = 200 GeV. It allows us to cover low x region down to 0 : 0025 in the range Q 2 > 1 GeV = c 2 for the first time
Ageev, E.S.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.P.; Bytchkov, V.N.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.A.; Costa, S.; Crespo, M.L.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S.S.; De Masi, R.; Dedek, N.; Denisov, O.Yu.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.M.; Dolgopolov, A.V.; Donskov, S.V.; Dorofeev, V.A.; Doshita, N.; Duic, V.; Dunnweber, W.; Ehlers, J.; Eversheim, P.D.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franz, J.; Friedrich, J.M.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.M.; Grajek, O.A.; Grasso, A.; Grube, B.; Grunemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.H.; Hermann, R.; He, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.B.; Ilgner, C.; Ioukaev, A.I.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N.I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Khomutov, N.V.; Kisselev, Yu.; Klein, F.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Komissarov, E.V.; Kondo, K.; Konigsmann, Kay; Konoplyannikov, A.K.; Konorov, I.; Konstantinov, V.F.; Korentchenko, A.S.; Korzenev, A.; Kotzinian, A.M.; Koutchinski, N.A.; Kowalik, K.; Kravchuk, N.P.; Krivokhizhin, G.V.; Kroumchtein, Z.V.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.E.; Lamanna, M.; Le Goff, J.M.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Manuilov, I.V.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.N.; Medved, K.S.; Meyer, W.; Mielech, A.; Mikhailov, Yu.V.; Moinester, M.A.; Nahle, O.; Nassalski, J.; Neliba, S.; Neyret, D.P.; Nikolaenko, V.I.; Nozdrin, A.A.; Obraztsov, V.F.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.D.; Peshekhonov, D.V.; Peshekhonov, V.D.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.A.; Popov, A.A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.C.; Reicherz, G.; Reymann, J.; Rith, K.; Rozhdestvensky, A.M.; Rondio, E.; Sadovski, A.B.; Saller, E.; Samoylenko, V.D.; Sandacz, A.; Sans, M.; Sapozhnikov, M.G.; Savin, Igor A.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Shevchenko, O.Yu.; Shishkin, A.A.; Siebert, H.-W.; Sinha, L.; Sissakian, A.N.; Skachkova, A.; Slunecka, M.; Smirnov, G.I.; Sozzi, F.; Sugonyaev, V.P.; Srnka, A.; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.V.; Tessarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.G.; Toeda, T.; Tretyak, V.I.; Trusov, Sergey V.; Varanda, M.; Virius, M.; Vlassov, N.V.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.M.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.
2007-01-01
We present a precise measurement of the deuteron longitudinal spin asymmetry $A_1^d$ and of the deuteron spin-dependent structure function $g_1^d$ at $Q^2 < $ 1~(GeV/$c$)$^2$ and $4\\cdot$10$^{-5} < x < $~2.5$\\cdot$10$^{-2}$ based on the data collected by the COMPASS experiment at CERN during the years 2002 and 2003. The statistical precision is tenfold better than that of the previous measurement in this region. The measured $A_1^d$ and $g_1^d$ are found to be consistent with zero in the whole range of $x$.
Sharov, V. I.; Anischenko, N. G.; Antonenko, V. G.; Averichev, S. A.; Azhgirey, L. S.; Bartenev, V. D.; Bazhanov, N. A.; Belyaev, A. A.; Blinov, N. A.; Borisov, N. S.; Borzakov, S. B.; Borzunov, Yu. T.; Bushuev, Yu. P.; Chernenko, L. P.; Chernykh, E. V.; Chumakov, V. F.; Dolgh, S. A.; Fedorov, A. N.; Fimushkin, V. V.; Finger, M.; Finger, M.; Golovanov, L. B.; Gurevich, G. M.; Guriev, D. K.; Janata, A.; Kirillov, A. D.; Kolomiets, V. G.; Komogorov, E. V.; Kovalenko, A. D.; Kovalev, A. I.; Krasnov, V. A.; Krstonoshich, P.; Kuzmin, E. S.; Kuzmin, N. A.; Ladygin, V. P.; Lazarev, A. B.; Lehar, F.; de Lesquen, A.; Liburg, M. Yu.; Livanov, A. N.; Lukhanin, A. A.; Maniakov, P. K.; Matafonov, V. N.; Matyushevsky, E. A.; Moroz, V. D.; Morozov, A. A.; Neganov, A. B.; Nikolaevsky, G. P.; Nomofilov, A. A.; Panteleev, Tz.; Pillpenko, Yu. K.; Pisarev, I. L.; Plis, Yu. A.; Polunin, Yu. P.; Prokofiev, A. N.; Prytkov, V. Yu.; Rukoyatkin, P. A.; Schedrov, V. A.; Schevelev, O. N.; Shilov, S. N.; Shindin, R. A.; Slunecka, M.; Slunečková, V.; Starikov, A. Yu.; Stoletov, G. D.; Strunov, L. N.; Svetov, A. L.; Usov, Yu. A.; Vasiliev, T.; Volkov, V. I.; Vorobiev, E. I.; Yudin, I. P.; Zaitsev, I. V.; Zhdanov, A. A.; Zhmyrov, V. N.
2005-01-01
New accurate data on the neutron-proton spin-dependent total cross section difference Δ σ L( np) at the neutron beam kinetic energies 1.4, 1.7, 1.9 and 2.0 GeV are presented. A number of physical and methodical results on investigation of an elastic np→pn charge exchange process over a few GeV region are also presented. Measurements were carried out at the Synchrophasotron and Nuclotron of the Veksler and Baldin Laboratory of High Energies of the Joint Institute for Nuclear Research.
International Nuclear Information System (INIS)
Chang, S.; Coriano, C.; Elwood, J.K.
1997-01-01
The authors investigate the role of the transverse spin dependence in Drell Yan lepton pair production to NLO in QCD at parton level. In the analysis the authors deal with the large p Τ distributions. They give very compact expressions for the virtual O(α s 2 ) corrections to the cross section and show that the singularities factorize. The study is performed in the MS scheme in Dimensional Regularization, and with the t'Hooft-Veltman prescription for γ 5 . A discussion of the structure of the real emissions is included, and detailed methods for the study of these contributions are formulated
Institute of Scientific and Technical Information of China (English)
YANGYong－Hong; WANGYong－Gang; 等
2002-01-01
Two kinds of spin-dependent scattering effects (magnetic-impurity and spin-orbit scatterings) are investigated theoretically in a quasi-tow-dimensional (quasi-2D) disordered electron system.By making use of the diagrammatic techniques in perturbation theory,we have calculated the dc conductivity and magnetoresistance due to weak-localization effects,the analytical expressions of them are obtained as functions of the interlayer hopping energy and the characteristic times:elastic,inelastic,magnetic and spin-orbit scattering times.The relevant dimensional crossover behavior from 3D to 2D with decreasing the interlayer coupling is discussed,and the condition for the crossover is shown to be dependent on the aforementioned scattering times.At low temperature there exists a spin-dependent-scattering-induced dimensional crossover in this system.
Calculating scattering matrices by wave function matching
International Nuclear Information System (INIS)
Zwierzycki, M.; Khomyakov, P.A.; Starikov, A.A.; Talanana, M.; Xu, P.X.; Karpan, V.M.; Marushchenko, I.; Brocks, G.; Kelly, P.J.; Xia, K.; Turek, I.; Bauer, G.E.W.
2008-01-01
The conductance of nanoscale structures can be conveniently related to their scattering properties expressed in terms of transmission and reflection coefficients. Wave function matching (WFM) is a transparent technique for calculating transmission and reflection matrices for any Hamiltonian that can be represented in tight-binding form. A first-principles Kohn-Sham Hamiltonian represented on a localized orbital basis or on a real space grid has such a form. WFM is based upon direct matching of the scattering-region wave function to the Bloch modes of ideal leads used to probe the scattering region. The purpose of this paper is to give a pedagogical introduction to WFM and present some illustrative examples of its use in practice. We briefly discuss WFM for calculating the conductance of atomic wires, using a real space grid implementation. A tight-binding muffin-tin orbital implementation very suitable for studying spin-dependent transport in layered magnetic materials is illustrated by looking at spin-dependent transmission through ideal and disordered interfaces. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
International Nuclear Information System (INIS)
Kuehnelt, H.
1975-01-01
We discuss a few properties of scattering amplitudes proved within the framework of the field theory and their significance in the derivation of quantitative statements. The state of the boundaries for the scattering lengths is to be especially discussed as well as the question as to how far it is possible to exclude various solutions from phase displacement analyses. (orig./LH) [de
Donne, A. J. H.
1996-01-01
Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wave vector is much larger than the plasma Debye length, the total scattered power is
Energy Technology Data Exchange (ETDEWEB)
Cavalcanti Malta, Pedro
2017-06-27
It is well known that the Standard Model is not complete and many of the theories that seek to extend it predict new phenomena that may be accessible in low-energy settings. This thesis deals with some of these, namely, novel spin-dependent interparticle potentials, axion-like particles and Lorentz-symmetry violation. In Part I we discuss the spin-dependent potentials that arise due to the exchange of a topologically massive mediator, and also pursue a comparative study between spin-1/2 and spin-1 sources. In Part II we treat massive axion-like particles that may be copiously produced in core-collapse supernovae, thus leading to a non-standard flux of gamma rays. Using SN 1987A and the fact that after its observation no extra gamma-ray signal was detected, we are able to set robust limits on the parameter space of axion-like particles with masses in the 10 keV - 100 MeV range. Finally, in Part III we investigate the effects of Lorentz-breaking backgrounds in QED. We discuss two scenarios: a modification in the Maxwell sector via the Carroll-Field-Jackiw term and a new non-minimal coupling between electrons and photons. We are able to set upper limits on the coefficients of the backgrounds by using laboratory-based measurements.
International Nuclear Information System (INIS)
Lebedenko, V. N.; Bewick, A.; Currie, A.; Davidge, D.; Dawson, J.; Horn, M.; Howard, A. S.; Jones, W. G.; Joshi, M.; Liubarsky, I.; Lyons, K.; Quenby, J. J.; Sumner, T. J.; Thorne, C.; Walker, R. J.; Araujo, H. M.; Edwards, B.; Barnes, E. J.; Ghag, C.; Murphy, A. StJ.
2009-01-01
We present new experimental constraints on the WIMP-nucleon spin-dependent elastic cross sections using data from the first science run of ZEPLIN-III, a two-phase xenon experiment searching for galactic dark matter weakly interacting massive particles based at the Boulby mine. Analysis of ∼450 kg·days fiducial exposure allow us to place a 90%-confidence upper limit on the pure WIMP-neutron cross section of σ n =1.9x10 -2 pb at 55 GeV/c 2 WIMP mass. Recent calculations of the nuclear spin structure based on the Bonn charge-dependent nucleon-nucleon potential were used for the odd-neutron isotopes 129 Xe and 131 Xe. These indicate that the sensitivity of xenon targets to the spin-dependent WIMP-proton interaction could be much lower than implied by previous calculations, whereas the WIMP-neutron sensitivity is impaired only by a factor of ∼2.
International Nuclear Information System (INIS)
Eslami, Leila; Esmaeilzadeh, Mahdi
2014-01-01
Spin-dependent electron transport in an open double quantum ring, when each ring is made up of four quantum dots and threaded by a magnetic flux, is studied. Two independent and tunable gate voltages are applied to induce Rashba spin-orbit effect in the quantum rings. Using non-equilibrium Green's function formalism, we study the effects of electron-electron interaction on spin-dependent electron transport and show that although the electron-electron interaction induces an energy gap, it has no considerable effect when the bias voltage is sufficiently high. We also show that the double quantum ring can operate as a spin-filter for both spin up and spin down electrons. The spin-polarization of transmitted electrons can be tuned from −1 (pure spin-down current) to +1 (pure spin-up current) by changing the magnetic flux and/or the gates voltage. Also, the double quantum ring can act as AND and NOR gates when the system parameters such as Rashba coefficient are properly adjusted
International Nuclear Information System (INIS)
Dai, Jian-Qing; Zhang, Hu; Song, Yu-Min
2015-01-01
We report on first-principles calculations of a Ni monolayer inserted at one interface in the epitaxial Fe/PbTiO 3 /Fe multiferroic heterostructure, focusing on the magnetoelectric coupling and the spin-dependent transport properties. The results of magnetoelectric coupling calculations reveal an attractive approach to realize cumulative magnetoelectric effects in the ferromagnetic/ferroelectric/ferromagnetic superlattices. The underlying physics is attributed to the combinations of several different magnetoelectric coupling mechanisms such as interface bonding, spin-dependent screening, and different types of magnetic interactions. We also demonstrate that inserting a Ni monolayer at one interface in the Fe/PbTiO 3 /Fe multiferroic tunnel junction is an efficient method to produce considerable tunneling electroresistance effect by modifying the tunnel potential barrier and the interfacial electronic structure. Furthermore, coexistence of tunneling magnetoresistance and tunneling electroresistance leads to the emergence of four distinct resistance states, which can be served as a multistate-storage device. The complicated influencing factors including bulk properties of the ferromagnetic electrodes, decay rates of the evanescent states in the tunnel barrier, and the specific interfacial electronic structure provide us promising opportunities to design novel multiferroic tunnel junctions with excellent performances
Energy Technology Data Exchange (ETDEWEB)
Dai, Jian-Qing, E-mail: djqkust@sina.com; Zhang, Hu; Song, Yu-Min [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)
2015-08-07
We report on first-principles calculations of a Ni monolayer inserted at one interface in the epitaxial Fe/PbTiO{sub 3}/Fe multiferroic heterostructure, focusing on the magnetoelectric coupling and the spin-dependent transport properties. The results of magnetoelectric coupling calculations reveal an attractive approach to realize cumulative magnetoelectric effects in the ferromagnetic/ferroelectric/ferromagnetic superlattices. The underlying physics is attributed to the combinations of several different magnetoelectric coupling mechanisms such as interface bonding, spin-dependent screening, and different types of magnetic interactions. We also demonstrate that inserting a Ni monolayer at one interface in the Fe/PbTiO{sub 3}/Fe multiferroic tunnel junction is an efficient method to produce considerable tunneling electroresistance effect by modifying the tunnel potential barrier and the interfacial electronic structure. Furthermore, coexistence of tunneling magnetoresistance and tunneling electroresistance leads to the emergence of four distinct resistance states, which can be served as a multistate-storage device. The complicated influencing factors including bulk properties of the ferromagnetic electrodes, decay rates of the evanescent states in the tunnel barrier, and the specific interfacial electronic structure provide us promising opportunities to design novel multiferroic tunnel junctions with excellent performances.
International Nuclear Information System (INIS)
Li, Xin-Mei; Long, Meng-Qiu; Cui, Li-Ling; Xiao, Jin; Zhang, Xiao-Jiao; Zhang, Dan; Xu, Hui
2014-01-01
Based on nonequilibrium Green's function in combination with density functional theory calculations, the spin-dependent electronic transport properties of one-dimensional zigzag molybdenum disulfide (MoS 2 ) nanoribbons with V-shaped defect and H-saturation on the edges have been studied. Our results show that the spin-polarized transport properties can be found in all the considered zigzag MoS 2 nanoribbons systems. The edge defects, especially the V-shaped defect on the Mo edge, and H-saturation on the edges can suppress the electronic transport of the systems. Also, the spin-filtering and negative differential resistance behaviors can be observed obviously. The mechanisms are proposed for these phenomena. - Highlights: • The spin-dependent electronic transport of zigzag MoS 2 nanoribbons. • The effects of V-shaped edge defect and H-saturation. • The effects of spin-filter and negative differential resistance can be observed
Fundamental length and relativistic length
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1988-01-01
It si noted that the introduction of fundamental length contradicts the conventional representations concerning the contraction of the longitudinal size of fast-moving objects. The use of the concept of relativistic length and the following ''elongation formula'' permits one to solve this problem
Earth Data Analysis Center, University of New Mexico — Flame length was modeled using FlamMap, an interagency fire behavior mapping and analysis program that computes potential fire behavior characteristics. The tool...
Spin-dependent electron-phonon coupling in the valence band of single-layer WS_{2}
DEFF Research Database (Denmark)
Hinsche, Nicki Frank; Ngankeu, Arlette S.; Guilloy, Kevin
2017-01-01
The absence of inversion symmetry leads to a strong spin-orbit splitting of the upper valence band of semiconducting single-layer transition-metal dichalchogenides such as MoS2 or WS2. This permits a direct comparison of the electron-phonon coupling strength in states that only differ by their spin....... Here, the electron-phonon coupling in the valence band maximum of single-layer WS2 is studied by first-principles calculations and angle-resolved photoemission. The coupling strength is found to be drastically different for the two spin-split branches, with calculated values of λK=0.0021 and 0.......40 for the upper and lower spin-split valence band of the freestanding layer, respectively. This difference is somewhat reduced when including scattering processes involving the Au(111) substrate present in the experiment but it remains significant, in good agreement with the experimental results....
Scattering of polarized low-energy electrons by ferromagnetic metals
International Nuclear Information System (INIS)
Helman, J.S.
1981-01-01
A source of spin polarized electrons with remarkable characteristics based on negative electron affinity (NEA) GaAs has recently been developed. It constitutes a unique tool to investigate spin dependent interactions in electron scattering processes. The characteristics and working principles of the source are briefly described. Some theoretical aspects of the scattering of polarized low-energy electrons by ferromagnetic metals are discussed. Finally, the results of the first polarized low-energy electron diffraction experiment using the NEA GaAs source are reviewed; they give information about the surface magnetization of ferromagnetic Ni (110). (Author) [pt
International Nuclear Information System (INIS)
Pradhan, T.
1975-01-01
The concept of fundamental length was first put forward by Heisenberg from purely dimensional reasons. From a study of the observed masses of the elementary particles known at that time, it is sumrised that this length should be of the order of magnitude 1 approximately 10 -13 cm. It was Heisenberg's belief that introduction of such a fundamental length would eliminate the divergence difficulties from relativistic quantum field theory by cutting off the high energy regions of the 'proper fields'. Since the divergence difficulties arise primarily due to infinite number of degrees of freedom, one simple remedy would be the introduction of a principle that limits these degrees of freedom by removing the effectiveness of the waves with a frequency exceeding a certain limit without destroying the relativistic invariance of the theory. The principle can be stated as follows: It is in principle impossible to invent an experiment of any kind that will permit a distintion between the positions of two particles at rest, the distance between which is below a certain limit. A more elegant way of introducing fundamental length into quantum theory is through commutation relations between two position operators. In quantum field theory such as quantum electrodynamics, it can be introduced through the commutation relation between two interpolating photon fields (vector potentials). (K.B.)
Energy Technology Data Exchange (ETDEWEB)
Kanaki, Toshiki, E-mail: kanaki@cryst.t.u-tokyo.ac.jp; Asahara, Hirokatsu; Ohya, Shinobu, E-mail: ohya@cryst.t.u-tokyo.ac.jp; Tanaka, Masaaki, E-mail: masaaki@ee.t.u-tokyo.ac.jp [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
2015-12-14
We fabricate a vertical spin metal-oxide-semiconductor field-effect transistor (spin-MOSFET) structure, which is composed of an epitaxial single-crystal heterostructure with a ferromagnetic-semiconductor GaMnAs source/drain, and investigate its spin-dependent transport properties. We modulate the drain-source current I{sub DS} by ∼±0.5% with a gate-source voltage of ±10.8 V and also modulate I{sub DS} by up to 60% with changing the magnetization configuration of the GaMnAs source/drain at 3.5 K. The magnetoresistance ratio is more than two orders of magnitude higher than that obtained in the previous studies on spin MOSFETs. Our result shows that a vertical structure is one of the hopeful candidates for spin MOSFET when the device size is reduced to a sub-micron or nanometer scale.
Thermal stability study of the insulator layer in NiFe/CoFe/Al2O3/Co spin-dependent tunnel junction
International Nuclear Information System (INIS)
Liao, C.C.; Ho, C.H.; Huang, R.-T.; Chen, F.-R.; Kai, J.J.; Chen, L.-C.; Lin, M.-T.; Yao, Y.D.
2002-01-01
Spin-dependent tunnel junction, NiFe/CoFe/Al 2 O 3 /Co//Si, was fabricated to investigate the thermal stability induced diffusion behaviors. The interfacial diffusion causes the degradation of the ratio of the TMR, the enhancement of the switching field of the two magnetic electrodes, the thickness decrease of the insulator layer, and the increase of the interfacial roughness. The outward diffusion of oxygen from the insulator layer is faster than that of aluminum for samples annealed below 400 deg. C. The degradation of the ratio of TMR is attributed to the disturbance of the spin polarization in the magnetic layers, and the increase of the pinholes and spin-flip effect in the insulator layer. The relative roughness between the two interfaces of the insulator induces the surface magnetic dipoles, and hence, increases the switching field of the ferromagnetic electrodes
International Nuclear Information System (INIS)
Kanaki, Toshiki; Asahara, Hirokatsu; Ohya, Shinobu; Tanaka, Masaaki
2015-01-01
We fabricate a vertical spin metal-oxide-semiconductor field-effect transistor (spin-MOSFET) structure, which is composed of an epitaxial single-crystal heterostructure with a ferromagnetic-semiconductor GaMnAs source/drain, and investigate its spin-dependent transport properties. We modulate the drain-source current I DS by ∼±0.5% with a gate-source voltage of ±10.8 V and also modulate I DS by up to 60% with changing the magnetization configuration of the GaMnAs source/drain at 3.5 K. The magnetoresistance ratio is more than two orders of magnitude higher than that obtained in the previous studies on spin MOSFETs. Our result shows that a vertical structure is one of the hopeful candidates for spin MOSFET when the device size is reduced to a sub-micron or nanometer scale
Badelek, Barbara
2018-01-01
This paper summarizes the COMPASS Collaboration legacy on measurements of the proton and deuteron spin-dependent structure functions, $g_1^p$ and $g_1^d$ at $Q^2 1$ (GeV/c)$^2$. In both regions and at the lowest measured $x, g^d_1 (x)$ is consistent with zero while $g^p_1 (x)$ is positive. This is the first time that the spin effects are observed at such low values of $x$. The NLO QCD fit of $g_1$ world data gives well constrained quark helicity distributions; gluons are poorly determined. Quark helicity contribution to nucleon spin is $0.26 < \\Delta \\Sigma < 0.36$. From the COMPASS data alone the Bjorken sum rule is verified to $9\\%$ accuracy and the extracted flavour-singlet axial charge is $a_0 (Q^2 = 3 (\\text{GeV/}c)^2) = 0.32 \\pm 0.02_{stat.} \\pm 0.04_{syst.} \\pm 0.05_{evol.}$.
Directory of Open Access Journals (Sweden)
S. Mohammad Moosavi Nejad
2017-08-01
Full Text Available In recent years, searches for the light and heavy charged Higgs bosons have been done by the ATLAS and the CMS collaborations at the Large Hadron Collider (LHC in proton–proton collision. Nevertheless, a definitive search is a program that still has to be carried out at the LHC. The experimental observation of charged Higgs bosons would indicate physics beyond the Standard Model. In the present work, we study the scaled-energy distribution of bottom-flavored mesons (B inclusively produced in polarized top quark decays into a light charged Higgs boson and a massless bottom quark at next-to-leading order in the two-Higgs-doublet model; t(↑→bH+→BH++X. This spin-dependent energy distribution is studied in a specific helicity coordinate system where the polarization vector of the top quark is measured with respect to the direction of the Higgs momentum. The study of these energy distributions could be considered as a new channel to search for the charged Higgs bosons at the LHC. For our numerical analysis and phenomenological predictions, we restrict ourselves to the unexcluded regions of the MSSM mH+−tanβ parameter space determined by the recent results of the CMS [13] and ATLAS [14] collaborations.
Badelek, Barbara
2017-01-01
This paper summarizes the COMPASS Collaboration legacy on measurements of the proton and deuteron spin-dependent structure functions, $g_1^p$ and $g_1^d$ at $Q^2 1$ (GeV/c)$^2$. In both regions and at the lowest measured $x, g^d_1 (x)$ is consistent with zero while $g^p_1 (x)$ is positive. This is the first time that the spin effects are observed at such low values of $x$. The NLO QCD fit of $g_1$ world data gives well constrained quark helicity distributions; gluons are poorly determined. Quark helicity contribution to nucleon spin is $0.26 < \\Delta \\Sigma < 0.36$. From the COMPASS data alone the Bjorken sum rule is verified to $9\\%$ accuracy and the extracted flavour-singlet axial charge is $a_0 (Q^2 = 3 (\\text{GeV/}c)^2) = 0.32 \\pm 0.02_{stat.} \\pm 0.04_{syst.} \\pm 0.05_{evol.}$.
Elastic scattering of polarized protons on helium three at 800 MeV
International Nuclear Information System (INIS)
Azizi, A.
1985-07-01
A set of spin dependent parameters and cross sections has been measured for polarized p- 3 He elastic scattering over the range of q .7 to 4.2 fm -1 . The experiment was done at the Los Alamos Meson Physics Facility (LAMPF) using the High Resolution Spectrometer (HRS) with a polarized proton beam at .8 GeV. The focal plane polarimeter of the HRS was used to determine the spin direction of the scattered proton. Since 3 He is one of the simplest nuclei, polarized p- 3 He scattering provides a very sensitive test of multiple scattering theories. The theoretical analysis was done by using two different wave functions for 3 He as input to the multiple scattering theory. The theoretical calculations and experimental data together will give us useful information about nucleon-nucleon amplitudes and also help us to obtain a better understanding of the scattering process. 68 refs., 55 figs., 9 tabs
Mansikkamäki, Akseli; Popov, Alexey A.; Deng, Qingming; Iwahara, Naoya; Chibotaru, Liviu F.
2017-09-01
The magnetic properties and electronic structure of the ground and excited states of two recently characterized endohedral metallo-fullerenes, [Gd2@C78]- (1) and [Gd2@C80]- (2), have been studied by theoretical methods. The systems can be considered as [Gd2]5+ dimers encapsulated in a fullerene cage with the fifteen unpaired electrons ferromagnetically coupled into an S = 15/2 high-spin configuration in the ground state. The microscopic mechanisms governing the Gd-Gd interactions leading to the ferromagnetic ground state are examined by a combination of density functional and ab initio calculations and the full energy spectrum of the ground and lowest excited states is constructed by means of ab initio model Hamiltonians. The ground state is characterized by strong electron delocalization bordering on a σ type one-electron covalent bond and minor zero-field splitting (ZFS) that is successfully described as a second order spin-orbit coupling effect. We have shown that the observed ferromagnetic interaction originates from Hund's rule coupling and not from the conventional double exchange mechanism. The calculated ZFS parameters of 1 and 2 in their optimized geometries are in qualitative agreement with experimental EPR results. The higher excited states display less electron delocalization, but at the same time they possess unquenched first-order angular momentum. This leads to strong spin-orbit coupling and highly anisotropic energy spectrum. The analysis of the excited states presented here constitutes the first detailed study of the effects of spin-dependent delocalization in the presence of first order orbital angular momentum and the obtained results can be applied to other mixed valence lanthanide systems.
Butler, Christopher John; Yang, Po-Ya; Sankar, Raman; Lien, Yen-Neng; Lu, Chun-I; Chang, Luo-Yueh; Chen, Chia-Hao; Wei, Ching-Ming; Chou, Fang-Cheng; Lin, Minn-Tsong
2016-09-28
Observations of quasiparticle interference have been used in recent years to examine exotic carrier behavior at the surfaces of emergent materials, connecting carrier dispersion and scattering dynamics to real-space features with atomic resolution. We observe quasiparticle interference in the strongly Rashba split 2DEG-like surface band found at the tellurium termination of BiTeBr and examine two mechanisms governing quasiparticle scattering: We confirm the suppression of spin-flip scattering by comparing measured quasiparticle interference with a spin-dependent elastic scattering model applied to the calculated spectral function. We also use atomically resolved STM maps to identify point defect lattice sites and spectro-microscopy imaging to discern their varying scattering strengths, which we understand in terms of the calculated orbital characteristics of the surface band. Defects on the Bi sublattice cause the strongest scattering of the predominantly Bi 6p derived surface band, with other defects causing nearly no scattering near the conduction band minimum.
Introduction to Schroedinger inverse scattering
International Nuclear Information System (INIS)
Roberts, T.M.
1991-01-01
Schroedinger inverse scattering uses scattering coefficients and bound state data to compute underlying potentials. Inverse scattering has been studied extensively for isolated potentials q(x), which tend to zero as vertical strokexvertical stroke→∞. Inverse scattering for isolated impurities in backgrounds p(x) that are periodic, are Heaviside steps, are constant for x>0 and periodic for x<0, or that tend to zero as x→∞ and tend to ∞ as x→-∞, have also been studied. This paper identifies literature for the five inverse problems just mentioned, and for four other inverse problems. Heaviside-step backgrounds are discussed at length. (orig.)
Single Crystal Diffuse Neutron Scattering
Directory of Open Access Journals (Sweden)
Richard Welberry
2018-01-01
Full Text Available Diffuse neutron scattering has become a valuable tool for investigating local structure in materials ranging from organic molecular crystals containing only light atoms to piezo-ceramics that frequently contain heavy elements. Although neutron sources will never be able to compete with X-rays in terms of the available flux the special properties of neutrons, viz. the ability to explore inelastic scattering events, the fact that scattering lengths do not vary systematically with atomic number and their ability to scatter from magnetic moments, provides strong motivation for developing neutron diffuse scattering methods. In this paper, we compare three different instruments that have been used by us to collect neutron diffuse scattering data. Two of these are on a spallation source and one on a reactor source.
Energy Technology Data Exchange (ETDEWEB)
T' Jampens, B
2002-12-15
Precise knowledge of cold-atom collision properties is essential for the studies of Bose-Einstein condensation or cold molecule formation. In such experiments, the interaction mainly occurs at rather large interatomic distance, in the so-called asymptotic region. We have developed a purely asymptotic method which allows us to fully describe the collision properties of cold alkali atoms without using the inner part of the molecular potentials, which is often known with a poor precision. The key point of the method is the setting of nodal lines, which are the lines connecting the nodes of successive radial wavefunctions near the ground state threshold. Within the framework of Born-Oppenheimer approximation, computing such nodal lines, by numerical integration of the radial Schroedinger equation in the asymptotic region only, provides a very simple way to derive scattering lengths from observed bound level positions. The method has been extended to the multichannel case and appears now as a genuine parametric method, in which a few parameters (some chosen nodal lines) replace the inner part of the potentials. These nodal lines are used as fitting parameters, which are adjusted on experimental results. Once these parameters have been determined, any collision property such as scattering lengths, clock shifts or magnetic field induced Feshbach resonances can be deduced in principle. This method has been applied to obtain the collision properties of ultracold sodium and cesium atoms. (author)
Czech Academy of Sciences Publication Activity Database
Alexakhin, V.; Alexandrov, Y.; Alexeev, G.; Amoroso, A.; Badelek, B.; Balestra, F.; Ball, J.; Baum, G.; Bedfer, Y.; Berglund, P.; Bernet, C.; Bertini, R.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Burtin, E.; Bussa, M.; Bytchkov, V.; Cerini, L.; Chapiro, A.; Cicuttin, A.; Colantoni, M.; Colavita, A.; Costa, S.; Crespo, M.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S. S.; De Masi, R.; Dedek, N.; Denisov, O.; Dhara, L.; Diaz Kavka, V.; Dinkelbach, A.; Dolgopolov, A.; Donskov, S.; Dorofeev, V.; Doshita, N.; Duic, V.; Dünnweber, W.; Ehlers, J.; Eversheim, P.; Eyrich, W.; Fabro, M.; Faessler, M.; Falaleev, V.; Fauland, P.; Ferrero, A.; Ferrero, L.; Finger, M.; Finger jr., M.; Fischer, H.; Franz, J.; Friedrich, J.; Frolov, V.; Fuchs, U.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gobbo, B.; Goertz, S.; Gorin, A.; Grajek, O.; Grasso, A.; Grube, B.; Grünemaier, A.; Hannappel, J.; von Harrach, D.; Hasegawa, T.; Hedicke, S.; Heinsius, F.; Hermann, R.; Hess, C.; Hinterberger, F.; von Hodenberg, M.; Horikawa, N.; Horikawa, S.; Ijaduola, R.; Ilgner, C.; Ioukaev, A.; Ishimoto, S.; Ivanov, O.; Iwata, T.; Jahn, R.; Janata, A.; Joosten, R.; Jouravlev, N. I.; Kabuss, E.; Kalinnikov, V.; Kang, D.; Karstens, F.; Kastaun, W.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Khomutov, N.; Kisselev, Y.; Klein, F.; Koblitz, S.; Koivuniemi, J.; Kolosov, V.; Komissarov, E.; Kondo, K.; Königsmann, K.; Konoplyannikov, A.; Konorov, I.; Konstantinov, V.; Korentchenko, A.; Korzenev, A.; Kotzinian, A.; Koutchinski, N.; Kowalik, K.; Kravchuk, N.; Krivokhizhin, G.; Kroumchtein, Z.; Kuhn, R.; Kunne, F.; Kurek, K.; Ladygin, M.; Lamanna, M.; Le Goff, J.; Leberig, M.; Lichtenstadt, J.; Liska, T.; Ludwig, I.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.; Manuilov, I.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Matsuda, T.; Maximov, A.; Medved, K.; Meyer, W.; Mielech, A.; Mikhailov, Y.; Moinester, M.; Nähle, O.; Nassalski, J.; Neliba, S.; Neyret, D.; Nikolaenko, V.; Nozdrin, A.; Obraztsov, V.; Olshevsky, A.; Ostrick, M.; Padee, A.; Pagano, P.; Panebianco, S.; Panzieri, D.; Paul, S.; Pereira, H.; Peshekhonov, D.; Peshekhonov, V.; Piragino, G.; Platchkov, S.; Platzer, K.; Pochodzalla, J.; Polyakov, V.; Popov, A.; Pretz, J.; Quintans, C.; Ramos, S.; Rebourgeard, P.; Reicherz, G.; Reymann, J.; Rith, K.; Rozhdestvensky, A.; Rondio, E.; Sadovski, A.; Saller, E.; Samoylenko, V.; Sandacz, A.; Sans, M.; Sapozhnikov, M.; Savin, I.; Schiavon, P.; Schill, C.; Schmidt, T.; Schmitt, H.; Schmitt, L.; Shevchenko, O.; Shishkin, A.; Siebert, H.; Sinha, L.; Sissakian, A.; Skachkova, A.; Slunecka, M.; Smirnov, G.; Sozzi, F.; Sugonyaev, V.; Srnka, Aleš; Stinzing, F.; Stolarski, M.; Sulc, M.; Sulej, R.; Takabayashi, N.; Tchalishev, V.; Tassarotto, F.; Teufel, A.; Thers, D.; Tkatchev, L.; Toeda, T.; Tretyak, V.; Trousov, S.; Varanda, M.; Virius, M.; Vlassov, N.; Wagner, M.; Webb, R.; Weise, E.; Weitzel, Q.; Wiedner, U.; Wiesmann, M.; Windmolders, R.; Wirth, S.; Wislicki, W.; Zanetti, A.; Zaremba, K.; Zhao, J.; Ziegler, R.; Zvyagin, A.
2007-01-01
Roč. 647, 5-6 (2007), s. 330-340 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) ME 492 Institutional research plan: CEZ:AV0Z20650511 Keywords : inelastic muon scattering * spin * structure function Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 4.189, year: 2007
Characterization of porous materials by small-angle scattering
Indian Academy of Sciences (India)
With the availability of ultra small-angle scattering instruments, one can investigate porous materials in the sub-micron length scale. Because of the increased accessible length scale vis-a-vis the multiple scattering effect, conventional data analysis procedures based on single scattering approximation quite often fail.
International Nuclear Information System (INIS)
Hategan, Cornel; Comisel, Horia; Ionescu, Remus A.
2004-01-01
The quasiresonant scattering consists from a single channel resonance coupled by direct interaction transitions to some competing reaction channels. A description of quasiresonant Scattering, in terms of generalized reduced K-, R- and S- Matrix, is developed in this work. The quasiresonance's decay width is, due to channels coupling, smaller than the width of the ancestral single channel resonance (resonance's direct compression). (author)
DEFF Research Database (Denmark)
Kimura, Masayuki; Hjelmborg, Jacob V B; Gardner, Jeffrey P
2008-01-01
Leukocyte telomere length, representing the mean length of all telomeres in leukocytes, is ostensibly a bioindicator of human aging. The authors hypothesized that shorter telomeres might forecast imminent mortality in elderly people better than leukocyte telomere length. They performed mortality...
Electron Effective-Attenuation-Length Database
SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge) This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).
Kaspers, O. P.; Sterenborg, H. J. C. M.; Amelink, A.
2008-01-01
We have characterized the path length for the differential path-length spectroscopy (DPS) fiber optic geometry for a wide range of optical properties and for fiber diameters ranging from 200 mu m to 1000 mu m. Phantom measurements show that the path length is nearly constant for scattering
Multiple Scattering Model for Optical Coherence Tomography with Rytov Approximation
Li, Muxingzi
2017-01-01
of speckles due to multiple scatterers within the coherence length, and other random noise. Motivated by the above two challenges, a multiple scattering model based on Rytov approximation and Gaussian beam optics is proposed for the OCT setup. Some previous
International Nuclear Information System (INIS)
Sitenko, A.
1991-01-01
This book emerged out of graduate lectures given by the author at the University of Kiev and is intended as a graduate text. The fundamentals of non-relativistic quantum scattering theory are covered, including some topics, such as the phase-function formalism, separable potentials, and inverse scattering, which are not always coverded in textbooks on scattering theory. Criticisms of the text are minor, but the reviewer feels an inadequate index is provided and the citing of references in the Russian language is a hindrance in a graduate text
International Nuclear Information System (INIS)
Stirling, W.G.; Perry, S.C.
1996-01-01
We outline the theoretical and experimental background to neutron scattering studies of critical phenomena at magnetic and structural phase transitions. The displacive phase transition of SrTiO 3 is discussed, along with examples from recent work on magnetic materials from the rare-earth (Ho, Dy) and actinide (NpAs, NpSb, USb) classes. The impact of synchrotron X-ray scattering is discussed in conclusion. (author) 13 figs., 18 refs
Ultrafast x-ray scattering on nanoparticle dynamics
International Nuclear Information System (INIS)
Plech, A; Ibrahimkutty, S; Issenmann, D; Kotaidis, V; Siems, A
2013-01-01
Pulsed X-ray scattering is used for the determination of structural dynamics of laser-irradiated gold particles. By combining several scattering methods such as powder scattering, small angle scattering and diffuse wide angle scattering it is possible to reconstruct the kinetics of structure evolution on several lengths scales and derive complementary information on the particles and their local environment. A generic structural phase diagram for the reaction as function of delay time after laser excitation and laser fluence can be constructed.
International Nuclear Information System (INIS)
Botto, D.J.; Pratt, R.H.
1979-05-01
The current status of Compton scattering, both experimental observations and the theoretical predictions, is examined. Classes of experiments are distinguished and the results obtained are summarized. The validity of the incoherent scattering function approximation and the impulse approximation is discussed. These simple theoretical approaches are compared with predictions of the nonrelativistic dipole formula of Gavrila and with the relativistic results of Whittingham. It is noted that the A -2 based approximations fail to predict resonances and an infrared divergence, both of which have been observed. It appears that at present the various available theoretical approaches differ significantly in their predictions and that further and more systematic work is required
Energy Technology Data Exchange (ETDEWEB)
Botto, D.J.; Pratt, R.H.
1979-05-01
The current status of Compton scattering, both experimental observations and the theoretical predictions, is examined. Classes of experiments are distinguished and the results obtained are summarized. The validity of the incoherent scattering function approximation and the impulse approximation is discussed. These simple theoretical approaches are compared with predictions of the nonrelativistic dipole formula of Gavrila and with the relativistic results of Whittingham. It is noted that the A/sup -2/ based approximations fail to predict resonances and an infrared divergence, both of which have been observed. It appears that at present the various available theoretical approaches differ significantly in their predictions and that further and more systematic work is required.
Incoherent Thomson scattering as a diagnostic tool
Barth, C. J.
1998-01-01
Thomson scattering is a very powerful diagnostic which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can be diagnosed. When the wavelength is much smaller than the plasma Debye length, the total scattered power is
Aghasyan, M.; The COMPASS collaboration; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anfimov, N.V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Bressan, A.; Büchele, M.; Burtsev, V.E.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chumakov, A.G.; Chung, S.-U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Dreisbach, Ch.; Dünnweber, W.; Dusaev, R.R.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Faessler, M.; Ferrero, A.; Finger, M.; jr.,M.Finger; Fischer, H.; Franco, C.; du Fresne von Hohenesche, N.; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grasso, A.; Gridin, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F.H.; Heitz, R.; Herrmann, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.M.; Kral, Z.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Kuznetsov, I.I.; Kveton, A.; Lednev, A.A.; Levchenko, E.A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Lyubovitskij, V.E.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Mamon, S.A.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.V.; Meyer, M.; Meyer, W.; Mikhailov, Yu.V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Moretti, A.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Pešková, M.; Peshekhonov, D.V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rogacheva, N.S.; Ryabchikov, D.I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thiel, A.; Tomsa, J.; Tosello, F.; Tskhay, V.; Uhl, S.; Vasilishin, B.I.; Vauth, A.; Veloso, J.; Vidon, A.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.
2018-06-10
We present a precise measurement of the proton longitudinal double-spin asymmetry A1p and the proton spin-dependent structure function g1p at photon virtualities 0.006(GeV/c)2
Spin effects in medium-energy electron-3He scattering
International Nuclear Information System (INIS)
van den Brand, J.F.J.; Alarcon, R.; Bauer, T.
1998-01-01
New physics can be accessed by scattering polarized electrons from a polarized 3 He internal gas target. It is discussed how the asymmetries for the reactions 3 vector He(vector e,e'), 3 vector He(vector e,e'p), 3 vector He(vector e,e'n), 3 vector He(vector e,e'd), and 3 vector He(vector e,e'pn) may provide precise information on the S' and the D-wave parts of the 3 He ground-state wave function, the neutron form factors, and the role of spin-dependent reaction mechanism effects. The experiment uses up to 900 MeV (polarized) electrons from the AmPS storage ring in Amsterdam, Netherlands, in combination with large acceptance electron and hadron detectors. (orig.)
Chaotic scattering and quantum dynamics
International Nuclear Information System (INIS)
Doron, Eyal.
1992-11-01
The main concern of this thesis is the application of the semiclassical approximation to quantum chaotic scattering systems. We deal with two separate, although interconnected, subjects. The first subject dealt with is the semiclassical characterization of the fluctuations of the S matrix. A particular important parameter is the magnetic field B, and we show how the correlation length and line shape of S matrix elements under a change of B may be derived. An effect which is present in many physical wave systems is absorption of energy flux. We show how absorption affects both the reflectivity and the scattering phase and time delay of a scattering system. In the second part of the thesis, we show how the formalism and results obtained from chaotic scattering can be applied to the investigation of closed chaotic systems, and in particular to chaotic billiards. The semiclassical expansion for billiards is presented. In the last part of the thesis we deal with the statistics of S matrices of chaotic scattering systems. The main message of this work is that scattering matrix, and its classical counterpart the Poincare Scattering Map can be used to yield a powerful formulation of the quantum mechanical dynamics of bounded systems. (author)
International Nuclear Information System (INIS)
Uesaka, T.; Ladygin, V.P.; Azhgirej, L.S.
2005-01-01
A new high-energy beam polarimeter is proposed for the Nuclotron using Internal Target Station. This polarimeter based on the measurement of the asymmetry for the d-p elastic scattering will allow one to measure both vector and tensor components of the deuteron beam polarization simultaneously. For that purpose the measurement of analyzing powers for the d-p elastic scattering at energies T d = 0.88-2 GeV is proposed. The precise measurements of the deuteron analyzing powers over energy range T d 300-2000 MeV can give an irreplaceable clue on the study of spin-dependence of three-nucleon forces
International Nuclear Information System (INIS)
Leader, Elliot
1991-01-01
With very few unexplained results to challenge conventional ideas, physicists have to look hard to search for gaps in understanding. An area of physics which offers a lot more than meets the eye is elastic and diffractive scattering where particles either 'bounce' off each other, emerging unscathed, or just graze past, emerging relatively unscathed. The 'Blois' workshops provide a regular focus for this unspectacular, but compelling physics, attracting highly motivated devotees
International Nuclear Information System (INIS)
1991-02-01
The annual report on hand gives an overview of the research work carried out in the Laboratory for Neutron Scattering (LNS) of the ETH Zuerich in 1990. Using the method of neutron scattering, it is possible to examine in detail the static and dynamic properties of the condensed material. In accordance with the multidisciplined character of the method, the LNS has for years maintained a system of intensive co-operation with numerous institutes in the areas of biology, chemistry, solid-state physics, crystallography and materials research. In 1990 over 100 scientists from more than 40 research groups both at home and abroad took part in the experiments. It was again a pleasure to see the number of graduate students present, who were studying for a doctorate and who could be introduced into the neutron scattering during their stay at the LNS and thus were in the position to touch on central ways of looking at a problem in their dissertation using this modern experimental method of solid-state research. In addition to the numerous and interesting ways of formulating the questions to explain the structure, nowadays the scientific programme increasingly includes particularly topical studies in connection with high temperature-supraconductors and materials research
Friedrich, Harald
2016-01-01
This corrected and updated second edition of "Scattering Theory" presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is k...
On low energy scattering theory with Coulomb potentials
International Nuclear Information System (INIS)
Gibson, A.G.
1985-09-01
The scattering length is a very useful characteristic of the scattering phenomena. But in the presence of a combined potential (e.g. in nuclear physics, when Coulomb, the polarization and the strong potentials are to be added), the analytical definition of the scattering length in not unambigous and strictly defined. This problem is discussed in detail, the various alternatives are examined and compared. A practical suggestion is given for the proper choice of the definition and for the calculation of scattering length. Numerical solutions of the Schroedinger equation are compared with the results of different definitions. Some questions of application to nuclear physics are discussed. (D.Gy.)
The dependence of scattering length on van der Waals interaction ...
Indian Academy of Sciences (India)
MSEM) recently introduced by Ray in {\\it Pramana – J. Phys.} 83, 907 (2014) are used to study the elastic collision between two hydrogen-like atoms when both are in ground states by considering the system as a four-body Coulomb system in the ...
The dependence of scattering length on van der Waals interaction ...
Indian Academy of Sciences (India)
2016-06-16
Jun 16, 2016 ... Abstract. The static exchange model (SEM) and the modified static exchange model (MSEM) recently introduced by Ray in Pramana – J. Phys. 83, 907 (2014) are used to study the elastic collision between two hydrogen-like atoms when both are in ground states by considering the system as a four-body ...
Scatter factor corrections for elongated fields
International Nuclear Information System (INIS)
Higgins, P.D.; Sohn, W.H.; Sibata, C.H.; McCarthy, W.A.
1989-01-01
Measurements have been made to determine scatter factor corrections for elongated fields of Cobalt-60 and for nominal linear accelerator energies of 6 MV (Siemens Mevatron 67) and 18 MV (AECL Therac 20). It was found that for every energy the collimator scatter factor varies by 2% or more as the field length-to-width ratio increases beyond 3:1. The phantom scatter factor is independent of which collimator pair is elongated at these energies. For 18 MV photons it was found that the collimator scatter factor is complicated by field-size-dependent backscatter into the beam monitor
Asymptotic safety, emergence and minimal length
International Nuclear Information System (INIS)
Percacci, Roberto; Vacca, Gian Paolo
2010-01-01
There seems to be a common prejudice that asymptotic safety is either incompatible with, or at best unrelated to, the other topics in the title. This is not the case. In fact, we show that (1) the existence of a fixed point with suitable properties is a promising way of deriving emergent properties of gravity, and (2) there is a sense in which asymptotic safety implies a minimal length. In doing so we also discuss possible signatures of asymptotic safety in scattering experiments.
Canela, Andrés; Klatt, Peter; Blasco, María A
2007-01-01
Most somatic cells of long-lived species undergo telomere shortening throughout life. Critically short telomeres trigger loss of cell viability in tissues, which has been related to alteration of tissue function and loss of regenerative capabilities in aging and aging-related diseases. Hence, telomere length is an important biomarker for aging and can be used in the prognosis of aging diseases. These facts highlight the importance of developing methods for telomere length determination that can be employed to evaluate telomere length during the human aging process. Telomere length quantification methods have improved greatly in accuracy and sensitivity since the development of the conventional telomeric Southern blot. Here, we describe the different methodologies recently developed for telomere length quantification, as well as their potential applications for human aging studies.
De Wolf, E.A.
2002-01-01
We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken-x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wusthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed.
International Nuclear Information System (INIS)
Wolf, E.A. de
2002-01-01
We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken - x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wuesthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed. (author)
International Nuclear Information System (INIS)
Leymarie, E.
2002-11-01
In this thesis we study the theoretical and experimental aspects of Contrast Variation by Nuclear Polarization (CVNP) applied to small-angle neutron scattering. The basics of neutron scattering theory is developed by highlighting the origin of the CVNP method: the strong spin dependence of thermal neutron scattering, especially on protons. We also present the principles of NMR with a special attention on the method of dynamic nuclear polarization by the solid effect which makes it possible to control the proton polarization and therefore the contrast for neutron scattering. We present a theoretical study of the CVNP method called static which supposes that the nuclear polarization is homogeneous in the sample and constant during the experiment. We show that it allows one to obtain partial structure functions of systems with multiple components, by carrying out several acquisitions with different polarizations on a single sample. For this purpose, we tested a simple device to stabilize the nuclear polarization. We describe finally a new application of the CVNP method called dynamic. In a solution of deuterated glycerol-water containing a small concentration of paramagnetic centres, we showed the existence of domains of polarized protons at the onset of dynamic polarization. This reinforces considerably the coherent scattering of paramagnetic centres. We describe the theoretical reasons explaining the appearance of these domains of polarization, as well as the various techniques used to observe them by neutron scattering. (author)
Telomere length and depression
DEFF Research Database (Denmark)
Wium-Andersen, Marie Kim; Ørsted, David Dynnes; Rode, Line
2017-01-01
BACKGROUND: Depression has been cross-sectionally associated with short telomeres as a measure of biological age. However, the direction and nature of the association is currently unclear. AIMS: We examined whether short telomere length is associated with depression cross-sectionally as well...... as prospectively and genetically. METHOD: Telomere length and three polymorphisms, TERT, TERC and OBFC1, were measured in 67 306 individuals aged 20-100 years from the Danish general population and associated with register-based attendance at hospital for depression and purchase of antidepressant medication....... RESULTS: Attendance at hospital for depression was associated with short telomere length cross-sectionally, but not prospectively. Further, purchase of antidepressant medication was not associated with short telomere length cross-sectionally or prospectively. Mean follow-up was 7.6 years (range 0...
Asymmetry measurements in p--p scattering with polarized beams and targets up to 12 GeV/c
International Nuclear Information System (INIS)
Auer, I.P.; Colton, E.; Halpern, H.; Hill, D.; Spinka, H.; Tamura, N.; Theodosiou, G.; Underwood, D.; Wanger, R.; Watanabe, Y.; Yokosawa, A.
1978-01-01
The processes of proton--proton scattering for various spin directions was investigated in the beam momentum range of 1 to 12 GeV/c. A striking energy dependence was observed at p/sub lab/ = 1 to 4 GeV/c, especially in Δ sigma/sub L/, the total cross section difference in the longitudinal spin states. The rapid energy dependence has been interpreted as evidence for the formation of diproton resonances. Various pp scattering parameters were measured at 6 GeV/c, including 3-spin parameters, which are sufficient to determine pp elastic scattering amplitudes in a model independent way at 0.2 2 . Measurements of spin--spin correlation parameters were extended to higher t and higher energies, revealing the importance of the spin dependent interaction. These measurements may shed light on the nature of the constituents and their interactions. 24 references
Energy Technology Data Exchange (ETDEWEB)
Li, Chun-Lei, E-mail: licl@cnu.edu.cn [Laboratory for Micro-sized Functional Materials, College of Elementary Education, Capital Normal University, Beijing 100048 (China); Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Yuan, Rui-Yang [Center for Theoretical Physics, Department of Physics, Capital Normal University, Beijing 100048 (China); Guo, Yong, E-mail: guoy66@tsinghua.edu.cn [Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)
2016-01-07
Using the effective-mass approximation and Floquet theory, we theoretically investigate the terahertz photon-assisted transport through a ZnSe/Zn{sub 1−x}Mn{sub x}Se heterostructure under an external magnetic field, an electric field, and a spatially homogeneous oscillatory field. The results show that both amplitude and frequency of the oscillatory field can accurately manipulate the magnitude of the spin-dependent transmission probability and the positions of the Fano-type resonance due to photon absorption and emission processes. Transmission resonances can be enhanced to optimal resonances or drastically suppressed for spin-down electrons tunneling through the heterostructure and for spin-up ones tunneling through the same structure, resonances can also be enhanced or suppressed, but the intensity is less than the spin-down ones. Furthermore, it is important to note that transmission suppression can be clearly seen from both the spin-down component and the spin-up component of the current density at low magnetic field; at the larger magnetic field, however, the spin-down component is suppressed, and the spin-up component is enhanced. These interesting properties may provide an alternative method to develop multi-parameter modulation electron-polarized devices.
Scattering Solar Thermal Concentrators
Energy Technology Data Exchange (ETDEWEB)
Giebink, Noel C. [Pennsylvania State Univ., State College, PA (United States)
2015-01-31
concentrator optical efficiency was found to decrease significantly with increasing aperture width beyond 0.5 m due to parasitic waveguide out-coupling loss and low-level absorption that become dominant at larger scale. A heat transfer model was subsequently implemented to predict collector fluid heat gain and outlet temperature as a function of flow rate using the optical model as a flux input. It was found that the aperture width size limitation imposed by the optical efficiency characteristics of the waveguide limits the absolute optical power delivered to the heat transfer element per unit length. As compared to state-of-the-art parabolic trough CPV system aperture widths approaching 5 m, this limitation leads to an approximate factor of order of magnitude increase in heat transfer tube length to achieve the same heat transfer fluid outlet temperature. The conclusion of this work is that scattering solar thermal concentration cannot be implemented at the scale and efficiency required to compete with the performance of current parabolic trough CSP systems. Applied within the alternate context of CPV, however, the results of this work have likely opened up a transformative new path that enables quasi-static, high efficiency CPV to be implemented on rooftops in the form factor of traditional fixed-panel photovoltaics.
Q-space analysis of scattering by particles: A review
International Nuclear Information System (INIS)
Sorensen, Christopher M.
2013-01-01
This review describes and demonstrates the Q-space analysis of light scattering by particles. This analysis involves plotting the scattered intensity versus the scattering wave vector q=(4π/λ)sin(θ/2) on a double log plot. The analysis uncovers power law descriptions of the scattering with length scale dependent crossovers between the power laws. It also systematically describes the magnitude of the scattering and the interference ripple structure that often underlies the power laws. It applies to scattering from dielectric spheres of arbitrary size and refractive index (Mie scattering), fractal aggregates and irregularly shaped particles such as dusts. The benefits of Q-space analysis are that it provides a simple and comprehensive description of scattering in terms of power laws with quantifiable exponents; it can be used to differentiate scattering by particles of different shapes, and it yields a physical understanding of scattering based on diffraction. -- Highlights: ► Angular scattering functions for spheres show power laws versus the wave vector q. ► The power laws uncover patterns involving length scales and functionalities. ► Similar power laws appear in scattering from aggregates and irregular particles. ► Power laws provide a comprehensive and quantitative description of scattering
International Nuclear Information System (INIS)
Bruyere, M.; Vallee, A.; Collette, C.
1986-09-01
Extended fuel cycle length and burnup are currently offered by Framatome and Fragema in order to satisfy the needs of the utilities in terms of fuel cycle cost and of overall systems cost optimization. We intend to point out the consequences of an increased fuel cycle length and burnup on reactor safety, in order to determine whether the bounding safety analyses presented in the Safety Analysis Report are applicable and to evaluate the effect on plant licensing. This paper presents the results of this examination. The first part indicates the consequences of increased fuel cycle length and burnup on the nuclear data used in the bounding accident analyses. In the second part of this paper, the required safety reanalyses are presented and the impact on the safety margins of different fuel management strategies is examined. In addition, systems modifications which can be required are indicated
Spin dependent spectroscopy of heavy quarkonium
International Nuclear Information System (INIS)
Gupta, Pramila; Mehrotra, I.
2011-01-01
In the present work mass spectroscopy of charmonium and bottonium systems has been studied using energy dependent quark interquark potential in the framework of non-relativistic Schroedinger wave equation. Energy dependence gives rise to nonlocality in the potential. These authors have used the interquark potential to be of the form of harmonic oscillator with a small linear energy dependent perturbation. Their main conclusion is that energy dependence can account for saturation of the energy levels at higher excitation energies, a feature that is observed experimentally
Elastic scattering of polarized protons on helium three at 800 MeV
Energy Technology Data Exchange (ETDEWEB)
Azizi, A.
1985-07-01
A set of spin dependent parameters and cross sections has been measured for polarized p-/sup 3/He elastic scattering over the range of q .7 to 4.2 fm/sup -1/. The experiment was done at the Los Alamos Meson Physics Facility (LAMPF) using the High Resolution Spectrometer (HRS) with a polarized proton beam at .8 GeV. The focal plane polarimeter of the HRS was used to determine the spin direction of the scattered proton. Since /sup 3/He is one of the simplest nuclei, polarized p-/sup 3/He scattering provides a very sensitive test of multiple scattering theories. The theoretical analysis was done by using two different wave functions for /sup 3/He as input to the multiple scattering theory. The theoretical calculations and experimental data together will give us useful information about nucleon-nucleon amplitudes and also help us to obtain a better understanding of the scattering process. 68 refs., 55 figs., 9 tabs.
Relativistic distances, sizes, lengths
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1992-01-01
Such notion as light or retarded distance, field size, formation way, visible size of a body, relativistic or radar length and wave length of light from a moving atom are considered. The relation between these notions is cleared up, their classification is given. It is stressed that the formation way is defined by the field size of a moving particle. In the case of the electromagnetic field, longitudinal sizes increase proportionally γ 2 with growing charge velocity (γ is the Lorentz-factor). 18 refs
Evaluating Multispectral Snowpack Reflectivity With Changing Snow Correlation Lengths
Kang, Do Hyuk; Barros, Ana P.; Kim, Edward J.
2016-01-01
This study investigates the sensitivity of multispectral reflectivity to changing snow correlation lengths. Matzler's ice-lamellae radiative transfer model was implemented and tested to evaluate the reflectivity of snow correlation lengths at multiple frequencies from the ultraviolet (UV) to the microwave bands. The model reveals that, in the UV to infrared (IR) frequency range, the reflectivity and correlation length are inversely related, whereas reflectivity increases with snow correlation length in the microwave frequency range. The model further shows that the reflectivity behavior can be mainly attributed to scattering rather than absorption for shallow snowpacks. The largest scattering coefficients and reflectivity occur at very small correlation lengths (approximately 10(exp -5 m) for frequencies higher than the IR band. In the microwave range, the largest scattering coefficients are found at millimeter wavelengths. For validation purposes, the ice-lamella model is coupled with a multilayer snow physics model to characterize the reflectivity response of realistic snow hydrological processes. The evolution of the coupled model simulated reflectivities in both the visible and the microwave bands is consistent with satellite-based reflectivity observations in the same frequencies. The model results are also compared with colocated in situ snow correlation length measurements (Cold Land Processes Field Experiment 2002-2003). The analysis and evaluation of model results indicate that the coupled multifrequency radiative transfer and snow hydrology modeling system can be used as a forward operator in a data-assimilation framework to predict the status of snow physical properties, including snow correlation length.
Bidirectional optical scattering facility
Federal Laboratory Consortium — Goniometric optical scatter instrument (GOSI)The bidirectional reflectance distribution function (BRDF) quantifies the angular distribution of light scattered from a...
Application of neutron scattering in polymers
International Nuclear Information System (INIS)
Han, C.C.
2003-01-01
Full text: Neutron scattering offers many opportunities in sciences and technology. This is particularly true in the field of polymer sciences and materials. It is mainly because that the scattering length scales (q -1 ) and scattering contrast (scattering cross-sections) makes neutron a perfect tool for polymer studies. Several examples will be used to illustrate the importance of the small angle neutron scattering and the neutron reflection studies in polymer physics. These include the determination of phase diagram, interaction parameter, and spinodal decomposition kinetics by SANS. In the dynamics area, examples will be given to illustrate the critical temperature shift and mixing of polymer blends under shear flow. Also, the confinement effect on the phase separated structure of polymer blend films will be used to demonstrate the importance of the neutron reflectivity measurement
Scattering theory of molecules, atoms and nuclei
Canto, L Felipe
2012-01-01
The aim of the book is to give a coherent and comprehensive account of quantum scattering theory with applications to atomic, molecular and nuclear systems. The motivation for this is to supply the necessary theoretical tools to calculate scattering observables of these many-body systems. Concepts which are seemingly different for atomic/molecular scattering from those of nuclear systems, are shown to be the same once physical units such as energy and length are diligently clarified. Many-body resonances excited in nuclear systems are the same as those in atomic systems and come under the name
Concept of formation length in radiation theory
International Nuclear Information System (INIS)
Baier, V.N.; Katkov, V.M.
2005-01-01
The features of electromagnetic processes are considered which connected with finite size of space region in which final particles (photon, electron-positron pair) are formed. The longitudinal dimension of the region is known as the formation length. If some external agent is acting on an electron while traveling this distance the emission process can be disrupted. There are different agents: multiple scattering of projectile, polarization of a medium, action of external fields, etc. The theory of radiation under influence of the multiple scattering, the Landau-Pomeranchuk-Migdal (LPM) effect, is presented. The probability of radiation is calculated with an accuracy up to 'next to leading logarithm' and with the Coulomb corrections taken into account. The integral characteristics of bremsstrahlung are given, it is shown that the effective radiation length increases due to the LPM effect at high energy. The LPM effect for pair creation is also presented. The multiple scattering influences also on radiative corrections in a medium (and an external field too) including the anomalous magnetic moment of an electron and the polarization tensor as well as coherent scattering of a photon in a Coulomb field. The polarization of a medium alters the radiation probability in soft part of spectrum. Specific features of radiation from a target of finite thickness include: the boundary photon emission, interference effects for thin target, multi-photon radiation. The theory predictions are compared with experimental data obtained at SLAC and CERN SPS. For electron-positron colliding beams following items are discussed: the separation of coherent and incoherent mechanisms of radiation, the beam-size effect in bremsstrahlung, coherent radiation and mechanisms of electron-positron creation
On theory of π-mesons low-energy scattering on the deuterons
International Nuclear Information System (INIS)
Zubarev, A.L.; Irgaziev, B.F.; Podkopaev, A.P.; Fridman, A.A.
1979-01-01
The pion-deuteron scattering length is calculated using the equations derived by application of Shwinger variational principle to the strongly coupled channel method. The dependence upon the πN-scattering lengths, effective radii and shape of the NN potential is studied. The πN interaction is described by local potentials. The contribution given by closed channels to the πd-scattering length is shown to be of 30 %
Gap length distributions by PEPR
International Nuclear Information System (INIS)
Warszawer, T.N.
1980-01-01
Conditions guaranteeing exponential gap length distributions are formulated and discussed. Exponential gap length distributions of bubble chamber tracks first obtained on a CRT device are presented. Distributions of resulting average gap lengths and their velocity dependence are discussed. (orig.)
Relativistic length agony continued
Directory of Open Access Journals (Sweden)
Redžić D.V.
2014-01-01
Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028
Multi-Scale Scattering Transform in Music Similarity Measuring
Wang, Ruobai
Scattering transform is a Mel-frequency spectrum based, time-deformation stable method, which can be used in evaluating music similarity. Compared with Dynamic time warping, it has better performance in detecting similar audio signals under local time-frequency deformation. Multi-scale scattering means to combine scattering transforms of different window lengths. This paper argues that, multi-scale scattering transform is a good alternative of dynamic time warping in music similarity measuring. We tested the performance of multi-scale scattering transform against other popular methods, with data designed to represent different conditions.
Neutron-Proton Scattering Experiments at ANKE-COSY
Kacharava, A.; Chiladze, D.; Chiladze, B.; Keshelashvili, I.; Lomidze, N.; Macharashvili, G.; McHedlishvili, D.; Nioradze, M.; Rathmann, F.; Ströher, H.; Wilkin, C.
2010-04-01
The nucleon-nucleon interaction (NN) is fundamental for the whole of nuclear physics and hence to the composition of matter as we know it. It has been demonstrated that stored, polarised beams and polarised internal targets are experimental tools of choice to probe spin effects in NN-scattering experiments. While the EDDA experiment has dramatically improved the proton-proton date base, information on spin observables in neutron-proton scattering is very incomplete above 800 MeV, resulting in large uncertainties in isoscalar n p phase shifts. Experiments at COSY, using a polarised deuteron beam or target, can lead to significant improvements in the situation through the study of quasi-free reactions on the neutron in the deuteron. Such a measurements has already been started at ANKE by using polarised deuterons on an unpolarised target to study the dp → ppn deuteron charge-exchange reaction and the full program with a polarised storage cell target just has been conducted. At low excitation energies of the final pp system, the spin observables are directly related to the spin- dependent parts of the neutron-proton charge-exchange amplitudes. Our measurement of the deuteron-proton spin correlations will allow us to determine the relative phases of these amplitudes in addition to their overall magnitudes.
Large acceptance magnetic spectrometers for polarized deep inelastic electron scattering
International Nuclear Information System (INIS)
Petratos, G.G.; Eisele, R.L.; Gearhart, R.A.; Hughes, E.W.; Young, C.C.
1991-10-01
The design of two magnetic spectrometers for the measurement of the spin-dependent structure function g 1 n of the neutron and a test of the Bjorken sum rule is described. The measurement will consist of scattering 23 GeV polarized electrons off a polarized 3 He target and detecting scattered electrons of 7 to 18 GeV at 4.5 degree and 7 degree. Each spectrometer is based on two large aperture dipole magnets bending in opposite directions. This ''reverse'' deflection design doubles the solid angle as compared to the conventional design of same direction bends used in previous experiments. Proper choice of the deflection angles and the distance between the two dipoles in each spectrometer allows background photons from radiative processes to reach the detectors only after at least two bounces off the spectrometer vacuum walls, resulting in an expected tolerable background. Each spectrometer is equipped with a pair of Cerenkov detectors, a pair of scintillation hodoscopes and a lead-glass shower calorimeter providing electron and pion identification with angular and momentum resolutions sufficient for the experimental measurement. 7 refs., 8 figs., 1 tab
The equivalent square concept for the head scatter factor based on scatter from flattening filter
International Nuclear Information System (INIS)
Kim, Siyong; Palta, Jatinder R.; Zhu, Timothy C.
1998-01-01
The equivalent field relationship between square and circular fields for the head scatter factor was evaluated at the source plane. The method was based on integrating the head scatter parameter for projected shaped fields in the source plane and finding a field that produced the same ratio of head scatter to primary dose on the central axis. A value of σ/R≅0.9 was obtained, where σ was one-half of the side length of the equivalent square and R was the radius of the circular field. The assumptions were that the equivalent field relationship for head scatter depends primarily on the characteristics of scatter from the flattening filter, and that the differential scatter-to-primary ratio of scatter from the flattening filter decreases linearly with the radius, within the physical radius of the flattening filter. Lam and co-workers showed empirically that the area-to-perimeter ratio formula, when applied to an equivalent square formula at the flattening filter plane, gave an accurate prediction of the head scatter factor. We have analytically investigated the validity of the area-to-perimeter ratio formula. Our results support the fact that the area-to-perimeter ratio formula can also be used as the equivalent field formula for head scatter at the source plane. The equivalent field relationships for wedge and tertiary collimator scatter were also evaluated. (author)
The equivalent square concept for the head scatter factor based on scatter from flattening filter
Energy Technology Data Exchange (ETDEWEB)
Kim, Siyong; Palta, Jatinder R.; Zhu, Timothy C. [Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida (United States)
1998-06-01
The equivalent field relationship between square and circular fields for the head scatter factor was evaluated at the source plane. The method was based on integrating the head scatter parameter for projected shaped fields in the source plane and finding a field that produced the same ratio of head scatter to primary dose on the central axis. A value of {sigma}/R{approx_equal}0.9 was obtained, where {sigma} was one-half of the side length of the equivalent square and R was the radius of the circular field. The assumptions were that the equivalent field relationship for head scatter depends primarily on the characteristics of scatter from the flattening filter, and that the differential scatter-to-primary ratio of scatter from the flattening filter decreases linearly with the radius, within the physical radius of the flattening filter. Lam and co-workers showed empirically that the area-to-perimeter ratio formula, when applied to an equivalent square formula at the flattening filter plane, gave an accurate prediction of the head scatter factor. We have analytically investigated the validity of the area-to-perimeter ratio formula. Our results support the fact that the area-to-perimeter ratio formula can also be used as the equivalent field formula for head scatter at the source plane. The equivalent field relationships for wedge and tertiary collimator scatter were also evaluated. (author)
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2010-07-01
The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)
International Nuclear Information System (INIS)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner
2010-01-01
The following topics are dealt with: Neutron sources, neutron properties and elastic scattering, correlation functions measured by scattering experiments, symmetry of crystals, applications of neutron scattering, polarized-neutron scattering and polarization analysis, structural analysis, magnetic and lattice excitation studied by inelastic neutron scattering, macromolecules and self-assembly, dynamics of macromolecules, correlated electrons in complex transition-metal oxides, surfaces, interfaces, and thin films investigated by neutron reflectometry, nanomagnetism. (HSI)
Smarandache, Florentin
2013-09-01
Let's denote by VE the speed of the Earth and byVR the speed of the rocket. Both travel in the same direction on parallel trajectories. We consider the Earth as a moving (at a constant speed VE -VR) spacecraft of almost spherical form, whose radius is r and thus the diameter 2r, and the rocket as standing still. The non-proper length of Earth's diameter, as measured by the astronaut is: L = 2 r√{ 1 -|/VE -VR|2 c2 } rocket! Also, let's assume that the astronaut is laying down in the direction of motion. Therefore, he would also shrink, or he would die!
Directory of Open Access Journals (Sweden)
P. R. Parthasarathy
2001-01-01
Full Text Available The transient solution is obtained analytically using continued fractions for a state-dependent birth-death queue in which potential customers are discouraged by the queue length. This queueing system is then compared with the well-known infinite server queueing system which has the same steady state solution as the model under consideration, whereas their transient solutions are different. A natural measure of speed of convergence of the mean number in the system to its stationarity is also computed.
Phase transitions and neutron scattering
International Nuclear Information System (INIS)
Shirane, G.
1993-01-01
A review is given of recent advances in neutron scattering studies of solid state physics. I have selected the study of a structural phase transition as the best example to demonstrate the power of neutron scattering techniques. Since energy analysis is relatively easy, the dynamical aspects of a transition can be elucidated by the neutron probe. I shall discuss in some detail current experiments on the 100 K transition in SrTiO 3 , the crystal which has been the paradigm of neutron studies of phase transitions for many years. This new experiment attempts to clarify the relation between the neutron central peak, observed in energy scans, and the two length scales observed in recent x-ray diffraction studies where only scans in momentum space are possible. (author)
Plane-wave scattering from half-wave dipole arrays
DEFF Research Database (Denmark)
Jensen, Niels E.
1970-01-01
A matrix equation for determination of plane-wave scattering from arrays of thin short-circuited dipoles of lengths about half a wavelength is derived. Numerical and experimental results are presented for linear, circular, and concentric circular arrays.......A matrix equation for determination of plane-wave scattering from arrays of thin short-circuited dipoles of lengths about half a wavelength is derived. Numerical and experimental results are presented for linear, circular, and concentric circular arrays....
Low-energy scattering data for oxygen
International Nuclear Information System (INIS)
Kopecky, S.; Plompen, A.J.M.
2014-01-01
A survey of literature data of the scattering lengths of oxygen is performed, and these values are compared to low-energy precise total cross-section data. To check the quality of the data and the correctness of the relation between coherent scattering lengths and low-energy total cross-sections the situation is examined first for carbon. A value and uncertainty for the coherent scattering length of oxygen is recommended for use in future evaluations of 16 O. This coherent scattering length is fully consistent with the high-precision, low-energy total cross-section data. The consistency requires the use of a larger uncertainty than claimed in the most accurate cross-section papers. This larger uncertainty is nevertheless very small and well within the requirements of applications of this cross-section. The recommended value is b c ( 16 O) = 5.816±0.015 fm and the associated total cross-section for the neutron-energy range 0.5 to 2 000 eV is 3.765±0.025 b. The stated uncertainties are one standard deviation total uncertainty. (authors)
Semi-analytical solution to arbitrarily shaped beam scattering
Wang, Wenjie; Zhang, Huayong; Sun, Yufa
2017-07-01
Based on the field expansions in terms of appropriate spherical vector wave functions and the method of moments scheme, an exact semi-analytical solution to the scattering of an arbitrarily shaped beam is given. For incidence of a Gaussian beam, zero-order Bessel beam and Hertzian electric dipole radiation, numerical results of the normalized differential scattering cross section are presented to a spheroid and a circular cylinder of finite length, and the scattering properties are analyzed concisely.
π-π scattering in a consistent relativistic quark model
International Nuclear Information System (INIS)
Micu, L.
1977-12-01
Introducing the expression of the interpolating field of a pion as a product of suitable modified free quark fields and of a scalar unquantified field into the LSZ formalism one deduces the vanishing of the exotic amplitudes and of the π-π scattering lengths. The asymptotic vanishing of the elastic π - π scattering amplitude may also be obtained under special requirements. (author)
Elastic ππ scattering to two loops
International Nuclear Information System (INIS)
Bijnens, J.; Colangelo, G.; Gasser, J.; Ecker, G.; Sainio, M.E.
1995-11-01
We evaluate analytically the elastic ππ scattering amplitude to two loops in chiral perturbation theory and give numerical values for the two S-wave scattering lengths and for the phase shift difference δ 0 0 -δ 1 1 . (author)
DISCUS, Neutron Single to Double Scattering Ratio in Inelastic Scattering Experiment by Monte-Carlo
International Nuclear Information System (INIS)
Johnson, M.W.
1993-01-01
1 - Description of problem or function: DISCUS calculates the ratio of once-scattered to twice-scattered neutrons detected in an inelastic neutron scattering experiment. DISCUS also calculates the flux of once-scattered neutrons that would have been observed if there were no absorption in the sample and if, once scattered, the neutron would emerge without further re-scattering or absorption. Three types of sample geometry are used: an infinite flat plate, a finite flat plate or a finite length cylinder. (The infinite flat plate is included for comparison with other multiple scattering programs.) The program may be used for any sample for which the scattering law is of the form S(/Q/, omega). 2 - Method of solution: Monte Carlo with importance sampling is used. Neutrons are 'forced' both into useful angular trajectories, and useful energy bins. Biasing of the collision point according to the point of entry of the neutron into the sample is also utilised. The first and second order scattered neutron fluxes are calculated in independent histories. For twice-scattered neutron histories a square distribution in Q-omega space is used to sample the neutron coming from the first scattering event, whilst biasing is used for the second scattering event. (A square distribution is used so as to obtain reasonable inelastic-inelastic statistics.) 3 - Restrictions on the complexity of the problem: Unlimited number of detectors. Max. size of (Q, omega) matrix is 39*149. Max. number of points in momentum space for the scattering cross section is 199
Scattering and multiple scattering in disordered materials
International Nuclear Information System (INIS)
Weaver, R.L.; Butler, W.H.
1992-01-01
The papers in this section were presented at a joint session of symposium V on Applications of Multiple Scattering Theory and of Symposium P on Disordered Systems. They show that the ideas of scattering theory can help us to understand a very broad class of phenomena
Theory of neutron scattering in disordered alloys
International Nuclear Information System (INIS)
Yussouff, M.; Mookerjee, A.
1984-08-01
A comprehensive theory of thermal neutron scattering in disordered alloys is presented here. We consider in detail the case of substitutional random binary alloy with random changes in mass and force constants; and for all values of the concentration. The cluster CPA formalism in argumented space developed here is free from analytical difficulties for the Green function, performs correct averaging over random atomic scattering lengths and employs a self-consistent medium for the calculations. For easy computation, we describe the graphical representation of the resolvent where the approximation steps can be depicted as closed paths in augmented space. Our results for scattering cross sections, both coherent and incoherent, include new types of terms and these lead to asymmetric line shapes for the coherent scattering. (author)
Stern-Gerlach effect without magnetic-field gradient
International Nuclear Information System (INIS)
Zimmer, O.; Felber, J.; Schaerpf, O.
2001-01-01
The Stern-Gerlach effect is the well-known spin-dependent splitting of a neutral particle beam by a magnetic-field gradient. Guided by the pseudomagnetic analogy, we performed a similar experiment where no magnetic-field gradient is involved. The effect is due to the spin-dependence of neutron scattering from polarised nuclei, i.e. caused by the strong interaction between neutrons and nuclei. The beam splitting is proportional to the nuclear polarisation and to the spin-dependent part of the neutron scattering length. Thus it can be used to measure one of both quantities. (orig.)
Neutron scattering from fractals
DEFF Research Database (Denmark)
Kjems, Jørgen; Freltoft, T.; Richter, D.
1986-01-01
The scattering formalism for fractal structures is presented. Volume fractals are exemplified by silica particle clusters formed either from colloidal suspensions or by flame hydrolysis. The determination of the fractional dimensionality through scattering experiments is reviewed, and recent small...
Scatter from optical components
International Nuclear Information System (INIS)
Stover, J.C.
1989-01-01
This book is covered under the following topics: measurement and analysis techniques; BRDF standards, comparisons, and anomalies; scatter measurement of several materials; scatter from contaminations; and optical system contamination: effects, measurement, and control
Inclusive and semi-inclusive analysis from polarised deep-inelastic muon scattering
International Nuclear Information System (INIS)
Kageya, T.
1999-01-01
We present new results for the spin-dependent structure function on the proton and for the polarised quark distributions in the nucleon from semi-inclusive spin asymmetries. With the inclusive asymmetry from deep inelastic scattering of polarised muons on polarised protons, it is found that the Ellis-Jaffe sum rule is violated. Using our results for Γ d 1 , the Bjorken sum rule is confirmed with an accuracy of about 15%. From semi-inclusive spin asymmetries and SMC inclusive spin asymmetries, we determine the polarised quark distributions of valence u and d quarks to be positive and negative, respectively, while the non-strange sea distribution to be consistent with zero
Electron scattering from tetrahydrofuran
International Nuclear Information System (INIS)
Fuss, M C; Sanz, A G; García, G; Muñoz, A; Oller, J C; Blanco, F; Do, T P T; Brunger, M J; Almeida, D; Limão-Vieira, P
2012-01-01
Electron scattering from Tetrahydrofuran (C 4 H 8 O) was investigated over a wide range of energies. Following a mixed experimental and theoretical approach, total scattering, elastic scattering and ionization cross sections as well as electron energy loss distributions were obtained.
International Nuclear Information System (INIS)
Doll, P.
1990-02-01
Neutron-proton scattering as fundamental interaction process below and above hundred MeV is discussed. Quark model inspired interactions and phenomenological potential models are described. The seminar also indicates the experimental improvements for achieving new precise scattering data. Concluding remarks indicate the relevance of nucleon-nucleon scattering results to finite nuclei. (orig.) [de
Home Page | Facilities | Reference | Software | Conferences | Announcements | Mailing Lists Neutron Scattering Banner Neutron Scattering Software A new portal for neutron scattering has just been established sets KUPLOT: data plotting and fitting software ILL/TAS: Matlab probrams for analyzing triple axis data
International Nuclear Information System (INIS)
Lovesey, S.W.
1987-05-01
The report reviews, at an introductory level, the theory of photon scattering from condensed matter. Magnetic scattering, which arises from first-order relativistic corrections to the Thomson scattering amplitude, is treated in detail and related to the corresponding interaction in the magnetic neutron diffraction amplitude. (author)
Roessli, B.; Böni, P.
2000-01-01
The technique of polarized neutron scattering is reviewed with emphasis on applications. Many examples of the usefulness of the method in various fields of physics are given like the determination of spin density maps, measurement of complex magnetic structures with spherical neutron polarimetry, inelastic neutron scattering and separation of coherent and incoherent scattering with help of the generalized XYZ method.
Resonant Inverse Compton Scattering Spectra from Highly Magnetized Neutron Stars
Wadiasingh, Zorawar; Baring, Matthew G.; Gonthier, Peter L.; Harding, Alice K.
2018-02-01
Hard, nonthermal, persistent pulsed X-ray emission extending between 10 and ∼150 keV has been observed in nearly 10 magnetars. For inner-magnetospheric models of such emission, resonant inverse Compton scattering of soft thermal photons by ultrarelativistic charges is the most efficient production mechanism. We present angle-dependent upscattering spectra and pulsed intensity maps for uncooled, relativistic electrons injected in inner regions of magnetar magnetospheres, calculated using collisional integrals over field loops. Our computations employ a new formulation of the QED Compton scattering cross section in strong magnetic fields that is physically correct for treating important spin-dependent effects in the cyclotron resonance, thereby producing correct photon spectra. The spectral cutoff energies are sensitive to the choices of observer viewing geometry, electron Lorentz factor, and scattering kinematics. We find that electrons with energies ≲15 MeV will emit most of their radiation below 250 keV, consistent with inferred turnovers for magnetar hard X-ray tails. More energetic electrons still emit mostly below 1 MeV, except for viewing perspectives sampling field-line tangents. Pulse profiles may be singly or doubly peaked dependent on viewing geometry, emission locale, and observed energy band. Magnetic pair production and photon splitting will attenuate spectra to hard X-ray energies, suppressing signals in the Fermi-LAT band. The resonant Compton spectra are strongly polarized, suggesting that hard X-ray polarimetry instruments such as X-Calibur, or a future Compton telescope, can prove central to constraining model geometry and physics.
Threshold properties of Veneziano model for ππ, πK, and KK scattering
International Nuclear Information System (INIS)
Wong, N.N.; Kamal, A.N.
1975-01-01
The S and P partial waves are projected out at low energies for ππ, πK, K anti K, and KK scatterings from the Veneziano amplitude. The scattering lengths and the effective ranges are compared with the current-algebra predictions. Using ππ scattering as an example one can project out an arbitrary partial wave
KN scattering in the nonrelativistic quark model
International Nuclear Information System (INIS)
Barnes, F.E.
1995-01-01
KN scattering is of interest as a probe of nuclear structure and, more fundamentally, as a laboratory for the study of nonresonant hadron-hadron interactions. KN is a I theoretically attractive channel because of its simplicity, having only S = 1/2, no one pion exchange contributions and no valence q anti q annihilation. It may therefore be useful for the study of short-ranged quark forces analogous to the NN repulsive core. Since there are two isospin states, comparison of two closely related amplitudes is possible. This contribution reviews the experimental status of S-wave KN scattering and related theoretical studies based on quark-gluon dynamics. The experimental low-energy S-wave phase shift is well established for I = 1, but is not yet well determined for I = 0. The ratio of I = 0 to I = 1 scattering lengths is an interesting number theoretically, and may discriminate between different scattering mechanisms. A measurement of these scattering lengths at DAPHNE would be a useful contribution to low energy hadron physics
Role of electron-electron scattering on spin transport in single layer graphene
Directory of Open Access Journals (Sweden)
Bahniman Ghosh
2014-01-01
Full Text Available In this work, the effect of electron-electron scattering on spin transport in single layer graphene is studied using semi-classical Monte Carlo simulation. The D’yakonov-P’erel mechanism is considered for spin relaxation. It is found that electron-electron scattering causes spin relaxation length to decrease by 35% at 300 K. The reason for this decrease in spin relaxation length is that the ensemble spin is modified upon an e-e collision and also e-e scattering rate is greater than phonon scattering rate at room temperature, which causes change in spin relaxation profile due to electron-electron scattering.
The contribution of neutron scattering to molecular biology
International Nuclear Information System (INIS)
Stuhrmann, H.B.
1983-01-01
About half of the atoms of living cells are hydrogens, and nearly all biological applications of neutron scattering rely on the well-known difference in the scattering lengths of the proton and the deuteron. This introduces us to a wide variety of biological problems, which are related with hydrogen in water, proteins, nucleic acids and lipids. Neutron scattering gives an answer to both structural and dynamical aspects of the system in question. With deuterium labelled samples unambiguous information about molecular structure and motion becomes accessible. The architecture of viruses, cell membranes and gene expressing molecules has become a lot clearer with neutron scattering. (author)
Simulation of isotropic scattering of charged particles by composed potentials
Gerasimov, O Y
2003-01-01
The analytical model of scattering of charged particles by a multicentered adiabatic potential which consists of the long-range Coulomb and short-range potentials is used for the parametrization of experiments of elastic low-energy proton-deuteron scattering. For the energies 2.26-13 MeV, the analytical expressions for the phase scattering function in terms of identical parameters which depend on the lengths and effective radii of proton-proton and proton-neutron scattering and on the effective size of deuteron are obtained. The results are in good qualitative accordance with experiments.
Positron scattering from noble gases future prospects
Energy Technology Data Exchange (ETDEWEB)
Jones, A C L; Caradonna, P; Makochekanwa, C; Slaughter, D S; Sullivan, J P; Buckman, S J [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, Australian National University, Canberra, ACT (Australia); Mitroy, J, E-mail: acj107@rsphysse.anu.edu.a [Faculty of Education Health and Science, Charles Darwin University, NT (Australia)
2009-11-01
Recent results for positron scattering from noble gases over an energy range from 0.5 to 60eV are presented. Measurements include the grand total ({sigma}{sub GT}), Ps formation ({sigma}{sub Ps}) and Grand total - Ps formation (({sigma}{sub GT}-P{sub s}) cross sections. Some preliminary DCS results will also be presented. Work on a formulation of modified effective range theory (MERT) is being undertaken to determine the value of the scattering length which may be useful for identifying a bound state. Plans for experiments on metal atoms will be outlined.
Iterative numerical solution of scattering problems
Energy Technology Data Exchange (ETDEWEB)
Tomio, L; Adhikari, S K
1995-05-01
An iterative Neumann series method, employing a real auxiliary scattering integral equation, is used to calculate scattering lengths and phase shifts for the atomic Yukawa and exponential potentials. For these potentials the original Neumann series diverges. The present iterative method yields results that are far better, in convergence, stability and precision, than other momentum space methods. Accurate result is obtained in both cases with an estimated error of about 1 in 10{sup 10} after some-8-10 iterations. (author). 31 refs, 2 tabs.
Iterative numerical solution of scattering problems
International Nuclear Information System (INIS)
Tomio, L.; Adhikari, S.K.
1995-05-01
An iterative Neumann series method, employing a real auxiliary scattering integral equation, is used to calculate scattering lengths and phase shifts for the atomic Yukawa and exponential potentials. For these potentials the original Neumann series diverges. The present iterative method yields results that are far better, in convergence, stability and precision, than other momentum space methods. Accurate result is obtained in both cases with an estimated error of about 1 in 10 10 after some-8-10 iterations. (author). 31 refs, 2 tabs
Electron-helium scattering in Debye plasmas
International Nuclear Information System (INIS)
Zammit, Mark C.; Fursa, Dmitry V.; Bray, Igor; Janev, R. K.
2011-01-01
Electron-helium scattering in weakly coupled hot-dense (Debye) plasma has been investigated using the convergent close-coupling method. The Yukawa-type Debye-Hueckel potential has been used to describe plasma Coulomb screening effects. Benchmark results are presented for momentum transfer cross sections, excitation, ionization, and total cross sections for scattering from the ground and metastable states of helium. Calculations cover the entire energy range up to 1000 eV for the no screening case and various Debye lengths (5-100 a 0 ). We find that as the screening interaction increases, the excitation and total cross sections decrease, while the total ionization cross sections increase.
Bound coherent and incoherent thermal neutron scattering cross sections of the elements
International Nuclear Information System (INIS)
Sears, V.F.
1982-12-01
An up-to-date table of bound coherent and incoherent thermal neutron scattering cross sections of the elements is presented. Values from two different data sources are calculated and compared. These sources are: (1) the free-atom cross sections listed in the Σbarn bookΣ and (2) the Julich scattering length tables. We also call attention to, and clarify, the confusion that exists in the literature concerning the sign of the imaginary part of the complex scattering length
Calculations of neutron spectra after neutron-neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Crawford, B E [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Stephenson, S L [Gettysburg College, Box 405, Gettysburg, PA 17325 (United States); Howell, C R [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Mitchell, G E [North Carolina State University, Raleigh, NC 27695-8202 (United States); Tornow, W [Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308 (United States); Furman, W I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Lychagin, E V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Muzichka, A Yu [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Nekhaev, G V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Strelkov, A V [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Sharapov, E I [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Shvetsov, V N [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)
2004-09-01
A direct neutron-neutron scattering length, a{sub nn}, measurement with the goal of 3% accuracy (0.5 fm) is under preparation at the aperiodic pulsed reactor YAGUAR. A direct measurement of a{sub nn} will not only help resolve conflicting results of a{sub nn} by indirect means, but also in comparison to the proton-proton scattering length, a{sub pp}, shed light on the charge-symmetry of the nuclear force. We discuss in detail the analysis of the nn-scattering data in terms of a simple analytical expression. We also discuss calibration measurements using the time-of-flight spectra of neutrons scattered on He and Ar gases and the neutron activation technique. In particular, we calculate the neutron velocity and time-of-flight spectra after scattering neutrons on neutrons and after scattering neutrons on He and Ar atoms for the proposed experimental geometry, using a realistic neutron flux spectrum-Maxwellian plus epithermal tail. The shape of the neutron spectrum after scattering is appreciably different from the initial spectrum, due to collisions between thermal-thermal and thermal-epithermal neutrons. At the same time, the integral over the Maxwellian part of the realistic scattering spectrum differs by only about 6 per cent from that of a pure Maxwellian nn-scattering spectrum.
Dressing effects on the occurrence scattering time retardation and advance in a dusty plasma
Lee, Myoung-Jae; Jung, Young-Dae; Hanyang Plasma Team
2017-10-01
The dressing effects on the occurrence scattering time for the dust-dust interaction are investigated in a complex plasma. The first-order eikonal analysis is applied to obtain the scattering amplitude and the occurrence scattering time for the dust-dust interaction. The result shows that dressing effect enhances the retardation phenomena of the occurrence scattering time in the forward scattering domain. It is shown that the oscillatory behavior of the scaled occurrence scattering time is getting more significant with an increase of the Debye length. It is also found that the retardation domain of the occurrence scattering time increases with a decrease of the Debye length. The variation of the occurrence scattering time retardation and advance due to the dressing effect is also discussed.
Anomalous and resonance small-angle scattering
International Nuclear Information System (INIS)
Epperson, J.E.; Thiyagarajan, P.
1988-01-01
Significant changes in the small-angle scattered intensity can be induced by making measurements with radiation close to an absorption edge of an appropriate atomic species contained in the sample. These changes can be related quantitatively to the real and imaginary anomalous-dispersion terms for the scattering factor (X-rays) or scattering length (neutrons). The physics inherent in these anomalous-dispersion terms is first discussed before consideration of how they enter the relevant scattering theory. Two major areas of anomalous-scattering research have emerged; macromolecules in solution and unmixing of metallic alloys. Research in each area is reviewed, illustrating both the feasibility and potential of these techniques. All the experimental results reported to date have been obtained with X-rays. However, it is pointed out that the formalism is the same for the analog experiment with neutrons, and a number of suitable isotopes exist which exhibit resonance in an accessible range of energy. Potential applications of resonance small-angle neutron scattering are discussed. (orig.)
International Nuclear Information System (INIS)
Jayaswal, B.; Mazumder, S.
1998-09-01
Small-angle scattering data from strong scattering systems, e.g. porous materials, cannot be analysed invoking single scattering approximation as specimen needed to replicate the bulk matrix in essential properties are too thick to validate the approximation. The presence of multiple scattering is indicated by invalidity of the functional invariance property of the observed scattering profile with variation of sample thickness and/or wave length of the probing radiation. This article delineates how non accounting of multiple scattering affects the results of analysis and then how to correct the data for its effect. It deals with an algorithm to extract single scattering profile from small-angle scattering data affected by multiple scattering. The algorithm can process the scattering data and deduce single scattering profile in absolute scale. A software package, SIMSAS, is introduced for executing this inversion step. This package is useful both to simulate and to analyse multiple small-angle scattering data. (author)
The screening length of interatomic potential in atomic collisions
International Nuclear Information System (INIS)
Yamamura, Y.; Takeuchi, W.; Kawamura, T.
1998-03-01
In computer studies on the interaction of charged particle with solids, many authors treat the nuclear collision by the Thomas-Fermi screened Coulomb potential. For better agreement with experiment, the screening length is modified sometimes. We investigate the theoretical background for the correction factor of the screening length in the interatomic potential which can be deduced from two steps. The first step is to select the correction factor of an isolated atom so as to match the average radius of the Thomas-Fermi electron distribution with that of the Hartree-Fock electron distribution, where we use the Clementi and Roetti's table. The second step is to determine the correction factor of the screening length of the interatomic potential by using a combination rule. The correction factors obtained for the screening length are in good agreement with those determined by the computer analysis of the Impact Collision Ion Scattering Spectroscopy (ICISS) data. (author)
Scattering with polarized neutrons
International Nuclear Information System (INIS)
Schweizer, J.
2007-01-01
In the history of neutron scattering, it was shown very soon that the use of polarized neutron beams brings much more information than usual scattering with unpolarized neutrons. We shall develop here the different scattering methods that imply polarized neutrons: 1) polarized beams without polarization analysis, the flipping ratio method; 2) polarized beams with a uniaxial polarization analysis; 3) polarized beams with a spherical polarization analysis. For all these scattering methods, we shall give examples of the physical problems which can been solved by these methods, particularly in the field of magnetism: investigation of complex magnetic structures, investigation of spin or magnetization densities in metals, insulators and molecular compounds, separation of magnetic and nuclear scattering, investigation of magnetic properties of liquids and amorphous materials and even, for non magnetic material, separation between coherent and incoherent scattering. (author)
Model independence of scattering of three identical bosons in two dimensions
International Nuclear Information System (INIS)
Adhikari, S.K.; Tomio, L.; Delfino, A.; Frederico, T.
1992-05-01
Within the framework of scattering integral equations in momentum space we present numerical results of scattering of three-identical bosons at low energies in two dimensions for short-range separable potentials. An analysis of the present numerical results reveal the three-particle scattering observables to be independent of potential shape provided the low-energy two-particle binding energy and scattering length are held fixed throughout the investigation. (author)
Neutron scattering and magnetism
International Nuclear Information System (INIS)
Mackintosh, A.R.
1983-01-01
Those properties of the neutron which make it a unique tool for the study of magnetism are described. The scattering of neutrons by magnetic solids is briefly reviewed, with emphasis on the information on the magnetic structure and dynamics which is inherent in the scattering cross-section. The contribution of neutron scattering to our understanding of magnetic ordering, excitations and phase transitions is illustrated by experimental results on a variety of magnetic crystals. (author)
Stationary theory of scattering
International Nuclear Information System (INIS)
Kato, T.
1977-01-01
A variant of the stationary methods is described, and it is shown that it is useful in a wide range of problems, including scattering, by long-range potentials, two-space scattering, and multichannel scattering. The method is based on the notion of spectral forms. The paper is restricted to the simplest case of continuous spectral forms defined on a Banach space embedded in the basic Hilbert space. (P.D.)
Introduction to neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Fischer, W E [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1996-11-01
We give here an introduction to the theoretical principles of neutron scattering. The relationship between scattering- and correlation-functions is particularly emphasized. Within the framework of linear response theory (justified by the weakness of the basic interaction) the relation between fluctuation and dissipation is discussed. This general framework explains the particular power of neutron scattering as an experimental method. (author) 4 figs., 4 refs.
International Nuclear Information System (INIS)
Futterman, J.A.H.; Handler, F.A.; Matzner, R.A.
1987-01-01
This book provides a comprehensive treatment of the propagation of waves in the presence of black holes. While emphasizing intuitive physical thinking in their treatment of the techniques of analysis of scattering, the authors also include chapters on the rigorous mathematical development of the subject. Introducing the concepts of scattering by considering the simplest, scalar wave case of scattering by a spherical (Schwarzschild) black hole, the book then develops the formalism of spin weighted spheroidal harmonics and of plane wave representations for neutrino, electromagnetic, and gravitational scattering. Details and results of numerical computations are given. The techniques involved have important applications (references are given) in acoustical and radar imaging
Wu Ta You
1962-01-01
This volume addresses the broad formal aspects and applications of the quantum theory of scattering in atomic and nuclear collisions. An encyclopedic source of pioneering work, it serves as a text for students and a reference for professionals in the fields of chemistry, physics, and astrophysics. The self-contained treatment begins with the general theory of scattering of a particle by a central field. Subsequent chapters explore particle scattering by a non-central field, collisions between composite particles, the time-dependent theory of scattering, and nuclear reactions. An examinati
Cross plane scattering correction
International Nuclear Information System (INIS)
Shao, L.; Karp, J.S.
1990-01-01
Most previous scattering correction techniques for PET are based on assumptions made for a single transaxial plane and are independent of axial variations. These techniques will incorrectly estimate the scattering fraction for volumetric PET imaging systems since they do not take the cross-plane scattering into account. In this paper, the authors propose a new point source scattering deconvolution method (2-D). The cross-plane scattering is incorporated into the algorithm by modeling a scattering point source function. In the model, the scattering dependence both on axial and transaxial directions is reflected in the exponential fitting parameters and these parameters are directly estimated from a limited number of measured point response functions. The authors' results comparing the standard in-plane point source deconvolution to the authors' cross-plane source deconvolution show that for a small source, the former technique overestimates the scatter fraction in the plane of the source and underestimate the scatter fraction in adjacent planes. In addition, the authors also propose a simple approximation technique for deconvolution
Ultrasound scatter in heterogeneous 3D microstructures: Parameters affecting multiple scattering
Engle, B. J.; Roberts, R. A.; Grandin, R. J.
2018-04-01
This paper reports on a computational study of ultrasound propagation in heterogeneous metal microstructures. Random spatial fluctuations in elastic properties over a range of length scales relative to ultrasound wavelength can give rise to scatter-induced attenuation, backscatter noise, and phase front aberration. It is of interest to quantify the dependence of these phenomena on the microstructure parameters, for the purpose of quantifying deleterious consequences on flaw detectability, and for the purpose of material characterization. Valuable tools for estimation of microstructure parameters (e.g. grain size) through analysis of ultrasound backscatter have been developed based on approximate weak-scattering models. While useful, it is understood that these tools display inherent inaccuracy when multiple scattering phenomena significantly contribute to the measurement. It is the goal of this work to supplement weak scattering model predictions with corrections derived through application of an exact computational scattering model to explicitly prescribed microstructures. The scattering problem is formulated as a volume integral equation (VIE) displaying a convolutional Green-function-derived kernel. The VIE is solved iteratively employing FFT-based con-volution. Realizations of random microstructures are specified on the micron scale using statistical property descriptions (e.g. grain size and orientation distributions), which are then spatially filtered to provide rigorously equivalent scattering media on a length scale relevant to ultrasound propagation. Scattering responses from ensembles of media representations are averaged to obtain mean and variance of quantities such as attenuation and backscatter noise levels, as a function of microstructure descriptors. The computational approach will be summarized, and examples of application will be presented.
A scattering model for rain depolarization
Wiley, P. H.; Stutzman, W. L.; Bostian, C. W.
1973-01-01
A method is presented for calculating the amount of depolarization caused by precipitation for a propagation path. In the model the effects of each scatterer and their interactions are accounted for by using a series of simplifying steps. It is necessary only to know the forward scattering properties of a single scatterer. For the case of rain the results of this model for attenuation, differential phase shift, and cross polarization agree very well with the results of the only other model available, that of differential attenuation and differential phase shift. Calculations presented here show that horizontal polarization is more sensitive to depolarization than is vertical polarization for small rain drop canting angle changes. This effect increases with increasing path length.
Light scattering measurement of sodium polyacrylate products
Lama, Nisha; Norwood, David; Boone, Steven; Massie-Boyer, Valerie
2015-03-01
In the presentation, we will describe the use of a multi-detector HPLC incorporating the DAWN EOS multi-angle laser light scattering (MALLS) detector to measure the properties such as molecular weight, RMS radius, contour and persistence length and polydispersity of sodium polyacrylate products. The samples of sodium polyacrylate are used in various industries as thickening agents, coating dispersants, artificial snow, laundry detergent and disposable diapers. Data and results obtained from the experiment will be presented.
Modelling Hyperboloid Sound Scattering
DEFF Research Database (Denmark)
Burry, Jane; Davis, Daniel; Peters, Brady
2011-01-01
The Responsive Acoustic Surfaces workshop project described here sought new understandings about the interaction between geometry and sound in the arena of sound scattering. This paper reports on the challenges associated with modelling, simulating, fabricating and measuring this phenomenon using...... both physical and digital models at three distinct scales. The results suggest hyperboloid geometry, while difficult to fabricate, facilitates sound scattering....
Concentric layered Hermite scatterers
Astheimer, Jeffrey P.; Parker, Kevin J.
2018-05-01
The long wavelength limit of scattering from spheres has a rich history in optics, electromagnetics, and acoustics. Recently it was shown that a common integral kernel pertains to formulations of weak spherical scatterers in both acoustics and electromagnetic regimes. Furthermore, the relationship between backscattered amplitude and wavenumber k was shown to follow power laws higher than the Rayleigh scattering k2 power law, when the inhomogeneity had a material composition that conformed to a Gaussian weighted Hermite polynomial. Although this class of scatterers, called Hermite scatterers, are plausible, it may be simpler to manufacture scatterers with a core surrounded by one or more layers. In this case the inhomogeneous material property conforms to a piecewise continuous constant function. We demonstrate that the necessary and sufficient conditions for supra-Rayleigh scattering power laws in this case can be stated simply by considering moments of the inhomogeneous function and its spatial transform. This development opens an additional path for construction of, and use of scatterers with unique power law behavior.
Binding and Pauli principle corrections in subthreshold pion-nucleus scattering
International Nuclear Information System (INIS)
Kam, J. de
1981-01-01
In this investigation I develop a three-body model for the single scattering optical potential in which the nucleon binding and the Pauli principle are accounted for. A unitarity pole approximation is used for the nucleon-core interaction. Calculations are presented for the π- 4 He elastic scattering cross sections at energies below the inelastic threshold and for the real part of the π- 4 He scattering length by solving the three-body equations. Off-shell kinematics and the Pauli principle are carefully taken into account. The binding correction and the Pauli principle correction each have an important effect on the differential cross sections and the scattering length. However, large cancellations occur between these two effects. I find an increase in the π- 4 He scattering length by 100%; an increase in the cross sections by 20-30% and shift of the minimum in π - - 4 He scattering to forward angles by 10 0 . (orig.)
Introductory theory of neutron scattering
International Nuclear Information System (INIS)
Gunn, J.M.F.
1986-12-01
The paper comprises a set of six lecture notes which were delivered to the summer school on 'Neutron Scattering at a pulsed source', Rutherford Laboratory, United Kingdom, 1986. The lectures concern the physical principles of neutron scattering. The topics of the lectures include: diffraction, incoherent inelastic scattering, connection with the Schroedinger equation, magnetic scattering, coherent inelastic scattering, and surfaces and neutron optics. (UK)
Diffuse scattering of neutrons
International Nuclear Information System (INIS)
Novion, C.H. de.
1981-02-01
The use of neutron scattering to study atomic disorder in metals and alloys is described. The diffuse elastic scattering of neutrons by a perfect crystal lattice leads to a diffraction spectrum with only Bragg spreads. the existence of disorder in the crystal results in intensity and position modifications to these spreads, and above all, to the appearance of a low intensity scatter between Bragg peaks. The elastic scattering of neutrons is treated in this text, i.e. by measuring the number of scattered neutrons having the same energy as the incident neutrons. Such measurements yield information on the static disorder in the crystal and time average fluctuations in composition and atomic displacements [fr
Progress in Long Scale Length Laser-Plasma Interactions
International Nuclear Information System (INIS)
Glenzer, S H; Arnold, P; Bardsley, G; Berger, R L; Bonanno, G; Borger, T; Bower, D E; Bowers, M; Bryant, R; Buckman, S.; Burkhart, S C; Campbell, K; Chrisp, M P; Cohen, B I; Constantin, G; Cooper, F; Cox, J; Dewald, E; Divol, L; Dixit, S; Duncan, J; Eder, D; Edwards, J; Erbert, G; Felker, B; Fornes, J; Frieders, G; Froula, D H; Gardner, S D; Gates, C; Gonzalez, M; Grace, S; Gregori, G; Greenwood, A; Griffith, R; Hall, T; Hammel, B A; Haynam, C; Heestand, G; Henesian, M; Hermes, G; Hinkel, D; Holder, J; Holdner, F; Holtmeier, G; Hsing, W; Huber, S; James, T; Johnson, S; Jones, O S; Kalantar, D; Kamperschroer, J H; Kauffman, R; Kelleher, T; Knight, J; Kirkwood, R K; Kruer, W L; Labiak, W; Landen, O L; Langdon, A B; Langer, S; Latray, D; Lee, A; Lee, F D; Lund, D; MacGowan, B; Marshall, S; McBride, J; McCarville, T; McGrew, L; Mackinnon, A J; Mahavandi, S; Manes, K; Marshall, C; Mertens, E; Meezan, N; Miller, G; Montelongo, S; Moody, J D; Moses, E; Munro, D; Murray, J; Neumann, J; Newton, M; Ng, E; Niemann, C; Nikitin, A; Opsahl, P; Padilla, E; Parham, T; Parrish, G; Petty, C; Polk, M; Powell, C; Reinbachs, I; Rekow, V; Rinnert, R; Riordan, B; Rhodes, M.
2003-01-01
The first experiments on the National Ignition Facility (NIF) have employed the first four beams to measure propagation and laser backscattering losses in large ignition-size plasmas. Gas-filled targets between 2 mm and 7 mm length have been heated from one side by overlapping the focal spots of the four beams from one quad operated at 351 nm (3ω) with a total intensity of 2 x 10 15 W cm -2 . The targets were filled with 1 atm of CO 2 producing of up to 7 mm long homogeneously heated plasmas with densities of n e = 6 x 10 20 cm -3 and temperatures of T e = 2 keV. The high energy in a NIF quad of beams of 16kJ, illuminating the target from one direction, creates unique conditions for the study of laser plasma interactions at scale lengths not previously accessible. The propagation through the large-scale plasma was measured with a gated x-ray imager that was filtered for 3.5 keV x rays. These data indicate that the beams interact with the full length of this ignition-scale plasma during the last ∼1 ns of the experiment. During that time, the full aperture measurements of the stimulated Brillouin scattering and stimulated Raman scattering show scattering into the four focusing lenses of 6% for the smallest length (∼2 mm). increasing to 12% for ∼7 mm. These results demonstrate the NIF experimental capabilities and further provide a benchmark for three-dimensional modeling of the laser-plasma interactions at ignition-size scale lengths
Inelastic Light Scattering Processes
Fouche, Daniel G.; Chang, Richard K.
1973-01-01
Five different inelastic light scattering processes will be denoted by, ordinary Raman scattering (ORS), resonance Raman scattering (RRS), off-resonance fluorescence (ORF), resonance fluorescence (RF), and broad fluorescence (BF). A distinction between fluorescence (including ORF and RF) and Raman scattering (including ORS and RRS) will be made in terms of the number of intermediate molecular states which contribute significantly to the scattered amplitude, and not in terms of excited state lifetimes or virtual versus real processes. The theory of these processes will be reviewed, including the effects of pressure, laser wavelength, and laser spectral distribution on the scattered intensity. The application of these processes to the remote sensing of atmospheric pollutants will be discussed briefly. It will be pointed out that the poor sensitivity of the ORS technique cannot be increased by going toward resonance without also compromising the advantages it has over the RF technique. Experimental results on inelastic light scattering from I(sub 2) vapor will be presented. As a single longitudinal mode 5145 A argon-ion laser line was tuned away from an I(sub 2) absorption line, the scattering was observed to change from RF to ORF. The basis, of the distinction is the different pressure dependence of the scattered intensity. Nearly three orders of magnitude enhancement of the scattered intensity was measured in going from ORF to RF. Forty-seven overtones were observed and their relative intensities measured. The ORF cross section of I(sub 2) compared to the ORS cross section of N2 was found to be 3 x 10(exp 6), with I(sub 2) at its room temperature vapor pressure.
Rayleigh scattering and depolarization ratio in linear alkylbenzene
International Nuclear Information System (INIS)
Liu, Qian; Zhou, Xiang; Huang, Wenqian; Zhang, Yuning; Wu, Wenjie; Luo, Wentai; Yu, Miao; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang
2015-01-01
It is planned to use linear alkylbenzene (LAB) as the organic solvent for the Jiangmen Underground Neutrino Observatory (JUNO) liquid scintillator detectors, due to its ultra-transparency. However, the current Rayleigh scattering length calculation for LAB disagrees with the experimental measurement. This paper reports for the first time that the Rayleigh scattering of LAB is anisotropic, with a depolarization ratio of 0.31±0.01(stat.)±0.01(sys.). We use an indirect method for Rayleigh scattering measurement with the Einstein–Smoluchowski–Cabannes formula, and the Rayleigh scattering length of LAB is determined to be 28.2±1.0 m at 430 nm
Neutron scattering study of dilute supercritical solutions
International Nuclear Information System (INIS)
Cochran, H.D.; Wignall, G.D.; Shah, V.M.; Londono, J.D.; Bienkowski, P.R.
1994-01-01
Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope 36 Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast
Neutron spin echo scattering angle measurement (SESAME)
International Nuclear Information System (INIS)
Pynn, R.; Fitzsimmons, M.R.; Fritzsche, H.; Gierlings, M.; Major, J.; Jason, A.
2005-01-01
We describe experiments in which the neutron spin echo technique is used to measure neutron scattering angles. We have implemented the technique, dubbed spin echo scattering angle measurement (SESAME), using thin films of Permalloy electrodeposited on silicon wafers as sources of the magnetic fields within which neutron spins precess. With 30-μm-thick films we resolve neutron scattering angles to about 0.02 deg. with neutrons of 4.66 A wavelength. This allows us to probe correlation lengths up to 200 nm in an application to small angle neutron scattering. We also demonstrate that SESAME can be used to separate specular and diffuse neutron reflection from surfaces at grazing incidence. In both of these cases, SESAME can make measurements at higher neutron intensity than is available with conventional methods because the angular resolution achieved is independent of the divergence of the neutron beam. Finally, we discuss the conditions under which SESAME might be used to probe in-plane structure in thin films and show that the method has advantages for incident neutron angles close to the critical angle because multiple scattering is automatically accounted for
Light scattering studies at UNICAMP
International Nuclear Information System (INIS)
Luzzi, R.; Cerdeira, H.A.; Salzberg, J.; Vasconcellos, A.R.; Frota Pessoa, S.; Reis, F.G. dos; Ferrari, C.A.; Algarte, C.A.S.; Tenan, M.A.
1975-01-01
Current theoretical studies on light scattering spectroscopy at UNICAMP is presented briefly, such as: inelastic scattering of radiation from a solid state plasma; resonant Ramman scattering; high excitation effects; saturated semiconductors and glasses
Virtual neutron scattering experiments
DEFF Research Database (Denmark)
Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael
2017-01-01
. In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus......We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering...
Scattering on magnetic monopoles
International Nuclear Information System (INIS)
Petry, H.R.
1980-01-01
The time-dependent scattering theory of charged particles on magnetic monopoles is investigated within a mathematical frame-work, which duely pays attention to the fact that the wavefunctions of the scattered particles are sections in a non-trivial complex line-bundle. It is found that Moeller operators have to be defined in a way which takes into account the peculiar long-range behaviour of the monopole field. Formulas for the scattering matrix and the differential cross-section are derived, and, as a by-product, a momentum space picture for particles, which are described by sections in the underlying complex line-bundle, is presented. (orig.)
Deep inelastic neutron scattering
International Nuclear Information System (INIS)
Mayers, J.
1989-03-01
The report is based on an invited talk given at a conference on ''Neutron Scattering at ISIS: Recent Highlights in Condensed Matter Research'', which was held in Rome, 1988, and is intended as an introduction to the techniques of Deep Inelastic Neutron Scattering. The subject is discussed under the following topic headings:- the impulse approximation I.A., scaling behaviour, kinematical consequences of energy and momentum conservation, examples of measurements, derivation of the I.A., the I.A. in a harmonic system, and validity of the I.A. in neutron scattering. (U.K.)
Optimum track fitting in the presence of multiple scattering
International Nuclear Information System (INIS)
Lutz, G.
1987-06-01
A method for track fitting is proposed which attempts to be as close as possible to the real track along the full path length. This is done by the introduction of scattering planes in which the particle is allowed to change its direction. A fit over the full track length includes the probability of direction change by scattering. Using matrix notation a fairly simple formalism for error estimation has been developed. Results of this method are compared to those of more widely used procedures for 'typical' examples of High Energy Spectrometers. (orig.)
Anisotropy of relativistic lepton coherent scattering at axial channeling
International Nuclear Information System (INIS)
Telegin, V.I.; Kanloev, A.M.; Kungurov, F.R.
1989-01-01
The contribution of the coherent and incoherent scattering of relativistic leptons passed through thin crystals in the channeling mode to their angular distribution is considered. The investigation was carried out by numerical integration of the motion equations for a great number of particles. It is shown that in the crystals with a thickness smaller than the dechanneling length the determining role in formation of distribution over the axit angles is played by the coherent scattering of particles by atomic chains. The effect of the multiple scattering on the angular distribution is negligibly small. 6 refs.; 4 figs
Mani, Arjun; Benjamin, Colin
2016-04-13
On the surface of 2D topological insulators, 1D quantum spin Hall (QSH) edge modes occur with Dirac-like dispersion. Unlike quantum Hall (QH) edge modes, which occur at high magnetic fields in 2D electron gases, the occurrence of QSH edge modes is due to spin-orbit scattering in the bulk of the material. These QSH edge modes are spin-dependent, and chiral-opposite spins move in opposing directions. Electronic spin has a larger decoherence and relaxation time than charge. In view of this, it is expected that QSH edge modes will be more robust to disorder and inelastic scattering than QH edge modes, which are charge-dependent and spin-unpolarized. However, we notice no such advantage accrues in QSH edge modes when subjected to the same degree of contact disorder and/or inelastic scattering in similar setups as QH edge modes. In fact we observe that QSH edge modes are more susceptible to inelastic scattering and contact disorder than QH edge modes. Furthermore, while a single disordered contact has no effect on QH edge modes, it leads to a finite charge Hall current in the case of QSH edge modes, and thus a vanishing of the pure QSH effect. For more than a single disordered contact while QH states continue to remain immune to disorder, QSH edge modes become more susceptible--the Hall resistance for the QSH effect changes sign with increasing disorder. In the case of many disordered contacts with inelastic scattering included, while quantization of Hall edge modes holds, for QSH edge modes a finite charge Hall current still flows. For QSH edge modes in the inelastic scattering regime we distinguish between two cases: with spin-flip and without spin-flip scattering. Finally, while asymmetry in sample geometry can have a deleterious effect in the QSH case, it has no impact in the QH case.
International Nuclear Information System (INIS)
Mani, Arjun; Benjamin, Colin
2016-01-01
On the surface of 2D topological insulators, 1D quantum spin Hall (QSH) edge modes occur with Dirac-like dispersion. Unlike quantum Hall (QH) edge modes, which occur at high magnetic fields in 2D electron gases, the occurrence of QSH edge modes is due to spin–orbit scattering in the bulk of the material. These QSH edge modes are spin-dependent, and chiral-opposite spins move in opposing directions. Electronic spin has a larger decoherence and relaxation time than charge. In view of this, it is expected that QSH edge modes will be more robust to disorder and inelastic scattering than QH edge modes, which are charge-dependent and spin-unpolarized. However, we notice no such advantage accrues in QSH edge modes when subjected to the same degree of contact disorder and/or inelastic scattering in similar setups as QH edge modes. In fact we observe that QSH edge modes are more susceptible to inelastic scattering and contact disorder than QH edge modes. Furthermore, while a single disordered contact has no effect on QH edge modes, it leads to a finite charge Hall current in the case of QSH edge modes, and thus a vanishing of the pure QSH effect. For more than a single disordered contact while QH states continue to remain immune to disorder, QSH edge modes become more susceptible—the Hall resistance for the QSH effect changes sign with increasing disorder. In the case of many disordered contacts with inelastic scattering included, while quantization of Hall edge modes holds, for QSH edge modes a finite charge Hall current still flows. For QSH edge modes in the inelastic scattering regime we distinguish between two cases: with spin-flip and without spin-flip scattering. Finally, while asymmetry in sample geometry can have a deleterious effect in the QSH case, it has no impact in the QH case. (paper)
Electron scattering from pyrimidine
International Nuclear Information System (INIS)
Colmenares, Rafael; Fuss, Martina C; García, Gustavo; Oller, Juan C; Muñoz, Antonio; Blanco, Francisco; Almeida, Diogo; Limão-Vieira, Paulo
2014-01-01
Electron scattering from pyrimidine (C 4 H 4 N 2 ) was investigated over a wide range of energies. Following different experimental and theoretical approaches, total, elastic and ionization cross sections as well as electron energy loss distributions were obtained.
Gravitational Bhabha scattering
International Nuclear Information System (INIS)
Santos, A F; Khanna, Faqir C
2017-01-01
Gravitoelectromagnetism (GEM) as a theory for gravity has been developed similar to the electromagnetic field theory. A weak field approximation of Einstein theory of relativity is similar to GEM. This theory has been quantized. Traditional Bhabha scattering, electron–positron scattering, is based on quantized electrodynamics theory. Usually the amplitude is written in terms of one photon exchange process. With the development of quantized GEM theory, the scattering amplitude will have an additional component based on an exchange of one graviton at the lowest order of perturbation theory. An analysis will provide the relative importance of the two amplitudes for Bhabha scattering. This will allow an analysis of the relative importance of the two amplitudes as the energy of the exchanged particles increases. (paper)
Applied electromagnetic scattering theory
Osipov, Andrey A
2017-01-01
Besides classical applications (radar and stealth, antennas, microwave engineering), scattering and diffraction are enabling phenomena for some emerging research fields (artificial electromagnetic materials or metamaterials, terahertz technologies, electromagnetic aspects of nano-science). This book is a tutorial for advanced students who need to study diffraction theory. The textbook gives fundamental knowledge about scattering and diffraction of electromagnetic waves and provides some working examples of solutions for practical high-frequency scattering and diffraction problems. The book focuses on the most important diffraction effects and mechanisms influencing the scattering process and describes efficient and physically justified simulation methods - physical optics (PO) and the physical theory of diffraction (PTD) - applicable in typical remote sensing scenarios. The material is presented in a comprehensible and logical form, which relates the presented results to the basic principles of electromag...
International Nuclear Information System (INIS)
Tezuka, Hirokazu.
1984-10-01
Scattering of a particle by bound nucleons is discussed. Effects of nucleons that are bound in a nucleus are taken as a structure function. The way how to calculate the structure function is given. (author)
International Nuclear Information System (INIS)
1991-07-01
This collection contains 21 papers on the application and development of LIDAR (Light Detection and Ranging) Thomson scattering techniques for the determination of spatially resolved electron temperature and density in magnetic confinement experiments, particularly tokamaks. Refs, figs and tabs
International Nuclear Information System (INIS)
Peterson, G.A.
1989-01-01
We briefly review some of the motivations, early results, and techniques of magnetic elastic and inelastic electron-nucleus scattering. We then discuss recent results, especially those acquired at high momentum transfers. 50 refs., 19 figs
Deep inelastic lepton scattering
International Nuclear Information System (INIS)
Nachtmann, O.
1977-01-01
Deep inelastic electron (muon) nucleon and neutrino nucleon scattering as well as electron positron annihilation into hadrons are reviewed from a theoretical point of view. The emphasis is placed on comparisons of quantum chromodynamics with the data. (orig.) [de
Small angle neutron scattering
International Nuclear Information System (INIS)
Bernardini, G.; Cherubini, G.; Fioravanti, A.; Olivi, A.
1976-09-01
A method for the analysis of the data derived from neutron small angle scattering measurements has been accomplished in the case of homogeneous particles, starting from the basic theory without making any assumption on the form of particle size distribution function. The experimental scattering curves are interpreted with the aid the computer by means of a proper routine. The parameters obtained are compared with the corresponding ones derived from observations at the transmission electron microscope
Neutron scattering on molten transition metals and on Fe-C melts
International Nuclear Information System (INIS)
Weber, M.
1978-01-01
In order to find out whether short-range order phenomena can be detected in iron-carbon melts, neutron scattering experiments were carried out in molten iron-carbon alloys. The method of isotope substitution, where the natural alloying iron was substituted by a 57 Fe-enriched isotope mixture, helped to increase the ratio between the scattering length of the carbon atoms and that of the iron atoms. The mean coherent scattering length for the isotope mixture which is required for further evaluation of the measurements, was determined in an experiment by measuring the limiting angle for total reflection of neutrons on evaporated films. From this determination of the scattering length, a value for the so far unknown scattering length of the 58 Fe isotope was obtained. The small angle scattering in corrected intensity curves of molten Fe-C alloys was investigated in detail. Scattering experiments in unalloyed Fe, Co, and Ni in the range of small scattering vectors proved that this small-angle scattering effect, which was observed here for the first time, is of magnetic origin. It is caused by short-range spin correlations fluctuating with space and time. [de
Does length or neighborhood size cause the word length effect?
Jalbert, Annie; Neath, Ian; Surprenant, Aimée M
2011-10-01
Jalbert, Neath, Bireta, and Surprenant (2011) suggested that past demonstrations of the word length effect, the finding that words with fewer syllables are recalled better than words with more syllables, included a confound: The short words had more orthographic neighbors than the long words. The experiments reported here test two predictions that would follow if neighborhood size is a more important factor than word length. In Experiment 1, we found that concurrent articulation removed the effect of neighborhood size, just as it removes the effect of word length. Experiment 2 demonstrated that this pattern is also found with nonwords. For Experiment 3, we factorially manipulated length and neighborhood size, and found only effects of the latter. These results are problematic for any theory of memory that includes decay offset by rehearsal, but they are consistent with accounts that include a redintegrative stage that is susceptible to disruption by noise. The results also confirm the importance of lexical and linguistic factors on memory tasks thought to tap short-term memory.
SCAP-82, Single Scattering, Albedo Scattering, Point-Kernel Analysis in Complex Geometry
International Nuclear Information System (INIS)
Disney, R.K.; Vogtman, S.E.
1987-01-01
1 - Description of problem or function: SCAP solves for radiation transport in complex geometries using the single or albedo scatter point kernel method. The program is designed to calculate the neutron or gamma ray radiation level at detector points located within or outside a complex radiation scatter source geometry or a user specified discrete scattering volume. Geometry is describable by zones bounded by intersecting quadratic surfaces within an arbitrary maximum number of boundary surfaces per zone. Anisotropic point sources are describable as pointwise energy dependent distributions of polar angles on a meridian; isotropic point sources may also be specified. The attenuation function for gamma rays is an exponential function on the primary source leg and the scatter leg with a build- up factor approximation to account for multiple scatter on the scat- ter leg. The neutron attenuation function is an exponential function using neutron removal cross sections on the primary source leg and scatter leg. Line or volumetric sources can be represented as a distribution of isotropic point sources, with un-collided line-of-sight attenuation and buildup calculated between each source point and the detector point. 2 - Method of solution: A point kernel method using an anisotropic or isotropic point source representation is used, line-of-sight material attenuation and inverse square spatial attenuation between the source point and scatter points and the scatter points and detector point is employed. A direct summation of individual point source results is obtained. 3 - Restrictions on the complexity of the problem: - The SCAP program is written in complete flexible dimensioning so that no restrictions are imposed on the number of energy groups or geometric zones. The geometric zone description is restricted to zones defined by boundary surfaces defined by the general quadratic equation or one of its degenerate forms. The only restriction in the program is that the total
Keeping disease at arm's length
DEFF Research Database (Denmark)
Lassen, Aske Juul
2015-01-01
active ageing change everyday life with chronic disease, and how do older people combine an active life with a range of chronic diseases? The participants in the study use activities to keep their diseases at arm’s length, and this distancing of disease at the same time enables them to engage in social...... and physical activities at the activity centre. In this way, keeping disease at arm’s length is analysed as an ambiguous health strategy. The article shows the importance of looking into how active ageing is practised, as active ageing seems to work well in the everyday life of the older people by not giving...... emphasis to disease. The article is based on ethnographic fieldwork and uses vignettes of four participants to show how they each keep diseases at arm’s length....
Continuously variable focal length lens
Adams, Bernhard W; Chollet, Matthieu C
2013-12-17
A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.
CEBAF Upgrade Bunch Length Measurements
Energy Technology Data Exchange (ETDEWEB)
Ahmad, Mahmoud [Old Dominion Univ., Norfolk, VA (United States)
2016-05-01
Many accelerators use short electron bunches and measuring the bunch length is important for efficient operations. CEBAF needs a suitable bunch length because bunches that are too long will result in beam interruption to the halls due to excessive energy spread and beam loss. In this work, bunch length is measured by invasive and non-invasive techniques at different beam energies. Two new measurement techniques have been commissioned; a harmonic cavity showed good results compared to expectations from simulation, and a real time interferometer is commissioned and first checkouts were performed. Three other techniques were used for measurements and comparison purposes without modifying the old procedures. Two of them can be used when the beam is not compressed longitudinally while the other one, the synchrotron light monitor, can be used with compressed or uncompressed beam.
Coupled channel theory of pion--deuteron reaction applied to threshold scattering
International Nuclear Information System (INIS)
Mizutani, T.; Koltun, D.S.
1977-01-01
Scattering and absorption of pions by a nuclear target are treated together in a coupled channel theory. The theory is developed explicitly for the problem of pion scattering and absorption by a deuteron. The equations are presented in terms of the integral equations of three-body scattering theory. The method is then applied in an approximate from to calculate the contribution of pion absorption to the scattering length for pion--deuteron scattering. The sensitivity of the calculated results to the model assumptions and approximations is investigated
Kondo length in bosonic lattices
Giuliano, Domenico; Sodano, Pasquale; Trombettoni, Andrea
2017-09-01
Motivated by the fact that the low-energy properties of the Kondo model can be effectively simulated in spin chains, we study the realization of the effect with bond impurities in ultracold bosonic lattices at half filling. After presenting a discussion of the effective theory and of the mapping of the bosonic chain onto a lattice spin Hamiltonian, we provide estimates for the Kondo length as a function of the parameters of the bosonic model. We point out that the Kondo length can be extracted from the integrated real-space correlation functions, which are experimentally accessible quantities in experiments with cold atoms.
Continuous lengths of oxide superconductors
Kroeger, Donald M.; List, III, Frederick A.
2000-01-01
A layered oxide superconductor prepared by depositing a superconductor precursor powder on a continuous length of a first substrate ribbon. A continuous length of a second substrate ribbon is overlaid on the first substrate ribbon. Sufficient pressure is applied to form a bound layered superconductor precursor powder between the first substrate ribbon and the second substrate ribbon. The layered superconductor precursor is then heat treated to establish the oxide superconducting phase. The layered oxide superconductor has a smooth interface between the substrate and the oxide superconductor.
Overview of bunch length measurements
International Nuclear Information System (INIS)
Lumpkin, A. H.
1999-01-01
An overview of particle and photon beam bunch length measurements is presented in the context of free-electron laser (FEL) challenges. Particle-beam peak current is a critical factor in obtaining adequate FEL gain for both oscillators and self-amplified spontaneous emission (SASE) devices. Since measurement of charge is a standard measurement, the bunch length becomes the key issue for ultrashort bunches. Both time-domain and frequency-domain techniques are presented in the context of using electromagnetic radiation over eight orders of magnitude in wavelength. In addition, the measurement of microbunching in a micropulse is addressed
Normal standards for kidney length as measured with US in premature infants
International Nuclear Information System (INIS)
Schlesinger, A.E.; Hedlund, G.L.; Pierson, W.P.; Null, D.M.
1986-01-01
In order to develop normal standards for kidney length in premature infants, the authors measured kidney length by US imaging in 39 (to date) premature infants less than 72 hours old and without known renal disease. Kidney length was compared with four different parameters of body size, including gestational age, birth weight, birth length, and body surface area. Similar standards have been generated previously for normal renal length as measured by US imaging in full-term infants and older children. These standards have proven utility in cases of congenital and acquired disorders that abnormally increase or decrease renal size. Scatter plots of kidney length versus body weight and kidney length versus body surface area conformed well to a logarithmic distribution, with a high correlation coefficient and close-fitting 95% confidence limits (SEE = 2.05)
Gravitational waves from a spinning particle scattered by a relativistic star: Axial mode case
International Nuclear Information System (INIS)
Tominaga, Kazuhiro; Saijo, Motoyuki; Maeda, Kei-ichi
2001-01-01
We use a perturbation method to study gravitational waves from a spinning test particle scattered by a relativistic star. The present analysis is restricted to axial modes. By calculating the energy spectrum, the wave forms, and the total energy and angular momentum of gravitational waves, we analyze the dependence of the emitted gravitational waves on particle spin. For a normal neutron star, the energy spectrum has one broad peak whose characteristic frequency corresponds to the angular velocity at the turning point (a periastron). Since the turning point is determined by the orbital parameter, there exists a dependence of the gravitational wave on particle spin. We find that the total energy of l=2 gravitational waves gets larger as the spin increases in the antiparallel direction to the orbital angular momentum. For an ultracompact star, in addition to such an orbital contribution, we find the quasinormal modes excited by a scattered particle, whose excitation rate to gravitational waves depends on the particle spin. We also discuss the ratio of the total angular momentum to the total energy of gravitational waves and explain its spin dependence
Diet, nutrition and telomere length.
Paul, Ligi
2011-10-01
The ends of human chromosomes are protected by DNA-protein complexes termed telomeres, which prevent the chromosomes from fusing with each other and from being recognized as a double-strand break by DNA repair proteins. Due to the incomplete replication of linear chromosomes by DNA polymerase, telomeric DNA shortens with repeated cell divisions until the telomeres reach a critical length, at which point the cells enter senescence. Telomere length is an indicator of biological aging, and dysfunction of telomeres is linked to age-related pathologies like cardiovascular disease, Parkinson disease, Alzheimer disease and cancer. Telomere length has been shown to be positively associated with nutritional status in human and animal studies. Various nutrients influence telomere length potentially through mechanisms that reflect their role in cellular functions including inflammation, oxidative stress, DNA integrity, DNA methylation and activity of telomerase, the enzyme that adds the telomeric repeats to the ends of the newly synthesized DNA. Copyright © 2011 Elsevier Inc. All rights reserved.
Directory of Open Access Journals (Sweden)
Ben Ruktantichoke
2011-06-01
Full Text Available In this study water flowed through a straight horizontal plastic tube placed at the bottom of a large tank of water. The effect of changing the length of tubing on the velocity of flow was investigated. It was found that the Hagen-Poiseuille Equation is valid when the effect of water entering the tube is accounted for.
Finite length Taylor Couette flow
Streett, C. L.; Hussaini, M. Y.
1987-01-01
Axisymmetric numerical solutions of the unsteady Navier-Stokes equations for flow between concentric rotating cylinders of finite length are obtained by a spectral collocation method. These representative results pertain to two-cell/one-cell exchange process, and are compared with recent experiments.
Measurement of the magneto-optical correlation length in turbid media
Lenke, Ralf; Eisenmann, Christoph; Reinke, Daniel; Maret, Georg
2002-11-01
In multiple light scattering media, magnetic field induced circular birefringence (Faraday effect) influences interference effects such as speckle pattern or coherent backscattering. It was predicted that in the diffusive regime the relevant correlation length with respect to the Faraday rotation l*F differs, in general, from the transport mean free path l*. We have experimentally verified the prediction that the ratio l*F/l* equals 2 for Rayleigh scattering and decreases to 1 with increasing scatterer size. We also discuss the influence of the structure factor on l*F.
Virtual neutron scattering experiments
DEFF Research Database (Denmark)
Overgaard, Julie Hougaard; Bruun, Jesper; May, Michael
2016-01-01
We describe how virtual experiments can be utilized in a learning design that prepares students for hands-on experiments at large-scale facilities. We illustrate the design by showing how virtual experiments are used at the Niels Bohr Institute in a master level course on neutron scattering....... In the last week of the course, students travel to a large-scale neutron scattering facility to perform real neutron scattering experiments. Through student interviews and survey answers, we argue, that the virtual training prepares the students to engage more fruitfully with experiments by letting them focus...... on physics and data rather than the overwhelming instrumentation. We argue that this is because they can transfer their virtual experimental experience to the real-life situation. However, we also find that learning is still situated in the sense that only knowledge of particular experiments is transferred...
Electron scattering off nuclei
International Nuclear Information System (INIS)
Gattone, A.O.
1989-01-01
Two recently developed aspects related to the scattering of electrons off nuclei are presented. On the one hand, a model is introduced which emphasizes the relativistic aspects of the problem in the impulse approximation, by demanding strict maintenance of the algebra of the Poincare group. On the other hand, the second model aims at a more sophisticated description of the nuclear response in the case of collective excitations. Basically, it utilizes the RPA formalism with a new development which enables a more careful treatment of the states in the continuum as is the case for the giant resonances. Applications of both models to the description of elastic scattering, inelastic scattering to discrete levels, giant resonances and the quasi-elastic region are discussed. (Author) [es
Cold moderator scattering kernels
International Nuclear Information System (INIS)
MacFarlane, R.E.
1989-01-01
New thermal-scattering-law files in ENDF format have been developed for solid methane, liquid methane liquid ortho- and para-hydrogen, and liquid ortho- and para-deuterium using up-to-date models that include such effects as incoherent elastic scattering in the solid, diffusion and hindered vibration and rotations in the liquids, and spin correlations for the hydrogen and deuterium. These files were generated with the new LEAPR module of the NJOY Nuclear Data Processing System. Other modules of this system were used to produce cross sections for these moderators in the correct format for the continuous-energy Monte Carlo code (MCNP) being used for cold-moderator-design calculations at the Los Alamos Neutron Scattering Center (LANSCE). 20 refs., 14 figs
Quantum Optical Multiple Scattering
DEFF Research Database (Denmark)
Ott, Johan Raunkjær
. In the first part we use a scattering-matrix formalism combined with results from random-matrix theory to investigate the interference of quantum optical states on a multiple scattering medium. We investigate a single realization of a scattering medium thereby showing that it is possible to create entangled...... states by interference of squeezed beams. Mixing photon states on the single realization also shows that quantum interference naturally arises by interfering quantum states. We further investigate the ensemble averaged transmission properties of the quantized light and see that the induced quantum...... interference survives even after disorder averaging. The quantum interference manifests itself through increased photon correlations. Furthermore, the theoretical description of a measurement procedure is presented. In this work we relate the noise power spectrum of the total transmitted or reflected light...
Energy Technology Data Exchange (ETDEWEB)
ZALIZNYAK,I.A.; LEE,S.H.
2004-07-30
Much of our understanding of the atomic-scale magnetic structure and the dynamical properties of solids and liquids was gained from neutron-scattering studies. Elastic and inelastic neutron spectroscopy provided physicists with an unprecedented, detailed access to spin structures, magnetic-excitation spectra, soft-modes and critical dynamics at magnetic-phase transitions, which is unrivaled by other experimental techniques. Because the neutron has no electric charge, it is an ideal weakly interacting and highly penetrating probe of matter's inner structure and dynamics. Unlike techniques using photon electric fields or charged particles (e.g., electrons, muons) that significantly modify the local electronic environment, neutron spectroscopy allows determination of a material's intrinsic, unperturbed physical properties. The method is not sensitive to extraneous charges, electric fields, and the imperfection of surface layers. Because the neutron is a highly penetrating and non-destructive probe, neutron spectroscopy can probe the microscopic properties of bulk materials (not just their surface layers) and study samples embedded in complex environments, such as cryostats, magnets, and pressure cells, which are essential for understanding the physical origins of magnetic phenomena. Neutron scattering is arguably the most powerful and versatile experimental tool for studying the microscopic properties of the magnetic materials. The magnitude of the cross-section of the neutron magnetic scattering is similar to the cross-section of nuclear scattering by short-range nuclear forces, and is large enough to provide measurable scattering by the ordered magnetic structures and electron spin fluctuations. In the half-a-century or so that has passed since neutron beams with sufficient intensity for scattering applications became available with the advent of the nuclear reactors, they have became indispensable tools for studying a variety of important areas of modern
Gomez, Humberto
2016-06-01
The CHY representation of scattering amplitudes is based on integrals over the moduli space of a punctured sphere. We replace the punctured sphere by a double-cover version. The resulting scattering equations depend on a parameter Λ controlling the opening of a branch cut. The new representation of scattering amplitudes possesses an enhanced redundancy which can be used to fix, modulo branches, the location of four punctures while promoting Λ to a variable. Via residue theorems we show how CHY formulas break up into sums of products of smaller (off-shell) ones times a propagator. This leads to a powerful way of evaluating CHY integrals of generic rational functions, which we call the Λ algorithm.
Electromagnetic scattering theory
Bird, J. F.; Farrell, R. A.
1986-01-01
Electromagnetic scattering theory is discussed with emphasis on the general stochastic variational principle (SVP) and its applications. The stochastic version of the Schwinger-type variational principle is presented, and explicit expressions for its integrals are considered. Results are summarized for scalar wave scattering from a classic rough-surface model and for vector wave scattering from a random dielectric-body model. Also considered are the selection of trial functions and the variational improvement of the Kirchhoff short-wave approximation appropriate to large size-parameters. Other applications of vector field theory discussed include a general vision theory and the analysis of hydromagnetism induced by ocean motion across the geomagnetic field. Levitational force-torque in the magnetic suspension of the disturbance compensation system (DISCOS), now deployed in NOVA satellites, is also analyzed using the developed theory.
Relaxation oscillations in stimulated Raman scattering
International Nuclear Information System (INIS)
Kachen, G.I.; Lowdermilk, W.H.
1977-01-01
Light pulses created by stimulated Raman scattering having been found to exhibit a complex time dependence which resembles relaxation oscillations. A focused laser pulse generated both forward and backward Raman emissions which appeared as a series of pulses with durations much shorter than the incident laser pulse. Time dependence of the Raman emission was observed directly by use of a streak camera. The number of observed pulses increased with the intensity of the incident pulse, while separation of the pulses in time depended on the length of the focal region. Beam focusing was incorporated in the coupled wave equations for stimulated Raman scattering. These rate equations were then solved numerically, and the results are in good qualitative agreement with the experimental observations. The short Raman pulses are created by a process associated with depletion of the incident laser pulse. This process occurs under a broad range of conditions
Interstellar scattering of pulsar radiation. Pt. 1
International Nuclear Information System (INIS)
Backer, D.C.
1975-01-01
An investigation of the intensity fluctuations of 28 pulsars near 0.4 GHz indicates that spectra of interstellar scintillation are consistent with a gaussian shape, that scintillation indices are near unity, and that scintillation bandwidth depends linearly on dispersion measure. Observations at cm wavelengths show that the observer is in the near field of the scattering medium for objects with the lowest dispersion measures, and confirm the step dependence of correlation bandwidth on dispersion measure found by Sutton (1971). The variation of scattering parameters with dispersion measure may indicate that the rms deviation of thermal electron density on the scale of 10 11 cm grows with path length through the galaxy. (orig.) [de
Neutron scattering on partially deuterated polybutadiene
Kahle, S; Monkenbusch, M; Richter, D; Arbe, A; Colmenero, J; Frick, B
2002-01-01
The molecular nature of the secondary relaxation (Johari-Goldstein relaxation) and its relationship with the alpha relaxation is in most cases still unknown. In order to access these processes on a molecular level, it is necessary to obtain spatial information of the relaxation. Through the momentum-transfer dependence of the dynamic structure factor S(Q,t), this information can be provided by quasielastic neutron scattering techniques. The large difference in scattering lengths between hydrogen and deuterium allows us to accentuate specific correlations between atoms in a polymer melt. Here, we report on recent results on a polybutadiene melt, where the double bond was hydrogeneous, while the methylene groups carried deuterons (d4h2-PB). In this way the correlations between the double bonds are emphasised. We will show that the double bond/double bond correlation function, generated in this way, shows the same temperature dependence as the viscosity at higher temperatures at the structure factor peak maximum...
Low-energy pion-nucleon scattering
International Nuclear Information System (INIS)
Gibbs, W.R.; Ai, L.; Kaufmann, W.B.
1998-01-01
An analysis of low-energy charged pion-nucleon data from recent π ± p experiments is presented. From the scattering lengths and the Goldberger-Miyazawa-Oehme (GMO) sum rule we find a value of the pion-nucleon coupling constant of f 2 =0.0756±0.0007. We also find, contrary to most previous analyses, that the scattering volumes for the P 31 and P 13 partial waves are equal, within errors, corresponding to a symmetry found in the Hamiltonian of many theories. For the potential models used, the amplitudes are extrapolated into the subthreshold region to estimate the value of the Σ term. Off-shell amplitudes are also provided. copyright 1998 The American Physical Society
Testing special relativity theory using Compton scattering
International Nuclear Information System (INIS)
Contreras S, H.; Hernandez A, L.; Baltazar R, A.; Escareno J, E.; Mares E, C. A.; Hernandez V, C.; Vega C, H. R.
2010-10-01
The validity of the special relativity theory has been tested using the Compton scattering. Since 1905 several experiments has been carried out to show that time, mass, and length change with the velocity, in this work the Compton scattering has been utilized as a simple way to show the validity to relativity. The work was carried out through Monte Carlo calculations and experiments with different gamma-ray sources and a gamma-ray spectrometer with a 3 x 3 NaI (Tl) detector. The pulse-height spectra were collected and the Compton edge was observed. This information was utilized to determine the relationship between the electron's mass and energy using the Compton -knee- position, the obtained results were contrasted with two collision models between photon and electron, one model was built using the classical physics and another using the special relativity theory. It was found that calculations and experiments results fit to collision model made using the special relativity. (Author)
Neutron scattering. Experiment manuals
Energy Technology Data Exchange (ETDEWEB)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner (eds.)
2010-07-01
The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)
International Nuclear Information System (INIS)
Christillin, P.
1986-01-01
The theory of nuclear Compton scattering is reformulated with explicit consideration of both virtual and real pionic degrees of freedom. The effects due to low-lying nuclear states, to seagull terms, to pion condensation and to the Δ dynamics in the nucleus and their interplay in the different energy regions are examined. It is shown that all corrections to the one-body terms, of diffractive behaviour determined by the nuclear form factor, have an effective two-body character. The possibility of using Compton scattering as a complementary source of information about nuclear dynamics is restressed. (author)
Diffraction in nuclear scattering
International Nuclear Information System (INIS)
Wojciechowski, H.
1986-01-01
The elastic scattering amplitudes for charged and neutral particles have been decomposed into diffractive and refractive parts by splitting the nuclear elastic scattering matrix elements into components responsible for these effects. It has been shown that the pure geometrical diffractive effect which carries no information about the nuclear interaction is always predominant at forward angle of elastic angular distributions. This fact suggests that for strongly absorbed particles only elastic cross section at backward angles, i.e. the refractive cross section, can give us basic information about the central nuclear potential. 12 refs., 4 figs., 1 tab. (author)
Proton nuclear scattering radiography
International Nuclear Information System (INIS)
Saudinos, J.
1982-04-01
Nuclear scattering of protons allows to radiograph objects with specific properties: 3-dimensional radiography, different information as compared to X-ray technique, hydrogen radiography. Furthermore the nuclear scattering radiography (NSR) is a well adapted method to gating techniques allowing the radiography of fast periodic moving objects. Results obtained on phantoms, formalin fixed head and moving object are shown and discussed. The dose delivery is compatible with clinical use, but at the moment, the irradiation time is too long between 1 and 4 hours. Perspectives to make the radiograph faster and to get a practical method are discussed
Slow neutron scattering experiments
International Nuclear Information System (INIS)
Moon, R.M.
1985-01-01
Neutron scattering is a versatile technique that has been successfully applied to condensed-matter physics, biology, polymer science, chemistry, and materials science. The United States lost its leadership role in this field to Western Europe about 10 years ago. Recently, a modest investment in the United States in new facilities and a positive attitude on the part of the national laboratories toward outside users have resulted in a dramatic increase in the number of US scientists involved in neutron scattering research. Plans are being made for investments in new and improved facilities that could return the leadership role to the United States. 23 references, 4 figures, 3 tables
Neutron scattering. Experiment manuals
International Nuclear Information System (INIS)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner
2014-01-01
The following topics are dealt with: The thermal triple-axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot-single-crystal diffractometer HEiDi, the three-axis spectrometer PANDA, the backscattering spectrometer SPHERES, the DNS neutron-polarization analysis, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering at KWS-1 and KWS-2, a very-small-angle neutron scattering diffractometer with focusing mirror, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)
International Nuclear Information System (INIS)
McCarthy, I.E.
1991-07-01
The coupled-channels-optical method has been implemented using two different approximations to the optical potential. The half-on-shell optical potential involves drastic approximations for numerical feasibility but still gives a good semiquantitative description of the effect of uncoupled channels on electron scattering from hydrogen, helium and sodium. The distorted-wave optical potential makes no approximations other than the weak coupling approximation for uncoupled channels. In applications to hydrogen and sodium it shows promise of describing scattering phenomena excellently at all energies. 27 refs., 5 figs
Neutron scattering. Experiment manuals
International Nuclear Information System (INIS)
Brueckel, Thomas; Heger, Gernot; Richter, Dieter; Roth, Georg; Zorn, Reiner
2010-01-01
The following topics are dealt with: The thermal triple axis spectrometer PUMA, the high-resolution powder diffractometer SPODI, the hot single-crystal diffractometer HEiDi for structure analysis with neutrons, the backscattering spectrometer SPHERES, neutron polarization analysis with tht time-of-flight spectrometer DNS, the neutron spin-echo spectrometer J-NSE, small-angle neutron scattering with the KWS-1 and KWS-2 diffractometers, the very-small-angle neutron scattering diffractrometer with focusing mirror KWS-3, the resonance spin-echo spectrometer RESEDA, the reflectometer TREFF, the time-of-flight spectrometer TOFTOF. (HSI)
A national facility for small angle neutron scattering
International Nuclear Information System (INIS)
Buyers, W.J.L.; Katsaras, J.; Mellors, W.; Potter, M.M.; Powell, B.M.; Rogge, R.B.; Root, J.H.; Tennant, D.C.; Tun, Z.
1995-01-01
A world-class small angle neutron scattering (SANS) facility is proposed for Canada. It will provide users from the fields of biology, chemistry, physics, materials science and engineering with a uniquely powerful tool for investigating microstructural properties whose length scales lie in the optical to atomic range. (author). 7 refs
Characterization of porous materials by small-angle scattering
Indian Academy of Sciences (India)
radiation is used in some cases to access large length scale and also to minimize the effect ... For numerous industrial and technological applications, it is often necessary to ... catalytic systems and gas burners require materials to be permeable and to provide ... We have estimated the scattering mean free path L, the.
A national facility for small angle neutron scattering
Energy Technology Data Exchange (ETDEWEB)
Buyers, W J.L.; Katsaras, J; Mellors, W; Potter, M M; Powell, B M; Rogge, R B; Root, J H; Tennant, D C; Tun, Z [Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.; Epand, R; Gaulin, B D [McMaster Univ., Hamilton, ON (Canada)
1995-09-15
A world-class small angle neutron scattering (SANS) facility is proposed for Canada. It will provide users from the fields of biology, chemistry, physics, materials science and engineering with a uniquely powerful tool for investigating microstructural properties whose length scales lie in the optical to atomic range. (author). 7 refs.
Statistical properties of chaotic scattering with one open channel
International Nuclear Information System (INIS)
Izrajlev, F.M.; Saher, D.; Sokolov, V.V.
1993-01-01
The correspondence between statistical properties of decaying states and fluctuations in resonance scattering is studied in a statistical model with one open channel. The model is described by an ensemble of random nonhermitian matrices. The dependence of the correlation length on the coupling parameter both for the S-matrix and the cross-section is studied numerically. 37 refs., 7 figs
Solution structure of a short dna fragment studied by neutron scattering
DEFF Research Database (Denmark)
Lederer, H.; May, R. P.; Kjems, Jørgen
1986-01-01
-DNA. The neutron scattering curve is well fitted by that of a rigid rod with a length of 44 nm and a diameter of 2 nm. The result were confirmed by quasi-elastic light scattering and analytical centrifugation. The neutron measurements in H2O and D2O buffer reveal a cross-sectional in homogeneity not detected by X...
Schwinger variational principle in scattering problems of charged particles on mesic atoms and atoms
International Nuclear Information System (INIS)
Belyaev, V.B.; Zubarev, A.L.; Podkopaev, A.P.
1978-01-01
The Schwinger variational principle is applied to solve the problems of atomic physics. A separable approximation for a Hamiltonian of a bound subsystem is used. The length of e + H-scattering and the elastic p(dμ)-scattering cross section are calculated in the second Born approximation
Directory of Open Access Journals (Sweden)
Eric Costello
2011-01-01
Full Text Available The shape of a cable hanging under its own weight and uniform horizontal tension between two power poles is a catenary. The catenary is a curve which has an equation defined by a hyperbolic cosine function and a scaling factor. The scaling factor for power cables hanging under their own weight is equal to the horizontal tension on the cable divided by the weight of the cable. Both of these values are unknown for this problem. Newton's method was used to approximate the scaling factor and the arc length function to determine the length of the cable. A script was written using the Python programming language in order to quickly perform several iterations of Newton's method to get a good approximation for the scaling factor.
Varghese, Babu; Rajan, Vinayakrishnan; van Leeuwen, Ton; Steenbergen, Wiendelt
2007-01-01
The performance of a graded index multimode fiber optic low coherence Mach-Zehnder interferometer with phase modulation is analyzed. Investigated aspects were its ability to measure path length distributions and to perform path length resolved Doppler measurements of multiple scattered photons in a
Varghese, Babu; Rajan, Vinayakrishnan; van Leeuwen, Ton G.; Steenbergen, Wiendelt
2007-01-01
The performance of a graded index multimode fiber optic low coherence Mach-Zehnder interferometer with phase modulation is analyzed. Investigated aspects were its ability to measure path length distributions and to perform path length resolved Doppler measurements of multiple scattered photons in a
Controlling the scattering properties of thin, particle-doped coatings
Rogers, William; Corbett, Madeleine; Manoharan, Vinothan
2013-03-01
Coatings and thin films of small particles suspended in a matrix possess optical properties that are important in several industries from cosmetics and paints to polymer composites. Many of the most interesting applications require coatings that produce several bulk effects simultaneously, but it is often difficult to rationally formulate materials with these desired optical properties. Here, we focus on the specific challenge of designing a thin colloidal film that maximizes both diffuse and total hemispherical transmission. We demonstrate that these bulk optical properties follow a simple scaling with two microscopic length scales: the scattering and transport mean free paths. Using these length scales and Mie scattering calculations, we generate basic design rules that relate scattering at the single particle level to the film's bulk optical properties. These ideas will be useful in the rational design of future optically active coatings.
Modelling of classical ghost images obtained using scattered light
International Nuclear Information System (INIS)
Crosby, S; Castelletto, S; Aruldoss, C; Scholten, R E; Roberts, A
2007-01-01
The images obtained in ghost imaging with pseudo-thermal light sources are highly dependent on the spatial coherence properties of the incident light. Pseudo-thermal light is often created by reducing the coherence length of a coherent source by passing it through a turbid mixture of scattering spheres. We describe a model for simulating ghost images obtained with such partially coherent light, using a wave-transport model to calculate the influence of the scattering on initially coherent light. The model is able to predict important properties of the pseudo-thermal source, such as the coherence length and the amplitude of the residual unscattered component of the light which influence the resolution and visibility of the final ghost image. We show that the residual ballistic component introduces an additional background in the reconstructed image, and the spatial resolution obtainable depends on the size of the scattering spheres
Small-angle neutron scattering instrument at MINT
International Nuclear Information System (INIS)
Mohd Ali Sufi; Yusof Abdullah; Razali Kassim; Hamid; Shahidan Radiman; Mohammad Deraman; Abdul Ghaffar Ramli
1996-01-01
The Small Angle Neutron Scattering (SANS) Instrument has been developed at Malaysian Institute for Nuclear Technology Research (MINT) for studying structural properties of materials on the length scale 1 nm to 100 nm. This is the length scale which is relevant for many topics within soft condensed matter, like polymers, colloids, biological macromolecules, etc. The SANS is a complementary technique to X-ray and electron scattering. However, while these later techniques give information on structures near surface, SANS concerns the structure of the bulk. Samples studied by SANS technique are typically bulk materials of the sizes mm's to cm's, or materials dissolved in a liquid. This paper described the general characteristics of SANS instrument as well as the experimental formulation in neutron scattering. The preliminary results obtained by this instrument are shown
Modelling of classical ghost images obtained using scattered light
Energy Technology Data Exchange (ETDEWEB)
Crosby, S; Castelletto, S; Aruldoss, C; Scholten, R E; Roberts, A [School of Physics, University of Melbourne, Victoria, 3010 (Australia)
2007-08-15
The images obtained in ghost imaging with pseudo-thermal light sources are highly dependent on the spatial coherence properties of the incident light. Pseudo-thermal light is often created by reducing the coherence length of a coherent source by passing it through a turbid mixture of scattering spheres. We describe a model for simulating ghost images obtained with such partially coherent light, using a wave-transport model to calculate the influence of the scattering on initially coherent light. The model is able to predict important properties of the pseudo-thermal source, such as the coherence length and the amplitude of the residual unscattered component of the light which influence the resolution and visibility of the final ghost image. We show that the residual ballistic component introduces an additional background in the reconstructed image, and the spatial resolution obtainable depends on the size of the scattering spheres.
Minimal Length, Measurability and Gravity
Directory of Open Access Journals (Sweden)
Alexander Shalyt-Margolin
2016-03-01
Full Text Available The present work is a continuation of the previous papers written by the author on the subject. In terms of the measurability (or measurable quantities notion introduced in a minimal length theory, first the consideration is given to a quantum theory in the momentum representation. The same terms are used to consider the Markov gravity model that here illustrates the general approach to studies of gravity in terms of measurable quantities.
International Nuclear Information System (INIS)
Wagner, P.
1976-04-01
Effects on graphite thermal conductivities due to controlled alterations of the graphite structure by impurity addition, porosity, and neutron irradiation are shown to be consistent with the phonon-scattering formulation 1/l = Σ/sub i equals 1/sup/n/ 1/l/sub i/. Observed temperature effects on these doped and irradiated graphites are also explained by this mechanism
International Nuclear Information System (INIS)
Johnson, R.C.
1980-01-01
High energy and small momentum transfer 2 'yields' 2 hadronic scattering processes are described in the physical framework of particle exchange. Particle production in high energy collisions is considered with emphasis on the features of inclusive reactions though with some remarks on exclusive processes. (U.K.)