Measurement of the spin structure of the deuteron at COMPASS

2005 ◽  
Author(s):  
Jürgen Hannappel
Keyword(s):  
Spin Structure

Interaction of ditertiary phosphines with phenyl- and 1-naphthyldithiocarbamatonickel(II)

1985 ◽  
Vol 50 (6) ◽  
pp. 1383-1390
Author(s):  
Aref A. M. Aly ◽  
Ahmed A. Mohamed ◽  
Mahmoud A. Mousa ◽  
Mohamed El-Shabasy
Keyword(s):  
Thermal Analysis ◽  
Powder Diffraction ◽  
Spin Structure ◽  
Magnetic Measurements ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
X Ray ◽  
Square Planar

The synthesis of the following mixed ligand complexes is reported: [Ni(phdtc)2(dpm)2], [Ni(phdtc)2(dpe)2], [Ni(phdtc)2(dpp)3], [Ni(1-naphdtc)2(dpm)2], [Ni(1-naphdtc)2], and [Ni(1-naphdtc)2(dpp)2], where phdtc = PhNHCSS-, 1-naphdtc = 1-NaPhNHCSS-, dpm = Ph2PCH2PPh2, dpe = Ph2P(CH2)2PPh2, and dpp = Ph2P(CH2)3PPh2. The complexes are characterised by microanalysis, IR and UV-Vis spectra, magnetic measurements, conductivity, X-ray powder diffraction, and thermal analysis. All the mixed ligand complexes are diamagnetic, and thus a square-planar or square-pyramidal (low-spin) structure was proposed for the present complexes.

scholarly journals Nothing is certain in string compactifications

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Iñaki García Etxebarria ◽  
Miguel Montero ◽  
Kepa Sousa ◽  
Irene Valenzuela
Keyword(s):  
Flux Compactifications ◽  
Spin Structure ◽  
Energy Condition ◽  
Low Energy ◽  
Type Ii ◽  
String Compactifications ◽  
Compact Dimension ◽  
Bordism Group ◽  
Topological Obstruction ◽  
M Theory

Abstract A bubble of nothing is a spacetime instability where a compact dimension collapses. After nucleation, it expands at the speed of light, leaving “nothing” behind. We argue that the topological and dynamical mechanisms which could protect a compactification against decay to nothing seem to be absent in string compactifications once supersymmetry is broken. The topological obstruction lies in a bordism group and, surprisingly, it can disappear even for a SUSY-compatible spin structure. As a proof of principle, we construct an explicit bubble of nothing for a T3 with completely periodic (SUSY-compatible) spin structure in an Einstein dilaton Gauss-Bonnet theory, which arises in the low-energy limit of certain heterotic and type II flux compactifications. Without the topological protection, supersymmetric compactifications are purely stabilized by a Coleman-deLuccia mechanism, which relies on a certain local energy condition. This is violated in our example by the nonsupersymmetric GB term. In the presence of fluxes this energy condition gets modified and its violation might be related to the Weak Gravity Conjecture.We expect that our techniques can be used to construct a plethora of new bubbles of nothing in any setup where the low-energy bordism group vanishes, including type II compactifications on CY3, AdS flux compactifications on 5-manifolds, and M-theory on 7-manifolds. This lends further evidence to the conjecture that any non-supersymmetric vacuum of quantum gravity is ultimately unstable.

scholarly journals CONSTITUENT QUARKS AND THE SPIN OF THE PROTON

2009 ◽  
Vol 24 (27) ◽  
pp. 2167-2174 ◽  
Author(s):  
H. FRITZSCH ◽  
G. ELDAHOUMI
Keyword(s):  
Internal Structure ◽  
Bound States ◽  
Spin Structure ◽  
Constituent Quark ◽  
Valence Quark

The constituent quarks are interpreted as bound states, which have an internal structure. The quark distributions of the proton are related to those of the constituent quarks. The experiments support this hypothesis. Likewise the spin structure of the proton is related to the spin structure of the constituent quarks. We find that about 30% of the spin of a constituent quark is given by the valence quark, and 70% are provided by the gluons.

Effect of Diamagnetic A2+ Substitution on the Magnetic and Ferroelectric Properties of the Bi1−xAxFeO3 Multiferroics

2007 ◽  
Vol 1034 ◽  
Author(s):  
V. A. Khomchenko ◽  
D. A. Kiselev ◽  
J. M. Vieira ◽  
Li Jian ◽  
A. M. L. Lopes ◽  
...  
Keyword(s):  
Spin Structure ◽  
Ionic Radius ◽  
Ferroelectric Properties ◽  
Piezoresponse Force Microscopy ◽  
Weak Ferromagnetism ◽  
Force Microscopy ◽  
Microscopy Data ◽  
A Site ◽  
Induced Changes ◽  
Spiral Spin

AbstractInvestigation of crystal structure, magnetic and local ferroelectric properties of the diamagnetically-doped Bi1−xAxFeO3 (A= Ca, Sr, Pb, Ba; x= 0.2, 0.3) ceramic samples has been carried out. It has been shown that the solid solutions have a rhombohedrally distorted perovskite structure described by the space group R3c. Piezoresponse force microscopy data have revealed the existence of the spontaneous ferroelectric polarization in the samples at room temperature. Magnetization measurements have shown that the magnetic state of these compounds is determined by the ionic radius of the substituting elements. A-site substitution with the biggest ionic radius ions has been found to suppress the spiral spin structure of BiFeO3 and to result in the appearance of weak ferromagnetism. The magnetic properties have been discussed in terms of doping- induced changes in the magnetic anisotropy.

Quantum transformation of spin structure of a Fe8 nanocluster in ultrastrong magnetic fields

2000 ◽  
Vol 42 (6) ◽  
pp. 1100-1105 ◽  
Author(s):  
A. K. Zvezdin ◽  
V. I. Plis ◽  
A. I. Popov
Keyword(s):  
Magnetic Fields ◽  
Spin Structure
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