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Journal articles on the topic 'Nuclear spin ; Angular momentum (Nuclear physics)'

Author: Grafiati

Published: 4 June 2021

Last updated: 11 February 2022

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1

GUPTA, RAJ K., SHAM S. MALIK, J. S. BATRA, PETER O. HESS, and WERNER SCHEID. "PHENOMENOLOGY OF NUCLEI AT VERY HIGH ANGULAR MOMENTA USING PARAMETRIZED TWO-CENTER NUCLEAR SHAPES." International Journal of Modern Physics E 04, no. 04 (December 1995): 789–800. http://dx.doi.org/10.1142/s0218301395000262.

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The nuclear shapes and variation of moment of inertia with angular momentum, as well as the limiting angular momentum carried by a nucleus at its fissioning stage, are derived from the observed data of the ground-state yrast band and quadrupole deformations of these states. The necking-in of the nuclear shapes are shown to start already at J*~14+−18+. The empirical variation of moment of inertia with angular momentum is found to include the back-bending and forward-bending effects and supports the nuclear softness model of the nucleus. The fission of nuclei is shown to occur at very high angular momenta, which is different for different nuclei. The role of deformation energy is analyzed and the possibility of predicting the quadrupole deformations, or B(E2) transitions, for very high spin states is discussed. The calculations are presented for 156Dy, 158Er, and 164Hf.

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2

Oka, Takeshi. "Nuclear spin selection rules in chemical reactions by angular momentum algebra." Journal of Molecular Spectroscopy 228, no. 2 (December 2004): 635–39. http://dx.doi.org/10.1016/j.jms.2004.08.015.

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3

LAVENDA, B. H. "APPLICATION OF CLASSICAL FORMULATIONS OF QUANTUM MECHANICAL TIME-DEPENDENT VARIATIONAL PRINCIPLES TO THE SHELL AND COLLECTIVE MODELS." International Journal of Modern Physics E 13, no. 02 (April 2004): 451–77. http://dx.doi.org/10.1142/s0218301304002302.

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The pairing off of two-dimensional vortices with opposite orientation and constant strength has its analog in nuclear pairing forces, where the constant vortex strength corresponds to the projection of the angular momentum on the symmetry axis. This occurs as a second-order phase transition for a critical value of the interaction strength. Interactions leading to configurational mixing are analyzed in terms of Euler's equation of an asymmetrical top in the strong coupling limit. The dynamics of pairing forces, configurational mixing, and deformation alignment, due to quadrupole forces and the coupling of the total angular momentum to the intrinsic spin of the odd nucleon, are analyzed by imposing constraints on the coefficients of a quadratic rotational Hamiltonian. Processes leading to deformation alignment give rise to precessional motion of the total angular momentum about the nuclear symmetry axis.

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4

THOMAS, ANTHONY W. "SPIN AND ORBITAL ANGULAR MOMENTUM IN THE PROTON." International Journal of Modern Physics E 18, no. 05n06 (June 2009): 1116–34. http://dx.doi.org/10.1142/s0218301309013403.

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Since the announcement of the proton spin crisis by the European Muon Collaboration there has been considerable progress in unravelling the distribution of spin and orbital angular momentum within the proton. We review the current status of the problem, showing that not only have strong upper limits have been placed on the amount of polarized glue in the proton but that the experimental determination of the spin content has become much more precise. It is now clear that the origin of the discrepancy between experiment and the naive expectation of the fraction of spin carried by the quarks and anti-quarks in the proton lies in the non-perturbative structure of the proton. We explain how the features expected in a modern, relativistic and chirally symmetric description of nucleon structure naturally explain the current data. The consequences of this explanation for the presence of orbital angular momentum on quarks and gluons is reviewed and comparison made with recent results from lattice QCD and experimental data.

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Sasaki, Shigemi, Ian McNulty, and Roger Dejus. "Undulator radiation carrying spin and orbital angular momentum." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 582, no. 1 (November 2007): 43–46. http://dx.doi.org/10.1016/j.nima.2007.08.058.

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6

Leader, Elliot. "A proposed measurement of optical orbital and spin angular momentum and its implications for photon angular momentum." Physics Letters B 779 (April 2018): 385–87. http://dx.doi.org/10.1016/j.physletb.2018.02.029.

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7

ABDULRAHMAN, I., and I. FACHRUDDIN. "A FORMULATION WITHOUT PARTIAL WAVE DECOMPOSITION FOR SCATTERING OF ${\rm SPIN}\hbox{-} \frac{1}{2}$ AND SPIN-0 PARTICLES." Modern Physics Letters A 24, no. 11n13 (April 30, 2009): 843–46. http://dx.doi.org/10.1142/s0217732309000139.

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A new technique has been developed to calculate scattering of [Formula: see text] and spin-0 particles. The so called momentum-helicity basis states are constructed from the helicity and the momentum states, which are not expanded in the angular momentum states. Thus, all angular momentum states are taken into account. Compared with the partial-wave approach this technique will then give more benefit especially in calculations for higher energies. Taking as input a simple spin-orbit potential, the Lippman-Schwinger equations for the T -matrix elements are solved and some observables are calculated.

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8

Naik, H., S. P. Dange, R. J. Singh, and A. V. R. Reddy. "Single-particle spin effect on fission fragment angular momentum." European Physical Journal A 31, no. 2 (February 2007): 195–202. http://dx.doi.org/10.1140/epja/i2006-10171-0.

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9

Ristic, Vladimir, Mirko Radulovic, Tatjana Miladinovic, and Jasna Stevanovic. "Getting deeper insight into stopping power problems in radiation physics using the Noether's theorem corollary." Nuclear Technology and Radiation Protection 29, no. 1 (2014): 24–27. http://dx.doi.org/10.2298/ntrp1401024r.

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The theories that combine two different approaches in dealing with interacting objects, for instance, treating electromagnetic laser field classically, and the interacting atom as a quantum object, have some ambiguities and, as such, they should be labeled as ?mixed?. From the Noether's Theorem Corollary, which we proved earlier, about the conservation laws of energy, momentum and angular momentum in mixed theories, follows that the aforementioned theories do not support the law of angular momentum/spin conservation (to be precise, the obtained result does not imply that the law of conservation of angular momentum and spin is not valid generally, but rather that mixed theories can produce the results which might violate this law). In present paper, an additional explanation following our Corollary is given to why the calculation of the stopping power in the fully quantized theory gives better results than those that were obtained in mixed theories, which further confirms the predictions of our Corollary.

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10

Choi, Taeseung. "Proper relativistic position operators in 1+1 and 2+1 dimensions." International Journal of Modern Physics A 35, no. 18 (June 17, 2020): 2050084. http://dx.doi.org/10.1142/s0217751x20500840.

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We have revisited the Dirac theory in [Formula: see text] and [Formula: see text] dimensions by using the covariant representation of the parity-extended Poincaré group in their native dimensions. The parity operator plays a crucial role in deriving wave equations in both theories. We studied two position operators, a canonical one and a covariant one that becomes the particle position operator projected onto the particle subspace. In [Formula: see text] dimensions the particle position operator, not the canonical position operator, provides the conserved Lorentz generator. The mass moment defined by the canonical position operator needs an additional unphysical spin-like operator to become the conserved Lorentz generator in [Formula: see text] dimensions. In [Formula: see text] dimensions, the sum of the orbital angular momentum given by the canonical position operator and the spin angular momentum becomes a constant of motion. However, orbital and spin angular momentum do not conserve separately. On the other hand the orbital angular momentum given by the particle position operator and its corresponding spin angular momentum become a constant of motion separately.

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11

ANTUNES, A. C. B., and L. J. ANTUNES. "ANGULAR MOMENTUM AND SPIN EFFECTS ON THE DIQUARK FORMATION." International Journal of Modern Physics A 26, no. 07n08 (March 30, 2011): 1295–304. http://dx.doi.org/10.1142/s0217751x11052803.

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Quark interactions inside baryons depend on the spin states of the quarks. We investigated the contribution of the spin–spin interactions of quarks in comparison with other factors necessary for diquark formation in baryons, concluding that the effects of spin–spin interactions are correlated with the state of angular momentum excitation.

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12

Al-Adili, A., A. Solders, and V. Rakopoulos. "Employing TALYS to deduce angular momentum rootmean-square values, Jrms, in fission fragments." EPJ Web of Conferences 239 (2020): 03019. http://dx.doi.org/10.1051/epjconf/202023903019.

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Fission fragments exhibit large angular momenta J, which constitutes a challenge for fission models to fully explain. Systematic measurements of isomeric yield ratios (IYR) are needed for basic nuclear reaction physics and nuclear applications, especially as a function of mass number and excitation energy. One goal is to improve the current understanding of the angular momentum generation and sharing in the fission process. To do so, one needs to improve the modeling of nuclear de-excitation. In this work, we have used the TALYS nuclear-reaction code to relax excited fission fragments and to extract root-mean-square (rms) values of initial spin distributions, after comparison with experimentally determined IYRs. The method was assessed by a comparative study on 252Cf(sf) and 235U(nth,f). The results show a consistent performance of TALYS, both in comparison to reported literature values and to other fission codes. A few discrepant Jrms values were also found. The discrepant literature values could need a second consideration as they could possibly be caused by outdated models. Our TALYS method will be refined to better comply with contemporary sophisticated models and to reexamine older deduced values in literature.

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13

AGGARWAL, MAMTA. "NEUTRON EMISSION SPECTRA AND LEVEL DENSITY OF HOT ROTATING 132Sn." International Journal of Modern Physics E 17, no. 06 (June 2008): 1091–105. http://dx.doi.org/10.1142/s0218301308010295.

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The neutron emission spectrum of the highly excited compound nuclear system 132 Sn is investigated at high spin. The doubly magic nucleus 132 Sn undergoes a shape transition at high angular momentum which affects the nuclear level density and neutron emission probability considerably. The interplay of temperature, shape, deformation and rotational degrees of freedom and their influence on neutron emission is emphasized. We predict an enhancement of nucleonic emission at those spins where the nucleus suffers a transition from a spherical to deformed shape.

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14

ARIK, M., and U. KAYSERILIOGLU. "THE ANTICOMMUTATOR SPIN ALGEBRA, ITS REPRESENTATIONS AND QUANTUM GROUP INVARIANCE." International Journal of Modern Physics A 18, no. 27 (October 30, 2003): 5039–45. http://dx.doi.org/10.1142/s0217751x03015933.

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We define a 3-generator algebra obtained by replacing the commutators with anticommutators in the defining relations of the angular momentum algebra. We show that integer spin representations are in one to one correspondence with those of the angular momentum algebra. The half-integer spin representations, on the other hand, split into two representations of dimension [Formula: see text]. The anticommutator spin algebra is invariant under the action of the quantum group SO q(3) with q=-1.

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15

JI, XIANGDONG. "QUARK ORBITAL ANGULAR MOMENTUM AND GENERALIZED PARTON DISTRIBUTIONS." International Journal of Modern Physics A 18, no. 08 (March 30, 2003): 1303–9. http://dx.doi.org/10.1142/s0217751x03014642.

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16

Ghosh, U. S., B. Mukherjee, and S. Rai. "Shell model study of nuclear structure in 63,65,67Ga." International Journal of Modern Physics E 29, no. 07 (July 2020): 2050045. http://dx.doi.org/10.1142/s0218301320500457.

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Shell model calculations have been performed in [Formula: see text] model space using two different interactions viz. jj44bpn and jun45pn to explore nuclear structure in [Formula: see text]Ga. Calculated excitation energies are compared with previously reported experimental values and a good agreement has been observed. Transitions strengths are also calculated using two sets of effective charges for proton and neutron and are compared with nearby [Formula: see text]Zn isotopes. Occupation probabilities of protons and neutrons corresponding to individual orbitals (namely [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] orbital), and dominant particle configurations for individual spin states have been presented as well. Calculations suggest major role of intruder [Formula: see text] orbital in constructing the wave functions of higher angular momentum states, whereas, the lower excited states are mainly dominated by contributions from [Formula: see text] orbitals.

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17

DELBOURGO, R. "GRASSMANN WAVE FUNCTIONS AND INTRINSIC SPIN." International Journal of Modern Physics A 03, no. 03 (March 1988): 591–602. http://dx.doi.org/10.1142/s0217751x88000242.

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By associating spin angular momentum with Sp(2) transformations on two Grassmann coordinates, we show how one may formulate spinor wave functions in complete analogy to spherical harmonics for orbital momentum. The relativistic generalization requires a doubling of Grassmann coordinates and a connection may be established with the Dirac equation.

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18

JAFFE, ROBERT L. "OPEN QUESTIONS IN HIGH ENERGY SPIN PHYSICS." International Journal of Modern Physics A 18, no. 08 (March 30, 2003): 1141–52. http://dx.doi.org/10.1142/s0217751x03014459.

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I describe a few of the most exciting open questions in high energy spin physics. After a brief look at (g - 2)μ and the muon electric dipole moment, I concentrate on QCD spin physics. Pressing questions include the interpretation of new asymmetries seen in semi-inclusive DIS, measuring the polarized gluon and quark transversity distributions in the nucleon, testing the DHGHY Sum Rule, measuring the orbital angular momentum in the nucleon, and many others which go beyond the space and time allotted for this talk.

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19

VAN ISACKER, P. "NEUTRON–PROTON PAIRS IN NUCLEI." International Journal of Modern Physics E 22, no. 11 (November 2013): 1330028. http://dx.doi.org/10.1142/s0218301313300282.

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A review is given of attempts to describe nuclear properties in terms of neutron–proton pairs that are subsequently replaced by bosons. Some of the standard approaches with low-spin pairs are recalled but the emphasis is on a recently proposed framework with pairs of neutrons and protons with aligned angular momentum. The analysis is carried out for general j and applied to N=Z nuclei in the 1f7/2 and 1g9/2 shells.

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20

MARIS, PIETER, and JAMES P. VARY. "AB INITIO NUCLEAR STRUCTURE CALCULATIONS OF p-SHELL NUCLEI WITH JISP16." International Journal of Modern Physics E 22, no. 07 (July 2013): 1330016. http://dx.doi.org/10.1142/s0218301313300166.

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We review energies and magnetic moments of p-shell nuclei obtained with the ab initio No-Core Full Configuration (NCFC) approach using the JISP16 realistic nucleon–nucleon interaction. We present calculated ground state energies for all stable p-shell nuclei and selected unstable isotopes, as well as their magnetic moments. We also review excitation energies for narrow resonances of A = 6 to 9 nuclei. We compare our results with experimental data and with other ab initio calculations, where available. We illustrate how the decomposition of total angular momentum into intrinsic spin and orbital components provides insights into the structure of states and relationships among states. We illustrate the challenges of obtaining converged results for radii, quadrupole moments and B(E2) values.

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21

Furman, G. B., S. D. Goren, V. M. Meerovich, and V. L. Sokolovsky. "Fictitious spin-12 operators and correlations in quadrupole nuclear spin system." International Journal of Quantum Information 16, no. 01 (February 2018): 1850008. http://dx.doi.org/10.1142/s0219749918500089.

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The Hamiltonian and the spin operators for a spin 3/2 are represented in the basis formed by the Kronecker productions of the [Formula: see text] Pauli matrices. This reformulation allows us to represent a spin 3/2 as a system of two coupled fictitious spins 1/2. Correlations between these fictitious spins are studied using well-developed methods. We investigate the temperature and field dependences of correlations, such as mutual information, classical correlations, entanglement, and geometric and quantum discords in the fictitious spin-1/2 system describing a nuclear spin 3/2 which is placed in magnetic and inhomogeneous electric fields. It is shown that the correlations between the fictitious spins demonstrate properties which differ from those of real two-spin systems. In contrast to real systems all the correlations between the fictitious spins do not vanish with increasing external magnetic field; at a high magnetic field the correlations tend to their limiting values. Classical correlations, quantum and geometric discords reveal a pronounced asymmetry relative to the measurements on subsystems (fictitious spins) even in a uniform magnetic field and at symmetrical EFG, [Formula: see text]. The correlations depend also on the distribution of external charges, on the parameter of symmetry [Formula: see text]. At [Formula: see text] quantum and geometric discords have finite values in a zero magnetic field. The proposed approach may be useful in analysis of properties of particles with larger angular momentum, can provide the way to discover new physical phenomenon of quantum correlations, and can be a useful tool for similar definitions of other physical quantities of complex systems.

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22

WANG, FAN. "NUCLEON SPIN AND ITS GAUGE INVARIANCE AND CANONICAL COMMUTATION RELATION." International Journal of Modern Physics A 20, no. 08n09 (April 10, 2005): 1741–46. http://dx.doi.org/10.1142/s0217751x05023268.

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The nucleon spin structure has been shown to be described by a dynamical constituent quark model with ~85% q3 and [Formula: see text] Fock components. As a QCD system there is no gauge invariance and canonical commutation relation simultaneously satisfied decomposition of the nucleon spin operator. To keep gauge invariance but give up the canonical commutation relation of the angular momentum operator will ruin the multiple moments expansion and the partial wave decomposition. A weak gauge invariant condition is proposed where the canonical commutation relation of angular momentum operator is intact and the gauge invariance is only true for special sets of matrix elements instead of the operators.

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23

LIU, JUEPING. "REPRODUCTION OF THE NUCLEON SPIN EXPERIMENTAL DATA FROM THE IMPROVED ELLIS-JAFFE SUM RULES." Modern Physics Letters A 10, no. 23 (July 30, 1995): 1667–76. http://dx.doi.org/10.1142/s0217732395001782.

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The proton, neutron and deuteron spin experimental data obtained so far are reproduced by using the improved Ellis-Jaffe sum rules, the spin structure of nucleon is then analyzed by assuming that the orbit angular momentum of the partons inside the nucleon is vanishing at a not very large energy scale.

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24

DIEHL, MARKUS. "SPIN AND OTHER ASPECTS OF GENERALIZED PARTON DISTRIBUTIONS." International Journal of Modern Physics A 18, no. 08 (March 30, 2003): 1319–26. http://dx.doi.org/10.1142/s0217751x03014666.

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I discuss how generalized parton distribution probe various aspects of QCD bound states. Topics include the interplay between transverse and longitudinal structure, quantum mechanical interference, orbital angular momentum, helicity flip, and higher-spin targets.

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25

Brodsky, Stanley J., Dae Sung Hwang, Bo-Qiang Ma, and Ivan Schmidt. "Light-cone representation of the spin and orbital angular momentum of relativistic composite systems." Nuclear Physics B 593, no. 1-2 (January 2001): 311–35. http://dx.doi.org/10.1016/s0550-3213(00)00626-x.

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26

Chen, Panying, Xiangdong Ji, Yang Xu, and Yue Zhang. "Angular momentum in non-relativistic QED and photon contribution to spin of hydrogen atom." Physics Letters B 688, no. 1 (April 2010): 55–58. http://dx.doi.org/10.1016/j.physletb.2010.03.045.

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27

Kun, S. Yu, R. Gentner, and L. Lassen. "Spin correlation function of neutrons emitted by a compound nucleus with high angular momentum." Zeitschrift f�r Physik A Hadrons and Nuclei 342, no. 1 (March 1992): 67–70. http://dx.doi.org/10.1007/bf01294490.

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28

ANCHORDOQUI, LUIS A. "WORMHOLES IN SPACE–TIME WITH TORSION." Modern Physics Letters A 13, no. 14 (May 10, 1998): 1095–100. http://dx.doi.org/10.1142/s0217732398001169.

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Analytical wormholes solutions in U 4 theory are presented. It is discussed whether the extremely short range repulsive forces, related to the spin angular momentum of matter, could be the "carrier" of the exoticity that threads the wormhole throat.

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29

Becattini, Francesco, and Michael A. Lisa. "Polarization and Vorticity in the Quark–Gluon Plasma." Annual Review of Nuclear and Particle Science 70, no. 1 (October 19, 2020): 395–423. http://dx.doi.org/10.1146/annurev-nucl-021920-095245.

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The quark–gluon plasma (QGP) produced by collisions between ultrarelativistic heavy nuclei is well described in the language of hydrodynamics. Noncentral collisions are characterized by very large angular momentum, which in a fluid system manifests as flow vorticity. This rotational structure can lead to a spin polarization of the hadrons that eventually emerge from the plasma, and thus these collisions provide experimental access to flow substructure at unprecedented detail. Recently, the first observations of Λ hyperon polarization along the direction of collisional angular momentum were reported. These measurements are in broad agreement with hydrodynamic and transport-based calculations and reveal that the QGP is the most vortical fluid ever observed. However, there remain important tensions between theory and observation that might be fundamental in nature. In the relatively mature field of heavy-ion physics, the discovery of global hyperon polarization and 3D simulations of the collision have opened an entirely new direction of research. We discuss the current status of this rapidly developing area and directions for future research.

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30

CHANG, DARWIN, and PALASH B. PAL. "NUMBER THEORY AND QUANTUM MECHANICS." Modern Physics Letters A 09, no. 20 (June 28, 1994): 1845–51. http://dx.doi.org/10.1142/s0217732394001702.

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We demonstrate a simple contradiction of naive deterministic theories with quantum mechanics by showing that the spin components cannot have deterministic values for many values of the total spin of a particle. Using a theorem in number theory, we work out the complete set of spin values which display such properties. The fact that the set is infinite should prompt some modifications in the usual statement about achieving the classical limit when the value of angular momentum becomes very large.

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31

Buchmann, Alfons J. "Ernest Henley and the shape of baryons." International Journal of Modern Physics E 27, no. 12 (December 2018): 1840009. http://dx.doi.org/10.1142/s0218301318400098.

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Calculations of pion–baryon couplings, baryon quadrupole and octupole moments, baryon spin and orbital angular momentum done in collaboration with Ernest Henley are reviewed. A common theme of this work is the shape of baryons. Also, a personal account of my work with Ernest Henley during the period 1999–2013 is given.

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32

Zhu, Wei, and Jianhong Ruan. "Nucleon spin structure." International Journal of Modern Physics E 24, no. 10 (October 2015): 1550077. http://dx.doi.org/10.1142/s0218301315500779.

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This paper contains three parts relating to the nucleon spin structure in a simple picture of the nucleon: (i) The polarized gluon distribution in the proton is dynamically predicted starting from a low scale by using a nonlinear quantum chromodynamics (QCD) evolution equation — the Dokshitzer–Gribov–Lipatov–Altarelli–Paris (DGLAP) equation with the parton recombination corrections, where the nucleon is almost consisted only of valence quarks. We find that the contribution of the gluon polarization to the nucleon spin structure is much larger than the predictions of most other theories. This result suggests that a significant orbital angular momentum of the gluons is required to balance the gluon spin momentum. (ii) The spin structure function [Formula: see text] of the proton is studied, where the perturbative evolution of parton distributions and nonperturbative vector meson dominance (VMD) model are used. We predict [Formula: see text] asymptotic behavior at small x from lower Q2to higher Q2. The results are compatible with the data including the early HERA estimations and COMPASS new results. (iii) The generalized Gerasimov–Drell–Hearn (GDH) sum rule is understood based on the polarized parton distributions of the proton with the higher twist contributions. A simple parameterized formula is proposed to clearly present the contributions of different components in the proton to [Formula: see text]. The results suggest a possible extended objects with size 0.2–0.3 fm inside the proton.

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DERIGLAZOV, A. A. "NONRELATIVISTIC SPIN: à la BEREZIN–MARINOV QUANTIZATION ON A SPHERE." Modern Physics Letters A 25, no. 32 (October 20, 2010): 2769–77. http://dx.doi.org/10.1142/s0217732310033980.

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Reparametrization invariant dynamics on a sphere, being parametrized by angular momentum coordinates, represents an appropriate framework for semiclassical description of nonrelativistic spin. The space can be quantized according to Berezin–Marinov prescription, replacing the coordinates by Pauli matrices. Following the scheme, we present two semiclassical models for describing spin without the use of Grassmann variables. The first model implies Pauli equation upon the canonical quantization. The second model produces nonrelativistic limit of the Dirac equation implying correct value for the electron spin magnetic moment.

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34

SUZUKI, HISAO, and EIICHI TAKASUGI. "ABSORPTION PROBABILITY OF DE SITTER HORIZON FOR MASSLESS FIELDS WITH SPIN." Modern Physics Letters A 11, no. 06 (February 28, 1996): 431–36. http://dx.doi.org/10.1142/s0217732396000473.

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The thermal flux emitted by a de Sitter universe due to interaction with massless fields with spin is examined. We found the exact solutions of the radial equation for spin 0, 1/2, 1 and 2 and calculated the absorption probability using asymptotic expansion for high frequency limit. It turns out that the absorption coefficients are universal for all bosonic fields, i.e. they do not depend on the spin, but depend only on the total angular momentum. In particular, for spin-1/2 fermions, we found nonvanishing absorption probability in contrast to the previous vanishing result.

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35

DAHIYA, HARLEEN, and MANMOHAN GUPTA. "CHIRAL QUARK MODEL (χQM) AND THE NUCLEON SPIN." International Journal of Modern Physics A 19, no. 29 (November 20, 2004): 5027–41. http://dx.doi.org/10.1142/s0217751x04019949.

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Using χ QM with configuration mixing, the contribution of the gluon polarization to the flavor singlet component of the total spin has been calculated phenomenologically through the relation [Formula: see text] as defined in the Adler–Bardeen scheme, where ΔΣ on the right-hand side is Q2 independent. For evaluation the contribution of gluon polarization [Formula: see text], ΔΣ is found in the χ QM by fixing the latest E866 data pertaining to [Formula: see text] asymmetry and the spin polarization functions whereas ΔΣ(Q2) is taken to be 0.30±0.06 and αs=0.287±0.020, both at Q2=5 GeV 2. The contribution of gluon polarization Δg' comes out to be 0.33 which leads to an almost perfect fit for spin distribution functions in the χ QM . When its implications for magnetic moments are investigated, we find perfect fit for many of the magnetic moments. If an attempt is made to explain the angular momentum sum rule for proton by using the above value of Δg', one finds the contribution of gluon angular momentum to be as important as that of the [Formula: see text] pairs.

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36

Tamagno, P., and O. Litaize. "Impact of nuclear inertia momenta on fission observables." EPJ Web of Conferences 193 (2018): 01004. http://dx.doi.org/10.1051/epjconf/201819301004.

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Fission is probably the nuclear process the less accurately described with current models because it involves dynamics of nuclear matter with strongly coupled manybody interactions. It is thus diffcult to find models that are strongly rooted in good physics, accurate enough to reproduce target observables and that can describe many of the nuclear fission observables in a consistent way. One of the most comprehensive current modeling of the fission process relies on the fission sampling and Monte-Carlo de-excitation of the fission fragments. This model is implemented for instance in the FIFRELIN code. In this model fission fragments and their state are first sampled from pre-neutron fission yields, angular momentum distribution and excitation energy repartition law then the decay of both initial fragments is simulated. This modeling provides many observables: prompt neutron and gamma fission spectra, multiplicities and also fine decompositions: number of neutrons emitted as a function of the fragment mass, spectra per fragments, etc. This model relies on nuclear structure databases and on several basic nuclear models describing for instance gamma strength functions or level densities. Additionally some free parameters are still to be determined, namely two parameters describing the excitation energy repartition law, the spin cutoff of the heavy and light fragments and a rescaling parameter for the rotational inertia momentum of the fragments with respect of the rigid-body model. In the present work we investigate the impact of this latter parameter. For this we mainly substitute the corrected rigid-body value by a quantity obtained from a microscopic description of the fission fragment. The independent-particle model recently implemented in the CONRAD code is used to provide nucleonic wave functions that are required to compute inertia momenta with an Inglis-Belyaev cranking model. The impact of this substitution is analyzed on different fission observables provided by the FIFRELIN code.

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37

Thomas, A. W., H. H. Matevosyan, and A. Casey. "Comment on “The role of the orbital angular momentum in the proton spin” by M. Wakamatsu." European Physical Journal A 46, no. 2 (September 25, 2010): 325–26. http://dx.doi.org/10.1140/epja/i2010-11035-8.

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KHORRAMIAN, ALI N., A. MIRJALILI, and S. ATASHBAR TEHRANI. "QUARK DISTRIBUTIONS AND NUCLEON SPIN STRUCTURE." International Journal of Modern Physics A 20, no. 08n09 (April 10, 2005): 1923–26. http://dx.doi.org/10.1142/s0217751x05023645.

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In this paper we calculate spin dependence of parton distributions and proton structure function. The polarized valon distributions in a proton and the polarized parton distributions inside the valon are necessary to obtain the polarized parton distributions in a proton. The results of our calculations for the proton structure function, [Formula: see text] are in good agreement with the available experimental data. We obtain the spin contribution and angular momentum of the valons to the proton.

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Wakamatsu, Masashi. "Is gauge-invariant complete decomposition of the nucleon spin possible?" International Journal of Modern Physics A 29, no. 09 (April 8, 2014): 1430012. http://dx.doi.org/10.1142/s0217751x14300129.

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Is gauge-invariant complete decomposition of the nucleon spin possible? Although it is a difficult theoretical question which has not reached a complete consensus yet, a general agreement now is that there are at least two physically inequivalent gauge-invariant decompositions (I) and (II) of the nucleon. In these two decompositions, the intrinsic spin parts of quarks and gluons are just common. What discriminate these two decompositions are the orbital angular momentum parts. The orbital angular momenta of quarks and gluons appearing in the decomposition (I) are the so-called "mechanical" orbital angular momenta, while those appearing in the decomposition (II) are the generalized (gauge-invariant) "canonical" ones. By this reason, these decompositions are also called the "mechanical" and "canonical" decompositions of the nucleon spin, respectively. A crucially important question is which decomposition is more favorable from the observational viewpoint. The main objective of this concise review is to try to answer this question with careful consideration of recent intensive researches on this problem.

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RODRÍGUEZ-GUZMÁN, R. R., J. L. EGIDO, and L. M. ROBLEDO. "DESCRIPTION OF THE SUPERDEFORMED BAND OF 36Ar WITH THE GOGNY FORCE." International Journal of Modern Physics E 13, no. 01 (February 2004): 139–46. http://dx.doi.org/10.1142/s0218301304001862.

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The superdeformed band of 36 Ar is studied with the Gogny force D1S and the angular momentum projected generator coordinate method for the quadrupole moment. The band head excitation energy, moments of inertia, B(E2) transition probabilities and stability against quadrupole fluctuations at low spin are studied. The Self Consistent Cranking method is also used to describe the superdeformed rotational band. In addition, properties of some normal deformed states are discussed.

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Chakraborty, B., and T. R. Govindarajan. "Hamiltonian Formulation of Quantum Hall Skyrmions with Hopf Term." Modern Physics Letters A 12, no. 09 (March 21, 1997): 619–30. http://dx.doi.org/10.1142/s0217732397000649.

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We study the nonrelativistic nonlinear sigma model with Hopf term in this letter. This is an important issue because of its relation to the currently interesting studies in skyrmions in quantum Hall systems. We perform the Hamiltonian analysis of this system in CP1 variables. When the coefficient of the Hopf term becomes zero we get the Landau–Lifshitz description of the ferromagnets. The addition of Hopf term dramatically alters the Hamiltonian analysis. The spin algebra is modified giving a new structure and interpretation to the system. We point out momentum and angular momentum generators and new features they bring into the system.

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ZOLLER, V. R. "PROTON HELICITY FLOW TO MESONIC CLOUD AND AXIAL COUPLINGS OF BARYONS." Modern Physics Letters A 08, no. 12 (April 20, 1993): 1113–23. http://dx.doi.org/10.1142/s0217732393002592.

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We apply the relativistic light-cone perturbation theory to a flow of the helicity of baryons to the angular momentum of the mesonic cloud. Starting with the SU(6) symmetry, we find good description of the axial couplings in β-decay of hyperons. In the light-cone technique, the pattern of the spin-flip of nucleons differs significantly from that expected in the conventional non-relativistic models.

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OHTA, KAZUTOSHI, and HISAO SUZUKI. "DIRAC OPERATORS ON QUANTUM-TWO SPHERES." Modern Physics Letters A 09, no. 25 (August 20, 1994): 2325–33. http://dx.doi.org/10.1142/s0217732394002197.

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We investigate the spin-1/2 fermions on quantum-two spheres. It is shown that the wave functions of fermions and a Dirac operator on quantum-two spheres can be constructed in a manifestly covariant way under the quantum group SU (2)q. The concept of total angular momentum and chirality can be expressed by using q-analog of Pauli-matrices and appropriate commutation relations.

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LARSEN, A. L. "LOGARITHMIC CORRECTION TO SCALING FOR MULTISPIN STRINGS IN THE AdS5 BLACK HOLE BACKGROUND." International Journal of Modern Physics A 23, no. 05 (February 20, 2008): 719–27. http://dx.doi.org/10.1142/s0217751x08038482.

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We find new explicit solutions describing closed strings spinning with equal angular momentum in two independent planes in the AdS5 black hole space–time. These are 2n-folded strings in the radial direction and also winding m times around an angular direction. We specially consider these solutions in the long string and high temperature limit, where it is shown that there is a logarithmic correction to the scaling between energy and spin. This is similar to the one-spin case. The strings are spinning, or actually orbiting around the black hole of the AdS5 black hole space–time, similar to the solutions previously found in black hole space–times.

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THOMAS, ANTHONY W., ANDREW CASEY, and HRAYR H. MATEVOSYAN. "WHAT WE KNOW AND DON'T KNOW ABOUT THE ORIGIN OF THE SPIN OF THE PROTON." International Journal of Modern Physics A 25, no. 22 (September 10, 2010): 4149–62. http://dx.doi.org/10.1142/s0217751x10050470.

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The origin of the spin of the proton is one of the most fundamental questions in modern hadron physics. Although tremendous progress has been made since the discovery of the "spin crisis" brought the issue to the fore, much remains to be understood. We carefully review what is known and, especially in the case of lattice QCD, what is not known. We also explain the importance of QCD inspired models in providing a physical picture of proton structure and the connection between those models and what is measured experimentally and on the lattice. We specifically apply these ideas to the issue of quark orbital angular momentum in the proton. We show that the Myhrer–Thomas resolution of the proton spin crisis is remarkably consistent with modern information from lattice QCD.

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MACKENZIE, R., and FRANK WILCZEK. "PECULIAR SPIN AND STATISTICS IN TWO SPACE DIMENSIONS." International Journal of Modern Physics A 03, no. 12 (December 1988): 2827–53. http://dx.doi.org/10.1142/s0217751x88001181.

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This is an elementary, self-contained review of some peculiarities of quantum mechanics for 2+1 dimensional systems that are at least instructive and perhaps important. In particular, we argue that angular momentum need not be quantized and that statistics interpolating between Fermi and Bose statistics can be constructed. There are possible direct applications to collective excitations in solids and to cosmic strings, and an important moral lesson regarding the “wave function of the universe.”

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Liendo, J. A., E. Castro, R. Gómez, and D. D. Caussyn. "A study of shell model neutron states in 207,209Pb using the generalized Woods–Saxon plus spin-orbit potential." International Journal of Modern Physics E 25, no. 08 (August 2016): 1650055. http://dx.doi.org/10.1142/s0218301316500555.

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The experimental binding energies of single-particle and single-hole neutron states belonging to neutron shells that extend from [Formula: see text] = 126–184 and 82–126, respectively, have been reproduced by solving the Schrödinger equation with a potential that has two components: the generalized Woods–Saxon (GWS) potential and the spin-orbit (SO) coupling term. The GWS potential contains the traditional WS potential plus a term (SU) whose intensity reaches a maximum in the nuclear surface. Our results indicate the existence of an explicit relationship between the strength of the SU potential and the orbital angular momentum quantum number [Formula: see text] of the state. This dependence has been used to make reasonable predictions for the excitation energy centroids of states located inside and outside the neutron shells investigated. Comparisons are made with results reported in previous investigations.

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YAHIKOZAWA, SHIGEAKI. "A MODEL OF MEMBRANE WITH FRACTIONAL SPIN AND UNUSUAL STATISTICS." International Journal of Modern Physics A 06, no. 06 (March 10, 1991): 935–54. http://dx.doi.org/10.1142/s0217751x91000514.

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We present a model of membrane with fractional world-volume spin and exotic statistics. The model is constructed by coupling the bosonic membrane to the world-volume U(1) Chern-Simons term. Dirac’s method for the constrained system is used to quantize this theory and to show that the membrane has exotic statistics. We also evaluate finite size effects and clarify the relationship between a conserved charge in space-time and an angular-momentum operator on a world-volume.

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GARCIA DE ANDRADE, L. C. "DISTRIBUTIONAL TORSION OF COSMIC STRINGS WITH POLARIZED SPINNING MATTER." Modern Physics Letters A 13, no. 27 (September 7, 1998): 2227–30. http://dx.doi.org/10.1142/s0217732398002370.

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A cosmic string of finite size in Weitzenböck space–time is built where spin polarized particles can be found along the string and orthogonal to it. Only spinning particles polarized along the string contribute to the angular momentum of the string while the other is only a torsion source like in Einstein–Cartan (EC) theory. Cartan torsion is given by a δ-Dirac distribution and the metric is the lift of (2+1)-gravity point particles to (3+1)-cosmic strings.

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JATKAR, DILEEP P., and SUMATHI RAO. "ANYONS AND GAUSSIAN CONFORMAL FIELD THEORIES." Modern Physics Letters A 06, no. 04 (February 10, 1991): 289–94. http://dx.doi.org/10.1142/s0217732391000257.

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We identify the spin of the anyons with the holomorphic dimension of the primary fields of a Gaussian conformal field theory. The angular momentum addition rules for anyons go over to the fusion rules for the primary fields and the r↔1/2r duality of the Gaussian CFT is reproduced by a charge-flux duality of the anyons. For a U(1) Chern-Simons theory with topological mass parameter k=2n, N-anyon states on the torus have 2n components, which correspond to the 2n conformal blocks of an N-point function in the Gaussian conformal field theory.

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