Re-engineering the electron: A composite model

In order to simultaneously maintain the ship magnetic field modeling accuracy, reduce the number of coefficient matrix conditions and the model computational complexity, an improved composite model is designed by introducing the magnetic dipole array model with a single-axis magnetic moment on the basis of the hybrid ellipsoid and magnetic dipole array model. First, the improved composite model of the ship's magnetic field is established based on the magnetic dipole array model with 3-axis magnetic moment, the magnetic dipole array model with only x-axis magnetic moment, and the ellipsoid model. Secondly, the set of equations for calculating the magnetic moments of the composite model is established, and for the problem of solving the pathological set of equations, the least-squares estimation, stepwise regression method, Tikhonov, and truncated singular value decomposition regularization methods are introduced in terms of the magnetic field, and generalized cross-validation is used to solve the optimal regularization parameters. Finally, a ship model test is designed to compare and analyze the effectiveness of the composite and hybrid models in four aspects: the number of coefficient matrix conditions of the model equation set, the relative error of magnetic field fitting, the relative error of magnetic field extrapolation, and the computational time complexity. The modeling results based on the ship model test data show that the composite model can be used for modeling the magnetic field of ships, and compared with the hybrid model, it reduces the number of coefficient matrix conditions and improves the computational efficiency on the basis of retaining a higher modeling accuracy, and it can be effectively applied in related scientific research and engineering.

The energy dependence of neutron-deuteron elastic scattering observables has been calculated from 5 to 45 MeV via rigorous three-nucleon calculations using the Bonn B nucleon-nucleon interaction. The goal of these calculations was to identify energy and angular regions that may be investigated experimentally to study the question of charge-symmetry breaking in the3PJ nucleon-nucleon forces and/or Coulomb interactions. It was found that the measurement of the neutron-deuteron elastic analyzing power at 16 and 22.7 MeV and its comparison to proton-deuteron data obtained at the same incident energy is the most promising case for studying the issue of charge-symmetry breaking in the3PJ nucleon-nucleon forces and/or Coulomb interactions.

Analyzing trade-off issues in synthesis of magnetic polymer compounds through theoretical investigation

The electronic spectrum of a trimer with a variable number of electrons has been calculated in the Hubbard model by exact diagonalization. The dependences of the chemical potential shift, magnetic moment, and energy level splitting near the chemical potential on the magnetic field, Coulomb interaction between the electrons located at the vertices of the triangle, trimer deformation, and three-center interaction have been established. The removal of magnetic degeneracy in the trimer when the intersite Coulomb and three-center interactions are taken into account and the formation of a singlet pair of electrons under trimer deformation have been detected.

Spin effects are generally thought to be inessential complications in particle physics. The discovery of large spin-dependent terms in recent pp and np experiments with polarized particles, which have been discussed extensively in the previous Proceedings of this conference,1 shows that this is not the case. I shall show that spin effects not only play a major role in scattering at high energies, but also dominate the bound-state problems at short distances. Consequently any model or theory of hadrons, or any subconstituent model using spin-1/2-components (with magnetic moments) must take into account the following purely electromagnetic effect: The (electro)magnetic interactions become very strong at short distances and give rise to the formation of massive, narrow resonances between light spin-1/2— particles which subsequently decay very weakly by tunnelling. In the following we explain this phenomenon and extend it to the case of the neutrino, assumed to have a small anomalous magnetic moment.

In the large-scale world we commonly associate magnetic fields with electrical currents. Our experience in the large-scale world is of little value, however, in providing a theoretical description of the origin of the magnetism of remanence-carrying materials. Although we can use our experience of classical physics to equate an orbiting electron to a current loop and determine the resultant magnetic dipole moment, this turns out to be of little help, as the observed magnetism of solids is due almost exclusively to the magnetic dipole moment associated with the ‘spin’ of the electron. The spin of the electron has no analogue in classical physics and is a feature of the quantum mechanical description of the inhabitants of the submicroscopic world of atoms and electrons. The electron has angular momentum quantized in units of h/2π (= ћ) where h,Planck’s constant, equals 6.63 × 10−34 joule s, and a spin quantum number s = 1/2. The component of spin angular momentum in a specified direction is sћ and the associated magnetic moment (elm)sћ where e and m are the electronic charge and mass. The electron can therefore be regarded simply as a microscopic magnet with magnetic moment (eћ)/(2m),this being the fundamental unit of magnetic moment, the Bohr magneton, s(= 9.27 × 10−24A m2).

We propose an economical model to explain the apparent 130 GeV gamma ray peak, found in the Fermi/LAT data, in terms of dark matter (DM) annihilation through a dipole moment interaction. The annihilating dark matter particles represent a subdominant component, with mass density 7--17% of the total DM density; and they only annihilate into $\ensuremath{\gamma}\ensuremath{\gamma}$, $\ensuremath{\gamma}Z$, and $ZZ$, through a magnetic (or electric) dipole moment. Annihilation into other standard model particles is suppressed, due to a DM mass splitting in the magnetic dipole case, or to $p$-wave scattering in the electric dipole case. In either case, the observed signal requires a dipole moment of strength $\ensuremath{\mu}\ensuremath{\sim}2/\mathrm{TeV}$. We argue that composite models are the preferred means of generating such a large dipole moment, and that the magnetic case is more natural than the electric one. We present a simple model involving a scalar and fermionic techniquark of a confining SU(2) gauge symmetry. We point out some generic challenges for getting such a model to work. The new physics leading to a sufficiently large dipole moment is below the TeV scale, indicating that the magnetic moment is not a valid effective operator for LHC physics, and that production of the strongly interacting constituents, followed by techni-hadronization, is a more likely signature than monophoton events. In particular, four-photon events from the decays of bound state pairs are predicted.

This calculation focuses on the effect of the Coulomb interaction U and the volume compression (VC) on both spin (m(s)) and orbital (m(o)) magnetic moment of NiO by using the local spin density approximation plus the Coulomb interaction (LSDA + U) method within full potential linear muffin-tin orbital (FP-LMTO). Our calculated results indicated that both spin and orbital magnetic moment strongly correlated to U and VC. The relevant results exhibited the increasing spin and orbital magnetic moments with increasing Coulomb interaction and decreasing volume compression. The interesting behavior appears when volume compression is greater than 70% at which m(s) collapses whereas m(o) linearly decreases. Further increase of volume compression to be at 80% leads to the disappearance of both magnetic moments. The present results exhibit the good correspondence to the experimental data at the normal pressure and U value of 6 eV.

The electronic Hamiltonian for a general atom is obtained as far as terms in 1/c2 and m/MA by reducing a relativistic wave equation with four components for each electron and nucleon to an approximately relativistic form with two components per particle. The presence of non-Hermitian terms in the reduced Hamiltonian is explained. Relativistic corrections to the Coulomb and nuclear interactions and the effect of the intrinsic magnetic moments are treated by first-order perturbation theory. The electronic Hamiltonian is obtained in the centre-of-mass system of the atom. The hyperfine structure interaction is obtained by expressing all electron-nucleon terms as multipole expansions, giving the previously known hyperfine structure expansion with recoil corrections. The exact operator for the nuclear field effect in isotope shift is obtained from the Coulomb interaction. The presence of other corrections depending on nuclear structure is indicated. Terms referring only to s electrons are not considered as the reduction procedure used does not cover the contact approach of particles (cf. Ma 1956). The usual calculation of the normal mass effect in isotope shift is investigated for non-s-electron configurations and is shown to be justified if 0.1% of the spin-orbit interaction and the whole of the other relativistic perturbations are negligible in comparison with the term value.

There is no doubt [1-3] that neutrino electromagnetic properties open a window to new physics. The most general form [1] of a neutrino electromagnetic vertex function $\Lambda_{\mu}^{ij}(q) = \left( \gamma_{\mu} - q_{\mu} {q}/q^{2} \right) \left[ f_{Q}^{ij}(q^{2}) + f_{A}^{ij}(q^{2}) q^{2} \gamma_{5} \right] \nonumber - i \sigma_{\mu\nu} q^{\nu} \left[ f_{M}^{ij}(q^{2}) + i f_{E}^{ij}(q^{2}) \gamma_{5} \right]$ , where $\Lambda_{\mu}(q)$ and form factors $f_{Q,A,M,E}(q^2)$ are $3\times 3$ matrices in the space of massive neutrinos, in the case of coupling with a real photon ($q^2=0$) provides four sets of neutrino electromagnetic characteristics: 1) the dipole magnetic moments $\mu_{ij}=f_{M}^{ij}(0)$, 2) the dipole electric moments $\epsilon_{ij}=f_{E}^{ij}(0)$, 3) the millicharges $q_{ij}=f_{Q}^{ij}(0)$ and 4) the anapole moments $a_{ij}=f_{A}^{ij}(0)$. So far, there are no indications in favour of nonzero electromagnetic properties of neutrinos from either data from laboratory experiments with neutrino fluxes from ground-based sources or from astrophysics observations. However, the study of the electromagnetic properties of neutrinos attracts considerable attention. The most well understood and studied are the dipole magnetic and electric moments. In a minimal extension of the Standard Model the diagonal magnetic moment of a Dirac neutrino is given [4] by $\mu^{D}_{ii} = \frac{3e G_F m_{i}}{8\sqrt {2} \pi ^2}\approx 3.2\times 10^{-19} \Big(\frac{m_i}{1 \mathrm{eV} }\Big) \mu_{B}$ ($\mu_B$ is the Bohr magneton). Majorana neutrinos can have only transition (off-diagonal) magnetic moments $\mu^{M}_{i\neq j}$. The most stringent constraints on the effective neutrino magnetic moment are obtained with the reactor antineutrinos: $\mu_{\nu} < 2.9 \times 10^{-11} \mu_{B}$ (GEMMA Collaboration [5]), and solar neutrinos: ${\mu}_{\nu_e}\leq 2.8 \times 10^{-11} \mu _B$ (Borexino Collaboration [6]). An astrophysical bound (for both Dirac and Majorana neutrinos) is provided [7-9] by observations of the properties of globular cluster stars: $\Big( \sum _{i,j}\left| \mu_{ij}\right| ^2\Big) ^{1/2}\leq (2.2{-}2.6) \times 10^{-12} \mu _B$. A general and termed model-independent upper bound on the Dirac neutrino magnetic moment, that can be generated by an effective theory beyond a minimal extension of the Standard Model, has been derived in [10]: $\mu_{\nu}\leq 10^{-14}\mu_B$. The corresponding limit for transition moments of Majorana neutrinos is much weaker [11]. In the theoretical framework with $CP$ violation a neutrino can have nonzero electric moments $\epsilon_{ij}$. In the laboratory neutrino scattering experiments for searching $\mu_{\nu}$ (for instance, in the GEMMA experiment) the electric moment $\epsilon_{ij}$ contributions interfere with those due to $\mu_{ij}$. Thus, these kind of experiments also provide constraints on $\epsilon_{ij}$. The astrophysical bounds on $\mu_{ij}$ are also applicable for constraining $\epsilon_{ij}$ (see [7-9] and [12]). In what follows below we give a fast flash on less know neutrino electromagnetic characteristics, namely on the neutrino millicharge, charge radius and anapole moment and give some comments on the future prospects of neutrino electromagnetic properties.

&lt;sec&gt;Two-dimensional materials have shown excellent optical, mechanical, thermal or magnetic properties, and have promising applications in the high performance electronic, optical, spintronic devices and energy transfer, energy storage, etc. Monolayer transition metal silicide CrSi&lt;sub&gt;2&lt;/sub&gt; has shown ferromagnetism and metal properties in previous studies, and it is expected to become a new two-dimensional material. The Ti, V, Co, Ni doped two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; are studied with different doping concentrations by using the first-principal pseudopotential plane wave method based on density functional theory, and electronic structure, magnetic and optical properties are calculated and analyzed. The results show that the density of states in the two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; system is asymmetric, and the crystal cells have obvious ferromagnetism with a magnetic moment of 3.55 &lt;i&gt;μ&lt;/i&gt;B. Two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; has strong absorptivity and reflectivity in the far infrared and ultraviolet range, showing excellent optical properties.&lt;/sec&gt;&lt;sec&gt;The electronic structures and magnetic properties of Ti, V, Co or Ni doped CrSi&lt;sub&gt;2&lt;/sub&gt; with different concentrations are calculated and analyzed, and the results show that the magnetic moment of the two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; varies after doping different elements at a doping concentration of 3.70 at%. After doping Ti, the magnetic moment of the system changes to 0 &lt;i&gt;μ&lt;/i&gt;B at a doping concentration of 3.70 at%, showing that it is an indirect semiconductor. After doping V, the magnetic moment becomes smaller at a doping concentration of 3.70 at%, and the system has two degrees of freedom: electron charge and spin, showing the properties of diluted magnetic semiconductors. After doping Ni, the band gap &lt;i&gt;E&lt;/i&gt;&lt;sub&gt;g&lt;/sub&gt;=0.09 eV appears in the spin-up band of the system at a doping concentration of 3.70 at%, while the spin-down band is metallic, and the system shows semi-metallic properties. The magnetic moment changes to 3.71 &lt;i&gt;μ&lt;/i&gt;B after doping Ti at a doping concentration of 7.41 at%. After doping Co and Ni, the magnetic moment of the system becomes smaller at the doping concentration of 7.41 at%, and the spin-down 3&lt;i&gt;d&lt;/i&gt; orbital electrons of ferromagnetic elements take the dominant position. After doping Ni, the magnetic moment becomes 0.37 &lt;i&gt;μ&lt;/i&gt;B at the doping concentration of 7.41 at%. After doping Ti, the magnetic moment becomes 2.79 &lt;i&gt;μ&lt;/i&gt;B at a doping concentration of 33.3 at at%, after doping V, the magnetic moment becomes 2.27 &lt;i&gt;μ&lt;/i&gt;B, and the degree of spin becomes weaker at a doping concentration of 11.1 at%. After doping Co, the magnetic moment becomes 1.81 &lt;i&gt;μ&lt;/i&gt;B at the doping concentration of 11.1 at%. The magnetic moment becomes 1.5 &lt;i&gt;μ&lt;/i&gt;B after doping Ni at the doping concentration of 11.1 at%, which proves that the spin-up &lt;i&gt;d&lt;/i&gt; orbital has less electronic contribution to the magnetic moment. The energy band range of each system is enlarged, and the interaction between atoms is enlarged, and the energy level splitting energy is enlarged at the doping concentration of 11.1 at%, which indicates that the effective mass of the system becomes smaller, the mobility of carriers turns stronger, and the metallization of materials grows stronger.&lt;/sec&gt;&lt;sec&gt;The optical properties of Ti, V, Co or Ni doped CrSi&lt;sub&gt;2&lt;/sub&gt; with different concentrations are calculated and analyzed, and the results show that the two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; after being doped has good optical properties. For most of systems, their optical properties are improved and blue-shifted at the doping concentrations of 3.70 at% and 7.41 at%, but the absorption peak is red-shifted at the doping concentration of 11.1 at%. By studying the properties of doped two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt;, it is found that the two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; has excellent electronic structure and optical properties, and the electronic structure, magnetic and optical properties of the two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; can be effectively changed by doping. Two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; is expected to be a promising material for preparing new high reliability and high stability spintronic devices, and the present research provides an effective theoretical basis for developing the two-dimensional CrSi&lt;sub&gt;2&lt;/sub&gt; based devices.&lt;/sec&gt;

International Journal of Modern Physics AVol. 05, No. 21, pp. 4021-4198 (1990) No AccessPRODUCTION, STRUCTURE AND DECAY OF HYPERNUCLEIH. BANDŌ, T. MOTOBA, and J. ŽOFKAH. BANDŌDivision of Mathematical Physics, Fukui University, Fukui 910, Japan Institute for Nuclear Study, University of Tokyo, Tanashi, Tokyo 188, JapanDeceased on January 6, 1990, in Kyoto., T. MOTOBALaboratory of Physics, Osaka Electro-Communication University, Neyagawa, Osaka 572, Japan, and J. ŽOFKANuclear Physics Institute, Czechoslovak Academy of Sciences, 25068 Řež, Czechoslovakiahttps://doi.org/10.1142/S0217751X90001732Cited by:236 AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail You currently do not have access to the full text article. Recommend the journal to your library today! FiguresReferencesRelatedDetailsCited By 236Experimental Aspect of S = –2 HypernucleiKazuma Nakazawa25 November 2022Extended optimal Fermi averaging for near-recoilless Λ production in the ( K−, π− ) reaction on nucleiToru Harada and Yoshiharu Hirabayashi15 June 2022 | Physical Review C, Vol. 105, No. 6Hyperon dynamics and production of multi-strangeness hypernuclei in heavy-ion collisions at 3A GeVHui-Gan Cheng and Zhao-Qing Feng1 Jan 2022 | Physics Letters B, Vol. 824Hypernuclei formation in spallation reactions by coupling the Liège intranuclear cascade model to the deexcitation code ABLAJ. L. Rodríguez-Sánchez, J. Cugnon, J.-C. David, J. Hirtz and A. Kelić-Heil et al.24 January 2022 | Physical Review C, Vol. 105, No. 1Selected highlights of the production of light (anti-)(hyper-)nuclei in ultra-relativistic heavy-ion collisionsBenjamin Dönigus4 November 2020 | The European Physical Journal A, Vol. 56, No. 11Medium effects on Ξ− production in the nuclear ( K−,K+ ) reactionToru Harada and Yoshiharu Hirabayashi17 August 2020 | Physical Review C, Vol. 102, No. 2Evaluation of hypernuclei in relativistic ion collisionsN. Buyukcizmeci, A. S. Botvina, R. Ogul and M. Bleicher18 August 2020 | The European Physical Journal A, Vol. 56, No. 8On the survey of nuclei and hypernuclei in multifragmentationN Buyukcizmeci, R Ogul, A S Botvina and M Bleicher5 June 2020 | Physica Scripta, Vol. 95, No. 7Statistical double Λ hypernuclear formation from Ξ− absorption at rest in light nucleiAkira Ohnishi, Chikako Ishizuka, Kohsuke Tsubakihara and Yuichi Hirata18 June 2020 | Progress of Theoretical and Experimental Physics, Vol. 2020, No. 6A study on the ground and excited states of hypernucleiS Pal, R Ghosh, B Chakrabarti and A Bhattacharya14 February 2020 | Physica Scripta, Vol. 95, No. 4Superheavy nuclei and hypernuclei: extending the limits of the nuclear chartChhanda Samanta6 September 2019 | Journal of Radioanalytical and Nuclear Chemistry, Vol. 322, No. 1First investigation of hypernuclei in reactions via analysis of emitted bremsstrahlung photonsXin Liu, Sergei P. Maydanyuk, Peng-Ming Zhang and Ling Liu20 June 2019 | Physical Review C, Vol. 99, No. 6Single-particle spectral function of the Λ hyperon in finite nucleiIsaac Vidaña1 Jan 2019Binding, bonding and charge symmetry breaking in Λ-hypernucleiChhanda Samanta and Thomas A. Schmitt1 Jan 2019Formation of hypernuclei in relativistic ion, hadron and lepton collisionsAlexander Botvina, Marcus Bleicher and Nihal Buyukcizmeci1 Jan 2019Production of $ \Lambda$Λ-hypernuclei and evaluation of their binding energies via the double yield ratioN. Buyukcizmeci, A. S. Botvina, R. Ogul, A. Ergun and M. Bleicher17 January 2019 | The European Physical Journal A, Vol. 55, No. 1Statistical production and binding energy of hypernucleiN. Buyukcizmeci, A. S. Botvina, A. Ergun, R. Ogul and M. Bleicher6 December 2018 | Physical Review C, Vol. 98, No. 6Hypernuclear non-mesonic weak decays in the extended meson exchange modelKazunori Itonaga, Toshio Motoba and Thomas A Rijken24 November 2018 | Progress of Theoretical and Experimental Physics, Vol. 2018, No. 11Relativistic mean-field approach for Λ,Ξ , and Σ hypernucleiZ.-X. Liu, C.-J. Xia, W.-L. Lu, Y.-X. Li and J. N. Hu et al.22 August 2018 | Physical Review C, Vol. 98, No. 2New semi-empirical formulae for the binding and separation energies of single $\Lambda$ Λ hypernucleiK. P. Santhosh and C. Nithya29 August 2018 | The European Physical Journal Plus, Vol. 133, No. 8Theoretical studies on the $$\alpha $$ α decay half-lives of hyper and normal isotopes of PoK P Santhosh and C Nithya10 February 2018 | Pramana, Vol. 90, No. 3Massive neutron stars and Λ-hypernuclei in relativistic mean field modelsTing-Ting Sun, Cheng-Jun Xia, Shi-Sheng Zhang and M. S. Smith8 February 2018 | Chinese Physics C, Vol. 42, No. 2Baryons and baryon resonances in nuclear matterHorst Lenske, Madhumita Dhar, Theodoros Gaitanos and Xu Cao1 Jan 2018 | Progress in Particle and Nuclear Physics, Vol. 98Processes of hypernuclei formation in relativistic ion collisionsAlexander Botvina, Marcus Bleicher, A. Mischke and P. Kuijer2 February 2018 | EPJ Web of Conferences, Vol. 171Production of Hypernuclei by AntiprotonsHorst Lenske, Alexei Larionov and P. Bühler25 June 2018 | EPJ Web of Conferences, Vol. 181Superheavy Nuclei to Hypernuclei: A Tribute to Walter GreinerChhanda Samanta, Y. Aharonov, L. Bravina and S. Kabana3 August 2018 | EPJ Web of Conferences, Vol. 182Enhanced 3α radius in 12C probed by nuclear reactionsM. Ito, M. Nakao, S. Hirao, Y. Funaki and T. Yamada1 Jan 2018Study of ground state binding energies of the single Ξ and Λ hypernuclei by using numerical computationA. Armat and H. Hassanabadi1 Nov 2017 | Canadian Journal of Physics, Vol. 95, No. 11Distillation of scalar exchange by coherent hypernucleus production in antiproton–nucleus collisionsA.B. Larionov and H. Lenske1 Oct 2017 | Physics Letters B, Vol. 773Productions of \(_{\Lambda }^{19}\text{F}\) and Its Electromagnetic PropertiesAtsushi Umeya and Toshio Motoba18 July 2017Production of (Anti-)(Hyper)nuclei in Pb–Pb Collisions Measured with ALICE at the LHCStefano Piano18 July 2017Formation of Hypernuclei in Relativistic Ion CollisionsAlexander Botvina, Marcus Bleicher, Josef Pochodzalla and Jan Steinheimer18 July 2017Electric dipole moment of the deuteron in the standard model with NN − Λ N − Σ N couplingNodoka Yamanaka1 Jul 2017 | Nuclear Physics A, Vol. 963A study on binding energies of $\Lambda$ Λ hypernucleiS. Pal, R. Ghosh, B. Chakrabarti and A. Bhattacharya13 June 2017 | The European Physical Journal Plus, Vol. 132, No. 6Green's function relativistic mean field theory for Λ hypernucleiS.-H. Ren, T.-T. Sun and W. Zhang22 May 2017 | Physical Review C, Vol. 95, No. 5Single-particle spectral function of the Λ hyperon in finite nucleiIsaac Vidaña1 Feb 2017 | Nuclear Physics A, Vol. 958Formation of hypernuclei in heavy-ion collisions around the threshold energiesA. S. Botvina, K. K. Gudima, J. Steinheimer, M. Bleicher and J. Pochodzalla11 January 2017 | Physical Review C, Vol. 95, No. 1Quest for magicity in hypernucleiM. Ikram, Asloob A. Rather, Bharat Kumar, S. K. Biswal, and S. K. Patra4 January 2017 | International Journal of Modern Physics E, Vol. 25, No. 12Formation of hypernuclei in evaporation and fission processesA. S. Botvina, N. Buyukcizmeci, A. Ergun, R. Ogul and M. Bleicher et al.15 November 2016 | Physical Review C, Vol. 94, No. 5The structure of hypernuclei and hyperon mixing in neutron-star matterE Hiyama, Y Yamamoto and H Sagawa27 July 2016 | Physica Scripta, Vol. 91, No. 9Relativistic ion collisions as the source of hypernucleiA. S. Botvina, M. Bleicher, J. Pochodzalla and J. Steinheimer22 August 2016 | The European Physical Journal A, Vol. 52, No. 8Non-relativistic s-wave binding energies of Λ-particle in hypernucleiA. Armat and H. Hassanabadi5 May 2016 | Modern Physics Letters A, Vol. 31, No. 14Low-energy hypernuclear spectra within a microscopic particle-rotor model with a relativistic point-coupling hyperon-nucleon interactionH. Mei, K. Hagino, J. M. Yao and T. Motoba12 April 2016 | Physical Review C, Vol. 93, No. 4HΛ3 and H‾Λ¯3 production in Pb–Pb collisions at sNN=2.76 TeVJ. Adam, D. Adamová, M.M. Aggarwal, G. Aglieri Rinella and M. Agnello et al.1 Mar 2016 | Physics Letters B, Vol. 754Recent results from strangeness in transport modelsJ. Steinheimer, A.S. Botvina and M. Bleicher18 January 2016 | Journal of Physics: Conference Series, Vol. 668Generator coordinate method for hypernuclear spectroscopy with a covariant density functionalH. Mei, K. Hagino and J. M. Yao8 January 2016 | Physical Review C, Vol. 93, No. 1Experimental review of hypernuclear physics: recent achievements and future perspectivesA Feliciello and T Nagae28 August 2015 | Reports on Progress in Physics, Vol. 78, No. 9Microscopic study of low-lying spectra of Λ hypernuclei based on a beyond-mean-field approach with a covariant energy density functionalH. Mei, K. Hagino, J. M. Yao and T. Motoba8 June 2015 | Physical Review C, Vol. 91, No. 6Effects of isovector scalar δ–meson on Λ–hypernucleiM. Ikram, S. K. Singh, S. K. Biswal, and S. K. Patra26 March 2015 | International Journal of Modern Physics E, Vol. 24, No. 03Formation of hypermatter and hypernuclei within transport models in relativistic ion collisionsA.S. Botvina, J. Steinheimer, E. Bratkovskaya, M. Bleicher and J. Pochodzalla1 Mar 2015 | Physics Letters B, Vol. 742Hypervirial approach applied to multi-cluster nuclear systemsR M Adam, S A Sofianos, M L Lekala and G J Rampho11 December 2014 | Journal of Physics G: Nuclear and Particle Physics, Vol. 42, No. 2Microscopic particle-rotor model for the low-lying spectrum of Λ hypernucleiH. Mei, K. Hagino, J. M. Yao and T. Motoba1 December 2014 | Physical Review C, Vol. 90, No. 6Experiments with the High Resolution Kaon Spectrometer at JLab Hall C and the new spectroscopy of Λ12B hypernucleiL. Tang, C. Chen, T. Gogami, D. Kawama and Y. Han et al.25 September 2014 | Physical Review C, Vol. 90, No. 3Extended quark mean-field model for neutron starsJ. N. Hu, A. Li, H. Toki and W. Zuo5 February 2014 | Physical Review C, Vol. 89, No. 2Production of hypernuclei in peripheral relativistic ion collisionsA. S. Botvina, K. K. Gudima and J. Pochodzalla7 November 2013 | Physical Review C, Vol. 88, No. 5A New Determination of the Lambda-Nucleon Coupling Constants in Relativistic Mean Field TheoryXiao-Su Wang, Hong-Yi Sang, Jia-Hui Wang and Hong-Feng Lü31 October 2013 | Communications in Theoretical Physics, Vol. 60, No. 4Probable alpha and 14C cluster emission from hyper Ac nucleiK. P. Santhosh21 October 2013 | The European Physical Journal A, Vol. 49, No. 10Mechanisms for the production of hypernuclei beyond the neutron and proton drip linesN. Buyukcizmeci, A. S. Botvina, J. Pochodzalla and M. Bleicher24 July 2013 | Physical Review C, Vol. 88, No. 1Four-body structure of neutron-rich hypernucleus 6ΛHE. Hiyama, S. Ohnishi, M. Kamimura and Y. Yamamoto1 Jun 2013 | Nuclear Physics A, Vol. 908Possible Existence of Light HypernucleiT. Yamada and K. Ikeda17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Widths of Hypernuclear StatesD. J. Millener, C. B. Dover and A. Gal17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Treatment of Pauli Exclusion Operator in G-Matrix Calculations for HypernucleiT. T. S. Kuo and J. Hao17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Selected Topics in Spectroscopy of -Hypernuclei and Hyperon-Nucleon InteractionsV. N. Fetisov17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Pi-Mesonic Weak Decay Rates of Light-to-Heavy HypernucleiT. Motoba and K. Itonaga17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Weak Decays and Polarization of HypernucleiT. Kishimoto and H. Ejiri17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Hypernuclear Spectroscopy: Progress, Problems and Unexplored PossibilitiesL. Majling and R. A. Eramzhyan17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Hypernuclear Production in High-Energy Nuclear CollisionsM. Sano and M. Wakai17 May 2013 | Progress of Theoretical Physics Supplement, Vol. 117, No. 0Weak Hyperon-Nucleon Interaction in a Quark Model and Application to the pn -> p ScatteringT. Inoue, K. Sasaki, S. Takeuchi and M. Oka16 May 2013 | Progress of Theoretical Physics Supplement, Vol. 137, No. 0STRANGE BARYONS, NUCLEAR DRIPLINE AND SHRINKAGE: A RELATIVISTIC MEAN FIELD STUDYBIPASHA BHOWMICK, ABHIJIT BHATTACHARYYA, and G. GANGOPADHYAY27 March 2013 | International Journal of Modern Physics E, Vol. 22, No. 03Few-Body Aspects of Hypernuclear PhysicsEmiko Hiyama29 February 2012 | Few-Body Systems, Vol. 53, No. 3-4Neutron-rich hypernuclei in the chiral soliton modelV. B. Kopeliovich24 October 2012 | JETP Letters, Vol. 96, No. 4GROUND STATES AND EXCITED STATES OF HYPERNUCLEI IN RELATIVISTIC MEAN FIELD APPROACHBIPASHA BHOWMICK, ABHIJIT BHATTACHARYYA, and G. GANGOPADHYAY24 July 2012 | International Journal of Modern Physics E, Vol. 21, No. 07A study of Λ hypernuclei within the Skyrme–Hartree–Fock modelNeelam Guleria, Shashi K. Dhiman and Radhey Shyam1 Jul 2012 | Nuclear Physics A, Vol. 886IMPURITY EFFECT OF Λ HYPERON ON SHAPE-COEXISTENCE NUCLEUS 44S IN THE ENERGY FUNCTIONAL BASED COLLECTIVE HAMILTONIANH. MEI, Z. P. LI, J. M. YAO, and K. HAGINO30 May 2012 | International Journal of Modern Physics E, Vol. 21, No. 05Strange hadronic physics in electroproduction experiments at the Mainz MicrotronP. Achenbach, A. Esser, C. Ayerbe Gayoso, R. Böhm and O. Borodina et al.1 May 2012 | Nuclear Physics A, Vol. 881Electromagnetic production of medium-mass Λ-hypernucleiP. Bydžovský, M. Sotona, T. Motoba, K. Itonaga and K. Ogawa et al.1 May 2012 | Nuclear Physics A, Vol. 881Strangeness nuclear physics: a critical review on selected topicsElena Botta, Tullio Bressani and Gianni Garbarino30 March 2012 | The European Physical Journal A, Vol. 48, No. 3Microscopic approach to the proton asymmetry in the nonmesonic weak decay of Λ hypernucleiE. Bauer, G. Garbarino, A. Parreño and A. Ramos27 February 2012 | Physical Review C, Vol. 85, No. 2Impurity effect of Lambda hyperon on collective excitations of nuclear core in MgΛ25J.M. Yao, Z.P. Li, K. Hagino, M.Thi Win and Y. Zhang et al.1 Oct 2011 | Nuclear Physics A, Vol. 868-869A RENORMALIZED HVT APPROACH AND ENERGIES OF A Λ-PARTICLE IN HYPERNUCLEIC. A. EFTHIMIOU, M. E. GRYPEOS, C. G. KOUTROULOS, K. J. OYEWUMI, and TH. PETRIDOU2 May 2012 | International Journal of Modern Physics E, Vol. 20, No. 06Hypernuclear SpectroscopyF Garibaldi, O Hashimoto, J J LeRose, P Markowitz and S N Nakamura et al.8 June 2011 | Journal of Physics: Conference Series, Vol. 299Production of excited double hypernuclei via Fermi breakup of excited strange systemsAlicia Sanchez Lorente, Alexander S. Botvina and Josef Pochodzalla1 Mar 2011 | Physics Letters B, Vol. 697, No. 3Ξ12C(0+) AND Ξ16O POTENTIALS DERIVED FROM THE SU6 QUARK-MODEL BARYON-BARYON INTERACTIONY. Fujiwara, M. Kohno, and Y. Suzuki25 January 2012 | International Journal of Modern Physics E, Vol. 19, No. 12MESON EXCHANGE MODEL WITH THE AXIAL VECTOR A1-MESON EXCHANGE AND HYPERNUCLEAR NONMESONIC DECAY ASYMMETRIESK. Itonaga, T. Motoba, Th. A. Rijken, and T. Ueda25 January 2012 | International Journal of Modern Physics E, Vol. 19, No. 12HYPERNUCLEUS PRODUCTION AT RHIC AND HIRFL-CSR ENERGYSONG ZHANG, J. H. CHEN, Y. G. MA, Z. B. TANG, and Z. B. XU25 January 2012 | International Journal of Modern Physics E, Vol. 19, No. 08n09A relativistic description of the reactionS. Bender, R. Shyam and H. Lenske1 Aug 2010 | Nuclear Physics A, Vol. 839, No. 1-4Λ hypernuclei and neutron star matter in a chiral SU( 3 ) relativistic mean field model with a logarithmic potentialK. Tsubakihara, H. Maekawa, H. Matsumiya and A. Ohnishi22 June 2010 | Physical Review C, Vol. 81, No. 6Model for hypernucleus production in heavy ion collisionsV. Topor Pop and S. Das Gupta28 May 2010 | Physical Review C, Vol. 81, No. 5Study of the reactionM. Agnello, L. Benussi, M. Bertani, H.C. Bhang and E. Bonifazi et al.1 Apr 2010 | Nuclear Physics A, Vol. 835, No. 1-4Structure and production of p-shell Ξ-hypernucleiT. Motoba and S. Sugimoto1 Apr 2010 | Nuclear Physics A, Vol. 835, No. 1-4Structure of light hypernucleiE. Hiyama and T. Yamada1 Oct 2009 | Progress in Particle and Nuclear Physics, Vol. 63, No. 2Nuclear capture at rest of Ξ− hyperonsS. Aoki, S.Y. Bahk, S.H. Chung, H. Funahashi and C.H. Hahn et al.1 Sep 2009 | Nuclear Physics A, Vol. 828, No. 3-4Photoproduction of hypernuclei within the quark–meson coupling modelR. Shyam, K. Tsushima and A.W. Thomas1 Jun 2009 | Physics Letters B, Vol. 676, No. 1-3P-WAVE ΛN-ΣN COUPLING AND THE SPIN-ORBIT SPLITTING OF $_\Lambda^9 {\rm{Be}}$Y. FUJIWARA, M. KOHNO, and Y. SUZUKI21 November 2011 | Modern Physics Letters A, Vol. 24, No. 11n13Properties of deformed Λ hypernucleiZhou Xian-Rong13 May 2009 | Chinese Physics C, Vol. 33, No. S1Feasibility of extracting a Σ− admixture probability in the neutron-rich Λ10Li hypernucleusT. Harada, A. Umeya and Y. Hirabayashi9 January 2009 | Physical Review C, Vol. 79, No. 1PROPERTIES OF NUCLEI AND HYPERNUCLEI WITH THE DEFORMED SKYRME HARTREE-FOCK MODELXIAN-RONG ZHOU, H.-J. SCHULZE, and H. SAGAWA25 January 2012 | International Journal of Modern Physics E, Vol. 17, No. supp01Research program of the NIS-GIBS project at JINR NuclotronE. A. Strokovsky4 December 2008 | Few-Body Systems, Vol. 44, No. 1-4A particle–hole model approach for hypernucleiM. Martini, V. De Donno, C. Maieron and G. Co'1 Dec 2008 | Nuclear Physics A, Vol. 813, No. 3-4Studying of hypernuclei with nuclotron beamsA. V. Averyanov, S. A. Avramenko, V. D. Aksinenko, M. Kh. Anikina and S. N. Bazylev et al.8 January 2009 | Physics of Atomic Nuclei, Vol. 71, No. 12Extreme Exotic Calcium Lambda Hypernuclei in the Relativistic Continuum Hartree—Bogoliubov TheoryLü Hong-Feng3 October 2008 | Chinese Physics Letters, Vol. 25, No. 10MESIC ATOMS AND MESIC NUCLEISATORU HIRENZAKI21 November 2011 | Modern Physics Letters A, Vol. 23, No. 27n30Production of hypernuclei with hadronic and electromagnetic probesR. Shyam1 Jul 2008 | Progress in Particle and Nuclear Physics, Vol. 61, No. 1Lambda hyperonic effect on the normal drip linesC Samanta, P Roy Chowdhury and D N Basu22 April 2008 | Journal of Physics G: Nuclear and Particle Physics, Vol. 35, No. 6A theoretical overview of hypernuclear weak decayC. Chumillas, G. Garbarino, A. Parreño and A. Ramos1 May 2008 | Nuclear Physics A, Vol. 804, No. 1-4Hypernuclear spectroscopy program at JLab Hall CO. Hashimoto, S.N. Nakamura, A. Acha, A. Ahmidouch and D. Androic et al.1 May 2008 | Nuclear Physics A, Vol. 804, No. 1-4Core Polarization and Tensor Coupling Effects on Magnetic Moments of HypernucleiYao Jiang-Ming, Lü Hong-Feng, Hillhouse Greg and Meng Jie9 May 2008 | Chinese Physics Letters, Vol. 25, No. 5Hypernuclear production by the ( γ,K+ ) reaction within a relativistic modelR. Shyam, H. Lenske and U. Mosel12 May 2008 | Physical Review C, Vol. 77, No. 5Hypernuclei and in-medium chiral dynamicsP. Finelli1 Apr 2008 | The European Physical Journal Special Topics, Vol. No. in the deformed H.-J. H. and September | Physical Review C, Vol. No. from hypernuclei Λ H and Λ Majling and Sep | Physics of Atomic Nuclei, Vol. No. and heavy hypernuclei in chiral soliton B. and A. M. August | The European Physical Journal A, Vol. 33, No. of hypernuclei in of nuclear S. Botvina and J. August | Physical Review C, Vol. No. in the SU6 quark model and their to light nuclear Fujiwara, Y. and C. Apr | Progress in Particle and Nuclear Physics, Vol. No. in the chiral dynamics of Λ in nuclear and M. J. March | Physical Review C, Vol. No. of Hypernuclei with Jan model analysis of the formation Kohno, Y. Fujiwara, Y. K. and M. December | Physical Review C, Vol. No. of Λ and H. Oct | Progress in Particle and Nuclear Physics, Vol. No. the weak decay of Λ and Λ B hypernucleiL. V. A. and T. V. May | Physics of Atomic Nuclei, Vol. No. spectrum in the reaction on and the Harada and Yoshiharu Mar | Nuclear Physics A, Vol. for and hypernuclei with symmetry Samanta, P Roy Chowdhury and D N February | Journal of Physics G: Nuclear and Particle Physics, Vol. No. 3A relativistic model for Shyam, H. Lenske and U. Jan | Nuclear Physics A, Vol. in the Weak Decay of Λ M. G. Garbarino, A. Parreño and A. Ramos1 March | Physical Review Letters, Vol. 94, No. and nonmesonic weak decay of Λ S. K. Aoki, H. Bhang and T. et February | Physical Review C, Vol. 71, No. 2Production of the in the K. T. W. J. K. and S. et February | Physical Review Letters, Vol. 94, No. dynamics and Λ in the nuclear and W. January | Physical Review C, Vol. 71, No. for the in production from Harada and Yoshiharu Nov | Nuclear Physics A, Vol. with the reaction on nuclear K. H. D. S. and K. et October | Physical Review C, Vol. No. of Λ and Λ B hypernuclei: analysis and of nuclear V. A. and T. V. Oct | Physics of Atomic Nuclei, Vol. No. of 3α and using method Fujiwara, K. M. Kohno, Y. and D. et August | Physical Review C, Vol. No. Nuclear on J. and P. Apr | Physica Ion Physics, Vol. 19, No. of Λ hypernuclei via and D. E. Sep | Physics of Atomic Nuclei, Vol. No. in E. and N. July | Physical Review C, Vol. No. hypernuclei as chiral Jun | Nuclear Physics A, Vol. as chiral B. May | Journal of Experimental and Theoretical Physics, Vol. 96, No. decay of Λ hypernuclei in a J. E. and J. March | Physical Review C, Vol. No. in Hypernuclei in the Relativistic Continuum Hong-Feng and Meng November | Chinese Physics Letters, Vol. 19, No. decay of and G. Oct | Physics Vol. No. of Λ hypernuclei in the quark mean-field and H. Sep | Nuclear Physics A, Vol. No. of and in nuclear matter based on relativistic chiral and Mar | Nuclear Physics A, Vol. No. and recent hyperon-nucleon S. Y. and T. T. S. March | Physical Review C, Vol. No. ON THE AND OF IN HYPERNUCLEI FROM E. GRYPEOS, C. G. KOUTROULOS, and TH. A. April 2012 | International Journal of Modern Physics E, Vol. No. and hyperon and D et July | Journal of Physics G: Nuclear and Particle Physics, Vol. No. for the nonmesonic weak decay of the hypernuclei and March | Physical Review C, Vol. 63, No. of in the nonmesonic decay of light hypernucleiK. Hagino and A. March | Physical Review C, Vol. 63, No. approach to hypernuclear and J November | Journal of Physics G: Nuclear and Particle Physics, Vol. No. in and November density for the Pauli in S Y T T S Kuo and H October | Journal of Physics G: Nuclear and Particle Physics, Vol. No. in the with a microscopic hyperon-nucleon Cugnon, A. and H.-J. November | Physical Review C, Vol. No. of light nuclei and hyperon Yamada and August | Physical Review C, Vol. No. of and heavy hypernuclei with the = p and and M. Jul | The European Physical Journal A, Vol. No. from Kohno, Y. Fujiwara, T. C. and Y. Jul | Nuclear Physics A, Vol. No. mixing in finite and J R June | Journal of Physics G: Nuclear and Particle Physics, Vol. No. and of neutron star A. A. L. and M. July | Physical Review C, Vol. No. production from capture in Jun | Nuclear Physics A, Vol. No. of in the nuclear and E. May | Nuclear Physics A, Vol. No. hadron field theory for M. and H. May | Physical Review C, Vol. 61, No. for hypernuclei and the in the reaction on B. and et al.1 Apr | Physics Letters B, Vol. No. decay of Λ in Sasaki, and Apr | Nuclear Physics A, Vol. No. model for hypernuclei and hyperon-nucleon S. Y. T. T. S. and V. G. D. February | Physical Review C, Vol. 61, No. approach to and and nuclear E. and A. Ramos1 Jan | Progress in Particle and Nuclear Physics, Vol. No. nuclear matter within A. A. M. and V. G. J. January | Physical Review C, Vol. 61, No. of the hypernucleus using S. Y. T. T. S. Kuo and H. August | Physical Review C, Vol. 60, No. for nonmesonic weak decay of Jun and Jul | A, Vol. No. states and at and Jul | Nuclear Physics A, Vol. No. in the

The ability to describe electromagnetic properties of nuclei is fundamental to our understand- ing of nuclear structure and dynamics. Experimental methods that measure these properties enable a clean way to isolate the nuclear physics content, because the relatively weak and well understood electromagnetic interaction is perturbative in nature and thus appropriately described. In this thesis we study electromagnetic properties of light nuclei within the framework of chiral effective field theory (EFT). The modern approach to low-energy nuclear physics is formulated by chiral EFT which describes the nucleus in terms of nucleon and pion degrees of freedom based on the symmetries of the underlying fundamental theory of quantum chromo- dynamics. It provides a systematically improvable calculation scheme and permits a unified description of the strong-interaction dynamics between nucleons and the interaction with an external probe. The nuclear component of such an interaction is described by nuclear currents. Both nuclear interactions and currents are consistently derived within chiral EFT and exhibit a naturally emerging many-body operator structure. Recent progress on the development of nuclear interactions and nuclear currents have set the stage for high-precision calculations complemented with systematic truncation uncertainty estimates. We study the deuteron, the triton, and the helion electromagnetic form factors with two- and three-nucleon chiral interactions developed in an order-by-order manner which allows us to compute the associated truncation uncertainty estimates. We find good agreement at low momentum transfers for the charge form factors and a consistent description of the experimental first minimum once the uncertainty estimates are incorporated. For the tri- nucleon magnetic form factors we find that leading two-body currents (2BCs), which arise from the exchange of a pion between a pair of nucleons, lead to better agreement with data over the entire momentum-transfer region. To obtain insights into the effect of various chiral interactions with and without three-nucleon forces and to quantify the impact of 2BCs on the zero-momentum-transfer region, we analyze the magnetic moments and the electromagnetic radii of these light nuclei. We observe that three-nucleon forces reduce the radii slightly and have a negligible effect on the magnetic moment, while 2BCs significantly modify both the magnetic radius and magnetic moment indicating that the exchange dynamics between the nucleons are essential for magnetic observables. As a first step towards a consistent study of other light nuclei, we examine the magnetic moment and a magnetic transition of 6Li which is the next light nucleus after the three- nucleon nuclei with nonvanishing magnetic ground-state properties. To achieve this, we include contributions to the magnetic dipole operator beyond leading order which arise from the leading 2BCs and we employ similarity renormalization group evolved chiral interactions to enhance the many-body convergence. Our results are in remarkable agreement with a new precision experiment after consistently evolving and including 2BCs to the magnetic dipole operator, thus advancing our understanding of nuclear interactions and electromagnetic currents in many-nucleon systems.

Interacting-electron states and the persistent current in a quantum ring

weak interaction is one of the least understood topics in particle physics. is one of the four kinds of force that physicists recognize in nature, and, as its name indicates, it is much weaker than two of the others, the strong (nuclear) interaction and electromagnetism. has therefore been difficult to study because its effects are usually masked by the two stronger forces. In a few years the world will have at least two particle accelerators with capacities of hundreds of billions of electron-volts energy, and physicists hope that these machines may allow the beginning of a new era of systematic and vigorous investigation of the weak force. There is a finite chance that in our lifetime we'll see something interesting in the weak David B. Cline of the University of Wisconsin told the recent Coral Gables Conference on Fundamental Interactions at High Energy at the University of Miami. first manifestation of the weak interaction that physicists noticed was nuclear beta decay. In beta decay a neutron inside an atomic nucleus turns into a proton, emitting by the way an electron (called in the old days a beta ray) and an antineutrino. In recent years many other particles have been found that decay radioactively under the influence of the weak interaction. From these decay activities alone it is hard to arrive at a good mathematical description of the weak force or to test rival theories. That can be better done by investigating how the force acts in particle collisions in accelerator experiments. But the two stronger forces blot out the effect of the weak force unless one party to the collision is a neutrino. (Neutrinos are the only known kind of particle that responds to the weak force but to neither of the two stronger ones.) To do experiments with neutrinos requires a copious and energetic beam of them. world's two new accelerators (the National Accelerator Laboratory now in operation at Batavia, Ill., and CERN II beginning construction near Geneva) will provide such beams. They may be used to study the weak force itself and to use it as a means of probing the structure of other particles. The new accelerators may very well provide a new era in neutrino spectroscopy, A. K. Mann of NAL told the Coral Gables Conference. It may be the new optics of the remainder of this century. One of the most important questions to be decided by forthcoming experiments is whether the weak force is a local interaction or a nonlocal one. A local interaction is one in which the two interacting particles affect each other directly, rather like two billiard balls colliding. In a nonlocal interaction, the interacting particles exchange an intermediarly particle, and this particle mediates the effect of one to the other. In the strong interaction, the intermediary particle is a virtual meson; in electromagnetism it is a virtual photon. Formulations of both kinds have been suggested for the weak interaction. In the traditional nonlocal formulation, the intermediary is called the intermediate vector boson. Lately some theorists, most prominently T. D. Lee of Columbia University (SN: 10/9/71, p. 252) and Steven Weinberg of Massachusetts Institute of Technology, have been trying to work out a combined theory of the weak interaction plus electromagnetism. In this case there is a family of intermediaries among which both the vector boson and the photon find a place. local formulations arouse dismay because in them the particles most concerned with the weak interaction, the class called leptons (the electron, the muon, the two kinds of neutrino and their respective antiparticles), are point particles; like a formal geometric point, they have zero dimensions. is difficult to visualize a body with mass that does not occupy space, and, when one tries, all sorts of disturbing paradoxes come forth: particles have infinite mass densities, infinite self-energies, infinite electric charge densities and other infinities, some of which appear to be at variance with known properties of the particles. A nonlocal weak interaction allows the particles to occupy space. also does away with the troublesome infinities. Besides its esthetic qualities, what evidence is now in hand tends to incline some people toward the nonlocal theory. The point theory of the weak interaction cannot be exact, says Mann. He and others expect that the inexactness will become clear in the new range of energies about to be opened up. At energies near 300 billion electron-volts (GeV) something new may happen, he suggests. Some structure may appear in the interaction: maybe a vector boson propagator, maybe new kinds of leptons, maybe new neutrinos, maybe higher~~~~~~~~~~~~~~~~~~~~~~~~~~~~~lr i,.,...,...,.~~~~~~~~~~~~~~~~-,-----------------'>.' s