Search

A coupled-channel analysis of BESIII data on radiative $J/\psi$ decays into $\pi\pi$, $K\bar K$, $\eta\eta$ and $\omega\phi$ has been performed. The partial-wave amplitude is constrained by a large number of further data. The analysis finds ten isoscalar scalar mesons. Their masses, widths and decay modes are determined. The scalar mesons are interpreted as mainly SU(3)-singlet and mainly octet states. Octet isoscalar scalar states are observed with significant yields only in the 1500-2100\,MeV mass region. Singlet scalar mesons are produced over a wide mass range but their yield peaks in the same mass region. The peak is interpreted as scalar glueball. Its mass and width are determined to $M=1865$\er25$^{+10}_{-30}$ {\rm MeV} and $\Gamma= 370$\er$50^{+30}_{-20}$ {\rm MeV}, its yield in radiative $J/\psi$ decays to ($5.8\pm 1.0)\,10^{-3}$., Comment: 11 pages, 4 figures

We study the transitions between the different color states of a static quark-antiquark pair, singlet and octet, in a thermal medium. This is done non-perturbatively exploiting the infinite mass limit of QCD. This study is interesting because it can be used for future developments within the framework of Effective Field Theories (EFTs) and because it can be combined with other techniques, like lattice QCD or AdS/CFT, to gain non-perturbative information about the evolution of quarkonium in a medium. We also study the obtained expressions in the large $N_{c}$ limit. This allows us to learn lessons that are useful to simplify phenomenological models of quarkonium in a plasma., 32 pages, 14 figures. Matches published version

We investigate the interaction between a heavy quark-antiquark pair in color octet configuration in a gluon plasma. We calculate nonperturbatively the effective thermal potential for hybrid states with static $Q\overline{Q}$ octet and an adjoint gluonic source. We compare the results for two different gluonic sources, which lead to completely different potentials in the confined phase. We find that they show identical thermal potentials to large distances, and interpret this potential as the interaction potential between the static $Q$ and the $\overline{Q}$ in a color octet configuration. We present results for the potential in gluon plasma for moderately high temperatures $\ensuremath{\lesssim}2{T}_{c}$. The implications of our result are discussed.

In this work we consider the axial-vector form factors of the nucleon in flavor-SU(2) and of the baryon octet in flavor-SU(3) Chiral Perturbation Theory. We include the Δ-isobar and the baryon decuplet as explicit degrees of freedom and focus on their consistent treatment in terms of chiral power counting. We employ the use of on-shell meson and baryon masses in the one-loop contributions to the axial-vector form factors. The convergence properties of such an approach are scrutinized. Our results are compared to the available flavor-SU(2) QCD lattice data.

Based on 4.481 x 10(8) psi(3686) events collected with the BESIII detector at BEPCII, the branching fraction of the isospin violating decay psi(3686)-> (Sigma) over bar0 Lambda+c.c: is measured to be (1.60 +/- 0.31 +/- 0.13 +/- 0.58) x 10(-6), where the first uncertainty is statistical, the second is systematic, and the third is the uncertainty arising from interference with the continuum. This result is significantly smaller than the measurement based on CLEO-c data sets. The decays chi cJ ->Lambda(Lambda) over bar are measured via psi(3686)->gamma gamma(cJ), and the branching fractions are determined to be B(chi(c0) -> Lambda(Lambda) over bar) = (3.64 +/- 0.10 +/- 0.10 +/- 0.07) x 10(-4), B(chi(c1) -> Lambda(Lambda) over bar) = (1.31 +/- 0.06 +/- 0.06 +/- 0.03) x 10(-4), B(chi(c2) -> Lambda(Lambda) over bar) = (1.91 +/- 0.08 +/- 0.17 +/- 0.04) x 10(-4), where the third uncertainties are systematic due to the psi(3686) -> gamma chi(cJ) branching fractions.

We employ the flavor SU(3) symmetry to analyze semileptonic decays of anti-triplet charmed baryons ($\Lambda^{+}_{c},\Xi_{c}^{+,0}$) and find that the experimental data on ${\cal B}(\Lambda_c\to\Lambda \ell^+\nu_{\ell})$ implies $\mathcal{B}(\Xi_c^0\to\Xi^-e^+\nu_{e})=(4.10\pm0.46)\%$ and $\mathcal{B}(\Xi_c^0\to\Xi^-\mu^+\nu_{\mu})= (3.98\pm0.57)\%$. When this prediction is confronted with recent experimental results from Belle collaboration $\mathcal{B}(\Xi_c^0\to\Xi^-e^+\nu_e)=1.31(04\pm07\pm38)\%$ and $\mathcal{B}(\Xi_c^0\to\Xi^-\mu^+\nu_{\mu})=1.27(06\pm10\pm 37)\%$, it is found that the SU(3) symmetry is severely broken. We then consider the generic SU(3) breaking effects in these decays and find that the data can be accommodated in different scenarios but the breaking effects are inevitably large. In some interesting scenarios, we also explore the testable implications in these scenarios which can be tested with more data become available. Similar analyses are carried out for semileptonic anti-triplet beauty baryon to octet baryons and anti-triplet charmed baryons. The validity of SU(3) for these decays can also be examined when data become available., Comment: 11 pages, 2 figures and 7 tables

The study of heavy quarkonium suppression in heavy-ion collisions represents an important source of information about the properties of the quark-gluon plasma produced in such collisions. In a previous paper, we have considered how to model the evolution of a quarkonium in such a way that the solution of the resulting equations evolves toward the correct thermal equilibrium distribution for an homogeneous and static medium. We found that it is crucial to take into account the energy gap between singlet and octet configurations when the temperature is not much greater than this energy gap. In this manuscript, we explore in more detail the phenomenological consequences of this observation in the more realistic situation of an expanding system. We consider two different scenarios, based on the same approximation scheme, but on different choices of parameters. In the first case, we rely on a Hard Thermal Loop approximation, while the second case is based on a recent determination of the static potential in lattice QCD. In both cases, we compute the decay width and the nuclear modification factor, both taking the energy gap into account and ignoring it. We find that the impact on the predictions is as large in the expanding medium as it is in the static case. Our conclusion is that this energy gap should be taken into account in phenomenological studies., Published version. 25 pages, 11 figures

Magnetic dipole moment form factor, $G_M^{(2)}(Q^2)$, describing the radial excitation of decuplet baryons to octet baryons electromagnetic transitions as well as the ratios, $R_{SM} = -\frac{1}{4 m_2^2} \sqrt{4 m_2^2 Q^2 + (m_2^2 - Q^2 -m_1^2)^2} \frac{G_C^{(2)}(Q^2)}{G_M^{(2)}(Q^2)}$ and $R_{EM} = -\frac{G_E^{(2)}(Q^2)}{G_M^{(2)}(Q^2)}$ are calculated in the framework of light-cone sum rules. We also estimate the degree of the violation of U-spin symmetry. The obtained results for the multipole form factors can be useful in searching the properties of radially excited baryon states., 21 pages, 7 figures

Le présent mémoire propose une analyse des processus de composition via la mélodie, la polytonalité et la polyrythmie à travers l’improvisation pianistique, pour finir par l’orchestration des cinq pièces musicales composées durant les deux années de la maîtrise en composition instrumentale et vocale à l’Université de Montréal, soit de septembre 2017 à avril 2019. Ces pièces sont un Sextuor, un Octuor, un Mouvement pour deux pianos et percussions, 5 Miniatures pour orchestre et Tristesse de la lune, une mélodie sur un poème de Charles Baudelaire, l’ensemble totalisant 33 minutes de musique. Nous tentons de situer dans un contexte général la place de ces processus à travers les différentes références de l’auteur pour ouvrir le champ des possibilités qu’ils amènent pour le futur., This thesis proposes an analysis of the composition process via melody, polytonality and polyrhythm through piano improvisation, ending with the orchestration of the five musical pieces composed during the two years of the master's in instrumental and vocal composition at the University of Montreal, from September 2017 to April 2019. These pieces are a Sextet, an Octet, a Movement for two pianos and percussions, 5 Miniatures for orchestra and Tristesse de la lune, a melody on a poem by Charles Baudelaire, totaling 33 minutes of music. We try to situate in a general context the place of these processes through the different references of the author to open fields of possibilities they bring to the future.

In this paper a novel feature descriptor is proposed named coupled bi-orientation octet (COBOT) pattern for medical image retrieval. COBOT enhances the image with octet encoding so that minute features of an image can be utilized for classification and retrieval. Loss of features is comparatively very less in COBOT when compared with other feature descriptors. COBOT can be explained in terms of orientation and octet. Bi orientation refers to both clockwise and anti-clockwise movements whereas, octet property divides the whole image in eight equal patches and extracts information from each of them. COBOT discern and augment the lines, corner point and texture information in the precinct octet across diverse directions. To further improve the robustness, multiresolution Gaussian filters with COBOT is incorporated and it is termed as MEGABOT. The proposed method transcends various other extensively used hand-crafted feature descriptors used for classification and retrieval of biomedical images.

We consider the prompt double $J/\psi$ production in $pp$ collisions at the LHC in the framework of $k_T$-factorization QCD approach. Using the fragmentation mechanism, we evaluate the color octet contributions to the production cross sections taking into account the combinatorial effects of multiple gluon radiation in the initial state driven by the Ciafaloni-Catani-Fiorani-Marchesini evolution equation. We demonstrate the importance of these contributions in a certain kinematical region covered by the CMS and ATLAS measurements. On the other hand, the experimental data taken by the LHCb Collaboration at forward rapidities and moderate transverse momenta can be described well by ${\cal O}(\alpha_s^4)$ color singlet terms and contributions from the double parton scattering mechanism. The extracted value of the effective cross section $\sigma_{\rm eff} = 17.5 \pm 4.1$~mb is compatible with many other estimations based on different final states., Comment: 18 pages, 10 figures

© Copyright owned by the author(s). We present results from the QCDSF/UKQCD collaboration for the transverse spin densities of octet baryons obtained from simulations using Nf = 2+1 flavours of O(a)-improved Wilson fermions. These densities are revealed through an analysis of the electromagnetic and tensor form factors of the octet baryons at two different lattice spacings with pion masses as low as 220 MeV. We find SU(3) flavour-breaking effects of the form factors and use these to extrapolate to the physical mass. Constructing combinations of Fourier transformed form factors reveal non-trivial spin densities in the transverse plane, with similar deformations across the baryon octet.

We analyze the first LHC data on $\chi_{c1}$ and $\chi_{c2}$ polarization obtained very recently by the CMS Collaboration at $\sqrt s = 8$~TeV. We describe the perturbative production of $c\bar c$ pair with $k_T$-factorization approach and use nonrelativistic QCD formalism for the formation of bound states. We demonstrate that the polar anisotropy of $\chi_{c1}$ and $\chi_{c2}$ mesons is strongly sensitive to the color octet contributions. We extract the long-distance matrix elements for $\chi_{c1}$ and $\chi_{c2}$ mesons from the first CMS polarization measurement %on the polarization parameters $\lambda_{\theta}^{\chi_{c1}}$ and $\lambda_{\theta}^{\chi_{c2}}$ obtained at $\sqrt s = 8$~TeV together with available LHC data on the $\chi_{c1}$ and $\chi_{c2}$ transverse momentum distributions (and their ratios) collected at $\sqrt s = 7$~TeV. Our fit points to unequal color singlet wave functions of $\chi_{c1}$ and $\chi_{c2}$ states., Comment: 12 pages, 5 figures, 1 table

We investigate the electromagnetic transition form factors of the baryon decuplet to the baryon octet, based on the self-consistent SU(3) chiral quark-soliton model, taking into account the effects of explicit breaking of flavor SU(3) symmetry. We emphasize the $Q^2$ dependence of the electromagnetic $N\to \Delta$ transition form factors and the ratios of $E2/M1$ and $C2/M1$ in comparison with the experimental and empirical data. In order to compare the present results of the electromagnetic transition form factors of the $N\to \Delta$ with those from lattice QCD, we evaluate the form factors with the pion mass deviated from its physical value. The results of the $E2/M1$ and $C2/M1$ ratios are in good agreement with the lattice data. We also present the results of the electromagnetic transition form factors for the decuplet to the octet transitions., Comment: 25 pages and 11 figures. The text has been reorganized

The electromagnetic form factors of octet baryons are investigated with the nonlocal chiral effective theory. The nonlocal interaction generates both the regulator, which makes the loop integral convergent, and the Q2 dependence of form factors at tree level. Both octet and decuplet intermediate states are included in the one-loop calculation. The momentum dependence of baryon form factors is studied up to 1 GeV2 with the same number of parameters as for the nucleon form factors. The obtained magnetic moments of all the octet baryons as well as the radii are in good agreement with the experimental data and/or lattice simulation.

In the last years it became possible to measure in HADES the dilepton decays of several baryons. The baryon dilepton decays provide information about the electromagnetic structure of the baryons in the timelike region. In the present work, we study the B′→e+e−B decays, where B′ is a baryon decuplet member and B is a baryon octet member. Our calculations are based on the covariant spectator quark model, where the contribution of the quark core is complemented with an SU(3) contribution from the pion cloud. The pion cloud contribution prove to be relevant in the range of study. We present predictions for the Σ0(1385)→e+e−Λ(1116) and Σ+(1385)→e+e−Σ+(1193) decays, which may be tested at HADES in a near future. Predictions for the remaining decuplet baryon Dalitz decays are also presented. We conclude that different orders of magnitudes are expected for the baryon decuplet Dalitz decay widths, according to the quark content of the baryons. We also conclude that the dependence of the transition form factors on the square momentum transfer (q2) is important for some transitions.

The pseudoscalar meson-baryon octet interaction is studied within a nonlinear realized Lagrangian, and then the Bethe-Salpeter equation is solved in the unitary coupled-channel approximation. In sector of strangeness $S=-1$ and isospin $I=0$, only one pole is generated dynamically in the 1400MeV region, which might correspond to the $\Lambda(1405)$ particle. When the case of strangeness zero is studied, the $s-$ and $u-$ potentials are taken into account in the kernel, and a resonance state is produced in the 1500MeV region, which might be a counterpart of the N(1535) particle., Comment: 5 pages. Talk given at the XVIII International Conference on Hadron Spectroscopy and Structure(HADRON2019), August 16-21, Guilin, China

We study the processes $e^+ e^- \to Y(4260) \to J/\psi \pi\pi(K\bar{K})$. The strong final-state interactions, especially the coupled-channel ($\pi\pi$ and $K\bar{K}$) final-state interaction in the $S$-wave are taken into account in a model-independent way using dispersion theory. It is found that the light-quark SU(3) octet state plays a significant role in these transitions, implying that the $Y(4260)$ contains a large light-quark component. Our findings suggest that the $Y(4260)$ is neither a hybrid nor a conventional charmonium state. Furthermore, through an analysis of the ratio of the light-quark SU(3) octet and singlet components, we show that the $Y(4260)$ does not behave like a pure $\bar D D_1$ hadronic molecule as well.

An octet-truss structure is considered as one of promising candidates for modern heat exchanger structures due to its light weight with stress supporting structure and high thermal performance as a multifunctional heat exchanger. A design strategy has been established to control the anisotropy of its effective thermal conductivity tensor by deforming the structure according to its specific heat transfer application. The solution surface of flat triangle was constructed in the space with three coordinate axes being the principal components of the effective thermal conductivity, using the analytical expressions derived for metal frame structures of low solidity. The design parameters of two structural angles can readily be found from this analytical solution surface with equal angle lines to transfer heat in a particular direction, or to block heat in any other direction. Full three-dimensional (3D) numerical computations were also conducted to verify the validity of the present analytical strategy.

In this work we study the collider phenomenology of color-octet scalars (sgluons) in minimal supersymmetric models endowed with a global continuous $R$ symmetry. We systematically catalog the significant decay channels of scalar and pseudoscalar sgluons and identify novel features that are natural in these models. These include decays in nonstandard diboson channels, such as to a gluon and a photon; three-body decays with considerable branching fractions; and long-lived particles with displaced vertex signatures. We also discuss the single and pair production of these particles and show that they can evade existing constraints from the Large Hadron Collider, to varying extents, in large regions of reasonable parameter space. We find, for instance, that a 725 GeV scalar and a 350 GeV or lighter pseudoscalar can still be accommodated in realistic scenarios., 33 pages, 14 figures. Updated to resemble JHEP Version of Record

In quantum chromodynamics (QCD), the role which topologically nontrivial configurations play in splitting the singlet pseudo-Goldstone meson, the η′, from the octet is familiar. In addition, such configurations contribute to other processes which violate the axial U(1)A symmetry. While the nature of topological fluctuations in the vacuum is still unsettled, at temperatures above that for the chiral phase transition, they can be described by a dilute gas of instantons. We show that instantons of arbitrary topological charge Q generate anomalous interactions between 2Nf|Q| quarks, which for Q=1 make the η′ heavy. For two flavors we compute an anomalous quartic meson coupling and discuss its implications for the phenomenology of the chiral phase transition. A dilute instanton gas suggests that for cold, dense quarks, instantons do not evaporate until very high densities, when the baryon chemical potential is ≳2 GeV.

We consider a color octet scalar particle and its exotic decay in the channel gluon-$\gamma$ using an effective Lagrangian description for its strong and electromagnetic interactions. Such a state is present in many extensions of the Standard Model, and in particular in composite Higgs models with top partial compositeness, where couplings to photons arise via the Wess-Zumino-Witten term. We find that final states with one or two photons allow for a better reach at the LHC, even for small branching ratios. Masses up to $1.2$ TeV can be probed at the HL-LHC by use of all final states. Finally, we estimate the sensitivity of the hadronic FCC., Comment: 26 pages, 13 figures, 7 tables, 2 appendices; v2: Discussion in Sec. 2.2 extended, table 2 added, typos fixed, version published in JHEP

The nuclear $p_\perp$-broadening of Drell-Yan and quarkonium ($J/\psi$, $\Upsilon$) production in $\pi$A and pA collisions is investigated. The world data follow a simple scaling from SPS to LHC energies, once the process-dependent color factors are properly taken into account, which allows for the extraction of the transport coefficient in cold nuclear matter. We find that $\hat{q}(x)\propto x^{-\alpha}$ with $\alpha=0.25$-$0.30$. The magnitude of the transport coefficient at $x=10^{-2}$ is $\hat{q}_0=0.051$ GeV$^2$/fm and $\hat{q}_0=0.075$ GeV$^2$/fm, whether $Q\bar{Q}$ pairs are assumed to be produced as color octet or color singlet states, respectively. The relation between nuclear broadening data and the (CT14) gluon density is also investigated., Comment: 22 pages, 5 figures

Octet-truss lattice structures can be used for lightweight structural applications due to their high strength-to-density ratio. In this research, octet-truss lattice specimens were fabricated by stereolithography additive manufacturing with a photopolymer resin. The mechanical properties of this structure have been examined in three orthogonal orientations under the compressive load. Detailed comparison and description were carried out on deformation mechanisms and failure modes in different lattice orientations. Finite element models using both beam elements and three-dimensional solid elements were used to simulate the compressive response of this structure. Both the load reaction and collapse modes obtained in simulations were compared with test results. Our results indicate that three-dimensional continuum element models are required to accurately capture the behaviour of real trusses, taking into account the effects of finite-sized beams and joints.

We consider the quark-mass dependence of the baryon octet and decuplet ground state masses. It is predicted that QCD dynamics implies a first order transition when increasing the strange quark mass from its chiral limit towards its physical value. Our claim relies on a global fit to the available QCD lattice data on such baryon masses. Quantitative results based on an application of the chiral SU(3) Lagrangian at N$^3$LO are discussed. We predict an anomalous sector of QCD where stable baryonic matter would be composed of lambda or anti-lambda particles rather than nucleons and anti-nucleons., slight revision of 4 pages, two updated figures

Many decays of light baryons consisting of light $u,d,s$ quarks have been measured, and these measurements will help us to understand the decay properties of light baryons. In this work, we study two-body nonleptonic weak decays of light baryon octet $(T_8)$ and baryon decuplet $(T_{10})$ by the topological diagram approach (TDA) under the SU(3) flavor symmetry for the first time. We find that (1) the TDA and the SU(3) irreducible representation approach (IRA) match consistently in $T_{10}\to T^{(')}_{8,10}P_8$ ($P_8$ is the light pseudoscalar meson octet); (2) almost all relevant not-yet-measured $\mathcal{B}(T_{10}\to T_8 P_8)$ may be predicted by using three experimental data of $\mathcal{B}(\Omega^-\to \Xi^0\pi^-,\Xi^-\pi^0,\Lambda^0K^-)$, and the upper limits of $\mathcal{B}(T_{10}\to T{'}_{10}\pi^-)$ may be obtained from the experimental upper limit of $\mathcal{B}(\Omega^-\to \Xi^{*0}\pi^-)$ by both the TDA and the IRA together, nevertheless, all new predicted branching ratios are too small to br reached in current experiments; (3) $T_8\to T'_8 P_8$ decays are quite complex in terms of the TDA, and we find that W-exchange diagrams give large and even dominant contributions by using relevant experimental data and the isospin relations., Comment: 14 pages, 1 figure

A non-perturbative calculation of the effective thermal potential between heavy $Q$ and $\bar Q$ from lattice QCD is difficult, and usually involves a Bayesian analysis. Here we present a simple method to obtain the potential from smeared Wilson loop, using the structure of the thermal Wilson loop. We present results for the $Q \bar Q$ thermal potential in a gluonic plasma for temperatures $\lesssim 2 T_c$. We also present preliminary results for the effective potential when the $Q$ and $\bar Q$ are in octet color configuration., 7 pages, 5 figures, contribution to Lattice 2019

We use covariant density functional theory to obtain the equation of state (EoS) of matter in compact stars at non-zero temperature, including the full baryon octet as well as the $\Delta(1232)$ resonance states. Global properties of hot $\Delta$-admixed hypernuclear stars are computed for fixed values of entropy per baryon ($S/A$) and lepton fraction ($Y_L$). Universal relations between the moment of inertia, quadrupole moment, tidal deformability, and compactness of compact stars are established for fixed values of $S/A$ and $Y_L$ that are analogous to those known for cold catalyzed compact stars. We also verify that the $I$-Love-$Q$ relations hold at finite temperature for constant values of $S/A$ and $Y_L$., Comment: 20 pages, 15 figures

A continuum approach to the three valence-quark bound-state problem in quantum field theory, employing parametrisations of the necessary kernel elements, is used to compute the spectrum and Poincarö- covariant wave functions for all flavour-SU(3) octet and decuplet baryons and their first positive-parity ex citations. Such analyses predict the existence of nonpointlike, dynamical quark-quark (diquark) correlations within all baryons; and a uniformly sound description of the systems studied is obtained by retaining flavour- antitriplet-scalar and flavour-sextet-pseudovector diquarks. The analysis predicts the existence of positive- parity excitations of the 𝚵, 𝚵*, Ω baryons, with masses, respectively (in GeV): 1.84(08), 1.89(04), 2.05(02). These states have not yet been empirically identified. This body of analysis suggests that the expression of emergent mass generation is the same in all u, d, s baryons and, notably, that dynamical quark-quark correla tions play an essential role in the structure of each one. It also provides the basis for developing an array of predictions that can be tested in new generation experiments.

We perform a general SU(3)$_F$ analysis of $b\rightarrow c\bar{c}s(d)$ decays of members of the beauty baryon antitriplet to a member of the light baryon octet and a singlet. Under several reasonable assumptions we found $\left\vert \mathcal{A}(\Xi_b^0\rightarrow \Lambda S)/ \mathcal{A}(\Xi_b^0\rightarrow \Xi^0 S)\right\vert\approx 1/\sqrt{6}\, \left\vert V_{cb}^* V_{cd} / (V_{cb}^* V_{cs})\right\vert$ and $\left\vert\mathcal{A}(\Lambda_b\rightarrow \Sigma^0 S)/\mathcal{A}(\Lambda_b\rightarrow \Lambda S)\right\vert \sim 0.02$. These two relations have been recently probed by LHCb for the case of $S=J/\psi$. The former agrees with the measurement, while for the latter our prediction lies close to the upper bound set by LHCb., Comment: 28 pages. Additional references and clarifications. Conclusions unchanged

The axial-vector form factors and axial-vector constants of the baryon decuplet are investigated within a pion mean-field approach, which is also known as the chiral quark-soliton model. Given an axial-vector current with a specified flavor, there are four different form factors of a decuplet baryon. When we consider the singlet, triplet, and octet axial-vector currents, we have twelve different form factors for each member of the baryon decuplet. We compute all these axial-vector form factors of the baryon decuplet, taking into account the rotational $1/N_c$ corrections and effects of flavor SU(3) symmetry breaking. We find that, for a given flavor, two of the form factors for a decuplet baryon are only independent within the present approach. We first examine properties of the axial-vector form factors of the $\Delta^+$ isobar and $\Omega^-$ hyperon. We also compare the results of the triplet axial-vector form factors of $\Delta^+$ with those from lattice QCD and those of the present work for the axial-vector constants of the baryon decuplet with the lattice data. All the results for other members of the baryon decuplet are then presented. The results of the axial charges are compared with those of other works. The axial masses and axial radii are also discussed., Comment: 31 pages, 14 figures

Understanding the nature of the baryon spectrum will provide useful insight in the non-perturbative regime of quantum chromodynamics. Significant progress has been made in the N* regime, but little is known about doubly-strange hyperons. Most knowledge of the Cascade baryons stems from kaon-nucleon experiments from the 1960s and 1970s or the more recent CLAS experiment at Jefferson Lab. This research studies doubly-strange baryons via photoproduction using the GlueX experiment at Jefferson Lab. The Cascade octet ground state Ξ− can be studied in exclusive t-channel production in the reaction γp → KY* → K+(Ξ−K+) with the subsequent decay of the Ξ− into Λπ−. The production model suggests the intermediate hyperon Y* is broad and possibly consists of overlapping states. With GlueX Phase-I data taking concluded, preliminary total cross section results of the Cascade ground state Ξ−(1320) are presented. An exploration into the reaction Ξ−* → K−Λ is also shown.

Taxonomies have found wide applications in various domains, especially online for item categorization, browsing, and search. Despite the prevalent use of online catalog taxonomies, most of them in practice are maintained by humans, which is labor-intensive and difficult to scale. While taxonomy construction from scratch is considerably studied in the literature, how to effectively enrich existing incomplete taxonomies remains an open yet important research question. Taxonomy enrichment not only requires the robustness to deal with emerging terms but also the consistency between existing taxonomy structure and new term attachment. In this paper, we present a self-supervised end-to-end framework, Octet, for Online Catalog Taxonomy EnrichmenT. Octet leverages heterogeneous information unique to online catalog taxonomies such as user queries, items, and their relations to the taxonomy nodes while requiring no other supervision than the existing taxonomies. We propose to distantly train a sequence labeling model for term extraction and employ graph neural networks (GNNs) to capture the taxonomy structure as well as the query-item-taxonomy interactions for term attachment. Extensive experiments in different online domains demonstrate the superiority of Octet over state-of-the-art methods via both automatic and human evaluations. Notably, Octet enriches an online catalog taxonomy in production to 2 times larger in the open-world evaluation., Comment: KDD 2020

A scalable technique for making octet microlattice topology mechanical metamaterials with a cell size of 1 mm or less from thin stainless steel sheets is described. The microfabrication process used a perforation operation to form planar truss sheets by the periodic removal of rectangular shaped material. A simultaneous perforation and corrugation operation was also used to create a single layer of trusses with a pyramidal topology. A 3D lattice was then assembled by alternatively stacking the pyramidal and planar truss sheets, taking care to align their nodes to form the octet lattice truss topology. A vacuum brazing method was used to metallurgically bond the assembly. The compressive properties of the microlattices are shown to be comparable to those of much larger cell-size structures of similar material and topology. An assessment of geometric imperfection sensitivity indicates where further mechanical property improvements could be realized by improving the precision of both the perforation and assembly process. Keywords: Octet lattice, Microfabrication, Mechanical metamaterials, Mechanical properties

ConspectusUnderstanding special stability of numerous ligand-protected gold nanoclusters has always been an active area of research. In the past few decades, several theoretical models, including the polyhedral skeletal electron pair theory (PSEPT), superatom complex (SAC), and superatom network (SAN), among others, have been developed for better understanding the stabilities and structures of selected ligand-protected gold nanoclusters. This Account overviews the recently proposed grand unified model (GUM) to offer some new insights into the structures and growth mechanism of nearly all crystallized and predicted ligand-protected gold nanoclusters.The main conceptual advancement of the GUM is identification of the duet and octet rules on the basis of the “big data” of 70+ reported ligand-protected gold nanoclusters. According to the two empirical rules, the cores of the gold nanoclusters can be regarded as being composed of two kinds of elementary blocks (namely, triangle Au3 and tetrahedron Au4), each h...

Simple relations connecting the strange quark mass to the splittings of the light hyperon masses were obtained on the basis of the phenomenological quark model compatible with the present-day theory of strong interactions, i.e. with quantum chromodynamics (QCD). Strange quark mass ms = 89.5 ±19.5 MeV, calculated in the proposed approach, is in good agreement with the modern evaluations and calculations of this quantity, mainly obtained by the lattice QCD methods.

As technology advance in 3D printing, octet lattice materials can be made with a wide range of strut aspect ratios. It is essential to develop a satisfying theoretical model for large aspect ratio ranges. In this paper, an analytical model considering material overlapping effect in strut joint, bend and shear has been derived to predict the effect compressive stiffness and strength of the octet lattice materials with cylindrical struts. The models have been validated by FE simulations and experiments. These results demonstrate that the relative compressive stiffness and strength not only depend on the relative density, but also relate to the effect of strut joint, bend and shear. The material overlapping effect in strut joint and the coupling effect between the shearing force and the bending moment will raise the relative compressive stiffness and strength.

The zero-field splitting (ZFS) of the ground state octet in aqueous Eu(II) and Gd(III) solutions was investigated through multi- configurational quantum chemical calculations and ab initio molecular dynamics (AIMD) simulations. Investigation of the ZFS of the lanthanide ions is essential to understand the electron spin dynamics and nuclear spin relaxation around paramagnetic ions and consequently the mechanisms underlying applications like magnetic resonance imaging. We found by comparing clusters at identical geometries but different metallic centres that there is not a simple relationship for their ZFS, in spite of the complexes being isoelectronic - each containing 7 unpaired f electrons. Through sampling it was established that inclusion of the first hydration shell has a dominant (over 90 %) influence on the ZFS. Extended sampling of aqueous Gd(III) showed that the 2 nd order spin Hamiltonian formalism is valid and that the rhombic ZFS component is decisive.

In this paper, an energy coefficient method is presented to predict the nonlinear constitutive relations of stretching dominated lattice materials. The proposed method adopts a process based on boundary coefficient and energy calculation to obtain the effective elastic stiffness of lattice truss materials. Furthermore, the Ramberg–Osgood relationship and the geometrical coefficient is introduced to establish the nonlinear relationship between macro-stress and macro-strain. The method is used to determine the stiffness matrix of the pyramid lattice material and the nonlinear constitutive relationships of the octet lattice material and the 3D Kagome core sandwich panels under uniaxial compression and pure shear, respectively. The obtained results agree well with the related experimental results. This agreement validates the energy coefficient method.

In this work, masses of octet baryons are evaluated in the framework of the perturbative chiral quark model (PCQM) with considering both the ground and excited states in the quark propagator, in which a Cornell-like potential is first constructed by letting the predetermined ground state quark wavefunction satisfy Dirac equation, and the excited quark states are derived by resolving Dirac equation with the extracted PCQM potential numerically employing Generalized Eigenvalue & Eigenstate Problem method. The results on the octet baryon masses are found in good agreement with the experimental data, and the study reveals that the contributions of the excited quark states are considerably influential in the octet baryon masses as expected.

Lattice sandwich beams are often subjected to vibrations when they are used. The aim of this study was to explore the vibration characteristics of the octet-truss lattice core sandwich beam by translating discrete octet-truss core to the continuous homogenization material. The natural frequencies of which are obtained by theoretical calculation and numerical simulation. The theoretical solutions are in good agreement with the numerical results. It demonstrates that the theoretical approach is effective to compute the natural frequency. Furthermore, the influences of truss member radius and thin sheets ply on the natural frequencies are also discussed. The outcomes indicate that the octet-truss lattice core sandwich beam’s natural frequencies are controlled via selecting the appropriate truss member radius and the face sheets thickness.

Structure scouting and design optimization for superior mechanical performance through inverse machine learning is an emerging area of interest. Inverse machine learning can be a substantial approach in structural design to explore complex and massive numbers of geometrical patterns within short periods of time. Here, an inverse design framework using generative adversarial networks (GANs) is proposed to explore and optimize structural designs such as lightweight lattice unit cells. Lightweight lattice structures are widely accepted to have excellent mechanical properties and have found applications in various engineering structures. Using the proposed framework, different lattice unit cells that are 40–120% better in load carrying capacity than octet unit cell are discovered. These new lattice unit cells are analyzed numerically and validated experimentally by testing 3D printed lattice unit cells and lattice cored sandwiches. The proposed inverse design framework can be applied to the design and optimization of other types of load bearing structures.