Search

We present a study of ω(782) and φ (1020) mesons mixing in the framework of the chiral Nambu–Jona-Lasinio model. The decay φ → π0γ is considered as a basic process to determine mixing angle. The width of the decay φ → 3π and the cross-section of the process e+e− → π0φ are calculated in the satisfactory agreement with experimental data. A predictions for semileptonic decays φ → π0[e+e−, μ+μ−] are given. [ABSTRACT FROM AUTHOR]

In this paper we report a calculation of branching ratios for nonleptonic decays of Bc meson in the framework of the covariant confined quark model. We compared the obtained results with available experimental data and other theoretical approaches. [ABSTRACT FROM AUTHOR]

Photoproduction of the ω meson on the proton has been experimentally studied near the threshold. The total cross sections are determined at incident energies ranging from 1.09 to 1.15 GeV. The 1/2 and 3/2 spin-averaged scattering length aωp and effective range rωp between the ω meson and proton are estimated from the shape of the total cross section as a function of the incident photon energy: aωp=(−0.97±0.16)+ i (0.07±0.15) fm and rωp=(+2.78±0.61)+ i (−0.01±0.48) fm, which suggests a repulsive force. The real and imaginary parts for aωp and rωp are determined separately for the first time. The details of the analysis and discussions are described in Ref. [1]. [ABSTRACT FROM AUTHOR]

In this article, we review our study of the K−pp, which is a prototype system of kaonic nuclei, with a fully coupled-channel complex scaling method (Full ccCSM). In the present study, i) the K−pp is treated as a resonant state of a K¯NN-πΣN-πΛN coupled-channel system, ii) a chiral SU(3)-based potential as well as a phenomenological potential is examined as a K¯N-πY potential, and iii) property of the K−pp is investigated by analyzing the wave function obtained with the Full ccCSM calculation. It is noted that the energy dependence involved in a chiral SU(3)-based potential is taken into account by considering the self-consistency for the meson-baryon energy. As a result, we have successfully found a resonant pole corresponding to the K−pp on the complex energy plane, and compared it with the latest experimental result reported by J-PARC E15 group. Furthermore, we have considered an energy-fixed case of a chiral SU(3) potential and also the effect of kinematics of mesons by examining the semi-relativistic calculation. [ABSTRACT FROM AUTHOR]

The "Physics Beyond Colliders (PBC)" study explores fundamental physics opportunities at the CERN accelerator complex complementary to collider experiments. Three new collaborations aim to exploit the M2 beamline in the North Area with existing high-intensity muon and hadron beams, but also aspire to go beyond the current M2 capabilities with a RF-separated, high-intensity hadron beam, under study. The AMBER/COMPASS++ collaboration proposes an ambitious program with a measurement of the proton radius with muon beams, as well as QCD-related studies from pion PDFs / Drell-Yan to cross section measurements for dark sector searches. Assuming feasibility of the RF-separated beam, the spectrum of strange mesons would enter a high precision era while kaon PDFs as well as nucleon TMDs would be accessible via Drell-Yan reactions. The NA64µ collaboration proposes to search for dark sector mediators such as a dark scalar A′ or a hypothetical Zµ using the M2 muon beam and complementing their on-going A′ searches with electron beams. The MuonE collaboration intends to assess the hadronic component of the vacuum polarization via elastic µ − e scattering, the dominant uncertainty in the determination of gµ − 2. An overview of the three new experimental programs will be presented together with implications for the M2 beamline and the experimental area EHN2, based on the studies of the PBC "Conventional Beams" Working Group. [ABSTRACT FROM AUTHOR]

We present measurements of the photon beam asymmetry Σ for the reaction γp → K+Σ0(1193) using the GlueX experiment in Jefferson Lab's Hall D. Data were collected using a linearly polarized photon beam with energy range 8.2-8.8 GeV incident on a liquid hydrogen target. Asymmetries are measured as functions of Mandelstam variables −t and −u. These are the first fully exclusive measurements of the photon beam asymmetry Σ in this reaction at high energies with detection of all final state particles. In the t-channel, results show that the reaction is dominated by the natural-parity exchange of presumably the K*(892) meson, as predicted by theoretical models. Results obtained for the u-channel are consistent with an intermediate baryon exchange mechanism predicted by theoretical models. [ABSTRACT FROM AUTHOR]

Although the ω meson is one of the best established hadrons, its fundamental properties such as the interaction with the nucleon is not known yet due to the difficulties in realizing scattering experiments. Recently, we have performed high-precision photoproduction experiment of the ω meson from the proton near the threshold. The total cross sections are determined at incident energies ranging from 1.08 to 1.15 GeV. The 1/2 and 3/2 spin-averaged scattering length aωN and effective range rωN between the ω meson and nucleon are extracted from the excitation function of the total cross section using a model with the final-state ωN interaction based on the Lippmann-Schwinger equation. The obtained values are a ω p = (− 0.97 − 0.16 + 0.16 ) + i ( 0.07 − 0.14 + 0.15 ) fm and r ω p = (+ 2.78 − 0.54 + 0.68 ) + i (− 0.01 − 0.50 + 0.46 ) fm, suggesting a strong repulsion force. [ABSTRACT FROM AUTHOR]

The GlueX experiment is a photoproduction experiment located at Thomas Jefferson National Lab in Newport News, Virginia. GlueX is capable of making beam asymmetry (Σ) measurements using a tagged, linearly-polarized 9 GeV photon beam incident on a hydrogen target. Measurements of the beam asymmetry for the exclusive reactions γp → π0p, γp → ηp and γp → η′p will provide insight into the meson production mechanisms. GlueX measurements are the first beam asymmetry results for the η and η′ in this energy range and are expected to further constrain Regge theory models for photoproduced pseudoscalar mesons. This talk will present preliminary results of the photon beam asymmetries as a function of the Mandelstam variable, t, for multiple η decay modes and the η′ → π+π−η decay mode. [ABSTRACT FROM AUTHOR]

Lattice QCD allows us to probe the low-lying hadron spectrum in finite-volume using a basis of single- and multihadron interpolating operators. Here we examine the effect of including tetraquark operators on the spectrum in the scalar meson sectors containing the K 0 * (700) (κ) and the a0(980) in Nf = 2+1 QCD, with mπ ≈ 230 MeV. Preliminary results of additional finite-volume states found using tetraquark operators are shown, and possible implications of these states are discussed. [ABSTRACT FROM AUTHOR]

The formalism devoted to the production of two pseudoscalar mesons with a linearly polarized photon beam has been detailed and illustrated in arXiv:1906.04841. This document reports the necessary formulas, without proof, to perform an analysis of the angular distribution of two mesons photoproduction. The relations to extract moments of the angular distribution are provided, as well as the relations between the moments and the partial waves for a system involving S-, P- and D-waves. The expressions of the integrated beam asymmetry and the beam asymmetry along the y axis in term of moments are mentioned. [ABSTRACT FROM AUTHOR]

The GlueX facility, featuring a linearly polarized 9 GeV real photon beam delivered to a large-acceptance detector system, has recently completed its first phase of running, and analysis efforts of this dataset are well underway. It has been suggested that at GlueX energies, quark systems beyond the three quark and quark-antiquark systems of baryons and mesons, such as hybrid mesons, tetraquarks and glueballs, should exist, and studies of these systems could shed new light on how quarks combine under the strong force, particularly the role played by gluons. GlueX data encompasses final states at energies where photoproduction of light scalar mesons, such as a0(980) and f0(980), can provide discriminatory evidence between various models, manifested in experimental observables such as the cross section and beam asymmetry, however many of these analyses comprise multi-particle final states, which can arise from numerous intermediate resonances formed via different production mechanisms. The work presented showcases efforts to measure the beam asymmetry of the reaction γp → pηπ, with a particular interest in future studies of the a0(980) meson, and discusses the application of longitudinal phase space plots, originally introduced by van Hove fifty years ago, as a means of optimizing event selection. This technique has found traction in several multi-particle final state analyses in GlueX, and provides an effective additional means of separately visualising meson and baryon production events with the same final state. [ABSTRACT FROM AUTHOR]

The GlueX experiment at Jefferson Lab aims to study the light meson spectrum with an emphasis on the search for hybrid mesons. To this end, a linearly-polarized 9 GeV photon beam impinges on a hydrogen target contained within a detector with near-complete neutral- and charged-particle coverage. In 2018, the experiment completed its first phase of data taking in its design configuration and the quantity of analyzed data already exceed that of previous experiments for polarized photoproduction in this energy regime by orders of magnitude. Polarization observables such as spin-density matrix elements provide valuable input for the theoretical description of the production mechanism, which will be essential for the interpretation of possible exotic-meson signals. We present results for the photoproduction of vector mesons, focusing on the unprecedented statistical precision of the spin-density matrix elements for the ρ(770) meson. [ABSTRACT FROM AUTHOR]

The study of the spectrum and structure of excited nucleon states employing the electroproduction of exclusive reactions is an important avenue for exploring the nature of the non-perturbative strong interaction. The CLAS detector in Hall B has provided the dominant part of the available world data on most relevant meson electroproduction channels off the nucleon in the resonance region for Q2 up to 5 GeV2. Analyses of CLAS data for the exclusive channels πN, ηN, and π+π−p on a proton target have provided the only results available on the Q2 evolution of the electro-excitation amplitudes for the transitions from the initial photon-proton to the final N* states in the mass range up to W =1.8 GeV. These electrocouplings allow for exploration of the internal structure of the produced excited nucleon states. This work has made it clear that consistent results from independent analyses of several exclusive channels with different resonance hadronic decay parameters and non-resonant backgrounds but the same N* electro-excitation amplitudes, is essential to have confidence in the extracted results. Starting in early 2018, a program to study the spectrum and structure of N* states in various exclusive electroproduction channels using the new CLAS12 spectrometer commenced. These studies will probe the structure of N* states in the mass range up to W =3 GeV and for Q2 as low as 0.05 GeV2 and as high as 10-12 GeV2, thus providing a means to access N* structure information spanning a broad range of distance scales. Quasi-real photoproduction studies are also planned to search for additional N* states, the so-called hybrid baryons, for which the glue serves as an active structural component. In this talk the N* programs from both CLAS and CLAS12 will be reviewed. [ABSTRACT FROM AUTHOR]

Recent developments in studying the φ meson in nuclear matter are summarized and reviewed from a theoretical point of view. Special emphasis is laid on the most recent results dealing with the momentum dependence of the φ meson properties in medium and a first attempt at simulating the pA reactions employed in experimental studies of the φ meson in nuclear matter, making use of a transport model approach. [ABSTRACT FROM AUTHOR]

The search for hybrid mesons and the detailed study of their spectrum is the primary goal of the GlueX Experiment in Hall D at Jefferson Lab. The identification and study of hybrid mesons promises to provide unique insight into gluonic degrees of freedom in QCD and the nature of confinement. The experiment combines an intense photon beam with linear polarization peaking around 9 GeV incident on a liquid hydrogen target with a nearly hermetic spectrometer, enabling the comprehensive study of charged and neutral particle final states. The first phase of the experiment has recently concluded, yielding a photoproduction data set of unprecedented size and quality. We report on the status of the analysis of this data, including measurements of polarization observables, progress in spectroscopic measurements of light mesons, and the measurement of the photoproduction of J/ψ near threshold, which is providing critical insight into the nature of the LHCb closed-charm pentaquark candidates. [ABSTRACT FROM AUTHOR]

I overview our recent activity with the Argonne-Osaka dynamical coupled-channels (DCC) approach that provides a unified description of various electroweak meson productions on single nucleon and nucleus. First I discuss the DCC model of a single nucleon. The DCC model has been developed through a comprehensive analysis of πN, γN → πN, ηN, KΛ, KΣ reaction data. The model has been further extended to finite Q2 region by analyzing pion electroproduction data, and to neutrino-induced reactions using the PCAC relation. Next I discuss applications of the DCC model to electroweak meson productions on the deuteron. We consider impulse mechanism supplemented by final state interactions (FSI) due to NN and meson-nucleon rescatterings. Using this model, I discuss FSI corrections needed to extract γ-neutron reaction observables from γd → πNN, and a novel method to extract ηN scattering length from γd → ηpn. I also discuss FSI corrections on the existing neutrino-nucleon pion production data that had been extracted from neutrino-deuteron data. [ABSTRACT FROM AUTHOR]

K−p interaction is modeled as one-hadron-exchange potential using relativistic kinematic, which is inspired by the success of the Bonn one-boson-exchange potential model for nucleon-nucleon (NN) interaction. The hadrons being exchanged are a scalar meson σ; vector mesons ω and ρ; hyperons Λ and Σ; and a 1/2+ resonance Λ∗(1600). We determine the parameters of the potentials by means of fitting processes to experimental data of K−p differential cross section for kaon laboratory kinetice energy of about 48 MeV to 580 MeV. The differential cross sections are calculated using a three-dimensional (3D) technique without partial-wave expansion. This model gives χ²/N=9.9914 and able to reproduce data quite well above 200 MeV. The contribution of Λ∗(1600)-resonance shows to be small compared with the others. [ABSTRACT FROM AUTHOR]

Among the available meson production processes kaon electroproduction belongs to the process that is yet less understood and analyzed. The existence of electromagnetic form factors makes it difficult to construct a perfect model. In this work, we use multipole approach to study the electromagnetic form factors of hadrons and the resonance contribution in the KΛ electroproduction process. To this end, we construct an isobar model from a multipole approach and extend it to the electroproduction region by including electromagnetic form factors. The result shows a good agreement with the presently available experimental data. [ABSTRACT FROM AUTHOR]

η-meson photoproduction on the nucleon γ + N → η + N was investigated by using the effective Lagrangian approach at the tree level. We consider the leading contributions to the amplitude, which are Born term, vector-meson term, and resonance term. The resonances listing up to spin-5/2 (20 resonances) are taken from Particle Data Group which is updated at January 19th, 2019. The unknown values of the model parameter are extracted from fitting to around 1082 experiment data. We also calculate the differential cross section to compare the model predictions with the experiment data. And lastly, we analyze the graphics quantitatively at several cosθ. [ABSTRACT FROM AUTHOR]

The ground state (1S ) masses of the pseudoscalar (JP = 0−) and the vector (JP = 1−) D mesons are computed in the phenomenological framework of quark-antiquark potential (color-Coulomb plus screening confinement) model with a Gaussian wave function. The relativistic first-order correction O ( 1/m ) is incorporate to the potential energy term and the relativistic corrections to the kinetic energy term is included by expanding it up to O(p10) power. Our results are compared with the experimental measurements as well as the lattice and other theoretical predictions. [ABSTRACT FROM AUTHOR]

The thermal properties of the light tensor ρ2 meson with quantum numbers JPC = 2−− are studied at finite temperature. In our calculations, two-point Thermal QCD sum rules approach is employed including contributions up to operator dimension-5 of quark, gluon, and quark-gluon mix condensates. We present thermal effects on the main hadronic properties namely, mass and decay constant of the considered resonance in SU(3) nonet, which provides more knowledge about axial-tensor family for experiments. The non-perturbative treatments of the light quark dynamics results in mass spectra at zero temperature agree with available experimental data and thermal behavior of meson parameters can be tested in future experiments. [ABSTRACT FROM AUTHOR]

η-meson photoproduction on the proton was studied by using the effective Lagrangian approach at the tree-level in energy range from treshold up to 1.87 GeV. Besides the Born and vector-meson terms, S11 (1535), S11 (1650) and D13 (1520), were included in the calculation of the transition amplitudes. The role of the D13 resonance was investigated according to the simple and complete formulation of the spin-3/2 propagator. The parameters were extracted from fitting to the experimental data consisting of differential cross sections from the Crystall Ball Collaboration at MAMI. [ABSTRACT FROM AUTHOR]

In the framework of the anomaly sum rules approach, based on the dispersion representation of the axial anomaly and the global quark-hadron duality hypothesis, expressions of electromagnetic Transition Form Factors(TFF) for the pseudoscalar mesons are derived. The obtained solutions take into account the mixing between η − η′ and the contribution of the non-abelian matrix element ⟨0|GG̃|γγ*⟩. Using experimental data for η, η′ TFFs, we establish properties of ⟨0||GG̃||γγ*⟩ for the case of γ*. [ABSTRACT FROM AUTHOR]

This contribution, in the field of hadron physics, highlights two aspects of the structure of the nucleon, in its ground and excited states: the sensitivity of the tensor analyzing power for the process d→+p→d+X to the longitudinal form factor of an excited state, the Roper resonance, calculated in the frame of the algebraic collective model for the electroexcitation of nucleon resonances; - the electromagnetic proton form factor, given by a model based on vector meson dominance. This model predicted the decrease of the electric to magnetic proton form factor ratio, well before precise data appeared and it contains the necessary analytical properties to be extended to the annihilation region, where theory and experiment know important developments today. [ABSTRACT FROM AUTHOR]

In this contribution, we discuss the possible importance of continuum-coupling (or threshold) effects in heavy quarkonium spectroscopy. Our calculations are carried out in a coupled-channel model, where meson-meson higher Fock (or molecular-type) components are introduced in QQ̄, bare meson wave functions by means of a pair-creation mechanism. After providing a quick resume of the main characteristics of the coupled-channel model, we briefly discuss its application to the calculation of the masses of heavy quarkonium-like χc(2P) and χb(3P) states with threshold corrections. We show that the introduction of pair-creation effects in the Quark Model (QM) formalism makes it possible to explain the deviations of χc(2P) states’ masses from the experimental data, without affecting the good QM description of the properties of χb(3P) states. [ABSTRACT FROM AUTHOR]

Mass formulas for vector mesons based on group theoretical descriptions and supersymmetry suggested by QCD and based on quark-diquark symmetry is exploited. [ABSTRACT FROM AUTHOR]

Evidence for a narrow Λ* resonance at a mass of about 1665 MeV (just above the combined mass of the Λ ground state plus the η meson) has been seen in the M(pK−) mass of the Dalitz plot for Λc → pK−π+ decay at the Belle experiment. Additional evidence for this resonance is found in the partial-wave analysis (PWA) of data on K− p reactions done independently by several groups, driven by angular distributions of the K− p → Λη reaction by the Crystal Ball collaboration. If a narrow Λ* resonance exists at this mass, then the conventional quark model cannot explain it, and a possible explanation is that it is a crypto-exotic baryon with a dominant meson-baryon component to its wave function. Therefore we have proposed a definitive experiment for K− p → Λη, using the newly built hypTPC detector to establish the existence of the proposed narrow Λ(1665) and determine its spin and parity in just two weeks of beamtime at J-PARC (E72). [ABSTRACT FROM AUTHOR]

Motivated by the recent precise SIDDHARTA measurement of the energy shift and width of kaonic hydrogen, we have revisited the theoretical study of the meson-baryon interaction in the S = −1 sector, employing a chiral SU(3) lagrangian up to next-to-leading order (NLO) and implementing unitarization in coupled channels. The parameters of the model have been fitted to a large set of experimental data, paying attention to processes that are especially sensitive to the NLO terms, such as the K−p → K+Ξ−, K0 Ξ0 reactions. Explicit resonant terms have been included to explore their effects on the stability of the low-energy constants and the data description. We have also studied the role of new single isospin reactions and have found them to provide more homogeneous and reliable NLO parameters. We conclude that additional isospin filtering processes, like the K0Lp → K+Ξ−, K0Ξ0 reaction that could be measured at the proposed secondary K0L beam at Jlab, would put valuable constraints on the chiral models describing the S = −1 meson-baryon interaction. [ABSTRACT FROM AUTHOR]

The goal of these proceedings is to review recent progress in studies of mesons with (hidden or open) charm or strangeness in nuclear matter. Particular focus is laid on the ϕ and D mesons which are particularly interesting in view of studying the effect of the partial restoration of chiral symmetry at finite density. Both effective theory approaches based on hadronic degrees of freedom and QCD methods involving quarks and gluons will be discussed. [ABSTRACT FROM AUTHOR]

We present an effective field theory (EFT) at leading order to describe light single-Λ hypernuclei. Owing to the weak Λ binding and to the ΛN short interaction range, meson exchange forces are approximated by contact interactions within a pionless EFT (...EFT) where the only degrees of freedom are baryons. At leading order, the Λ-nuclear interaction contains two 2-body (singlet and triplet) and three 3-body interaction terms, a total of 5 terms associated with 5 coupling strengths or low energy constants (LECs). We adopt the 2-body LECs from hyperon-nucleon scattering data and interaction models that constrain the ΛN scattering lengths, while the 3-body LECs are adjusted using both 3-body and 4-body hypernuclear binding energies. To calculate the binding energies for A-body systems with A>2, we expand the wavefunctions using a correlated Gaussian basis. The stochastic variational method is employed to select the non-linear parameters. The resulting ...EFT is then applied to calculate the Λ separation energy in 5ΛHe, where the adjusted 3-body interactions largely resolve the known overbinding problem of 5ΛHe. [ABSTRACT FROM AUTHOR]

Nuclear systems with antikaons, so-called kaonic nuclei, have been a longstanding issue in strange nuclear physics and hadron physics, because they might have exotic nature; In particular, they could be a doorway to the dense matter due to the strong attraction between antikaon and nucleon. Among kaonic nuclei, the three-body system composed of two protons and a single K− meson, K− pp, is the most essential. In this article, we will report on the recent situation of K− pp studies in both theoretical and experimental sides. Afterwards, we will explain our latest study of the K− pp with a fully coupled-channel complex scaling method (Full ccCSM) using a chiral SU(3)-based K̄N(-πY) potential. In Full ccCSM, the K− pp is completely treated as a resonant state of a K̄NN-πΣN-πΛN coupled-channel system. The energy dependence involved in the chiral potential is handled with a self-consistent calculation in which two extreme ansatzes are examined: field picture and particle picture. With our chiral SU(3)-based potential constrained by the precise data of kaonic hydrogen atom (SIDDHARTA experiment), the K− pp resonance is obtained as a shallowly bound state measured from the K̄NN threshold with a narrow width, if the field picture is employed in the calculation: the binding energy is 14 – 28 MeV and the half value of the mesonic decay width is 8 – 15 MeV. On the other hand, if the particle picture is employed, it is found that the binding energy could be as large as about 50 MeV, even though such a chiral potential is used. Based on these results of Full ccCSM calculation, we have discussed on the possibility for kaonic nuclei to form a dense matter and on the latest experimental result reported by J-PARC E15 collaboration. [ABSTRACT FROM AUTHOR]

The Nambu–Jona-Lasinio quark model is a successful tool for investigating hadron physics and the spontaneous chiralsymmetry-breaking mechanism. In this paper its generalization for SU(2) isospin group is presented. It includes all possible quantum numbers of spin-1 mesons. Simultaneous consideration of all these states leads to interesting predictions like novel mass formula and relations among meson coupling constants. [ABSTRACT FROM AUTHOR]

The status of the hidden beauty state Yb is not clear up to now. The deviations from the expected behavior can provide a clue to consider it as an exotic meson candidate. Assuming the Yb resonance as a tetraquark, we estimated its mass and pole residue, both at vacuum and T ≠ 0 temperatures by calculating hot-medium contributions to hadronic parameters in the framework of Thermal QCD sum rules. Our results depict that the mass and pole residue values decrease dramatically at the vicinity of a critical temperature. Comparison of our results with the recent experimental data and theoretical results might be helpful in understanding the internal structure of bottomonium-like Yb state. [ABSTRACT FROM AUTHOR]

The simplest form of the Hyperfine Interaction (HFI) of quarks is a color-spin interaction, sometimes called Fermi-Breit (FB) HFI. For conventional hadrons, this HFI for quark-antiquark (qq̄) pairs is twice as strong as the same HFI for quark-quark (qq or q̄q̄) pairs, but this difference is absorbed into the different HFI constants for mesons and baryons, which are free parameters of the fits. For tetraquarks, however, qq̄ HFI is only half as strong as the qq/q̄q̄ HFI and both kinds of pairs coexist within the same state. Hence it is worth investigating a model with different fit constants for qq̄ and qq/q̄q̄ pairs. We have investigated 3 models of spin-color HFI for light scalar tetraquarks: 2 models with single constants for both kinds of pairs and one model with different fit constants. The light scalar nonet is chosen because of a lack of other experimentally observed multiplets interpretable as pure exotic states. Since even the nonet contains only 3 particles with distinct masses (i. e. 3 fit points), the constituent quark masses had to be taken from conventional hadron fits obtained in our previous work. The two-constant model did not prove to be a viable alternative to the one-constant models. [ABSTRACT FROM AUTHOR]

We present a detailed study of charged-current quasielastic (anti)neutrino scattering cross sections on a 12C target obtained using a spectral function S (p, ε) that gives a scaling function in accordance with the electron scattering data. The spectral function accounts for the nucleon-nucleon (NN) correlations, it has a realistic energy dependence and natural orbitals (NO’s) from the Jastrow correlation method are used in its construction. The results are compared with those when NN correlations are not included, namely harmonic-oscillator single-particle wave functions are used instead of NO’s. A comparison of the results with recent experiments, as well as to results from the superscaling approach is done. The contribution of two-particle two-hole meson-exchange currents on neutrino–nucleus interactions is also considered within a fully relativistic Fermi gas. The results show a good agreement with the experimental data over the whole range of neutrino energies. [ABSTRACT FROM AUTHOR]

Coherent photoproduction of π0-meson from the deuteron near π0-production threshold is investigated with special emphasize on single polarization observables. We report numerical results for the linear photon asymmetry Σ and tensor deuteron spin asymmetries T2M (M=0,1,2). The sensitivity of obtained results to the D-state contribution in the deuteron wave function of realistic NN potentials is studied. It is shown that the influence of D-state contribution on the predicted spin observables is sizable, and it provides important constraints for the extraction of the elementary neutron amplitude. Compared with the experimental data from TAPS collaboration for differential cross section, we obtain a satisfactory agreement. [ABSTRACT FROM AUTHOR]

We use the hydrogen like trial wave function for computation of the mass spectra and decay properties of charmonia within the framework of phenomenological quark anti-quark Coulomb plus power potential with varying potential index from 0.5 to 2.0. The spin-spin hyperfine interaction is considered to incorporate splitting of the ground and radially excited states energy levels, further spin-orbit and tensor interactions are employed to calculate the masses of orbitally excited states. We construct the Regge trajectories from the mass spectra in (J, M2) and (nr, M2) planes. We also compute γγ decay width of P wave states of cc̄. [ABSTRACT FROM AUTHOR]

We address the question as to whether data for J/ψ mesons produced exclusively in the forward direction at the LHC can be used in global parton analyses (based on collinear factorization) to pin down the low-x gluon PDF. We show that it may be possible to overcome the problems that (i) the process is described by a skewed or Generalized Parton Distribution (GPD), (ii) it is very sensitive to the choice of factorization scale and (iii) there is bad LO, NLO,... perturbative stability to the predictions. However, we start by briefly explaining how the alternative kT-factorization approach has been used to describe the process. [ABSTRACT FROM AUTHOR]

We compute the rate for diffractive f electro-production using the Color Glass Condensate dipole model. The model parameters are obtained from fits to the most recent combined HERA data on inclusive deep inelastic scattering. As for the φ meson, we use an AdS/QCD holographic light front wavefunction. Our predictions are compared to the available data collected at the HERA collider. [ABSTRACT FROM AUTHOR]

From a brief recapitulation of the foundational works of Marius Sophus Lie and Herrmann Günther Grassmann, and including missing African links, a rhapsodic survey is made of the straight line of extension and existence that runs as the very fibre of generation and creation throughout Nature's all utterances, which must therefore ultimately be the web of Reality itself of which the Arts and Sciences are interpreters on equal explorer terms. Assuming their direct approach, the straight line and its archaic and algebraic and artistic bearings and convolutions have been followed towards their inner reaches, which earlier resulted in a retrieval of the baryon and meson elementary particles and now equally straightforward the electron geodesics and the organic build of the periodic system of the elements. [ABSTRACT FROM AUTHOR]

We give a review on the SIMP paradigm and discuss a consistent model for SIMP dark mesons in the context of a dark QCD with flavor symmetry. The Z0-portal interaction is introduced being compatible with stable dark mesons and is responsible for making the SIMP dark mesons remain in kinetic equilibrium with the SM during the freeze-out process. The SIMP parameter space of the Z0 gauge boson can be probed by future collider and direct detection experiments. [ABSTRACT FROM AUTHOR]