Search

The conventional nuclear forces at low energies are described by NN-potentials that arise within the framework of the classical mesonic theory as a consequence of the interchange of mesons. Under the situation the mentioned NN-potentials depend on the mesonic masses as parameters. From the point of view of quantum chromodynamics (QCD), however, the mesons and nucleons are composed of quark-gluon configurations and are the result of a confinement mechanism, i.e., the quark-gluonic hadronization into mesons (nucleons). Hence the above mesonic masses should be some functions of quark-gluonic degrees of freedom. When using the confinement mechanism proposed earlier by one of the authors in QCD we adduce the sought functions in an explicit form which enables us to conclude that the NN-potentials only correspond to some residual interactions while the latter are the direct result of the quark-gluonic hadronization into mesons when approching two nucleons.

We report the results for charge radii and decay constants of heavy–light D and B mesons in an improved QCD potential model. To enhance the effectiveness of short-range and long-range effect of the potential $$V(r)=-\frac{4 \alpha _\mathrm{s}}{3r}+\mathrm{br}$$ in the perturbative procedure a cutoff parameter $$r^P$$ is introduced as an integration limit. Another cutoff $$r_0$$ is used for the polynomial approximation of the series expansion used in the Dalgarno’s method of perturbation. The results obtained are found to be in agreement with other available data. The limitation of the approach is discussed in the manuscript.

The phenomena of hadron mass generating, strong running coupling and radiative transitions of charmonium excited states have been studied in the framework of a relativistic field model with analytic confinement. A meson mass equation is derived and a specific new behavior of the mass-dependent strong coupling $$\mathop {\bar {\alpha }}\nolimits_s $$ is revealed in the time-like region. A new infrared fixed point $$\mathop {\bar {\alpha }}\nolimits_s (0) = 1.032$$ has been found at origin. Independent and new estimates on the scalar glueball mass, radius and gluon condensate value have been performed. The spectrum of conventional mesons have been calculated by introducing a minimal set of parameters with relative errors less than 1.8 percent compared to the latest data. Accurate estimates of the leptonic decay constants of pseudoscalar and vector mesons have also been performed. Partial decay widths of the dominant radiative transitions of the charmonium orbital excitations have been estimated with reasonable accuracy.

We explore the hypothesis that the unexplained data from LSND and MiniBooNE are evidence for a new, heavy neutrino mass-eigenstate that mixes with the muon-type neutrino and decays into an electron-type neutrino and a new, very light scalar particle. We consider two different decay scenarios, one with Majorana neutrinos, one with Dirac neutrinos; both fit the data equally well. We find a reasonable, albeit not excellent, fit to the data of MiniBooNE and LSND. The decaying-sterile-neutrino hypothesis, however, cleanly evades constraints from disappearance searches and precision measurements of leptonic meson decays, as long as $1~{\rm MeV}\gtrsim m_4\gtrsim 10$~keV. The SBN program at Fermilab should be able to definitively test the decaying-sterile-neutrino hypothesis., This version v2 has been accepted for publication in JHEP. The changes from previous version are: inclusion of the data from KARMEN in the analysis, a new subsection about the sensitivity of SBN to nonzero decay effects, an new appendix describing the details of MiniBooNE analysis, additional references and some other minor changes

In this paper, Schrodinger equation is numerically applied through non-relativistic potential model for deriving Spectrum, radial wave functions at origin, decay constants, lepton and photon decay widths for radial and orbital excited conventional as well as hybrid charmonium mesons. These calculated results are found in agreement with others theoretical results and with the experimental observations., Comment: 12 pages, 10 Tables

Tau-lepton semileptonic decays are described in the Nambu–Jona-Lasinio framework, and the validity of this description is discussed. Tau decays with a neutrino, a vector meson, and a pseudoscalar meson in the final state are considered. The extended version of the NJL model is employed, which makes possible the consideration of the contributions of both the ground and first radially excited meson states.

Spectrum, radii, radial wave functions at origin, decay constants, and momentum widths for radial and orbital excited $$B_{c}$$ mesons are derived within non-relativistic quark model framework through finding numerical solution of the Schrodinger equation by shooting method. Masses of orbitally excited states are derived with a much simpler method that is developed by combining the uncertainty and variational principles. Masses of $$B_{c}$$ mesons are also calculated by using Momentum widths. Besides calculations, theoretical results are compared with the experimental observations which have implications for scalar form factors and leptonic decays of $$B_{c}$$ mesons.

Negative and positive muon irradiation tests of static random access memories (SRAMs) were performed at Muon Science Innovation Channel (MuSIC) of Research Center for Nuclear Physics (RCNP), Osaka University. The muon-induced single event upset (SEU) cross sections for 65-nm bulk SRAMs were measured. The SRAM device was irradiated by the muon beams with average momenta ranging from 37.8 to 41.0 MeV/c at the beam exit. The incident muon fluence was measured using a one-by-one muon detection system with a plastic scintillator by taking advantage of the direct current (dc) muon beam and reliable absolute values of SEU cross sections were obtained. In addition to the measurement of the SEU cross sections, we measured muonic X-rays from the irradiated device to investigate the relation between the measured SEU cross section and the emission rate of muonic X-rays associated with the stopping position of the muons as a function of incident muon momentum. The result suggested that negative muons have a significant effect on SEUs by the emission of secondary light ions via negative muon capture reaction when negative muons stop near sensitive volumes (SVs) in SRAMs.

It is shown that all predictions for the light scalars, based on their four-quark nature, are supported by experiment. The future research program is outlined also., Comment: 10 pages, 14 figures, Invited talk at the International Conference "Problems of Theoretical and Mathematical Physics" dedicated to the 110th anniversary of the birth of the outstanding Russian scientist - mathematician and physicist Nikolai Nikolaevich Bogolyubov, JINR, Dubna, September 11 - 13, 2019. arXiv admin note: text overlap with arXiv:1807.00179

The Large Hadron Collider beauty (LHCb) experiment is one of the four main particle detectors located at the Large Hadron Collider. After the high-luminosity upgrade of the accelerator, the expected radiation dose faced by the LHCb electromagnetic calorimeter will reach peak values of 1 MGy in the centermost part, an amount not tolerable by the currently employed Shashlik technology, which demands a novel radiation hard design. In addition, a time resolution of few tens of picoseconds and a cell lateral size of about 2 cm are planned for track reconstruction purposes by thecollaboration. In this article, the crystal spaghetti design was evaluated, a sampling geometry where scintillating crystal fibers are embedded in the dense absorbing material. The prototype was tested at CERN super proton synchrotron (SPS) with muons and electrons measuring an energy resolution of 3% for electrons at 20 GeV, tilting the prototype by $3^◦$ both horizontally and vertically with respect to the incident beam, and a time resolution of 79 ps. The results presented in this article show the feasibility of the design.

We study the heavy-light mesons within basis light-front quantization. The resulting mass spectra of $D$, $D_s$, $B$, and $B_s$ agree reasonably well with experiments. We also predict states which could be measured in the near future. In the light-front formalism, we calculate the light-front wave functions and additional experimental observables, such as parton distribution functions, distribution amplitudes, and decay constants by means of integrations over light-front wave functions. We also provide ratios of decay constants for selected pseudoscalar meson decays ($D_s$ to $D$ and $B_s$ to $B$) as they may prove to be theoretically more robust and more reliably determined in experiments. We find that our ratios are systematically smaller than existing experiment and other approaches by $5-18\%$., 15 pages, 19 figures, 2 tables

Using the data collected by the CMS experiment at the Large Hadron Collider in collisions of protons with a center-of-mass energy of 8 TeV, excited P-wave states $${\text{B}}_{{{\text{s}}2}}^{ * }{{(5840)}^{0}}$$ and Bs1(5830)0 of the $${\text{B}}_{{\text{s}}}^{0}$$ meson are studied. The decay $${\text{B}}_{{{\text{s}}2}}^{ * }{{(5840)}^{0}} \to {{{\text{B}}}^{0}}{\text{K}}_{{\text{s}}}^{0}$$ is observed for the first time, the first indication of the $${\text{B}}_{{{\text{s1}}}}^{ * }{{(5840)}^{0}} \to {\text{B}}_{{}}^{{ * 0}}{\text{K}}_{{\text{s}}}^{0}$$ decay existence is obtained, the probabilities of these decays with respect to the corresponding decays into B(*)+ $${\text{K}}_{{}}^{ - }$$ are measured. B0 and B+ ground states are reconstructed using $${{{\text{B}}}^{0}} \to {\text{J/}}\psi {{{\text{K}}}^{ + }}{{\pi }^{ - }}$$ and $${{{\text{B}}}^{ + }} \to {\text{J/}}\psi {{{\text{K}}}^{ + }}$$ decays. Masses of P-wave $${\text{B}}_{{\text{s}}}^{0}$$ mesons and the natural width of the $${\text{B}}_{{{\text{s}}2}}^{ * }{{(5840)}^{0}}$$ meson are measured; the mass difference $$M({\text{B}}{{{\text{*}}}^{0}}) - M({\text{B}}{{{\text{*}}}^{ + }})$$ between charged and neutral B* mesons is determined for the first time.

In the framework of the diagrammatic approach, the total cross section of near-threshold π– photoproduction on the deuteron is calculated. Contributions of the diagrams corresponding to the plane wave impulse approximation as well as to NN- and πN-interactions in the final state have been taken into account. We have compared the theoretical predictions with the results of the recent measurements performed at the MAX IV laboratory of the Lund University. There is good agreement with the data at photon energies from 147 to 155 MeV. However, at 158 and 160 MeV, the theoretical predictions significantly overestimate the measured cross sections.

Charged pions1 are the lightest and longest-lived mesons. Mesonic atoms are formed when an orbital electron in an atom is replaced by a negatively charged meson. Laser spectroscopy of these atoms should permit the mass and other properties of the meson to be determined with high precision and could place upper limits on exotic forces involving mesons (as has been done in other experiments on antiprotons2–9). Determining the mass of the π− meson in particular could help to place direct experimental constraints on the mass of the muon antineutrino10–13. However, laser excitations of mesonic atoms have not been previously achieved because of the small number of atoms that can be synthesized and their typically short (less than one picosecond) lifetimes against absorption of the mesons into the nuclei1. Metastable pionic helium (π4He+) is a hypothetical14–16 three-body atom composed of a helium-4 nucleus, an electron and a π− occupying a Rydberg state of large principal (n ≈ 16) and orbital angular momentum (l ≈ n − 1) quantum numbers. The π4He+ atom is predicted to have an anomalously long nanosecond-scale lifetime, which could allow laser spectroscopy to be carried out17. Its atomic structure is unique owing to the absence of hyperfine interactions18,19 between the spin-0 π− and the 4He nucleus. Here we synthesize π4He+ in a superfluid-helium target and excite the transition (n, l) = (17, 16) → (17, 15) of the π−-occupied π4He+ orbital at a near-infrared resonance frequency of 183,760 gigahertz. The laser initiates electromagnetic cascade processes that end with the nucleus absorbing the π− and undergoing fission20,21. The detection of emerging neutron, proton and deuteron fragments signals the laser-induced resonance in the atom, thereby confirming the presence of π4He+. This work enables the use of the experimental techniques of quantum optics to study a meson. Long-lived pionic helium atoms (composed of a helium-4 nucleus, an electron and a negatively charged pion) are synthesized in a superfluid-helium target, as confirmed by laser spectroscopy involving the pion-occupied orbitals.

Two-particle angular correlations is a robust tool that allows to study different physical properties of the system created in the high-energy collisions of both protons and heavy ions. ALICE experiment enable correlation measurements of identified particles for different collision systems, including less common probes, like ϕ mesons, $$D$$ mesons and deuterons. In this document selected ALICE correlation measurements with identified particles are reported.

The magnetic dipole polarizabilities and hyperpolarizabilities of the vector $${{\rho }^{0}}$$ and $${{\rho }^{ \pm }}$$ mesons have been calculated. The new characteristic of NPQCD in the strong magnetic field called tensor polarizability has been introduced, which is related to the tensor polarization of vector mesons. The contribution of the dipole magnetic polarizabilities to the tensor polarization of the vector mesons in the external abelian magnetic field has been explored.

We study phenomenological constraints on a simple $3-3-1$ model with flavor violating Yukawa couplings. Both triplets Higgs couple to leptons and quarks, which generates flavor violating signals in both lepton and quark sectors. We have shown that this model can allow for large Higgs lepton flavor-violating rate decay $h \rightarrow \mu \tau$ and also can be reached to perfect agreements with other experimental constraints such as $\tau \rightarrow \mu \gamma$ and $(g-2)_\mu$. The contributions of flavor-changing neutral current (FCNC) couplings, Higgs-quark-quark couplings, to the mesons mixing are investigated. Br$(h \rightarrow q q^\prime )$ can be enhanced with keeping from the measurements of meson mixing. The branching ratio for $t \rightarrow q h$ can reach up to $10^{-3}$, but it could be as low as $10^{-8}$., Comment: 21 pages, 8 figures

A hydrodynamic approach with a nonequilibrium equation of state is used to describe collisions between heavy ions with medium energies. The double differential cross sections for the production of subthreshold $${{\pi }^{0}}$$ mesons and $${{\pi }^{ + }}$$ mesons during collisions between various nuclei are calculated to develop this approach with the inclusion of nuclear viscosity effects. They are in good agreement with the available experimental data.

We revisit QCD calculations of radiative heavy meson decay form factors by including the subleading power corrections from the twist-two photon distribution amplitude at next-to-leading-order in $\alpha_s$ with the method of the light-cone sum rules (LCSR). The desired hard-collinear factorization formula for the vacuum-to-photon correlation function with the interpolating currents for two heavy mesons is constructed with the operator-product-expansion technique in the presence of evanescent operators. Applying the background field approach, the higher twist corrections from both the two-particle and three-particle photon distribution amplitudes are further computed in the LCSR framework at leading-order in QCD, up to the twist-four accuracy. Combining the leading power "point-like" photon contribution at tree level and the subleading power resolved photon corrections from the newly derived LCSR, we update theory predictions for the nonperturbative couplings describing the electromagnetic decay processes of the heavy mesons $H^{\ast \, \pm} \to H^{\pm} \, \gamma$, $H^{\ast \, 0} \to H^{0} \, \gamma$, $H_s^{\ast \, \pm} \to H_s^{\pm} \, \gamma$ (with $H=D, \, B$). Furthermore, we perform an exploratory comparisons of our sum rule computations of the heavy-meson magnetic couplings with the previous determinations based upon different QCD approaches and phenomenological models., Comment: 39 pages, 4 figures

The interaction of nucleon-nucleon (NN) has certain physical characteristics, indicated by nucleon, and meson degrees of freedom. The main purpose of this work is calculating the ground-state energies of 12H and 24He through the two-body system with the exchange of mesons (π, σ, and ω) that mediated between two nucleons. This paper investigates the NN interaction based on the quasirelativistic decoupled Dirac equation and self-consistent Hartree-Fock formulation. We construct a one-boson exchange potential (OBEP) model, where each nucleon is treated as a Dirac particle and acts as a source of pseudoscalar, scalar, and vector fields. The potential in the present work is analytically derived with two static functions of meson, the single-particle energy-dependent (SPED) and generalized Yukawa (GY) functions; the parameters used in meson functions are just published ones (mass, coupling constant, and cutoff parameters). The theoretical results are compared to other theoretical models and their corresponding experimental data; one can see that the SPED function gives more satisfied agreement than the GY function in the case of the considered nuclei.

We use the QCD sum rules for the three-point correlation functions to compute the strong coupling constants of the meson vertices $J/\psi D_{s}^{*} D_{s}^{*}$. Using the QCD sum rules, we obtain the form factor of the vertex, the coupling constant, and the cut off parameter. Uncertainties are included. The results obtained for the coupling constants are $g_{J/\psi D^{*}_{s} D^{*}_{s}} = 7.47^{+1.04}_{-0.71}.$.

The exotic JPC=1−+resonance π11600 is examined in the framework of the Quark Model with Constituent Gluon (QMCG). We report the possibility of interpreting that resonance as qq¯g meson, with a masse ≃1.65−0.04+0.05 GeV, and a decay width to ρπ≃0.28−0.09+0.14 GeV.

Generalized Chou-Yang model (GCYM) predicts electromagnetic form factors of several hadrons with varying magnitude of strangeness. By using these form factors, the root mean square (RMS) radii of the hadrons such as (π, p, ϕ, Λ, Σ+, Σ−and Ω−)are computed. It is found that there is consistency among the predicted RMS radii of pion and proton by GCYM (and other models) and experimental results. For all hadrons experimental results are not available. Also we find that results of GCYM and from other models are somewhat inconsistent for hadrons other than pion and proton. Though GCYM and other models do not agree for most of the hadrons but they have one similarity that the computed RMS radii seem decreasing with the increase in the strangeness level, separately for mesons as well as for baryons. The experimental results of hadrons other than pion and proton are needed to check the suitability of GCYM and other models as well as in probing the trend of decreasing radii with increase in strangeness content.

Measurements of the branching fractions of the semileptonic decays B → D ( * ) τ ν ¯ τ and B c → J / ψ τ ν ¯ τ systematically exceed the Standard Model predictions, pointing to possible signals of new physics that can violate lepton flavor universality. The unknown origin of new physics realized in these channels can be probed using a general effective Hamiltonian constructed from four-fermion operators and the corresponding Wilson coefficients. Previously, constraints on these Wilson coefficients were obtained mainly from the experimental data for the branching fractions. Meanwhile, polarization observables were only theoretically studied. The situation has changed with more experimental data having become available, particularly those regarding the polarization of the tau and the D * meson. In this study, we discuss the implications of the new data on the overall picture. We then include them in an updated fit of the Wilson coefficients using all hadronic form factors from our covariant constituent quark model. The use of our form factors provides an analysis independent of those in the literature. Several new-physics scenarios are studied with the corresponding theoretical predictions provided, which are useful for future experimental studies. In particular, we find that under the one-dominant-operator assumption, no operator survives at 1 σ . Moreover, the scalar operators O S L and O S R are ruled out at 2 σ if one uses the constraint B ( B c → τ ν τ ) ≤ 10 % , while the more relaxed constraint B ( B c → τ ν τ ) ≤ 30 % still allows these operators at 2 σ , but only minimally. The inclusion of the new data for the D * polarization fraction F L D * reduces the likelihood of the right-handed vector operator O V R and significantly constrains the tensor operator O T L . Specifically, the F L D * alone rules out O T L at 1 σ . Finally, we show that the longitudinal polarization P L τ of the tau in the decays B → D * τ ν ¯ τ and B c → J / ψ τ ν ¯ τ is extremely sensitive to the tensor operator. Within the 2 σ allowed region, the best-fit value T L = 0.04 + i 0.17 predicts P L τ ( D * ) = − 0.33 and P L τ ( J / ψ ) = − 0.34 , which are at about 33% larger than the Standard Model (SM) prediction P L τ ( D * ) = − 0.50 and P L τ ( J / ψ ) = − 0.51 .

The measured branching ratio of the $D$ meson semileptonic decay $D \to \rho e^+ \nu_e$, which is based on the $0.82~{\rm fb^{-1}}$ CLEO data taken at the peak of $\psi(3770)$ resonance, disagrees with the traditional SVZ sum rules analysis by about three times. In the paper, we show that this discrepancy can be eliminated by applying the QCD light-cone sum rules (LCSR) approach to calculate the $D\to \rho$ transition form factors $A_{1,2}(q^2)$ and $V(q^2)$. After extrapolating the LCSR predictions of these TFFs to whole $q^2$-region, we obtain $1/|V_{\rm cd}|^2 \times \Gamma(D \to \rho e \nu_e) =(55.45^{+13.34}_{-9.41})\times 10^{-15}~{\rm GeV}$. Using the CKM matrix element and the $D^0(D^+)$ lifetime from the Particle Data Group, we obtain ${\cal B} (D^0\to \rho^- e^+ \nu_e) = (1.749^{+0.421}_{-0.297}\pm 0.006)\times 10^{-3}$ and ${\cal B} (D^+ \to \rho^0 e^+ \nu_e) = (2.217^{+0.534}_{-0.376}\pm 0.015)\times 10^{-3}$, which agree with the CLEO measurements within errors. We also calculate the branching ratios of the two $D$ meson radiative processes and obtain ${\cal B}(D^0\to \rho^0 \gamma)= (1.744^{+0.598}_{-0.704})\times 10^{-5}$ and ${\cal B}(D^+ \to \rho^+ \gamma) = (5.034^{+0.939}_{-0.958})\times 10^{-5}$, which also agree with the Belle measurements within errors. Thus we think the LCSR approach is applicable for dealing with the $D$ meson decays., Comment: 12 pages, 7 figures, version to be published in EPJC

In this work, we present a thorough analysis of $\eta_c(1S,2S)$ quarkonia hadroproduction in $k_\perp$-factorisation in the framework of the light-front potential approach for the quarkonium wave function. The off-shell matrix elements for the $g^* g^* \eta_c(1S,2S)$ vertices are derived. We discuss the importance of taking into account the gluon virtualities. %We discuss the role of relativistic corrections, the Melosh spin-rotation and theoretical uncertainties by comparing our results with the standard NRQCD approach. We present the transverse momentum distributions of $\eta_c$ for several models of the unintegrated gluon distributions. Our calculations are performed for four distinct parameterisations for the $c\bar c$ interaction potential consistent with the meson spectra. We compare our results for $\eta_c(1S)$ to measurements by the LHCb collaboration and present predictions for $\eta_c(2S)$ production., Comment: 17 pages, 12 figures

We study quark flavor violating interactions mediated by the Higgs boson $h$. We consider observables involving a third generation quark, of both the up and the down quark sectors, like $h\rightarrow bs$ and $t\rightarrow ch$. Using an effective field theory approach we systematically list all the possible tree-level ultraviolet completions, which comprise models with vector-like quarks and/or extra scalars. We provide upper bounds on the flavor violating transitions allowed by current limits stemming from low energy processes, such as meson mixing and $b \rightarrow s \gamma$. We find that scenarios with vector-like quarks always have very suppressed flavor-violating transitions, while a general two Higgs doublet model may have a sizeable rate. To study the latter case in detail, we perform a full numerical simulation taking into account all relevant theoretical and phenomenological constraints. Our results show that ${\rm BR}(t\rightarrow ch)$ [${\rm BR}(h\rightarrow bs)$] are still allowed at the subpercent [percent] level, which are being [may be] explored at the LHC [future colliders]. Finally, we have found that the mild mass-splitting discrepancy with respect to the SM in the $B_s$ meson system can be accommodated in the Two-Higgs-Doublet Model. If confirmed, it yields the prediction ${\rm BR}(h\rightarrow bs)\simeq 10^{-4}$, if the new contribution to the mass-splitting is dominated by tree-level Higgs boson exchange., Comment: 38 pages, 13 figures, 9 tables

Data in $B$-meson decays indicate violations of lepton flavour universality, thereby raising the question about such phenomena in the charm sector. We perform a model-independent analysis of NP contributions in (semi)-leptonic decays of $D_{(s)}$ mesons which originate from $c \to d \bar{\ell} \nu_{\ell}$ and $c \to s \bar{\ell} \nu_{\ell}$ charge-current interactions. Starting from the most general low-energy effective Hamiltonian containing four-fermion operators and the corresponding short-distance coefficients, we explore the impact of new (pseudo)-scalar, vector and tensor operators and constrain their effects through the interplay with current data. We pay special attention to the elements $|V_{cd}|$ and $|V_{cs}|$ of the Cabibbo--Kobayashi--Maskawa matrix and extract them from the $D_{(s)}$ decays in the presence of possible NP decay contributions, comparing them with determinations utilizing unitarity. We find a picture in agreement with the Standard Model within the current uncertainties. Using the results from our analysis, we make also predictions for leptonic $D_{(s)}^+ \to e^+ \nu_e$ modes which could be hugely enhanced with respect to their tiny Standard Model branching ratios. It will be interesting to apply our strategy at the future high-precision frontier., Comment: 34 pages, 17 figures. v2: references added

We analyze the validity of a commonly used identification between structures of the virtual photon $\gamma^*\to Q\bar Q$ and vector meson $V\to Q\bar Q$ transitions. In the existing studies of $S$-wave vector-meson photoproduction in the literature, such an identification is typically performed in the light-front (LF) frame while the radial component of the meson wave function is rather postulated than computed from the first principles. The massive photon-like $V\to Q\bar Q$ vertex, besides the $S$-wave component, also contains an extra $D$-wave admixture in the $Q\bar Q$ rest frame. However, the relative weight of these contributions cannot be justified by any reasonable nonrelativistic $Q\bar Q$ potential model. In this work, we investigate the relative role of the $D$-wave contribution starting from the photon-like quarkonium $V\to Q\bar Q$ transition in both frames: in the $Q\bar Q$ rest frame (with subsequent Melosh spin transform to the LF frame) and in the LF frame (without Melosh transform). We show that the photon-like transition imposed in the $Q\bar Q$ rest frame leads to significant discrepancies with the experimental data. In the second case we find that the corresponding total $J/\psi(1S)$ photoproduction cross sections are very close to those obtained with the "$S$-wave only" $V\to Q\bar Q$ transition, both leading to a good description of the data. However, we find that the "$S$-wave only" transition leads to a better description of photoproduction data for excited heavy quarkonium states, which represent a more effective tool for study of $D$-wave effects. Consequently, the predictions for production of excited states based on the photon-like structure of $V\to Q\bar Q$ transition should be treated with a great care due to a much stronger sensitivity of the $D$-wave contribution to the nodal structure of quarkonium wave functions., Comment: 18 pages of Latex including 6 figures. The modified version which has been accepted for publication by European Physical Journal C

Heavy hadrons have been the focus of attention because of their worthwhile properties. So far the fragmentation function (FF) and total fragmentation probability (F.P) for heavy baryons and mesons have been calculated in quark model and diquark model in leading order of perturbative QCD. After the discovery of pentaquarks, their fragmentation probabilities were estimated based on the known measurementsof c or b quarks into mesons and baryons. In this note we calculate the direct fragmentation function of $$ \overline{c}\to {\varTheta}_c^0\left( uudd\overline{c}\right) $$ and $$ \overline{b}\to {\varTheta}_b^{+}\left( uudd\overline{b}\right) $$ processes in leading order of perturbative QCD, employing the diquark model with considerable precision. Consistent with such a process we set up the kinematics of the fragmentation of a heavy antiquark into a pentaquark such that the effect of the Fermi motion of the constituents is ignored. We show that using the diquark model for studying pentaquark can provide reasonably good theoretical results. The findings of this study accord with those in the previous studies.

We discuss for some particular non supersymmetric theories a generalized symmetry that includes both the scale and axial transformations and leads to a single current that may contain also a pseudoscalar term. The method, inspired by the superconformal anomalies has important application for low energy effective models where it allows the introduction of a single complex glueball field with a scalar and a pseudoscalar component on the same footing with the complex meson nonets fields made of quarks. Both axial and trace and axial anomalies are satisfied in accordance to the meson structure and the QCD requirements., Comment: 8 pages, accepted for publication in Advances in High Energy Physics

The study is dedicated to the multiplicity of momentum and angular characteristics of protons formed in nC-collisions at a pulse of 4.2 GeV/c. The experimental results on the formation of Δ0 isobars in nC-collisions at 4.2 GeV/c are presented for the first time. Experimental and normalised background distribution of the effective mass for protons and π−-mesons was obtained. This study is a follow-up to prior research. It explores various kinematic characteristics of π‒-mesons formed in nC-collisions at 4.2 GeV/c. The data obtained are compared with the experimental data obtained for pA interactions at the same energy. The experimental material used in this work was obtained using a 2-meter propane bubble chamber of the JINR LHE irradiated with beams of proton, deuteron and helium-4 nuclei at a pulse of 4.2 GeV/c per nucleon at the Dubna Synchrophasotron and consists of 6736 pC, 7071 dC and 11974 4HeC events. Negative π mesons are identified visually by the charge sign only.

We calculate the atmospheric flux of prompt neutrinos, produced in decays of the charmed particles at energies beyond 1 TeV. Cross sections of the $D$-mesons and ${\Lambda}^{+}_{c}$ baryons production in pA and $\pi$A collisions are calculated in the phenomenological quark-gluon string model (QGSM) which is updated using of the recent measurements of cross sections of the charmed meson production in the LHC experiments. A new estimate of the prompt atmospheric neutrino flux is obtained and compared with the limit of the IceCube experiment as well as with predictions of other charm production models., Comment: 15 pages, 18 figures; corrected text and figures, added references

We propose a new description of a baryon as a pair of mesons. This description is an extension of the previously proposed description of a nucleon as a pair of pions. The purpose of this article is to show the following two possibilities. The first one is that it shows the qualitative explanation to support our description of a nucleon as a pair of pions and the second one is that it gives the systematic way of estimation of baryon mass not only for light baryons but also for heavy baryons (charm baryons and bottom baryons). Each isospin group is constructed of both baryons and antibaryons. This way of construction is consistent with that of mesons. The results obtained are listed in tables (Tables 1-9). This shows that the generalized Gell-Mann-Nishijima relation equation holds under the condition that the baryon number is 0 and that the obtained masses are fairly good, even for heavy baryons. Our description also yields several examples of baryon decay modes.

Among the possible CP-odd couplings of the axion to ordinary matter, the most relevant ones for phenomenology are the Yukawa couplings to nucleons. We analyze such non-derivative couplings within three different approaches: standard effective field theory, the Skyrme model and holographic QCD. In all the cases, the couplings can be related to the CP-odd non-derivative couplings to nucleons of the low-lying mesons and the $\eta'$. Using the effective field theory approach we discuss how to derive the expressions for the CP-odd interaction terms as functions of the parameters of the effective Lagrangian at generic number of colors $N_c$ and flavors $N_f$. Then, we compute the CP-odd couplings to nucleons of the axion, the $\eta'$ and the pseudo-Goldstone mesons in both the Skyrme and the holographic QCD model with $N_f=2,3$. We present model-independent expressions for the coefficients of the non-derivative axion-nucleon couplings. This allows us to provide quantitative estimates of these couplings., Comment: v1: 45 pages + appendices, 1 figure; v2: typos corrected, references added; v3: 38 pages + appendices, 1 figure, section 4 added containing model-independent IR relations for the couplings, sections 3,5,6 re-edited, table 1 added and discussion section improved, review material moved to the appendices, comments and references added, typos corrected

We report results of our recent works [S. Narison, Int. J. Mod. Phys. A33 (2018) no. 10, 1850045; S. Narison. Addendum: Int. J. Mod. Phys. A33 (2018) no. 10, 1850045; S. Narison, Phys. Lett . B802 (2020) 135221.] where the correlations between the c,b -quark running masses m‾c,b , the gluon condensate 〈αsG2〉 and the QCD coupling αs in the MS‾ -scheme from an analysis of the charmonium and bottomium spectra and the Bc -meson mass. We use optimized ratios of relativistic Laplace sum rules (LSR) evaluated at the μ -subtraction stability point where higher orders PT and D≤6−8 -dimensions nonperturbative condensates corrections are included. We obtain [S. Narison, Int. J. Mod. Phys. A33 (2018) no. 10, 1850045; S. Narison. Addendum: Int. J. Mod. Phys. A33 (2018) no. 10, 1850045.] αs(2.85)=0.262(9) and αs(9.50)=0.180(8) from the (pseudo)scalar Mχ0c(0b)−Mηc(b) mass-splittings at μ=2.85(9.50) GeV. The most precise result from the charm channel leads to αs(Mτ)=0.318(15) and αs(MZ)=0.1183(19)(3) in excellent agreement with the world average: αs(MZ)=0.1181(11) [For a review, see e.g: S. Bethke, Nucl. Part. Phys. Proc . 282–284 (2017)149; C. Patrignani et al. (Particle Data Group), Chin. Phys . C40, 100001 (2016) and 2017 update.]. Updated results from a global fit of the (axial-)vector and (pseudo)scalar channels using Laplace and Moments sum rules @ N2LO [S. Narison, Int. J. Mod. Phys. A33 (2018) no. 10, 1850045; S. Narison. Addendum: Int. J. Mod. Phys. A33 (2018) no. 10, 1850045.] combined with the one from MBc [S. Narison, Phys. Lett . B802 (2020) 135221.] lead to the new tentative QCD spetral sum rules (QSSR) average: m‾c(m‾c)|average=1266(6) MeV and m‾b(m‾b)|average=4196(8) MeV. The values of the gluon condensate 〈αsG2〉 from the (axial)-vector charmonium channels combined with previous determinations in Table 1, leads to the new QSSR average: [S. Narison, Int. J. Mod. Phys. A33 (2018) no. 10, 1850045; S. Narison. Addendum: Int. J. Mod. Phys. A33 (2018) no. 10, 1850045.] 〈αsG2〉|average=(6.35±0.35)×10−2 Ge4 . Our results clarify the (apparent) discrepancies between different estimates of 〈αsG2〉 from J/ψ sum rule but also shows the sensitivity of the sum rules on the choice of the μ -subtraction scale. As a biproduct, we deduce the Bc -decay constants fBc=371(17) MeV and fBc(2S)≤139(6) MeV.

Through the introduced work a viable numerical scheme has been developed, using Numerov’s method, to study the energy spectra of mesons and hadronic interactions. Upon the implementation of...

Understanding the role of muons in Particle Physics is an important step understanding generations and the origin of mass as an expression of “internal structure”. A possible connection between muonic atoms and cycloatoms is used as a pretext to speculate on the above core issue of the Standard Model.

Using the “Aureum Geometric Model” (AGM) of quarks, we formulate the structure equations describing mesons and, by a mathematic procedure, we calculate the theoretical spectrum of mass values of light mesons without strangeness.

The decay constant of the η-meson in the framework of ‘resummed’ chiral perturbation theory is discussed. A theoretical prediction is compared to the available determinations. Compatibility of these determinations with the latest fits of the S U(3) low energy coupling constants is investigated. Preliminary results for the obtained constraints on the low energy coupling constants L 5 r and L 4 r , using Bayesian statistical approach, are presented.

The photon polarization in b→sγ transitions is measured for the first time in radiative b -baryon decays exploiting the unique spin structure of Λb0→Λγ decays. A data sample corresponding to an integrated luminosity of 6 fb−1 collected by the LHCb experiment in pp collisions at a center-of-mass energy of 13 TeV is used. The photon polarization is measured to be αγ=0.82−0.26−0.13+0.17+0.04, where the first uncertainty is statistical and the second systematic. This result is in agreement with the Standard Model prediction and previous measurements in b -meson decays. Charge-parity breaking effects are studied for the first time in this observable and found to be consistent with CP symmetry.

Heavy quark production in heavy ion collisions has been used as a probe of the strongly coupled quark gluon plasma in two ways. One is the study of the collision centrality and transverse momentum dependence of the modification of open heavy flavor yields in A+A collisions, which provides information about the coupling of the heavy quark to the medium. The other is the study of the modification of heavy quarkonia in A+A collisions, which provides information about the effect of the medium on the binding of these closed heavy flavor mesons. PHENIX has the ability to study both probes at midrapidity and at forward/backward rapidity. Recently, measurements of quarkonia production in $p(d)$+A collisions have shown strong modification of the more weakly bound quarkonia, at the same time that evidence of the formation of a small QGP in these light systems has been found. This proceedings presents results of measurements of separated charm and bottom open heavy flavor modification in Au+Au collisions, and charmonia production in $p$+Al and $p$+Au collisions.

Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb(-1) collected with the LHCb detector, seven decay modes of the B-C(+) meson into a J/psi or psi(2S) meson and three charged hadrons, kaons or pions, are studied. The decays B-C (+)-> (psi(2S) -> J/psi pi(+)pi(-))pi(+), B+C -> (psi(2S)pi(+)pi(-)pi(+), B+C -> J/psi K+pi(-)pi(+) and B+C -> J/K+K-K+ are observed for the first time, and evidence for the B-C (+)-> (psi(2S)K+K-pi(+), decay is found, where J/psi and psi(2S) mesons are reconstructed in their dimuon decay modes. The ratios of branching fractions between the different B-C(+) decays are reported as well as the fractions of the decays proceeding via intermediate resonances. The results largely support the factorisation approach used for a theoretical description of the studied decays.

Using proton-proton collision data, corresponding to an integrated luminosity of 9 fb(-1) collected with the LHCb detector, seven decay modes of the B-C(+) meson into a J/psi or psi(2S) meson and three charged hadrons, kaons or pions, are studied. The decays B-C (+)-> (psi(2S) -> J/psi pi(+)pi(-))pi(+), B+C -> (psi(2S)pi(+)pi(-)pi(+), B+C -> J/psi K+pi(-)pi(+) and B+C -> J/K+K-K+ are observed for the first time, and evidence for the B-C (+)-> (psi(2S)K+K-pi(+), decay is found, where J/psi and psi(2S) mesons are reconstructed in their dimuon decay modes. The ratios of branching fractions between the different B-C(+) decays are reported as well as the fractions of the decays proceeding via intermediate resonances. The results largely support the factorisation approach used for a theoretical description of the studied decays.

Unlike the octet baryons for $N_f=3$, there is no skyrmion coming from the $\eta^\prime$ meson. It is instead described as a fractional quantum Hall droplet, a pancake or a pita involving a singular $\eta^\prime$ ring in which Chern-Simons fields live. By incorporating hidden local symmetry and hidden scale symmetry in nuclear dynamics, I describe how to access baryon-charged quantum Hall droplets in dense nuclear matter in terms of the nuclear scale-chiral effective field theory approach ``G$n$EFT" with the $U_A(1)$ anomaly taken into account. I discuss how the single-flavor baryon that I will call ${\cal B}^s$ could be exposed in superdense baryonic matter, figuring, perhaps, in ``quark stars" associated with the baryon-quark continuity involving CFL or phase transitions., Comment: 8 pages, no figures

Physical review letters 128(8), 081804 (2022). doi:10.1103/PhysRevLett.128.081804, We search for a light Higgs boson ($A^0$) decaying into a $\tau^+\tau^-$ or $\mu^+\mu^-$ pair in the radiative decays of $\Upsilon(1S)$. The production of $\Upsilon(1S)$ mesons is tagged by $\Upsilon(2S)\to \pi^+ \pi^- \Upsilon(1S)$ transitions, using 158 million $\Upsilon(2S)$ events accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant $A^0$ signals in the mass range from the $\tau^+\tau^-$ or $\mu^+\mu^-$ threshold to 9.2 GeV/$c^2$ are observed. We set the upper limits at 90% credibility level (C.L.) on the product branching fractions for $\Upsilon(1S)\to \gamma A^0$ and $A^0\to \tau^+\tau^-$ varying from $3.8\times10^{-6}$ to $1.5\times10^{-4}$. Our results represent an approximately twofold improvement on the current world best upper limits for the $\Upsilon(1S)\to \gamma A^0(\to \tau^+\tau^-)$ production. For $A^0\to \mu^+\mu^-$, the upper limits on the product branching fractions for $\Upsilon(1S)\to \gamma A^0$ and $A^0\to \mu^+\mu^-$ are at the same level as the world average limits, and vary from $3.1\times10^{-7}$ to $1.6\times10^{-5}$. The upper limits at 90% C.L. on the Yukawa coupling $f_{\Upsilon(1S)}$ and mixing angle ${\rm sin}\theta_{A^0}$ are also given., Published by APS, College Park, Md.

Master-field simulations offer an approach to lattice QCD in which calculations are performed on a small number of large-volume gauge-field configurations. The latter is advantageous for simulations in which the global topological charge is frozen due to a very fine lattice spacing, as the effect of this on observables is suppressed by the spacetime volume. Here we make use of the recently developed Stabilised Wilson Fermions to investigate a variation of this approach in which only the temporal direction ($T$) is taken larger than in traditional calculations. As compared to a hyper-cubic lattice geometry, this has the advantage that finite-$L$ effects can be useful, e.g. for multi-hadron observables, while compared to open boundary conditions, time-translation invariance is not lost. In this proof-of-concept contribution, we study the idea of using very cold (i.e. long-$T$) lattices to topologically "defrost" observables at fine lattice spacing. We identify the scalar-scalar meson two-point correlation function as a useful probe and present first results from $N_f=3$ ensembles with time extents up to $T=2304$ and a lattice spacing of $a=0.055\,\rm{fm}$., Comment: 10 pages, 4 figures, 1 table, to be published in Proceedings of Science, contribution to "The 39th International Symposium on Lattice Field Theory (LATTICE 2022)"

Based on (10087±44)×10^{6} J/ψ events collected with the BESIII detector, the process J/ψ→γπ^{+}π^{-}η^{'} is studied using two largest decay channels of the η^{'} meson, η^{'}→γπ^{+}π^{-} and η^{'}→ηπ^{+}π^{-}, η→γγ. A new resonance, which we denote as the X(2600), is observed with a statistical significance larger than 20σ in the π^{+}π^{-}η^{'} invariant mass spectrum, and it has a connection to a structure around 1.5 GeV/c^{2} in the π^{+}π^{-} invariant mass spectrum. A simultaneous fit on the π^{+}π^{-}η^{'} and π^{+}π^{-} invariant mass spectra with the two η^{'} decay modes indicates that the mass and width of the X(2600) state are 2618.3±2.0_{-1.4}^{+16.3} MeV/c^{2} and 195±5_{-17}^{+26} MeV, where the first uncertainties are statistical, and the second systematic. 2-s2.0-85135552304

We present preliminary results from our calculation of the pseudoscalar transition form factors of the $\eta$ and $\eta'$ mesons using staggered quarks on $N_f=2+1+1$ gauge ensembles generated by the Budapest-Marseille-Wuppertal collaboration. These transition form factors are an important input for the hadronic light-by-light contribution to the muon $(g-2)$. We first elaborate on the extraction of the masses of the $\eta$ and $\eta'$ mesons, that mix under the dynamics of QCD. Thereafter, we show our preliminary results for the pseudoscalar transition form factors, focusing on the $\eta$ meson in the absence of mixing., Comment: 9 pages, 7 figures, The 38th International Symposium on Lattice Field Theory, LATTICE2021 26th-30th July, 2021, Zoom/Gather@Massachusetts Institute of Technology

The electromagnetic interactions of hadrons serve as a valuable probe of the nature of the strong force at low energies and simultaneously allow for tests of fundamental discrete symmetries. In this thesis, I show how polarization observables can be used to gain an in-depth understanding of these processes and present two analyses of data from the BESIII experiment where such observables have been studied. In the first part of the thesis, I report on a study of the rare decay η' → π+π-e+e- based on a sample of 1.3×109 e+e- → J/ψ events using the J/ψ → γη' radiative decay as a source of η' mesons. The branching fraction is measured to be (2.42±0.05stat.±0.08syst.)×10-3 with statistical precision a factor of two better than the previous best measurement. Furthermore, I investigate the possibility of a CP-violating contribution to the decay beyond the standard model which would lead to an asymmetry in the angle between the decay planes of the e+e-- and π+π--pairs. The asymmetry is measured to be (2.9±3.7stat.±1.1syst.)%, consistent with zero in agreement with the standard model expectation of no CP-violation. In the second part of the thesis, the reaction e+e- → Λ anti-Λ is studied at five center-of-mass energies from 2.3864 GeV to 3.0800 GeV. A combination of fully and partially reconstructed events is used to measure the Born cross section for the process and determine the ratio and the relative phase of the timelike electromagnetic form factors of the Λ hyperon. Finally, I present a benchmark test of the tracking software for the planned upgrade of the BESIII detector with a new cylindrical gas electron-multiplier tracker.