15517407
Determining the gluonic content of isoscalar mesons
We develop tools to determine the gluonic content of a resonance of known mass, width, and J{sup PC} from its branching fraction in radiative quarkonium decays and production cross section in {gamma}{gamma} collisions. We test the procedures by applying them to known q{bar q} mesons, then analyze four leading glueball candidates. We identify inconsistencies in data for J/{psi}{r_arrow}{gamma}f{sub 0}(1500) and J/{psi}{r_arrow}{gamma}f{sub J}(1710) whose resolution can quantify their glueball status. When {Gamma}(f{sub 0}(1500){r_arrow}{gamma}{gamma}) and {Gamma}(f{sub J}(1710){r_arrow}{gamma}{gamma}) are known, the n{bar n},s{bar s},gg mixing angles can be determined. The enigmatic situation in the 1400-1500 MeV region of the isosinglet 0{sup {minus}+} sector is discussed. {copyright} {ital 1997} {ital The American Physical Society}
120492049
Octupole degree of freedom for nuclei near 152Sm in a reflection-asymmetric relativistic mean-field approach
The potential energy surfaces of even-even isotopes near 152Sm are investigated within the constrained reflection-asymmetric relativistic mean-field approach using parameter sets PK1 and NL3. It is shown that the critical-point candidate nucleus 152Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole deformed ground state in 150Sm to the quadrupole deformed ground state in 154Sm. The important role of the octupole deformation driving pair (?2f7/2, ?1i13/2) is demonstrated based on the components of the single-particle levels near the Fermi surface. In addition, the patterns of both the proton and the neutron octupole deformation driving pairs (?2f7/2, ?1i13/2) and (?2d5/2, ?1h11/2) are investigated.
119334067
Longitudinal transitions of baryon resonances in the constituent quark model
A longitudinal transition operator that satisfies the gauge invariance requirement is introduced in the constituent quark model. The corresponding longitudinal transitions from the ground state of the nucleon to resonances of the baryon are calculated. The study shows that the longitudinal coupling plays an important role in the understanding of the structure of the baryon.
16718501
The Kaon-Photoproduction Of Nucleons In The Chiral Quark Model
In this paper, we develop a general framework to study the mesonphotoproductions of nucleons in the chiral quark model. The S and U channel resonance contributions are expressed in terms of the ChewGoldberger-Low-Nambu (CGLN) amplitudes. The kaon-photoproduction processes, γp → K+Λ, γp → K+Σ0, and γp → K0Σ+, are calculated. The initial results show that the quark model provides a much improved description of the reaction mechanism for the kaon-photoproductions of the nucleon with less parameters than the traditional phenomenological approaches. PACS numbers: 13.75.Gx, 13.40.Hq, 13.60.Le,12.40.Aa
33315431
Spin structure of nucleons in a quark model with constituent gluons.
55936188
Effect of time-odd mean fields on inertial parameters of the quadrupole collective Hamiltonian
Most current implementations of the quadrupole collective Hamiltonian model do not include the contributions of time-odd mean fields to the moments of inertia and mass parameters (Thouless-Valatin dynamical rearrangement contributions). A hybrid model is introduced that allows a quantitative estimate of these contributions to the inertial functions of a five- dimensional collective Hamiltonian based on microscopic energy density functionals. Fully self-consistent constrained relativistic Hartree-Bogoliubov calculations of triaxial energy surfaces in the β−γ plane are used to determine the parameters of an equivalent pairing-plus-quadrupole (P+Q) Hamiltonian. This Hamiltonian is employed in constrained Hartree-Fock- Bogoliubov (CHFB) plus local quasiparticle random-phase approximation (LQRPA) calculation of the deformation- dependent corrections to the Inglis-Belyaev moments of inertia and cranking mass parameters. This hybrid model is used to evaluate the influence of time-odd mean fields on vibrational and rotational collective masses and investigate their effect on the low-energy collective excitation spectra and transition rates of γ-soft Xe and Ba nuclei.
119444616
Reexamined radiative decay B*(q) ---> B(q gamma) in light cone QCD
The radiative decay $ B_{q}^*\to B_{q}\gamma(q=u,d, or s) $ is reexamined with a modified light-cone QCD sum rule method, in which adequate chiral operators are chosen as the interpolating fields in the correlators used for a sum rule estimate of the relevant coupling $ g_{B_{q}^*B_{q}\gamma} $. The resulting sum rules not only show the physical picture consistent with the underlying physics in $ B_{q}^*\to B_{q}\gamma $ but also avoid the pollution by the nonlocal matrix element $ $, which starts with twist-3 and thus may bring a large uncertainty to the sum rule predictions. Also, a comparison is made with the previous results from light-cone QCD sum rules and chiral perturbation theory.
119264529
Next-to-leading order QCD effects in associated charged Higgs and W boson production in the MSSM at the CERN Large Hadron Collider
We present the calculations of the next-to-leading order (NLO) QCD corrections to the inclusive total cross sections for the associated production of the ${W}^{\ifmmode\pm\else\textpm\fi{}}{H}^{\ensuremath{\mp}}$ through $b\overline{b}$ annihilation in the minimal supersymmetric standard model at the CERN Large Hadron Collider. The NLO QCD corrections can either enhance or reduce the total cross sections, but they generally efficiently reduce the dependence of the total cross sections on the renormalization/factorization scale. The magnitude of the NLO QCD corrections is about 10% in most of the parameter space and can reach 15% in some parameter regions. We also show the Monte Carlo simulation results for the $2j+{\ensuremath{\tau}}_{\mathrm{jet}}+{\mathrm{p\ensuremath{\llap{\not\;}}}}_{T}$ signature from the ${W}^{\ifmmode\pm\else\textpm\fi{}}$ and the ${H}^{\ensuremath{\mp}}$ decays including the NLO QCD effects, and find an observable signal at a $5\ensuremath{\sigma}$ level in some parameter region of the minimal supergravity model.
118664723
New parton distributions for collider physics
We extract new parton distribution functions (PDFs) of the proton by global analysis of hard scattering data in the general-mass framework of perturbative quantum chromodynamics. Our analysis includes new theoretical developments together with the most recent collider data from deep-inelastic scattering, vector boson production, and single-inclusive jet production. Because of the difficulty in fitting both the D0 Run-II W lepton asymmetry data and some fixed-target DIS data, we present two families of PDFs, CT10 and CT10W, without and with these high-luminosity W lepton asymmetry data included in the global analysis. With both sets of PDFs, we study theoretical predictions and uncertainties for a diverse selection of processes at the Fermilab Tevatron and the CERN Large Hadron Collider.
119073126
Improved approach to the heavy to light form-factors in the light cone QCD sum rules
A systematic analysis shows that the main uncertainties in the form factors are due to the twist-3 wave functions of the light mesons in the light-cone QCD sum rules. We propose an improved approach, in which the twist-3 wave functions do not make any contribution and therefore the possible pollution by them can be avoided, to reexamine B-->pi semileptonic form factors. Also, a comparison between previous results and our results from the light-cone QCD sum rules is made. Our method will be beneficial to the precise extraction of \V-ub\ from the experimental data on the processes B-->pil )over tilde>(l).
124137012
Study of in-medium Delta Delta elastic scattering cross section