Strong-coupling expansions for the off-axis glueball masses

Strong-coupling expansions, up to order g^?4, for the off-axis glueball masses are developed in four-dimensional spacetime for lattice gauge theories with gauge groups SU(2), SU(3), Z₂, Z₃. Glueball mass spectra for the states 0⁺⁺, 2⁺⁺, 1^+? are obtained. Restoration of Lorentz invariance is discussed.     

Masses of lowest lying heavy mesons in QCD

Using QCD sum rules for the polarization operator ∏^J(Q²) induced by all possible currents with J^PC=0^??, 1^??, 0⁺⁺, 1⁺⁺ and 2⁺⁺ we calculate the S- and P-states of charmonium. Power corrections due to the gluon condensate operator G^α_μνG^α_μν are included and shown to be very important. All known lowest lying charmonium states are reproduced extremely well and a firm prediction is made for the ¹P₁ state.     

Calculation of the glueball mass spectrum ofSU (2) andSU (3) non-abelian lattice gauge theories II:SU (3)

We calculate the glueball mass spectrum in theSU (3) lattice regularized gauge theory. We find fourlight glueballs: the 0⁺⁺, 2⁺⁺, 0^?+ and, most interestingly from the experimental point of view, the oddball 1^?+. We calculate the 0⁺⁺ and 2⁺⁺ masses over a range of β values and find thatboth states conform to continuum renormalization group behaviour to a very significant degree. The question of metastable states and temperature is addressed in detail. Finally we discuss and resolve contrary claims in the recent literature.     

Sum rules for the decays of the c-even charmonium states

Sum rules for the decays of the C-even charmonium levels (¹S₀, ³P₀, ³P₂, ¹D₂) are derived. These rules are based on the asymptotic freedom of the quantum chromodynamics at small distances and on the analyticity. They refer to the various vacuum amplitudes involving products of charmed quark currents: electromagnetic current as well as currents with quantum numbers J^PC=0^?+,0⁺⁺,2⁺⁺,2^?+. The contribution of the continuum to some of the sum rules is small, and they are saturated by the contribution of the lowest charmonium levels. In this way we predict the widths of the two-photon decays of the charmonium states and estimate their total hadronic widths.     

Increased statistics and observation of the gT,gT′, and gT′' 2++resonances in the Glueball enhanced channel π−p→φφn

In a new experiment we have obtained 3006 new events in the reaction π⁻p→φφn, approximately doubling the statistics which now total 6658. A refined partial wave analysis of the φφ system again reveals three resonances (g_T, g_T′, g_T′') with I^GJ^PC=0⁺2⁺⁺. The absence of the OZI suppression, and the observation of only three J^PC=2⁺⁺ states (g_T, g_T′, g_T′') which comprise virtually all the cross section are unusual characteristics of the data. The large φφn signal occurs over a mostly structureless and incoherent φK⁺K⁻n background. All these unusual characteristics are well explained if these states are produced by 1–3 glueballs (multigluon resonances).     

A transverse gluonium potential model with Breit-fermi hyperfine effects

We introduce a potential model of bound transverse gluons with a fictitious constitutent mass. The gluonic Breit hamiltonian due to one gluon exchange is derived, and its effect on thegg spectrum is estimated; hyperfine corrections are large, but not nonperturbatively so. We find a degenerate (0⁺⁺, 0^?+) ground state and a first 2⁺⁺ excitation at ～1.2M ₀. Our list ofgg states disagrees with some sources, due to the absence of unphysical longitudinal degrees of freedom in the model.     

Evidence for two strangeonium resonances with JPC=1++ and 1+− in K−p interactions at 11 GeV/c

The results of a partial wave analysis of the low mass KK̄π system produced in the reactions K⁻p→K⁰_sK^±π^±Λ at 11 GeV/c using the LASS spectrometer are presented. Evidence is given for two ss̄ axial-vector meson states: one with quantum numbers J^PC = 1⁺⁺, mass ∼ 1530 MeV/c², and width ∼ 100 MeV/c², and the other with quantum numbers J^PC=1⁺⁻, mass ∼ 1380 MeV/c², and width ∼ 80 MeV/c². These states are good candidates to be the mostly strangeonium members of the ground state 1⁺⁺ and 1⁺⁻ nonets predicted by the quark model.     

Two-pion spectra for the reaction π− p → π0π0 n at a pion momentum of 38 GeV/c and combined analysis of GAMS, Crystal Barrel, and BNL data

We perform a K-matrix analysis of IJ ^PC =00⁺⁺, 10⁺⁺, 02⁺⁺, and 12⁺⁺ meson partial waves using GAMS data on π^? p → π⁰π⁰ n, ηηn, ηη'n that are supplemented with BNL data on π^? p → K $\bar K$ n and Crystal Barrel data on p $\bar p$ (at rest) → π⁰π⁰π⁰, π⁰ηη, π⁰π⁰η. The positions of the amplitude poles (physical resonances) are determined, together with the positions of the K-matrix poles (bare states) and the values of barestate couplings to two-meson channels. The nonet classification of the bare states found in the present analysis is discussed.     

SU(3) lattice Monte Carlo calculation of the glueball mass spectrum

We have calculated the glueball masses of various spins and parities in SU(3) gauge theory. Our first results give m_M(0⁺⁺)=(3.6±0.2)Λ_mom, m_E(0⁺⁺)=(4.3±0.3)Λ_mom, m(0^?+)=(7.2_?0.9^+1.6)Λ_mom, m_M(2⁺⁺)=(8.1±1.1)Λ_mom and m_E(2⁺⁺)=(8.3_?1.0^+1.6)Λ_mom as well as information on the glueball wave functions.     

Spectral function sum rules for gluonic currents

We determine the masses and the decay amplitudes of the 2⁺⁺, 0^?+ and 0⁺⁺ gluonia in anSU(3) _c Yang-Mills theory. We estimate the so-called topological susceptibility of theU(1) sector. We discuss theSU(3) _F breaking effects to the η′(896) massrelation from current algebra and predict the η′ parameter values.     

Glueballs: Their experimental signature

We study hadrons with a 2-gluon valence component, emphasizing states not found in the quark model. We predict that 0⁺⁺, 0^?+, 1⁺⁺, and the particularly interesting 1^?+ glueballs will be narrow, with widths ranging from a few MeV to less than one MeV, and that spin 0 glueballs will mimic ss? quarkonium states in their decay. We also comment on photonic couplings.     

The small-volume expansion of gauge theories coupled to massless fermions

The small-volume expansion of the low-lying glueball states for SU(2) and SU(3) gauge theory, coupled to massless fermions with periodic and antiperiodic boundary conditions, is determined. For SU(3) with periodic boundary conditions the vacuum is eightfold degenerate and breaks part of the cubic group spontaneously. In all cases the scalar-to-tensor mass ratio m_A1⁺⁺/m_E⁺⁺ is 1.1 to 1.3 as in the pure-gauge case. We also discuss chiral symmetry.     

Constructing local composite operators for glueball states from a confining Gribov propagator

The construction of BRST invariant local operators with the quantum numbers of the lightest glueball states, J ^PC=0⁺⁺,2⁺⁺,0^?+, is worked out by making use of an Euclidean confining renormalizable gauge theory. The correlation functions of these operators are evaluated by employing a confining gluon propagator of the Gribov type and shown to display a spectral representation with positive spectral densities. An attempt to provide a first qualitative analysis of the ratios of the masses of the lightest glueballs is also discussed.     

The mass spectrum of 0−+, 0++, 1−-, 2++ mesons in the SU(4) and SU(8) scheme and prediction of new narrow resonances

A unified treatment of 0^?+, 0⁺⁺, 1^?-, 2⁺⁺ meson multiplets is provided, in the SU(4) and SU(8) scheme. The overall consistence is excellent and the existence of a new 1^?- resonance φ_c(2.835) is predicted.     

Exotic states X ±(1600, I G (J PC)=2+ (2++)) in photoproduction reactions

It is shown that the list of unusual mesons that are planned to be studied in photoproduction reactions can be supplemented with I ^G (J ^PC)=2⁺ (2⁺⁺) exotic states X ^±(1600), which are natural to seek as manifestations of the ρ^±ρ⁰ decay channels in the reactions γN → ρ^±ρ⁰ N and γN → ρ^±ρ⁰Δ. A classification of the ρ^±ρ⁰ states according to their quantum numbers is presented. A model for the spin structure of the amplitudes for the reactions γp → f ₂(1270)p, γp → a ₂ ⁰ (1320)p, and γN → X ^±(N, Δ) is proposed, and estimates are obtained for the corresponding cross sections. At E _γ≈6 GeV, it is found that σ(γP → f ₂(1270)p)≈0.12 μb, σ(γp → a ₂ ⁰ (1320)p)≈0.25 μb, σ(γN → X ^± N → ρ^±ρ⁰ N) ≈ 0.018 μb, and σ(γp → X ⁻Δ⁺⁺ → ρ⁻ρ⁰Δ⁺⁺≈0.031 μb. The problem of isolating signals from X ^± states against the natural background that is associated with other channels of π^±π⁰π⁺π⁻ production is discussed. It is deduced that searches for exotic states X ^±(2⁺ (2⁺⁺)) in experiments at JLAB will be quite efficient—for example, the yield of about 2.8×10⁶ events per month is expected to correspond to the estimated cross sections for the reactions γN → X ^± N → ρ^±ρ⁰ N. __________ Translated from Yadernaya Fizika, Vol. 63, No. 10, 2000, pp. 1904–1912. Original Russian Text Copyright ? 2000 by Achasov, Shestakov.     

Spectroscopic constants of the known electronic states of lead monofluoride

Based on measurements made by mass-resolved 1 + 1′ + 1″ resonance-enhanced multiphoton ionization spectroscopy, we have determined new molecular constants describing the rotational and fine structure levels of the B, D, E, and F states of the most abundant isotopic variant ²⁰⁸Pb¹⁹F, and we summarize the spectroscopic constants for all the know electronic states of the radical. Many spectroscopic constants for the isotopologues ²⁰⁶Pb¹⁹F and ²⁰⁷Pb¹⁹F have also been determined. The symmetry of the D-state is found to be ²Π_1/2, and the F-state is found to be an Ω = 3/2 state.     

Radiative transitions and the P wave levels in charmonium

A value of $\text{1}\text{2}$ or less for the ratio $\text{[E(2}{}^{\mathrm{++}}\text{) ? E(1}{}^{\mathrm{++}}\text{)]}\text{[E(1}{}^{\mathrm{++}}\text{) ? E(0}{}^{\mathrm{++}}\text{)]}$ of the P level splittings in approximate agreement with the assignment of the states at 3.41, 3.50 and 3.55 to the 0⁺⁺,and 2⁺⁺ P-wave levels, is obtained with a short-range Coulomb (Lorentz vector) potential together with a long-range linear (Lorentz scalar) confining potential. The radiative transition widths Γ(ψ′ → 3.41 + γ), Γ(ψ′ → 3.50 + γ), Γ(χ′ → 3.55 + γ) are significantly smaller than those obtained in previous (one-channel) charmonium calculations. The best results were obtained by allowing the Coulomb coupling constant α_s to have a momentum dependence suggested by asymptotic freedom formulae.     

Measurement of hadronic production of the χ1++(3507) and the χ2++(3553) through their radiative decay to Jϕ

The _χ1⁺⁺(3507) and the _χ2⁺⁺(3553) states have been observed in the Goliath spectrometer at the CERN SPS in 185 GeV/cπ^?-Be collisions. Their radiative decays contribute 27.7% (for the χ₁⁺⁺) and 12.8% (for the χ₂⁺⁺) to $\text{J}\text{?}$ production. At this energy, their cross sections are 65±19 nb and 96±29 nb, respectively     

Weak decays of doubly heavy baryons: “decay constants”

Inspired by the recent observation of the Ξ_c~+_c~+)by the LHCb Collaboration, we explore the "decay constants" of doubly heavy baryons in the framework of QCD sum rules. With the Ξ_cc),Ξ_(bc),Ξ_(bb), and ?_(cc),?_(bc),?_(bb) baryons interpolated by three-quark operators, we calculate the correlation functions using the operator product expansion and include the contributions from operators up to dimension six. On the hadron side, we consider both contributions from the lowest-lying states with JP=1/2~+ and from negative parity baryons with JP=1/2~-. We find that the results are stable and the contaminations from negative parity baryons are not severe. These results are ingredients for the QCD study of weak decays and other properties of doubly-heavy baryons.