120878753
Measurements of dilepton production in nucleon-nucleon interactions
6986761
Threshold behavior of electron pair production in p-Be collisions.
We report on the measurements of electron pair production in /ital p/-Becollisions at 1.0, 2.1, and 4.9 GeV beam kinetic energies. The invariant-massand transverse-momentum spectra are presented, along with the total crosssections. A rapid decrease in the integrated cross section is observed as thebeam energy is reduced. Comparison of the excitation function for dielectron(/ital e//sup +/e/sup /minus//) and dipion (..pi../sup +/..pi../sup /minus//)production suggests that the dominant production mechanism at beam kineticenergies 2.1 and 4.9 GeV may be ..pi../sup +/..pi../sup /minus// annihilation.
120239957
Threshold behavior of direct electron production in proton‐beryllium collisions
We report measurements of direct electron pair production in p‐Be interactions at 1.0, 2.1 and 4.9 GeV kinetic beam energies. The invariant mass and pt spectra along with the total cross sections are presented. A rapid decrease in the total cross section is observed at the lowest energy.
117522082
First results on dilepton production at the Bevalac
We report on preliminary results of direct electron pair measurements in p+Be at 4.9 GeV and 2.1 GeV and Ca+Ca at 1.95 GeVA collisions at the Bevalac. The results are compared to existing data in p+Be at 12.1 GeV and ..pi../sup -/p at 15.9 and 16.9 GeV.
119395992
Dilepton production from p-p to CaCa at the Bevalac
Abstract The DLS collaboration has recently completed a high statistics study of dilepton production at the Bevalac. In particular, we have measured dielectrons (e + e − ) from p - p and p - d collisions to understand the basic dilepton production mechanisms in the energy range from 1.05 – 4.9 GeV. These data can be used to determine the basic processes which contribute to nucleon-nucleon dilepton production such as hadronic bremsstrahlung, vector meson processes, and hadronic Dalitz decay. The data show that a simple elastic bremsstrahlung calculation is insufficient to explain the data. Theoretical models are compared with the data. A new high statistics study of Ca  Ca at 1.05 A·GeV has been made to study the collectivity of A - A collisions.
44598663
Measurement of dielectron production in niobium-niobium collisions at 1.05 GeV/nucleon.
A dielectron signal for pair masses greater than [ital M][sub [pi]] is observed in Nb+Nb collisions at 1.05 GeV/nucleon beam kinetic energy. The invariant mass spectrum and the associated multiplicity distribution are presented. Comparisons are made with previous cross section measurements in [ital p]+Be and Ca+Ca.
59247128
Quantum field theory on quantized Bergman domain
We present an oscillator realization of discrete series representations of group SU(2, 2). We give formulas for the coherent state star-product quantization of a Bergman domain D. A formulation of a (regularized) noncommutative scalar field on a quantized D is given.
119184301
The Zb(10610) and Zb(10650) as axial-vector tetraquark states in the QCD sum rules
Abstract In this article, we study the axial-vector mesons Z b ( 10 610 ) and Z b ( 10 650 ) with the C γ μ – C γ 5 type and C γ μ – C γ ν type interpolating currents, respectively, by carrying out the operator product expansion to the vacuum condensates up to dimension 10. In calculations, we explore the energy scale dependence of the QCD spectral densities of the hidden bottom tetraquark states in detail for the first time, and suggest a formula μ = M X / Y / Z 2 − ( 2 M b ) 2 with the effective mass M b = 5.13 GeV to determine the energy scales. The numerical results favor assigning the Z b ( 10 610 ) and Z b ( 10 650 ) as the C γ μ – C γ 5 type and C γ μ – C γ ν type hidden bottom tetraquark states, respectively. We obtain the mass of the J PC = 1 + + hidden bottom tetraquark state as a byproduct, which can be compared to the experimental data in the futures. Furthermore, we study the strong decays Z b ± ( 10 610 ) → ϒ π ± , η b ρ ± with the three-point QCD sum rules, the decay widths also support assigning the Z b ( 10 610 ) as the C γ μ – C γ 5 type hidden bottom tetraquark state.
119634202
On enriching the Levin–Wen model with symmetry
Symmetry protected (SPT) and symmetry enriched topological (SET) phases of matter are of great interest in condensed matter physics due to new materials such as topological insulators. The Levin?Wen (LW) model for spin/boson systems is an important rigorously solvable model for studying 2D topological phases. The input data for the LW model is a unitary fusion category, but the same model also works for unitary multi-fusion categories. In this paper, we provide the details for this extension of the LW model, and show that the extended LW model is a natural playground for the theoretical study of SPT and SET phases of matter.
14170238
Mass spectrum of the scalar hidden charm and bottom tetraquark states
In this article, we study the mass spectrum of the scalar hidden charm and bottom tetraquark states with the QCD sum rules. The numerical results are compared with the corresponding ones from a relativistic quark model based on a quasipotential approach in QCD. The relevant values from the constituent diquark model based on the constituent diquark masses and the spin-spin interactions are also discussed.
115170347
Loop Vertex Expansion for Phi^2k Theory in Zero Dimension
In this paper we extend the method of loop vertex expansion to interactions with degree higher than 4. As an example we provide through this expansion an explicit proof that the free energy of Phi^2k scalar theory in zero dimension is Borel-Le Roy summable of order k-1. We detail the computations in the case of a Phi^6 interaction.