326670
Limits on sizes of fundamental particles and on gravitational mass of a scalar
We review the experimental limits on mass of excited fundamental particles and contact interaction energy scale parameters Λ for QCD, QED and electroweak reactions. In particular we have focused on the QED reaction measuring the differential cross-sections for the process e+e−→γγ(γ) at the energies from 91 GeV to 202 GeV using the data collected with the L3 detector from 1991 to 1999. With a global fit we set lower limits at 95% CL on Λ>1687 GeV, which restricts the characteristic QED size of the interaction region to Re<1.17×10−17 cm. All the interaction regions are found to be smaller than the Compton wavelength of the fundamental particles. This constraint is used to estimate a lower limit on the size of a fundamental particle related to gravitational interaction, applying the model of self-gravitating particle-like structure with the de Sitter vacuum core. It gives rτ⩾2.3×10−17 cm and re⩾1.5×10−18 cm, if leptons get masses at the electroweak scale, and rτ⩾3.3×10−27 cm,re⩾4.9×10−26 cm, as the most stri...
117183376
Test of non point‐like behavior of Fermions
We search in measurements from LEP, TRISTAN, CDF, D0 and UA1 for those phenomena beyond the Standard Model where the fundamental particles can exhibit non point‐like behavior. The total and differential cross sections for the reaction e+e− → γγ(γ) measured at center‐of‐mass energies from 55 GeV to 207 GeV are used for a global fit to test the hypothesis of an excited electron and contact interaction induced terms. The best value for the fit exhibits an approximately 5 σ effect for the scale factor of an excited electron of (1/Λ±4)best = −(1.11 ± 0.20) × 10−10 GeV−4 and the scale of contact interaction of (1/Λ4)best = −(4.05 ± 0.73) × 10−13 GeV−4 but with the opposite to the expected in the modified cross section sign. An empirical scheme is discussed to encompass all fermions and bosons in one framework, if these particles would be geometrically extended objects.
118632272
Multidimensionally-constrained relativistic mean-field models and potential-energy surfaces of actinide nuclei
Background: Many different shape degrees of freedom play crucial roles in determining the nuclear ground state and saddle point properties and the fission path. For the study of nuclear potential energy surfaces, it is desirable to have microscopic and self-consistent models in which all known important shape degrees of freedom are included. Purpose: By breaking both the axial and the spatial reflection symmetries simultaneously, we develop multidimensionally-constrained relativistic mean field (MDC-RMF) models. Methods: The nuclear shape is assumed to be invariant under the reversion of x and y axes, i.e., the intrinsic symmetry group is V-4 and all shape degrees of freedom beta(lambda mu) with even mu, such as beta(20), beta(22), beta(30), beta(32), beta(40), ..., are included self-consistently. The single-particle wave functions are expanded in an axially deformed harmonic oscillator (ADHO) basis. The RMF functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the nonlinear or density- dependent couplings. The pairing effects are taken into account with the BCS approach. Results: The one-, two, and three-dimensional potential energy surfaces of Pu-240 are illustrated for numerical checks and for the study of the effect of the triaxiality on the fission barriers. Potential energy curves of even-even actinide nuclei around the first and second fission barriers are studied systematically. Besides the first ones, the second fission barriers in these nuclei are also lowered considerably by the triaxial deformation. This lowering effect is independent of the effective interactions used in the RMF functionals. Further discussions are made about different predictions on the effect of the triaxiality between the macroscopic-microscopic and MDC-RMF models, possible discontinuities on PES's from self-consistent approaches, and the restoration of broken symmetries. Conclusions: MDC-RMF models give a reasonably good description of fission barriers of even-even actinide nuclei. It is important to include both the nonaxial and the reflection asymmetric shapes simultaneously for the study of potential energy surfaces and fission barriers of actinide nuclei and of those in unknown mass regions such as, e.g., superheavy nuclei.
120465076
Beam optimization of helium injector for coupled RFQ-SFRFQ linac
Abstract The coupled RFQ–SFRFQ (CRS) cavity designed in Peking University is a new type linac that coupled radio frequency quadrupole (RFQ) and separated function radio frequency quadrupole (SFRFQ) structure into a single cavity. An upgraded helium injector for the CRS cavity consisting of a 2.45 GHz permanent magnet electron cyclotron resonance (ECR) ion source and a 1.16 m low energy beam transport (LEBT) has been constructed and tested. The beam conditions of the injector were carefully optimized to satisfy the requirements of the CRS linac, the corresponding control system and a two-dimension scanner code CRSv1.0 were developed for optimizing the beam transmission from LEBT section to the entrance of the CRS cavity. The beam transmission efficiency has reached to approximately 87.5% as well as the optimized operating parameters were obtained by means of the scanner code.
119112485
Multidimensionally constrained relativistic mean field model and applications in actinide and transfermium nuclei
We present some results of potential energy surfaces of actinide and transfermium nuclei from multidimensionally constrained relativistic mean field (MDC-RMF) models. Recently we developed multidimensionally constrained covariant density functional theories (MDC-CDFT), in which all shape degrees of freedom beta with even mu are allowed, and the functional can be one of the following four forms: the meson exchange or point-coupling nucleon interactions combined with the nonlinear or density-dependent couplings. In MDC-RMF models, the pairing correlations are treated with the BCS method. With MDC-RMF models, the potential energy surfaces of even-even actinide nuclei were investigated and the effect of triaxiality on the fission barriers in these nuclei was discussed. The nonaxial reflection-asymmetric beta(32) shape in some transfermium nuclei with N = 150, namely Cm-246, Cf-248, Fm-250 and No-252, were also studied.
92987620
Vertices, vortices & interacting surface operators
A bstractWe show that the vortex moduli space in non-abelian supersymmetric $ \mathcal{N} = \left( {{2},{2}} \right) $ gauge theories on the two dimensional plane with adjoint and anti-fundamental matter can be described as an holomorphic submanifold of the instanton moduli space in four dimensions. The vortex partition functions for these theories are computed via equivariant localization. We show that these coincide with the field theory limit of the topological vertex on the strip with boundary conditions corresponding to column diagrams. Moreover, we resum the field theory limit of the vertex partition functions in terms of generalized hypergeometric functions formulating their AGT dual description as interacting surface operators of simple type. Analogously we resum the topological open string amplitudes in terms of q-deformed generalized hypergeometric functions proving that they satisfy appropriate finite difference equations.
119171822
Hyperkähler metric and GMN ansatz on focus–focus fibrations
Abstract In this paper, we study the hyperkahler metric and practise GMN’s construction of hyperkahler metric on focus–focus fibrations. We explicitly compute the action–angle coordinates on the local model of focus–focus fibrations, and show its semi-global invariant should be harmonic to admit a compatible holomorphic 2-form. Then we study the canonical semi-flat metric on it. After the instanton correction, finally we are able to get a reconstruction of the generalized Ooguri–Vafa metric.