10157335
Multi-deformed Configurations and Shape Coexistence for Superheavy Elements ∗
We use the considered axial deformed relativistic mean field theory to perform systematical calculations for Z = 112 and 104 isotopic chains with force parameters NL3, NL-SH and NL-Z2 sets. Three deformed chains (oblate, moderate prolate and super-deformed chain) are found for Z = 112 and 104 isotopic chains. It is found that there is a chain of super-deformed nuclei which can increase the stability of superheavy nuclei in the Z = 112 isotopic chain. Shape coexistence is found for Z = 112,104 isotopic chain and the position is defined. For moderate prolate deformed chains of Z = 112 and 104, there is shell closure at N = 184 for moderate prolate deformed chain. For oblate deformed chain of Z = 112, the shell closure appears around at N = 176. For super-deformed chains of Z = 112 and 104, the position of shell closure have strong parameter dependence. There is shell anomalism for oblate or superdeformed nuclei.
122405140
Effects of Delta Degrees of Freedom on Quark Condensate in Hot and Dense Matter
The relativistic mean-field theory is applied to study the quark condensate systematically in nuclear matter at zero and finite temperature in terms of the relative importance of delta degrees of freedom. Calculations have included the high-order contributions to quark condensate in nuclear medium due to the baryon-baryon interactions. Numerical results are presented for the nuclear density up to five times larger than the normal density and temperature up to 120 MeV. It is found that the delta resonance in nuclear matter can cause substantial decreases to in-medium quark condensate.
124229961
A light-cone QCD inspired effective Hamiltonian model for pseudoscalar and scalar mesons
Considering the one-gluon exchange interaction and phenomenological quark confinement potential, an improved light-cone effective Hamiltonian for mesons and the corresponding radial mass eigen equations in angular momentum representation is obtained. Solving the J = 0 eigen equations numerically and using a set of adjustable parameters, the obtained solutions for ground states and radial excited states can simultaneously describe both pseudoscalar and scalar flavour-off-diagonal mesons. Some radial excited states are also predicted and wait for experimental test. More results for the vector and axial vector mesons are expected.
119255736
Determining Nuclear Form factor for Detection of Dark Matter in Relativistic Mean Field Theory
In this work, we derive the nuclear form factor for the spin-independent collision between the WIMPs and nucleus in terms of the relativistic mean field (RMF) theory. Comparison with the traditional form factors which are commonly used in literature is given and it is found that our results are slightly above that of the 2PF model by 4% to 8%, but deviate from the Helm form factor by 15% to 25% for the whole recoil energy spectrum of 0 ~ 100 keV. Moreover, taking Xe and Ge as examples, we show the dependence of the form factor on the recoil energy.
122969926
K− Nucleus Elastic Scattering and Momentum-Dependent Optical Potentials
The K− nucleus differential elastic scattering cross section for 12C and 40Ca at is calculated with three momentum-dependent optical potential models, which are density-dependent, relativistic mean field, and hybrid model, respectively. It is found that the forms of momentum-dependent optical potential models proposed by us are reasonable and gain success in the calculations and the momentum-dependent hybrid model is the best model for the K− nucleus elastic scattering.
123801339
Finite volume effect of baryons in strange hadronic matter
The finite volume effect of baryons in strange hadronic mai;ter (SHM) is studied within the framework of relativistic mean-field theory. As this effect is concerned, the saturation density of SHM turns lower, and the binding energy per baryon decreases. Its influence to the compression modulus of SHM is also discussed.
118401964
Stochastic resonance with matched filtering
Along with the development of interferometric gravitational wave detector, we enter into an epoch of gravitational wave astronomy, which will open a brand new window for astrophysics to observe our universe. Almost all of the data analysis methods in gravitational wave detection are based on matched filtering. Gravitational wave detection is a typical example of weak signal detection, and this weak signal is buried in strong instrument noise. So it seems attractable if we can take advantage of stochastic resonance. But unfortunately, almost all of the stochastic resonance theory is based on Fourier transformation and has no relation to matched filtering. In this paper we try to relate stochastic resonance to matched filtering. Our results show that stochastic resonance can indeed be combined with matched filtering for both periodic and non-periodic input signal. This encouraging result will be the first step to apply stochastic resonance to matched filtering in gravitational wave detection. In addition, based on matched filtering, we firstly proposed a novel measurement method for stochastic resonance which is valid for both periodic and non-periodic driven signal.
569169
Multitemperature Blackbody Spectrum of a Thin Accretion Disk around a Kerr Black Hole: Model Computations and Comparison with Observations
We use a ray-tracing technique to compute the observed spectrum of a thin accretion disk around a Kerr black hole. We include all relativistic effects such as frame-dragging, Doppler boost, gravitational redshift, and bending of light by the gravity of the black hole. We also include self-irradiation of the disk as a result of light deflection. Assuming that the disk emission is locally blackbody, we show how the observed spectrum depends on the spin of the black hole, the inclination of the disk, and the torque at the inner edge of the disk. We find that the effect of a nonzero torque on the spectrum can, to a good approximation, be absorbed into a zero-torque model by adjusting the mass accretion rate and the normalization. We describe a computer model, called KERRBB, which we have developed for fitting the spectra of black hole X-ray binaries. Using KERRBB within the X-ray data reduction package XSPEC, and assuming a spectral hardening factor fcol = 1.7, we analyze the spectra of three black hole X-ray binaries: 4U 1543-47, XTE J1550-564, and GRO J1655-40. We estimate the spin parameters of the black holes in 4U 1543-47 and GRO J1655-40 to be a/M ~ 0.6 and ~0.6-0.7, respectively. If fcol ~ 1.5-1.6, as in a recent study, then we find a/M ~ 0.7-0.8 and ~0.8-0.9, respectively. These estimates are subject to additional uncertainties in the assumed black hole masses, distances, and disk inclinations.
122993825
Field measurement of PEP-II LER dipoles and quadrupoles at IHEP
The field measurement of 209 dipoles and 320 quadrupoles for PEP-II LER will be finished at IHEP in June 1997. This paper covers the details of the magnetic measurement devices developed to measure these magnets as well as the results of the measurements.
11909154
The X‐ray transient 080109 in NGC 2770: an X‐ray flash associated with a normal core‐collapse supernova
Although it is generally thought that long-duration gamma-ray bursts (LGRBs) are associated with core-collapse supernovae (SNe), so far only four pairs of GRBs and SNe with firmly established connection have been found. All the four GRB-SNe belong to special class of Type Ic – called the broad-lined SNe indicative of a large explosion energy, suggesting that only a small fraction of SNe Ibc have GRBs associated with them. This scheme has been refreshed by the discovery of a bright X-ray transient in NGC 2770 on 2008 January 9, which was followed by a rather normal Type Ib SN 2008D. In this paper, I argue that the transient 080109 is an X-ray flash (XRF, the soft version of a GRB) because of the following evidence. (1) The transient cannot be interpreted as a SN shock breakout event. (2) The GRB X-ray flare interpretation is not supported by the high-energy observation. I then show that XRF 080109 satisfies the well-known relation between the isotropic-equivalent energy and the peak spectral energy for LGRBs, which highly strengthens the XRF interpretation. Finally, I point out that the peak spectral energy of XRF 080109 and the maximum bolometric luminosity of SN 2008D agree with the E γ, peak–LSN,max relationship of Li, strengthening the validity of the relationship. I speculate that events like XRF 080109 may occur at a rate comparable to SNe Ibc, and a soft X-ray telescope devoted to surveying for nearby X-ray flares will be very fruitful in discovering them.
36263241
New optimization methods for converging perturbative series with a field cutoff
We take advantage of the fact that in lambda phi ^4 problems a large field cutoff phi_max makes perturbative series converge toward values exponentially close to the exact values, to make optimal choices of phi_max. For perturbative series terminated at even order, it is in principle possible to adjust phi_max in order to obtain the exact result. For perturbative series terminated at odd order, the error can only be minimized. It is however possible to introduce a mass shift in order to obtain the exact result. We discuss weak and strong coupling methods to determine the unknown parameters. The numerical calculations in this article have been performed with a simple integral with one variable. We give arguments indicating that the qualitative features observed should extend to quantum mechanics and quantum field theory. We found that optimization at even order is more efficient that at odd order. We compare our methods with the linear delta-expansion (LDE) (combined with the principle of minimal sensitivity) which provides an upper envelope of for the accuracy curves of various Pade and Pade-Borel approximants. Our optimization method performs better than the LDE at strong and intermediate coupling, but not at weak coupling where it appears less robust and subject to further improvements. We also show that it is possible to fix the arbitrary parameter appearing in the LDE using the strong coupling expansion, in order to get accuracies comparable to ours.