118997767
Forward Charge Flow in Hadronic J/psi Production
179453560
NEW BES AND CLEO RESULTS
123211493
Exploring the feasibility of a separated function RFQ with mini-vane structure
The accelerating field in the conventional RFQ is originated by the surface modulation of the quadruple electrodes. However, the axial accelerating field generated in this way is quite limited. To enhance the energy gain as well as the focusing power, a post-RFQ accelerating structure called separated function RFQ (SFRFQ) was proposed (Progr. Nat. Sci. 12(1) (2002) 23), and its feasibility has been explored (Chin. Phys. 51(6) (2002)). The RF accelerating field in the SFRFQ structure mainly occurs at gaps between periodical cells, while the electrical quadruple field inside the cells provides the transverse focusing. It turns out that the overall performance can be improved considerably, comparing with that of conventional RFQ. The preliminary results of calculation and model measurements are presented and discussed in the paper.
121624088
GENERAL REVIEW OF BES PHYSICS, ACHIEVEMENT AND FUTURE
A general review of BES physics results are given. New results from BES on J/ψ, ψ(2S) and ψ(3770) decays are presented. Enhancement of the mass spectrum at the threshold is observed in the decay of J/ψ to . Analyzes of sigma and kappa signals are reported in J/ψ to ωπ+π- and J/ψ to respectively. Results of new ψ(2S) decay channels are reported and compared with 12% rule. Some results from ψ(3770) scanning and D decays are reported. The status of BEPCII/BESIII project is briefly reported.
39938475
Experimental Study of Long Coupled Helix Resonator
Experimental tests of a coupled normal temperature low a helix resonator with six-half-wavelength are described. The frequency shift and dynamic instability of the resonator are studied experimentally. The mechanical vibration caused by ponderomotive effect has been controlled. This resonator can run stably at a RF power of 50 KW , frequency of 27 MHz, duty factor of 1/6, and the maximum voltage gain is more than 1.1 MV. Some measures have been taken to increase the stability of the helix. The resonator tested is a model for heavy ion booster following a small van de graff accelerator.
118124145
BEPCII/BESIII Upgrade and the Prospective Physics
The Status of BEPCII/BESIII upgrade is described, BEPCII is designed to reach a luminosity of $10^{33}/cm^{-2}s^{-1}$ at c. m. energy of 3.89GeV, and BESIII detector is fully rebuilt. The project is on track and is progressing well. The machine and detector are expected to commission together at the late half of 2007, and start to take some engineer run end of 2007 or beginning of 2008.
18978953
Holographic RG flow and the quantum effective action
The calculation of the full (renormalized) holographic action is undertaken in general Einstein-scalar theories. The appropriate formalism is developed and the renormalized effective action is calculated up to two derivatives in the metric and scalar operators. The holographic RG equations involve a generalized Ricci flow for the space-time metric as well as the standard β-function flow for scalar operators. Several examples are analyzed and the effective action is calculated. A set of conserved quantities of the holographic flow is found, whose interpretation is not yet understood.
14733840
Monte Carlo Simulations of Type Ia Supernova Observations in Supernova Surveys
We have performed Monte Carlo simulations of Type Ia supernova (SN Ia) surveys to quantify their efficiency in discovering peculiar overluminous and underluminous SNe Ia. We determined how the type of survey (magnitude-limited, distance-limited, or a hybrid) and its characteristics (observation frequency and detection limit) affect the discovery of peculiar SNe Ia. We find that there are strong biases against the discovery of peculiar SNe Ia introduced by at least four observational effects: the Malmquist bias, the age of the SN Ia at the time of its discovery, the shape of its light curve, and its degree of extinction. Surveys with low observation frequency (less than once per 10 days) tend to discover SNe Ia that are too old for observers to easily recognize their peculiarity. Subluminous SNe Ia are underrepresented in magnitude-limited surveys because they can only be found within a small volume and they remain above the detection limit for less time. Conversely, overluminous SNe Ia are more easily found in magnitude-limited surveys, although their likely association with dusty regions reduces the volume in which they can be discovered. The unbiased rate of peculiar SNe Ia can be recovered only in distance-limited surveys with high observation frequencies and with detection limits that are fainter than the peak magnitude of a subluminous SN Ia in the farthest potential host.
123935567
Demonstration of a widely-tunable and fully-coherent high-gain harmonic-generation free-electron laser
Free-electron lasers (FELs) are fourth-generation light sources that deliver extremely high intensity, ultrashort light pulses over a broad wavelength range from far-infrared to hard x ray. FELs based on the self-amplified spontaneous emission principle have been successfully operated with ultrahigh brightness and a broad wavelengths tuning range with good transverse coherence but poor temporal coherence. In contrast, the laser-seeded FELs have provided full coherence but at selected central wavelengths, usually the harmonics of the laser seeds, with relatively narrower tuning range. We report the experimental demonstration of a high-gain harmonic-generation (HGHG) FEL that is continuously tunable over a wide range using the combination of optical parametrical amplification, variable-gap undulator, and harmonic selection, where the temporal coherence is preserved as confirmed with the Michelson interferometry. In order to achieve higher photon energies, the first try of cascaded HGHG with a fresh-bunch technique is also made at the Shanghai Deep Ultraviolet Free-electron Laser test facility. DOI: 10.1103/PhysRevSTAB.16.020704
119491399
SN 2005bf: a possible transition event between type Ib/c supernovae and gamma-ray bursts
We present ugriBV photometry and optical spectroscopy of the Type Ib/Ic SN 2005bf covering the first �100 days following discovery. The ugBV light curves displayed an unprecedented morphology among Type Ib/Ic supernovae, with an initial maximum some 2 weeks after discovery, and a second, main maximum about 25 days after that. The bolometric light curve indicates that SN 2005bf was a remarkably luminous event, radiating at least 6.3×10 42 erg s −1 at maximum light, and a total of 2.1 × 10 49 erg during the first 75 days after the explosion. Spectroscopically, SN 2005bf underwent a unique transformation
10700932
Non-supersymmetric attractor flow in symmetric spaces
We derive extremal black hole solutions for a variety of four dimensional models which, after Kaluza-Klein reduction, admit a description in terms of 3D gravity coupled to a sigma model with symmetric target space. The solutions are in correspondence with certain nilpotent generators of the isometry group. In particular, we provide the exact solution for a non-BPS black hole with generic charges and asymptotic moduli in = 2 supergravity coupled to one vector multiplet. Multi-centered solutions can also be generated with this technique. It is shown that the non-supersymmetric solutions lack the intricate moduli space of bound configurations that are typical of the supersymmetric case.