119533144
Excitation energy as a basic variable to control nuclear disassembly

Abstract: Thermodynamical features of Xe system is investigated as functions of temperature and freeze-out density in the frame of lattice gas model. The calculation shows different temperature dependence of physical observables at different freeze-out density. In this case, the critical temperature when the phase transition takes place depends on the freeze-out density. However, a unique critical excitation energy %and the same excitation reveals regardless of freeze-out density when the excitation energy is used as a variable instead of temperature. Moreover, the different behavior of other physical observables with temperature due to different ρf vanishes when excitation energy replaces temperature. It indicates that the excitation energy can be seen as a more basic quantity to control nuclear disassembly.
119972193
Measurements of total reaction cross sections for some light nuclei at intermediate energies
Measurements of the total reaction cross section for C12-16, N14-17, and O16-18 on carbon target at intermediate energies were performed on the Radioactive Ion Beam Line of the Heavy ion Research Facility in Lanzhou. A larger enhancement of sigma(R) for C-15 was observed than for its neighbors. Evidence for possible anomalous nuclear structure in C-15 was revealed in the analysis of the total reaction cross section in terms of the difference factor d.
53131397
Energy and system-size dependence of two- and four-particle $v_2$ measurements in heavy-ion collisions at RHIC and their implications on flow fluctuations and nonflow
We present STAR measurements of azimuthal anisotropy by means of the two- and four-particle cumulants $v_2$ ($v_2\{2\}$ and $v_2\{4\}$) for Au+Au and Cu+Cu collisions at center of mass energies $\sqrt{s_{_{\mathrm{NN}}}} = 62.4$ and 200 GeV. The difference between $v_2\{2\}^2$ and $v_2\{4\}^2$ is related to $v_{2}$ fluctuations ($\sigma_{v_2}$) and nonflow $(\delta_{2})$. We present an upper limit to $\sigma_{v_2}/v_{2}$. Following the assumption that eccentricity fluctuations $\sigma_{\epsilon}$ dominate $v_2$ fluctuations $\frac{\sigma_{v_2}}{v_2} \approx \frac{\sigma_{\epsilon}}{\epsilon}$ we deduce the nonflow implied for several models of eccentricity fluctuations that would be required for consistency with $v_2\{2\}$ and $v_2\{4\}$. We also present results on the ratio of $v_2$ to eccentricity.
123856190
Existence of a proton halo in Al-23 and its significance
Reaction cross section sigma(R) of proton-rich isotones (N = 10) near Al-23 and Al isotopes (Al23-28) on C target have been measured at intermediate energies around 30 MeV/nucleon. An abnormal increase of the experimental sigma(R) is observed for Al-23 and it suggests that there is an anomalously large matter rms radius in Al-23. Together with the very weakly binding of the last proton (S-p = 0.125 MeV), it indicates that there is a proton halo in Al-23. This conclusion is also supported by the difference factor d which is deduced from the measured and theoretical sigma(R) in the Glauber or Boltzmann-Uehling-Uhlenbeck model and is used for the manifest of halo phenomena. The theoretical calculation based,on the relativistic density dependent Hartree model shows that there is a proton halo when the last proton is in the 2s(1/2) orbit in Al-23. The significance of the proton halo in Al-23 is discussed.
125737170
Search for the top quark decaying to a charged Higgs boson in anti-p p collisions at S**2 (1/2) = 1.8-TeV
45929403
Sequential Decay Distortion of Goldhaber Model Widths for Spectator Fragments
The primary fragment momentum distributions from AMD-V can be described by a Gaussian shape characterized by a width σ. Figure 1: The three momentum widths, σ , σ , σ , as a removed from a nucleus that originally has A0 nucleons, a nucleus consisting of K nucleons will emerge. For this fragment of K nucleons, Goldhaber [1] showed that the momentum width, σ, could be expressed as: σ = σ0 sqrt [K(A0 K)/(A0 – 1)], where σ0, the reduced momentum width, is related to the intrinsic Fermi motion of a single nucleon, i.e.,: σ0 = sqrt (1/5)PF. Based upon electron scattering ments of Fermi momenta, σ is expected to be ≈ 112-116 MeV/c. However, σ ≈ MeV/c [2]. Some theoretical works [3] have attempted to explain this difference. However, the answers were still absent. In this work, we studied peripheral collisions of 200 MeV/nucleon Ar + Al with AMD-V model [4] and followed with the afterbuner (GEMINI) [5]. In the AMD-V model, initial width of the nucleon momentum distribution is ~ 105 MeV/c for Ar and ~ 101 MeV/c for Al. These values are less than expected from electron scattering measurements, but are still in a reasonable range. The fragment mass numbers and the three momentum widths, σPx, σPy, σPz, are plotted
53622530
Towards a non-relativistic holographic superfluid
We explore the phase structure of a holographic toy model of superfluid states in non-relativistic conformal field theories. At low background mass density, we found a familiar second-order transition to a superfluid phase at finite temperature. Increasing the chemical potential for the probe charge density drives this transition strongly first order as the low-temperature superfluid phase merges with a thermodynamically disfavored high-temperature condensed phase. At high background mass density, the system re-enters the normal phase as the temperature is lowered further, hinting at a zero-temperature quantum phase transition as the background density is varied. Given the unusual thermodynamics of the background black hole, however, it seems likely that the true ground state is another configuration altogether.
122901072
INTERACTING GENERALIZED CHAPLYGIN GAS MODEL WITH HOLOGRAPHIC DARK ENERGY
In this paper we consider the interacting generalized Chaplygin gas model as a unified scheme, in which the holographic dark energy as the dark energy component interacts with the cold dark matter with wdm = 0. Concretely, we mainly discuss the two kinds of interactions between the dark energy and dark matter, and give the evolution trajectories of density parameter and equation of state of dark energy as well as the decelerate parameter. By analysis, we show that in both cases of Q = 3bHρde and Q = 3bHρGCG, the evolution laws and the present values of Ωde, wde and q are compatible with the astronomical observations, but the effects of the coupling constant and holographic constant on them are completely different.
17840349
RESULTS FROM THE SLAC NLC TEST ACCELERATOR
The design for the Next Linear Collider (NLC) at SLAC is based on two 11.4 GHz linacs operating at an unloaded acceleration gradient of 50 MV/m increasing to 85 MV/m as the energy is increased from 1/2 TeV to 1 TeV in the center of mass[1]. During the past several years there has been tremendous progress on the development of 11.4 GHz (X-band) RF systems. These developments include klystrons which operate at the required power and pulse length, pulse compression systems that achieve a factor of four power multiplication and structures that are specially designed to reduce longrange wakefields. Together with these developments, we have constructed a 1/2 GeV test accelerator, the NLC Test Accelerator (NLCTA)[2]. The NLCTA will serve as a test bed as the design of the NLC is refined. In addition to testing the RF system, the NLCTA is designed to address many questions related to the dynamics of the beam during acceleration, in particular, multibunch beam-loading compensation and transverse beam break-up. In this paper we describe the NLCTA and present results from initial experiments.
14005761
The Next Linear Collider Test Accelerator
During the past several years, there has been tremendous progress on the development of the RF system and accelerating structures for a Next Linear Collider (NLC). Developments include high-power klystrons, RF pulse compression systems and damped/detuned accelerator structures to reduce wakefields. In order to integrate these separate development efforts into an actual X-band accelerator capable of accelerating the electron beams necessary for an NLC, we are building an NLC Test Accelerator (NLCTA). The goal of the NLCTA is to bring together all elements of the entire accelerating system by constructing and reliably operating an engineered model of a high-gradient linac suitable for the NLC. The NLCTA will serve as a testbed as the design of the NLC evolves. In addition to testing the RF acceleration system, the NLCTA is designed to address many questions related to the dynamics of the beam during acceleration. In this paper, we will report on the status of the design, component development, and construction of the NLC Test Accelerator.<<ETX>>
39289464
HLS Turn-by-Turn System and its Application
Measurement principles and analysis of Turn-by-Turn beam position monitor system at Hefei Light Source (HLS) are presented in this paper. In emphases, several typical applications are presented here, which include the commissioning of upgraded injection system on HLS storage, monitoring of transientν transientν transientν transientν transientν transientν transientν transientν transientν transientν and damping time of storage ring, beam instability in injection, as well as experiments of low frequency feedback system. Precise analyses of experimental results offer some conclusions, which are consistent with theoretical expectations. The system plays an important role in study of beam instability and improvement of machine performance.