625243
CosmoMC Installation and Running Guidelines
CosmoMC is a Fortran 95 Markov-Chain Monte-Carlo (MCMC) engine to explore the cosmological parameter space, plus a Python suite for plotting and presenting results (see this http URL). This document describes the installation of the CosmoMC on a Linux system (Ubuntu 14.04.1 LTS 64-bit version). It is written for those who want to use it in their scientific research but without much training on Linux and the program. Besides a step-by-step installation guide, we also give a brief introduction of how to run the program on both a desktop and a cluster. We share our way to generate the plots that are commonly used in the references of cosmology. For more information, one can refer to the CosmoCoffee forum (this http URL) or contact the authors of this document. Questions and comments would be much appreciated.
118497313
Inflation in de Sitter spacetime and CMB large scale anomaly
The influence of cosmological constant-type dark energy in the early universe is investigated. This is accommodated by a new dispersion relation in de Sitter spacetime. We perform a global fit to explore the cosmological parameter space by using the CosmoMC package with the recently released Planck TT and WMAP polarization datasets. Using the results from the global fit, we compute a new CMB temperature temperature (TT) spectrum. The obtained TT spectrum has lower power compared with that based on the ACDM model at large scales.
123863059
Design and simulations for the detector based on DSSSD
The present paper describes the design and simulation results of a position-sensitive charged particle detector based on the Double Sided Silicon Strip Detector (DSSSD). Also, the characteristics of the DSSSD and its testing result were are discussed. With the application of the DSSSD, the position-sensitive charged particle detector can not only give particle flux and energy spectra information and identify different types of charged particles, but also measure the location and angle of incident particles. As the detector can make multiparameter measurements of charged particles, it is widely used in space detection and exploration missions, such as charged particle detection related to earthquakes, space environment monitoring and solar activity inspection.
123742975
Design and performance study of the LEPD silicon tracker onboard the CSES satellite
The low energy particle detector (LEPD) is one of the main payloads onboard the China seismic electromagnetic satellite (CSES). The detector is designed to ascertain space electrons (0.1–10 MeV) and protons (2–50 MeV). It has the capability of identifying the electrons and protons, to measure the energy spectrum and the incident angle of the particles. The LEPD is made up of a silicon tracker system, a CsI (Tl) mini-calorimeter, an anti-coincidence system made by plastic scintillator, as well as electronics and a data acquisition system (DAQ). The tracker is also a kind of ΔE-E telescope; it consists of two layers of double-sided silicon strip detectors (DSSD). The signals emerging from the silicon tracker can be read out by two pieces of application specific integrated circuit (ASIC), which also can generate an event trigger for the LEPD. The functions of the DSSD system in the LEPD for charged particles were tested by 241Am @5.486 MeV α particles. The results show that the DSSD system works well, and has high performance to detect charged particles and measure the position of incident particles.
124682883
A geometric factor calculation method based on the isotropic flux assumption
One of the instruments onboard the China Seismic Electromagnetic Satellite (CSES) is the Low Energy Particle Detector (LEPD). The primary objective of LEPD is to provide measurements of the fluxes, energy spectra and pitch angles of 100 keV to 10 MeV electrons and protons from 2 to 50 MeV in the Earth's magnetosphere. The geometric factor is one of the principle parameters of a detector, which converts the physical quantity count rate to the particle quantity-flux. In this paper, we calculated the geometric factor of LEPD via computer modeling of an isotropic radiation environment. It was first demonstrated that the radiation intensity related should obey a cosine-law, then a general sampling method of generating this distribution via CPS of GEANT4 was explained. Furthermore, combined with flux normalization, a comparison of the geometric factor calculation of a set of 2-layer detectors with different shapes (cylinder, truncated cone and rectangle) was performed. Results show a generally good agreement between simulation and analytical calculations for the cylinder and truncated cone detectors, and the result of the rectangular one, for which there is no accurate analytical formula, is consistent with the previous simulated results by others. As a practical instance of the 2-layer rectangle detector, the geometric factor of LEPD is 10.336 +/- 0.036 cm(2).sr for 10 MeV proton and 8.211 +/- 0.032 cm(2).sr for 8 MeV electron.
14119561
Light 1−+ exotics: Molecular resonances
Abstract Highlights in the search for nonconventional (non- q q ¯ ) meson states are the π 1 ( 1400 ) and π 1 ( 1600 ) exotic candidates. Should they exist, mounting theoretical arguments suggest that they are tetraquark molecular resonances excitable by meson rescattering. We report a new tetraquark calculation within a model field theory approximation to Quantum Chromodynamics in the Coulomb gauge supporting this conjecture. We also strengthen this claim by consistently contrasting results with exotic state predictions for hybrid ( q q ¯ g ) mesons within the same theoretical framework. Our findings confirm that molecular-like configurations involving two color singlets (a resonance, not a bound state) are clearly favored over hybrid or color-exotic tetraquark meson ( q q ¯ q q ¯ atoms) formation. Finally, to assist needed further experimental searches we document a useful off-plane correlator for establishing the structure of these exotic systems along with similar, but anticipated much narrower, states that should exist in the charmonium and bottomonium spectra.
125685455
First observation of J / psi and psi(2S) decaying to n K0(S) anti-Lambda + c.c
123878919
Partial wave analysis of J/psi ---> p anti-p pi0
Using a sample of 58 million J/{psi} events collected with the BESII detector at the BEPC, more than 100 000 J/{psi}{yields}pp{pi}{sup 0} events are selected, and a detailed partial wave analysis is performed. The branching fraction is determined to be Br(J/{psi}{yields}pp{pi}{sup 0})=(1.33{+-}0.02{+-}0.11)x10{sup -3}. A long-sought missing N*, first observed in J/{psi}{yields}pn{pi}{sup -}, is observed in this decay too, with mass and width of 2040{sub -4}{sup +3}{+-}25 MeV/c{sup 2} and 230{sub -8}{sup +8}{+-}52 MeV/c{sup 2}, respectively. Its spin-parity favors (3/2){sup +}. The masses, widths, and spin parities of other N* states are obtained as well.
119728121
Coulomb instability of hot nuclei in a chiral symmetry model
A chiral symmetry model for nuclear matter is extended to finite temperature and then used to study the Coulomb instability of hot nuclei. The role of the rho meson degree of freedom is discussed. The calculated limiting temperature is compared with the results obtained from other theories and experiments. [S0556-2813(99)05006-2].
119118321
A MATHEMATICAL REVIEW ON THE MULTIPLE-SOLUTION PROBLEM
The recent multiple-solution problem in extracting physics information from a fit to the experimental data in high energy physics is reviewed from a mathematical viewpoint. All these multiple solutions were previously found via a fit process, while in this paper we prove that if the sum of two coherent Breit–Wigner functions is used to fit the measured distribution, there should be two and only two nontrivial solutions, and they are related to each other by analytical formulae. For real experimental measurements in more complicated situations, we also provide a numerical method to derive the other solution from the already obtained one. The excellent consistency between the exact solution obtained this way and the fit process justifies the method. From our results it is clear that the physics interpretation should be very different depending on which solution is selected. So we suggest that all the experimental measurements with potential multiple solutions be re-analyzed to find the other solution because the result is not complete if only one solution is reported.