We argue a factorization formula for semi-inclusive deep-inelastic scattering with hadrons in the current fragmentation region detected at low transverse momentum. To facilitate the factorization, we introduce the transverse-momentum dependent parton distributions and fragmentation functions with gauge links slightly off the light cone, and with soft-gluon radiations subtracted. We verify the factorization to one-loop order in perturbative quantum chromodynamics and argue that it is valid to all orders in perturbation theory.
We investigate coefficients in the Israel-Stewart's causal hydrodynamics and discuss the way to calculate them with a microscopic theory. Based on the hadro-molecular simulation based on an event generator URASiMA, we evaluate the coefficients for a hot and dense hadronic fluid.
Extensive plasma potential measurements have been carried out using a device developed at JYFL. In this article the main results of the measurements will be summarized. A new simulation code to study the electron heating is being developed. One objective of the code is to determine the change of the electron loss cone when the magnetic field component of the electromagnetic wave is taken into account along with the permittivity of the plasma. As a part of the work, accurate X-ray measurements have been initiated. A new plasma chamber based on the MMPS-concept (Modified MultiPole Structure) has successfully been constructed and tested with the JYFL 6.4GHz ECRIS. The results and conclusions will be presented elsewhere in these proceedings. In the same article, a new concept of ECRIS and first results will be presented. The active development work of evaporation ovens has been carried out in a joint European collaboration (ISIBHI). The objective of the task is to make the operation of the oven reliable at 2000 degrees C for several days. Both resistively and inductively heated ovens have been studied and further developed. The status of this work will be presented.
A radial sputter probe has been developed for the AECR-U as an additional method of producing metal ion beams. Negative voltage is applied to the probe to incite collisions with target atoms, thereby sputtering material into the plasma. The sputter probe is positioned through one of the 6 radial access slots between the permanent hexapole structure of the AECR-U. The probe position can be varied with respect to the inner edge of the hexapole magnet structure. Charge state distributions and peak beam intensities at bias voltages up to -5kV were obtained for gold samples at varying distances of the probe with respect to the plasma. For high charge states production the radial position with respect to the plasma was more sensitive than for the medium and lower charge states. For high charge state ion production the probe was optimized at a distance of 0.6cm inside the chamber wall (4.1cm from the center of the chamber). Stable beams with peak intensities of up to 28e mu A of AU(24+) and 1.42e mu A of Au41+ have been produced using the sputter probe technique. In addition, a solid state circuit under development by Scientific Solutions, Inc which provides a bandwidth up to 100MHz was used to drive the 14GHz klystron amplifier for the LBNL AECR-U ion source. Various broadband and discrete heating modes were tested and the results for high charge state ion production were compared with single frequency heating.
In the framework of the littlest Higgs(LH) model and the littlest Higgs model with T-parity(LHT), we investigate the single top production process e(-)gamma -> v(e)b (t) over bar, and calculate the corrections of these two models to the cross section of this process. We find that in the reasonable parameter space, the correction terms for the tree-level Wtb couplings coming from the LHT model can generate significantly corrections to the cross section of this process, which might be detected in the future high energy linear e(+)e(-) collider(ILC) experiments. However, the contributions of the new gauge boson W-H(+/-) predicted by the LH model to this process are very small.
GEM, which has rapidly been developed in recent years as a new type of gas detector, has advantages of high position resolution and counting rate with a wide potential application in particle physics and X-ray imaging and etc. One of the key techniques of GEM's development is the structure fabrication of the PI film for the detector, which is difficult to be done by the lithography process. In this paper we present the structure fabrication process of GEM's PI film, and the result of our work about it. We chose wet-etching and dry-etching to make the. structure holes of PI film, and find that wet-etching is better way to get perfect holes of GEM's PI film for future application with acceptable price. The successful fabrication of GEM's film structures is helpful to develop the domestic research of GEM detector. The performance of the GEM detector with such PI film still need more detail study.
D-0*(2308) and B-0* resonances are discussed with the molecular state assumption in the heavy chiral unitary approach. By studying the heavy baryon-pseudoscalar meson interaction, some molecular states are found. It is shown that there exists a bound DK state with a mass of about 2.312 +/- 0.041GeV in the strange sector, which can be identified as D (s0)*(2317). While in the non-strange sector, one wide-width state at about 2.1GeV and one narrow-width state at about 2.44GeV are found. These states should be associated with the D-0* state. Therefore, Do*(2308) cannot be explained by the assumption of the molecular structure only. Moreover, B-s0* and B-0* states are also predicted. A B(K) over bar bound state with the mass of 5.725 +/- 0.039GeV which can be assigned to the B-s0*(5725) state and B-0*(5536) and B-0*(5819) should be considered as the corresponding states in the non-strange sector.
In order to get high beam quality, a RF distribution system is required, with minimal phase drifts and errors in the BEPC II linac. The additional installation of phase reference cables and monitoring equipments and stable RF distribution for BEPC linac are finished. The master oscillator is chosen to offer RF signal with low phase noise and a stable phase distribution system is built to deliver RF signal to each klystron. A phase and amplitude detector is constructed to measure the phase precisely and an I Phi A unit is used for a phase shifter. Control software based on EPICS is used to connect all the units of the system, and a phasing method based on BPM is adopted to optimize the phase of each klystron. Now the phasing system is installed and tested in the klystron gallery of the BEPC II linac.
We investigate the properties of polarization vectors for gauge bosons, including their forms with arbitrary polarization direction in laboratory frame, their different sum rules, and the projection operators they constitute. Then by some examples, we illustrate techniques in calculating processes involving gauge bosons. Our discussion is beneficial for the understanding of the essence of gauge bosons.
Using the improved lattice Hamiltonian with massive Wilson quark and the variational method, we study the quark mass m, and the Wilson parameter r dependences of the quark condensate (psi psi) in the two-dimensional SU(N-C) lattice gauge theory. The numerical results show that when r is given, for N-C=2, 3, 4, 5, 6, 7,,the value of (psi psi)(sub) a/(gN(C)(3/2)) decreases as m(q) increases. For N-C > 3, when m(q) is small, (psi psi)(sub) a/(gN(C)(3/2)) is almost independent of r; when m(q) is large, (psi psi)(sub) a/(gN(C)(3/2)) increases with increasing r. Particularly, when m(q) -> 0, our numerical results agree very well with Zhitnitsky's analytical weak coupling result in the continuum, which implys that our numerical results in the case of m(q) not equal 0 are reliable.
We have derived the global band gaps for general two-dimensional (2D) photonic crystal microwave accelerating structures formed by square or triangular arrays of metal posts. A coordinate-space, finite-difference code was used to calculate the complete dispersion curves for the lattices. The fundamental and higher frequency global photonic band gaps were determined numerically. The structure formed by triangular arrays of metal posts with a missing rod at the center has advantages of higher-order-modes (HOM) suppression and main mode restriction under the condition of a/b < 0.2. The relationship between the RF properties and the geometrical parameters have been studied for the 9.37GHz photonic crystal accelerating structure. The R-s, Q, Rs/Q of the new structure may be comparable to the disk-loaded accelerating structure.
Using the home-made synchrotron radiation soft X-ray polarimeter based on multilayer elements, the polarization characteristics of the Beamline 3W1B have been measured at Beijing Synchrotron Radiation Facility (BSRF). This paper compares the measuring results of using polarizer with the results without the polarizer at 206eV. The degree of linear polarization without the polarizer is 0.585. However, the degree of linear polarization is up to 0.995, when the beam is polarized by multilayer optical elements.
The reaction rate of non-leptonic quark weak interaction and the bulk viscosity of quark matter in the magnetic field are investigated. The approximation method for calculating the reaction rate in a weak magnetic field is improved, the results of the reaction rate of non-leptonic process and the bulk viscosity of quark matter are given. It is shown that the relationship between the bulk viscosity and the temperature in the weak magnetic field case is the same as that in the zero magnetic field case, but the magnitude of bulk viscosity is affected by the strength of the magnetic field.
In this paper a new method to measure the lifetime of heavy hypernuclei is introduced, and the main device used in the measurement-fission fragment chamber (FFC)-is tested by a Cf-252 spontaneous source at Thomas Jefferson National Accelerator Facility (JLab). The chamber has a single-module timing resolution of similar to 163ps. Based on the timing resolution tested, our computer simulation predicts that the error of the measured lifetime is about 9.6ps.
We study the polarization effects of the top-quark on the t (t) over bar production cross sections at hadron colliders in the topcolor-assisted technicolor model. The MRS set A' parton distributions and the helicity projection operators methods are used in the calculation. It is shown that the polarization effects of the top quark are too small to produce enough identified signals at the Tevatron while they can be large enough to be detected at the LHC with reasonable values of the parameters. The polarization effects at the LHC can reach 16%, therefore, they provide feasible tests of the topcolor-assisted technicolor model.
Exotics belong to high multiplet of SU(3), so one can understand them by researching their non-exotic partners in the same multiplet. Here the possible 27-plet from flavor SU(3) symmetry are investigated. By fitting the mass spectrum and calculating the two-body partial hadronic decay widths of members, two set of 27-plet baryons with different parities are found. For the mass spectrum, all non-exotic members have their candidates in PDG except for a new A(1780). For the decay widths, the computing results show the approximate flavor SU(3) symmetry. The further analyzing and comparing with the results from other theoretical models can support the rationality of the 27-plet assignment.
The analysis of experimental nuclear charge radii R-c indicates that R-c deviates systematically from the A(1/3) law, i.e., R-c/A(1/3) gradually decreases with increasing A, whereas R-c/Z(1/3) remains almost a constant. This statement is also supported by the analysis of a large amount of experimental nulcear giant monopole resonance energy data E-x proportional to R-1. The deviation of nuclear charge radii from the A(1/3) law is basically caused by the isospin independence of A(1/3) law, and the isospin dependence has been partly included in Z(1/3) law. In the frame of nuclear shell model, a microscopic demonstration of the Z(1/3) law is given. The difference in the harmonic oscillator potential strength between proton and neutron (omega(p) and omega(n)) can be accounted for by the Z(1/3) law. Similar to Wigner's nuclear isobaric multiplet mass equation (IMME), a modified Z(1/3) law for nuclear charge radii is proposed.
The frequency map analysis (FMA) method is systematically applied to the lattice of the BEPC II storage ring for the first time in this paper. We compute characteristic parameters of the lattice with the Accelerator Toolbox (AT) code, in which the FMA method is imbedded, and compare the results with those of MAD and SAD codes. The lattices of the BEPC II collision and injection modes are analyzed and optimized using FMA with the RF cavity and radiation on. Both on- and off-momentum frequency maps are studied to have a complete picture of dynamics. The synchro-betatron resonance is found to have large effect on the beam dynamics.
In the present work, the structures of the excited positive/negative-parity yrast states of Tc-101 are discussed by using a projected shell model, and a band diagram calculated for the positive-parity yrast band is also shown in order to extract physics out of numerical results. In addition, the analysis of other three bands originated from 3/2(-)[301], 5/2(-)[303], and 1/2(+)[431] Nilsson states, respectively, is also performed in the framework of this model. Until recently, very little property about the N=52-54 intermediate nuclei in the Z similar to 42-44 region has been known. In order to understand these "transitional nuclei", we select the nucleus Tc-95 as an example. So in this work, we also present our investigation of the level structure in the Tc-95 nucleus.
To obtain a pure electron sample with high statistics,which is necessary for the asymmetry and cross section analysis for the small angle GDH experiment in JLab Hall-A,the information in shower and gas Cerenkov has been used in the particle identification.Due to the dependence of the kinematics,the PID cut and the corresponding efficiency have been optimized for different runs.
