118628184
Model-independent analysis for determining mass splittings of heavy baryons
We study the hyperfine mass differences of heavy hadrons in the heavy quark effect theory. The effects of one-gluon exchange interaction are considered for the heavy mesons and baryons. Based on the known experimental data, we predict the masses of some heavy baryons in a model-independent way.
118480874
Study of quark distribution amplitudes of 1S and 2S heavy quarkonium states
In this paper, the quark distribution amplitudes of 1S and 2S heavy quarkonium states are studied in terms of Gaussian-type wave functions. The transverse momenta p⊥ integrals of the formulae for the decay constant are performed analytically. Then the quark distribution amplitudes are obtained. In addition, the ξ-moments are also calculated. After fixing the relevant parameters appearing in the quark distribution amplitude, the curves of the quark distribution amplitude for 1S and 2S heavy quarkonium states are plotted. Finally, the numerical results of this approach are compared with the other theoretical predictions.
12196534
Mesonic form factors and the Isgur-Wise function on the light front
Within the light-front framework, form factors for P{r_arrow}P and P{r_arrow}V transitions (P denotes a pseudoscalar meson, V a vector meson) due to the valence-quark configuration are calculated directly in the entire physical range of momentum transfer. The behavior of the form factors in the infinite quark mass limit are examined to see if the requirements of heavy-quark symmetry are satisfied. We find that the Bauer-Stech-Wirbel-type light-front wave function fails to give a correct normalization for the Isgur-Wise function at zero recoil in P{r_arrow}V transition. Some of the P{r_arrow}V form factors are found to depend on the recoiling direction of the daughter mesons relative to their parents. Thus the inclusion of the nonvalence contribution arising from quark-pair creation is mandatory in order to ensure that the physical form factors are independent of the recoiling direction. The main feature of the nonvalence contribution is discussed. {copyright} {ital 1997} {ital The American Physical Society}
56298522
Operational experience of the insertion devices and expectation of the future superconducting wigglers at NSRRC
Since 1995, we have continuously installed five insertion devices (IDs) in the 1.5 GeV storage ring TLS at NSRRC. They include three undulators (U5, U9 and EPU5.6), one 1.8 Tesla wiggler (W20) and one 6 Tesla superconducting wavelength shifter (SWLS). All these five IDs are located in the long straight sections. The real time orbit correction and betatron tune compensation routine have been successfully operated. With these IDs, the machine emittance reduces substantially. We plan to install four more superconducting multi-pole wigglers (SMPWs), one in the long straight and three in the archromat sections. These devices therefore can offer more beam time for the hard X-ray community. The impacts of these IDs on the beam dynamics effects are reported in this paper.
54590931
MAGNETIC FIELD MEASUREMENT AND FINE-TUNING OF KICKERS
We have demonstrated an algorithm which promisingly can tune the pulse shape of current and magnetic field of kicker systems in-situ. This algorithm includes gap shimming of the ferrite magnets to adjust the pulse width of the excitation current and changing the resistance of the secondary coils to modify the pulse curvatures of each kicker. With the empirical formula derived from the systematic measurement on the magnetic field and the pulse current in laboratory, we can reduce the pulse-shape difference among the kicker magnets in the injection section of the storage ring, with no need to do anything on the pulsers and high voltage power suppliers. This approach can efficiently increase the injection efficiency which is demanding in the top-up injection mode adopted by many new facilities of synchrotron radiation.
211124417
MAGNET FIELD CROSSTALK EFFECT OF TPS STORAGE RING MAGNETS
The free space between magnets of Taiwan Photon Source (TPS) storage ring is slight, especially the space between the quadrupole and sextupole magnets. The minimum space between the yokes of quadrupole and sextupole magnets is about 150 mm, but the space between coils is only 10 mm. Accordingly, significant distortions of the magnetic field can have an impact on the performance of the machine. A comparison between two magnets and an individual magnet was simulated with TOSCA 3D. The crosstalk effect shows that the sextupole component normalized to the quadrupole field at x=0.03 m increases from 4 10 to 4 10 in the quadrupole magnet and the quadrupole component increases from 8 10 to 6 10 in the sextupole magnet. We discuss this crosstalk effect and how to decrease the effect with appropriate shielding. INTRODUCTION The TPS will be a highly brilliant synchrotron x-ray source for multidisciplinary experimental research in Taiwan. The most visible feature of the complex will be a 3~3.3GeV electron-storage ring having circumference 518 m. The TPS storage ring consists of approximately 460 magnetic elements, including 48 dipoles, 240 quadrupoles, 168 sextupoles etc [1]. The main parameters of the magnet design are listed in Table 1. Various of these magnets will be placed with an axial spacing between them smaller than in any other machine. The interference harmonics due to the proximity of magnets should be accurately known for ease of commissioning and reliable performance of the machine. CROSSTALK EFFECT BETWEEN QUADRUPOLE AND SEXTUPOLE The minimum distance between the yokes of quadrupole and sextupole magnets is about 150 mm, shown in Fig. 1. The beam is along the z-axis and the cross section of the magnet is in the xy plane. To compare the quadrupole gradient field (B1) with and without the sextupole, from a simulation we plot the vertical component of the field (By) as a function of z at x=40 mm and y=0 in three cases in Fig. 2. The red line results from only the quadrupole magnet in the space in the calculation of the field distribution; the green line is only from the sextupole magnet in the space, whereas the black line shows the two magnets in the space and both magnets powered. The field decreases to zero at z=236 mm between the two magnets, and the two magnets were separated by this point in this discussion. Figure 1: One tight case of the TPS quadrupole and sextupole magnets for study of the crosstalk effect. Table 1: Specifications of Storage-Ring Magnets Type Dipole Quadrupole Sextupole Quantity 48 192/48 168 Length (m) 1.1 0.3/0.6 0.25 Field strength(T,T/m,T/m) 1.191 17/15.63 478 Full gap (mm) 46 74 78 Good field region (mm) 40×30 ±30 ±32 Turns/pole 36 54/48 26 Conductor(mm) 16×16 8×8/9×9 8×8 Coolant diameter (mm) 7 4/4.5 4 Current (A) 640 188/187 135 Power/magnet (kW) 8.53 2.56/2.86 0.77 Water circuit number 4 4 2 Water velocity (m/s) 1.23 1.2/1.34 0.73 ___________________________________________ kuo.cy@nsrrc.org.tw Proceedings of IPAC’10, Kyoto, Japan MOPEB022 07 Accelerator Technology T09 Room-Temperature Magnets 325 0 100 200 300 400 500 600 700 800 900 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
119106630
Evidence for Aharony duality for orthogonal gauge groups
We study the Aharony duality for three dimensional $ \mathcal{N} = 2 $ supersymmetric gauge theories for orthogonal gauge groups with matters in vector representation. We provide the evidence for the duality by working out the partition function on S3 and the superconformal index, which show perfect agreement.
126172988
The Analysis of Hall probe mapping system for the combined function dipole magnet