118620211
Relativistic Correction to Color Octet J/psi Production at Hadron Colliders
The relativistic corrections to the color-octet $J/\psi$ hadroproduction at the Tevatron and LHC are calculated up to $\mathcal{O}(v^2)$ in nonrelativistic QCD factorization frame. The short distance coefficients are obtained by matching full QCD with NRQCD results for the partonic subprocess $g+g\to J/\psi ({}^1S_0^{[8]},{}^3S_1^{[8]}, {}^3P_J^{[8]})+g$, $q+\bar{q}\to J/\psi ({}^1S_0^{[8]},{}^3S_1^{[8]}, {}^3P_J^{[8]})+g$ and $g+q({\bar{q}})\to J/\psi ({}^1S_0^{[8]},{}^3S_1^{[8]}, {}^3P_J^{[8]})+q({\bar{q}})$. The short distance coefficient ratios of relativistic correction to leading order for color-octet states ${^1}S_{0}^{[8]}$, ${^3}S_{1}^{[8]}$, and ${^3}P_{J}^{[8]}$ at large $p_T$ are approximately -5/6, -11/6, and -31/30, respectively, for each subprocess, and it is 1/6 for color-singlet state ${^3}S_{1}^{[1]}$. If the higher order long distance matrix elements are estimated through velocity scaling rule with adopting $v^2=0.23$ and the lower order long distance matrix elements are fixed, the leading order cross sections of color-octet states are reduced by about a factor of $20\sim40%$ at large $p_T$ at both the Tevatron and the LHC. Comparing with QCD radiative corrections to color-octet states, relativistic correction is ignored along with $p_T$ increasing. Using long distance matrix elements extracted from the fit to $J/\psi$ production at the Tevatron, we can find the unpolarization cross sections of $J/\psi$ production at the LHC taking into account both QCD and relativistic corrections are changed by about $20\sim50%$ of that considering only QCD corrections. These results indicate that relativistic corrections may play an important role in $J/\psi$ production at the Tevatron and the LHC.
124097178
Neutrino Oscillation and CP Violation in Low Energy Phenomenology of an SUSY Model
Neutrino oscillation and CP violation effects are discussed in an SUSY model proposed in Ref. [1]. The oscillation probabilities expected by this model in short baseline and long baseline neutrino oscillation experiments are calculated. The small conversion probability is predicted for all or oscillations. However, large long baseline oscillation probability is predicted, which could be observed in future long baseline experiments.
119479887
S-D mixing and ψ (3770) production in e + e − annihilation and B decay and its radiative transitions
The large decay rate observed by Belle for ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\psi}(3770){K}^{+}$, which is comparable to ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\psi}(3686){K}^{+}$, might indicate either an unexpectedly large S-D mixing angle $|\ensuremath{\theta}|\ensuremath{\approx}{40}^{\ifmmode^\circ\else\textdegree\fi{}}$ or the leading role of the color-octet mechanism in D-wave charmonium production in $B$ decay. By calculating the production rate of $\ensuremath{\psi}(3770)$ in the continuum ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at $\sqrt{s}=10.6\text{ }\text{ }\mathrm{G}\mathrm{e}\mathrm{V}$ with these two possible approaches (i.e., the large S-D mixing and the color-octet mechanism), we show that the measurement for this process at Belle and BABAR may provide a clear cut clarification for the two approaches. In addition, the radiative E1 transition ratio $\ensuremath{\Gamma}[\ensuremath{\psi}(3770)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{c2}]/\ensuremath{\Gamma}[\ensuremath{\psi}(3770)\ensuremath{\rightarrow}\ensuremath{\gamma}{\ensuremath{\chi}}_{c1}]$ may dramatically change from $\ensuremath{\sim}$ 0.04 (for $\ensuremath{\theta}\ensuremath{\approx}{0}^{\ifmmode^\circ\else\textdegree\fi{}}$) to $\ensuremath{\sim}200$ (for $\ensuremath{\theta}\ensuremath{\approx}\ensuremath{-}{40}^{\ifmmode^\circ\else\textdegree\fi{}}$) due to the large S-D interference effect, thus the E1 transition measurement of $\ensuremath{\psi}(3770)$ at Beijing Spectrometer and CLEO-c will also be very useful in clarifying this issue.
54875662
Power factor simulation of focus quadrupole DC power supply of white circuit system with MATLAB simulink
The focus quadrupole DC power supply used at white circuit system of booster ring of Synchrotron Radiation Research Center (SRRC) is a 19.2kW unit, but an AC power source to measure the power factor of such a power supply with built-in power factor measuring function is very expensive. Power factor simulation of this power supply with MATLAB Simulink software is economic and the simulated results may be used to find some efficient ways to correct this parameter if necessary. The results from the simulation model will be compared with the results of power factor monitored from direct measurement on AC mains. The model of quadrupole DC power supply is constructed and provided for better understanding for further modification.
52259853
Low cost concepts to reduce the voltage ripple of a DC power supply
If the gain of current feedback is low, the short term stability of a magnet power supply will be affected by a soft power line. Typically, the step-change and the imbalance of the three phase power line cause the most serious voltage ripple. Usually, voltage feedback with a coupling transformer is considered to reduce the voltage ripple. However, for the high current power supply, the space and cooling problem of the coupling transformer become inconvenient. In this paper, we suggest to use a toroidal core with a compensation winding, working like a DCCT, as the coupling transformer. Then, a high speed detector of the AC line level is developed. It restricts the voltage ripple passing to the coupling transformer. These methods have the advantage of small size, low power consumption and low cost.<<ETX>>
37596587
ZERO VOLTAGE SWITCHING OF TWO-SWITCH FLYBACK- FORWARD CONVERTER
The traditional pulse-width-modulated flyback converter power switch has serious electromagnetic interference (EMI) and lower conversion efficiencies problems due to the hard-switching operations. This paper produces a zero voltage switching of flyback-forward converter with an active-clamp circuit, the traditional pulse-width-modulated flyback converter with a active clamp circuit to achieve zero-voltage-switching (ZVS) at both main and auxiliary switches, the active-clamp circuit can reduce most of switching loss and voltage spikes across the switches and improve the overall efficiency of the converter. The theoretical analysis of soft switching flyback-forward converter with an active-clamp circuit is verified exactly by a prototype of 50W with 100V input voltage, 5V output voltage and 30kHz operated frequency.
55337938
DESIGN AND MODELING OF THE STEP DOWN PIEZO TRANSFORMER
The energy conversion and the step down voltage waveform of the piezo transformer are required to achieve optimal working condition of the resonant frequency. To meet this requirement, a reliable and precise instrument is needed to scan the resonant point of the piezo transformer such that its output power performance can meet the required specification. In this paper, the design and model of a new step down piezo transformer deployed in NSRRC is described. This step down piezo transformer is capable of delivering energy conversion with high efficiency performance, which is better than traditional transformer, and the voltage transfer ratio is correct. Using the simulation circuit model to develop driver circuit of it is also included in the design of this new step down transformer. It has been tested and proven to be working well in power conversion with excellent efficiency and reliability.
45531082
PIEZOELECTRIC TRANSFORMER BASED CONTINUOUS- CONDUCTION-MODE VOLTAGE SOURCE CHARGE-PUMP POWER FACTOR CORRECTION ELECTRONIC BALLAST *
This paper presents the piezoelectric transformer (PT) based continuous-conduction-mode (CCM) voltage source (VS) charge-pump (CP) power factor correction (PFC) electronic ballast. By replacing L-C resonant tank and transformer in the conventional CCM VS CP-PFC electronic ballast with PT, the cost and volume can be reduced. The experimental results show that the electronic ballast using PT achieve high power factor and the switches can be operated under zero-voltageswitching condition.