124798718
Recent results from BESIII
53333106
Recent results on strangeness, charm and beauty production at HERA
Based on the data collected with the H1 and ZEUS detectors at HERA, recent results on strangeness, charm and beauty production in ep collision are presented.
126424369
η and η' physics at BESIII
123432115
Progress in light hadron spectroscopy at BESIII
Based on the 225 million J / ψ events and 106 million ψ ′ events taken at the BESIII detector, the recent results on light hadron spectroscopy are presented, including the partial wave analysis of J / ψ → γ p p ¯ and ψ ′ → p p ¯ η , confirmation of X(1835) and observation of two new resonances in J / ψ → γ π + π − η ′ , observation of a new resonance X(1870) in J / ψ → ω π + π − η and the first observation of isospin-violating decay mode of η ( 1405 ) → f 0 ( 980 ) π 0 .
11750018
Measurement of the charm fragmentation into D* mesons at HERA
The charm fragmentation function has been measured with the H1 and ZEUS detectors at HERA in the deep inelastic scattering and photoproduction regimes. The measured function has been compared to different fragmentation models implemented in leading-logarithm Monte Carlo simulations and next-to-leading-order calculations.
125315096
eta(c) physics at BES III
An introduction for eta(c) physics research is presented in this paper, which shows that the mechanism of eta(c) decays can't be. well described by current theoretical models and detailed experimental measurements need to be done with larger eta(c) sample. Based on the expected J/psi and psi' events taken with the planed BES III detector in one year, the eta(c) physics researches are discussed extensively, including the measurements of branching fractions of different final states, the search for new decay, modes, precision measurements of mass and width, and the search for rare decays. At last, the study of eta'(c) decays is also discussed briefly.
121358236
Emittance balancing technique for the resonant slow extraction from a synchrotron
A new method is proposed to produce identical beam emittances in the transverse phase planes from a severely asymmetric beam extracted from a slow-cycling synchrotron. This is important to obtain a good beam distribution at the irradiation spot when the spot scanning method is used for the treatment in hadron therapy. The method makes use of the beam rotation effect either by a solenoid or by a rotational quadrupole section, referred to as rotator, to produce identical emittances in the two transverse phase planes. It is also helpful for the stabilization of the beam spot at the irradiation point. Simulation studies with an artificially generated beam have been carried out to prove the principle. The method is not only applicable to fixed treatment nozzles but also to rotational gantry nozzles. Both a solenoid and a section of quadrupole rotator can be used, with the former being ideal for proton gantries and the latter for fixed carbon nozzles. There is a practical limit in using room-temperature solenoid due to the high beam rigidity in the case of a carbon beam, for which a superconducting solenoid has to be used. The comparison with other methods and the practical applications of the method are also presented.
209441918
BRIEF OVERVIEW OF PARTICLE ACCELERATORS IN CHINA
A brief overview of the main particle accelerators in China is given. New projects in the near future are also simply described.
118222135
QCD Approach to B ---> D pi Decays and CP Violation
The branching ratios and CP violations of the B -> D pi decays, including both the color-allowed and the color-suppressed modes, are investigated in detail within QCD framework by considering all diagrams that lead to three effective currents of two quarks. An intrinsic mass scale as a dynamical gluon mass is introduced to treat the infrared divergence caused by the soft collinear approximation in the endpoint regions, and the Cutkosky rule is adopted to deal with a physical-region singularity of the on mass-shell quark propagators. When the dynamical gluon mass mu(g) is regarded as a universal scale, it is extracted to be around mu(g) = 440 MeV from one of the well-measured B -> D pi decay modes. The resulting predictions for all branching ratios are in agreement with the current experimental measurements. As these decays have no penguin contributions, there are no direct CP asymmetries. Due to interference between the Cabibbo-suppressed and the Cabibbo-favored amplitudes, mixing-induced CP violations are predicted in the B -> D-+/-pi(-/+) decays to be consistent with the experimental data at 1-sigma level. More precise measurements will be helpful to extracting weak angle 2 beta + gamma.
11580844
Summary report of the impedance and instability subgroup
This subgroup discussed several technical issues facing the BTCF (Beijing tau-charm factory). Most of these are R and D issues to be performed before a construction start. The two uncertainties facing the B-factories and the BTCF alike, namely the transient ion instability and the photo-electron instability are much weaker in the BTCF. Another uncertainty concerns the monochromator scheme, for which a round of parameters optimization is called for. The R and D issues can be collected into a long list. These discussions are by no means exhaustive, but are listed below as a summary of this report: (1) impedance policing is to be established; (2) single bunch instability is marginally acceptable; (3) beam-beam effects is to be considered together with microwave instability to optimize the overall design; (4) microwave power is a new issue which needs attention; (5) trapped modes need attention; (6) aluminum antechamber vacuum chamber design is recommended; (7) electrostatic separators need to be designed to minimize the microwave power generation; (8) dust particles need attention.