125558237
Hypernuclear spectrometer system (HNSS) at CEBAF
The hypernuclear spectrometer system at CEBAF and experimental setup are discussed. The SOS (short orbit spectrometer) built for Hall C at CEBAF and an existing high resolution Enge split‐pole spectrometer will form a hypernuclear spectrometer system with energy resolution on the order of 1 MeV and relative low cost. It will be used to perform the first phase experiments which will provide valuable and important information on rates and performance of the coincidence measurements. This information will guide us for future hypernuclear physics studies. This would enable us to start the first phase hypernuclear experiments as early as in 1995.
125394021
gamma-ray spectroscopy of (Lambda)Be-9
122783059
Radio frequency picosecond phototube
Abstract We propose a photon detector for recording low-level and ultra-fast optical signals, based on radio frequency (RF) analysis of low-energy photoelectrons (PEs). By using currently developed 500 MHz RF deflector, it is possible to scan circularly and detect single PEs, amplified in multi-channel plates (MCPs). The operation of the tube is investigated by means of thermionic electron source. It is demonstrated that the signals generated in the MCP can be processed event by event; by using available nanosecond electronics and that time resolution better than 20 ps can be achieved. Timing characteristics of the Cherenkov detector with RF phototube in a ‘head-on’ geometry is investigated by means of Monte Carlo simulation.
123272214
New (e,e′K+) hypernuclear spectroscopy with a high resolution kaon spectrometer
Abstract A new ( e , e ′ K + ) hypernuclear spectroscopy is proposed at Jefferson Lab. With a newly designed high resolution kaon spectrometer (HKS) and a new experimental configuration to reduce background electrons associated with bremsstrahlung, it is expected to realize much higher yield and hypernuclear mass resolution than those of the first successful experiment at Jefferson Lab Hall-C, which demonstrated the feasibility of hypernuclear electroproduction for Λ hypernuclear spectroscopy.
119255652
Bucking coil implementation on PMT for active canceling of magnetic field
Aerogel and water Cerenkov detectors were employed to tag kaons for a lambda hypernuclear spectroscopic experiment which used the (e,e'K{sup +}) reaction in experimental Hall C at Jefferson Lab (JLab E05-115). Fringe fields from the kaon spectrometer magnet yielded ~5 Gauss at the photomultiplier tubes (PMT) for these detectors which could not be easily shielded. As this field results in a lowered kaon detection efficiency, we implemented a bucking coil on each photomultiplier tubes to actively cancel this magnetic field, thus maximizing kaon detection efficiency.
122072860
Delayed Pion Spectroscopy of Hypernuclei
New possibilities of hypernuclear studies at modern electron accelerators based on recently developed radio frequency photomultiplier tubes are discussed.
119227533
Molecular states with hidden charm and strange in QCD Sum Rules
This work uses the QCD Sum Rules to study the masses of the and molecular states with quantum numbers . Interpolating currents with definite C-parity are employed, and the contributions up to dimension eight in the Operator Product Expansion (OPE) are taken into account. The results indicate that two hidden strange charmonium-like states may exist in the energy ranges of and , respectively. The hidden strange charmonium-like states predicted in this work may be accessible in future experiments, e.g., BESIII, BelleII and SuperB. Possible decay modes, which may be useful in further research, are predicted.
19203912
Estimating the mass of the hidden charm $$1^+(1^{+})$$1+(1+) tetraquark state via QCD sum rules
By using QCD sum rules, the mass of the hidden charm tetraquark $$[cu][\bar{c}\bar{d}]$$[cu][c¯d¯] state with $$I^{G} (J^{P}) = 1^+ (1^{+})$$IG(JP)=1+(1+) (HCTV) is estimated, which presumably will turn out to be the newly observed charmonium-like resonance $$Z_c^+(3900)$$Zc+(3900). In the calculation, contributions up to dimension eight in the operator product expansion (OPE) are taken into account. We find $$m_{1^+}^c = (3912^{+306}_{-153}) \, \text {MeV}$$m1+c=(3912-153+306)MeV, which is consistent, within the errors, with the experimental observation of $$Z_c^+(3900)$$Zc+(3900). Extending to the b-quark sector, $$m_{1^+}^b = (10561^{+395{}^{}}_{-163}) \,\text {MeV}$$m1+b=(10561-163+395)MeV is obtained. The calculational result strongly supports the tetraquark picture for the “exotic” states of $$Z_c^+(3900)$$Zc+(3900) and $$Z_b^+(10610)$$Zb+(10610).