119236104
Fermion correction to the mass of the scalar glueball in QCD sum rule
Contributions of fermions to the mass of the scalar glueball $0^{++}$ are calculated at two-loop level in the framework of QCD sum rules. It obviously changes the coefficients in the operator product expansion (OPE) and shifts the mass of glueball.
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.
121442928
Study of Doubly Heavy Baryon Spectrum via QCD Sum Rules
In this work, we calculate the mass spectrum of doubly heavy baryons with the diquark model in terms of the QCD sum rules. The interpolating currents are composed of a heavy diquark field and a light quark field. Contributions of the operators up to dimension six are taken into account in the operator product expansion. Within a reasonable error tolerance, our numerical results are compatible with other theoretical predictions. This indicates that the diquark picture reflects the reality and is applicable to the study of doubly heavy baryons.
121399962
Time-zero fission-fragment detector based on low-pressure multiwire proportional chambers
Abstract A time-zero fission fragment (FF) detector, based on the technique of low-pressure multiwire proportional chambers (LPMWPC), has been designed and constructed for the heavy hypernuclear lifetime experiment (E95-002) at Thomas Jefferson National Accelerator Facility. Its characteristics and the method of time-zero reconstruction were investigated using fission fragments from a 252 Cf spontaneous fission source. The influence of the ionization energy loss was also studied. It is shown that Heptane, Hexane, and Isobutane gases at a pressure of 1–2 Torr are all suitable for such a FF detector. As desired by experiment, a timing resolution of about 200 ps (FWHM) for a chamber size of 21×21 cm 2 was achieved.
93160583
Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control
Abstract Proton polarization at room temperature, produced in a p-terphenyl crystal by using electron population difference in a photo-excited triplet state of pentacene, was enhanced by utilizing an intense laser with an average power of 1.5 W. It was shown that keeping the sample temperature below 300 K is critically important to prevent the rise of the spin–lattice relaxation rate caused by the laser heating. It is also reported that the magnitude of proton polarization strongly depends on the time structure of the laser pulse such as its width and the time interval between them.
118909286
Optical Calibration For Jefferson Lab HKS Spectrometer
In order to accept very forward angle scattering particles, Jefferson Lab HKS experiment uses an on-target zero degree dipole magnet. The usual spectrometer optics calibration procedure has to be modified due to this on-target field. This paper describes a new method to calibrate HKS spectrometer system. The simulation of the calibration procedure shows the required resolution can be achieved from initially inaccurate optical description.