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).
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.
118805500
Study on the mixing among the $0^{++}$ mesons around $1\sim 2$ $\mathrm{GeV}$ with the QCD sum rules
We calculate the correlation functions of $0^{++}$ $q\bar q$, $s\bar s$ and glueball in the QCD sum rules and obtain the mass matrix where non-diagonal terms are determined by the cross correlations among the three states. Diagonalizing the mass matrix and identifying the eigenstates as the physical $0^{++}$ scalar mesons, we can determine the mixing. Concretely, our calculations determine the fractions of $q\bar q$, $s\bar s$ and glueball in the physical states $f_0(1370)$, $f_0(1500)$ and $f_0(1710)$, the results are consistent with that gained by the phenomenological research.
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.
117962966
First Experiment to Produce Lambda-Hypernuclei Using Electron Beam at JLab
117483375
Sigma hyperons in the nucleus
A search for {sigma} hypernuclear states in p -shell hypernuclei has been performed with the Moby Dick spectrometer and the low energy separated beam (LESB-2) at the Brookhaven Alternating Gradient Synchrotron (BNL AGS). Unlike some previously published reports, no narrow states have been observed for targets of {sup 6}Li and {sup 9}Be in (K{sup -}, {pi}{sup {+-}}) reactions, either for bound state or continuum regions. Together with the previously reported J=0 , T=1/2 bound state in {sup 4}{sub {sigma}} He , these results demonstrate the crucial role of isospin in {sigma} hypernuclei. (c) 1999 The American Physical Society.
39223572
Observation of a spin-flip M1 transition in 7(lambda)Li.
Using a large-acceptance germanium detector array (Hyperball), we have observed a spin-flip M1 gamma transition between the ground-state spin doublet of (7)(Lambda)Li (3/2(+)-->1/2(+)). The observed energy of 691.7+/-0.6(stat)+/-1.0(syst) keV provides crucial information on the strength of the spin-spin interaction between a Lambda and a nucleon. This is the first observation of well-identified hypernuclear gamma transitions using germanium detectors.
118438012
Experimental investigation of weak non-mesonic decay of (lambda) Be-10 hypernuclei at CEBAF
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.