118038694
QCD sum rule analysis of baryon masses
12588055
Predictive ability of QCD sum rules for excited baryons
The masses of octet baryons are calculated by the method of QCD sum rules. Using generalized interpolating fields, three independent sets of QCD sum rules are derived which allow the extraction of low-lying N* states with spin-parity 1/2+, 1/2- and 3/2- in both the non-strange and strange channels. The predictive ability of the sum rules is examined by a Monte Carlo based analysis procedure in which the three phenomenological parameters (mass, coupling, threshold) are treated as free parameters simultaneously. Realistic uncertainties in these parameters are obtained by simultaneously exploring all uncertainties in the QCD input parameters. Those sum rules with good predictive power are identified and their predictions are compared with experiment where available.
118772195
N* Masses from QCD Sum Rules
We report N* masses in the spin-1/2 and spin-3/2 sectors using the method of QCD Sum Rules. They are based on three independent sets derived from generalized interpolating fields. The predictive ability of each sum rule is examined by a Monte-Carlo based analysis procedure in which all three phenomenological parameters (mass, coupling, threshold) are extracted simultaneously. A parity projection technique is also studied.
119203353
The hidden charm decay of Y(4140) by the rescattering mechanism
Abstract Assuming that Y ( 4140 ) is the second radial excitation of the P-wave charmonium χ c J ″ ( J = 0 , 1 ), the hidden charm decay mode of Y ( 4140 ) is calculated in terms of the rescattering mechanism. Our numerical results show that the upper limit of the branching ratio of the hidden charm decay Y ( 4140 ) → J / ψ ϕ is on the order of 10 − 4 – 10 − 3 for both of the charmonium assumptions for Y ( 4140 ) , which disfavors the large hidden charm decay pattern indicated by the CDF experiment. It seems to reveal that the pure second radial excitation of the P-wave charmonium χ c J ″ ( J = 0 , 1 ) is problematic.
119282967
Masses and axial currents of the doubly charmed baryons
The chiral dynamics of the doubly heavy baryons is solely governed by the light quark. In this work, We have derived the chiral corrections to the mass of the doubly heavy baryons up to N$^3$LO. The mass splitting of $\Xi_{cc}$ and $\Omega_{cc}$ at the N$^2$LO depends on one unknown low energy constant $c_7$. With the experimental mass of $\Xi_{cc}(3520)$ as the input, we estimate the mass of $\Omega_{cc}$ to be around 3.678 GeV. Moreover, we have also performed a systematical analysis of the chiral corrections to the axial currents and axial charges of the doubly heavy baryons. The chiral structure and analytical expressions will be very useful to the chiral extrapolations of the future lattice QCD simulations of the doubly heavy baryons.
118457798
New structure around 3250 MeV in the baryonic B decay and the $D^{*}_{0}(2400)N$ molecular hadron
In this work, we first propose the isovector $nD^{*}_{0}(2400)^{0}$ molecular state to explain the enhancement structure around 3250 MeV (Xc(3250)0) in the $\varSigma_{c}^{++}\pi^{-}\pi^{-}$ invariant mass spectrum newly observed by the BaBar Collaboration. Under this molecular state configuration, both the analysis of the mass spectrum and the study of its dominant decay channel can well shed light on its resonance parameters measured by BaBar. Our investigation also shows that the isovector $nD^{*}_{0}(2400)^{0}$ molecular state can decay into $\varSigma_{c}^{++}\pi^{-}\pi^{-}$, which is consistent with experimental observation. These studies provide direct support to the isovector $nD^{*}_{0}(2400)^{0}$ molecular state assignment to Xc(3250)0.
119232556
D-wave heavy-light mesons from QCD sum rules
We study the D-wave (c) over bars heavy meson doublets (1(-), 2(-)) and (2(-), 3(-)) using the method of QCD sum rule in the framework of heavy quark effective theory. Choosing the same threshold values.c around 2.7 Gev, we calculate the masses of the 1(-) and 3(-) states. They are m(D*s1) = 2.81 +/- 0.10 GeV and m(D*s3) = 2.85 +/- 0.08 GeV, consistent with the newly observed D*(s1)(2860) and D*(s3)(2860) states by LHCb. The masses of their 2-partners are calculated to be 2.82 +/- 0.10 and 2.81 +/- 0.08 GeV. The mass splittings within the same doublet are calculated to be m(Ds2) - m(Ds1) = 0.016 +/- 0.007 GeV and m(D*s3) - m(D's2) = 0.039 +/- 0.014 GeV.
119312762
Structure, spectra and variability of some GPS radio sources
We report the results of multifrequency-VLBI observations of GHz-Peaked-Spectrum (GPS) radio sources. The VLBI structure and component spectra of some GPS sources are presented. Our VLBI results show that about 80% of the GPS galaxies exhibit a compact double or CSO-like structure, white the GPS quasars tend to show a core-jet. The component spectra of the GPS galaxies are often steep/convex, and the core has a flat spectrum but it is usually hidden or weak. In addition, we studied the variability of GPS sources by comparing new flux density measures, acquired with the Urumqi 25-m telescope at 4.85 GHz, with previous 87GB data. The results show that 44% of the GPS quasars varied higher than 10% in passed 20 years, while the fraction is only 12% for the GPS galaxies meaning that the GPS quasars are much more variable than GPS galaxies. In total, 25% of GPS sources show > 10% variability at 4.85 GHz in our sample.