15695185
Systematic study on QCD interactions of heavy mesons with ρ meson
Abstract The strong interactions of the negative-parity heavy mesons with ρ meson may be described consistently in the context of an effective Lagrangian, which is invariant under isospin SU ( 2 ) transformation. Four coupling constants g H H ρ , f H ∗ H ρ , g H ∗ H ∗ ρ and f H ∗ H ∗ ρ enter the effective Lagrangian, where H ( H ∗ ) denotes a pseudoscalar bottom or charm meson (the corresponding vector meson). Using QCD light cone sum rule (LCSR) method and, as inputs, the hadronic parameters updated recently, we give an estimate of g H ∗ H ∗ ρ and f H ∗ H ∗ ρ , about which little was known before, and present an improved result for g H H ρ and f H ∗ H ρ . Also, we examine the heavy quark asymptotic behavior of these nonperturbative quantities and assess the two low energy parameters β and λ of the corresponding effective chiral Lagrangian.
115770456
B -> K*gamma in the light-cone QCD sum rule
A new estimate of the electromagnetic penguin operator contribution to B-->K*gamma is proposed by using the light-cone QCD sum rule. We improve the previous investigation of Ali, Braun and Simma by proper choices of the current operators in the correlator. The reasonable estimates of the b-quark pole mass m(b) and decay constant f(B) are also given. Numerically, we find that the form factor FB-->K*(0) = 0.34 +/- 0.05 and the branching ratio B(B-->K*gamma) = (5.1 +/- 1.7) X 10(-5), with a b-quark pole mass m(b) = 4.7-4.9 GeV. Our results are different from those of Ali et al., but the resulting branching ratio is still comparable with the experimental observation.
119073126
Improved approach to the heavy to light form-factors in the light cone QCD sum rules
A systematic analysis shows that the main uncertainties in the form factors are due to the twist-3 wave functions of the light mesons in the light-cone QCD sum rules. We propose an improved approach, in which the twist-3 wave functions do not make any contribution and therefore the possible pollution by them can be avoided, to reexamine B-->pi semileptonic form factors. Also, a comparison between previous results and our results from the light-cone QCD sum rules is made. Our method will be beneficial to the precise extraction of \V-ub\ from the experimental data on the processes B-->pil )over tilde>(l).
14803102
Strong couplings of heavy mesons to a light vector meson in QCD
We make a detailed analysis of the $BB\rho(DD\rho)$ and $B^*B\rho(D^{*}D\rho)$ strong couplings $g_{BB\rho}(g_{DD\rho})$ and $g_{B^*B\rho}(g_{D^{*}D\rho})$ using QCD light cone sum rules(LCSR). The existing some negligence is pointed out in the previous LCSR calculation on $g_{B^*B\rho} (g_{D^{\ast}D\rho}$) and an updated estimate is presented. Our findings can be used to understand the behavior of the $B,D \to \rho$ semileptonic form factors at large momentum transitions.
14686196
Importance of Higher Twist Effects to Understand Charmed Color-Suppressed $B$ Decays
Working within the framework of the QCD light cone sum rules (LCSR), we compute and discuss the nonfactorizable higher twist effect in $\bar{B}^0\to D^{*0}\pi^0$ to make an all-around examination of its role in the charmed color-suppressed B decays. Analogously to the case of $\bar{B}^0\to D^{0}\pi^0$, such effect turns out to be of the same strong phase as the factorizable amplitude, and modifies constructively the magnitude by order $(40-90)%$ so that the effective coefficient $a_2^{f}=C_1+C_2/3$ receives a positive correction comparable numerically with it. Nonleading as the soft effect in question is, our findings for it, along with the previous LCSR analyses of $\bar{B}^0\to D^{0}\pi^0$, are suggestive of the dominance of soft exchanges in these charmed color suppressed B decays. Also, the emphases are put on importance of understanding intensively various related higher twist and transverse momentum effects to interpret the data on $B \to D^{0(*0)}(\pi^0,\eta,\eta'),J/\psi K^{(*)}$.
119164145
Heavy-to-light transition form factors and their relations in light-cone QCD sum rules
The light-cone QCD sum rules approach improved by using the chiral current correlator is systematically reviewed and applied to the calculation of all the heavy-to-light form factors, including all the semileptonic and penguin ones. By choosing suitable chiral currents, the light-cone sum rules for all the form factors are greatly simplified and depend mainly on one leading-twist distribution amplitude of the light meson. As a result, relations between these form factors arise naturally. At the considered accuracy, these relations reproduce the results obtained in the literature. Moreover, since the explicit dependence on the leading-twist distribution amplitudes is preserved, these relations may be more useful to simulate the experimental data and extract information on the distribution amplitude.
119213488
Correlations in Horizontal Branch Oscillations and Break Components in XTE J1701-462 and GX 17+2
We studied the horizontal branch oscillations (HBO) and the band-limited components observed in the power spectra of the transient neutron star low-mass X-ray binary XTE J1701-462 and the persistent "Sco-like" Z source GX 17+2. These two components were studied based on the state-resolved spectra. We found that the frequencies of XTE J1701-462 lie on the known correlations (WK and PBK), showing consistency with other types of X-ray binaries (black holes, atoll sources, and millisecond X-ray pulsars). However, GX 17+2 is shifted from the WK correlation like other typical Z sources. We suggest that the WK/PBK main track forms a boundary that separates persistent sources from transient sources. The characteristic frequencies of break and HBO are independent of accretion rate in both sources, though it depends on spectral models. We also report the energy dependence of the HBO and break frequencies in XTE J1701-462 and how the temporal properties change with spectral state in XTE J1701-462 and GX 17+2. We studied the correlation between rms at the break and the HBO frequency. We suggest that HBO and break components for both sources probably arise from a similar physical mechanism: Comptonization emission from the corona. These two components could be caused by the same kind of oscillation in a corona with uneven density, and they could be generated from different areas of the corona. We further suggest that different proportions of the Comptonization component in the total flux cause the different distribution between GX 17+2 and XTE J1701-462 in the rmsbreak-rmsHBO diagram.
119274339
Effect of the splitting of the neutron and proton effective masses on the nuclear symmetry energy at finite temperatures
Abstract We present the temperature and density dependence of symmetry energy for nuclear matter at finite temperatures based on the thermodynamics approach with the Skyrme energy density functional. We first classify the Skyrme interactions into 7 groups according to their ranges of the variation of neutron and proton effective masses with densities in neutron matter limit (99.99 percent neutron in the matter). We find that there is an obvious correlation between the temperature dependence of the symmetry energy and the splitting of neutron and proton effective mass. For the Skyrme interactions with m n ⁎ > m p ⁎ and the strong neutron and proton effective mass splitting in asymmetric nuclear matter, a transition of symmetry energy from decreasing with temperature at low densities to increasing with temperature at high densities appears. For other Skyrme interactions, we do not observe this phenomenon and the symmetry energy decreases with temperature in the entire density region.
122278849
Neutron star structure with modern nucleonic three-body forces
We provide convenient parametrizations of the high-density nuclear equation of state obtained within the Brueckner-Hartree-Fock approach using different modern nucleon-nucleon potentials together with compatible microscopic nuclear three-body forces. The corresponding neutron star mass-radius relations are also presented.
6602704
Unified approach to pseudoscalar meson photoproductions off nucleons in the quark model
A unified approach to the pseudoscalar meson (pi, eta, and K) photoproductions off nucleons are presented. It begins with the low energy QCD Lagrangian, and the resonances in the s and u channels are treated in the framework of thr quark modal. The duality hypothesis is imposed to limit the number of the t-channel exchanges. The CGLN amplitudes for each reaction are evaluated, which include both proton and neutron targets. The important role of the S-wave resonances in the second resonance region is discussed, and is particularly important for the K, eta, and eta' photoproductions.
123197092
Mass parameters for relative and neck collective motions in heavy ion fusion reactions
Mass parameters for the relative and neck motions in fusion reactions of symmetric systems $^{90}\mathrm{Zr}+^{90}\mathrm{Zr}$, $^{110}\mathrm{Pd}+^{110}\mathrm{Pd}$, and $^{138}\mathrm{Ba}+^{138}\mathrm{Ba}$ are studied by means of a microscopic transport model. The shape of the nuclear system is determined by an equidensity surface obtained from the density distribution of the system. The relative and neck motions are then studied and the mass parameters for these two motions are deduced. The mass parameter for the relative motion is around the reduced mass when the reaction partners are at the separated configuration and increases with a decrease of the distance between two reaction partners after the touching configuration. The mass parameter for the neck motion first decreases slightly up to the touching configuration and then increases with the neck width, and its magnitude is from less than a tenth to several times more than the total mass of the system. The mass parameters obtained from the microscopic transport model are larger than the ones obtained from the hydrodynamic model and smaller than those obtained from the linear response function theory. The mass parameters for both motions depend on the reaction systems, but the one for the relative motion depends on the incompressibility of the EoS more obviously than that for neck motion.