Could Zb(10610)Z_{b}(10610) be a B∗BˉB^{*}\bar{B} molecular state?

Assuming the newly observed structure $Z_{b}(10610)$ as a bottomonium-like molecular state $B^{*}\bar{B}$, we calculate its mass in the framework of QCD sum rules. The numerical result is $10.54\pm0.22 GeV$ for $B^{*}\bar{B}$, which coincide with the mass of $Z_{b}(10610)$. This consolidates the statement made by Belle Collaboration that the $Z_{b}(10610)$ resonance could be a $B^{*}\bar{B}$ molecular state.Comment: 6 pages, 3 figures; misprints corrected; the version accepted for publication in Phys. Lett.

Electromagnetic form factors of the Λ\Lambda and Σ\Sigma baryons in an alternative baryonic current approach

Light-cone sum rules are used to investigate the electromagnetic form factors of the $\Lambda$ and $\Sigma$ baryons by using the Ioffe type interpolating currents. The sum rules are affected to some extent by the choice of the interpolating currents from a comparison. Numerical calculations show that the magnetic form factor can be well fitted by the dipole formula for $\Sigma$ but not for $\Lambda$. The magnetic form factor of $\Lambda$ approaches zero with the momentum transfer faster than the dipole formula estimation.Comment: 17 pages, 14 figures, accepted for publication in Phys. Rev.

{Qqˉ}{Qˉ(′)q}\{Q\bar{q}\}\{\bar{Q}^{(')}q\} molecular states

Masses for $\{Q\bar{q}\}\{\bar{Q}^{(')}q\}$ molecular states are systematically studied in QCD sum rules. The interpolating currents representing the related molecular states are proposed. Technically, contributions of the operators up to dimension six are included in operator product expansion (OPE). Mass spectra for molecular states with $\{Q\bar{q}\}\{\bar{Q}^{(')}q\}$ configurations are obtained.Comment: 22 pages, 36 eps figures; revised version accepted for publication in Phys. Rev.

QCD Sum Rule Analysis of Semileptonic Bs1B_{s1}, Bs2∗B^{*}_{s2}, Bs0∗B^{*}_{s0}, and Bs1′B'_{s1} Decays in HQET

We present an analysis of semileptonic decays of orbitally, $P$-wave excited $B_{s}$ meson states $B^{**}_{s}$, including the newly found narrow $B_{s1}(5830)$ and $B^{*}_{s2}(5840)$ states, into low lying $D_{s}$ mesons ($D_{s}(1968)$, $D^{*}_{s}(2112)$, $D_{sJ}(2317)$, $D_{sJ}(2460)$) within the framework of heavy quark effective theory. The relevant universal form factors are estimated using QCD sum rules at the leading-order of the heavy quark expansion. The decay widths are predicted and the branching ratios are estimated.Comment: 18 pages, 8 eps figures, revised version accepted for publication in Phys. Rev.

Semileptonic decay Lambda_c-->Lambda \ell^+ \nu from QCD light-cone sum rules

We present the study of the semileptonic decay \Lambda_c to \Lambda\ell^+\nu by using the light-cone sum rule approach. Distribution amplitudes (DAs) for the \Lambda baryon are discussed to the leading order conformal spin, and QCD sum rule estimate for the corresponding parameters is presented. The form factors describing the decay are calculated and used to predict the decay width and the decay asymmetry parameter \alpha. With the inclusion of twist-3 contributions the calculated decay width \Gamma=(7.2+/-2.0)X10^{-14} GeV as well as asymmetry \alpha=-(0.88+/-0.03) is found in good agreement with the experimental data, while there are appreciable deviations from experiment values when the higher twist contributions are included.Comment: RevTex4, 8 pages, 5 figures, misprints corrected, mini changes in numerical result

Choice of heavy baryon currents in QCD sum rules

In this paper we investigate the effects due to the mixing of two interpolating currents for ground state baryons within the framework of Heavy Quark Effective Theory using the QCD sum rule approach. Both two-point and three-point sum rules, thus the mass, coupling constant and Isgur-Wise function sum rules are considered. It is interesting to contrast those results with each other. Based on the Isgur-Wise functions obtained in this paper, we also analyze the effects of current mixing to Lambda-type and and Sigma-type semi-leptonic decays Lambda_b-->Lambda_c\ell\bar\nu, \Sigma_b-->\Sigma_c\ell\bar\nu and \Sigma_b-->\Sigma^*_c\ell\bar\nu. Decay widths corresponding to various mixing parameters are obtained and can be compared to the experimental data.Comment: RevTeX4, 11 pages with 6 eps figure

Light-cone QCD sum rule approach for the Ξ\Xi baryon electromagnetic form factors and the semileptonic decay Xi_c->Xi e^+nu_e

The electromagnetic form factors of the Xi baryons and the semileptonic decay process Xi_c->Xi e^+nu_e are investigated in the frame work of the light-cone QCD sum rule method with Ioffe-type interpolating currents. Our estimates on the magnetic moments are $mu_{Xi^0}=-(1.75\pm0.21) mu_N and mu_{Xi^-}=-(1.01\pm0.11)mu_N. The decay width of the semileptonic process is expected to be Gamma(\Xi_c\to \Xi e^+\nu_e)=(6.17^{+2.24}_{-2.48})\times10^{-14}GeV. The results make sure that the adoption of this type interpolating current improve the calculations of the magnetic form factors and give more reliable prediction for the analysis of the semileptonic decay process.Comment: 22 pages, 9 figure

Deciphering triply heavy baryons in terms of QCD sum rules

The mass spectra of ground-state triply heavy baryons are systematically unscrambled and computed in QCD sum rules. With a tentative $(QQ)-(Q')$ configuration for $QQQ'$, the interpolating currents representing the triply heavy baryons are proposed. Technically, contributions of the operators up to dimension six are included in operator product expansion (OPE). The numerical results are presented in comparison with other theoretical predictions.Comment: 9 pages with 8 eps figures, accepted for publication in Phys. Lett.

(Qsˉ)(∗)(Qˉs)(∗)(Q\bar{s})^{(*)}(\bar{Q}s)^{(*)} molecular states from QCD sum rules: a view on Y(4140)

Masses for the $(Q\bar{s})^{(*)}(\bar{Q}s)^{(*)}$ ($Q=c$ or $b$) molecular states are systematically computed in the framework of QCD sum rules. Technically, contributions of the operators up to dimension six are included in operator product expansion (OPE). The numerical result $4.13\pm0.10 {GeV}$ for $D_{s}^{*}\bar{D}_{s}^{*}$ agrees well with the mass $4143.0\pm2.9\pm1.2 {MeV}$ for Y(4140), which supports the $D_{s}^{*}\bar{D}_{s}^{*}$ molecular configuration for Y(4140).Comment: 8 pages, 6 figure

Investigating different structures of the Z_{b}(10610) and Z_{b}(10650)

The recently observed narrow resonance $Z_{b}(10610)$ is examined with the assumptions both as a $B^{*}\bar{B}$ molecular state and a $[bd][\bar{b}\bar{u}]$ tetraquark state with quantum numbers $I^{G}J^{P}=1^{+}1^{+}$. Possible interpolating currents are constructed to describe the $Z_{b}(10650)$ as an axial-vector $B^{*}\bar{B}^{*}$ molecular state or a $[bd][\bar{b}\bar{u}]$ tetraquark state. Using QCD sum rules (QCDSR), we consider contributions up to dimension six in the operator product expansion (OPE) at the leading order in $\alpha_{s}$. The mass is obtained as $(10.44\pm0.23) GeV$ for molecular state and $(10.50\pm0.19) GeV$ for tetraquark state, both of which coincide with the $Z_{b}(10610)$. The results $m_{B^{*}\bar{B}^{*}}=(10.45\pm0.31) GeV$ and $m_{[bd][\bar{b}\bar{u}]}=(10.48\pm0.33) GeV$ are consistent with the $Z_{b}(10650)$.Comment: 17 pages, 9 figure