1,813 research outputs found
Could be a molecular state?
Assuming the newly observed structure as a bottomonium-like
molecular state , we calculate its mass in the framework of QCD
sum rules. The numerical result is for , which
coincide with the mass of . This consolidates the statement made
by Belle Collaboration that the resonance could be a
molecular state.Comment: 6 pages, 3 figures; misprints corrected; the version accepted for
publication in Phys. Lett.
Electromagnetic form factors of the and baryons in an alternative baryonic current approach
Light-cone sum rules are used to investigate the electromagnetic form factors
of the and 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 but
not for . The magnetic form factor of approaches zero with
the momentum transfer faster than the dipole formula estimation.Comment: 17 pages, 14 figures, accepted for publication in Phys. Rev.
molecular states
Masses for 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
configurations are obtained.Comment: 22 pages, 36 eps figures; revised version accepted for publication in
Phys. Rev.
QCD Sum Rule Analysis of Semileptonic , , , and Decays in HQET
We present an analysis of semileptonic decays of orbitally, -wave excited
meson states , including the newly found narrow
and states, into low lying mesons
(, , , ) 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.
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 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
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
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
configuration for , 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.
molecular states from QCD sum rules: a view on Y(4140)
Masses for the ( or ) 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 for
agrees well with the mass
for Y(4140), which supports the 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 is examined with the
assumptions both as a molecular state and a
tetraquark state with quantum numbers
. Possible interpolating currents are constructed to
describe the as an axial-vector molecular
state or a 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 . The mass is obtained as
for molecular state and for
tetraquark state, both of which coincide with the . The results
and
are consistent with the
.Comment: 17 pages, 9 figure
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