21,114 research outputs found
The electromagnetic decays of the charmed and bottom baryons in chiral perturbation theory
We have investigated the electromagnetic decays of the antitriplet and sextet
charmed baryon systems with in the
framework of the heavy baryon chiral perturbation theory. We first construct
the chiral Lagrangians at and . Then we calculate the
electromagnetic (EM) decay amplitudes of the charmed baryon systems up to
. With the help of the quark model, we estimate the low energy
constants. The numerical results of the EM decay widths show good convergence
of the chiral expansion. We notice that the two neutral EM decay processes
and
are strongly suppressed by the SU(3) U-spin flavor symmetry. With the same
formalism, we also estimate the EM decay widths of the bottomed baryons. The EM
decay widths of the heavy baryons may be measured at facilities such as LHCb
and JPARC. The explicit chiral structures of the heavy baryon decay amplitudes
derived in this work may be useful to the possible chiral extrapolations of the
future lattice simulations of these EM decay amplitudes
Exotic , and states
After constructing the possible and
tetraquark interpolating currents in a systematic way, we
investigate the two-point correlation functions and extract the corresponding
masses with the QCD sum rule approach. We study the ,
and systems with various isospins . Our numerical analysis indicates that the masses of doubly-bottomed
tetraquark states are below the threshold of the two bottom mesons, two bottom
baryons and one doubly bottomed baryon plus one anti-nucleon. Very probably
these doubly-bottomed tetraquark states are stable.Comment: 37 pages, 2 figure
Possible Deuteron-like Molecular States Composed of Heavy Baryons
We perform a systematic study of the possible loosely bound states composed
of two charmed baryons or a charmed baryon and an anti-charmed baryon within
the framework of the one boson exchange (OBE) model. We consider not only the
exchange but also the , , , and
exchanges. The mixing effects for the spin-triplets are also taken into
account. With the derived effective potentials, we calculate the binding
energies and root-mean-square (RMS) radii for the systems
, ,
,
and
. Our numerical results indicate that: (1)
the H-dibaryon-like state does not exist; (2) there may
exist four loosely bound deuteron-like states and
with small binding energies and large RMS radii.Comment: 17 pages, 32 figure
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