428 research outputs found
X(3915) and X(4350) as new members in P-wave charmonium family
The analysis of the mass spectrum and the calculation of the strong decay of
P-wave charmonium states strongly support to explain the newly observed X(3915)
and X(4350) as new members in P-wave charmonium family, i.e.,
for X(3915) and for X(4350).
Under the P-wave charmonium assignment to X(3915) and X(4350), the
quantum numbers of X(3915) and X(4350) must be and
respectively, which provide the important criterion to test P-wave charmonium
explanation for X(3915) and X(4350) proposed by this letter. The decay behavior
of the remaining two P-wave charmonium states with the second radial excitation
is predicted, and experimental search for them is suggested.Comment: 4 pages, 2 figures, 2 tables. More references and discussions added,
typos corrected. Accepted for publication in Phys. Rev. Lett
B_{s1}(5830) and B_{s2}^*(5840)
In this paper we investigate the strong decays of the two newly observed
bottom-strange mesons and in the framework of
the quark pair creation model. The two-body strong decay widths of
and are
calculated by considering to be a mixture between and
states, and to be a state. The double pion
decay of and is supposed to occur via the
intermediate state and . Although the double pion decay
widths of and are smaller than the two-body
strong decay widths of and , one suggests future
experiments to search the double pion decays of and
due to their sizable decay widths.Comment: 9 pages, 8 figures and 6 tables. More references and discussions
added, typos corrected, some descriptions changed. Publication version in PR
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
Origin of giant valley splitting in silicon quantum wells induced by superlattice barriers
Enhancing valley splitting in SiGe heterostructures is a crucial task for
developing silicon spin qubits. Complex SiGe heterostructures, sharing a common
feature of four-monolayer (4ML) Ge layer next to the silicon quantum well (QW),
have been computationally designed to have giant valley splitting approaching 9
meV. However, none of them has been fabricated may due to their complexity.
Here, we remarkably simplify the original designed complex SiGe
heterostructures by laying out the Si QW directly on the Ge substrate followed
by capping a (Ge4Si4)n superlattice(SL) barrier with a small sacrifice on VS as
it is reduced from a maximum of 8.7 meV to 5.2 meV. Even the smallest number of
periods (n = 1) will also give a sizable VS of 1.6 meV, which is large enough
for developing stable spin qubits. We also develop an effective Hamiltonian
model to reveal the underlying microscopic physics of enhanced valley splitting
by (Ge4Si4)n SL barriers. We find that the presence of the SL barrier will
reduce the VS instead of enhancing it. Only the (Ge4Si4)n SL barriers with an
extremely strong coupling with Si QW valley states provide a remarkable
enhancement in VS. These findings lay a solid theoretical foundation for the
realization of sufficiently large VS for Si qubits
Novel charmonium-like structures in the and invariant mass spectra
Stimulated by the new evidence of Y(4274) observed in the
invariant mass spectrum, we first propose the charmonium-like state Y(4274) as
the S-wave molecular state with , which
is supported well by dynamics study of the system composed of the pseudoscalar
and scalar charmed mesons. The S-wave molecular
charmonium appears as the molecular partner of Y(4274), which is in accord with
the enhancement structure appearing at 4.2 GeV in the invariant
mass spectrum from B decays. Our study shows that the enhancement structures,
, the newly observed Y(4274) and the previously announced
in the and invariant mass
spectra, can be understood well under the uniform framework of the molecular
charmonium, which can be tested by future experiments.Comment: 4 pages, 4 figures. Accepted for publication by Phys. Lett.
Few-Body Systems Composed of Heavy Quarks
Within the past ten years many new hadrons states were observed
experimentally, some of which do not fit into the conventional quark model. I
will talk about the few-body systems composed of heavy quarks, including the
charmonium-like states and some loosely bound states.Comment: Plenary talk at the 20th International IUPAP Conference on Few-Body
Problems in Physics, to appear in Few Body Systems (2013
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