2,905 research outputs found
Scalar strangeness content of the nucleon and baryon sigma terms
The scalar strangeness content of the nucleon, characterized by the so-called
strangeness-nucleon sigma term, is of fundamental importance in understanding
its sea-quark flavor structure. We report a determination of the octet baryon
sigma terms via the Feynman-Hellmann theorem by analyzing the latest
high-statistics lattice QCD simulations with covariant baryon chiral
perturbation theory up to next-to-next-to-next-to-leading order. In particular,
we predict MeV and MeV, while
the first error is statistical and the second systematic due to different
lattice scales. The predicted is consistent with the latest LQCD
results and the results based on the next-to-next-to-leading order chiral
perturbation theory. Several key factors in determining the sigma terms are
systematically taken into account and clarified for the first time, including
the effects of lattice scale setting, systematic uncertainties originating from
chiral expansion truncations, and constraint of strong-interaction isospin
breaking effects.Comment: 6 pages, 2 figures; version to appear in Physical Review
Octet baryon masses and sigma terms in covariant baryon chiral perturbation theory
We report an analysis of the octet baryon masses using the covariant baryon
chiral perturbation theory up to next-to-next-to-next-to-leading order with and
without the virtual decuplet contributions. Particular attention is paid to the
finite-volume corrections and the finite lattice spacing effects on the baryon
masses. A reasonable description of all the publicly available
lattice QCD data is achieved.Utilyzing the Feynman-Hellmann theorem, we
determine the nucleon sigma terms as MeV and
MeV.Comment: 4 pages; presented by Xiu-Lei Ren at The Seventh International
Symposium on Chiral Symmetry in Hadrons and Nuclei (Chiral 2013), October
27-30, 2013, Beijing, Chin
Baryon chiral perturbation theory with Wilson fermions up to and discretization effects of latest LQCD octet baryon masses
We construct the chiral Lagrangians relevant in studies of the ground-state
octet baryon masses up to by taking into account
discretization effects and calculate the masses up to in the
extended-on-mass-shell scheme. As an application, we study the latest
LQCD data on the ground-state octet baryon masses from the PACS-CS,
QCDSF-UKQCD, HSC, and NPLQCD Collaborations. It is shown that the
discretization effects for the studied LQCD simulations are at the order of one
to two percent for lattice spacings up to fm and the pion mass up to 500
MeV.Comment: 19 pages, 2 figures; discussions extended; version to appear in The
European Physical Journal
Topological Nature of the Phonon Hall Effect
We provide a topological understanding on phonon Hall effect in dielectrics
with Raman spinphonon coupling. A general expression for phonon Hall
conductivity is obtained in terms of the Berry curvature of band structures. We
find a nonmonotonic behavior of phonon Hall conductivity as a function of
magnetic field. Moreover, we observe a phase transition in phonon Hall effect,
which corresponds to the sudden change of band topology, characterized by the
altering of integer Chern numbers. This can be explained by touching and
splitting of phonon bands.Comment: 12 pages, 4 figures. Detailed supplementary file is include
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Calcineurin B-Like Proteins CBL4 and CBL10 Mediate Two Independent Salt Tolerance Pathways in Arabidopsis.
In Arabidopsis, the salt overly sensitive (SOS) pathway, consisting of calcineurin B-like protein 4 (CBL4/SOS3), CBL-interacting protein kinase 24 (CIPK24/SOS2) and SOS1, has been well defined as a crucial mechanism to control cellular ion homoeostasis by extruding Na+ to the extracellular space, thus conferring salt tolerance in plants. CBL10 also plays a critical role in salt tolerance possibly by the activation of Na+ compartmentation into the vacuole. However, the functional relationship of the SOS and CBL10-regulated processes remains unclear. Here, we analyzed the genetic interaction between CBL4 and CBL10 and found that the cbl4 cbl10 double mutant was dramatically more sensitive to salt as compared to the cbl4 and cbl10 single mutants, suggesting that CBL4 and CBL10 each directs a different salt-tolerance pathway. Furthermore, the cbl4 cbl10 and cipk24 cbl10 double mutants were more sensitive than the cipk24 single mutant, suggesting that CBL10 directs a process involving CIPK24 and other partners different from the SOS pathway. Although the cbl4 cbl10, cipk24 cbl10, and sos1 cbl10 double mutants showed comparable salt-sensitive phenotype to sos1 at the whole plant level, they all accumulated much lower Na+ as compared to sos1 under high salt conditions, suggesting that CBL10 regulates additional unknown transport processes that play distinct roles from the SOS1 in Na+ homeostasis
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