Search results for "Hyperon"
showing 10 items of 118 documents
Hyperon forward spin polarizability gamma0 in baryon chiral perturbation theory
2015
We present the calculation of the hyperon forward spin polarizability gamma0 using manifestly Lorentz covariant baryon chiral perturbation theory including the intermediate contribution of the spin 3/2 states. As at the considered order the extraction of gamma0 is a pure prediction of chiral perturbation theory, the obtained values are a good test for this theory. After including explicitly the decuplet states, our SU(2) results have a very good agreement with the experimental data and we extend our framework to SU(3) to give predictions to the hyperons' gamma0 values. Prominent are the Sigma^- and Xi^- baryons as their photon transition to the decuplet is forbidden in SU(3) symmetry and th…
Leading-order decuplet contributions to the baryon magnetic moments in chiral perturbation theory
2009
We extend an earlier study of the baryon magnetic moments in chiral perturbation theory by the explicit inclusion of the spin-3/2 decuplet resonances. We find that the corrections induced by these heavier degrees of freedom are relatively small in a covariant framework where unphysical spin-1/2 modes are removed. Consequently, implementing the leading SU(3)-breaking corrections given by both the baryon and decuplet contributions, we obtain a description of the baryon-octet magnetic moments that is better than the Coleman-Glashow relations. Finally, we discuss the uncertainties and compare between heavy baryon and covariant approaches. (C) 2009 Elsevier B.V. All rights reserved.
Isospin 0 and 1 resonances fromπΣphotoproduction data
2013
Recently we presented a successful strategy to extract the position of the two $\ensuremath{\Lambda}(1405)$ poles from experimental photoproduction data on the $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{0}{\ensuremath{\Sigma}}^{0}$ reaction at Jefferson Lab. Following a similar strategy, we extend the previous method to incorporate also the isospin 1 component which allows us to consider in addition the experimental data on $\ensuremath{\gamma}p\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}{\ensuremath{\Sigma}}^{\ensuremath{\mp}}$. The idea is based on considering a production mechanism as model independent as possible and imple…
Baryon decuplet in the chiral dynamics of Λ hyperons in nuclear matter
2007
6 pages, 5 figures.-- PACS nrs.: 21.80.+a; 21.65.+f; 13.75.Ev; 24.10.Cn.-- ISI Article Identifier: 000245332200063.-- ArXiv pre-print available at: http://arxiv.org/abs/nucl-th/0611082
Evidence for the decayX(3872)→J/ψω
2010
We present a study of the decays B^(0,+)→J/ψπ^+π^-π^0K^(0,+), using 467×10^6 BB[overbar] pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872)→J/ψω, with product branching fractions B(B^+→X(3872)K^+)×B(X(3872)→J/ψω)=[0.6±0.2(stat)±0.1(syst)]×10^(-5), and B(B^0→X(3872)K^0)×B(X(3872)→J/ψω)=[0.6±0.3(stat)±0.1(syst)]×10^(-5). A detailed study of the π^+π^-π^0 mass distribution from X(3872) decay favors a negative-parity assignment.
Antistrange meson-baryon interaction in hot and dense nuclear matter
2014
We present a study of in-medium cross sections and (off-shell) transition rates for the most relevant binary reactions for strange pseudoscalar meson production close to threshold in heavy-ion collisions at FAIR energies. Our results rely on a chiral unitary approach in coupled channels which incorporates the $s$- and $p$-waves of the kaon-nucleon interaction. The formalism, which is modified in the hot and dense medium to account for Pauli blocking effects, mean-field binding on baryons, and pion and kaon self-energies, has been improved to implement full unitarization and self-consistency for both the $s$- and $p$-wave interactions at finite temperature and density. This gives access to i…
Exploring the potential of antihyperons in nuclei with antiprotons
2008
A simple method to explore the interaction of antihyperons in nuclei by exclusive hyperon-antihyperon pair production close to threshold in antiproton nucleus interactions is proposed. Due to energy and momentum conservation event-by-event transverse momentum correlations of the produced hyperons and antihyperons contain information on the difference between their potentials. A schematic Monte Carlo simulation is used to illustrate the sensitivities of the proposed method for the reaction 1.66GeV/c antiproton+$^{12}$C $\to {\Lambda\bar{\Lambda}}$. For produced D-meson pairs at 6.7GeV/c the sensitivity of the transverse momenta correlation will probably be to small to deduce differences betw…
Searches for the baryon- and lepton-number violating decaysB0→Λc+l−,B−→Λl−, andB−→Λ¯l−
2011
Searches for $B$ mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either $\Lambda_c$ or $\Lambda$ and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range $(3.2-520) \times 10^{-8}$ are set on the branching fractions at the 90% confidence level.
The (K-, p) reaction on nuclei with in-flight kaons
2010
10th International Conference on Hypernuclear and Strange Particle Physics. Tokai, JAPAN, SEP 14-18, 2009
Production of hypernuclei in peripheral relativistic ion collisions
2013
Within a dynamical and statistical approach we study the main regularities in production of hypernuclei coming from projectile and target residues in relativistic ion collisions. We demonstrate that yields of hypernuclei increase considerably above the energy threshold for Lambda hyperons, and there is a saturation for yields of single hypernuclei with increasing the beam energy up to few TeV. Production of specific hypernuclei depend very much on the isotopic composition of the projectile, and this gives a chance to obtain exotic hypernuclei that may be difficult to reach in traditional hypernuclear experiments. Possibilities for the detection of such hypernuclei with planned and available…