Search results for "MBD"
showing 10 items of 646 documents
Observation of the Doubly StrangebBaryonΩb−
2008
We report the observation of the doubly strange b baryon Omega(-)(b) in the decay channel Omega(-)(b) -> J/psi Omega(-), with J/psi -> mu(+)mu(-) and Omega(-) -> Lambda K- -> (p pi(-))K-, in p (p) over bar collisions at root s = 1.96 TeV. Using approximately 1.3 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8 +/- 4.9(stat) +/- 0.8(syst) Omega(-)(b) signal events at a mass of 6.165 +/- 0.010(stat) +/- 0.013(syst) GeV. The significance of the observed signal is 5.4 sigma, corresponding to a probability of 6.7 x 10(-8) of it arising from a background fluctuation.
Weak decays of heavy hadrons into dynamically generated resonances
2016
In this paper, we present a review of recent works on weak decay of heavy mesons and baryons with two mesons, or a meson and a baryon, interacting strongly in the final state. The aim is to learn about the interaction of hadrons and how some particular resonances are produced in the reactions. It is shown that these reactions have peculiar features and act as filters for some quantum numbers which allow to identify easily some resonances and learn about their nature. The combination of basic elements of the weak interaction with the framework of the chiral unitary approach allow for an interpretation of results of many reactions and add a novel information to different aspects of the hadron…
One-Pion Charm Baryon Transitions in a Relativistic Three-Quark Model
1998
We study one-pion transitions between charm baryon states in the framework of a relativistic three-quark model. We calculate the charm baryon-pion coupling factors that govern the S-wave, P-wave and D-wave one-pion transitions from the s-wave and the lowest lying p-wave charm baryon states down to the s-wave charm baryon states. For these we obtain: g_{\Sigma_c\Lambda_c\pi}=8.88 GeV^{-1}, f_{\Lambda_{c1}\Sigma_c\pi}=0.52 and f_{\Lambda_{c1}^*\Sigma_c\pi}=21.5 GeV^{-2}. We compare our rate predictions for the one-pion transitions with experimental results.
Diquark-diquark correlations in theS01ΛΛpotential
2005
We derive a $\ensuremath{\Lambda}\ensuremath{\Lambda}$ potential from a chiral constituent quark model that has been successful in describing one, two, and three nonstrange baryon systems. The resulting interaction at low energy is attractive at all distances due to the $\ensuremath{\sigma}$ exchange term. The attraction allows for a slightly bound state just below the $\ensuremath{\Lambda}\ensuremath{\Lambda}$ threshold. No short-range repulsive core is found. We extract the diquark-diquark contribution that turns out to be the most attractive and probable at small distances. At large distances the asymptotic behavior of the $\ensuremath{\Lambda}\ensuremath{\Lambda}$ interaction provides a…
The role of N*(2120) nucleon resonance in KΛ(1520) photon and hadronic productions
2013
The associate $K\Lambda(1520)$ photon and hadronic production in the $\gamma p \to K^+\Lambda(1520)$, $p p \to p K^+ \Lambda(1520)$ and $\pi^- p \to K^0 \Lambda(1520)$ reactions are investigated within the effective Lagrangian approach and the isobar model. We are interested in the contribution from the $N^*(2120)$ (previously called $N^*(2080)$) resonance, which has a significant coupling to the $K\Lambda(1520)$ channel. The theoretical results show that the current experimental data for the $\gamma p \to K^+\Lambda(1520)$ reaction favor the existence of the $N^*(2120)$ resonance, and that these measurements can be used to further constrain its properties. We present results, including the…
Structure and function of the vacuolar Ccc1/VIT1 family of iron transporters and its regulation in fungi
2020
Iron is an essential micronutrient for most living beings since it participates as a redox active cofactor in many biological processes including cellular respiration, lipid biosynthesis, DNA replication and repair, and ribosome biogenesis and recycling. However, when present in excess, iron can participate in Fenton reactions and generate reactive oxygen species that damage cells at the level of proteins, lipids and nucleic acids. Organisms have developed different molecular strategies to protect themselves against the harmful effects of high concentrations of iron. In the case of fungi and plants, detoxification mainly occurs by importing cytosolic iron into the vacuole through the Ccc1/V…
L'Analogie chez Aristote
2021
Revue de philosophie dont l’objet est de montrer, d’interroger ou d’évaluer les comparaisons effectives dans les différents champs disciplinaires, Analogia est une publication scientifique annuelle de l’IPC.Chaque numéro réunit un conseil scientifique nouveau chargé de sélectionner les contributions en double aveugle.L’Analogie chez Aristote.Sous la direction d’Emmanuel Brochier.Conseil scientifique :- Katerina Ierodiakonou (Genève – Athènes)- André Laks (Paris)- Benjamin C. Morison (Princeton)- Jean-Luc Solère (Boston)Sommaire :- Présentation, par Emmanuel Brochier, p. 5 ;- Christof Rapp : "Spotting similarities between disparate items" Observations on the use of analogy in Aristotle’s met…
Λc+ production in Pb–Pb collisions at √sNN = 5.02 TeV
2019
A measurement of the production of prompt Λc+ baryons in Pb–Pb collisions at √sNN = 5.02 TeV with the ALICE detector at the LHC is reported. The Λc+ and Λ‾c− were reconstructed at midrapidity (|y|<0.5) via the hadronic decay channel Λc+ → pKS0 (and charge conjugate) in the transverse momentum and centrality intervals 6<pT <12 GeV/c and 0–80%. The Λc+/D0 ratio, which is sensitive to the charm quark hadronisation mechanisms in the medium, is measured and found to be larger than the ratio measured in minimum-bias pp collisions at √s = 7 TeV and in p–Pb collisions at √sNN = 5.02 TeV. In particular, the values in p–Pb and Pb–Pb collisions differ by about two standard deviations of the combined s…
Existence of fixed point for GP(Λ;Θ)-contractive mappings in GP-metric spaces
2017
We combine some classes of functions with a notion of hybrid $GP_{(\Lambda,\Theta )}$ - $H$ - $F$ - contractive mapping for establishing some fixed point results in the setting of $GP$-metric spaces. An illustrative example supports the new theory.
Search for a Stable Six-Quark State at BABAR
2019
Recent investigations have suggested that the six-quark combination uuddss could be a deeply bound state (S) that has eluded detection so far, and a potential dark matter candidate. We report the first search for a stable, doubly strange six-quark state in Upsilon -> S anti-Lambda anti-Lambda decays based on a sample of 90 million Upsilon(2S) and 110 million Upsilon(3S) decays collected by the BABAR experiment. No signal is observed, and 90% confidence level limits on the combined Upsilon(2S,3S) -> S anti-Lambda anti-Lambda branching fraction in the range (1.2-1.4)x10^-7 are derived for m_S < 2.05 GeV. These bounds set stringent limits on the existence of such exotic particles.