Search results for "baryon"
showing 10 items of 759 documents
Search forB¯→Λc+Xℓ−ν¯ℓdecays in events with a fully reconstructedBmeson
2012
We present a search for semileptonic B decays to the charmed baryon Λc+ based on 420 fb-1 of data collected at the Υ(4S) resonance with the BABAR detector at the PEP-II e+e- storage rings. By fully reconstructing the recoiling B in a hadronic decay mode, we reduce non-B backgrounds and determine the flavor of the signal B. We statistically correct the flavor for the effect of the B0 mixing. We obtain a 90% confidence level upper limit of B(B →Λc+Xl-ν l)/B(B →Λc+X)<3.5%.
Measurements of absolute hadronic branching fractions of the Λc+ baryon
2016
Kolcu, Onur Buğra (Arel Author) --- Makale 69 yazarlıdır.
The effect of the in-medium Θ+ pentaquark on the kaon optical potential
2005
The kaon nuclear optical potential is studied including the effect of the $\Theta^+$ pentaquark. The one-nucleon contribution is obtained using an extension of the J\"ulich meson-exchange potential as bare kaon-nucleon interaction. Significant differences between a fully self-consistent calculation and the usually employed low-density $T\rho$ approach are observed. The influence of the one-nucleon absorption process, $K N \to \Theta^+$, on the kaon optical potential is negligible due to the small width of the pentaquark. In contrast, the two-nucleon mechanism, $K N N \to \Theta^+ N$, estimated from the coupling of the pentaquark to a two-meson cloud, provides the required amount of addition…
Unifying leptogenesis, dark matter and high-energy neutrinos with right-handed neutrino mixing via Higgs portal
2016
We revisit a model in which neutrino masses and mixing are described by a two right-handed (RH) neutrino seesaw scenario, implying a strictly hierarchical light neutrino spectrum. A third decoupled RH neutrino, $N_{\rm DM}$ with mass $M_{\rm DM}$, plays the role of cold dark matter (DM) and is produced by the mixing with a source RH neutrino, $N_{\rm S}$ with mass $M_{\rm S}$, induced by Higgs portal interactions. The same interactions are also responsible for $N_{\rm DM}$ decays. We discuss in detail the constraints coming from DM abundance and stability conditions, showing that in the hierarchical case ($M_{\rm DM} \gg M_{\rm S}$) there is an allowed window on $M_{\rm DM}$, which necessar…
Scalar contributions to b→c(u)τν transitions
2017
Abstract We perform a comprehensive analysis of scalar contributions in b → c τ ν transitions including the latest measurements of R ( D ( ⁎ ) ) , the q 2 differential distributions in B → D ( ⁎ ) τ ν , the τ polarization asymmetry for B → D ⁎ τ ν , and the bound derived from the total width of the B c meson. We find that scalar contributions with the simultaneous presence of both left- and right-handed couplings to quarks can explain the available data, specifically R ( D ( ⁎ ) ) together with the measured differential distributions. However, the constraints from the total B c width present a slight tension with the current data on B → D ⁎ τ ν in this scenario, preferring smaller values fo…
Diffusion processes involving multiple conserved charges: a first study from kinetic theory and implications to the fluid-dynamical modeling of heavy…
2020
The bulk nuclear matter produced in heavy ion collisions carries a multitude of conserved quantum numbers: electric charge, baryon number, and strangeness. Therefore, the diffusion processes associated to these conserved charges cannot occur independently and must be described in terms of a set of coupled diffusion equations. This physics is implemented by replacing the traditional diffusion coefficients for each conserved charge by a diffusion coefficient matrix, which quantifies the coupling between the conserved quantum numbers. The diagonal coefficients of this matrix are the usual charge diffusion coefficients, while the off-diagonal entries describe the diffusive coupling of the charg…
p−p, p−Λ, and Λ−Λ correlations studied via femtoscopy in pp reactions at √s = 7 TeV
2019
We report on the first femtoscopic measurement of baryon pairs, such as p−p, p−Λ, and Λ−Λ, measured by ALICE at the Large Hadron Collider (LHC) in proton-proton collisions at √s=7 TeV. This study demonstrates the feasibility of such measurements in pp collisions at ultrarelativistic energies. The femtoscopy method is employed to constrain the hyperon-nucleon and hyperon-hyperon interactions, which are still rather poorly understood. A new method to evaluate the influence of residual correlations induced by the decays of resonances and experimental impurities is hereby presented. The p−p, p−Λ, and Λ−Λ correlation functions were fitted simultaneously with the help of a new tool developed spec…
Hidden charm N and Delta resonances with heavy-quark symmetry
2013
A model is developed to describe odd-parity baryon resonances generated dynamically through a unitary baryon-meson coupled-channels approach. The scheme applies to channels with light- and/or heavy-quark content. Distinct features of the model are that i) the interaction is an S-wave contact one, ii) it reduces to the SU(3) Weinberg-Tomozawa Hamiltonian when light pseudoscalar mesons are involved, thus respecting chiral symmetry, iii) spin-flavor is preserved in the light-quark sector, and iv) heavy-quark spin symmetry is fulfilled in the heavy-quark sector. In particular, baryon-meson states with different content in c or in (c) over bar do not mix. The model is a minimal one and it contai…
Multi-boson block factorization of fermions
2017
The numerical computations of many quantities of theoretical and phenomenological interest are plagued by statistical errors which increase exponentially with the distance of the sources in the relevant correlators. Notable examples are baryon masses and matrix elements, the hadronic vacuum polarization and the light-by-light scattering contributions to the muon g-2, and the form factors of semileptonic B decays. Reliable and precise determinations of these quantities are very difficult if not impractical with state-of-the-art standard Monte Carlo integration schemes. I will review a recent proposal for factorizing the fermion determinant in lattice QCD that leads to a local action in the g…
Rapidity correlations in Lambda baryon and proton production in hadronic Z0 decays
1998
In an analysis of multihadronic events recorded at LEP by DELPHI in the years 1992 through 1994, charged hadrons are identified using the measurement of their energy loss and their Cherenkov angle. Rapidity correlations of \La-\La, proton-proton, and \La-proton pairs are compared. The agreement with the string and cluster fragmentation models is tested. For those pairs that frame a meson in terms of rapidity the compensation of strangeness is studied. For \La{}$\overline{\mathrm{p}}$ pairs the additional correlation with respect to charged kaons is analysed.