|
Nieves, J., Pavao, R., & Tolos, L. (2018). Omega(c) excited states within a SU(6)(lsf) x HQSS model. Eur. Phys. J. C, 78(2), 114–10pp.
Abstract: We have reviewed the renormalization procedure used in the unitarized coupled-channel model of Romanets et al. (Phys Rev D 85: 114032, 2012), and its impact in the C = 1, S = -2, and I = 0 sector, where five Omega((*))(c) states have been recently observed by the LHCb Collaboration. The meson-baryon interactions used in the model are consistent with both chiral and heavy-quark spin symmetries, and lead to a successful description of the observed lowest-lying odd parity resonances Lambda(c)(2595) and Lambda(c)(2625), and Lambda(b)(5912) and Lambda(b)(5920) resonances. We show that some (probably at least three) of the states observed by LHCb will also have odd parity and J = 1/2 or J = 3/2, belonging two of them to the same SU(6)(light-spin-flavor) x HQSS multiplets as the latter charmed and beauty Lambda baryons.
|
|
|
Binosi, D., & Papavassiliou, J. (2018). Coupled dynamics in gluon mass generation and the impact of the three-gluon vertex. Phys. Rev. D, 97(5), 054029–15pp.
Abstract: We present a detailed study of the subtle interplay transpiring at the level of two integral equations that are instrumental for the dynamical generation of a gluon mass in pure Yang-Mills theories. The main novelty is the joint treatment of the Schwinger-Dyson equation governing the infrared behavior of the gluon propagator and of the integral equation that controls the formation of massless bound-state excitations, whose inclusion is instrumental for obtaining massive solutions from the former equation. The self-consistency of the entire approach imposes the requirement of using a single value for the gauge coupling entering in the two key equations; its fulfilment depends crucially on the details of the three-gluon vertex, which contributes to both of them, but with different weight. In particular, the characteristic suppression of this vertex at intermediate and low energies enables the convergence of the iteration procedure to a single gauge coupling, whose value is reasonably close to that extracted from related lattice simulations.
|
|
|
Dias, J. M., Roca, L., & Sakai, S. (2018). Prediction of new states from D(*)B(*)(B)over-bar(*) three-body interactions. Phys. Rev. D, 97(5), 056019–8pp.
Abstract: We study three-body systems composed of D(*), B(*), and (B) over bar(*) in order to look for possible bound states or resonances. In order to solve the three-body problem, we use the fixed center approach for the Faddeev equations considering that the B*(B) over bar*(B (B) over bar) are clusterized systems, generated dynamically, which interact with a third particle D((D) over bar) whose mass is much smaller than the two-body bound states forming the cluster. In the DB*(B) over bar*, D*B*(B) over bar*, DB (B) over bar, and D*B (B) over bar systems with I = 1/2, we found clear bound state peaks with binding energies typically a few tens MeV and more uncertain broad resonant states about ten MeV above the threshold with widths of a few tens MeV.
|
|
|
n_TOF Collaboration(Praena, J. et al), Domingo-Pardo, C., Giubrone, G., Tain, J. L., & Tarifeño-Saldivia, A. (2018). Preparation and characterization of S-33 samples for S-33(n,alpha)Si-30 cross-section measurements at the n_TOF facility at CERN. Nucl. Instrum. Methods Phys. Res. A, 890, 142–147.
Abstract: Thin S-33 samples for the study of the S-33(n,alpha)Si-30 cross-section at the n_TOF facility at CERN were made by thermal evaporation of S-33 powder onto a dedicated substrate made of kapton covered with thin layers of copper, chromium and titanium. This method has provided for the first time bare sulfur samples a few centimeters in diameter. The samples have shown an excellent adherence with no mass loss after few years and no sublimation in vacuum at room temperature. The determination of the mass thickness of S-33 has been performed by means of Rutherford backscattering spectrometry. The samples have been successfully tested under neutron irradiation.
|
|
|
NEXT Collaboration(McDonald, A. D. et al), Alvarez, V., Benlloch-Rodriguez, J. M., Botas, A., Carcel, S., Carrion, J. V., et al. (2018). Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging. Phys. Rev. Lett., 120(13), 132504–6pp.
Abstract: A new method to tag the barium daughter in the double-beta decay of Xe-136 is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba++) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (similar to 2 nm), and detected with a statistical significance of 12.9 sigma over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.
|
|