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n_TOF Collaboration(Tarrio, D. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2014). Measurement of the angular distribution of fission fragments using a PPAC assembly at CERN n_TOF. Nucl. Instrum. Methods Phys. Res. A, 743, 79–85.
Abstract: A fission reaction chamber based on Parallel Plate Avalanche Counters (PPACs) was built for measuring angular distributions of fragments emitted in neutron-induced fission of actinides at the neutron beam available at the Neutron Time-Of-Flight (n_TOF) facility at CERN. The detectors and the samples were tilted 45 degrees with respect to the neutron beam direction to cover all the possible values of the emission angle of the fission fragments. The main features of this setup are discussed and results on the fission fragment angular distribution are provided for the Th-232(n,f) reaction around the fission threshold. The results are compared with the available data in the literature, demonstrating the good capabilities of this setup.
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ATLAS Collaboration(Aad, G. et al), Cabrera Urban, S., Castillo Gimenez, V., Costa, M. J., Ferrer, A., Fiorini, L., et al. (2015). Search for pair-produced long-lived neutral particles decaying to jets in the ATLAS hadronic calorimeter in pp collisions at root s=8 TeV. Phys. Lett. B, 743, 15–34.
Abstract: The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a scalar boson to a pair of long-lived particles, neutral under the Standard Model gauge group, in 20.3 fb(-1) of data collected in proton-proton collisions at root s = 8 TeV. This search is sensitive to long-lived particles that decay to Standard Model particles producing jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses from 100 GeV to 900 GeV, and a long-lived neutral particle mass from 10 GeV to 150 GeV.
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Binosi, D., Chang, L., Papavassiliou, J., & Roberts, C. D. (2015). Bridging a gap between continuum-QCD and ab initio predictions of hadron observables. Phys. Lett. B, 742, 183–188.
Abstract: Within contemporary hadron physics there are two common methods for determining the momentum-dependence of the interaction between quarks: the top-down approach, which works toward an ab initio computation of the interaction via direct analysis of the gauge-sector gap equations; and the bottom-up scheme, which aims to infer the interaction by fitting data within a well-defined truncation of those equations in the matter sector that are relevant to bound-state properties. We unite these two approaches by demonstrating that the renormalisation-group-invariant running-interaction predicted by contemporary analyses of QCD's gauge sector coincides with that required in order to describe ground-state hadron observables using a nonperturbative truncation of QCD's Dyson-Schwinger equations in the matter sector. This bridges a gap that had lain between nonperturbative continuum-QCD and the ab initioprediction of bound-state properties.
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Felix-Beltran, O., Gonzalez-Canales, F., Hernandez-Sanchez, J., Moretti, S., Noriega-Papaqui, R., & Rosado, A. (2015). Analysis of the quark sector in the 2HDM with a four-zero Yukawa texture using the most recent data on the CKM matrix. Phys. Lett. B, 742, 347–352.
Abstract: In this Letter we analyse, in the context of the general 2-Higgs Doublet Model, the structure of the Yukawa matrices, (Y) over tilde (q)(1,2), by assuming a four-zero texture ansatz for their definition. In this framework, we obtain compact expressions for (Y) over tilde (q)(1,2), which are reduced to the Cheng and Sher ansatz with the difference that they are obtained naturally as a direct consequence of the invariants of the fermion mass matrices. Furthermore, in order to avoid large flavour violating effects coming from charged Higgs exchange, we consider the main flavour constraints on the off-diagonal terms of Yukawa texture ((chi) over tilde (q)(j))(kl) (k not equal l). We perform a chi(2)-fit based on current experimental data on the quark masses and the Cabibbo-KobayashiMaskawa mixing matrix V-CKM. Hence, we obtain the allowed ranges for the parameters (Y) over tilde (q)(1,2) at 1 sigma for several values of tan beta. The results are in complete agreement with the bounds obtained taking into account constraints on Flavour Changing Neutral Currents reported in the literature.
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Olmo, G. J., & Rubiera-Garcia, D. (2015). Brane-world and loop cosmology from a gravity-matter coupling perspective. Phys. Lett. B, 740, 73–79.
Abstract: We show that the effective brane-world and the loop quantum cosmology background expansion histories can be reproduced from a modified gravity perspective in terms of an f (R) gravity action plus a g(R) term non-minimally coupled with the matter Lagrangian. The reconstruction algorithm that we provide depends on a free function of the matter density that must be specified in each case and allows to obtain analytical solutions always. In the simplest cases, the function f (R) is quadratic in the Ricci scalar, R, whereas g(R) is linear. Our approach is compared with recent results in the literature. We show that working in the Palatini formalism there is no need to impose any constraint that keeps the equations second order, which is a key requirement for the successful implementation of the reconstruction algorithm.
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