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https://hdl.handle.net/10481/47751
2024-05-18T16:28:02ZPhysics of warped dimensions: discrete and continuous spectra
https://hdl.handle.net/10481/85469
Physics of warped dimensions: discrete and continuous spectra
Megías Fernández, Eugenio; Quirós, Mariano
Using two different warped five-dimensional (5D) models with two
branes along the extra dimension, we study the Green’s functions and the spectral
properties of some of the fields propagating in the bulk. While the first
model has a discrete spectrum of Kaluza-Klein (KK) modes, the second one
has a continuous spectrum above a mass gap. We also study the positivity of the
spectral functions, as well as the coupling of the graviton and the radion with
SM matter fields
Asymptotic freedom using a gluon mass as a regulator
https://hdl.handle.net/10481/85458
Asymptotic freedom using a gluon mass as a regulator
Gálvez Viruet, Juan José; Gómez Rocha, María
Front-Form Hamiltonian dynamics provides a framework in which QCD’s vacuum is simple and
states are boost invariant. However, canonical expressions are divergent and must be regulated in order to
establish well-defined eigenvalue problems. The Renormalization Group Procedure for Effective Particles
(RGPEP) provides a systematic way of finding counterterms and obtaining regulated Hamiltonians. Among its
achievements is the description of asymptotic freedom, with a running coupling constant defined as the coefficient
in front of the three gluon-vertex operators in the regulated Hamiltonian. However, the obtained results need a
deeper understanding, since the coupling exhibits a finite dependence on the regularization functions, at least
at the third-order term in the perturbative expansion. Here we present a similar derivation using a different
regularization scheme based on massive gluons. The procedure can be extended to incorporate contributions
from virtual fermions.
Measurement of the 160Gd(n, γ) cross section at n_TOF and its medical implications
https://hdl.handle.net/10481/85114
Measurement of the 160Gd(n, γ) cross section at n_TOF and its medical implications
Mastromarco, M.; García Infantes, Francisco; Porras Sánchez, José Ignacio; Praena Rodríguez, Antonio Javier; Torres Sánchez, Pablo; n_TOF Collaboration
Neutron-capture reactions on gadolinium isotopes play an important role in several fields of physics, in particular in nuclear Astrophysics for the understanding of the nucleosynthesis of heavy elements (beyond iron) in stars via the s- and r-processes [1] and in nuclear technology. Another important application of gadolinium is linked to the production of terbium, that offers a set of clinically interesting isotopes for theranostics, characterized by complementary physical decay characteristics. In particular, the low -energy beta(-) emitter terbium-161 is very similar to lutetium-177 in terms of half-life (6.89 d), beta(-) - energy and chemical properties. Being a significant emitter of conversion/Auger electrons, greater therapeutic effect can therefore be expected in comparison to Lu-177 [2, 3]. For this reason, in the last decade, the study of the neutron capture reaction Gd-160(n,,gamma)(161) Gd and the subsequent beta(-) - decay in terbium-161 is getting particular attention. As the nuclear data on the Gd-160 neutron capture reaction are quite scarce and inconsistent, a new measurement of the capture cross section of Gd-160 at the CERN neutron Time -Of-Flight facilty was performed in order to provide high resolution, high -accuracy data on this important reaction, in the energy range from thermal to hundreds of keV. In this contribution, the preliminary results of the n_TOF measurement are presented.
Overview of the dissemination of n_TOF experimental data and resonance parameters
https://hdl.handle.net/10481/85105
Overview of the dissemination of n_TOF experimental data and resonance parameters
Dupont, E.; García Infantes, Francisco; Porras Sánchez, José Ignacio; Praena Rodríguez, Antonio Javier; Torres Sánchez, Pablo; n_TOF Collaboration
The n_TOF neutron time-of-flight facility at CERN is used for nuclear data measurements. The n_TOF Collaboration works closely with the Nuclear Reaction Data Centres (NRDC) network to disseminate the experimental data through the international EXFOR library. In addition, the Collaboration helps integrate the results in the evaluated library projects. The present contribution describes the dissemination status of n_TOF results, their impact on evaluated libraries and ongoing efforts to provide n_TOF resonance parameters in ENDF-6 format for further use by evaluation projects.
First high resolution measurement of neutron capture resonances in 176Yb at the n_TOF CERN facility
https://hdl.handle.net/10481/85090
First high resolution measurement of neutron capture resonances in 176Yb at the n_TOF CERN facility
García Infantes, Francisco; Praena Rodríguez, Antonio Javier; Amar Es-Sghir, Hamza; Porras Sánchez, José Ignacio; Torres Sánchez, Pablo; n_TOF Collaboration
Several international agencies recommend the study of new routes and new facilities for producing radioisotopes with application to nuclear medicine. Lu-177 is a versatile radioisotope used for therapy and diagnosis (theranostics) of cancer with good success in neuroendocrine tumours that is being studied to be applied to a wider range of tumours. Lu-177 is produced in few nuclear reactors mainly by the neutron capture on Lu-176. However, it could be produced at high -intensity accelerator-based neutron facilities. The energy of the neutrons in accelerator-based neutron facilities is higher than in thermal reactors. Thus, experimental data on the Yb-176(n,(sic)) cross-section in the eV and keV region are mandatory to calculate accurately the production of Yb-177, which beta decays to 177Lu. At present, there are not experimental data available from thermal to 3 keV of the Yb-176(n,(sic)) cross-section. In addition, there is no data in the resolved resonance region (RRR). This contribution shows the first results of the Yb-176 capture measurement performed at the n_TOF facility at CERN.
We acknowledge to Richard Henkelmann (ITG Company) and Ulli Koester (ILL) for the 176Yb2O3 sample. F.G.I aknowledges the CERN doctoral student programme. This work was partial financial supported from the Spanish Ministerio de Ciencia e Innovacion (Proyectos de I+D+i: PID2020-117969RB-I00), and Junta de Andalucia projects P20-00665 and B-FQM-15-6UGR20.