|
|
Garcia Canal, C. A., Tarutina, T., & Vento, V. (2013). Nuclear and partonic dynamics in the EMC effect. Eur. Phys. J. A, 49(8), 105–5pp.
Abstract: It has been recently confirmed that the magnitude of the EMC effect measured in the electron deep inelastic scattering is linearly related to the short-range correlation scaling factor obtained from electron inclusive scattering. By using a x-rescaling approach we are able to understand the interplay between the quark-gluon and hadronic degrees of freedom in the discussion of the EMC effect.
|
|
|
|
Garzon, E. J., & Oset, E. (2012). Effects of pseudoscalar-baryon channels in the dynamically generated vector-baryon resonances. Eur. Phys. J. A, 48(1), 5–20pp.
Abstract: We study the interaction of vector mesons with the octet of stable baryons in the framework of the local hidden gauge formalism using a coupled-channels unitary approach, including also the pseudoscalar-baryon channels which couple to the same quantum numbers. We examine the scattering amplitudes and their poles, which can be associated to the known J(P) = 1/2(-), 3/2(-) baryon resonances, and determine the role of the pseudoscalar-baryon channels, changing the width and eventually the mass of the resonances generated with only the basis of vector-baryon states.
|
|
|
|
Geng, L. S., Guo, F. K., Hanhart, C., Molina, R., Oset, E., & Zou, B. S. (2010). Study of the f(2)(1270) , f(2)'(1525) , f(0)(1370) and f(0)(1710) in the J/psi radiative decays. Eur. Phys. J. A, 44(2), 305–311.
Abstract: In this paper we present an approach to study the radiative decay modes of the J/psi into a photon and one of the tensor mesons f (2)(1270) , f' (2)(1525) , as well as the scalar ones f (0)(1370) and f (0)(1710) . Especially, we compare predictions that emerge from a scheme where the states appear dynamically in the solution of vector meson-vector meson scattering amplitudes to those from a (admittedly naive) quark model. We provide evidence that it might be possible to distinguish amongst the two scenarios, once improved data are available.
|
|
|
|
n_TOF Collaboration(Guerrero, C. et al), Giubrone, G., & Tain, J. L. (2012). Simultaneous measurement of neutron-induced capture and fission reactions at CERN. Eur. Phys. J. A, 48(3), 29–9pp.
Abstract: The measurement of the capture cross-section of fissile elements, of utmost importance for the design of innovative nuclear reactors and the management of nuclear waste, faces particular difficulties related to the.-ray background generated in the competing fission reactions. At the CERN neutron time-of-flight facility nTOF we have combined the Total Absorption Calorimeter (TAC) capture detector with a set of three U-235 loaded MicroMegas (MGAS) fission detectors for measuring simultaneously two reactions: capture and fission. The results presented here include the determination of the three detection efficiencies involved in the process: epsilon(TAC)(n, f), epsilon(TAC)(n, gamma) and epsilon(MGAS)(n, f). In the test measurement we have succeeded in measuring simultaneously with a high total efficiency the U-235 capture and fission cross-sections, disentangling accurately the two types of reactions. The work presented here proves that accurate capture cross-section measurements of fissile isotopes are feasible at nTOF.
|
|
|
|
Guerrero, C., Domingo-Pardo, C., Kappeler, F., Lerendegui-Marco, J., Palomo, F. R., Quesada, J. M., et al. (2017). Prospects for direct neutron capture measurements on s-process branching point isotopes. Eur. Phys. J. A, 53(5), 87–5pp.
Abstract: The neutron capture cross sections of several unstable key isotopes acting as branching points in the s-process are crucial for stellar nucleosynthesis studies, but they are very challenging to measure directly due to the difficult production of sufficient sample material, the high activity of the resulting samples, and the actual (n, gamma) measurement, where high neutron fluxes and effective background rejection capabilities are required. At present there are about 21 relevant s-process branching point isotopes whose cross section could not be measured yet over the neutron energy range of interest for astrophysics. However, the situation is changing with some very recent developments and upcoming technologies. This work introduces three techniques that will change the current paradigm in the field: the use of gamma-ray imaging techniques in (n,gamma) experiments, the production of moderated neutron beams using high-power lasers, and double capture experiments in Maxwellian neutron beams.
|
|
|
|
n_TOF Collaboration(Guerrero, C. et al), Domingo-Pardo, C., Giubrone, G., & Tain, J. L. (2013). Performance of the neutron time-of-flight facility n_TOF at CERN. Eur. Phys. J. A, 49(2), 27–15pp.
Abstract: The neutron time-of-flight facility n_TOF features a white neutron source produced by spallation through 20 GeV/c protons impinging on a lead target. The facility, aiming primarily at the measurement of neutron-induced reaction cross sections, was operating at CERN between 2001 and 2004, and then underwent a major upgrade in 2008. This paper presents in detail all the characteristics of the new neutron beam in the currently available configurations, which correspond to two different collimation systems and two choices of neutron moderator. The characteristics discussed include the intensity and energy dependence of the neutron flux, the spatial profile of the beam, the in-beam background components and the energy resolution/broadening. The discussion of these features is based on dedicated measurements and Monte Carlo simulations, and includes estimations of the systematic uncertainties of the mentioned quantities.
|
|
|
|
Guo, F. K., Meissner, U. G., Nieves, J., & Yang, Z. (2016). Remarks on the P-c structures and triangle singularities. Eur. Phys. J. A, 52(10), 318–6pp.
Abstract: It was proposed that the narrow P-c(4450) structure observed by the LHCb Collaboration in the reaction Lambda(b) -> J/psi pK might be due to a triangle singularity around the chi(c1)-proton threshold at 4.45 GeV. We discuss the occurrence of a similar triangle singularity in the J/psi p invariant mass distribution for the decay Lambda(b) -> J/psi p pi, which could explain the bump around 4.45 GeV in the data. More precise measurements of this process would provide valuable information towards an understanding of the P-c structures.
|
|
|
|
R3B Collaboration(Heil, M. et al), & Nacher, E. (2022). A new Time-of-flight detector for the (RB)-B-3 setup. Eur. Phys. J. A, 58(12), 248–19pp.
Abstract: We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R3B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision sigma_Delta E/Delta E of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.
|
|
|
|
Huyuk, T. et al, Gadea, A., Aliaga-Varea, R. J., & Domingo-Pardo, C. (2016). Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA. Eur. Phys. J. A, 52(3), 55–8pp.
Abstract: The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large gamma-ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23 l and it is filled with the EJ301 liquid scintillator, that presents good neutron-gamma discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the Ni-58 + Fe-56 reaction measured with the Neutron Wall detector array.
|
|
|
|
Ikeno, N., Dai, L. R., & Oset, E. (2020). Meson exchange between initial and final state and the R-D ratio in the B-bar -> D nu-bar l (nu_tau-bar tau) reactions. Eur. Phys. J. A, 56(2), 73–12pp.
Abstract: We perform a calculation of the strong interaction effects between the B and D mesons in the B -> D nu l reaction, as a crossing process of reactions with BD in the final state, where the strong interaction between the mesons leads to a bound BD state. We find corrections to the tree level amplitude of the order of 15-25%. We further see the effect of the corrections studied in the R-D ratio for the rates of B -> D nu and B. D decays and find corrections of the order of 10%. Given the claims of 1.5% precision in this ratio from fits to data within the standardmodel, any theoretical model aiming at describing this ratio within the same precision must take into account the corrections described in the present work.
|
|
