921 research outputs found
Two Proton Emission with Electromagnetic Probes
A model to study two-proton emission from nuclei induced by electromagnetic
probes is developed. The process is due to one-body electromagnetic operators,
acting together with short-range correlations, and two-body currents.
The model includes all the diagrams containing a single correlation function.
The sensitivity of the cross section to the details of the correlation function
is studied by using realistic and schematic correlations. Results for the
O nucleus are presented.Comment: 9 pages, 8 figures, Contribution to the 6th. Workshop on
"Electromagnetic Induced Two-Hadron Emission",Pavia, 200
Photo-emission of two protons from nuclei
The photo-emission of two protons from the C, O and Ca
nuclei is investigated. Aim of the work is the study of the possibilities
offered by this probe to obtain information about the characteristics of the
short-range correlations. We have also evaluated the effects of the two-body
-currents which, in this processes, compete with those produced by the
short-range correlations. Our results show that (,pp) processes could
be more useful than (e,e'pp) for the study of the short-range correlations.Comment: 21 pages, 15 figures, 3 table
Finite-range simple effective interaction including tensor terms
ACKNOWLEDGMENTS
Useful discussions with F. Stancu are warmly acknowledged.
P. Bano acknowledges the support from MANF
Fellowship of UGC, India. T.R.R. gives sincere thanks to Professor
B. Behera for meaningful discussions. M.C. and X.V.
were partially supported by Grants No. PID2020-118758GBI00
and No. CEX2019-000918-M (through the “Unit of
Excellence María de Maeztu 2020-2023” award to ICCUB)
from the Spanish MCIN/AEI (DOI 10.13039/501100011033).
The work of L.M.R. was partly supported by the Spanish
MINECO Grant No. PGC2018-094583-B-I00. M.A. has
been partially supported by the Spanish MINECO Grant No.
PID2019-104888GB-I00.An existing parametrization of the simple effective interaction (SEI) that is able to reproduce the experimentally known crossing between the 2p3/2 and 1f5/2 single-particle (s.p.) proton levels in neutron-rich Ni isotopes has been generalized. We have added a short-range tensor force in order to describe the observed gaps between the 1h11/2 and 1g7/2s.p. proton levels in the Sn isotopic chain and between the 1i13/2 and 1h9/2s.p. neutron levels in N=82 isotones without compromising the good agreement with the splittings in the Ni isotopes. Different scenarios where tensor effects are relevant are considered with the new interaction and its predictions are compared with results from other mean-field models and experimental data where available.MANF Fellowship of UGCUniversity Grants Commission
CEX2019-000918-M, PID2020-118758GB-I00Ministerio de Economía y Competitividad
PGC2018-094583-B-I00, PID2019-104888GB-I00Agencia Estatal de InvestigaciónInstituto de Ciencias del Cosmos, Universitat de Barcelona (ICCUB
Una breve storia della radioterapia. A brief history of radiotherapy
Questo articolo delinea le pietre miliari dello sviluppo della radioterapia sin dai suoi inizi. In particolare, descrive come alcune delle differenti tecniche sviluppate e usate in più di 100 anni di storia sono diventate prassi comune: dalle molteplici applicazioni dei raggi X, utilizzati solo pochi mesi dopo la loro scoperta, che hanno definito l'inizio delle radiazioni ionizzanti nella terapia contro il cancro, fino alla più recente adroterapia. Sono citate le persone che hanno reso possibili questi sviluppi
Tensor and tensor-isospin terms in the effective Gogny interaction
We discuss the need of including tensor terms in the effective Gogny
interaction used in mean-field calculations. We show in one illustrative case
that, with the usual tensor term that is employed in the Skyrme interaction
(and that allows us to separate the like-nucleon and the neutron-proton tensor
contributions), we can describe the evolution of the N=28 neutron gap in
calcium isotopes. We propose to include a tensor and a tensor-isospin term in
finite-range interactions of Gogny type. The parameters of the two tensor terms
allow us to treat separately the like-nucleon and the neutron-proton
contributions. Two parameterizations of the tensor terms have been chosen to
reproduce different neutron single-particle properties in the 48Ca nucleus and
the energy of the first 0- state in the 16O nucleus. By employing these two
parameterizations we analyze the evolution of the N=14, 28, and 90 neutron
energy gaps in oxygen, calcium and tin isotopes, respectively. We show that the
combination of the parameters governing the like-nucleon contribution is
crucial to correctly reproduce the experimental (where available) or
shell-model trends for the evolution of the three neutron gaps under study.Comment: 20 pages, 6 figures. Accepted for publication in Physical Review
Effect of short- and long-range correlations on neutron skins of various neutron-rich doubly magic nuclei
We study the effects of correlations beyond the independent particle model in the evaluation of neutron skins of
various neutron-rich doubly magic nuclei.We consider short- and long-range correlations to take into account the
presence of the strongly repulsive core of the bare nucleon-nucleon interaction and collective nuclear phenomena,
respectively. Despite the strong sensitivity on the structure of the nucleus considered, our results indicate that, in
general, correlations increase the values of the neutron skins.Junta de Andalucia FQM387Spanish Government PID2019-104888GB-I00European Commissio
Effective tensor forces and neutron rich nuclei
We study the effects of the tensor term of the effective nucleon-nucleon
interaction on nuclear excited states. Our investigation has been conducted by
using a self-consistent Random Phase Approximation approach. We investigate
various nuclei in different regions of the isotopes chart. Results for a set of
calcium isotopes are shown.Comment: 4 pages, 4 figures, 1 table Proc. 10th International Spring Seminar
on Nuclear Physics New Quests in Nuclear Structure, Vietri Sul Mare, May
21-25, 201
L'editoria scientifica: un labirinto senza uscita?
ItQuesto articolo presenta alcuni aneddoti relativi al processo di pubblicazione scientifica riguardanti autori, revisori ed editori, aneddoti nei quali siamo stati personalmente coinvolti. Cerchiamo di evidenziare il fatto che i problemi messi in evidenza, a nostro avviso, sono dovuti all'inflazione di articoli causata dalla quantificazione a cui ci ha portato da qualche anno l'uso quasi esclusivo degli indici bibliometrici nella valutazione dei curricula. Il nostro obiettivo è quello di promuovere la discussione sul tema e, pur non indicando possibili soluzioni, dato che purtroppo non le abbiamo, indichiamo alcune prime azioni che potrebbero riorientare la situazione.EsEn este artículo se exponen algunas anécdotas relacionadas con el proceso de publicación científica que atañen a autores, revisores y editores y de las que hemos sido partícipes personalmente. Tratamos de resaltar el hecho de que, en nuestra opinión, son debidas a la inflación de artículos provocada por la cuantificación a la que el uso casi exclusivo de los índices bibliométricos en la evaluación curricular nos ha abocado desde hace ya algunos años. Nuestro objetivo es promover la discusión al respecto y, aunque no se indican posibles soluciones, dado que, por desgracia, no disponemos de ellas, se indican algunas acciones iniciales que podrían reconducir la situación
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