Records |
Author |
Feijoo, A.; Gazda, D.; Magas, V.; Ramos, A. |
Title |
The (K)over-barN Interaction in Higher Partial Waves |
Type |
Journal Article |
Year |
2021 |
Publication |
Symmetry-Basel |
Abbreviated Journal |
Symmetry-Basel |
Volume |
13 |
Issue |
8 |
Pages |
1434 - 22pp |
Keywords |
chiral Lagrangian; unitarization; resonances; (K)over-barN interaction |
Abstract |
We present a chiral (K) over barN interaction model that has been developed and optimized in order to account for the experimental data of inelastic (K) over barN reaction channels that open at higher energies. In particular, we study the effect of the higher partial waves, which originate directly from the chiral Lagrangian, as they could supersede the role of high-spin resonances employed in earlier phenomenological models to describe meson-baryon cross sections in the 2 GeV region. We present a detailed derivation of the partial wave amplitudes that emerge from the chiral SU(3) meson-baryon Lagrangian up to the d-waves and next-to-leading order in the chiral expansion. We implement a nonperturbative unitarization in coupled channels and optimize the model parameters to a large pool of experimental data in the relevant energy range where these new contributions are expected to be important. The obtained results are encouraging. They indicate the ability of the chiral higher partial waves to extend the description of the scattering data to higher energies and to account for structures in the reaction cross-sections that cannot be accommodated by theoretical models limited to the s-waves. |
Address |
[Feijoo, Albert] Ctr Mixto CSIC UV, Inst Fis Corpuscular, Inst Invest Paterna, Apartados 22085, Valencia 46071, Spain, Email: edfeijoo@ific.uv.es; |
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Publisher |
Mdpi |
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English |
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Notes |
WOS:000689831200001 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4948 |
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Author |
Dorigo, T. et al; Ramos, A.; Ruiz de Austri, R. |
Title |
Toward the end-to-end optimization of particle physics instruments with differentiable programming |
Type |
Journal Article |
Year |
2023 |
Publication |
Reviews in Physics |
Abbreviated Journal |
Rev. Phys. |
Volume |
10 |
Issue |
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Pages |
100085 - pp |
Keywords |
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Abstract |
The full optimization of the design and operation of instruments whose functioning relies on the interaction of radiation with matter is a super-human task, due to the large dimensionality of the space of possible choices for geometry, detection technology, materials, data-acquisition, and information-extraction techniques, and the interdependence of the related parameters. On the other hand, massive potential gains in performance over standard, “experience-driven” layouts are in principle within our reach if an objective function fully aligned with the final goals of the instrument is maximized through a systematic search of the configuration space. The stochastic nature of the involved quantum processes make the modeling of these systems an intractable problem from a classical statistics point of view, yet the construction of a fully differentiable pipeline and the use of deep learning techniques may allow the simultaneous optimization of all design parameters. |
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Area |
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Expedition |
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Notes |
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Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
6096 |
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Author |
Sekihara, T.; Oset, E.; Ramos, A. |
Title |
On the structure observed in the in-flight He-3(K-, Lambda p)n reaction at J-PARC |
Type |
Journal Article |
Year |
2016 |
Publication |
Progress of Theoretical and Experimental Physics |
Abbreviated Journal |
Prog. Theor. Exp. Phys. |
Volume |
2016 |
Issue |
12 |
Pages |
123D03 - 27pp |
Keywords |
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Abstract |
A theoretical investigation is done to clarify the origin of the peak structure observed near the K-pp threshold in the in-flight He-3(K-, Lambda p)n reaction of the J-PARC E15 experiment, which could be a signal of the lightest kaonic nuclei, i.e., the (K) over bar NN (I = 1/2) state. For the investigation, we evaluate the Lambda p invariant mass spectrum assuming two possible scenarios to interpret the experimental peak. One assumes that the Lambda (1405) resonance is generated after the emission of an energetic neutron from the absorption of the initial K-, not forming a bound state with the remaining proton. This uncorrelated Lambda (1405)p system subsequently decays into the final Lambda p. The other scenario implies that, after the emission of the energetic neutron, a (K) over bar NN bound state is formed, decaying eventually into a Lambda p pair. Our results show that the experimental signal observed in the in-flight He-3(K-, Lambda p)n reaction at J-PARC is qualitatively well reproduced by the assumption that a (K) over bar NN bound state is generated in the reaction, definitely discarding the interpretation in terms of an uncorrelated Lambda (1405)p s tate. |
Address |
[Sekihara, Takayasu] Japan Atom Energy Agcy, Adv Sci Res Ctr, Tokai, Ibaraki 3191195, Japan, Email: sekihara@post.j-parc.jp |
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Oxford Univ Press Inc |
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English |
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Edition |
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ISSN |
2050-3911 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000393905400018 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
2954 |
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Author |
Hernandez, P.; Pena, C.; Ramos, A.; Gomez-Cadenas, J.J. |
Title |
A new formulation of compartmental epidemic modelling for arbitrary distributions of incubation and removal times |
Type |
Journal Article |
Year |
2021 |
Publication |
Plos One |
Abbreviated Journal |
PLoS One |
Volume |
16 |
Issue |
2 |
Pages |
e0244107 - 22pp |
Keywords |
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Abstract |
The paradigm for compartment models in epidemiology assumes exponentially distributed incubation and removal times, which is not realistic in actual populations. Commonly used variations with multiple exponentially distributed variables are more flexible, yet do not allow for arbitrary distributions. We present a new formulation, focussing on the SEIR concept that allows to include general distributions of incubation and removal times. We compare the solution to two types of agent-based model simulations, a spatially homogeneous one where infection occurs by proximity, and a model on a scale-free network with varying clustering properties, where the infection between any two agents occurs via their link if it exists. We find good agreement in both cases. Furthermore a family of asymptotic solutions of the equations is found in terms of a logistic curve, which after a non-universal time shift, fits extremely well all the microdynamical simulations. The formulation allows for a simple numerical approach; software in Julia and Python is provided. |
Address |
[Hernandez, Pilar] Univ Valencia, Dept Fis Teor, Valencia, Spain, Email: m.pilar.hernandez@uv.es |
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Publisher |
Public Library Science |
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English |
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ISSN |
1932-6203 |
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Conference |
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Notes |
WOS:000616739700053 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number |
IFIC @ pastor @ |
Serial |
4750 |
Permanent link to this record |
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Author |
Feijoo, A.; Magas, V.K.; Ramos, A.; Oset, E. |
Title |
Lambda(b) -> J/psi K Xi decay and the higher order chiral terms of the meson baryon interaction |
Type |
Journal Article |
Year |
2015 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
Volume |
92 |
Issue |
7 |
Pages |
076015 - 10pp |
Keywords |
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Abstract |
We study the weak decay of the Lambda(b) into J/psi K Xi. and J/psi eta Lambda states, and relate these processes to the Lambda(b) -> J/psi(K) over barN decay mode. The elementary weak transition at the quark level proceeds via the creation of a J/psi meson and an excited sud system with I = 0, which upon hadronization leads to (K) over barN or eta Lambda pairs. These states undergo final-state interaction in coupled channels and produce a final meson-baryon pair. The K. state only occurs via rescattering, hence making the Lambda(b) -> J/psi K Xi process very sensitive to the details of the meson-baryon interaction in strangeness S = -1 and isospin I = 0. We show that the corresponding invariant mass distribution is dominated by the next-to-leading-order terms of the chiral interaction. The I = 0 selectivity of this decay, and its large sensitivity to the higher-order terms, makes its measurement very useful and complementary to the K- p -> K Xi cross section data. The rates of the Lambda(b) -> J/psi K Xi and Lambda(b) -> J/psi eta Lambda invariant mass distributions are sizable compared to those of the Lambda(b) -> J/psi(K) over barN decay, which is measured experimentally, and thus, we provide arguments for an experimental determination of these decay modes that will help us understand better the chiral dynamics at higher energies. |
Address |
[Feijoo, A.; Magas, V. K.; Ramos, A.] Univ Barcelona, Dept Estruct & Constituents Mat, E-08028 Barcelona, Spain, Email: feijoo@ecm.ub.edu |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1550-7998 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000363792600009 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
no |
Call Number |
IFIC @ pastor @ |
Serial |
2432 |
Permanent link to this record |