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Author Olmo, G.J.; Rubiera-Garcia, D.; Wojnar, A.
Title (down) Stellar structure models in modified theories of gravity: Lessons and challenges Type Journal Article
Year 2020 Publication Physics Reports Abbreviated Journal Phys. Rep.
Volume 876 Issue Pages 1-75
Keywords Stellar structure; Modified gravity; Palatini formalism; Neutron stars; Brown dwarfs; Relativistic stars; Weak field; f(R) theories; Born-Infeld theory; Horndeski theory
Abstract The understanding of stellar structure represents the crossroads of our theories of the nuclear force and the gravitational interaction under the most extreme conditions observably accessible. It provides a powerful probe of the strong field regime of General Relativity, and opens fruitful avenues for the exploration of new gravitational physics. The latter can be captured via modified theories of gravity, which modify the Einstein-Hilbert action of General Relativity and/or some of its principles. These theories typically change the Tolman-Oppenheimer-Volkoff equations of stellar's hydrostatic equilibrium, thus having a large impact on the astrophysical properties of the corresponding stars and opening a new window to constrain these theories with present and future observations of different types of stars. For relativistic stars, such as neutron stars, the uncertainty on the equation of state of matter at supranuclear densities intertwines with the new parameters coming from the modified gravity side, providing a whole new phenomenology for the typical predictions of stellar structure models, such as mass-radius relations, maximum masses, or moment of inertia. For non-relativistic stars, such as white, brown and red dwarfs, the weakening/strengthening of the gravitational force inside astrophysical bodies via the modified Newtonian (Poisson) equation may induce changes on the star's mass, radius, central density or luminosity, having an impact, for instance, in the Chandrasekhar's limit for white dwarfs, or in the minimum mass for stable hydrogen burning in high-mass brown dwarfs. This work aims to provide a broad overview of the main such results achieved in the recent literature for many such modified theories of gravity, by combining the results and constraints obtained from the analysis of relativistic and non-relativistic stars in different scenarios. Moreover, we will build a bridge between the efforts of the community working on different theories, formulations, types of stars, theoretical modelings, and observational aspects, highlighting some of the most promising opportunities in the field.
Address [Olmo, Gonzalo J.] Univ Valencia, Dept Fis Teor, Ctr Mixto, CSIC, Valencia 46100, Spain, Email: gonzalo.olmo@uv.es;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-1573 ISBN Medium
Area Expedition Conference
Notes WOS:000570298900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4531
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Author n_TOF Collaboration (Patronis, N. et al); Babiano-Suarez, V.; Balibrea Correa, J.; Domingo-Pardo, C.; Ladarescu, I.; Lerendegui-Marco, J.
Title (down) Status report of the n_TOF facility after the 2nd CERN long shutdown period Type Journal Article
Year 2023 Publication EPJ Techniques and Instrumentation Abbreviated Journal EPJ Tech. Instrum.
Volume 10 Issue 1 Pages 13 - 10pp
Keywords Neutron time of flight; Spallation target; Nuclear astrophysics; Neutron physics; Neutron induced fission; Neutron reactions
Abstract During the second long shutdown period of the CERN accelerator complex (LS2, 2019-2021), several upgrade activities took place at the nTOF facility. The most important have been the replacement of the spallation target with a next generation nitrogen-cooled lead target. Additionally, a new experimental area, at a very short distance from the target assembly (the NEAR Station) was established. In this paper, the core commissioning actions of the new installations are described. The improvement in the nTOF infrastructure was accompanied by several detector development projects. All these upgrade actions are discussed, focusing mostly on the future perspectives of the n_TOF facility. Furthermore, some indicative current and future measurements are briefly reported.
Address [Patronis, N.; Goula, S.; Eleme, Z.; Stamati, M. E.; Vagena, E.] Univ Ioannina, Ioannina, Greece, Email: nikolaos.patronis@cern.ch
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2195-7045 ISBN Medium
Area Expedition Conference
Notes WOS:001008786600001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5591
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Author Ding, G.J.; Nath, N.; Srivastava, R.; Valle, J.W.F.
Title (down) Status and prospects of 'bi-large' leptonic mixing Type Journal Article
Year 2019 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 796 Issue Pages 162-167
Keywords
Abstract Bi-large patterns for the leptonic mixing matrix are confronted with current neutrino oscillation data. We analyse the status of these patterns and determine, through realistic simulations, the potential of the upcoming long-baseline experiment DUNE in testing bi-large ansatze and discriminating amongst them.
Address [Ding, Gui-Jun] Univ Sci & Technol China, Interdisciplinary Ctr Theoret Study, Hefei 230026, Anhui, Peoples R China, Email: dinggj@ustc.edu.cn;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:000483426200024 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4132
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Author Coloma, P.; Huber, P.; Schwetz, T.
Title (down) Statistical interpretation of sterile neutrino oscillation searches at reactors Type Journal Article
Year 2021 Publication European Physical Journal C Abbreviated Journal Eur. Phys. J. C
Volume 81 Issue 1 Pages 2 - 13pp
Keywords
Abstract A considerable experimental effort is currently under way to test the persistent hints for oscillations due to an eV-scale sterile neutrino in the data of various reactor neutrino experiments. The assessment of the statistical significance of these hints is usually based on Wilks' theorem, whereby the assumption is made that the log-likelihood is chi 2-distributed. However, it is well known that the preconditions for the validity of Wilks' theorem are not fulfilled for neutrino oscillation experiments. In this work we derive a simple asymptotic form of the actual distribution of the log-likelihood based on reinterpreting the problem as fitting white Gaussian noise. From this formalism we show that, even in the absence of a sterile neutrino, the expectation value for the maximum likelihood estimate of the mixing angle remains non-zero with attendant large values of the log-likelihood. Our analytical results are then confirmed by numerical simulations of a toy reactor experiment. Finally, we apply this framework to the data of the Neutrino-4 experiment and show that the null hypothesis of no-oscillation is rejected at the 2.6 sigma level, compared to 3.2 sigma obtained under the assumption that Wilks' theorem applies.
Address [Coloma, Pilar] Univ Autonoma Madrid, CSIC, Inst Fis Teor UAM, Calle Nicolas Cabrera 13-15, Madrid 28049, Spain, Email: pilar.coloma@ift.csic.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1434-6044 ISBN Medium
Area Expedition Conference
Notes WOS:000606481000002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4680
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Author Foffa, S.; Mastrolia, P.; Sturani, R.; Sturm, C.; Bobadilla, W.J.T.
Title (down) Static Two-Body Potential at Fifth Post-Newtonian Order Type Journal Article
Year 2019 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 122 Issue 24 Pages 241605 - 6pp
Keywords
Abstract We determine the gravitational interaction between two compact bodies up to the sixth power in Newton's constant, G(N), in the static limit. This result is achieved within the effective field theory approach to general relativity, and exploits a manifest factorization property of static diagrams which allows us to derive static post Newtonian (PN) contributions of (2n + 1) order in terms of lower order ones. We recompute in this fashion the 1PN and 3PN static potential, and present the novel 5PN contribution.
Address [Foffa, Stefano] Univ Geneva, Dept Phys Theor, CH-1211 Geneva, Switzerland
Corporate Author Thesis
Publisher Amer Physical Soc Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0031-9007 ISBN Medium
Area Expedition Conference
Notes WOS:000473033800003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4070
Permanent link to this record