8 results on '"Rida Khalifeh, A."'
Search Results
2. Distinguishing Dark Energy Models with Neutrino Oscillations
- Author
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Ali Rida Khalifeh and Raul Jimenez
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Physics ,Particle physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Cosmological constant ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Redshift ,Coupling (physics) ,General Relativity and Quantum Cosmology ,High Energy Physics - Phenomenology ,High Energy Physics - Phenomenology (hep-ph) ,Space and Planetary Science ,Spinor field ,Dark energy ,High Energy Physics::Experiment ,Neutrino ,Neutrino oscillation ,Scalar field ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Dark Energy models are numerous and distinguishing between them is becoming difficult. However, using distinct observational probes can ease this quest and gives better assessment to the nature of Dark energy. To this end, the plausibility of neutrino oscillations to be a probe of Dark Energy models is investigated. First, a generalized formalism of neutrino (spinor field) interaction with a classical scalar field in curved space-time is presented. This formalism is then applied to two classes of Dark Energy models in a flat Friedman-Lema\^itre-Robertson-Walker metric: a Cosmological Constant and scalar field Dark Energy coupled to neutrinos. By looking at the neutrino oscillation probability's evolution with redshift, these models can be distinguished, for certain neutrino and scalar field coupling properties. This evolution could be traced by neutrino flux in future underground, terrestrial or extraterrestrial neutrino telescopes, which would assess probing Dark Energy models with this technique., Comment: 25 pages, 3 figures. Matching published version in Physics of the Dark Universe
- Published
- 2021
3. EuCAPT White Paper: Opportunities and Challenges for Theoretical Astroparticle Physics in the Next Decade
- Author
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Alves Batista, R., Amin, M. A., Barenboim, G., Bartolo, N., Baumann, D., Bauswein, A., Bellini, E., Benisty, D., Bertone, G., Blasi, P., Böhmer, C. G., Bošnjak, Ž., Bringmann, T., Burrage, C., Bustamante, M., Calderón Bustillo, J., Byrnes, C. T., Calore, F., Catena, R., Cerdeño, D. G., Cerri, S. S., Chianese, M., Clough, K., Cole, A., Coloma, P., Coogan, A., Covi, L., Cutting, D., Davis, A. C., Rham, C. de, Matteo, A. di, Domènech, G., Drewes, M., Dietrich, T., Edwards, T. D. P., Esteban, I., Erdem, R., Evoli, C., Fasiello, M., Feeney, S. M., Ferreira, R. Z., Fialkov, A., Fornengo, N., Gabici, S., Galatyuk, T., Gaggero, D., Grasso, D., Guépin, C., Harz, J., Herrero-Valea, M., Hinderer, T., Hogg, N. B., Hooper, D. C., Iocco, D., Isern, J., Karchev, K., Kavanagh, B. J., Korsmeier, M., Kotera, K., Koyama, K., Krishnan, B., Lesgourgues, J., Levi Said, J., Lombriser, L., Lorenz, C. S., Manconi, S., Mapelli, M., Marcowith, A., Markoff, S. B., Marsh, D. J., Martinelli, M., Martinsolami, C. J. A. P., Millington, P., Moesta, P., Nippel, K., Niro, V., O'Connor, E., Oikonomou, F., Paganini, C. F., Pagliaroli, G., P. Pani, P., Pfrommer, C., Pascoli, S., Pinol, L., Pizzuti, L., Porto, R. A., Pound, A., Quevedo, F., Raffelt, G. G., Raccanelli, A., Ramirez-Ruiz, E., Raveri, M., Renaux-Petel, S., Ricciardone, A., Rida Khalifeh, A., Riotto, A., Roiban, R., Rubio, J., Sahlén, M., Sabti, N., Sagunski, L., Šarčević, N., Schmitz, K., Schwaller, P., Schwetz, T., Sedrakian, A., Sellentin, E., Serenelli, A., Serpico, P. D., Sfakianakis, E. I., Shalgar, S., Silvestri, A., Tamborra, I., Tanidis, K., Teresi, D., Tokareva, A. A., Tolos, L., Trojanowski, S., Trotta, R., Uhlemann, C., Urban, F. R., Vernizzi, F., Vliet, A. van, Villante, F. L., Vincent, A., Vink, J., Vitagliano, E., Weniger, C., Wickenbrock, A., Winter, W., Zell, S., and Zeng, M.
- Subjects
Physics ,ddc:530 - Published
- 2021
- Full Text
- View/download PDF
4. EuCAPT White Paper : Opportunities and Challenges for Theoretical Astroparticle Physics in the Next Decade
- Author
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Alves-Batista, R., Amin, M. A., Barenboim, G., Bartolo, N., Baumann, D., Bauswein, A., Bellini, E., Benisty, D., Bertone, G., Blasi, P., Böhmer, C. G., Bošnjak, Ž, Bringmann, T., Burrage, C., Bustamante, M., Calderón Bustillo, J., Byrnes, C. T., Calore, F., Catena, R., Cerdeño, D. G., Cerri, S. S., Chianese, M., Clough, K., Cole, A., Coloma, P., Coogan, A., Covi, L., Cutting, D., Davis, A. C., de Rham, C., di Matteo, A., Domènech, G., Drewes, M., Dietrich, T., Edwards, T. D. P., Esteban, I., Erdem, R., Evoli, C., Fasiello, M., Feeney, S. M., Ferreira, R. Z., Fialkov, A., Fornengo, N., Gabici, S., Galatyuk, T., Gaggero, D., Grasso, D., Guépin, C., Harz, J., Herrero-Valea, M., Hinderer, T., Hogg, N. B., Hooper, D. C., Iocco, F., Isern, J., Karchev, K., Kavanagh, B. J., Korsmeier, M., Kotera, K., Koyama, K., Krishnan, B., Lesgourgues, J., Levi Said, J., Lombriser, L., Lorenz, C. S., Manconi, S., Mapelli, M., Marcowith, A., Markoff, S. B., Marsh, D. J. E., Martinelli, M., Martins, C. J. A. P., Matthews, J. H., Meli, A., Mena, O., Mifsud, J., Miller Bertolami, M. M., Millington, P., Moesta, P., Nippel, K., Niro, V., O’Connor, E., Oikonomou, F., Paganini, C. F., Pagliaroli, G., Pani, P., Pfrommer, C., Pascoli, S., Pinol, L., Pizzuti, L., Porto, R. A., Pound, A., Quevedo, F., Raffelt, G. G., Raccanelli, A., Ramirez-Ruiz, E., Raveri, M., Renaux-Petel, S., Ricciardone, A., Rida Khalifeh, A., Riotto, A., Roiban, R., Rubio, J., Sahlén, M., Sabti, N., Sagunski, L., Šarčević, N., Schmitz, K., Schwaller, P., Schwetz, T., Sedrakian, A., Sellentin, E., Serenelli, A., Serpico, P. D., Sfakianakis, E. I., Shalgar, S., Silvestri, A., Tamborra, I., Tanidis, K., Teresi, D., Tokareva, A. A., Tolos, L., Trojanowski, S., Trotta, R., Uhlemann, C., Urban, F. R., Vernizzi, F., van Vliet, A., Villante, F. L., Vincent, A., Vink, J., Vitagliano, E., Weniger, C., Wickenbrock, A., Winter, W., Zell, S., Zeng, M., Alves-Batista, R., Amin, M. A., Barenboim, G., Bartolo, N., Baumann, D., Bauswein, A., Bellini, E., Benisty, D., Bertone, G., Blasi, P., Böhmer, C. G., Bošnjak, Ž, Bringmann, T., Burrage, C., Bustamante, M., Calderón Bustillo, J., Byrnes, C. T., Calore, F., Catena, R., Cerdeño, D. G., Cerri, S. S., Chianese, M., Clough, K., Cole, A., Coloma, P., Coogan, A., Covi, L., Cutting, D., Davis, A. C., de Rham, C., di Matteo, A., Domènech, G., Drewes, M., Dietrich, T., Edwards, T. D. P., Esteban, I., Erdem, R., Evoli, C., Fasiello, M., Feeney, S. M., Ferreira, R. Z., Fialkov, A., Fornengo, N., Gabici, S., Galatyuk, T., Gaggero, D., Grasso, D., Guépin, C., Harz, J., Herrero-Valea, M., Hinderer, T., Hogg, N. B., Hooper, D. C., Iocco, F., Isern, J., Karchev, K., Kavanagh, B. J., Korsmeier, M., Kotera, K., Koyama, K., Krishnan, B., Lesgourgues, J., Levi Said, J., Lombriser, L., Lorenz, C. S., Manconi, S., Mapelli, M., Marcowith, A., Markoff, S. B., Marsh, D. J. E., Martinelli, M., Martins, C. J. A. P., Matthews, J. H., Meli, A., Mena, O., Mifsud, J., Miller Bertolami, M. M., Millington, P., Moesta, P., Nippel, K., Niro, V., O’Connor, E., Oikonomou, F., Paganini, C. F., Pagliaroli, G., Pani, P., Pfrommer, C., Pascoli, S., Pinol, L., Pizzuti, L., Porto, R. A., Pound, A., Quevedo, F., Raffelt, G. G., Raccanelli, A., Ramirez-Ruiz, E., Raveri, M., Renaux-Petel, S., Ricciardone, A., Rida Khalifeh, A., Riotto, A., Roiban, R., Rubio, J., Sahlén, M., Sabti, N., Sagunski, L., Šarčević, N., Schmitz, K., Schwaller, P., Schwetz, T., Sedrakian, A., Sellentin, E., Serenelli, A., Serpico, P. D., Sfakianakis, E. I., Shalgar, S., Silvestri, A., Tamborra, I., Tanidis, K., Teresi, D., Tokareva, A. A., Tolos, L., Trojanowski, S., Trotta, R., Uhlemann, C., Urban, F. R., Vernizzi, F., van Vliet, A., Villante, F. L., Vincent, A., Vink, J., Vitagliano, E., Weniger, C., Wickenbrock, A., Winter, W., Zell, S., and Zeng, M.
- Published
- 2021
- Full Text
- View/download PDF
5. Dwarf Galaxies without Dark Matter: constraints on Modified Gravity
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Ali Rida Khalifeh and Raul Jimenez
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Physics ,Gravity (chemistry) ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Dark matter ,FOS: Physical sciences ,Astronomy and Astrophysics ,General Relativity and Quantum Cosmology (gr-qc) ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Virial theorem ,Galaxy ,Cosmology ,General Relativity and Quantum Cosmology ,Standard Model ,Gravitation ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Galaxy Astrophysics ,Dwarf galaxy ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The discovery of $19$ dwarf galaxies without dark matter provides, counter-intuitively, strong support for the $\Lambda$CDM standard model of cosmology. Their presence is well accommodated in a scenario where the dark matter is in the form of cold dark particles. However, it is interesting to explore quantitatively what is needed from modified gravity models to accommodate the presence of these galaxies and what extra degree of freedom is needed in these models. To this end, we derive the dynamics at galaxy scales (Virial theorem) for a general class of modified gravity models. We distinguish between theories that satisfy the Jebsen-Birkhoff theorem, and those that don't. Our aim is to develop tests that can distinguish whether dark matter is part of the theory of gravity or a particle. The 19 dwarf galaxies discovered provide us with a stringent test for models of modified gravity. Our main finding is that there will always be an extra contribution to the Virial theorem coming from the modification of gravity, even if a certain galaxy shows very small, if not negligible, trace of dark matter, as has been reported recently. Thus, if these and more galaxies are confirmed as devoid (or negligible) of dark matter, while other similar galaxies have abundant dark matter, it seems interesting to find modifications of gravity to describe dark matter. Our result can be used by future astronomical surveys to put constraints on the parameters of modified gravity models at astrophysical scales where dark matter is described as such., Comment: Matches accepted version in MNRAS. Extended analysis of the 19 dwarf galaxies without dark matter which shows need for fine tuning in MG. Particle CDM is the best fit to data
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- 2019
6. Can Dark Matter be Geometry? A Case Study with Mimetic Dark Matter
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Nicola Bellomo, José Luis Bernal, Ali Rida Khalifeh, and Raul Jimenez
- Subjects
Physics ,High Energy Physics - Theory ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,010308 nuclear & particles physics ,General relativity ,Matter power spectrum ,Dark matter ,Cosmic microwave background ,FOS: Physical sciences ,Astronomy and Astrophysics ,Observable ,General Relativity and Quantum Cosmology (gr-qc) ,01 natural sciences ,General Relativity and Quantum Cosmology ,Theoretical physics ,High Energy Physics - Theory (hep-th) ,Space and Planetary Science ,0103 physical sciences ,Cosmological perturbation theory ,Perturbation theory (quantum mechanics) ,Adiabatic process ,010303 astronomy & astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We investigate the possibility of dark matter being a pure geometrical effect, rather than a particle or a compact object, by exploring a specific modified gravity model: mimetic dark matter. We present an alternative formulation of the theory, closer to the standard cosmological perturbation theory framework. We make manifest the presence of arbitrary parameters and extra functions, both at background level and at first order in perturbation theory. We present the full set of independent equations of motion for this model, and we discuss the amount of tuning needed to match predictions of the theory to actual data. By using the matter power spectrum and cosmic microwave background angular power spectra as benchmark observables, we explicitly show that since there is no natural mechanism to generate adiabatic initial conditions in this specific model, extra fine-tuning is required. We modify the publicly available Boltzmann code \texttt{CLASS} to make accurate predictions for the observables in mimetic dark matter. Our modified version of \texttt{CLASS} is available on GitHub. We have used mimetic dark matter as an illustration of how much one is allowed to change the initial conditions before contradicting observations when modifying the laws of gravity as described by General Relativity but we point out that modifying gravity without providing a natural mechanism to generate adiabatic initial conditions will always lead to highly fine-tuned models., Matches published version; results unchanged
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- 2019
7. Spinors and Scalars in curved spacetime: Neutrino dark energy (DEν)
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Raul Jimenez and Ali Rida Khalifeh
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Physics ,010308 nuclear & particles physics ,Physics beyond the Standard Model ,Operator (physics) ,Astronomy and Astrophysics ,01 natural sciences ,Gravitation ,Theoretical physics ,Space and Planetary Science ,0103 physical sciences ,Dark energy ,Neutrino ,Neutrino oscillation ,010303 astronomy & astrophysics ,Scalar field ,Curved space - Abstract
We study the interaction, in general curved spacetime, between a spinor and a scalar field describing dark energy; the so-called DE ν model in curved space. The dominant term is the dimension 5 operator, which results in different energy shifts for the neutrino states: an Aharonov–Bohm-like effect. We study the phenomenology of this term and make observational predictions to detect dark energy interactions in the laboratory due to its effect on neutrino oscillation experiments, which opens up the possibility of designing underground experiments to detect dark energy. This dimension 5 operator beyond the Standard Model interaction is less suppressed than the widely discussed dimension 6 operator, which corresponds to mass varying neutrinos; the dimension 5 operator does not suffer from gravitational instabilities.
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- 2021
- Full Text
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8. Measuring the homogeneity of the universe using polarization drift
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Robert R. Caldwell, Roy Maartens, Ali Rida Khalifeh, Licia Verde, Raul Jimenez, and Alan Heavens
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High Energy Physics - Theory ,CMBR polarisation ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Photon ,gr-qc ,media_common.quotation_subject ,Cosmic microwave background ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astronomy & Astrophysics ,01 natural sciences ,General Relativity and Quantum Cosmology ,Physics, Particles & Fields ,0201 Astronomical and Space Sciences ,0103 physical sciences ,physics of the early universe ,STFC ,Sunyaev-Zeldovich effect ,media_common ,Physics ,Science & Technology ,010308 nuclear & particles physics ,hep-th ,Isotropy ,RCUK ,Astronomy and Astrophysics ,Observable ,Polarization (waves) ,Nuclear & Particles Physics ,Universe ,Computational physics ,High Energy Physics - Theory (hep-th) ,Physical Sciences ,0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics ,astro-ph.CO ,Dark energy ,DARK ENERGY ,ST/N000668/1 ,Baryon acoustic oscillations ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We propose a method to probe the homogeneity of a general universe, without assuming symmetry. We show that isotropy can be tested at remote locations on the past lightcone by comparing the line-of-sight and transverse expansion rates, using the time dependence of the polarization of Cosmic Microwave Background photons that have been inverse-Compton scattered by the hot gas in massive clusters of galaxies. This probes a combination of remote transverse and parallel components of the expansion rate of the metric, and we may use radial baryon acoustic oscillations or cosmic clocks to measure the parallel expansion rate. Thus we can test remote isotropy, which is a key requirement of a homogeneous universe. We provide explicit formulas that connect observables and properties of the metric., Matches accepted version to JCAP; conclusions unchanged; now includes detailed section of the expected S/N of the signal
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- 2019
- Full Text
- View/download PDF
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