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Author |
Ellis, J.; Konoplich, R.; Mavromatos, N.E.; Nguyen, L.; Sakharov, A.S.; Sarkisyan-Grinbaum, E.K. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Robust constraint on Lorentz violation using Fermi-LAT gamma-ray burst data |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
99 |
Issue ![sorted by Issue field, descending order (down)](img/sort_desc.gif) |
8 |
Pages |
083009 - 22pp |
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Abstract |
Models of quantum gravity suggest that the vacuum should be regarded as a medium with quantum structure that may have nontrivial effects on photon propagation, including the violation of Lorentz invariance. Fermi Large Area Telescope (LAT) observations of gamma-ray bursts (GRBs) are sensitive probes of Lorentz invariance, via studies of energy-dependent timing shifts in their rapidly varying photon emissions. We analyze the Fermi-LAT measurements of high-energy gamma rays from GRBs with known redshifts, allowing for the possibility of energy-dependent variations in emission times at the sources as well as a possible nontrivial refractive index in vacuo for photons. We use statistical estimators based on the irregularity, kurtosis, and skewness of bursts that are relatively bright in the 100 MeV to multi-GeV energy band to constrain possible dispersion effects during propagation. We find that the energy scale characterizing a linear energy dependence of the refractive index should exceed a few x10(17) GeV, and we estimate the sensitivity attainable with additional future sources to be detected by Fermi-LAT. |
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Address |
[Ellis, John; Mavromatos, Nikolaos E.] Kings Coll London, Dept Phys, Theoret Particle Phys & Cosmol Grp, London WC2R 2LS, England |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
2470-0010 |
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Notes |
WOS:000464745800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3982 |
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Author |
Fioresi, R.; Latini, E.; Lledo, M.A.; Nadal, F.A. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
The Segre embedding of the quantum conformal superspace |
Type |
Journal Article |
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Year |
2018 |
Publication |
Advances in Theoretical and Mathematical Physics |
Abbreviated Journal |
Adv. Theor. Math. Phys. |
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Volume |
22 |
Issue ![sorted by Issue field, descending order (down)](img/sort_desc.gif) |
8 |
Pages |
1939-2000 |
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Abstract |
In this paper we study the quantum deformation of the superflag Fl(2 vertical bar 0, 2 vertical bar 1, 4 vertical bar 1), and its big cell, describing the complex conformal and Minkowski superspaces respectively. In particular, we realize their projective embedding via a generalization to the super world of the Segre map and we use it to construct a quantum deformation of the super line bundle realizing this embedding. This strategy allows us to obtain a description of the quantum coordinate superring of the superflag that is then naturally equipped with a coaction of the quantum complex conformal supergroup SLq (4 vertical bar 1). |
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Address |
[Fioresi, R.; Latini, E.] Univ Bologna, Dipartimento Matemat, Piazza Porta S Donato 5, I-40126 Bologna, Italy, Email: rita.fioresi@UniBo.it; |
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Publisher |
Int Press Boston, Inc |
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English |
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ISSN |
1095-0761 |
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Notes |
WOS:000475480800004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4102 |
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Author |
Beltran Jimenez, J.; Delhom, A. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Ghosts in metric-affine higher order curvature gravity |
Type |
Journal Article |
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Year |
2019 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
79 |
Issue ![sorted by Issue field, descending order (down)](img/sort_desc.gif) |
8 |
Pages |
656 - 7pp |
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Abstract |
We disprove the widespread belief that higher order curvature theories of gravity in the metric-affine formalism are generally ghost-free. This is clarified by considering a sub-class of theories constructed only with the Ricci tensor and showing that the non-projectively invariant sector propagates ghost-like degrees of freedom. We also explain how these pathologies can be avoided either by imposing a projective symmetry or additional constraints in the gravity sector. Our results put forward that higher order curvature gravity theories generally remain pathological in the metric-affine (and hybrid) formalisms and highlight the key importance of the projective symmetry and/or additional constraints for their physical viability and, by extension, of general metric-affine theories. |
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Address |
[Beltran Jimenez, Jose] Univ Salamanca, Dept Fis Fundamental, E-37008 Salamanca, Spain, Email: jose.beltran@usal.es; |
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Publisher |
Springer |
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English |
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Series Issue |
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Edition |
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ISSN |
1434-6044 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000479306500020 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
4109 |
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Permanent link to this record |
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Author |
LHCb Collaboration (Aaij, R. et al); Garcia Martin, L.M.; Henry, L.; Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J.; Sanchez Mayordomo, C. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Search for the rare decay B+ -> mu(+) mu(-) mu(+)nu(mu) |
Type |
Journal Article |
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Year |
2019 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
79 |
Issue ![sorted by Issue field, descending order (down)](img/sort_desc.gif) |
8 |
Pages |
675 - 12pp |
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Abstract |
A search for the rare leptonic decay B +. μ+ μ- μ+.mu is performed using proton- proton collision data corresponding to an integrated luminosity of 4.7 fb – 1 collected by the LHCb experiment. The search is carried out in the region where the lowest of the two μ+ μ- mass combinations is below 980 MeV/ c2. The data are consistent with the background- only hypothesis and an upper limit of 1.6x10 – 8 at 95% confidence level is set on the branching fraction in the stated kinematic region. |
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Address |
[Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; dos Reis, A. C.; Gomes, A.; Massafferri, A.; Soares Lavra, L.; Tourinho Jadallah Aoude, R.] CBPF, Rio De Janeiro, Brazil, Email: slavomira.stefkova@desy.de |
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Publisher |
Springer |
Place of Publication |
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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 |
1434-6044 |
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:000480778100002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4110 |
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Permanent link to this record |
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Author |
Stadler, J.; Boehm, C.; Mena, O. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Comprehensive study of neutrino-dark matter mixed damping |
Type |
Journal Article |
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Year |
2019 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
08 |
Issue ![sorted by Issue field, descending order (down)](img/sort_desc.gif) |
8 |
Pages |
014 - 23pp |
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Keywords |
CMBR theory; cosmological perturbation theory; neutrino properties; power spectrum |
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Abstract |
Mixed damping is a physical effect that occurs when a heavy species is coupled to a relativistic fluid which is itself free streaming. As a cross-case between collisional damping and free-streaming, it is crucial in the context of neutrino-dark matter interactions. In this work, we establish the parameter space relevant for mixed damping, and we derive an analytical approximation for the evolution of dark matter perturbations in the mixed damping regime to illustrate the physical processes responsible for the suppression of cosmological perturbations. Although extended Boltzmann codes implementing neutrino-dark matter scattering terms automatically include mixed damping, this effect has not been systematically studied. In order to obtain reliable numerical results, it is mandatory to reconsider several aspects of neutrino-dark matter interactions, such as the initial conditions, the ultra-relativistic fluid approximation and high order multiple moments in the neutrino distribution. Such a precise treatment ensures the correct assessment of the relevance of mixed damping in neutrino-dark matter interactions. |
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Address |
[Stadler, Julia] Univ Durham, Inst Particle Phys Phenomenol, South Rd, Durham DH1 3LE, England, Email: julia.j.stadler@durham.ac.uk; |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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 |
1475-7516 |
ISBN |
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Expedition |
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Conference |
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Notes |
WOS:000481534700003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4111 |
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Permanent link to this record |