| Records |
| Author |
Creminelli, P.; Norena, J.; Pena, M.; Simonovic, M. |
Title  |
Khronon inflation |
Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
11 |
Issue |
11 |
Pages |
032 - 16pp |
| Keywords |
inflation; modified gravity; non-gaussianity |
| Abstract |
We study the possibility that the approximate time shift symmetry during inflation is promoted to the full invariance under time reparametrization t -> (t) over tilde (t), or equivalently under field redefinition of the inflaton phi -> (phi) over tilde(phi). The symmetry allows only two operators at leading order in derivatives, so that all n-point functions of scalar perturbations are fixed in terms of the power spectrum normalization and the speed of sound. During inflation the decaying mode only decays as 1/a and this opens up the possibility to violate some of the consistency relations in the squeezed limit, although this violation is suppressed by the (small) breaking of the field reparametrization symmetry. In particular one can get terms in the 3-point function that are only suppressed by 1/k(L) in the squeezed limit k(L) -> 0 compared to the local shape. |
| Address |
[Creminelli, Paolo] Abdus Salam Int Ctr Theoret Phys, I-34151 Trieste, Italy, Email: creminel@ictp.it; |
| Corporate Author |
|
Thesis |
|
| Publisher |
Iop Publishing Ltd |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1475-7516 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000312263500015 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1274 |
| Permanent link to this record |
| |
|
| |
| Author |
Bombacigno, F.; Moretti, F.; Boudet, S.; Olmo, G.J. |
| Title |
Landau damping for gravitational waves in parity-violating theories |
Type |
Journal Article |
| Year |
2023 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
02 |
Issue |
2 |
Pages |
009 - 29pp |
| Keywords |
Gravitational waves in GR and beyond: theory; modified gravity; gravitational waves / experiments; dark matter experiments |
| Abstract |
We discuss how tensor polarizations of gravitational waves can suffer Landau damping in the presence of velocity birefringence, when parity symmetry is explicitly broken. In particular, we analyze the role of the Nieh-Yan and Chern-Simons terms in modified theories of gravity, showing how the gravitational perturbation in collisionless media can be characterized by a subluminal phase velocity, circumventing the well-known results of General Relativity and allowing for the appearance of the kinematic damping. We investigate in detail the connection between the thermodynamic properties of the medium, such as temperature and mass of the particles interacting with the gravitational wave, and the parameters ruling the parity violating terms of the models. In this respect, we outline how the dispersion relations can give rise in each model to different regions of the wavenumber space, where the phase velocity is subluminal, superluminal or does not exist. Quantitative estimates on the considered models indicate that the phenomenon of Landau damping is not detectable given the sensitivity of present-day instruments. |
| Address |
[Bombacigno, F.; Moretti, F.; Olmo, Gonzalo J.] Ctr Mixto Univ Valencia, CSIC, Dept Fis Teor, Carrer Doctor Moliner 50, Valencia 46100, Spain, Email: flavio2.bombacigno@uv.es; |
| Corporate Author |
|
Thesis |
|
| Publisher |
IOP Publishing Ltd |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1475-7516 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:001040875600002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5624 |
| Permanent link to this record |
| |
|
| |
| Author |
Aristizabal Sierra, D.; Tortola, M.; Valle, J.W.F.; Vicente, A. |
| Title |
Leptogenesis with a dynamical seesaw scale |
Type |
Journal Article |
| Year |
2014 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
052 - 20pp |
| Keywords |
leptogenesis; baryon asymmetry; particle physics – cosmology connection; neutrino theory |
| Abstract |
In the simplest type-I seesaw leptogenesis scenario right-handed neutrino annihilation processes are absent. However, in the presence of new interactions these processes are possible and can affect the resulting B – L asymmetry in an important way. A prominent example is provided by models with spontaneous lepton number violation, where the existence of new dynamical degrees of freedom can play a crucial role. In this context, we provide a model-independent discussion of the effects of right-handed neutrino annihilations. We show that in the weak washout regime, as long as the scattering processes remain slow compared with the Hubble expansion rate throughout the relevant temperature range, the efficiency can be largely enhanced, reaching in some cases maximal values. Moreover, the B – L asymmetry yield turns out to be independent upon initial conditions, in contrast to the “standard” case. On the other hand, when the annihilation processes are fast, the right-handed neutrino distribution tends to a thermal one down to low temperatures, implying a drastic suppression of the efficiency which in some cases can render the B – L generation mechanism inoperative. |
| Address |
[Sierra, D. Aristizabal; Vicente, A.] Univ Liege, IFPA, Dept Astrophys Geophys & Oceanog, B-4000 Liege, Belgium, Email: daristizabal@ulg.ac.be; |
| Corporate Author |
|
Thesis |
|
| Publisher |
Iop Publishing Ltd |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1475-7516 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000339802700053 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1868 |
| Permanent link to this record |
| |
|
| |
| Author |
Racker, J.; Pena, M.; Rius, N. |
| Title |
Leptogenesis with small violation of B – L |
Type |
Journal Article |
| Year |
2012 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
030 - 18pp |
| Keywords |
leptogenesis; neutrino theory |
| Abstract |
We analyze leptogenesis in the context of seesaw models with almost conserved lepton number, focusing on the L-conserving contribution to the flavoured CP asymmetries. We find that, contrary to previous claims, successful leptogenesis is feasible for masses of the lightest heavy neutrino as low as M-1 similar to 10(6) GeV, without resorting to the resonant enhancement of the CP asymmetry for strongly degenerate heavy neutrinos. This lower limit renders thermal leptogenesis compatible with the gravitino bound in supersymmetric scenarios. |
| Address |
[Racker, J.; Pena, Manuel; Rius, Nuria] Univ Valencia, CSIC, Dept Fis Teor, Valencia 46071, Spain, Email: racker@ific.uv.es; |
| Corporate Author |
|
Thesis |
|
| Publisher |
Iop Publishing Ltd |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1475-7516 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000307079600025 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
1166 |
| Permanent link to this record |
| |
|
| |
| Author |
Bhattacharya, S.; Mondal, N.; Roshan, R.; Vatsyayan, D. |
| Title |
Leptogenesis, dark matter and gravitational waves from discrete symmetry breaking |
Type |
Journal Article |
| Year |
2024 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
06 |
Issue |
6 |
Pages |
029 - 25pp |
| Keywords |
leptogenesis; dark matter theory; gravitational waves / theory |
| Abstract |
We analyse a model that connects the neutrino sector and the dark sector of the universe via a mediator 41., stabilised by a discrete Z4 symmetry that breaks to a remnant Z2 upon 41. acquiring a non -zero vacuum expectation value (v phi). The model accounts for the observed baryon asymmetry of the universe via additional contributions to the canonical Type -I leptogenesis. The Z4 symmetry breaking scale (v phi) in the model not only establishes a connection between the neutrino sector and the dark sector, but could also lead to gravitational wave signals that are within the reach of current and future experimental sensitivities. |
| Address |
[Bhattacharya, Subhaditya; Mondal, Niloy] Indian Inst Technol Guwahati, Dept Phys, Gauhati 781039, Assam, India, Email: subhab@iitg.ac.in; |
| Corporate Author |
|
Thesis |
|
| Publisher |
IOP Publishing Ltd |
Place of Publication |
|
Editor |
|
| Language |
English |
Summary Language |
|
Original Title |
|
| Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1475-7516 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:001246744300003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
6162 |
| Permanent link to this record |
