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Journal ArticleDOI

FIMP Dark Matter from Leptogenesis in Fast Expanding Universe

01 Jun 2021-Journal of Cosmology and Astroparticle Physics (IOP Publishing)-Vol. 2021, Iss: 06, pp 006
TL;DR: In this article, a Feebly interacting massive particle (FIMP) was proposed as a dark matter candidate and its effects on the final baryon asymmetry and dark matter abundance were investigated.
Abstract: Within the framework of canonical type-I seesaw, a feebly interacting massive particle (FIMP) $\chi$ is introduced as a dark matter candidate. The leptogenesis mechanism and dark matter relic density share a common origin via decays of Majorana neutrinos $N$. Provided an additional species $\varphi$ whose energy density red-shifts as $\rho_{\varphi}\propto a^{-(4+n)}$, the Hubble expansion rate is larger than the standard scenario, i.e., the Universe expands faster. The consequences of such a fast expanding Universe on leptogenesis as well as FIMP dark matter are investigated in detail. We demonstrate a significant impact on the final baryon asymmetry and dark matter abundance due to the existence of $\varphi$ for the strong washout scenario. While for the weak washout scenario, the effects of FEU are relatively small. We introduce scale factors $F_L$ and $F_\chi$ to describe the corresponding effects of FEU. A semi-analytical approach to derive the efficiency factors $\eta_L$ and $\eta_\chi$ in FEU is also discussed. The viable parameter space for success thermal leptogenesis and correct FIMP DM relic density is obtained for standard cosmology and FEU. Our results show that it is possible to distinguish different cosmology scenarios for strong washout cases.
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors studied the possibility of low scale leptogenesis along with dark matter (DM) in the presence of primordial black holes (PBH) and showed that PBH can lead to non-thermal source of leptonogenesis as well as dilution of thermally generated lepton asymmetry via entropy injection.
Abstract: We study the possibility of low scale leptogenesis along with dark matter (DM) in the presence of primordial black holes (PBH). For a common setup to study both leptogenesis and DM we consider the minimal scotogenic model which also explains light neutrino mass at radiative level. While PBH in the mass range of $0.1-10^5$ g can, in principle, affect leptogenesis, the required initial PBH fraction usually leads to overproduction of DM whose thermal freeze-out occurs before PBH evaporation. PBH can lead to non-thermal source of leptogenesis as well as dilution of thermally generated lepton asymmetry via entropy injection, with the latter being dominant. The parameter space of scotogenic model which leads to overproduction of baryon or lepton asymmetry in standard cosmology can be made consistent in the presence of PBH with appropriate initial mass and energy fraction. On the other hand, for such PBH parameters, the DM is constrained to be in light mass regime where its freeze-out occurs after PBH evaporation.

26 citations

Journal ArticleDOI
TL;DR: In this article , the authors derived analytical expressions for the efficiency factor (which is nothing but solution of set of Boltzmann equations) using certain legible approximations and compared the analytical results with that obtained through numerical solution of Boltzman equations.
Abstract: The expansion rate of the Universe deviates from its standard value when the total energy density includes contribution from a new scalar field apart from the radiation energy density. The non-trivial modifications incurred in the Boltzmann equations render the well known analytical solutions unsuitable in non standard scenario. In the present study we derive analytical expressions for the efficiency factor (which is nothing but solution of set of Boltzmann equations) using certain legible approximations. A fair degree of accuracy of these formulas have been observed by juxtaposing the analytical results with that obtained through numerical solution of Boltzmann equations. Faster expansion of the Universe results in decrement of the effective decay parameter which brings down the amount of washout of asymmetry due to inverse decay. Thus in non-standard cosmology scenario, a larger fraction of the asymmetry (generated at early epoch) is expected to survive till present epoch. Alteration of the cosmology does not affect the underlying particle physics model responsible for the generation of the CP asymmetry. Therefore starting from an identical particle physics model we will end up with a larger final baryon asymmetry in the non-standard scenario. It hints towards the possible relaxation of the lower bound of the lightest right handed neutrino mass required to produce adequate asymmetry which is in agreement with current experimental data.

5 citations

Journal ArticleDOI
TL;DR: In this article , the authors considered the possibility of generating baryon asymmetry of the universe from dark matter (DM) annihilations during non-standard cosmological epochs.
Abstract: We study the possibility of generating baryon asymmetry of the universe from dark matter (DM) annihilations during non-standard cosmological epochs. Considering the DM to be of weakly interacting massive particle (WIMP) type, the generation of baryon asymmetry via leptogenesis route is studied where WIMP DM annihilation produces a non-zero lepton asymmetry. Adopting a minimal particle physics model to realise this along with non-zero light neutrino masses, we consider three different types of non-standard cosmic history namely, (i) fast expanding universe, (ii) early matter domination and (iii) scalar-tensor theory of gravity. By solving the appropriate Boltzmann equations incorporating such non-standard history, we find that the allowed parameter space consistent with DM relic and observed baryon asymmetry gets enlarged with the possibility of lower DM mass in some scenarios. While such lighter DM can face further scrutiny at direct search experiments, the non-standard epochs offer complementary probes on their own.

5 citations

Posted Content
TL;DR: In this paper, the authors study the simultaneous evolution of baryon asymmetry and hypermagnetic field amplitude assuming an early matter domination and find that a change in the Hubble rate can have a significant impact on when the weak sphalerons become active.
Abstract: In this paper, we study the simultaneous evolution of baryon asymmetry and hypermagnetic field amplitude assuming an early matter domination. We contrast our results to the conventional case where radiation domination during early universe is assumed. We show that the baryon asymmetry and the hypermagntic field amplitude can change by orders of magnitude if we assume a non-standard history of cosmology. That is because the Hubble rate determines which processes are efficient. We find that a change in Hubble rate can have a significant impact on when the weak sphalerons become active. As a result of a change in the evolution of baryonic asymmetry, alters the evolution of hypermagnetic field amplitude. It is known that if the hypermagnetic field amplitude is large enough, it can save the baryon asymmetry from diminishing. We show that whether a small seed of hypermagnetic field amplitude can be amplified to a large enough value will strongly depend on the history of cosmology.

1 citations

Peer Review
24 Mar 2023
TL;DR: In this article , it has been observed through numerical estimations that the minimum mass of the decaying triplet, required to produce sufficient baryon asymmetry, can be lowered up to two orders (compared to the standard cosmology) in this fast expansion scenario.
Abstract: The indirect searches of Dark Matter (DM), in conjugation with the so called `missing track searches' at the collider seems to confine fermion triplet DM mass within a narrow range around 1 TeV. The canonical picture of pure triplet fermionic DM is in tension since it is under-abundant for the said mass range. Several preceding studies have shown that the existence of an extra species over the radiation background, prior to the Big Bang Nucleosynthesis, leads to a fast expanding Universe driven by an enhanced Hubble parameter. This faster (than radiation) expansion has the potential to revive the under-abundant fermion triplet ($\mathbb{Z}_2$ odd) WIMP dark matter scenario by causing freeze-out earlier without modifying the interaction strength between DM and thermal bath. Although the CP asymmetry, produced due to the decay of $\mathbb{Z}_2$ even heavier generations of the triplet, remains unaffected by the modification of cosmology, the evolution of the same receives significant non-trivial effect. It has been observed through numerical estimations that the minimum mass of the decaying triplet, required to produce sufficient baryon asymmetry, can be lowered up to two orders (compared to the standard cosmology) in this fast expansion scenario. The non-standard parameters $n$ and $T_r$, which simultaneously control the DM relic abundance as well the frozen value of baryon asymmetry, are tightly constrained due to consecutive imposition of experimental bounds on relic density followed by observed value of baryon asymmetry of the Universe. It has been found that $n$ is strictly bounded within the interval $0.4\lesssim n \lesssim 1.6$. The upper bound is imposed by the baryon asymmetry constraint whereas the lower bound arises to satisfy the correct relic abundance of the DM. The restriction on $T_r$ is not so stringent as it can vary from sub GeV to few tens of GeV.

1 citations

References
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Journal ArticleDOI
TL;DR: In weak-interaction models with spontaneous parity nonconservation, this article obtained the following formula for the neutrino mass, valid for each lepton generation, which relates the maximality of observed parity non-conservation at low energies to the smallness of neutrinos masses.
Abstract: In weak-interaction models with spontaneous parity nonconservation, based on the gauge group $\mathrm{SU}{(2)}_{L}\ensuremath{\bigotimes}\mathrm{SU}{(2)}_{R}\ensuremath{\bigotimes}\mathrm{U}(1)$, we obtain the following formula for the neutrino mass: ${m}_{{\ensuremath{ u}}_{e}}\ensuremath{\simeq}\frac{{{m}_{e}}^{2}}{g{m}_{{W}_{R}}}$, where ${W}_{R}$ is the gauge boson which mediates right-handed weak interactions. This formula, valid for each lepton generation, relates the maximality of observed parity nonconservation at low energies to the smallness of neutrino masses.

4,895 citations

Journal ArticleDOI
Nabila Aghanim1, Yashar Akrami2, Yashar Akrami3, Yashar Akrami4  +229 moreInstitutions (70)
TL;DR: In this article, the authors present cosmological parameter results from the full-mission Planck measurements of the cosmic microwave background (CMB) anisotropies, combining information from the temperature and polarization maps and the lensing reconstruction.
Abstract: We present cosmological parameter results from the final full-mission Planck measurements of the cosmic microwave background (CMB) anisotropies, combining information from the temperature and polarization maps and the lensing reconstruction Compared to the 2015 results, improved measurements of large-scale polarization allow the reionization optical depth to be measured with higher precision, leading to significant gains in the precision of other correlated parameters Improved modelling of the small-scale polarization leads to more robust constraints on manyparameters,withresidualmodellinguncertaintiesestimatedtoaffectthemonlyatthe05σlevelWefindgoodconsistencywiththestandard spatially-flat6-parameter ΛCDMcosmologyhavingapower-lawspectrumofadiabaticscalarperturbations(denoted“base ΛCDM”inthispaper), from polarization, temperature, and lensing, separately and in combination A combined analysis gives dark matter density Ωch2 = 0120±0001, baryon density Ωbh2 = 00224±00001, scalar spectral index ns = 0965±0004, and optical depth τ = 0054±0007 (in this abstract we quote 68% confidence regions on measured parameters and 95% on upper limits) The angular acoustic scale is measured to 003% precision, with 100θ∗ = 10411±00003Theseresultsareonlyweaklydependentonthecosmologicalmodelandremainstable,withsomewhatincreasederrors, in many commonly considered extensions Assuming the base-ΛCDM cosmology, the inferred (model-dependent) late-Universe parameters are: HubbleconstantH0 = (674±05)kms−1Mpc−1;matterdensityparameterΩm = 0315±0007;andmatterfluctuationamplitudeσ8 = 0811±0006 We find no compelling evidence for extensions to the base-ΛCDM model Combining with baryon acoustic oscillation (BAO) measurements (and consideringsingle-parameterextensions)weconstraintheeffectiveextrarelativisticdegreesoffreedomtobe Neff = 299±017,inagreementwith the Standard Model prediction Neff = 3046, and find that the neutrino mass is tightly constrained toPmν < 012 eV The CMB spectra continue to prefer higher lensing amplitudesthan predicted in base ΛCDM at over 2σ, which pulls some parameters that affect thelensing amplitude away from the ΛCDM model; however, this is not supported by the lensing reconstruction or (in models that also change the background geometry) BAOdataThejointconstraintwithBAOmeasurementsonspatialcurvatureisconsistentwithaflatuniverse, ΩK = 0001±0002Alsocombining with Type Ia supernovae (SNe), the dark-energy equation of state parameter is measured to be w0 = −103±003, consistent with a cosmological constant We find no evidence for deviations from a purely power-law primordial spectrum, and combining with data from BAO, BICEP2, and Keck Array data, we place a limit on the tensor-to-scalar ratio r0002 < 006 Standard big-bang nucleosynthesis predictions for the helium and deuterium abundances for the base-ΛCDM cosmology are in excellent agreement with observations The Planck base-ΛCDM results are in good agreement with BAO, SNe, and some galaxy lensing observations, but in slight tension with the Dark Energy Survey’s combined-probe results including galaxy clustering (which prefers lower fluctuation amplitudes or matter density parameters), and in significant, 36σ, tension with local measurements of the Hubble constant (which prefer a higher value) Simple model extensions that can partially resolve these tensions are not favoured by the Planck data

4,688 citations

Journal ArticleDOI
TL;DR: The current status of particle dark matter, including experimental evidence and theoretical motivations, including direct and indirect detection techniques, is discussed in this paper. But the authors focus on neutralinos in models of supersymmetry and Kaluza-Klein dark matter in universal extra dimensions.

4,614 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that lepton number conservation, purely left-handed charged weak currents and vanishing neutrino masses are a limiting case of a parity symmetric SU2L × SUR × U2V gauge theory.

4,076 citations

Journal ArticleDOI
Y. Fukuda1, T. Hayakawa1, E. Ichihara1, Kunio Inoue1, K. Ishihara1, H. Ishino1, Yoshitaka Itow1, Takaaki Kajita1, J. Kameda1, S. Kasuga1, Ken-ichiro Kobayashi1, Yohei Kobayashi1, Yusuke Koshio1, M. Miura1, Masayuki Nakahata1, S. Nakayama1, A. Okada1, Ko Okumura1, N. Sakurai1, Masato Shiozawa1, Yoshihiro Suzuki1, Y. Takeuchi1, Y. Totsuka1, Shinya Yamada1, M. Earl2, Alec Habig2, E. Kearns2, M. D. Messier2, Kate Scholberg2, J. L. Stone2, Lawrence Sulak2, C. W. Walter2, M. Goldhaber3, T. Barszczxak4, D. Casper4, W. Gajewski4, P. G. Halverson4, J. Hsu4, W. R. Kropp4, L. R. Price4, Frederick Reines4, Michael B. Smy4, Henry W. Sobel4, Mark R. Vagins4, K. S. Ganezer5, W. E. Keig5, R. W. Ellsworth6, S. Tasaka7, J. W. Flanagan8, A. Kibayashi8, John G. Learned8, S. Matsuno8, V. J. Stenger8, D. Takemori8, T. Ishii, Junichi Kanzaki, T. Kobayashi, S. Mine, K. Nakamura, K. Nishikawa, Yuichi Oyama, A. Sakai, Makoto Sakuda, Osamu Sasaki, S. Echigo9, M. Kohama9, A. T. Suzuki9, Todd Haines4, Todd Haines10, E. Blaufuss11, B. K. Kim11, R. Sanford11, R. Svoboda11, M. L. Chen12, Z. Conner13, Z. Conner12, J. A. Goodman12, G. W. Sullivan12, J. Hill14, C. K. Jung14, K. Martens14, C. Mauger14, C. McGrew14, E. Sharkey14, B. Viren14, C. Yanagisawa14, W. Doki15, Kazumasa Miyano15, H. Okazawa15, C. Saji15, M. Takahata15, Y. Nagashima16, M. Takita16, Takashi Yamaguchi16, Minoru Yoshida16, Soo-Bong Kim17, M. Etoh18, K. Fujita18, Akira Hasegawa18, Takehisa Hasegawa18, S. Hatakeyama18, T. Iwamoto18, M. Koga18, Tomoyuki Maruyama18, Hiroshi Ogawa18, J. Shirai18, A. Suzuki18, F. Tsushima18, Masatoshi Koshiba1, M. Nemoto19, Kyoshi Nishijima19, T. Futagami20, Y. Hayato20, Y. Kanaya20, K. Kaneyuki20, Y. Watanabe20, D. Kielczewska21, D. Kielczewska4, R. A. Doyle22, J. S. George22, A. L. Stachyra22, L. Wai23, L. Wai22, R. J. Wilkes22, K. K. Young22 
Abstract: We present an analysis of atmospheric neutrino data from a 33.0 kton yr (535-day) exposure of the Super-Kamiokande detector. The data exhibit a zenith angle dependent deficit of muon neutrinos which is inconsistent with expectations based on calculations of the atmospheric neutrino flux. Experimental biases and uncertainties in the prediction of neutrino fluxes and cross sections are unable to explain our observation. The data are consistent, however, with two-flavor ${\ensuremath{ u}}_{\ensuremath{\mu}}\ensuremath{\leftrightarrow}{\ensuremath{ u}}_{\ensuremath{\tau}}$ oscillations with ${sin}^{2}2\ensuremath{\theta}g0.82$ and $5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}l\ensuremath{\Delta}{m}^{2}l6\ifmmode\times\else\texttimes\fi{}1{0}^{\ensuremath{-}3}\mathrm{eV}{}^{2}$ at 90% confidence level.

3,784 citations