Article
Astronomy & Astrophysics
Debasish Borah, Arnab Dasgupta
Summary: We study leptogenesis scenarios with decay or scattering as the source of lepton asymmetry, finding that a TeV scale leptogenesis, especially of the 1-N(N≥3) type, can generate the required lepton asymmetry and a large neutrino asymmetry of O(10-2) by the epoch of big bang nucleosynthesis. The large neutrino asymmetry can be probed at future cosmic microwave background experiments and may help explain anomalies in 4He measurements. Additionally, it offers the possibility of cogenesis if dark matter is a sterile neutrino produced via the Shi-Fuller mechanism.
Article
Physics, Particles & Fields
Lavina Sarma, Bichitra Bijay Boruah, Mrinal Kumar Das
Summary: In this study, we investigated the phenomenology of dark matter, neutrinoless double beta decay, and low scale leptogenesis. We proposed an extension of the Standard Model with three neutral fermions, a scalar doublet, and a dark sector consisting of a singlet scalar and a Dirac singlet fermion, to explain the mass patterns of neutrinos and accommodate dark matter mass. We also analyzed the dependence of various phenomena on decay parameters for different choices of arbitrary complex angles.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Physics, Particles & Fields
Devabrat Mahanta, Debasish Borah
Summary: We propose a gauged B-L extension of the standard model where light neutrinos are of Dirac type, achieved through tiny Yukawa couplings. Additional heavy Majorana fermions are included to achieve leptogenesis without introducing B-L violation. The model also considers the constraints from dark matter requirements and thermalized relativistic degrees of freedom from light Dirac neutrinos.
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Torsten Bringmann, Paul Frederik Depta, Marco Hufnagel, Joern Kersten, Joshua T. Ruderman, Kai Schmidt-Hoberg
Summary: We propose a new mechanism for generating undetectable sterile neutrinos vs in the early Universe, through the conversion of ordinary neutrinos va in scattering processes vsva -> vsvs. This leads to an exponential growth in the abundance of vs after initial production by oscillations. We demonstrate that this production regime occurs naturally for self-interacting vs, offering significant opportunities for vs to account for all observed dark matter. Our findings provide strong motivation to enhance the sensitivity of X-ray line searches and improve constraints from structure formation.
Article
Astronomy & Astrophysics
Waqas Ahmed, Athanasios Karozas, George K. Leontaris
Summary: The study revisits Higgs inflation in a minimal extension of the Standard Model, finding that the gravitino may be a potential candidate for dark matter in certain parameter regions. It also shows the effective implementation of the inflationary scenario and nonthermal leptogenesis.
Article
Physics, Particles & Fields
Ang Liu, Feng-Lan Shao, Zhi-Long Han, Yi Jin, Honglei Li
Summary: In this paper, a model of sterile neutrino portal dark matter in vTHDM is proposed. This model can naturally generate tiny neutrino mass with the neutrinophilic scalar doublet (I)v and sterile neutrinos N around TeV scale. a Z2 symmetry, a Dirac fermion singlet x and a scalar singlet 0 are introduced in the dark sector. The sterile neutrinos N act as mediators between the DM and SM. Depending on the coupling strength, the DM can be either WIMP or FIMP. The key channel for the WIMP scenario is the pair annihilation of DM into N N, which can be tested at indirect detection experiments. For the FIMP scenario, besides the direct production of DM from freeze-in mechanism, contributions from late decay of NLOP are also important. When sterile neutrinos are heavier than the dark sector, NLOP is long-lived due to tiny mixing angle between sterile and light neutrinos. Constrains from free streaming length, CMB, BBN and neutrino experiments are considered.
EUROPEAN PHYSICAL JOURNAL C
(2023)
Article
Physics, Nuclear
Nayana Gautam, Mrinal Kumar Das
Summary: The study focuses on the S-4 flavor symmetric inverse seesaw model as a potential solution for addressing neutrino phenomenology, dark matter, and baryon asymmetry through leptogenesis. The model introduces additional neutrinos and sterile fermions to the standard model, leading to a keV scale sterile neutrino dark matter and quasi-Dirac states. The CP violating decay in the model generates lepton asymmetry which then converts to baryon asymmetry, providing a simultaneous solution for these cosmological phenomena.
INTERNATIONAL JOURNAL OF MODERN PHYSICS A
(2021)
Article
Astronomy & Astrophysics
Djuna Croon, Hooman Davoudiasl, Rachel Houtz
Summary: The researchers propose a new idea that weak scale leptogenesis can occur via TeV scale right-handed neutrinos with temporary larger coupling values in the early Universe. They suggest that the lifted parameters required for this can be achieved by the displacement of a light scalar ?? from its origin due to the thermal population of fermions X. The fermion X can be a viable dark matter candidate and the light scalar itself can also be dark matter through a misalignment mechanism. The researchers find that a two-component dark matter population consisting of both X and ?? is a typical outcome in their framework.
Article
Physics, Nuclear
Subhasmita Mishra, Shivaramakrishna Singirala, Suchismita Sahoo
Summary: Research on the phenomenology of singlet scalar dark matter in a simple U(1)( B-L ) gauge extension of the standard model was conducted, with the addition of four exotic fermions for anomaly-free conditions. The study focused on calculating relic density, DM-nucleon cross section, mass of Z ' and gauge coupling, as well as discussing the impact of flavor in leptogenesis. Constraints on new gauge parameters were also examined, revealing more stringent restrictions from the dark sector compared to the flavor sector.
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Srubabati Goswami, K. N. Vishnudath, Ananya Mukherjee, Nimmala Narendra
Summary: In this study, we investigate the minimal extended seesaw model that can accommodate an eV scale sterile neutrino. The model includes nonunitary active-sterile mixing parameters, which deviate the Pontecorvo-Maki-Nakagawa-Sakata matrix from unitarity. Oscillation data from various experiments place an upper bound on the mass scale of the lightest heavy neutrino in this model. We also explore vanilla leptogenesis in this scheme and find that the parameter space for successful leptogenesis is constrained by the bounds on the active-sterile mixing obtained from global analysis.
Article
Astronomy & Astrophysics
C. S. Fong, T. Gregoire, A. Tonero
Summary: The article discusses a novel scenario where new physics causes heavy fermion singlets and SM neutrinos to split into pairs of quasi-Dirac states. Above the weak scale, the cosmic matter-antimatter asymmetry can be generated through resonant leptogenesis from the decay of heavy singlets. Nontrivially, the CP violation for leptogenesis is bounded by the light neutrino mass splitting, which can be probed in neutrino oscillation experiments.
Article
Astronomy & Astrophysics
Debasish Borah, Arnab Dasgupta, Satyabrata Mahapatra, Narendra Sahu
Summary: We propose a framework where a light scalar field can give rise to dark matter self-interactions and enhance CP asymmetry required for successful baryon asymmetry. In a scotogenic seesaw scenario, we demonstrate how the lightest right-handed neutrinos can play the role of dark matter and contribute to both dark matter relic and lepton asymmetry. The model can explain nonzero neutrino mass and be tested through various experiments related to dark matter, flavor physics, and colliders.
Article
Astronomy & Astrophysics
Debasish Borah, Arnab Dasgupta, Devabrat Mahanta
Summary: This study explores the potential of achieving leptogenesis through three body decay, dark matter, and neutrino mass in a minimal framework. A novel model is proposed to implement the idea of leptogenesis from three body decay with interference of multiple diagrams using resummed propagators along with dark matter. By extending the standard model with additional fields, successful leptogenesis can occur at a lower scale, leading to a two component scalar singlet-doublet dark matter scenario.
Article
Astronomy & Astrophysics
Pritam Das, Najimuddin Khan
Summary: We propose a new physics model that extends the Standard Model (SM) by introducing hyperchargeless Y=0 triplet fermions and a Higgs triplet with hypercharge Y=2. This model provides a unified framework for explaining neutrino mass and mixing, dark matter, baryogenesis, inflation, and the reheating temperature of the Universe. The model predicts that the two Z2 even neutral fermions explain neutrino low energy variables, while the third Z2 odd fermion triplet serves as a viable dark matter candidate and the scalar triplet acts as the inflaton. Reheating analysis shows that the triplet fermions associated with the Z2 even sector can explain the observed baryon asymmetry at the TeV scale.
Article
Physics, Particles & Fields
Rabindra N. Mohapatra, Nobuchika Okada
Summary: The Affleck-Dine mechanism plays a crucial role in leptogenesis by involving the evolution of a complex scalar field. This mechanism provides a unified framework for solving four major puzzles of the standard model – inflation, baryogenesis, dark matter, and neutrino mass. Phenomenological implications of this model are also discussed.
JOURNAL OF HIGH ENERGY PHYSICS
(2022)
