69 research outputs found
Baryogenesis from Symmetry Principle
In this work, a formalism based on symmetry which allows one to express
asymmetries of all the particles in terms of conserved charges is developed.
The manifestation of symmetry allows one to easily determine the viability of a
baryogenesis scenario and also to identity the different roles played by the
symmetry. This formalism is then applied to the standard model and its
supersymmetric extension, which constitute two important foundations for
constructing models of baryogenesis.Comment: 15 pages, 1 figure, 3 tables. Slight modifications to match the
published versio
The EDGES signal: An imprint from the mirror world?
Recent results from the Experiment to Detect the Global Epoch of Reionization
Signature (EDGES) show an anomalous spectral feature at redshifts
in its 21-cm absorption signal. This deviation from cosmological predictions
can be understood as a consequence of physics that either lower the hydrogen
spin temperature or increases the radiation temperature through the injection
of soft photons in the bath. In the latter case, standard model neutrino decays
induced by effective magnetic and electric transition
moments () are precluded by the tight astrophysical constraints
on . We show that if mirror neutrinos are present in the bath
at early times, an analogous mechanism in the mirror sector can lead to a
population of mirror photons that are then "processed" into visible photons
through resonant conversion, thus accounting for the EDGES signal. We point out
that the mechanism can work for mirror neutrinos which are either heavier than
or degenerate with the standard model (SM) neutrinos, a scenario naturally
realized in mirror twin Higgs models.Comment: 8 pages, 2 figure
Analytic Neutrino Oscillation Probabilities
In the work, we derive exact analytic expressions for -flavor neutrino
oscillation probabilities in an arbitrary matter potential in term of matrix
elements and eigenvalues of the Hamiltonian. With radical solutions for a
quartic polynomial, we obtain the first exact analytic oscillation
probabilities for the -flavor scenario in an arbitrary matter potential.
With the analytic expressions, we demonstrate that nonunitary and nonstandard
neutrino interaction scenarios are physically distinct: they satisfy different
identities and can in principle be distinguished experimentally. The analytic
expressions are implemented in a public code NuProbe, a tool for probing new
physics through neutrino oscillations.Comment: Many new references added, especially on (3+1) analytic solutions
(ours are clearly not the first). NuProbe code available at
https://github.com/shengfong/nuprob
Sphaleron portal baryogenesis
Nontrivial topological vacua of non-Abelian gauge symmetry of the Standard Model play an important role in baryogenesis. In
particular, the baryon (and lepton) number violation from sphaleron
is a crucial ingredient for baryogenesis at weak scale or higher. In this work,
we point out that generically, a baryon asymmetry is induced by an asymmetry
generated in the new sector through strong and/or weak
sphaleron portals and vice versa. In the standard radiation-dominated early
Universe, due to phenomenological constraints, the sphaleron portal
baryogenesis has to take place at cosmic temperature
GeV together with a -violating source. As an example, we show an
explicit model where strong sphaleron portal baryogenesis occurs at the scale
of Peccei-Quinn breaking to solve the strong CP problem and this coincides
nicely with the scale where the Weinberg operator responsible for Majorana
neutrino mass is in equilibrium.Comment: 20 pages (~11 main text), 1 figure. Feedback is welcome
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