23 research outputs found
Parameter space of baryogenesis in the MSM
The Standard Model accompanied with two right-handed neutrinos with the
masses below the weak scale can explain the observed baryon asymmetry of the
Universe. Moreover, this model is at least partially testable in the
forthcoming experiments such as NA62, SHiP, and MATHUSLA. The remarkable
progress in understanding of various rates entering the kinetic equations
describing the asymmetry generation along with considerable improvements of the
numerical procedures allow us to perform a comprehensive analysis of the
parameter space of the model. We find that the region of parameters leading to
the successful baryogenesis is notably larger than it was previously obtained.
Our results are presented in a way that they can be readily used for studies of
sensitivity of various experiments searching for the right-handed neutrinos
responsible for the baryon asymmetry of the Universe. We also present a
detailed comparison with the studies by other groups.Comment: 42 pages, 14 figures, 5 tables, additional data files could be found
at https://doi.org/10.5281/zenodo.1407071; published versio
Testing MSM with indirect searches
We consider neutrino Minimal extension of the Standard Model (MSM),
which by introducing only three sterile neutrinos in sub electroweak region can
explain active neutrino oscillations (via seesaw type I mechanism), baryon
asymmetry of the Universe (leptogenesis via oscillations) and dark matter
phenomena (with keV-scale sterile neutrino forming dark matter). We estimate
sterile neutrino virtual contributions to various lepton flavor and lepton
number violating processes. The contributions are too small, giving no chance
for indirect searches to compete with direct measurements in exploring
MSM.Comment: 13 pages, 4 figures; replaced with the journal versio
To Positivity and Beyond, where Higgs-Dilaton Inflation has never gone before
We study the consequences of (beyond) positivity of scattering amplitudes in
the effective field theory description of the Higgs-Dilaton inflationary model.
By requiring the EFT to be compatible with a unitary, causal, local and Lorentz
invariant UV completion, we derive constraints on the Wilson coefficients of
the first higher order derivative operators. We show that the values allowed by
the constraints are consistent with the phenomenological applications of the
Higgs-Dilaton model.Comment: 27 pages, 6 figures; matches the published versio
Baby Llama: knowledge distillation from an ensemble of teachers trained on a small dataset with no performance penalty
We present our proposed solution to the BabyLM challenge [arXiv:2301.11796],
whose goal was to improve the sample efficiency of language models. We trained
an ensemble consisting of a GPT-2 and small LLaMA models on the
developmentally-plausible, 10M-word BabyLM dataset, then distilled it into a
small, 58M-parameter LLaMA model, which exceeds in performance both of its
teachers as well as a similar model trained without distillation. This suggests
that distillation can not only retain the full performance of the teacher model
when the latter is trained on a sufficiently small dataset; it can exceed it,
and lead to significantly better performance than direct training.Comment: 11 pages, 4 figures, 4 tables, submitted to the BabyLM Challenge
(CoNLL--CMCL 2023 Shared Task
Critical Points in Palatini Higgs Inflation with Small Non-Minimal Coupling
We investigate inflation driven by the Higgs boson in the Palatini
formulation of General Relativity. Our analysis primarily focuses on a small
non-minimal coupling of the Higgs field to gravity in the range . We incorporate the renormalization group running of the relevant parameters
as computed within the Standard Model and allow for small corrections. In
addition to , our model features two tunable parameters: the low-energy
value of the top Yukawa coupling and an effective jump of the Higgs
self-interaction. Our results indicate that critical points leading to a large
enhancement of the power spectrum can be produced. However, the observed
amplitude of perturbations in the CMB cannot be matched within this setting. On
the one hand, this makes it difficult to generate a sizable abundance of
primordial black holes. On the other hand, our finding can be viewed as further
evidence that Palatini Higgs inflation has favourable high-energy properties
due to robustness against quantum corrections.Comment: 42 pages, 11 figures, 1 appendi
Einstein-Cartan gravity, matter, and scale-invariant generalization
We study gravity coupled to scalar and fermion fields in the Einstein-Cartan
framework. We discuss the most general form of the action that contains terms
of mass dimension not bigger than four, leaving out only contributions
quadratic in curvature. By resolving the theory explicitly for torsion, we
arrive at an equivalent metric theory containing additional six-dimensional
operators. This lays the groundwork for cosmological studies of the theory. We
also perform the same analysis for a no-scale scenario in which the Planck mass
is eliminated at the cost of adding an extra scalar degree of freedom. Finally,
we outline phenomenological implications of the resulting theories, in
particular to inflation and dark matter production.Comment: 18 page
Preheating in Palatini Higgs inflation on the lattice
We study preheating following Higgs inflation in the Palatini formulation of
gravity. We numerically evolve perturbations of the radial mode of the Higgs
field and that of three scalars modeling the gauge bosons. We compare the two
non-perturbative mechanisms of growth of excitations -- parametric resonance
and tachyonic instability -- and confirm that the latter plays the dominant
role. Our results provide further evidence that preheating in Palatini Higgs
inflation happens within a single oscillation of the Higgs field about the
bottom of its potential, consistent with the approximation of an instantaneous
preheating.Comment: 20 pages, 9 figures. V2: corrected an error in the Einstein frame
potential of the gauge bosons (eq. 2.18), and added references. V3: appendix
added, matches the published versio