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result(s) for
"Big Bang theory"
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A CMB search for the neutrino mass mechanism and its relation to the Hubble tension
The majoron, a pseudo-Goldstone boson arising from the spontaneous breaking of global lepton number, is a generic feature of many models intended to explain the origin of the small neutrino masses. In this work, we investigate potential imprints in the cosmic microwave background (CMB) arising from massive majorons, should they thermalize with neutrinos after Big Bang Nucleosynthesis via inverse neutrino decays. We show that Planck2018 measurements of the CMB are currently sensitive to neutrino-majoron couplings as small as
λ
∼
10
-
13
, which if interpreted in the context of the type-I seesaw mechanism correspond to a lepton number symmetry breaking scale
v
L
∼
O
(
100
)
GeV
. Additionally, we identify parameter space for which the majoron-neutrino interactions, collectively with an extra contribution to the effective number of relativistic species
N
eff
, can ameliorate the outstanding
H
0
tension.
Journal Article
Big bang! : the tongue-tickling tale of a speck that became spectacular
Discusses the big-bang theory of how a tiny speck became the universe we know today.
Book
Probing the pre-BBN universe with gravitational waves from cosmic strings
A
bstract
Many motivated extensions of the Standard Model predict the existence of cosmic strings. Gravitational waves originating from the dynamics of the resulting cosmic string network have the ability to probe many otherwise inaccessible properties of the early universe. In this study we show how the spectrum of gravitational waves from a cosmic string network can be used to test the equation of state of the early universe prior to Big Bang Nucleosynthesis (BBN). We also demonstrate that current and planned gravitational wave detectors such as LIGO, LISA, DECIGO/BBO, and ET/CE have the potential to detect signals of a non-standard pre-BBN equation of state and evolution of the early universe (e.g., early non-standard matter domination or kination domination) or new degrees of freedom active in the early universe beyond the sensitivity of terrestrial collider experiments and cosmic microwave background measurements.
Journal Article
Joan of Arc in the English Imagination, 1429–1829
In this book, Gail Orgelfinger examines the ways in which English historians and illustrators depicted Joan of Arc over a period of four hundred years, from her capture in 1429 to the early nineteenth century.
The variety of epithets attached to Joan of Arc—from “witch” and “Medean virago” to “missioned Maid” and “shepherd’s child”—attests to England’s complicated relationship with the saint. While portrayals of Joan in English popular culture evolved over the centuries, they do not follow a straightforward trajectory from vituperation to adulation. Focusing primarily on descriptions of Joan’s captivity, trial, and execution, this study shows how the exigencies of politics and the demands of genre shaped English retellings of her military successes, gender transgressions, and execution at the hands of her English enemies. Orgelfinger’s research illuminates how and why English writers and artists used the memory of Joan of Arc to grapple with issues such as England’s relationship with France, emerging protofeminism in the early modern era, and the sense of national guilt over her execution.
A systematic analysis of Joan’s English historiography in its political and social contexts, this volume sheds light on four centuries of English thought on Joan of Arc. It will be welcomed by specialist and general readers alike, especially those interested in women’s studies.
eBook
Cosmology and the evolution of the universe
Covers the current scientific understanding of the creation and evolution of the universe.
Book
Nonrelativistic string theory and T-duality
A
bstract
Nonrelativistic string theory in flat spacetime is described by a two-dimensional quantum field theory with a nonrelativistic global symmetry acting on the worldsheet fields. Nonrelativistic string theory is unitary, ultraviolet complete and has a string spectrum and spacetime S-matrix enjoying nonrelativistic symmetry. The worldsheet theory of nonrelativistic string theory is coupled to a curved spacetime background and to a Kalb-Ramond two-form and dilaton field. The appropriate spacetime geometry for nonrelativistic string theory is dubbed string Newton-Cartan geometry, which is distinct from Riemannian geometry. This defines the sigma model of nonrelativistic string theory describing strings propagating and interacting in curved background fields. We also implement T-duality transformations in the path integral of this sigma model and uncover the spacetime interpretation of T-duality. We show that T-duality along the longitudinal direction of the string Newton-Cartan geometry describes relativistic string theory on a Lorentzian geometry with a compact lightlike isometry, which is otherwise only defined by a subtle infinite boost limit. This relation provides a first principles definition of string theory in the discrete light cone quantization (DLCQ) in an arbitrary background, a quantization that appears in nonperturbative approaches to quantum field theory and string/M-theory, such as in Matrix theory. T-duality along a transverse direction of the string Newton-Cartan geometry equates nonrelativistic string theory in two distinct, T-dual backgrounds.
Journal Article
The amazing unity of the universe : and its origin in the big bang
In the first chapters the author describes how our knowledge of the position of Earth in space and time has developed, thanks to the work of many generations of astronomers and physicists. He discusses how our position in the Galaxy was discovered, and how in 1929, Hubble uncovered the fact that the Universe is expanding, leading to the picture of the Big Bang. He then explains how astronomers have found that the laws of physics that were discovered here on Earth and in the Solar System (the laws of mechanics, gravity, atomic physics, electromagnetism, etc.) are valid throughout the Universe. This is illustrated by the fact that all matter in the Universe consists of atoms of the same chemical elements that we know on Earth. This unity is all the more surprising when one realizes that in the original Big Bang theory, different parts of the Universe could never have communicated with each other.
Book
The onset of star formation 250 million years after the Big Bang
A fundamental quest of modern astronomy is to locate the earliest galaxies and study how they influenced the intergalactic medium a few hundred million years after the Big Bang
1
–
3
. The abundance of star-forming galaxies is known to decline
4
,
5
from redshifts of about 6 to 10, but a key question is the extent of star formation at even earlier times, corresponding to the period when the first galaxies might have emerged. Here we report spectroscopic observations of MACS1149-JD1
6
, a gravitationally lensed galaxy observed when the Universe was less than four per cent of its present age. We detect an emission line of doubly ionized oxygen at a redshift of 9.1096 ± 0.0006, with an uncertainty of one standard deviation. This precisely determined redshift indicates that the red rest-frame optical colour arises from a dominant stellar component that formed about 250 million years after the Big Bang, corresponding to a redshift of about 15. Our results indicate that it may be possible to detect such early episodes of star formation in similar galaxies with future telescopes.
Observation of the emission line of doubly ionized oxygen at a redshift of 9.1096 reveals that star formation began at a redshift of about 15, around 250 million years after the Big Bang.
Journal Article