57 research outputs found
The minimal linear sigma model for the Goldstone Higgs
In the context of the minimal SO(5) linear {\sigma}-model, a complete
renormalizable Lagrangian -including gauge bosons and fermions- is considered,
with the symmetry softly broken to SO(4). The scalar sector describes both the
electroweak Higgs doublet and the singlet {\sigma}. Varying the {\sigma} mass
would allow to sweep from the regime of perturbative ultraviolet completion to
the non-linear one assumed in models in which the Higgs particle is a
low-energy remnant of some strong dynamics. We analyze the phenomenological
implications and constraints from precision observables and LHC data.
Furthermore, we derive the d <= 6 effective Lagrangian in the limit of heavy
exotic fermions
Dark matter from an even lighter QCD axion: trapped misalignment
We show that dark matter can be accounted for by an axion that solves the
strong CP problem, but is much lighter than usual due to a
symmetry. The whole mass range from the canonical QCD axion down to the
ultra-light regime is allowed, with . This includes
the first proposal of a "fuzzy dark matter" QCD axion with
eV. A novel misalignment mechanism occurs --{\it trapped misalignment}-- due to
the peculiar temperature dependence of the axion potential.
The dark matter relic density is enhanced because the axion field undergoes two
stages of oscillations: it is first trapped in the wrong minimum, which
effectively delays the onset of true oscillations. Trapped misalignment is more
general than the setup discussed here, and may hold whenever an extra source of
Peccei-Quinn breaking appears at high temperatures. Furthermore, it will be
shown that trapped misalignment can dynamically source the recently proposed
kinetic misalignment mechanism. All the parameter space is within tantalizing
reach of the experimental projects for the next decades. For instance, even
Phase I of CASPEr-Electric could discover this axion.Comment: 48 pages, 21 figure
On discrete Goldstone bosons
Exact discrete symmetries, if non-linearly realized, can reduce the
ultraviolet sensitivity of a given theory. The scalars stemming from
spontaneous symmetry breaking are massive without breaking the discrete
symmetry, and those masses are protected from divergent quadratic corrections.
This is in contrast to non-linearly realized continuous symmetries. The
symmetry-protected masses and potentials of those discrete Goldstone bosons
offer promising physics avenues, both theoretically and in view of the blooming
experimental search for ALPs. In this text, we develop this theoretical setup
for the specific case of a triplet of using invariant theory, showcasing
the substantial improvements and compelling phenomenological consequences
introduced by the invariance under a discrete symmetry.Comment: 6 pages, 2 figures. Contribution to the proceedings of the 8th
Symposium on Prospects in the Physics of Discrete Symmetries (DISCRETE 2022
CP Violation from Dimensional Reduction: Examples in 4+1 Dimensions
We provide simple examples of the generation of complex mass terms and hence
CP violation through dimensional reduction.Comment: 6 pages, typos corrected, 1 reference adde
Phenomenology of symmetry breaking from extra dimensions
Motivated by the electroweak hierarchy problem, we consider theories with two
extra dimensions in which the four-dimensional scalar fields are components of
gauge boson in full space. We explore the Nielsen-Olesen instability for SU(N)
on a torus, in the presence of a magnetic background. A field theory approach
is developed, computing explicitly the minimum of the complete effective
potential, including tri-linear and quartic couplings and determining the
symmetries of the stable vacua. We also develop appropriate gauge-fixing terms
when both Kaluza-Klein and Landau levels are present and interacting,
discussing the interplay between the possible six and four dimensional choices.
The equivalence between coordinate dependent and constant Scherk-Schwarz
boundary conditions -associated to either continuous or discrete Wilson lines-
is analyzed.Comment: 39 pages and 8 eps figures. Few changes in section
Summary report of MINSIS workshop in Madrid
Recent developments on tau detection technologies and the construction of
high intensity neutrino beams open the possibility of a high precision search
for non-standard {\mu} - {\tau} flavour transition with neutrinos at short
distances. The MINSIS - Main Injector Non-Standard Interaction Search- is a
proposal under discussion to realize such precision measurement. This document
contains the proceedings of the workshop which took place on 10-11 December
2009 in Madrid to discuss both the physics reach as well as the experimental
requirements for this proposal.Comment: Proceedings of the MINSIS Workshop, Dec 10-11, 2009 in Madrid. 15
pages late
CP violation in the Standard Model
A basis introduction to CP violation will be developed,with emphasis on the three generation Standard Model predictions. Implications for Kaon physics, electric dipole moments and B physics will be discussed in detail.A basis introduction to CP violatio
Supersymmetric contributions to the epsilon-prime and cp violating parameters
info:eu-repo/semantics/publishe
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