543 research outputs found
Gauge Symmetry Breaking through the Hosotani Mechanism in Softly Broken Supersymmetric QCD
Gauge symmetry breaking through the Hosotani mechanism (the dynamics of
nonintegrable phases) in softly broken supersymmetric QCD with
flavors is studied. For even, there is a single SU(N) symmetric vacuum
state, while for odd, there is a doubly degenerate SU(N) symmetric vacuum
state in the model. We also study generalized supersymmetric QCD by adding
numbers of massless adjoint matter. The gauge symmetry breaking
pattern such as is possible for appropriate choices
of the matter content and values of the supersymmetry breaking parameter. The
massless state of the adjoint Higgs scalar is also discussed in the models.Comment: 19 pages, no figure, final version to appear in Phys. Rev.
Dynamics of Nonintegrable Phases in Softly Broken Supersymmetric Gauge Theory with Massless Adjoint Matter
We study SU(N) supersymmetric Yang-Mills theory with massless adjoint matter
defined on . The SU(N) gauge symmetry is broken maximally to
, independent of the number of flavor and the boundary conditions
of the fields associated with the Scherk-Schwarz mechanism of supersymmetry
breaking. The mass of the Higgs scalar is generated through quantum corrections
in the extra dimensions. The quantum correction can become manifest by a finite
Higgs boson mass at low energies even in the limit of small extra dimensions
thanks to the supersymmetry breaking parameter of the Scherk-Schwarz mechanism.Comment: 19 pages, 2 figures, corrected some typo
TeV scale mirage mediation in NMSSM
We study the next-to-minimal supersymmetric standard model. We consider soft
supersymmetry breaking parameters, which are induced by the mirage mediation
mechanism of supersymmetry breaking. We concentrate on the mirage mediation,
where the so-called mirage scale is the TeV scale. In this scenario, we can
realize the up-type Higgs soft mass of O(200) GeV, while other masses such as
gaugino masses and stop masses are heavy such as 1 TeV or more. Cancellation
between the effective \mu-term and the down-type Higgs soft mass ameliorates
the fine-tuning in the electroweak symmetry breaking even for \mu=O(500) GeV.
The mixing between the doublet and singlet Higgs bosons is suppressed by
(\lambda/\kappa)/tan\beta. Then the lightest doublet Higgs mass naturally
reaches 125 GeV lifted by the new quartic coupling. The higgsino and singlino
are light and their linear combination is the lightest superparticle.Comment: 24 pages, 24 figures, Numerical analysis is replaced with the version
calculated by NMSSMTools. Comments and references are added on the suppressed
doublet-singlet mixing and cases in which the 125 GeV boson is the 2nd
lightest CP-even scalar. The version accepted by JHE
How Many Supersymmetries?
Supersymmetry in the gauge sector could be realized as N=1 or N=2
Supersymmetry, but the current LHC searches assume an N=1 realization. In this
paper we show that squarks could be as light as few hundreds of GeV for N=2. We
also describe an experimental procedure to count the number of supersymmetries,
i.e. to distinguish between N=1 and N=2 supersymmetry, based on counting bins
with different jet multiplicities and number of leptons.Comment: 7 pages, 3 figure
Renormalization of the Fayet-Iliopoulos Term in Softly Broken SUSY Gauge Theories
It is shown that renormalization of the Fayet-Iliopoulos term in a softly
broken SUSY gauge theory, in full analogy with all the other soft terms
renormalizations, is completely defined in a rigid or an unbroken theory.
However, contrary to the other soft renormalizations, there is no simple
differential operator that acts on the renormalization functions of a rigid
theory and allows one to get the renormalization of the F-I term. One needs an
analysis of the superfield diagrams and some additional diagram calculations in
components. The method is illustrated by the four loop calculation of some part
of renormalization proportional to the soft scalar masses and the soft triple
couplings.Comment: Latex2e, 14 pages, uses axodraw.sty. References adde
Neutrino masses in R-parity violating supersymmetric models
We study neutrino masses and mixing in R-parity violating supersymmetric
models with generic soft supersymmetry breaking terms. Neutrinos acquire masses
from various sources: Tree level neutrino--neutralino mixing and loop effects
proportional to bilinear and/or trilinear R-parity violating parameters. Each
of these contributions is controlled by different parameters and have different
suppression or enhancement factors which we identified. Within an Abelian
horizontal symmetry framework these factors are related and specific
predictions can be made. We found that the main contributions to the neutrino
masses are from the tree level and the bilinear loops and that the observed
neutrino data can be accommodated once mild fine-tuning is allowed.Comment: 18 pages; minor typos corrected. To be published in Physical Review
Influence of substrate additives on the mechanical properties of ultrathin oxide coatings on poly(ethylene terephthalate)
The mechanical properties of ultrathin silicon oxide (SiOx ) coatings plasma-deposited on poly(ethylene terephthalate) (PET) films were investigated with particular attention paid to the effect of additives located in the superficial layers of the polymer substrate. The cohesive and adhesive properties of the thin oxide coating were derived from the analysis of fragmentation tests carried out in situ in a scanning electron microscope. The cohesive strength of the coating was determined assuming a Weibull probability of failure of the oxide, and the coating/substrate interfacial shear strength (IFSS) was calculated by means of a stress transfer analysis with a perfectly plastic interface. It was shown that the presence of additives in the superficial layers of PET substrates leads to a 20% decrease of the crack onset strain, which is due to an increase of the coating defect density, as revealed by means of atomic oxygen etching. The stress concentration induced by coating microdefects was modeled, and was shown to induce a decrease in the cohesive properties of the coating, which correlates with the observed decrease of crack onset strain. Moreover, the adhesion was found to be very high, with a IFSS higher than the substrate bulk shear stress at yield, irrespective of the presence of additives
Goldstones in Diphotons
We study the conditions for a new scalar resonance to be observed first in
diphotons at the LHC Run-2. We focus on scenarios where the scalar arises
either from an internal or spacetime symmetry broken spontaneously, for which
the mass is naturally below the cutoff and the low-energy interactions are
fixed by the couplings to the broken currents, UV anomalies, and selection
rules. We discuss the recent excess in diphoton resonance searches observed by
ATLAS and CMS at 750 GeV, and explore its compatibility with other searches at
Run-1 and its interpretation as Goldstone bosons in supersymmetry and composite
Higgs models. We show that two candidates naturally emerge: a Goldstone boson
from an internal symmetry with electromagnetic anomalies, and the scalar
partner of the Goldstone of supersymmetry breaking: the sgoldstino. The dilaton
from conformal symmetry breaking is instead disfavoured by present data, in its
minimal natural realization.Comment: 18 pages + refs, 2 figures. v2: typos corrected, references added,
discussions extended and three new plots. Conclusion unchanged. v3: published
versio
18S rRNA processing requires base pairings of snR30 H/ACA snoRNA to eukaryote-specific 18S sequences
The H/ACA RNAs represent an abundant, evolutionarily conserved and functionally diverse class of non-coding RNAs. Many H/ACA RNAs direct pseudouridylation of rRNAs and snRNAs, while members of the rapidly growing group of âorphan' H/ACA RNAs participate in pre-rRNA processing, telomere synthesis and probably, in other nuclear processes. The yeast snR30 âorphan' H/ACA snoRNA has long been known to function in the nucleolytic processing of 18S rRNA, but its molecular role remained unknown. Here, we provide biochemical and genetic evidence demonstrating that during pre-rRNA processing, two evolutionarily conserved sequence elements in the 3âČ-hairpin of snR30 base-pair with short pre-rRNA sequences located in the eukaryote-specific internal region of 18S rRNA. The newly discovered snR30-18S base-pairing interactions are essential for 18S rRNA production and they constitute a complex snoRNA target RNA transient structure that is novel to H/ACA RNAs. We also demonstrate that besides the 18S recognition motifs, the distal part of the 3âČ-hairpin of snR30 contains an additional snoRNA element that is essential for 18S rRNA processing and that functions most likely as a snoRNP protein-binding site
Higgs decay with monophoton + MET signature from low scale supersymmetry breaking
We study the decay of a standard model-like Higgs boson into a gravitino and
a neutralino, which subsequently decays promptly into another gravitino and a
photon. Such a decay can be important in scenarios where the supersymmetry
breaking scale is of the order of a few TeV, and in the region of low
transverse momenta of the photon, it may provide the dominant contribution to
the final state with a photon and two gravitinos. We estimate the relevant
standard model backgrounds and the prospects for discovering this Higgs decay
through a photon and missing transverse energy signal at the LHC in terms of a
simplified model. We also give an explicit model with manifest, but
spontaneously broken, supersymmetry in which the usual MSSM soft terms are
promoted to supersymmetric operators involving a dynamical goldstino
supermultiplet. This model can give rise to a SM-like CP-even neutral Higgs
particle with a mass of 125 GeV, without requiring substantial radiative
corrections, and with couplings sufficiently large for a signal discovery
through the above mentioned Higgs decay channel with the upcoming data from the
LHC.Comment: 28 pages, 5 figures, 4 tables; v2: updated to JHEP version,
references adde
- âŠ