1,427 research outputs found
Bulk gauge and matter fields in nested warping: I. the formalism
The lack of evidence for a TeV-mass graviton has been construed as
constricting the Randall-Sundrum model. However, a doubly-warped generalization
naturally avoids such restrictions. We develop, here, the formalism for
extension of the Standard Model gauge bosons and fermions into such a
six-dimensional bulk. Apart from ameliorating the usual problems such as
flavour-changing neutral currents, this model admits two very distinct phases,
with their own unique phenomenologies.Comment: 44 pages, 5 figures, version to appear in JHEP. Corrected minor
typographical error
The Effect Of Four Endodontic Irrigants on the Shear Bond Strength of a Self Etch Resin Based Sealer to Dentin: An Invitro Study
The present in vitro study was undertaken to evaluate the effect of four different irrigants namely Sodium hypochlorite, Chlorhexidine, Triphala and Morinda citrifolia on the shear bond strength of a self etch sealer, Real Seal SE to dentin by using with and without EDTA as the final irrigant using an Universal Testing Machine.
The study was done using one hundred and twenty extracted maxillary and mandibular human molars. A low speed diamond disk saw with Water coolant was used to slice off the occlusal 2mm of the samples whereby a flat dentinal surface surrounded by a thin rim of enamel was obtained. This section of tooth, which included the roots, were embedded in a self cure acrylic resin. A smear layer was created on the sectioned teeth using a 320 grit silicon carbide paper on a Handimet grinder (Buehler, Ltd) under Water irrigation for a time period of 15 seconds. The dentin disks with the smear layer were then randomly divided into 2 groups namely Group I-without EDTA and Group II-with EDTA. Each of the Group was further divided into four Subgroups namely Sodium hypochlorite, Morinda citrifolia, Triphala and Chlorhexidine respectively.
The dentin discs were air dried using a air-water syringe. A brass tube of 4mm internal diameter and 3mm height was placed onto the dentin surface. The brass tube was filled with Real Seal SE, (Fig.4H) which was mixed according to the manufacturer’s instructions. The sealer was then
light cured using a light curing unit (QHL-75,Dentsply) for 40 seconds and allowed to set for forty five minutes. The samples were immediately stored in distilled water at 37oC and maintained at 100% humidity for 7 days.
The specimens were then engaged perpendicularly at their bases on a Universal Testing Machine (INSTRON 3365). Each specimen was evaluated for its shear bond strength values, at a cross head speed of 1mm/minute. The shear force required to separate the cylinder from dentin was recorded in Newtons (N) for each specimen, then divided by contact surface area to determine the shear bond strength in Megapascals. The results were then statistically analyzed using a paired One way ANOVA, Students ‘T’ test and Duncan’s Multiple Range Test. The results revealed that Subgroup Sodium hypochlorite had the highest shear bond strength in Group I (without EDTA) and Group II (with EDTA) followed in order by Subgroups Morinda citrifolia, Triphala and Chlorhexidine in both groups. When both Group I and Group II were compared, the Group II (with EDTA), all the Subgroups showed highest bond strength to dentin with resin sealer (Real Seal SE).
CONCLUSION:
Within the limitations of the study it can be concluded that 1. Sodium hypochlorite Subgroup in both the Group I (without EDTA) and Group II (with EDTA) showed the maximum shear bond strength values.
2. Chlorhexidine Subgroup in both the Group I (without EDTA) and Group II (with EDTA) showed the minimum shear bond strength values.
3.Triphala and Morinda citrifolia Subgroups showed shear bond strength values more than Chlorhexidine but less than Sodium hypochlorite in both the groups.
4. Triphala and Morinda citrifolia could be used as herbal alternative irrigants during the cleaning and shaping of the root canals. It is seen that they are as effective but are less toxic and more biocompatible than the traditionally used irrigants.
5. Further studies with more parameters are necessary to validate these results and to determine the suitability of this material for invivo use
Universal Extra Dimensions and the Graviton Portal to Dark Matter
The Universal Extra Dimension (UED) paradigm is particularly attractive as it
not only includes a natural candidate for the Dark Matter particle but also
addresses several issues related to particle physics. Non-observations at the
Large Hadron Collider, though, has brought the paradigm into severe tension.
However, a particular 5-dimensional UED model emerges from a six-dimensional
space-time with nested warping. The bulk protects both the Higgs mass
as well as the UED scale without invoking unnatural parameter values. The
graviton excitations in the sixth direction open up new (co-)annihilation
channels for the Dark Matter particle, thereby allowing for phenomenological
consistency, otherwise denied to the minimal UED scenario. The model leads to
unique signatures in both satellite-based experiments as well as the LHC.Comment: 16 pages, 4 figures, To be published in JCA
Graviton modes in multiply warped geometry
The negative results in the search for Kaluza-Klein graviton modes at the
LHC, when confronted with the discovery of the Higgs, has been construed to
have severely limited the efficacy of the Randall-Sundrum model as an
explanation of the hierarchy problem. We show, though, that the presence of
multiple warping offers a natural resolution of this conundrum through
modifications in both the graviton spectrum and their couplings to the Standard
Model fields.Comment: 16 pages, 6 figure
Skyrmion in teleparallel gravity
The Einstein-Skyrme system became famous for its black hole solutions that
admits fractional baryon number outside the horizon, thus violating the "{\it
no hair}" conjecture. In this article, we extend the Skyrmion to teleparallel
gravity framework and investigate the teleparallel-Skyrme system in the context
of the Teleparallel Equivalent of General Relativity (TEGR) and power
law gravity. We demonstrate the emergence of the fractional baryon number
outside the horizon and its dependence on the cosmological constant
(). The solutions in TEGR (), as expected, matches
with the Einstein-Skyrme system with the requirement of .
Interestingly, in power law gravity (), the
reality conditions requires the cosmological constant to be positive and stay
within the range . And, in the limit
power law gravity reaches TEGR (), we get back the
condition on the cosmological constant with and
.Comment: 19 pages, 6 figure
Living Orthogonally: Quasi-universal Extra Dimensions
The minimal Universal Extra Dimension scenario is highly constrained owing to
opposing constraints from the observed relic density on the one hand, and the
non-observation of new states at the LHC on the other. Simple extensions in
five-dimensions can only postpone the inevitable. Here, we propose a
six-dimensional alternative with the key feature being that the SM quarks and
leptons are localized on orthogonal directions whereas gauge bosons traverse
the entire bulk. Several different realizations of electroweak symmetry
breaking are possible, while maintaining agreement with low energy observables.
This model is not only consistent with all the current constraints opposing the
minimal Universal Extra Dimension scenario but also allows for a multi-TeV dark
matter particle without the need for any fine-tuning. In addition, it promises
a plethora of new signatures at the LHC and other future experiments.Comment: 43 pages, 5 figures, accepted for publication in JHE
Constraining SMEFT BSM scenarios with EWPO and
Precision observables are well known for constraining most of the Beyond
Standard Model (BSM) scenarios tightly. We present here a simple and
comprehensive fitting framework for various BSM scenarios to these observables.
We start with the fit of , and parameter and their correlations
using the Electroweak Precision Observables (EWPO) including the recent
measurement from CDF-II. Utilizing these observables, we also fit various New
Physics (NP) scenarios consisting of different subsets of dimension-6 Standard
Model Effective Field Theory (SMEFT) operators out of a total of 10 appearing
at tree level in EWPO. To further constrain these scenarios, we augment these
observables with measurement using 1-loop matching of the Low
Energy Effective Field Theory (LEFT) to SMEFT operators at the Z-pole. We show
that the inclusion of constraint indeed results in stronger
bounds on the SMEFT Wilson Coefficients. We also constrain the UV parameters of
BSM extensions like Vectorlike leptons (VLL) and find out that such a minimal
extension is in tension with the forward-backward asymmetry in -sector
() and the recent measurement of . In order to lift the two
blind directions, which one encounters while fitting all the 10 SMEFT WCs at
tree-level, we also include the LEP-II observables pertaining to the
production and present the results for the fits with and without
constraint.Comment: 32 pages, 6 figures, 19 table
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