4,673 research outputs found
Hadron Collider Sensitivity to Fat Flavourful s for
We further investigate the case where new physics in the form of a massive
particle explains apparent measurements of lepton flavour
non-universality in decays. Hadron collider
sensitivities for direct production of such s have been previously
studied in the narrow width limit for a final state. Here, we
extend the analysis to sizeable decay widths and improve the sensitivity
estimate for the narrow width case. We estimate the sensitivities of the high
luminosity 14 TeV Large Hadron Collider (HL-LHC), a high energy 27 TeV LHC
(HE-LHC), as well as a potential 100 TeV future circular collider (FCC). The
HL-LHC has sensitivity to narrow resonances consistent with the
anomalies. In one of our simplified models the FCC could probe 23 TeV
particles with widths of up to 0.35 of their mass at 95\% confidence
level (CL). In another model, the HL-LHC and HE-LHC cover sizeable portions of
parameter space, but the whole of perturbative parameter space can be covered
by the FCC.Comment: 24 pages, 11 figures; v2 Reference
A rapid graphical technique for obtaining radar data time history for close earth orbits
Radar tracking parameters and contact time errors from graphic estimation of radar tracking coverage of near earth orbit
Investigation of critical slowing down in a bistable S-SEED
A simulation of S-SEED switching based upon experimental data is developed that includes the effect of critical slowing down. The simulation's accuracy is demonstrated by close agreement with the results from experimental S-SEED switching. The simulation is subsequently used to understand how the phenomenon of critical slowing down applies to switching of an S-SEED and how the effect on photonic analog-to-digital (A/D) converter performance may be minimized.B. A. Clare, K. A. Corbett, K. J. Grant, P. B. Atanackovic, W. Marwood and J. Munc
Modeling of radiation damage in silicon solar cells
One MeV electron irradiation produces preponderantly isolated vacancy interstitial pairs. If neither of these defects is mobile, the concentration of each grows linearly with fluence. Annealing of damage depends on the nature of the damage. Vacancy interstitial pairs which are bound by an interaction such that they mutually annihilate rather than dissociate are termed close pairs; close pair recovery usually occurs at a lower temperature than the temperature at which long distance defect migration occurs. Annealing of the remaining frozen in damage occurs when a temperature is reached where the vacancy or interstitial is mobile; usually the interstitial is more mobile than the vacancy. The recovery occurs in two regimes which may be resoluable
The effectiveness of faecal removal methods of pasture management to control the cyathostomin burden of donkeys
Background:
The level of anthelmintic resistance within some cyathostomin parasite populations has increased to the level where sole reliance on anthelmintic-based control protocols is not possible. Management-based nematode control methods, including removal of faeces from pasture, are widely recommended for use in association with a reduction in anthelmintic use to reduce selection pressure for drug resistance; however, very little work has been performed to quantitatively assess the effectiveness of such methods.<p></p>
Methods:
We analysed data obtained from 345 donkeys at The Donkey Sanctuary (Devon, UK), managed under three different pasture management techniques, to investigate the effectiveness of faeces removal in strongyle control in equids. The management groups were as follows: no removal of faeces from pasture, manual, twice-weekly removal of faeces from pasture and automatic, twice-weekly removal of faeces from pasture (using a mechanical pasture sweeper). From turn-out onto pasture in May, monthly faecal egg counts were obtained for each donkey and the dataset subjected to an auto regressive moving average model.<p></p>
Results:
There was little to no difference in faecal egg counts between the two methods of faecal removal; both resulted in significantly improved cyathostomin control compared to the results obtained from the donkeys that grazed pasture from which there was no faecal removal.<p></p>
Conclusions:
This study represents a valuable and unique assessment of the effectiveness of the removal of equine faeces from pasture, and provides an evidence base from which to advocate twice-weekly removal of faeces from pasture as an adjunct for equid nematode control. Widespread adoption of this practice could substantially reduce anthelmintic usage, and hence reduce selection pressure for nematode resistance to the currently effective anthelmintic products.<p></p>
CT and hemifacial spasm.
Journal ArticleForty-six patients with typical hemifacial spasm had CT. Thirty-eight (83%) were abnormal, including two with surgically documented tumors. Thirty-six had a characteristic dolichoectatic vertebrobasilar artery, with the convexity pointing to the side of the spasm in 92% of the scans. This study suggests that CT is worthwhile procedure in the evaluation of hemifacial spasm and that dolichoectatic vertebrobasilar arteries are very frequently associated with hemifacial spasm
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Collider constraints on Z ′ models for neutral current B-anomalies
Abstract: We examine current collider constraints on some simple Z′ models that fit neutral current B-anomalies, including constraints coming from measurements of Standard Model (SM) signatures at the LHC. The ‘MDM’ simplified model is not constrained by the SM measurements but is strongly constrained by a 139 fb−1 13 TeV ATLAS di-muon search. Constraints upon the ‘MUM’ simplified model are much weaker. A combination of the current Bs mixing constraint and ATLAS’ Z′ search implies MZ′>1.2 TeV in the Third Family Hypercharge Model example case. LHC SM measurements rule out a portion of the parameter space of the model for MZ′>1.5 TeV
Disentangling a dynamical Higgs
The pattern of deviations from Standard Model predictions and couplings is
different for theories of new physics based on a non-linear realization of the
gauge symmetry breaking and those assuming a linear
realization. We clarify this issue in a model-independent way via its effective
Lagrangian formulation in the presence of a light Higgs particle, up to first
order in the expansions: dimension-six operators for the linear expansion and
four derivatives for the non-linear one. Complete sets of pure gauge and
gauge-Higgs operators are considered, implementing the renormalization
procedure and deriving the Feynman rules for the non-linear expansion. We
establish the theoretical relation and the differences in physics impact
between the two expansions. Promising discriminating signals include the
decorrelation in the non-linear case of signals correlated in the linear one:
some pure gauge versus gauge-Higgs couplings and also between couplings with
the same number of Higgs legs. Furthermore, anomalous signals expected at first
order in the non-linear realization may appear only at higher orders of the
linear one, and vice versa. We analyze in detail the impact of both type of
discriminating signals on LHC physics.Comment: Version published in JHE
Anomalous Hall Effect in three ferromagnets: EuFe4Sb12, Yb14MnSb11, and Eu8Ga16Ge30
The Hall resistivity (Rho_xy), resistivity (Rho_xx), and magnetization of
three metallic ferromagnets are investigated as a function of magnetic field
and temperature. The three ferromagnets, EuFe4Sb12 (Tc = 84 K), Yb14MnSb11 (Tc
= 53 K), and Eu8Ga16Ge30 (Tc = 36 K) are Zintl compounds with carrier
concentrations between 1 x 10^21 cm^-3 and 3.5 x 10^21 cm^-3. The relative
decrease in Rho_xx below Tc [Rho_xx(Tc)/Rho_xx(2 K)] is 28, 6.5, and 1.3 for
EuFe4Sb12, Yb14MnSb11, and Eu8Ga16Ge30 respectively. The low carrier
concentrations coupled with low magnetic anisotropies allow a relatively clean
separation between the anomalous (Rho_'xy), and normal contributions to the
measured Hall resistivity. For each compound the anomalous contribution in the
zero field limit is fit to alpha Rho_xx + sigma_xy rho_xx^2 for temperatures T
< Tc. The anomalous Hall conductivity, sigma_xy, is -220 +- 5 (Ohm^-1 cm^-1),
-14.7 +- 1 (Ohm^-1 cm^-1), and 28 +- 3 (Ohm^-1 cm^-1) for EuFe4Sb12,
Yb14MnSb11, and Eu8Ga16Ge30 respectively and is independent of temperature for
T < Tc if the change in spontaneous magnetization (order parameter) with
temperature is taken into account. These data are consistent with recent
theories of the anomalous Hall effect that suggest that even for stochiometric
ferromagnetic crystals, such as those studied in this article, the intrinsic
Hall conductivity is finite at T = 0, and is a ground state property that can
be calculated from the electronic structure.Comment: 22 pages, 13 figures Submitted to PR
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