scholarly journals Dark matter detection, Standard Model parameters and Intermediate Scale Supersymmetry

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
David Dunsky ◽  
Lawrence J. Hall ◽  
Keisuke Harigaya
Keyword(s):  
Dark Matter ◽  
Strong Coupling ◽  
Top Quark ◽  
Quark Mass ◽  
Strong Coupling Constant ◽  
Model Parameters ◽  
Coupling Constant ◽  
Top Quark Mass ◽  
Intermediate Scale ◽  
Dark Matter Mass

Abstract The vanishing of the Higgs quartic coupling at a high energy scale may be explained by Intermediate Scale Supersymmetry, where supersymmetry breaks at (109-1012) GeV. The possible range of supersymmetry breaking scales can be narrowed down by precise measurements of the top quark mass and the strong coupling constant. On the other hand, nuclear recoil experiments can probe Higgsino or sneutrino dark matter up to a mass of 1012 GeV. We derive the correlation between the dark matter mass and precision measurements of standard model parameters, including supersymmetric threshold corrections. The dark matter mass is bounded from above as a function of the top quark mass and the strong coupling constant. The top quark mass and the strong coupling constant are bounded from above and below respectively for a given dark matter mass. We also discuss how the observed dark matter abundance can be explained by freeze-out or freeze-in during a matter-dominated era after inflation, with the inflaton condensate being dissipated by thermal effects.

scholarly journals Neutrino masses, vacuum stability and quantum gravity prediction for the mass of the top quark

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Guillem Domènech ◽  
Mark Goodsell ◽  
Christof Wetterich
Keyword(s):  
Quantum Gravity ◽  
Top Quark ◽  
Quark Mass ◽  
Scalar Potential ◽  
Planck Scale ◽  
Neutrino Masses ◽  
Top Quark Mass ◽  
Vacuum Stability ◽  
Intermediate Scale ◽  
Yukawa Couplings

Abstract A general prediction from asymptotically safe quantum gravity is the approximate vanishing of all quartic scalar couplings at the UV fixed point beyond the Planck scale. A vanishing Higgs doublet quartic coupling near the Planck scale translates into a prediction for the ratio between the mass of the Higgs boson MH and the top quark Mt. If only the standard model particles contribute to the running of couplings below the Planck mass, the observed MH∼ 125 GeV results in the prediction for the top quark mass Mt∼ 171 GeV, in agreement with recent measurements. In this work, we study how the asymptotic safety prediction for the top quark mass is affected by possible physics at an intermediate scale. We investigate the effect of an SU(2) triplet scalar and right-handed neutrinos, needed to explain the tiny mass of left-handed neutrinos. For pure seesaw II, with no or very heavy right handed neutrinos, the top mass can increase to Mt ∼ 172.5 GeV for a triplet mass of M∆ ∼ 108GeV. Right handed neutrino masses at an intermediate scale increase the uncertainty of the predictions of Mt due to unknown Yukawa couplings of the right-handed neutrinos and a cubic interaction in the scalar potential. For an appropriate range of Yukawa couplings there is no longer an issue of vacuum stability.

scholarly journals Optimising top-quark threshold scan at CLIC using genetic algorithm

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
K. Nowak ◽  
A.F. Żarnecki
Keyword(s):  
Genetic Algorithm ◽  
Pair Production ◽  
Top Quark ◽  
Quark Mass ◽  
Mass Measurement ◽  
Production Cross ◽  
Model Parameters ◽  
Top Quark Mass ◽  
Systematic Uncertainties ◽  
Pair Production Cross Section

Abstract One of the important goals at the future e+e− colliders is to measure the top-quark mass and width in a scan of the pair production threshold. However, the shape of the pair-production cross section at the threshold depends also on other model parameters, as the top Yukawa coupling, and the measurement is a subject to many systematic uncertainties. Presented in this work is the study of the top-quark mass determination from the threshold scan at CLIC. The most general approach is used with all relevant model parameters and selected systematic uncertainties included in the fit procedure. Expected constraints from other measurements are also taken into account. It is demonstrated that the top-quark mass can be extracted with precision of the order of 30 to 40 MeV, including considered systematic uncertainties, already for 100 fb−1 of data collected at the threshold. Additional improvement is possible, if the running scenario is optimised. With the optimisation procedure based on the genetic algorithm the statistical uncertainty of the mass measurement can be reduced by about 20%. Influence of the collider luminosity spectra on the expected precision of the measurement is also studied.

scholarly journals Calculations for deep inelastic scattering using fast interpolation grid techniques at NNLO in QCD and the extraction of $$\alpha _{\mathrm {s}}$$ from HERA data

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
D. Britzger ◽  
J. Currie ◽  
A. Gehrmann-De Ridder ◽  
T. Gehrmann ◽  
E. W. N. Glover ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Deep Inelastic Scattering ◽  
Strong Coupling ◽  
Distribution Functions ◽  
Strong Coupling Constant ◽  
Model Parameters ◽  
Coupling Constant ◽  
Section Data ◽  
Inclusive Jet ◽  
Interpolation Grid

Abstract The extension of interpolation-grid frameworks for perturbative QCD calculations at next-to-next-to-leading order (NNLO) is presented for deep inelastic scattering (DIS) processes. A fast and flexible evaluation of higher-order predictions for any a posteriori choice of parton distribution functions (PDFs) or value of the strong coupling constant is essential in iterative fitting procedures to extract PDFs and Standard Model parameters as well as for a detailed study of the scale dependence. The APPLfast project, described here, provides a generic interface between the parton-level Monte Carlo program NNLOjet and both the APPLgrid and fastNLO libraries for the production of interpolation grids at NNLO accuracy. Details of the interface for DIS processes are presented together with the required interpolation grids at NNLO, which are made available. They cover numerous inclusive jet measurements by the H1 and ZEUS experiments at HERA. An extraction of the strong coupling constant is performed as an application of the use of such grids and a best-fit value of $$\alpha _{\mathrm {s}} (M_{{\mathrm {Z}}}) = 0.1170\,(15)_\text {exp}\,(25)_\text {th}$$αs(MZ)=0.1170(15)exp(25)th is obtained using the HERA inclusive jet cross section data.

scholarly journals Determination of the top-quark pole mass and strong coupling constant from the tt¯ production cross section in pp collisions at s=7 TeV

2014 ◽  
Vol 728 ◽  
pp. 496-517 ◽  
Author(s):  
S. Chatrchyan ◽  
V. Khachatryan ◽  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Cross Section ◽  
Top Quark ◽  
Production Cross Section ◽  
Production Cross ◽  
Strong Coupling Constant ◽  
Pole Mass ◽  
Coupling Constant ◽  
Pp Collisions

STABILITY OF THE TOP QUARK MASS IN SUPERSYMMETRIC TOP CONDENSATE MODELS

1991 ◽  
Vol 06 (35) ◽  
pp. 3225-3237 ◽  
Author(s):  
T. E. CLARK ◽  
S. T. LOVE ◽  
W. T. A. TER VELDHUIS
Keyword(s):  
Fixed Point ◽  
Renormalization Group ◽  
Yukawa Coupling ◽  
Top Quark ◽  
Quark Mass ◽  
Coupling Constant ◽  
Top Quark Mass ◽  
Higher Dimensional

The top quark mass prediction in supersymmetric top condensate models is found to be insensitive to the inclusion of the effects of higher dimensional operators. For associated coefficients of characteristically moderate strength, the supersymmetric renormalization group trajectories are strongly focused to the infrared quasi-fixed point of the top Yukawa coupling constant.

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