scholarly journals MUON ANOMALY AND A LOWER BOUND ON HIGGS MASS DUE TO A LIGHT STABILIZED RADION IN THE RANDALL–SUNDRUM MODEL

2006 ◽  
Vol 21 (26) ◽  
pp. 5205-5220 ◽  
Author(s):  
PRASANTA KUMAR DAS
Keyword(s):  
Lower Bound ◽  
Extra Dimension ◽  
Higgs Mass ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Quartic Coupling ◽  
Muon Anomalous Magnetic Moment ◽  
Expectation Value ◽  
The Standard Model ◽  
Standard Model Result

We investigate the Randall–Sundrum model with a light stabilized radion (required to fix the size of the extra dimension) in the light of muon anomalous magnetic moment [Formula: see text]. Using the recent data (obtained from the E821 experiment of the BNL Collaboration) which differs by 2.6σ from the Standard Model result, we obtain constraints on radion mass mϕ and radion vacuum expectation value 〈ϕ〉. In the presence of a radion the beta functions β(λ) and β(gt) of Higgs quartic coupling (λ) and top-Yukawa coupling (gt) gets modified. We find these modified beta functions. Using these beta functions together with the anomaly constrained mϕ and 〈ϕ〉, we obtain lower bound on Higgs mass mh. We compare our result with the present LEP2 bound on mh.

$B_0\bar B_0$-Mixing Involving Supersymmetry

1997 ◽  
Vol 12 (06) ◽  
pp. 419-426 ◽  
Author(s):  
J. Urban ◽  
F. Krauss ◽  
Ch. Hofmann ◽  
G. Soff
Keyword(s):  
Standard Model ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Higgs Mass ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Feynman Diagrams ◽  
Lower Edge ◽  
Expectation Value ◽  
The Standard Model

We calculate all relevant Feynman-diagrams in lowest order for [Formula: see text]-mixing. We add to the Standard Model (SM) two scalar Higgs-doublets and take into account the Minimal Supersymmetric Standard Model (MSSM). Within the Standard Model which has been extended by two Higgs-doublets we find the following relation between the Higgs-mass and its vacuum expectation value (vev): mH=5000/7(au-0.43). Inclusion of the MSSM pushes the value of Vtd to the lower edge of the experimentally allowed range.

scholarly journals Weak scale from Planck scale: Mass scale generation in a classically conformal two-scalar system

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
Junichi Haruna ◽  
Hikaru Kawai
Keyword(s):  
Scalar Field ◽  
Standard Model ◽  
Planck Scale ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
The Other ◽  
Expectation Value ◽  
Weak Scale ◽  
The Standard Model ◽  
The One

Abstract In the standard model, the weak scale is the only parameter with mass dimensions. This means that the standard model itself cannot explain the origin of the weak scale. On the other hand, from the results of recent accelerator experiments, except for some small corrections, the standard model has increased the possibility of being an effective theory up to the Planck scale. From these facts, it is naturally inferred that the weak scale is determined by some dynamics from the Planck scale. In order to answer this question, we rely on the multiple point criticality principle as a clue and consider the classically conformal $\mathbb{Z}_2\times \mathbb{Z}_2$ invariant two-scalar model as a minimal model in which the weak scale is generated dynamically from the Planck scale. This model contains only two real scalar fields and does not contain any fermions or gauge fields. In this model, due to a Coleman–Weinberg-like mechanism, the one-scalar field spontaneously breaks the $ \mathbb{Z}_2$ symmetry with a vacuum expectation value connected with the cutoff momentum. We investigate this using the one-loop effective potential, renormalization group and large-$N$ limit. We also investigate whether it is possible to reproduce the mass term and vacuum expectation value of the Higgs field by coupling this model with the standard model in the Higgs portal framework. In this case, the one-scalar field that does not break $\mathbb{Z}_2$ can be a candidate for dark matter and have a mass of about several TeV in appropriate parameters. On the other hand, the other scalar field breaks $\mathbb{Z}_2$ and has a mass of several tens of GeV. These results will be verifiable in near-future experiments.

scholarly journals Electroweak Phase Transitions in Einstein’s Static Universe

2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
M. Gogberashvili
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Electroweak Phase Transition ◽  
Static Universe ◽  
Expectation Value ◽  
First Order ◽  
Higgs Vacuum ◽  
The Standard Model ◽  
Effective Reduction ◽  
New Phase

We suggest using Einstein’s static universe metric for the metastable state after reheating, instead of the Friedman-Robertson-Walker spacetime. In this case, strong static gravitational potential leads to the effective reduction of the Higgs vacuum expectation value, which is found to be compatible with the Standard Model first-order electroweak phase transition conditions. Gravity could also increase the CP-violating effects for particles that cross the new phase bubble walls and thus is able to lead to the successful electroweak baryogenesis scenario.

scholarly journals A model with isospin doublet U(1)D gauge symmetry

2018 ◽  
Vol 33 (14n15) ◽  
pp. 1850089 ◽  
Author(s):  
Takaaki Nomura ◽  
Hiroshi Okada
Keyword(s):  
Gauge Symmetry ◽  
Global Analysis ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Dark Matter Candidate ◽  
Expectation Value ◽  
Lepton Flavor ◽  
Stringent Constraint ◽  
The Standard Model ◽  
Gauge Anomalies

We propose a model with an extra isospin doublet [Formula: see text] gauge symmetry, in which we introduce several extra fermions with odd parity under a discrete [Formula: see text] symmetry in order to cancel the gauge anomalies out. A remarkable issue is that we impose nonzero [Formula: see text] charge to the Standard Model Higgs, and it gives the most stringent constraint to the vacuum expectation value of a scalar field breaking the [Formula: see text] symmetry that is severer than the LEP bound. We then explore relic density of a Majorana dark matter candidate without conflict of constraints from lepton flavor violating processes. A global analysis is carried out to search for parameters which can accommodate with the observed data.

scholarly journals UTILITY OF A SPECIAL SECOND SCALAR DOUBLET

2008 ◽  
Vol 23 (09) ◽  
pp. 647-652 ◽  
Author(s):  
ERNEST MA
Keyword(s):  
Dark Matter ◽  
Standard Model ◽  
Neutrino Mass ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Grand Unification ◽  
Particle Interactions ◽  
Expectation Value ◽  
The Standard Model

This review deals with the recent resurgence of interest in adding a second scalar doublet (η+, η0) to the Standard Model of particle interactions. In most studies, it is taken for granted that η0 should have a nonzero vacuum expectation value, even if it may be very small. What if there is an exactly conserved symmetry which ensures 〈η0 〉 = 0? The phenomenological ramifications of this idea include dark matter, radiative neutrino mass, leptogenesis, and grand unification.

scholarly journals Left–right model from gauge-Higgs unification with dark matter

2015 ◽  
Vol 30 (12) ◽  
pp. 1550063 ◽  
Author(s):  
Francisco J. de Anda
Keyword(s):  
Dark Matter ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Dark Matter Candidate ◽  
Symmetric Model ◽  
Dimensional Model ◽  
Expectation Value ◽  
Fermion Masses ◽  
The Standard Model ◽  
Five Dimensional Model

We propose a five-dimensional model based on the idea of Gauge-Higgs Unification (GHU) with the gauge group SO(5) × U(1) in Randall–Sundrum (RS) spacetime. We obtain a left–right (LR) symmetric model with a stable scalar identified as a dark matter candidate. This stable scalar obtains a vacuum expectation value (VEV) that gives mass to fermions in the bulk through the Hosotani Mechanism. There is a scalar localized on a brane and gives contributions to fermion masses. This scalar fits the observed Higgs boson data. We are able to fit all the Standard Model (SM) observables while evading constraints.

Global symmetries and Noether’s theorem

2018 ◽  
Author(s):  
Michael Kachelriess
Keyword(s):  
Global Symmetries ◽  
Symmetry Transformation ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Quantum Field ◽  
Expectation Value ◽  
Minkowski Space Time ◽  
Integral Measure ◽  
Colour Charge ◽  
Internal Symmetries

Noethers theorem shows that continuous global symmetries lead classically to conservation laws. Such symmetries can be divided into spacetime and internal symmetries. The invariance of Minkowski space-time under global Poincaré transformations leads to the conservation of the four-momentum and the total angular momentum. Examples for conserved charges due to internal symmetries are electric and colour charge. The vacuum expectation value of a Noether current is shown to beconserved in a quantum field theory if the symmetry transformation keeps the path-integral measure invariant.

scholarly journals THE TACHYON FIELD BELOW THE MASS BARRIER

1994 ◽  
Vol 09 (20) ◽  
pp. 3497-3502 ◽  
Author(s):  
D.G. BARCI ◽  
C.G. BOLLINI ◽  
M.C. ROCCA
Keyword(s):  
Green Function ◽  
Eigenvalue Problem ◽  
Plane Wave ◽  
Time Evolution ◽  
Mass Parameter ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Tachyon Field ◽  
Expectation Value ◽  
Wave Solutions

We consider a tachyon field whose Fourier components correspond to spatial momenta with modulus smaller than the mass parameter. The plane wave solutions have then a time evolution which is a real exponential. The field is quantized and the solution of the eigenvalue problem for the Hamiltonian leads to the evaluation of the vacuum expectation value of products of field operators. The propagator turns out to be half-advanced and half-retarded. This completes the proof4 that the total propagator is the Wheeler Green function.4,7

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