scholarly journals Higgs vacuum decay in a braneworld

2019 ◽  
Vol 29 (01) ◽  
pp. 2050005 ◽  
Author(s):  
Leopoldo Cuspinera ◽  
Ruth Gregory ◽  
Katie M. Marshall ◽  
Ian G. Moss
Keyword(s):  
Scalar Field ◽  
Standard Model ◽  
Extra Dimension ◽  
Numerical Solutions ◽  
Large Extra Dimensions ◽  
De Sitter ◽  
Vacuum Decay ◽  
Instanton Action ◽  
Realistic Potential ◽  
The Standard Model

We examine the effect of large extra dimensions on vacuum decay in the Randall–Sundrum (RS) braneworld paradigm. We assume the scalar field is confined to the brane, and compute the probability for forming an “anti-de Sitter” (AdS) bubble inside a critical flat RS brane. We present the first full numerical solutions for the brane instanton considering two test potentials for the scalar field. We explore the geometrical impact of thin and thick bubble walls, and compute the instanton action in a range of cases. We conclude by commenting on a more physically realistic potential relevant for the Standard Model Higgs. For bubbles with large backreaction, the extra dimension has a dramatic effect on the tunnelling rate, however, for the weakly backreacting bubbles more relevant for realistic Standard Model potentials, the extra dimension has little impact.

scholarly journals On catalyzed vacuum decay around a radiating black hole and the crisis of the electroweak vacuum

2020 ◽  
Vol 2020 (8) ◽  
Author(s):  
Takumi Hayashi ◽  
Kohei Kamada ◽  
Naritaka Oshita ◽  
Jun’ichi Yokoyama
Keyword(s):  
Black Hole ◽  
Scalar Field ◽  
Standard Model ◽  
Decay Rate ◽  
Early Universe ◽  
Hawking Radiation ◽  
False Vacuum ◽  
Vacuum Decay ◽  
Higgs Vacuum ◽  
The Standard Model

Abstract False vacuum decay is a key feature in quantum field theories and exhibits a distinct signature in the early Universe cosmology. It has recently been suggested that the false vacuum decay is catalyzed by a black hole (BH), which might cause the catastrophe of the Standard Model Higgs vacuum if primordial BHs are formed in the early Universe. We investigate vacuum phase transition of a scalar field around a radiating BH with taking into account the effect of Hawking radiation. We find that the vacuum decay rate slightly decreases in the presence of the thermal effect since the scalar potential is stabilized near the horizon. However, the stabilization effect becomes weak at the points sufficiently far from the horizon. Consequently, we find that the decay rate is not significantly changed unless the effective coupling constant of the scalar field to the radiation is extremely large. This implies that the change of the potential from the Hawking radiation does not help prevent the Standard Model Higgs vacuum decay catalyzed by a BH.

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.

Cosmic-ray induced vacuum decay in the standard model

1988 ◽  
Vol 206 (3) ◽  
pp. 527-532 ◽  
Author(s):  
Marc Sher ◽  
Helmut W. Zaglauer
Keyword(s):  
Standard Model ◽  
Cosmic Ray ◽  
Vacuum Decay ◽  
The Standard Model

scholarly journals Physics Beyond The Standard Model: Experimental

2001 ◽  
Vol 16 (supp01a) ◽  
pp. 92-103 ◽  
Author(s):  
R. L. Culbertson
Keyword(s):  
Standard Model ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
High Energy ◽  
Higgs Bosons ◽  
Beyond The Standard Model ◽  
The Standard Model ◽  
Model Independent

The search for physics beyond the Standard Model includes Technicolor particles, Higgs Bosons, compositeness, many variations of Supersymmetry, large extra dimensions, model-independent searches for anomalies, and other topics. This article reports a subset of these ongoing searches at the high-energy colliders, Tevatron, HERA and LEP.

scholarly journals A DARK SECTOR EXTENSION OF THE ALMOST-COMMUTATIVE STANDARD MODEL

2014 ◽  
Vol 29 (01) ◽  
pp. 1450005 ◽  
Author(s):  
CHRISTOPH A. STEPHAN
Keyword(s):  
Scalar Field ◽  
Standard Model ◽  
Present Model ◽  
Higgs Field ◽  
Dark Sector ◽  
Spectral Action ◽  
Scalar Particles ◽  
A Value ◽  
The Standard Model ◽  
Model C

We consider an extension of the Standard Model within the framework of Noncommutative Geometry. The model is based on an older model [C. A. Stephan, Phys. Rev. D79, 065013 (2009)] which extends the Standard Model by new fermions, a new U(1)-gauge group and, crucially, a new scalar field which couples to the Higgs field. This new scalar field allows to lower the mass of the Higgs mass from ~170 GeV, as predicted by the Spectral Action for the Standard Model, to a value of 120–130 GeV. The shortcoming of the previous model lay in its inability to meet all the constraints on the gauge couplings implied by the Spectral Action. These shortcomings are cured in the present model which also features a "dark sector" containing fermions and scalar particles.

scholarly journals The Standard Model with one universal extra dimension

Pramana ◽  
2013 ◽  
Vol 80 (3) ◽  
pp. 369-412 ◽  
Author(s):  
A CORDERO-CID ◽  
M GÓMEZ-BOCK ◽  
H NOVALES-SÁNCHEZ ◽  
J J TOSCANO
Keyword(s):  
Standard Model ◽  
Extra Dimension ◽  
Universal Extra Dimension ◽  
The Standard Model

scholarly journals Quark-flavor-changing Higgs decays from a universal extra dimension

2020 ◽  
Vol 35 (24) ◽  
pp. 2050141
Author(s):  
Carlos M. Farrera ◽  
Alejandro Granados-González ◽  
Héctor Novales-Sánchez ◽  
J. Jesús Toscano
Keyword(s):  
Standard Model ◽  
Extra Dimension ◽  
New Physics ◽  
Tree Level ◽  
Universal Extra Dimension ◽  
Loop Level ◽  
Flavor Changing ◽  
The Standard Model ◽  
The One ◽  
Kaluza Klein

Kaluza–Klein fields characterizing, from a four-dimensional viewpoint, the presence of compact universal extra dimensions would alter low-energy observables through effects determined by some compactification scale, [Formula: see text], since the one-loop level, thus being particularly relevant for physical phenomena forbidden at tree level by the Standard Model. This paper explores, for the case of one universal extra dimension, such new-physics contributions to Higgs decays [Formula: see text], into pairs of quarks with different flavors, a sort of decay process which, in the Standard Model, strictly occurs at the loop level. Finite results, decoupling as [Formula: see text], are calculated. Approximate short expressions, valid for large compactification scales, are provided. We estimate that Kaluza–Klein contributions lie below predictions from the Standard Model, being about 2 to 3 orders of magnitude smaller for compactification scales within [Formula: see text].

STRONG CP PROBLEM AND AN AXIAL U(1) GAUGE SYMMETRY

1993 ◽  
Vol 08 (32) ◽  
pp. 3049-3056
Author(s):  
PONG YOUL PAC ◽  
CHERL SOO PAHK
Keyword(s):  
Scalar Field ◽  
Gauge Symmetry ◽  
Standard Model ◽  
Degree Of Freedom ◽  
New Approach ◽  
The Standard Model ◽  
Massless Quark ◽  
Exact Term ◽  
Physical Degree

We extend the standard model by an axial U(1) gauge symmetry obtained from a rotation parametrized by a scalar field. In quantizing the system, the Peccei-Quinn symmetry is realized by introducing a BRST-exact term, which can provide a new approach to the strong CP problem without assuming a physical degree of freedom like the axion or the massless quark. We can find that the transition between different topological sectors of QCD via physical scattering processes is suppressed.

FROM EXTRA-DIMENSIONS: MULTIPLE BRANE SCENARIOS AND THEIR CONTENDERS

2010 ◽  
Vol 25 (32) ◽  
pp. 5817-5845
Author(s):  
IGNATIOS ANTONIADIS
Keyword(s):  
Standard Model ◽  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Particle Accelerators ◽  
Mass Hierarchy ◽  
Beyond The Standard Model ◽  
Microgravity Experiments ◽  
The Standard Model

We first discuss the problem of mass hierarchy and review briefly the main Beyond the Standard Model (BSM) proposals. We then describe the framework of strings, branes and large extra dimensions and give the main experimental predictions in both particle accelerators and microgravity experiments testing gravity at short distances. Finally, we present some models based on intersecting branes and discuss the issue of Standard Model embedding.

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