scholarly journals Gravity Loop Corrections to the Standard Model Higgs in Einstein Gravity

2017 ◽  
Vol 26 (3) ◽  
pp. 229 ◽  
Author(s):  
Masaatsu Horikoshi ◽  
Yugo Abe ◽  
Takeo Inami

We study one-loop quantum gravity corrections to the standard model Higgs potential \(V(\phi) \grave{\rm a}\) la Coleman-Weinberg and examine the stability question of \(V(\phi) \) in the energy region of Planck mass scale, \(\mu\simeq M_{\rm Pl}\) \((M_{\rm Pl}=1.22\times10^{19}{\rm GeV})\). We calculate the gravity one-loop corrections to \(V(\phi)\) in Einstein gravity by using the momentum cut-off \(\Lambda\). We have found that even small gravity corrections compete with the standard model term of \(V(\phi)\) and affect the stability argument of the latter part alone. This is because the latter part is nearly zero in the energy region of \(M_{\rm Pl}\).

2016 ◽  
Vol 34 (2) ◽  
pp. 02LT01 ◽  
Author(s):  
Miguel Campiglia ◽  
Rodolfo Gambini ◽  
Jorge Pullin

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Priyotosh Bandyopadhyay ◽  
Shilpa Jangid ◽  
Manimala Mitra

Abstract We consider the extension of the Standard Model (SM) with an inert Higgs doublet that also contains two or three sets of SU(2)L triplet fermions with hypercharge zero and analyze the stability of electroweak vacuum for the scenarios. The model represents a Type-III inverse seesaw mechanism for neutrino mass generation with a Dark matter candidate. An effective potential approach calculation with two-loop beta function have been carried out in deciding the fate of the electroweak vacuum. Weak gauge coupling g2 shows a different behaviour as compared to the Standard Model. The modified running of g2, along with the Higgs quartic coupling and Type-III Yukawa couplings become crucial in determining the stability of electroweak vacuum. The interplay between two and three generations of such triplet fermions reveals that extensions with two generations is favoured if we aspire for Planck scale stability. Bounds on the Higgs quartic couplings, Type-III Yukawa and number of triplet fermion generations are drawn for different mass scale of Type-III fermions. The phenomenologies of inert doublet and Type-III fermions at the LHC and other experiments are commented upon.


2006 ◽  
Vol 15 (01) ◽  
pp. 259-272
Author(s):  
TSAN UNG CHAN

Positive baryon numbers (A>0) and positive lepton numbers (L>0) characterize matter particles while negative baryon numbers and negative lepton numbers characterize antimatter particles. Matter particles and antimatter particles belong to two distinct classes of particles. Matter neutral particles are particles characterized by both zero baryon number and zero lepton number. This third class of particles includes mesons formed by a quark and an antiquark pair (a pair of matter particle and antimatter particle) and bosons which are messengers of known interactions (photons for electromagnetism, W and Z bosons for the weak interaction, gluons for the strong interaction). The antiparticle of a matter particle belongs to the class of antimatter particles, the antiparticle of an antimatter particle belongs to the class of matter particles. The antiparticle of a matter neutral particle belongs to the same class of matter neutral particles. A truly neutral particle is a particle identical with its antiparticle; it belongs necessarily to the class of matter neutral particles. All known interactions of the Standard Model conserve baryon number and lepton number; matter cannot be created or destroyed via a reaction governed by these interactions. Conservation of baryon and lepton number parallels conservation of atoms in chemistry; the number of atoms of a particular species in the reactants must equal the number of those atoms in the products. These laws of conservation valid for interaction involving matter particles are indeed valid for any particles (matter particles characterized by positive numbers, antimatter particles characterized by negative numbers, and matter neutral particles characterized by zero). Interactions within the framework of the Standard Model which conserve both matter and charge at the microscopic level cannot explain the observed asymmetry of our Universe. The strong interaction was introduced to explain the stability of nuclei: there must exist a powerful force to compensate the electromagnetic force which tends to cause protons to fly apart. The weak interaction with laws of conservation different from electromagnetism and the strong interaction was postulated to explain beta decay. Our observed material and neutral universe would signify the existence of another interaction that did conserve charge but did not conserve matter.


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
Thomas G. Rizzo

Abstract If dark matter (DM) interacts with the Standard Model (SM) via the kinetic mixing (KM) portal, it necessitates the existence of portal matter (PM) particles which carry both dark and SM quantum numbers that will appear in vacuum polarization-like loop graphs. In addition to the familiar ∼ eϵQ strength, QED-like interaction for the dark photon (DP), in some setups different loop graphs of these PM states can also induce other coupling structures for the SM fermions that may come to dominate in at least some regions of parameter space regions and which can take the form of ‘dark’ moments, e.g., magnetic dipole-type interactions in the IR, associated with a large mass scale, Λ. In this paper, motivated by a simple toy model, we perform a phenomenological investigation of a possible loop-induced dark magnetic dipole moment for SM fermions, in particular, for the electron. We show that at the phenomenological level such a scenario can not only be made compatible with existing experimental constraints for a significant range of correlated values for Λ and the dark U(1)D gauge coupling, gD, but can also lead to quantitatively different signatures once the DP is discovered. In this setup, assuming complex scalar DM to satisfy CMB constraints, parameter space regions where the DP decays invisibly are found to be somewhat preferred if PM mass limits from direct searches at the LHC and our toy model setup are all taken seriously. High precision searches for, or measurements of, the e+e− → γ + DP process at Belle II are shown to provide some of the strongest future constraints on this scenario.


2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040012
Author(s):  
M. D. Maia ◽  
V. B. Bezerra

An updated review of Kraichnan’s derivation of Einstein’s equations from quantum field theory is presented, including the period after the discovery of the Higgs mechanism and the inclusion of gravitation within the Standard Model of Fundamental Interactions.


2016 ◽  
Vol 25 (14) ◽  
pp. 1650106
Author(s):  
Deloshan Nawarajan ◽  
Matt Visser

Under normal circumstances most members of the general relativity community focus almost exclusively on the local properties of spacetime, such as the locally Euclidean structure of the manifold and the Lorentzian signature of the metric tensor. When combined with the classical Einstein field equations this gives an extremely successful empirical model of classical gravity and classical matter — at least as long as one does not ask too many awkward questions about global issues, (such as global topology and global causal structure). We feel however that this is a tactical error — even without invoking full-fledged “quantum gravity” we know that the standard model of particle physics is also an extremely good representation of some parts of empirical reality; and we had better be able to carry over all the good features of the standard model of particle physics — at least into the realm of semi-classical quantum gravity. Doing so gives us some interesting global features that spacetime should possess: On physical grounds spacetime should be space-orientable, time-orientable, and spacetime-orientable, and it should possess a globally defined tetrad (vierbein, or in general a globally defined vielbein/[Formula: see text]-bein). So on physical grounds spacetime should be parallelizable. This strongly suggests that the metric is not the fundamental physical quantity; a very good case can be made for the tetrad being more fundamental than the metric. Furthermore, a globally-defined “almost complex structure” is almost unavoidable. Ideas along these lines have previously been mooted, but much is buried in the pre- arXiv literature and is either forgotten or inaccessible. We shall revisit these ideas taking a perspective very much based on empirical physical observation.


2012 ◽  
Vol 27 (21) ◽  
pp. 1250117 ◽  
Author(s):  
FAYYAZUDDIN

A model for electroweak unification of quarks and leptons, in a gauge group SUC(3) × SU(4) × UX(1) is constructed. The model requires, three generations of quarks and leptons which are replicas (mirror) of the standard quarks and leptons. The gauge group SU(4) × UX(1) is broken in such a way so as to reproduce standard model and to generate heavy masses for the vector bosons [Formula: see text], the leptoquarks and mirror fermions. It is shown lower limit on mass scale of mirror fermions is [Formula: see text], E- being the lightest mirror fermion coupled to Z boson. As the universe expands, the heavy matter is decoupled at an early stage of expansion and may be a source of dark matter. Leptoquarks in the model connect the standard model and mirror fermions. Baryon genesis in our universe implies antibaryon genesis in mirror universe.


2005 ◽  
Vol 20 (17n18) ◽  
pp. 1315-1326 ◽  
Author(s):  
PIERRE MARTINETTI

We give a brief account of the description of the standard model in noncommutative geometry as well as the thermal time hypothesis, questioning their relevance for quantum gravity.


1988 ◽  
Vol 110 (4) ◽  
pp. 628-631 ◽  
Author(s):  
D. W. Glander ◽  
E. J. Bissett

It was suggested in [1] that solutions of the line contact problem of elastohydrodynamic lubrication (EHL) are unstable in a certain parameter regime, and that both stable and unstable solutions can coexist in another regime. The author also suggested that these regimes limit the applicability of the standard model equations. In this work, the present authors repeat this calculation using the highly accurate solutions described in our previous work [3]. In all cases we have considered, we find no evidence of instability or multiplicity of solutions. We conclude that the existence of regions of instability or multiplicity were based on numerical artifacts and that considerations of stability or multiplicity do not limit the applicability of the standard model equations of EHL.


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