scholarly journals THE MASS SPECTRA, HIERARCHY AND COSMOLOGY OF B-L MSSM HETEROTIC COMPACTIFICATIONS

2011 ◽  
Vol 26 (09) ◽  
pp. 1569-1627 ◽  
Author(s):  
MICHAEL AMBROSO ◽  
BURT A. OVRUT
Keyword(s):  
Renormalization Group ◽  
Gauge Symmetry ◽  
Parameter Space ◽  
Group Analysis ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Baryon Number ◽  
Initial Parameter ◽  
Renormalization Group Analysis ◽  
Expectation Value

The matter spectrum of the MSSM, including three right-handed neutrino supermultiplets and one pair of Higgs–Higgs conjugate superfields, can be obtained by compactifying the E8 ×E8 heterotic string and M-theory on Calabi–Yau manifolds with specific SU(4) vector bundles. These theories have the standard model gauge group augmented by an additional gauged U(1)B-L. Their minimal content requires that the B-L gauge symmetry be spontaneously broken by a vacuum expectation value of at least one right-handed sneutrino. In previous papers, we presented the results of a quasianalytic renormalization group analysis showing that B-L gauge symmetry is indeed radiatively broken with an appropriate B-L/electroweak hierarchy. In this paper, we extend these results by (1) enlarging the initial parameter space and (2) explicitly calculating the renormalization group equations numerically. The regions of the initial parameter space leading to realistic vacua are presented and the B-L/electroweak hierarchy computed over these regimes. At representative points, the mass spectrum for all sparticles and Higgs fields is calculated and shown to be consistent with present experimental bounds. Some fundamental phenomenological signatures of a nonzero right-handed sneutrino expectation value are discussed, particularly the cosmology and proton lifetime arising from induced lepton and baryon number violating interactions.

scholarly journals THE B – L/ELECTROWEAK HIERARCHY IN SMOOTH HETEROTIC COMPACTIFICATIONS

2010 ◽  
Vol 25 (13) ◽  
pp. 2631-2677 ◽  
Author(s):  
MICHAEL AMBROSO ◽  
BURT A. OVRUT
Keyword(s):  
Gauge Symmetry ◽  
Particle Physics ◽  
Vector Bundles ◽  
Group Analysis ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Supersymmetric Particle ◽  
Renormalization Group Analysis ◽  
Standard Models ◽  
M Theory

E8 × E8 heterotic string and M-theory, when appropriately compactified, can give rise to realistic, N = 1 supersymmetric particle physics. In particular, the exact matter spectrum of the MSSM, including three right-handed neutrino supermultiplets, one per family, and one pair of Higgs–Higgs conjugate superfields is obtained by compactifying on Calabi–Yau manifolds admitting specific SU(4) vector bundles. These "heterotic standard models" have the SU (3)C × SU (2)L × U (1)Y gauge group of the standard model augmented by an additional gauged U (1)B – L. Their minimal content requires that the B – L gauge symmetry be spontaneously broken by a vacuum expectation value of at least one right-handed sneutrino. In a previous paper, we presented the results of a renormalization group analysis showing that B – L gauge symmetry is indeed radiatively broken with a B – L/electroweak hierarchy of [Formula: see text] to [Formula: see text]. In this paper, we present the details of that analysis, extending the results to include higher order terms in tan β-1 and the explicit spectrum of all squarks and sleptons.

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 THE RENORMALIZATION GROUP IMPROVED EFFECTIVE POTENTIAL IN MASSLESS MODELS

2005 ◽  
Vol 20 (29) ◽  
pp. 2215-2226 ◽  
Author(s):  
F. T. BRANDT ◽  
F. A. CHISHTIE ◽  
D. G. C. MCKEON
Keyword(s):  
Renormalization Group ◽  
Effective Potential ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Background Field ◽  
Massless Scalar ◽  
Expectation Value

The effective potential V is considered in massless [Formula: see text] theory. The expansion of V in powers of the coupling λ and of the logarithm of the background field ϕ is reorganized in two ways; first as a series in λ alone, then as a series in ln ϕ alone. By applying the renormalization group (RG) equation to V, these expansions can be summed. Using the condition V′(v)=0 (where v is the vacuum expectation value of ϕ) in conjunction with the expansion of V in powers of ln ϕ fixes V provided v≠0. In this case, the dependence of V on ϕ drops out and V is not analytic in λ. Massless scalar electrodynamics is considered using the same approach.

scholarly journals Nucleon and dinucleon decays to leptonic final states in a left-right symmetric model with large extra dimensions

2021 ◽  
Vol 81 (2) ◽  
Author(s):  
Sudhakantha Girmohanta
Keyword(s):  
Extra Dimensions ◽  
Large Extra Dimensions ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Baryon Number ◽  
Symmetric Model ◽  
Final States ◽  
Expectation Value ◽  
Decay Modes ◽  
Higgs Vacuum

AbstractWe consider baryon-number-violating nucleon and dinucleon decays to leptonic final states in the context of a left-right symmetric (LRS) model with large extra dimensions. Specifically, we study (a) nucleon to trilepton decays with $$\varDelta B=-1$$ Δ B = - 1 and $$\varDelta L=-3$$ Δ L = - 3 , and (b) dinucleon to dilepton decays with $$\varDelta B=-2$$ Δ B = - 2 and $$\varDelta L=-2$$ Δ L = - 2 . In the LRS model, $$B-L$$ B - L is gauged and is spontaneously broken by a Higgs vacuum expectation value $$v_R$$ v R , which characterizes the scale at which processes violating $$B-L$$ B - L occur. We show that together with the lower bound on $$v_R$$ v R from experimental limits on n-$${\bar{n}}$$ n ¯ oscillations, constraints from searches for other nucleon decay modes imply sufficient suppression of these nucleon to trilepton and dinucleon to dilepton decay modes in this model to agree with experimental bounds.

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 Field Theoretical Approach for Signal Detection in Nearly Continuous Positive Spectra II: Tensorial Data

Entropy ◽  
2021 ◽  
Vol 23 (7) ◽  
pp. 795
Author(s):  
Vincent Lahoche ◽  
Mohamed Ouerfelli ◽  
Dine Ousmane Samary ◽  
Mohamed Tamaazousti
Keyword(s):  
Principal Component Analysis ◽  
Renormalization Group ◽  
Signal Detection ◽  
Detection Threshold ◽  
Principal Component ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Component Analysis ◽  
Slight Generalization ◽  
Nearly Continuous

The tensorial principal component analysis is a generalization of ordinary principal component analysis focusing on data which are suitably described by tensors rather than matrices. This paper aims at giving the nonperturbative renormalization group formalism, based on a slight generalization of the covariance matrix, to investigate signal detection for the difficult issue of nearly continuous spectra. Renormalization group allows constructing an effective description keeping only relevant features in the low “energy” (i.e., large eigenvalues) limit and thus providing universal descriptions allowing to associate the presence of the signal with objectives and computable quantities. Among them, in this paper, we focus on the vacuum expectation value. We exhibit experimental evidence in favor of a connection between symmetry breaking and the existence of an intrinsic detection threshold, in agreement with our conclusions for matrices, providing a new step in the direction of a universal statement.

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