scholarly journals Moderately suppressed dimension-five proton decay in a flipped SU(5) model

2022 ◽  
Vol 2022 (1) ◽  
Author(s):  
Naoyuki Haba ◽  
Toshifumi Yamada
Keyword(s):  
Mass Term ◽  
Proton Decay ◽  
Model Structure ◽  
Ckm Matrix ◽  
Decay Modes ◽  
Yukawa Couplings ◽  
Higher Dimensional ◽  
Gut Scale ◽  
Higgs Fields ◽  
Current Bound

Abstract We study colored Higgsino-mediated proton decay (dimension-five proton decay) in a model based on the flipped SU(5) GUT. In the model, the GUT-breaking 10, $$ \overline{\mathbf{10}} $$ 10 ¯ fields have a GUT-scale mass term and gain VEVs through higher-dimensional operators, which induces an effective mass term between the color triplets in the 5, $$ \overline{\mathbf{5}} $$ 5 ¯ Higgs fields that is not much smaller than the GUT scale. This model structure gives rise to observable dimension-five proton decay, and at the same time achieves moderate suppression on dimension-five proton decay that softens the tension with the current bound on Γ(p → K+$$ \overline{\nu} $$ ν ¯ ). We investigate the flavor dependence of the Wilson coefficients of the operators relevant to dimension-five proton decay, by relating them with diagonalized Yukawa couplings and CKM matrix components in MSSM, utilizing the fact that the GUT Yukawa couplings are in one-to-one correspondence with the MSSM Yukawa couplings in flipped models. Then we numerically evaluate the Wilson coefficients, and predict the distributions of the ratios of the partial widths of various proton decay modes.

scholarly journals Proton decay in supersymmetric SU(4)c × SU(2)L × SU(2)R

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
George Lazarides ◽  
Mansoor Ur Rehman ◽  
Qaisar Shafi
Keyword(s):  
Essential Role ◽  
Baryon Number ◽  
Proton Decay ◽  
Unified Theory ◽  
Grand Unified Theory ◽  
Decay Modes ◽  
Proposed Model ◽  
Hybrid Inflation ◽  
Gut Scale ◽  
Chiral Superfields

Abstract We discuss proton decay in a recently proposed model of supersymmetric hybrid inflation based on the gauge symmetry SU(4)c× SU(2)L× SU(2)R. A U(1) R symmetry plays an essential role in realizing inflation as well as in eliminating some undesirable baryon number violating operators. Proton decay is primarily mediated by a variety of color triplets from chiral superfields, and it lies in the observable range for a range of intermediate scale masses for the triplets. The decay modes include p → e+(μ+) + π0, $$ p\to \overline{\nu}+{\pi}^{+} $$ p → ν ¯ + π + , p → K0 + e+(μ+), and $$ p\to {K}^{+}+\overline{\nu} $$ p → K + + ν ¯ , with a lifetime estimate of order 1034–1036 yrs and accessible at Hyper-Kamiokande and future upgrades. The unification at the Grand Unified Theory (GUT) scale MGUT (∼ 1016 GeV) of the Minimal Supersymmetric Standard Model (MSSM) gauge couplings is briefly discussed.

scholarly journals R-symmetric flipped SU(5)

2020 ◽  
Vol 2020 (11) ◽  
Author(s):  
Koichi Hamaguchi ◽  
Shihwen Hor ◽  
Natsumi Nagata
Keyword(s):  
Scale Up ◽  
Higgs Field ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Large Mass ◽  
Proton Decay ◽  
Decay Modes ◽  
Splitting Problem ◽  
The Masses ◽  
Higgs Fields

Abstract We construct a supersymmetric flipped SU(5) grand unified model that possesses an R symmetry. This R symmetry forbids dangerous non-renormalizable operators suppressed by a cut-off scale up to sufficiently large mass dimensions so that the SU(5)-breaking Higgs field develops a vacuum expectation value of the order of the unification scale along the F- and D-flat directions, with the help of the supersymmetry-breaking effect. The mass terms of the Higgs fields are also forbidden by the R symmetry, with which the doublet-triplet splitting problem is solved with the missing partner mechanism. The masses of right-handed neutrinos are generated by non-renormalizable operators, which then yield a light neutrino mass spectrum and mixing through the seesaw mechanism that are consistent with neutrino oscillation data. This model predicts one of the color-triplet Higgs multiplets to lie at an intermediate scale, and its mass is found to be constrained by proton decay experiments to be ≳ 5 × 1011 GeV. If it is ≲ 1012 GeV, future proton decay experiments at Hyper-Kamiokande can test our model in the p → π0μ+ and p → K0μ+ decay modes, in contrast to ordinary grand unified models where p → π0e+ or p → $$ {K}^{+}\overline{\nu} $$ K + ν ¯ is the dominant decay mode. This characteristic prediction for the proton decay branches enables us to distinguish our model from other scenarios.

scholarly journals Positivity bounds on Minimal Flavor Violation

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Quentin Bonnefoy ◽  
Emanuele Gendy ◽  
Christophe Grojean
Keyword(s):  
Standard Model ◽  
Effective Field ◽  
Minimal Flavor Violation ◽  
Ckm Matrix ◽  
Yukawa Couplings ◽  
Flavor Violation ◽  
Higher Dimensional ◽  
The Standard Model ◽  
The One ◽  
Yukawa Sector

Abstract From general analyticity and unitarity requirements on the UV theory, positivity bounds on the Wilson coefficients of the dimension-8 operators composed of 4 fermions and two derivatives appearing in the Standard Model Effective Field Theory have been derived recently. We explore the fate of these bounds in the context of models endowed with a Minimal Flavor Violation (MFV) structure, models in which the flavor structure of higher dimensional operators is inherited from the one already contained in the Yukawa sector of the Standard Model Lagrangian. Our goal is to check whether the general positivity bounds translate onto bounds on the Yukawa coefficients and/or on elements of the CKM matrix. MFV fixes the coefficients of dimension-8 operators up to some multiplicative flavor-blind factors and we find that, in the most generic setup, the freedom left by those unspecified coefficients is enough as not to constrain the parameters of the renormalizable Yukawa sector. On the contrary, the latter shape the allowed region for the former. Requiring said overall coefficients to take natural $$ \mathcal{O}(1) $$ O 1 values could give rise to bounds on the Yukawa couplings. Remarkably, at leading order in an expansion in powers of the Yukawa matrices, no bounds on the CKM entries can be retrieved.

scholarly journals Corrections to Yukawa couplings from higher dimensional operators in a natural SUSY SO(10) and HL-LHC implications

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Amin Aboubrahim ◽  
Pran Nath ◽  
Raza M. Syed
Keyword(s):  
Gauge Group ◽  
Hadron Collider ◽  
High Energy ◽  
Spontaneous Breaking ◽  
Electroweak Symmetry ◽  
Yukawa Couplings ◽  
A Value ◽  
Higher Dimensional ◽  
Higgs Fields ◽  
Natural Way

Abstract We consider a class of unified models based on the gauge group SO(10) which with appropriate choice of Higgs representations generate in a natural way a pair of light Higgs doublets needed to accomplish electroweak symmetry breaking. In this class of models higher dimensional operators of the form matter-matter-Higgs-Higgs in the superpotential after spontaneous breaking of the GUT symmetry generate contributions to Yukawa couplings which are comparable to the ones from cubic interactions. Specifically we consider an SO(10) model with a sector consisting of 126 + $$ \overline{126} $$ 126 ¯ + 210 of heavy Higgs which breaks the GUT symmetry down to the standard model gauge group and a sector consisting of 2 × 10 + 120 of light Higgs fields. In this model we compute the corrections from the quartic interactions to the Yukawa couplings for the top and the bottom quarks and for the tau lepton. It is then shown that inclusion of these corrections to the GUT scale Yukawas allows for consistency of the top, bottom and tau masses with experiment for low tan β with a value as low as tan β of 5–10. We compute the sparticle spectrum for a set of benchmarks and find that satisfaction of the relic density is achieved via a compressed spectrum and coannihilation and three sets of coannihilations appear: chargino-neutralino, stop-neutralino and stau-neutralino. We investigate the chargino-neutralino coannihilation in detail for the possibility of observation of the light chargino at the high luminosity LHC (HL-LHC) and at the high energy LHC (HE-LHC) which is a possible future 27 TeV hadron collider. It is shown that all benchmark models but one can be discovered at HL-LHC and all would be discoverable at HE-LHC. The ones discoverable at both machines require a much shorter time scale and a lower integrated luminosity at HE-LHC.

scholarly journals SO(10) UNIFICATION IN NONCOMMUTATIVE GEOMETRY REVISITED

1999 ◽  
Vol 14 (04) ◽  
pp. 559-588 ◽  
Author(s):  
RAIMAR WULKENHAAR
Keyword(s):  
Standard Model ◽  
Noncommutative Geometry ◽  
Mass Term ◽  
Tree Level ◽  
Model Structure ◽  
Fermion Masses ◽  
The Standard Model ◽  
The Right ◽  
Higgs Fields ◽  
Algebraic Formulation

We investigate the SO(10) unification model in a Lie-algebraic formulation of noncommutative geometry. The SO(10) symmetry is broken by a 45-Higgs and the Majorana mass term for the right neutrinos (126-Higgs) to the standard model structure group. We study the case where the fermion masses are as general as possible, which leads to two 10-multiplets, four 120-multiplets and two additional 126-multiplets of Higgs fields. This Higgs structure differs considerably from the two Higgs multiplets 16 ⊗ 16* and 16c ⊗ 16* used by Chamseddine and Fröhlich. We find the usual tree level predictions of noncommutative geometry: [Formula: see text], [Formula: see text] and g2=g3 as well as mH≤ mt.

scholarly journals Generalized vanishing theorems for Yukawa couplings in heterotic compactifications

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Lara B. Anderson ◽  
James Gray ◽  
Magdalena Larfors ◽  
Matthew Magill ◽  
Robin Schneider
Keyword(s):  
Vector Bundles ◽  
Geometric Approach ◽  
Low Energy ◽  
Geometric Features ◽  
Vanishing Theorems ◽  
Vanishing Theorem ◽  
Alternative Derivation ◽  
Yukawa Couplings ◽  
Geometric Methods ◽  
Higher Dimensional

Abstract Heterotic compactifications on Calabi-Yau threefolds frequently exhibit textures of vanishing Yukawa couplings in their low energy description. The vanishing of these couplings is often not enforced by any obvious symmetry and appears to be topological in nature. Recent results used differential geometric methods to explain the origin of some of this structure [1, 2]. A vanishing theorem was given which showed that the effect could be attributed, in part, to the embedding of the Calabi-Yau manifolds of interest inside higher dimensional ambient spaces, if the gauge bundles involved descended from vector bundles on those larger manifolds. In this paper, we utilize an algebro-geometric approach to provide an alternative derivation of some of these results, and are thus able to generalize them to a much wider arena than has been considered before. For example, we consider cases where the vector bundles of interest do not descend from bundles on the ambient space. In such a manner we are able to highlight the ubiquity with which textures of vanishing Yukawa couplings can be expected to arise in heterotic compactifications, with multiple different constraints arising from a plethora of different geometric features associated to the gauge bundle.

scholarly journals FLAVOR SYMMETRY AND VACUUM ALIGNED MASS TEXTURES

2007 ◽  
Vol 16 (05) ◽  
pp. 1427-1436 ◽  
Author(s):  
SATORU KANEKO ◽  
HIDEYUKI SAWANAKA ◽  
TAKAYA SHINGAI ◽  
MORIMITSU TANIMOTO ◽  
KOICHI YOSHIOKA
Keyword(s):  
Scalar Potential ◽  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Flavor Symmetry ◽  
Yukawa Couplings ◽  
Flavor Changing ◽  
Symmetry Approach ◽  
Mass Matrices ◽  
Vanishing Elements ◽  
Higgs Fields

A texture-zeros is an approach to reduce the number of free parameters in Yukawa couplings and it is one of the most attractive ones. In our paper, we discuss the origin of zero-structure in texture-zeros by S3 flavor symmetry approach. Some of electroweak doublet Higgs fields have vanishing vacuum expectation value (VEV) which leads to vanishing elements in quark and lepton mass matrices. Then, the structure of supersymmetric scalar potential is analyzed and Higgs fields have non-trivial S3 charges. As a prediction of our paper, a lower bound of a MNS matrix element, Ue3 ≥ 0.04, is obtained. The suppression of flavor-changing neutral currents (FCNC) mediated by the Higgs fields is discussed and lower bounds of the Higgs masses are derived.

scholarly journals Enhanced $\Gamma(p\to K^0\mu^+)/\Gamma(p\to K^+\bar{\nu}_\mu)$ as a signature of minimal renormalizable SUSY SO (10) GUT

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Naoyuki Haba ◽  
Yukihiro Mimura ◽  
Toshifumi Yamada
Keyword(s):  
Partial Width ◽  
Width Ratio ◽  
Detailed Knowledge ◽  
Main Body ◽  
Grand Unified Theory ◽  
Plausible Assumption ◽  
Decay Modes ◽  
Yukawa Couplings ◽  
2Nd Generation ◽  
Left Handed

Abstract The ratio of the partial widths of some dimension-5 proton decay modes can be predicted without detailed knowledge of supersymmetric (SUSY) particle masses, and this allows us to experimentally test various SUSY grand unified theory (GUT) models without discovering SUSY particles. In this paper, we study the ratio of the partial widths of the $p\to K^0\mu^+$ and $p\to K^+\bar{\nu}_\mu$ decays in the minimal renormalizable SUSY $SO(10)$ GUT, under only a plausible assumption that the 1st- and 2nd-generation left-handed squarks are mass-degenerate. In the model, we expect that the Wilson coefficients of dimension-5 operators responsible for these modes are on the same order and that the ratio of $p\to K^0\mu^+$ and $p\to K^+\bar{\nu}_\mu$ partial widths is $O(0.1)$. Hence, we may be able to detect both $p\to K^0\mu^+$ and $p\to K^+\bar{\nu}_\mu$ decays at Hyper-Kamiokande, thereby gaining a hint for the minimal renormalizable SUSY $SO(10)$ GUT. Moreover, since this partial width ratio is quite suppressed in the minimal $SU(5)$ GUT, it allows us to distinguish the minimal renormalizable SUSY $SO(10)$ GUT from the minimal $SU(5)$ GUT. In the main body of the paper, we perform a fitting of the quark and lepton masses and flavor mixings with the Yukawa couplings of the minimal renormalizable $SO(10)$ GUT, and derive a concrete prediction for the partial width ratio based on the fitting results. We find that the partial width ratio generally varies in the range $0.05$–$0.6$, confirming the above expectation.

scholarly journals Pentaquarks and possible anomalies at LHCb

2016 ◽  
Vol 31 (20n21) ◽  
pp. 1630032
Author(s):  
G. Lafferty
Keyword(s):  
Matrix Element ◽  
Standard Model ◽  
Meson Decay ◽  
Flavour Changing Neutral Currents ◽  
Neutral Currents ◽  
Ckm Matrix ◽  
Lhcb Experiment ◽  
Decay Modes ◽  
Model Predictions ◽  
Lepton Flavour

With the LHC Run 1 data, the LHCb experiment discovered two pentaquark states and has evidence for a number of possible anomalies in the flavour sector. The possible anomalies include indications of violations of lepton flavour universality, deviations from Standard Model predictions in several [Formula: see text]-meson decay modes that are mediated by flavour-changing neutral currents, and further evidence for a discrepancy between inclusive and exclusive measurements of the CKM matrix element [Formula: see text].

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