scholarly journals A U(3)C × U(3)L × U(3)R GAUGE SYMMETRY FROM INTERSECTING D-BRANES

2008 ◽  
Vol 23 (13) ◽  
pp. 2055-2066 ◽  
Author(s):  
G. K. LEONTARIS
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Global Symmetries ◽  
Low Energy ◽  
Effective Model ◽  
End Points ◽  
The Standard Model

A three-family nonsupersymmetric model with U(3)3 gauge symmetry is analyzed in the context of intersecting D-branes. This is equivalent to the "trinification" model extended by three U(1) factors which survive as global symmetries in the low energy effective model. The Standard Model fermions are accommodated in the three possible bifundamental multiplets represented by strings with end points attached on different brane-stacks of this particular setup. Further, a natural quark–lepton hierarchy is realized due to the existence of the additional Abelian symmetries.

scholarly journals Electroweak-like baryogenesis with new chiral matter

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Kohei Fujikura ◽  
Keisuke Harigaya ◽  
Yuichiro Nakai ◽  
Ruoquan Wang
Keyword(s):  
Phase Transition ◽  
Gauge Symmetry ◽  
Cp Violation ◽  
Standard Model ◽  
Dipole Moments ◽  
Dark Matter Candidate ◽  
Lepton Asymmetry ◽  
First Order ◽  
The Standard Model ◽  
Concrete Realization

Abstract We propose a framework where a phase transition associated with a gauge symmetry breaking that occurs (not far) above the electroweak scale sets a stage for baryogenesis similar to the electroweak baryogenesis in the Standard Model. A concrete realization utilizes the breaking of SU(2)R× U(1)X→ U(1)Y. New chiral fermions charged under the extended gauge symmetry have nonzero lepton numbers, which makes the B − L symmetry anomalous. The new lepton sector contains a large flavor-dependent CP violation, similar to the Cabibbo-Kobayashi-Maskawa phase, without inducing sizable electric dipole moments of the Standard Model particles. A bubble wall dynamics associated with the first-order phase transition and SU(2)R sphaleron processes generate a lepton asymmetry, which is transferred into a baryon asymmetry via the ordinary electroweak sphaleron process. Unlike the Standard Model electroweak baryogenesis, the new phase transition can be of the strong first order and the new CP violation is not significantly suppressed by Yukawa couplings, so that the observed asymmetry can be produced. The model can be probed by collider searches for new particles and the observation of gravitational waves. One of the new leptons becomes a dark matter candidate. The model can be also embedded into a left-right symmetric theory to solve the strong CP problem.

scholarly journals Flavour Anomalies in a U(1) SUSY Extension of the SM

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva
Keyword(s):  
Standard Model ◽  
Parameter Space ◽  
Gauge Boson ◽  
New Physics ◽  
Low Energy ◽  
Effective Theory ◽  
The Standard Model ◽  
Meson Mixing ◽  
Additional Anomaly ◽  
Lepton Flavour

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.

SCALE GAUGE SYMMETRY AND THE STANDARD MODEL

1990 ◽  
Vol 05 (22) ◽  
pp. 4225-4240 ◽  
Author(s):  
J. SOLÀ
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Cosmological Constant ◽  
Minimal Model ◽  
Harmonic Map ◽  
Strong Interactions ◽  
Cosmological Constant Problem ◽  
The Standard Model ◽  
Conformal Gauge ◽  
Scalar Sector

We speculate on a version of the "standard" model of the electroweak and strong interactions coupled to gravity and equipped with a spontaneously broken, anomalous, conformal gauge symmetry. The scalar sector is virtually absent in the minimal model but in the general case it shows up in the form of a nonlinear harmonic map Lagrangian. A Euclidean approach to the cosmological constant problem is also addressed in this framework.

scholarly journals Stringy dyonic solutions and clifford structures

2019 ◽  
Vol 16 (09) ◽  
pp. 1950138
Author(s):  
A. Belfakir ◽  
A. belhaj ◽  
Y. El Maadi ◽  
S. E. Ennadifi ◽  
Y. Hassouni ◽  
...  
Keyword(s):  
Black Hole ◽  
Gauge Symmetry ◽  
Standard Model ◽  
Clifford Algebras ◽  
Magnetic Monopole ◽  
Toroidal Compactifications ◽  
The Standard Model ◽  
Arbitrary Dimensions ◽  
Electrically Charged ◽  
Clifford Structures

Using the toroidal compactification of string theory on [Formula: see text]-dimensional tori, [Formula: see text], we investigate dyonic objects in arbitrary dimensions. First, we present a class of dyonic black solutions formed by two different D-branes using a correspondence between toroidal cycles and objects possessing both magnetic and electric charges, belonging to [Formula: see text] dyonic gauge symmetry. This symmetry could be associated with electrically charged magnetic monopole solutions in stringy model buildings of the standard model (SM) extensions. Then, we consider in some detail such black hole classes obtained from even-dimensional toroidal compactifications, and we find that they are linked to [Formula: see text] Clifford algebras using the vee product. It is believed that this analysis could be extended to dyonic objects which can be obtained from local Calabi–Yau manifold compactifications.

scholarly journals Rb, Rc and New Physics: An Updated Model Independent Analysis

1997 ◽  
Vol 12 (04) ◽  
pp. 723-742 ◽  
Author(s):  
P. Bamert
Keyword(s):  
Standard Model ◽  
Neutral Current ◽  
New Physics ◽  
Low Energy ◽  
Coupling Constant ◽  
A Value ◽  
Independent Analysis ◽  
The Standard Model ◽  
Necessary And Sufficient ◽  
Do So

We analyze LEP and SLC data from the 1995 Summer Conferences as well as from low energy neutral current experiments for signals of new physics. The reasons for doing this are twofold: first to explain the deviations from the Standard Model observed in Rb and Rc and second to constrain nonstandard contributions to couplings of the Z0 boson to all fermions and to the oblique parameters. We do so by comparing the data with the Standard Model as well as with a number of test hypotheses concerning the nature of the new physics. These include nonstandard [Formula: see text]-, [Formula: see text]- and [Formula: see text]-couplings as well as the couplings of the Z0 to fermions of the entire first, second and third generations and universal corrections to all up- and down-type quark couplings (as can arise see for example in Z' mixing models). We find that nonstandard [Formula: see text] couplings are both necessary and sufficient to explain the data and in particular the Rb anomaly. It is not possible to explain Rb, Rc and a value of the strong coupling constant consistent with low energy determinations invoking only nonstandard [Formula: see text]- and [Formula: see text]-couplings. To do so one has to have also new physics contributions to the [Formula: see text] or universal corrections to all [Formula: see text] couplings.

TECHNIDILATON OR HIGGS?

1993 ◽  
Vol 08 (03) ◽  
pp. 275-283 ◽  
Author(s):  
EDI HALYO
Keyword(s):  
Standard Model ◽  
Energy Momentum Tensor ◽  
Momentum Tensor ◽  
Higgs Bosons ◽  
Low Energy ◽  
Gauge Bosons ◽  
Effective Lagrangian ◽  
The Standard Model

Interactions of the technidilaton with fermions and gauge bosons are obtained by constructing a low energy effective Lagrangian and using the fact that the technidilaton couples to the trace of the energy-momentum tensor Θµµ. Technidilaton’s interactions are compared with those of the Higgs bosons of the Standard Model with one or two scalar doublets.

scholarly journals Search for Charged Lepton Flavour Violation at CMS

2018 ◽  
Vol 182 ◽  
pp. 02090
Author(s):  
Swagata Mukherjee
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Particle Physics ◽  
Charged Lepton ◽  
New Physics ◽  
Lepton Sector ◽  
Lepton Flavour Violation ◽  
The Standard Model ◽  
Flavour Violation ◽  
Lepton Flavour

Lepton flavour is a conserved quantity in the standard model of particle physics, but it does not follow from an underlying gauge symmetry. After the discovery of neutrino oscillation, it has been established that lepton flavour is not conserved in the neutral sector. Thus the lepton sector is an excellent place to look for New Physics, and in this perspective the Charged Lepton Flavour Violation is interesting. Various extensions of the standard model predict lepton flavour violating decays that can be observed at LHC. This report summarises several searches for lepton flavour violation with data collected by the CMS detector.

scholarly journals η′K PUZZLE OF B MESON DECAYS AND NEW PHYSICS EFFECTS IN THE TC2 MODEL

2001 ◽  
Vol 16 (07) ◽  
pp. 441-455 ◽  
Author(s):  
ZHENJUN XIAO ◽  
WENJUN LI ◽  
GONGRU LU ◽  
LIBO GUO
Keyword(s):  
Standard Model ◽  
B Meson ◽  
New Physics ◽  
Decay Rates ◽  
Low Energy ◽  
Effective Hamiltonian ◽  
B Meson Decays ◽  
The Standard Model ◽  
Model Predictions ◽  
Input Parameters

Using the low energy effective Hamiltonian with the generalized factorization, we calculate the new physics contributions to B→π+π-, Kπ and Kη′ in the topcolor-assisted-technicolor (TC2) model, and compare the results with the available data. By using [Formula: see text] preferred by the CLEO data of B→π+π-decay, we find that the new physics enhancements to B→ Kη′ decays are significant in size, ~ 50% with respect to the standard model predictions, insensitive to the variations of input parameters and hence provide a simple and plausible new physics interpretation for the observed unexpectedly large B→ Kη′ decay rates.

scholarly journals A SUPERSYMMETRIC MODEL WITH THE GAUGE SYMMETRY SU(3)1 × SU(2)1 × U(1)1 × SU(3)2 × SU(2)2 × U(1)2

2003 ◽  
Vol 18 (14) ◽  
pp. 967-975 ◽  
Author(s):  
J. G. KÖRNER ◽  
CHUN LIU
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Symmetry Breaking ◽  
Supersymmetry Breaking ◽  
Simple Form ◽  
Electroweak Symmetry Breaking ◽  
Supersymmetric Model ◽  
Electroweak Symmetry ◽  
Gauge Groups ◽  
The Standard Model

A supersymmetric model with two copies of the Standard Model gauge groups is constructed in the gauge mediated supersymmetry breaking scenario. The supersymmetry breaking messengers are in a simple form. The Standard Model is obtained after first step gauge symmetry breaking. In the case of one copy of the gauge interactions being strong, a scenario of electroweak symmetry breaking is discussed, and the gauginos are generally predicted to be heavier than the sfermions.

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