SU Symmetry Research Articles

Constraint on the warped space from B̄ → Xsγ

We analyze the theoretical prediction on the branching ratio of B̄ → Xsγ to order Λ2EW/Λ2KK in extension of the standard model with a warped extra dimension and the custodial symmetry SU(3)c×SU(2)L×SU(2)R×U(1)X×PLR, where ΛKK denotes the energy scale of low-lying Kaluze-Klein excitations and ΛEW denotes the electroweak energy scale. Contributions from the infinite series of Kaluze-Klein excitations are summed over through the residue theorem. The numerical result indicates that the present experimental data constrain the parameter space of the concerned model strongly.

Internal Coordinates, SU3 Symmetry and Charge of Elementary Particles

Internal Coordinates, SU3 Symmetry and Charge of Elementary Particles

Geno-Bragg's law and 10*x10 representation of SU(3) symmetry for quasicrystal structures

The synthesis of quasicrystals and observation of their unexpected 10-fold symmetric diffraction pattern by D. Shechtman and co-workers 1982--1984 provide a natural bridge for bringing solid state condensed matter physics within the purview of Santilli's 1967--2006 Lie-admissible generalization of quantum mechanics QM under the name hadronic mechanics HM via our recent non-unitary scattering theory of HM for deep-inelastic e^--p and e^+-e^-scattering processes. This is achieved in this paper by a re-formulation and elaboration of Bragg's law of diffraction for quasicrystals under the title Geno-Bragg's law which permits identification of the deformed quasicrystalline state with 10^*x10 representation of SU3 symmetry. Essentially, because only 1-,2-,3-,4-and 6-fold but not 5-fold point symmetry of perfectly periodic crystal lattice are allowed in 3-dimensional 3D real or reciprocal lattice space, a non-unitary deformation of the allowed cubic 4-fold and hexagonal 6-fold symmetry axes into a common diffraction square-hexagon geno-plane having 10-fold point symmetry is achievable as envisaged in HM. As a result, the current icosahedron approximant structure is replaced by cube-hexagon genospace structure that permits determination of atomic distribution in quasicrystals as holographic periodic structure. Further elaboration of Geno-Bragg's law to high energy relativistic deep-inelastic scattering processes described by current-current interaction models of neutron synthesis/decay is applied to the determination of the structure of the neutron and the implications for geno-renormalization of mass and the ratios of the masses of the elementary particles are discussed.

Odd parity bottom-flavored baryon resonances

The LHCb Collaboration has recently observed two narrow baryon resonances with beauty. Their masses and decay modes look consistent with the quark model orbitally excited states ${\ensuremath{\Lambda}}_{b}(5912)$ and ${\ensuremath{\Lambda}}_{b}^{*}(5920)$, with quantum numbers ${J}^{P}=1/{2}^{\ensuremath{-}}$ and $3/{2}^{\ensuremath{-}}$, respectively. We predict the existence of these states within a unitarized meson-baryon coupled-channel dynamical model, which implements heavy-quark spin symmetry. Masses, quantum numbers and couplings of these resonances to the different meson-baryon channels are obtained. We find that the resonances ${\ensuremath{\Lambda}}_{b}^{0}(5912)$ and ${\ensuremath{\Lambda}}_{b}^{0}(5920)$ are heavy-quark spin symmetry partners, which naturally explains their approximate mass degeneracy. Corresponding bottom-strange baryon resonances are predicted at ${\ensuremath{\Xi}}_{b}(6035.4)$ (${J}^{P}=\frac{1}{2}\genfrac{}{}{0}{}{{}^{\ensuremath{-}}}{}$) and ${\ensuremath{\Xi}}_{b}(6043.3)$ (${J}^{P}=\frac{3}{2}\genfrac{}{}{0}{}{{}^{\ensuremath{-}}}{}$). The two ${\ensuremath{\Lambda}}_{b}$ and two ${\ensuremath{\Xi}}_{b}$ resonances complete a multiplet of the combined symmetry SU(3)-flavor times heavy-quark spin.

T→cγ and t→cg in warped extra dimensions

In this work, we calculate the top quark rare decays t-cgamma and t-cg in the framework where the standard model is embedded in a warped extra dimension with the custodial symmetry SU(3)c*SU(2)L*SU(2)R*U(1)x*PLR. Adopting reasonable assumptions on the parameter space,we numerically find the branching ratios of t-cgamma exceeding 10^-6 and that of t-cg exceeding 10^-5 respectively, which can be detected in near future.

New mixing structures of chiral generations in a model with noncompact horizontal symmetry

New mixing structures between chiral generations of elementary particles at low energy are shown in a vectorlike model with a horizontal symmetry SU(1,1). In this framework the chiral model including odd number chiral generations is realized via the spontaneous symmetry breaking of the horizontal symmetry. It is shown that the Yukawa coupling matrices of chiral generations have naturally hierarchical patterns, and in some cases the overall factors of their Yukawa coupling matrices, e.g. the Yukawa coupling constants of the bottom quark and tau lepton are naturally suppressed.

An algebraic approach to QCD and superconduction

The SU3 spin connections in an Elliptic Space are found to provide the two vortices at an angle of ω = 120 degrees shown in Fig.3.Then by relating the vertices of the 24-cell,labeled by 0, ±1 ,ω , ω 2 to quarks and leptons,we can show that they all occupy elliptic spaces. In particular Fig.3 could illustrate a Cooper pair of electrons,if cold enough.Otherwise a single electron, which can inhabit either vortex core, may act as a link in a superconducting chain on a nanowire at a finite temperature.Furthermore we will find that the three quarks in a proton,neutron or strange particle are distinguished by a rotation through ω .T hus if we consider the 6 paths of fig.3 to be two sets of gluons labeled by r,b,g and r, b, r and add the possible rotations between quarks we can incorporate gluon bindings such as rb, rg and so on, which are a basis for the SU3 symmetry underlining QCD.

LHC Higgs signatures from extended electroweak gauge symmetry

We study LHC Higgs signatures from the extended electroweak gauge symmetry SU(2) x SU(2) x U(1). Under this gauge structure, we present an effective UV completion of the 3-site moose model with ideal fermion delocalization, which contains two neutral Higgs states (h, H) and three new gauge bosons (W', Z'). We study the unitarity, and reveal that the exact E^2 cancellation in the longitudinal WW scattering amplitudes is achieved by the joint role of exchanging both spin-1 new gauge bosons and spin-0 Higgs bosons. We identify the lighter Higgs state h with mass 125GeV, and derive the unitarity bound on the mass of heavier Higgs boson H. The parameter space of this model is highly predictive. We study the production and decay signals of this 125GeV Higgs boson h at the LHC. We demonstrate that the h Higgs boson can naturally have enhanced signals in the diphoton channel $gg \to h \to\gamma\gamma$, while the events rates in the reactions $gg \to h \to WW^*$ and $gg \to h \to ZZ^*$ are generally suppressed relative to the SM expectation. Searching the h Higgs boson via associated productions and vector boson fusions are also discussed for our model. We further analyze the LHC signals of the heavier Higgs boson H as a distinctive new physics discriminator from the SM. For wide mass-ranges of H, we derive constraints from the existing LHC searches, and study the discovery potential of H at the LHC(8TeV) and LHC(14TeV).

Minimal flavour violation and neutrino masses without R-parity

We study the extension of the Minimal Flavour Violation (MFV) hypothesis to the MSSM without R-parity. The novelty of our approach lies in the observation that supersymmetry enhances the global symmetry of the kinetic term and in the fact that we consider as irreducible sources of the flavour symmetry breaking all the couplings of the superpotential including the R-parity violating ones. If R-parity violation is responsible for neutrino masses, our setup can be seen as an extension of MFV to the lepton sector. We analyze two patterns based on the non-abelian flavour symmetries SU(3)^4 \otimes SU(4) and SU(3)^5. In the former case the total lepton number and the lepton flavour number are broken together, while in the latter the lepton number can be broken independently by an abelian spurion, so that visible effects and peculiar correlations can be envisaged in flavour changing charged lepton decays like \ell_i \rightarrow \ell_j \gamma.

THE THIRD TYPE OF FERMION MIXING IN THE LEPTON AND QUARK INTERACTIONS WITH LEPTOQUARKS

The low-energy manifestations of a minimal extension of the electroweak standard model based on the quark–lepton symmetry SU(4)V ⊗SU(2)L ⊗GR of the Pati–Salam-type are analyzed. Given this symmetry the third type of mixing in the interactions of the SU(4)V leptoquarks with quarks and leptons is shown to be required. An additional arbitrariness of the mixing parameters could allow, in principle, to decrease noticeably the lower bound on the vector leptoquark mass originated from the low-energy rare processes, strongly suppressed in the standard model.

A Model of Fermion Masses and Flavor Mixings with Family Symmetry SU(3) ⊗ U(1)

The family symmetry SU(3) ⊗ U(1) is proposed to solve flavor problems about fermion masses and flavor mixings. It is breaking is implemented by some flavon fields at the high-energy scale. In addition a discrete group Z2 is introduced to generate tiny neutrino masses, which is broken by a real singlet scalar field at the middle-energy scale. The low-energy effective theory is elegantly obtained after all of super-heavy fermions are integrated out and decoupling. All the fermion mass matrices are regularly characterized by four fundamental matrices and thirteen parameters. The model can perfectly fit and account for all the current experimental data about the fermion masses and flavor mixings, in particular, it finely predicts the first generation quark masses and the values of θl13 and JlCP in neutrino physics. All of the results are promising to be tested in the future experiments.

Nearest-neighbor-interactions from a minimal discrete flavor symmetry withinSU(5)grand unification

A flavour symmetry based on Z_4 is analysed in the context of SU(5) Grand Unification with the standard fermionic content plus three right-handed neutrinos. The role of Z_4 is to forbid some Yukawa couplings of up- and down-quarks to Higgs scalars such that the quark mass matrices M_u, M_d have Nearest-Neighbour-Interaction (NNI) structure, once they are generated through the electroweak symmetry breaking. It turns out in this framework that Z_4 is indeed the minimal discrete symmetry and its implementation requires the introduction of at least two Higgs quintets, which leads to a two Higgs doublet model at low energy scale. Due to the SU(5) unification, it is shown that the charged lepton mass matrix develops also NNI form. However, the effective neutrino mass matrix exhibits a non parallel pattern, in the framework of the type-I seesaw mechanism. Analysing all possible zero textures allowed by gauge-horizontal symmetry SU(5) x Z_4, it is seen that only two patterns are in agreement with the leptonic experimental data and they could be further distinguished by the light neutrino mass spectrum hierarchy. It is also demonstrated that Z_4 freezes out the possibility of proton decay through exchange of colour Higgs triplets at tree-level.

Nonstandard Neutrinos Interactions in a 331 Model with Minimum Higgs Sector

We present a detailed analysis of a class of extensions to the SM Gauge chiral symmetry <svg style="vertical-align:-3.24037pt;width:166.21124px;" id="M1" height="15.84875" version="1.1" viewBox="0 0 166.21124 15.84875" width="166.21124" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(1.25,0,0,-1.25,0,15.84875)"> <text transform="matrix(1,0,0,-1,0.498,3.729)"> <tspan style="font-size: 12.50px; " x="0" y="0">𝑆</tspan> <tspan style="font-size: 12.50px; " x="8.1270285" y="0">𝑈</tspan> <tspan style="font-size: 12.50px; " x="16.941727" y="0">(</tspan> <tspan style="font-size: 12.50px; " x="21.105267" y="0">3</tspan> <tspan style="font-size: 12.50px; " x="27.356827" y="0">)</tspan> </text> <text transform="matrix(1,0,0,-1,32.018,0.603)"> <tspan style="font-size: 8.75px; " x="0" y="0">𝐶</tspan> </text> <text transform="matrix(1,0,0,-1,41.182,3.729)"> <tspan style="font-size: 12.50px; " x="0" y="0">×</tspan> <tspan style="font-size: 12.50px; " x="10.777689" y="0">𝑆</tspan> <tspan style="font-size: 12.50px; " x="18.904716" y="0">𝑈</tspan> <tspan style="font-size: 12.50px; " x="27.719418" y="0">(</tspan> <tspan style="font-size: 12.50px; " x="31.882956" y="0">3</tspan> <tspan style="font-size: 12.50px; " x="38.134518" y="0">)</tspan> </text> <text transform="matrix(1,0,0,-1,83.483,0.603)"> <tspan style="font-size: 8.75px; " x="0" y="0">𝐿</tspan> </text> <text transform="matrix(1,0,0,-1,92.971,3.729)"> <tspan style="font-size: 12.50px; " x="0" y="0">×</tspan> <tspan style="font-size: 12.50px; " x="10.777689" y="0">𝑈</tspan> <tspan style="font-size: 12.50px; " x="19.592388" y="0">(</tspan> <tspan style="font-size: 12.50px; " x="23.755928" y="0">1</tspan> <tspan style="font-size: 12.50px; " x="30.007488" y="0">)</tspan> </text> <text transform="matrix(1,0,0,-1,127.145,0.603)"> <tspan style="font-size: 8.75px; " x="0" y="0">𝑥</tspan> </text> </g> </svg> (331 model), where the neutrino electroweak interaction with matter via charged and neutral current is modified through new gauge bosons of the model. We found the connections between the nonstandard contributions on 331 model with nonstandard interactions. Through limits of such interactions in cross-section experiments, we constrained the parameters of the model, obtaining that the new energy scale of this theory should obey <svg style="vertical-align:-0.30096pt;width:49.15625px;" id="M2" height="12.185" version="1.1" viewBox="0 0 49.15625 12.185" width="49.15625" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(1.25,0,0,-1.25,0,12.185)"> <text transform="matrix(1,0,0,-1,0.498,0.798)"> <tspan style="font-size: 12.50px; " x="0" y="0">𝑉</tspan> <tspan style="font-size: 12.50px; " x="10.652658" y="0">&gt;</tspan> <tspan style="font-size: 12.50px; " x="22.693163" y="0">1</tspan> <tspan style="font-size: 12.50px; " x="28.944723" y="0">.</tspan> <tspan style="font-size: 12.50px; " x="32.070503" y="0">3</tspan> </text> </g> </svg> TeV and the new bosons of the model must have masses greater than 610&#x2009;GeV.

Sources of FCNC in 𝑆𝑈(3)𝐶⊗𝑆𝑈(3)𝐿⊗𝑈(1)𝑋 Models

There are different models which are based on the gauge symmetry <svg style="vertical-align:-3.24037pt;width:180.66251px;" id="M2" height="14.725" version="1.1" viewBox="0 0 180.66251 14.725" width="180.66251" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(1.25,0,0,-1.25,0,14.725)"> <g transform="translate(72,-60.22)"> <text transform="matrix(1,0,0,-1,-71.95,63.5)"> <tspan style="font-size: 12.50px; " x="0" y="0">𝑆</tspan> <tspan style="font-size: 12.50px; " x="8.1269503" y="0">𝑈</tspan> <tspan style="font-size: 12.50px; " x="18.304392" y="0">(</tspan> <tspan style="font-size: 12.50px; " x="22.467892" y="0">3</tspan> <tspan style="font-size: 12.50px; " x="28.719391" y="0">)</tspan> </text> <text transform="matrix(1,0,0,-1,-39.05,60.37)"> <tspan style="font-size: 8.75px; " x="0" y="0">𝐶</tspan> </text> <text transform="matrix(1,0,0,-1,-29.21,63.5)"> <tspan style="font-size: 12.50px; " x="0" y="0">⊗</tspan> <tspan style="font-size: 12.50px; " x="13.303192" y="0">𝑆</tspan> <tspan style="font-size: 12.50px; " x="21.430141" y="0">𝑈</tspan> <tspan style="font-size: 12.50px; " x="31.620087" y="0">(</tspan> <tspan style="font-size: 12.50px; " x="35.783585" y="0">3</tspan> <tspan style="font-size: 12.50px; " x="42.035088" y="0">)</tspan> </text> <text transform="matrix(1,0,0,-1,17,60.37)"> <tspan style="font-size: 8.75px; " x="0" y="0">𝐿</tspan> </text> <text transform="matrix(1,0,0,-1,26.47,63.5)"> <tspan style="font-size: 12.50px; " x="0" y="0">⊗</tspan> <tspan style="font-size: 12.50px; " x="13.303192" y="0">𝑈</tspan> <tspan style="font-size: 12.50px; " x="23.493137" y="0">(</tspan> <tspan style="font-size: 12.50px; " x="27.656635" y="0">1</tspan> <tspan style="font-size: 12.50px; " x="33.908134" y="0">)</tspan> </text> <text transform="matrix(1,0,0,-1,64.54,60.37)"> <tspan style="font-size: 8.75px; " x="0" y="0">𝑋</tspan> </text> </g> </g> </svg> (331), and some of them include exotic particles, and others are constructed without any exotic charges assigned to the fermionic spectrum. Each model build-up on 331 symmetry has its own interesting properties according to the representations of the gauge group used for the fermionic spectrum, that is, the main reason to explore and identify the possible sources of flavor changing neutral currents and lepton flavor violation at tree level.

Flavor changing neutral currents,CPviolation, and implications for some rare decays in aSU(4)L⊗U(1)Xextension of the standard model

Extensions of the standard model (SM) with gauge symmetry SU(3)_c X SU(4)_L X U(1)_X (3-4-1 extensions) where anomaly cancellation takes place between the fermion families (three-family models) predict the existence of two new heavy neutral gauge bosons which transmit flavor changing neutral currents (FCNC) at tree-level. In this work, in the context of a three-family 3-4-1 extension which does not contain particles with exotic electric charges, we study the constraints coming from neutral meson mixing on the parameters of the extension associated to tree level FCNC effects. Taking into account experimental measurements of observables related to K and B meson mixing and including new CP-violating phases, we study the resulting bounds for angles and phases in the mixing matrix for the down-quark sector, as well as the implications of these bounds for the modifications in the amplitudes of the clean rare decays K^+ -> \pi^+ \bar\nu \nu, K_{L} -> \pi^0 \nu \bar\nu, K_L -> \pi^0 l^+ l^- (l=e,\mu) and B_{d/s} -> \mu^+ \mu^-.

Flavor and CP invariant composite Higgs models

The flavor protection in composite Higgs models with partial compositeness is known to be insufficient. We explore the possibility to alleviate the tension with CP odd observables by assuming that flavor or CP are symmetries of the composite sector, broken by the coupling to Standard Model fields. One realization is that the composite sector has a flavor symmetry SU(3) or SU(3)_U x SU(3)_D which allows us to realize Minimal Flavor Violation. We show how to avoid the previously problematic tension between a flavor symmetric composite sector and electro-weak precision tests. Some of the light quarks are substantially or even fully composite with striking signals at the LHC. We discuss the constraints from recent dijet mass measurements and give an outlook on the discovery potential. We also present a different protection mechanism where we separate the generation of flavor hierarchies and the origin of CP violation. This can eliminate or safely reduce unwanted CP violating effects, realizing effectively "Minimal CP Violation" and is compatible with a dynamical generation of flavor at low scales.

Towards a systematic construction of realistic D-brane models on a del Pezzo singularity

A systematic approach is followed in order to identify realistic D-brane models at toric del Pezzo singularities. Requiring quark and lepton spectrum and Yukawas from D3 branes and massless hypercharge, we are led to Pati-Salam extensions of the Standard Model. Hierarchies of masses, flavour mixings and control of couplings select higher order del Pezzo singularities, minimising the Higgs sector prefers toric del Pezzos with dP 3 providing the most successful compromise. Then a supersymmetric local string model is presented with the following properties at low energies: (i) the MSSM spectrum plus a local B − L gauge field or additional Higgs fields depending on the breaking pattern, (ii) a realistic hierarchy of quark and lepton masses and (iii) realistic flavour mixing between quark and lepton families with computable CKM and PMNS matrices, and CP violation consistent with observations. In this construction, kinetic terms are diagonal and under calculational control suppressing standard FCNC contributions. Proton decay operators of dimension 4, 5, 6 are suppressed, and gauge couplings can unify depending on the breaking scales from string scales at energies in the range 1012–1016 GeV, consistent with TeV soft-masses from moduli mediated supersymmetry breaking. The GUT scale model corresponds to D3 branes at dP 3 with two copies of the Pati-Salam gauge symmetry SU(4) × SU(2) R × SU(2) L . D-brane instantons generate a non-vanishing μ-term. Right handed sneutrinos can break the B − L symmetry and induce a see-saw mechanism of neutrino masses and R-parity violating operators with observable low-energy implications.

Neutrino masses and the scalar sector of aB−Lextension of the standard model

We consider an electroweak model based on the gauge symmetry SU(2)_L X U(1)_Y' X U(1)_B-L which has right-handed neutrinos with different exotic B-L quantum numbers. Because of this particular feature we are able to write Yukawa terms, and right-handed neutrino mass terms, with scalar fields that can develop vacuum expectation values belonging to different energy scales. We make a detailed study of the scalar and the Yukawa neutrino sectors to show that this model is compatible with the observed solar and atmospheric neutrino mass scales and the tribimaximal mixing matrix.We also show that there are dark matter candidates if a Z_2 symmetry is included.

The [formula omitted] Hubbard model on a square lattice in terms of [formula omitted] and [formula omitted] fermions and deconfined [formula omitted]-spinons and spinons

In this paper, a general description for the Hubbard model with nearest-neighbor transfer integral t and on-site repulsion U on a square lattice with Na2≫1 sites is introduced. It refers to three types of elementary objects whose occupancy configurations generate the state representations of the model extended global SO(3)×SO(3)×U(1) symmetry recently found in Ref. [11] (Carmelo and Östlund, 2010). Such objects emerge from a suitable electron–rotated-electron unitary transformation. It is such that rotated-electron single and double occupancy are good quantum numbers for U≠0. The advantage of the description is that it accounts for the new found hidden U(1) symmetry in SO(3)×SO(3)×U(1)=[SU(2)×SU(2)×U(1)]/Z22 beyond the well-known SO(4)=[SU(2)×SU(2)]/Z2 model (partial) global symmetry. Specifically, the hidden U(1) symmetry state representations store full information on the positions of the spins of the rotated-electron singly occupied sites relative to the remaining sites. Profiting from that complementary information, for the whole U/4t>0 interaction range independent spin state representations are naturally generated in terms of spin-1/2 spinon occupancy configurations in a spin effective lattice. For all states, such an effective lattice has as many sites as spinons. This allows the extension to intermediate U/4t values of the usual large-U/4t descriptions of the spin degrees of freedom of the electrons that singly occupy sites, now in terms of the spins of the singly-occupied sites rotated electrons. The operator description introduced in this paper brings about a more suitable scenario for handling the effects of hole doping. Within this, such effects are accounted for in terms of the residual interactions of the elementary objects whose occupancy configurations generate the state representations of the charge hidden U(1) symmetry and spin SU(2) symmetry, respectively. This problem is investigated elsewhere. The most interesting physical information revealed by the description refers to the model on the subspace generated by the application of one- and two-electron operators onto zero-magnetization ground states. (This is the square-lattice quantum liquid further studied in Ref. [5] (Carmelo, 2010).) However, to access such an information, one must start from the general description introduced in this paper, which refers to the model in the full Hilbert space.

A possible minimal gauge–Higgs unification

A possible minimal model of the gauge-Higgs unification based on the higher dimensional spacetime M^4 X (S^1/Z_2) and the bulk gauge symmetry SU(3)_C X SU(3)_W X U(1)_X is constructed in some details. We argue that the Weinberg angle and the electromagnetic current can be correctly identified if one introduces the extra U(1)_X above and a bulk scalar triplet. The VEV of this scalar as well as the orbifold boundary conditions will break the bulk gauge symmetry down to that of the standard model. A new neutral zero-mode gauge boson Z' exists that gains mass via this VEV. We propose a simple fermion content that is free from all the anomalies when the extra brane-localized chiral fermions are taken into account as well. The issues on recovering a standard model chiral-fermion spectrum with the masses and flavor mixing are also discussed, where we need to introduce the two other brane scalars which also contribute to the Z' mass in the similar way as the scalar triplet. The neutrinos can get small masses via a type I seesaw mechanism. In this model, the mass of the Z' boson and the compactification scale are very constrained as respectively given in the ranges: 2.7 TeV < m_Z' < 13.6 TeV and 40 TeV < 1/R < 200 TeV.