arXiv subjects

J. L. Chkareuli

Publications and source records attributed to J. L. Chkareuli.

42 records · Page 3Linked to original sources

arXiv2000

Unification Picture in Minimal Supersymmetric SU(5) Model with String Remnants

The significant heavy threshold effect is found in the supersymmetric SU(5) model with two adjoint scalars, one of which is interpreted as a massive string mode decoupled from the lower-energy particle spectra. This threshold related with the generic mass splitting of the basic adjoint moduli is shown to alter properly the running of gauge couplings, thus giving a natural solution to the string-scale grand unification as prescribed at low energies by LEP precision measurements and minimal particle content. The further symmetry condition of the (top-bottom) Yukawa and gauge coupling superunification at a string scale results in the perfectly working predictions for the top and bottom quark masses in the absence of any large supersymmetric threshold corrections.

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arXiv2000

On SUSY inspired minimal lepton number violation

A minimal lepton number violation (LNV) is proposed which could naturally appear in SUSY theories, if Yukawa and LNV couplings had a common origin. According to this idea properly implemented into MSSM with an additional abelian flavor symmetry the prototype LNV appears due to a mixing of leptons with superheavy Higgs doublet mediating Yukawa couplings. As a result, all significant physical manifestations of LNV reduce to those of the effective trilinear couplings $LL\bar{E}$ and $LQ\bar{D}$ aligned, by size and orientation in a flavor space, with the down fermion (charged lepton and down quark) effective Yukawa couplings, while the effective bilinear terms appear generically suppressed relative to an ordinary $μ$-term of MSSM. Detailed phenomenology of the model related to the flavor-changing processes both in quark and lepton sectors, radiatively induced neutrino masses and decays of the LSP is presented. Remarkably, the model can straightforwardly be extended to a Grand Unified framework and an explicit example with SU(7) GUT is thoroughly discussed.

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arXiv1999

Where does Flavour Mixing come from?

We argue that flavour mixing, both in the quark and charged lepton sector, is basically determined by the lightest family mass generation mechanism. So, in the chiral symmetry limit when the up and down quark masses vanish, all the quark mixing angles vanish. This mechanism is not dependent on the number of quark-lepton families nor on any ``vertical'' symmetry structure, unifying quarks and leptons inside a family as in Grand Unified Theories. Together with a hypothesis of maximal CP violation, the model leads to a completely predictive ansatz for all the CKM matrix elements in terms of the quark masses. Some implications for neutrino masses and oscillations are briefly discussed.

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arXiv1998

SU(N) SUSY GUTS with String Remnants: Minimal SU(5) and Beyond

A new superstring-motivated framework for a treatment of SU(N) SUSY GUTs is argued. We show that all the present difficulties of the minimal supersymmetric SU(5) model can successfully be overcome with a new renormalizable reflection-invariant superpotential with two-adjoint scalars, one of which is interpreted as a massive string mode essentially decoupled from the low-energy particle spectra. This superpotential is proved to properly fix a mass ratio of the basic adjoint scalar moduli, while its gauge-type reflection symmetry essentially protects the model from gravitational smearing. The significant heavy threshold effect related with the generic mass splitting of adjoint moduli is shown to alter appropriately the running of gauge couplings towards the realistic string-scale grand unification. Furthermore, the extension of the superpotential to some SU(N) GUTs gives rise to, among many degenerate vacua, the missing VEV vacuum configuration for the basic adjoint scalar, thus providing a further clue to a doublet-triplet splitting problem, on the one hand, and a family symmetry $SU(N-5)_F$ for quarks and leptons, on the other. We predict the existence on a TeV scale two or three families of pseudo-Goldstone bosons of type ($5+\bar{5}$) + SU(5)-singlets depending on SU(7) or SU(8) GUT selected.

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arXiv1997

New Solution to Doublet-Triplet Splitting Problem in SU(N) SUSY GUTs: Towards an Unification of Flavour

The missing VEV solution to the doublet-triplet splitting problem in general SU(N) SUSY GUTs is found. Remarkably enough, it requires a strict equality of numbers of the fundamental colours and flavours in SU(N) and for the even-order groups (N=2k) gives the predominant breaking channel $SU(N) \to SU(k-1)_c\otimes SU(k-1)_f\otimes SU(2)_w\otimes U(1)\otimes U(1)'$ in the parameter natural area. The flavour subsymmetry breaking owing to some generic string inspired extra symmetries of the Higgs superpotential appears not to affect markedly the basic adjoint vacuum configuration in the model. Thus the both salient features of SM just as an interplay between colours and flavours (or families for due assignment of quarks and leptons) so the doublet structure of the weak interactions could be properly understood and accommodated in the framework of the minimal SU(8) model. Among its predictions the most crucial one belongs to the existence on the TeV scale just three families of pseudo-Goldstone bosons and their superpartners 3(5+\bar 5) + SU(5)-singlets which noticeably improve the unification picture of MSSM.

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arXiv1996

Towards the Non-Chiral Extension of SM and MSSM

We show that in some SU(N) type GUTs with the complementary pairs of the conjugated fermion multiplets there naturally appear the relatively light ($M\ll M_{GUT}$) vectorlike fermions which considerably modify the desert physics. In the non-SUSY case they can provide for the unification of the standard coupling constant $α_1$, $α_2$ and $α_S$ whereas in the SUSY case they can increase the unification point up to the string unification limit and decrease $α_S(M_Z)$ down to the value predicted from the low energy physics.

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