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L. V. Laperashvili

Publications and source records attributed to L. V. Laperashvili.

53 records · Page 3Linked to original sources
arXiv2004

The Multiple Point Principle and Higgs Bosons

The multiple point principle (MPP), according to which several vacuum states with the same energy density exist, is put forward as a fine-tuning mechanism predicting the ratio between the fundamental and weak scales in the Standard Model (SM) and in its two Higgs doublet extension (2HDM). Using renormalization group equations for the SM, we obtain the effective potential in the 2-loop approximation and investigate the existence of its postulated second minimum at the fundamental scale. In the SM an exponentially huge ratio between the fundamental (Planck) and electroweak scales results: $\frac{Λ_{fund}}{Λ_{ew}} \sim e^{40}.$ But in the 2HDM the fundamental scale $Λ$ can vary from 10 TeV up to the Planck scale. Using the MPP, we predict the masses of the Higgs bosons.

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arXiv2004

A New Bound State $6t + 6\bar t$ and the Fundamental-Weak Scale Hierarchy in the Standard Model

The multiple point principle, according to which several vacuum states with the same energy density exist, is put forward as a fine-tuning mechanism predicting the exponentially huge ratio between the fundamental and weak scales in the Standard Model (SM). Using renormalisation group equations for the SM, we obtain the effective potential in the 2-loop approximation and investigate the existence of its postulated second minimum at the fundamental scale. A prediction is made of the existence of a new bound state of 6 top quarks and 6 anti-top quarks, formed due to Higgs boson exchanges between pairs of quarks/anti-quarks. This bound state is supposed to condense in a new phase of the SM vacuum. The existence of three vacuum states (new, weak and fundamental) solves the hierarchy problem in the SM.

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arXiv2004

The Fundamental-Weak Scale Hierarchy in the Standard Model

The multiple point principle, according to which several vacuum states with the same energy density exist, is put forward as a fine-tuning mechanism predicting the ratio between the fundamental and electroweak scales in the Standard Model (SM). It is shown that this ratio is exponentially huge: $\sim e^{40}$. Using renormalisation group equations for the SM, we obtain the effective potential in the 2-loop approximation and investigate the existence of its postulated second minimum at the fundamental scale. The investigation of the evolution of the top quark Yukawa coupling constant in the 2-loop approximation shows that, with initial values of the top Yukawa coupling in the interval $h(M_t)=0.95\pm 0.03$ (here $M_t$ is the top quark pole mass), a second minimum of the SM effective potential can exist in the region $ϕ_{min2}\approx 10^{16}-10^{22}$ GeV. A prediction is made of the existence of a new bound state of 6 top quarks and 6 anti-top quarks, formed due to Higgs boson exchanges between pairs of quarks/anti-quarks. This bound state is supposed to condense in a new phase of the SM vacuum. This gives rise to the possibility of having a phase transition between vacua with and without such a condensate. The existence of three vacuum states (new, electroweak and fundamental) solves the hierarchy problem in the SM.

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arXiv2004

Hierarchy-Problem and a Bound State of 6 t and 6 $\bar{t}$

We propose a unification of some fine-tuning problems -- really in this article only the problem of why the weak scale is so small in energy compared to a presumed fundamental scale, being say the Planck scale -- by postulating the zero or very small value of the cosmological constant not only for one but for several vacua. This postulate corresponds to what we have called the Multiple Point Principle, namely that there be many ``vacuum'' states with the same energy density. We further assume that 6 top quarks and 6 anti-top quarks can bind by Higgs exchange so strongly as to become tachyonic and form a condensate. This gives rise to the possibility of having a phase transition between vacua with and without such a condensate. The two vacua distinguished by such a condensate will have the same cosmological constant provided the top Yukawa coupling is about $1.1 \pm 0.2$, in good correspondence with the experimental value. The further requirement that this value of the Yukawa coupling, at the weak scale, be compatible with the existence of a third vacuum, with a Higgs field expectation value of the order of the fundamental scale, enforces a hierarchical scale ratio between the fundamental and weak scales of order $10^{16}$ -- $10^{20}$.

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arXiv2003

Family Replicated Gauge Group Models

Family Replicated Gauge Group models of the type SU(n)^N\times SU(m)^N, (SMG)^3 and (SMG\times U(1)_{B-L})^3 are reviewed, where SMG=SU(3)_{c}\times SU(2)_{L}\times U(1)_{Y} is the gauge symmetry group of the Standard Model, $B$ is the baryon and $L$ is the lepton numbers, respectively. It was shown that Family Replicated Gauge Group model of the latter type fits the Standard Model fermion masses and mixing angles and describes all neutrino experiment data order magnitudewise using only 5 free parameters -- five vacuum expectation values of the Higgs fields which break the Family Replicated Gauge Group symmetry to the Standard Model. The possibility of [SU(5)]^3 or [SO(10)]^3 unification at the GUT-scale \sim 10^{18} GeV also is briefly considered.

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arXiv2003

Monopoles and Family Replicated Unification

The present theory is based on the assumption that at the very small (Planck scale) distances our space-time is discrete, and this discreteness influences on the Planck scale physics. Considering our (3+1)-dimensional space-time as a regular hypercubic lattice with a parameter $a=λ_\text{P}$, where $λ_\text{P}$ is the Planck length, we have investigated a role of lattice artifact monopoles which is essential near the Planck scale if the Family replicated gauge group model (FRGGM) is an extension of the Standard Model at high energies. It was shown that monopoles have $N$ times smaller magnetic charge in FRGGM than in SM ($N$ is the number of families in FRGGM). These monopoles can give an additional contribution to beta-functions of the renormalisation group equations for the running fine structure constants $α_\text{i}(μ)$ (i=1,2,3 correspond to the U(1), SU(2), and SU(3) gauge groups of the Standard Model). We have used the Dirac relation for renormalised electric and magnetic charges. Also we have estimated the enlargement of a number of fermions in FRGGM leading to the suppression of the asymptotic freedom in the non-Abelian theory. Different role of monopoles in the vicinity of the Planck scale gives rise or to AntiGUT, or to the new possibility of unification of gauge interactions (including gravity) at the scale $μ_\text{GUT}\approx 10^{18.4}$ GeV. We discussed the possibility of the [SU(5)]$^3$ SUSY or [SO(10)]$^3$ SUSY unifications.

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arXiv2003

Proceedings to the workshops 'What comes beyond the Standard model', 2000, 2001, 2002, Volume 2: Proceedings (Part II)

Contents (Part 2): 8.Renormalization of Coupling Constants in the Minimal SUSY Models (R. B. Nevzorov, K. A. Ter-Martirosyan and M. A. Trusov) 9.Multiple Point Model and Phase Transition Couplings ...(L.V. Laperashvili, D.A. Ryzhikh and H.B. Nielsen) 10.Family Replicated Fit of All Quark and Lepton Masses and Mixings (H. B. Nielsen and Y. Takanishi) 11.Family Replicated Calculation of Baryogenesis (H. B. Nielsen and Y. Takanishi) 12. Neutrino Oscillations in Vacuum on the Large Distance (D.A. Ryzhikh and K.A. Ter-Martirosyan) 13. Possibility of an Additional Source of Time Reversal Violation for Neutrinos (R. Erdem) 14.Quark-Lepton Masses and the Neutrino Puzzle in the AGUT Model (C.D. Froggatt) 15.Neutrinos in the Family Replicated Gauge Group Model (C.D. Froggatt) (Contents of Part 1 [hep-ph/0301029]: 1.Derivation of Lorentz Invariance and Three Space Dimensions in Generic Field Theory (C D. Froggatt and H. B. Nielsen) 2.Unitary Representations, Noncompact Groups SO(q; d - q)...(N. Mankoc Borstnik, H. B. Nielsen and D. Lukman) 3.Weyl Spinor of SO(1; 13), Families of Spinors ...(A. Borstnik Bracic and N. Mankoc Borstnik) 4.A Tight Packing Problem (A. Kleppe) 5.Why so Few Particle Species? ... (D.L. Bennett and A. Kleppe) 6.About Number of Families (D. Lukman, A. Kleppe and N.S. Mankoc Borstnik) 7.Coupling Constant Unification in Spin-Charge Unifying Model ....(N. Mankoc Borstnik and H. B. Nielsen))

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arXiv2002

Proceedings to the Workshops ''What comes beyond the Standard model'' 2000,2001, VOLUME 1: Festschrift dedicated to the 60th birthday of Holger Bech Nielsen

The present volume is the collection of contributions by friends of Holger Bech Nielsen for his 60th birthday. Contents: 1.Unified internal space of spins and charges (N. Mankoc Borstnik) 2.Semitopological Q-Rings (M. Axenides) 3.Non-local axial anomalies in the Standard model (D. Melikhov, B. Stech) 4.Could there be a fourth generation? (C.D. Froggatt) 5.Another complex Bateman equation (D.B. Fairlie) 6.Non-associative loops for Holger Bech Nielsen (P.H. Frampton) 7.Particles, fluids and vortices (J.W. van Holten) 8.Results on 2D current algebras (J.L. Petersen) 9.Phase transition in gauge theories and the Planck scale physics (L.V. Laperashvili and D.A. Ryzhikh) 10.Some remarks on the 'classical' large N limit (P. Olesen) 11.String theory and the size of hadrons (L. Susskind) 12.Relativity and $c/sqrt3$ (S.I. Blinnikov, L.B. Okun and M.I. Vysotsky) 13.Vortices (Jeff Greensite)

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arXiv2002

Monopoles near the Planck Scale and Unification

Considering our (3+1)-dimensional space-time as, in some way, discrete or l attice with a parameter $a=λ_P$, where $λ_P$ is the Planck length, we have investigated the additional contributions of lattice artifact monopoles to beta-functions of the renormalisation group equations for the running fine structure constants $α_i(μ)$ (i=1,2,3 correspond to the U(1), SU(2) and SU(3) gauge groups of the Standard Model) in the Family Replicated Gauge Group Model (FRGGM) which is an extension of the Standard Model at high energies. It was shown that monopoles have $N_{fam}$ times smaller magnetic charge in FRGGM than in SM ($N_{fam}$ is the number of families in FRGGM). We have estimated al so the enlargement of a number of fermions in FRGGM leading to the suppression of the asymptotic freedom in the non-Abelian theory. We have shown that, in contrast to the case of AntiGUT when the FRGGM undergoes the breakdown at $μ=μ_G\sim 10^{18}$ GeV, we have the possibility of unification if the FRGGM-breakdown occurs at $μ_G\sim 10^{14}$ GeV. By numerical calculations we obtained an example of the unification of all gauge interactions (including gravity) at the scale $μ_{GUT}\approx 10^{18.4}$ GeV. We discussed the possibility of $[SU(5)]^3$ or $[SO(10)]^3$ (SUSY or not SUSY) unifications.

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arXiv2001

Multiple Point Model and Phase Transition Couplings in the Two-Loop Approximation of Dual Scalar Electrodynamics

The phase transition "Coulomb-confinement" in the U(1) regularized gauge theory is considered in the framework of dual Abelian Higgs model of scalar monopoles (shortly: Higgs monopole model). The effective potential analogous to the Coleman-Weinberg's one, improved by the renormalization group equation, is constructed, using beta-functions in the two-loop approximation. The value of QED critical fine structure constant was calculated: $α_{crit}\approx 0.208$, in correspondence with lattice result: $α_{crit}^{lat}\approx 0.20\pm 0.015$.

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arXiv2001

Phase Transition in Gauge Theories and Multiple Point Model

In the present paper the phase transition in the regularized U(1) gauge theory is investigated using the dual Abelian Higgs model of scalar monopoles. The corresponding renormalization group improved effective potential, analogous to the Coleman-Weinberg's one, was considered in the two-loop approximation for $β$ functions, and the phase transition (critical) dual and non-dual couplings were calculated in the U(1) gauge theory. It was shown that the critical value of the renormalized electric fine structure constant $α_{\text{crit}}\approx 0.208$ obtained in this paper coincides with the lattice result for compact QED: $α_{\text{crit}}^{\text{lat}}\approx 0.20\pm 0.015$. This result and the behavior of $α$ in the vicinity of the phase transition point were compared with the Multiple Point Model prediction for the values of $α$ near the Planck scale. Such a comparison is very encouraging for the Multiple Point Model assuming the existence of the multiple critical point at the Planck scale.

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arXiv2001

Phase Transition in Gauge Theories and the Planck Scale Physics

The present paper is based on the modified part of the review "Random Dynamics and Multiple Point Model" by L.V.Laperashvili, H.B.Nielsen, D.A.Ryzhikh and N.Stillits, in preparation for publication in Russian, which contains the results of our joint activity with H.B.Nielsen concerning the investigations of phase transitions in gauge theories. In this review we have presented the main ideas of the Nielsen's Random Dynamics (RD) and his achievements (with co-authors) in the Anti-Grand Unification Theory (AGUT) and Multiple Point Model (MPM). We have considered also the theory of Scale Relativity (SR) by L.Nottale, which has a lot in common with RD: both theories lead to the discreteness of our space-time, giving rise to the new description of physics at very small distances. In this paper we have demonstrated the possibility of [SU(5)]$^3$ SUSY unification with superparticles of masses $M\approx 10^{18.3}$ GeV and calculated its critical point -- critical value of the inverse finestucture constant -- at $α_{5,crit}^{-1} = α_5^{-1}(μ_{Pl})\approx 34.0$ (close to $α_{GUT}^{-1}\approx 34.4$) with a hope that such an unified theory approaches the (multi)critical point at the Planck scale.

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arXiv1999

Dirac Relation and Renormalization Group Equations for Electric and Magnetic Fine Structure Constants

The quantum field theory describing electric and magnetic charges and revealing a dual symmetry was developed in the Zwanziger formalism. The renormalization group (RG) equations for both fine structure constants - electric $α$ and magnetic $\tilde α$ - were obtained. It was shown that the Dirac relation is valid for the renormalized $α$ and $\tilde α$ at the arbitrary scale, but these RG equations can be considered perturbatively only in the small region: $0.25 \stackrel{<}{\sim} α, \tilde α\stackrel{<}{\sim} 1$ with $\tilde α$ given by the Dirac relation: $α{\tilde α}$ = 1/4.

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arXiv1999

Phase Transition Couplings in the Higgsed Monopole Model

Using a one-loop approximation for the effective potential in the Higgs model of electrodynamics for a charged scalar field, we argue for the existence of a triple point for the renormalized (running) values of the selfinteraction $λ$ and the "charge" g given by $(λ_{run}, g^2) = (-{10/9} π^2,{4/3}\sqrt{5/3}{π^2}) \approx(-11, 17)$. Considering the beta-function as a typical quantity we estimate that the one-loop approximation is valid with accuracy of deviations not more than 30% in the region of the parameters: $0.2 \stackrel{<}{\sim}{\large α, \tildeα} \stackrel{<}{\sim}1.35.$ The phase diagram given in the present paper corresponds to the above-mentioned region of $α, \tilde α$. Under the point of view that the Higgs particle is a monopole with a magnetic charge g, the obtained electric fine structure constant turns out to be $α_{crit}\approx{0.18_5}$ by the Dirac relation. This value is very close to the $α_{crit}^{lat}\approx{0.20}$ which in a U(1) lattice gauge theory corresponds to the phase transition between the "Coulomb" and confinement phases. Such a result is very encouraging for the idea of an approximate "universality" (regularization independence) of gauge couplings at the phase transition point. This idea was suggested by the authors in their earlier papers.

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arXiv1997

Anti-Grand Unification and Critical Coupling Universality

The present work considers the phase transition between the confinement and "Coulomb" phases in U(1), SU(2) and SU(3)-sectors of Anti-grand unified theory described by regularized Wilson loop action. It was shown the independence of the critical coupling constants of the regularization method ("universality").

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arXiv1997

The Effective QCD Lagrangian and Renormalization Group Approach

The perturbative part of the effective QCD Lagrangian was constructed by the renormalization group approach in the 4-loop approximation. It was extrapolated in the non-perturbative region under the assumption of the existence of gluon condensate at (F_{μν}^j)^2=F_0^2. The best result is F_0^2\approx 0.4 GeV^4.

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