In collaboration with Jogesh Pati, Abdus Salam challenged the chiral gauge nature of the Standard Model by paving the road towards the Left-Right ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
2017 - World Scientific | Modern Physics Letters A
K. S. Babu, Jogesh C. Pati, Zurab Tavartkiladze,
We present a class of realistic unified models based on supersymmetric SO(10) wherein issues related to natural doublet-triplet (DT) splitting are fully resolved. Using a minimal set of low dimensional Higgs fields which includes a single adjoint, we show that the Dimopoulos-Wilzcek mechanism for DT splitting can be made stable in the presence of all higher order operators without having pseudo-Goldstone bosons and flat directions. The μ term of order TeV is found to be naturally induced. A Z 2-assisted ...
Tópico(s): Neutrino Physics Research
2010 - Springer Nature | Journal of High Energy Physics
A framework based on an effective symmetry that is either $\mathrm{G}(224)=\mathrm{SU}{(2)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}{(2)}_{R}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}{(4)}^{c}$ or SO(10) has been proposed (a few years ago) that successfully describes the masses and mixings of all fermions including neutrinos, with seven predictions, in good accord with the data. Baryogenesis via leptogenesis is considered within this framework by allowing for natural phases $(\ensuremath{\sim} ...
Tópico(s): Dark Matter and Cosmic Phenomena
2003 - American Physical Society | Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields
Evidence in favor of supersymmetric grand unification including that based on the observed family multiplet-structure, gauge coupling unification, neutrino oscillations, baryogenesis, and certain intriguing features of quark-lepton masses and mixings is noted. It is argued that attempts to understand (a) the tiny neutrino masses (especially Delta m^2 (nu_2 -nu_3)), (b) the baryon asymmetry of the universe (which seems to need leptogenesis), and (c) the observed features of fermion masses such as the ratio ...
Tópico(s): Dark Matter and Cosmic Phenomena
2003 - World Scientific | International Journal of Modern Physics A
K. S. Babu, Jogesh C. Pati, Frank Wilczek,
Within the framework of unified gauge models, interactions responsible for neutrino masses can also provide mechanisms for nucleon instability. We discuss their implications concretely in the light of recent results on neutrino oscillation from the SuperKamiokande collaboration. We construct a predictive SO(10)-based framework that describes the masses and mixing of all quarks and leptons. An overconstrained global fit is obtained, that makes five successful predictions for quarks and charged leptons. ...
Tópico(s): Dark Matter and Cosmic Phenomena
2000 - Elsevier BV | Nuclear Physics B
It is remarked that the SuperKamiokande (SK) discovery of $\nu_\mu$ to $\nu_\tau$ (or $\nu_X$)-oscillation, with a $\delta m^2 \approx 10^{-2}-10^{-3} eV^2$ and $sin^2 2 \theta > 0.8$, provides a clear need for the right-handed (RH) neutrinos. This in turn reinforces the ideas of the left-right symmetric gauge structure $SU(2)_L \times SU(2)_R$ as well as SU(4)-color, for which the RH neutrinos are a compelling feature. It is noted that by assuming (a) that B-L and $I_{3R}$, contained in a string-derived $G(224) = SU( ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1999 - Elsevier BV | Nuclear Physics B - Proceedings Supplements
K. S. Babu, Jogesh C. Pati, Frank Wilczek,
We show that in supersymmetric unified theories such as SO(10), implementation of the see–saw mechanism for neutrino masses introduces a new set of color triplet fields and thereby a new source of d=5 proton decay operators. For neutrino masses in a plausible range, these operators are found to have the right strength to yield observable, but not yet excluded, proton decay rates. The flavor structure of the new operators is distinctive. Proton decay modes into a charged lepton, such as ℓ+π0, ℓ+K0 ...
Tópico(s): Astrophysics and Cosmic Phenomena
1998 - Elsevier BV | Physics Letters B
Alon E. Faraggi, Jogesh C. Pati,
Tópico(s): Quantum Chromodynamics and Particle Interactions
1998 - Elsevier BV | Nuclear Physics B
The paper addresses the problem of suppressing naturally the unsafe d = 4 as well as the color-triplet mediated and/or gravity-linked d = 5 proton-decay operators, which generically arise in SUSY-unification. It also attempts to give light masses to the neutrinos, of the type suggested by current experiments. It is noted that neither the symmetries in SO(10), nor those in E6, suffice for the purpose - especially in the matter of suppressing naturally the d = 5 proton-decay operators. By contrast, it is ...
Tópico(s): Astrophysics and Cosmic Phenomena
1996 - Elsevier BV | Physics Letters B
The commonly accepted notion of a weak unified coupling $\alpha_X \approx 0.04$, based on the assumption of the MSSM--spectrum, is questioned. It is suggested that the four--dimensional unified string coupling should very likely have an intermediate value $(\sim 0.2-0.3$, say) so that it may be large enough to stabilize the dilaton but not so large as to disturb the coupling--unification relations. Bearing this in mind, as well as the smallness of the MSSM unification scale $M_X$ compared to the string ...
Tópico(s): Dark Matter and Cosmic Phenomena
1996 - Elsevier BV | Physics Letters B
K. S. Babu, Jogesh C. Pati, Frank Wilczek,
We show how two different scales for oscillations between $e$ and $\mu$ neutrinos, characterized by different mixing angles and effective mass scales, can arise in a simple and theoretically attractive framework. One scale characterizes direct oscillations, which can accommodate the MSW approach to the solar neutrino problem, whereas the other can be considered as arising indirectly, through virtual transitions involving the $\tau$ neutrino with a mass $\sim$ 1 eV. This indirect transition allows the possibility ...
Tópico(s): Astrophysics and Cosmic Phenomena
1995 - Elsevier BV | Physics Letters B
Universal strong, weak, and electromagnetic interactions of leptons and hadrons are generated by gauging a non-Abelian renormalizable anomaly-free subgroup of the fundamental symmetry structure $\mathrm{SU}{(4)}_{L}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}{(4)}_{R}\ifmmode\times\else\texttimes\fi{}\mathrm{SU}({4}^{\ensuremath{'}})$, which unites three quartets of colored baryonic quarks and the quartet of known leptons into 16-folds of chiral fermionic multiplets, with lepton number treated as ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1994 - Cambridge University Press | World Scientific series in 20th century physics
K. S. Babu, Jogesh C. Pati, H. Stremnitzer,
In the context of the minimal flavon-chromon preon model, we show that supersymmetry, because of fermion-boson pairing in its field content, provides a rather simple reason for replication of composite quark-lepton families. At the level of minimum number of core constituents, which turns out to be three, it also provides a good reason why one may expect to have just three light chiral families. One crucial prediction is that there must exist complete vector-like families with mass of order 1 TeV ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1991 - Elsevier BV | Physics Letters B
K. S. Babu, Jogesh C. Pati, H. Stremnitzer,
It is observed that the scale-unifying model based on supersymmetry and compositeness provides a natural reason for the family mass hierarchy m${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathit{e}}$\ensuremath{\ll}m${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathrm{\ensuremath{\mu}}}$\ensuremath{\ll}m${\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}_{\mathrm{\ensuremath{\tau}}}$ and links spontaneous CP violation to the nonvanishing mass of the electron family. Some of its predictions ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1991 - American Physical Society | Physical Review Letters
It is proposed that the hierarchical scales — from MPlanck to mv — have a common origin. Using MPlanck and the coupling constant associated with a preonic metacolor gauge force as the only input parameters, it is shown how large ratios such as (MP1MI), (MP1δms), (MP1mw), (MP1mt) and even (MP1mv)≳1027 can arise naturally. Here MI denotes an intermediate scale ∼1011 GeV, which is identified with the scale parameter of the metacolor force, while δms denotes SUSY-breaking mass splittings ∼ 1 TeV. Local supersymmetry ...
Tópico(s): Noncommutative and Quantum Gravity Theories
1989 - Elsevier BV | Physics Letters B
Jogesh C. Pati, Mirjam Cveti, H. S. Sharatchandra,
A resolution of one of the major dilemmas of preon dynamics, i.e., why (${m}_{q}$,${m}_{l}$)\ensuremath{\ll}(1/${r}_{0}$)\ensuremath{\equiv}${\ensuremath{\Lambda}}_{0}$, is provided. In a class of models, supersymmetry (SUSY) in its local rather than global form permits a breaking of SUSY and also a generation of composite-fermion masses, but both with a severe damping by powers of (${\ensuremath{\Lambda}}_{0}$/${M}_{\mathrm{Planck}}$).
Tópico(s): Noncommutative and Quantum Gravity Theories
1987 - American Physical Society | Physical Review Letters
Jogesh C. Pati, H. Stremnitzer,
It is argued that the family replication model of composite quarks and leptons, and the fermion mass-matrix therein require that the branching ratio of the decay KL → e− μ+ should exceed at least 13 × 10−10. There is likewise a lower limit on K → πμe. These serve as crucial tests of the replication idea.
Tópico(s): High-Energy Particle Collisions Research
1986 - Elsevier BV | Physics Letters B
Tristan Hübsch, Hitoshi Nishino, Jogesh C. Pati,
Tópico(s): Black Holes and Theoretical Physics
1985 - Elsevier BV | Physics Letters B
Darwin Chang, Rabindra N. Mohapatra, Palash B. Pal, Jogesh C. Pati,
It is shown that spontaneous breakdown of parity within left-right-symmetric theories can be entirely responsible for generating a spontaneous breakdown of "isospin" symmetry leading to large up-down mass splitting within a family.
Tópico(s): Dark Matter and Cosmic Phenomena
1985 - American Physical Society | Physical Review Letters
It is observed that the assumptions that quarks and leptons are composites and that they acquire masses dynamically through preonic condensates rather than through the vacuum expectation value of a Higgs field lead to a relatively low upper bound of only 1 to 3 TeV for the inverse size of the heaviest family---e.g., the $\ensuremath{\tau}$ family. It is furthermore stressed that the $e$ and $\ensuremath{\mu}$ families, within a large class of models, must, on the other hand, have a relatively large inverse ...
Tópico(s): Dark Matter and Cosmic Phenomena
1984 - American Physical Society | Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields
Following the recent observation that within SU(4) of color unifying quarks with leptons there exists a simple mechanism which emphasizes the $\ensuremath{\Delta}(B\ensuremath{-}L)=\ensuremath{-}2$ decays of a nucleon into a single lepton + mesons, it is noted that a variant of the same mechanism leads to decays of the nucleon into lepton + lepton + antilepton + mesons without any suppression in the amplitude. For an economical choice of the scalar system, nucleon decays into $\mathrm{ll}\overline{l}$ + mesons ...
Tópico(s): Black Holes and Theoretical Physics
1984 - American Physical Society | Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields
Mirjam Cvetič, Jogesh C. Pati,
We present a model which links N = 1 supergravity with the minimal left-right symmetric model, based on the gauge symmetry SU(2)L × SU(2)R × U(1)B−L and a minimal set of Higgs fields. The gravitino mass, which is the only relevant low energy scale for the model, sets the scale for the mass of WR, while the mass of WL arises radiatively. It is observed that barring unnatural fine tuninng of parameters, the hierarchy ratio ν = (mWR/mWL is bounded above by a number of order ten. The mass spectrum of the model ...
Tópico(s): Cosmology and Gravitation Theories
1984 - Elsevier BV | Physics Letters B
Using the supersymmetry and R-breaking mechanism induced by N=1 supergravity, we develop the minimal flavon-chromon preonic model where spin-12 and spin-0 components of four preonic chiral multiplets correspond to flavons and chromons, from which quarks and leptons are made as composites. The emergence of the concepts of flavour and colour, in this minimal model, is synonymous with R and supersymmetry breaking. This breaking also gives a heavy mass to the gaugino, which is necessary for the implementation ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1984 - Elsevier BV | Nuclear Physics B
We suggest a flavon-chromon preon model possessing two preonic scales - ΛM⪢1 TeV and ΛH ∼ 1 TeV - associated with metacolor and hypercolor gauge forces respectively. The model exhibits two desirable features: (a) a mechanism for family replication, and (b) a new mechanism for interfamily mass hierarchy. With a minimal choice of the preonic fields, the model predicts four families (e, μ, τ and τ′), τ being a replication of e and τ′ of μ. Barring mixing, the e- and μ-families lies are bound by the metacolor ...
Tópico(s): Particle physics theoretical and experimental studies
1984 - Elsevier BV | Physics Letters B
Jogesh C. Pati, Abdus Salam, Utpal Sarkar,
Tópico(s): Black Holes and Theoretical Physics
1983 - Elsevier BV | Physics Letters B
Tópico(s): Cosmology and Gravitation Theories
1983 - Elsevier BV | Nuclear Physics B
Jogesh C. Pati, Abdus Salam, J. Strathdee,
Tópico(s): High-Energy Particle Collisions Research
1982 - Elsevier BV | Physics Letters B
Jogesh C. Pati, Abdus Salam, J. Strathdee,
Tópico(s): Quantum Chromodynamics and Particle Interactions
1981 - Elsevier BV | Nuclear Physics B
It is argued that ordinary "electric"-type forces - abelian or nonabelian - arising within the grand unification hypothesis are inadequate to bind preons to make quarks and lepton unless we proliferate preons. It is therefore suggested that the preons carry electric and magnetic charges and that their binding force is magnetic. Quarks and leptons are magnetically neutral. Possible consistency of this suggestion with the known phenomena and possible origin of magnetic charges are discussed.
Tópico(s): Cosmology and Gravitation Theories
1981 - Elsevier BV | Physics Letters B
Jogesh C. Pati, Abdus Salam, J. Strathdee,
Violation of baryon, lepton and in general fermion number is central to the hypothesis of quark-lepton unification in a gauge context. Three of its characteristic signatures are proton decay, n-n oscillation and neutrinole double β decay. In 1974 and 1975 it was shown that within maximal gauging the proton may decay via four alternative modes (i.e. proton → one or three lepton or antileptons) satisfying ΔF = −2, 0, −4 and −6, some of which may coexist; the deuteron may decay into pions and neutrinoless ...
Tópico(s): Quantum Chromodynamics and Particle Interactions
1981 - Elsevier BV | Nuclear Physics B