14815248
Phenomenological study of lepton mass matrix textures
The three active light neutrinos are used to explain the neutrino oscillations. The inherently bi-large mixing neutrino mass matrix and the Fritzsch type, bi-small mixing charged lepton mass matrix are assumed. By requiring the maximal �µ −�� mixing for the atmospheric neutrino problem and the masssquared difference approperiate for the almost maximal mixing solution to
11525411
A Model for neutrino warm dark matter and neutrino oscillations
Abstract The muon- and tau-neutrinos with the mass in the keV range, which are allowed in a low reheating temperature cosmology, can compose the warm dark matter of the universe. A model of four light neutrinos including the keV scale ν μ and ν τ is studied, which combines the seesaw mechanism and the Abelian flavor symmetry. The atmospheric neutrino anomaly is due to the ν μ – ν τ oscillation. The solar neutrino problem is answered by the oscillation into the light sterile neutrino, where the SMA, LMA, and LOW–QVO solutions can be accommodated in our scenario.
11586065
Scenario of light sterile neutrinos with a heavy tau neutrino in a supersymmetric model
Three light sterile neutrinos (nu (s)(e), nu (s)(mu) and nu (s)(tau)) are introduced to accommodate all the available neutrino data: the atmospheric neutrino anomaly is explained by nu (mu)-nu (s)(mu) oscillation with maximal mixing; the solar one is due to nu (e)-nu (s)(e) oscillation of small angle Mikheyev-Smirnov-Wolfenstein type; the Liquid Scintillation Neutrino Detector data is from v(e)-v(mu) oscillations, so that the neutrinos can be the hot component of the dark matter. The big bang nucleosynthesis constraint is satisfied by taking the tau neutrino to be 10 MeV heavy. The nu (tau) decay is discussed in a model of gauge mediated supersymmetry breaking. The decay mode v(tau) --> (G) over tilde gamma with (G) over tilde being the gravitino is proposed. The nu (tau) has a rather long lifetime similar to 10(3)-10(13) s. Its implication to the gamma-ray burst is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.
119422313
Spin configuration of top quark pair production with large extra dimensions at photon-photon colliders
Top quark pair production at photon-photon colliders is studied in low scale quantum gravity scenario. From the dependence of the cross sections on the spin configuration of the top quark and anti-quark, we introduce a new observable, top spin asymmetry. It is shown that there exists a special top spin basis where with the polarized parent electron beams the top spin asymmetry vanishes in the standard model but retains substantial values with the large extra dimension effects. We also present lower bounds of the quantum gravity scale $M_S$ from total cross sections with various combinations of the laser, electron beam, and top quark pair polarizations. The measurements of the top spin state $(t_\uparrow\bar{t}_\downarrow)$ with unpolarized initial beams are shown to be most effective, enhancing by about 5% the $M_S$ bounds with respect to totally unpolarized case.
16221979
POLARIZATION EFFECTS ON THE E+E- W+W- PROCESS WITH LARGE EXTRA DIMENSIONS
Abstract We study large extra dimension effects on the polarizations of the W pair and electron beam at the e + e − → W + W − process. It is shown that the measurements of the cross section for transversely polarized W pair with the right-handed electron beam remarkably enhance the possibilities to see the low scale quantum gravity effects. Higher Linear Collider bounds on the string scale in this model can be obtained by using the left-handed electron beam.
14893616
Z boson pair production at CERN LHC in a stabilized Randall-Sundrum scenario
We study the Z boson pair production at LHC in the Randall-Sundrum scenario with the Goldberger-Wise stabilization mechanism. It is shown that comprehensive account of the Kaluza-Klein graviton and radion effects is crucial to probe the model: The KK graviton effects enhance the cross section of $g g \to Z Z$ on the whole so that the resonance peak of the radion becomes easy to detect, whereas the RS effects on the $q\bar{q} \to Z Z$ process are rather insignificant. The $p_T$ and invariant-mass distributions are presented to study the dependence of the RS model parameters. The production of longitudinally polarized Z bosons, to which the SM contributions are suppressed, is mainly due to KK gravitons and the radion, providing one of the most robust methods to signal the RS effects. The $1 \sigma$ sensitivity bounds on $(\Lambda_\pi, m_\phi)$ with $k/M_{\rm Pl} =0.1$ are also obtained such that the effective weak scale $\Lambda_\pi$ of order 5 TeV can be experimentally probed.
18394237
The Hurwitz Enumeration Problem of Branched Covers and Hodge Integrals
We use algebraic methods to compute the simple Hurwitz numbers for arbitrary source and target Riemann surfaces. For an elliptic curve target, we reproduce the results previously obtained by string theorists. Motivated by the Gromov-Witten potentials, we find a general generating function for the simple Hurwitz numbers in terms of the representation theory of the symmetric group S{sub n}. We also find a generating function for Hodge integrals on the moduli space {bar M}{sub g,2} of Riemann surfaces with two marked points, similar to that found by Faber and Pandharipande for the case of one marked point.
14366436
Superconformal indices for orbifold Chern-Simons theories
We calculate the superconformal indices of recently discovered three-dimensional N = 4,5 Chern-Simons-matter theories and compare them with the corresponding indices of supergravity on AdS4 times orbifolds of S^7 in the large N and large k limit. We find perfect agreement for orbifolds without fixed locus, and argue that the agreement can continue to hold for orbifolds with fixed locus provided that the mass shifts of the twisted sector states are properly taken into account. We also discuss the index for the so-called "dual ABJM" proposal.
14989133
Three-Dimensional Gorenstein Singularities and SU(3) Modular Invariants
Using N=2 Landau-Ginzburg theories, we examine the recent conjectures relating the SU(3) WZW modular invariants, finite subgroups of SU(3) and Gorenstein singularities. All isolated three-dimensional Gorenstein singularities do not appear to be related to any known Landau-Ginzburg theories, but we present some curious observations which suggest that the SU(3)_n/SU(2)xU(1) Kazama-Suzuki model may be related to a deformed geometry of C^3/Z_{n+3}xZ_{n+3}. The toric resolution diagrams of those particular singularities are also seen to be classifying the diagonal modular invariants of the SU(3)_n as well as the SU(2)_{n+1} WZW models.
1563485
Quiver tails and N=1$$ \mathcal{N}=1 $$ SCFTs from M5-branes
A bstractWe study a class of four-dimensional N=1$$ \mathcal{N}=1 $$ superconformal field theories obtained by wrapping M5-branes on a Riemann surface with punctures. We identify fourdimensional UV descriptions of the SCFTs corresponding to curves with a class of punctures. The quiver tails appearing in these UV descriptions differ significantly from their N=2$$ \mathcal{N}=2 $$ counterpart. We find a new type of object that we call the ‘Fan’. We show how to construct new N=1$$ \mathcal{N}=1 $$ superconformal theories using the Fan. Various dual descriptions for these SCFTs can be identified with different colored pair-of-pants decompositions. For example, we find an N=1$$ \mathcal{N}=1 $$ analog of Argyres-Seiberg duality for the SU(N ) SQCD with 2N flavors. We also compute anomaly coefficients and superconformal indices for these theories and show that they are invariant under dualities.
119109178
The Seiberg-Witten Kähler potential as a two-sphere partition function
A bstractRecently it has been shown that the two-sphere partition function of a gauged linear sigma model of a Calabi-Yau manifold yields the exact quantum Kähler potential of the Kähler moduli space of that manifold. Since four-dimensional $\mathcal{N}=2$ gauge theories can be engineered by non-compact Calabi-Yau threefolds, this implies that it is possible to obtain exact gauge theory Kähler potentials from two-sphere partition functions. In this paper, we demonstrate that the Seiberg-Witten Kähler potential can indeed be obtained as a two-sphere partition function. To be precise, we extract the quantum Kähler metric of 4D $\mathcal{N}=2$ SU(2) Super-Yang-Mills theory by taking the field theory limit of the Kähler parameters of the $\mathcal{O}$(−2, −2) bundle over ${{\mathbb{P}}^1}\times {{\mathbb{P}}^1}$. We expect this method of computing the Kähler potential to generalize to other four-dimensional $\mathcal{N}=2$ gauge theories that can be geometrically engineered by toric Calabi-Yau threefolds.