3,550 research outputs found

    A Separate Higgs?

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    We investigate the possibility of a multi-Higgs doublet model where the lightest neutral Higgs boson (h0h^0) decouples from the fermion sector. We are partially motivated by the four ℓ+ℓ−γγ\ell^+\ell^-\gamma\gamma events with Mγγ≃60M_{\gamma\gamma}\simeq60\,GeV recently observed by the L3 collaboration, which could be a signal for Z→(Z∗→ℓ+ℓ−)+(h0→γγ)Z\to (Z^*\to \ell^+\ell^-)+(h^0\to \gamma\gamma). Collider signatures for the additional physical Higgs bosons present in such models are discussed.Comment: 8 pages (plus 2 figures, available by request), latex, ANL-HEP-PR-92-10

    Role of ABA Signaling in Regulation of Stem Sugar Metabolism and Transport under Post- Flowering Drought Stress in Sweet Sorghum

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    Sugar remobilization from vegetative to reproductive tissues is an important process that determines grain yield in crops. Sweet sorghum stems store sugar and introgression of Stay green1 (Stg 1) locus from the grain sorghum genotype B35 into the sweet sorghum genotype S35 was previously shown to bring about a 2-fold higher stem sugar accumulation in the near-isogenic line (NIL) S35SG06040. We hypothesized that remobilization of stem sugar augments grain yield on exposure to drought stress and that the phytohormone abscisic acid (ABA) has a role to play in this process. ABA levels were three times higher in the NIL as compared to those in S35 on drought stress exposure. Remobilization of stem sugars in the NIL was evident by the observed decrease in reducing sugar content in the stem but not in the peduncle in response to prolonged drought stress exposure. Drought-induced expression of some ABA response factors (ABFs) as well as invertase and sucrose transporter genes was seen to be higher in the NIL as compared to S35. An over-representation of ABA-responsive elements (ABREs) and sugar signaling motifs in the differentially expressed genes indicated the involvement of ABA and sugar signaling in regulation of their expression. Two ABF genes located on the Stg1 locus showed single nucleotide polymorphism, which possibly accounted for their differential regulation in S35 and the NIL. The results suggest that ABA signaling plays an important role in post-flowering drought-induced remobilization of sugars to the reproductive sinks

    Left-Right Symmetry and Supersymmetric Unification

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    The existence of an SU(3) X SU(2)_L X SU(2)_R X U(1) gauge symmetry with g_L = g_R at the TeV energy scale is shown to be consistent with supersymmetric SO(10) grand unification at around 1O^{16} GeV if certain new particles are assumed. The additional imposition of a discrete Z_2 symmetry leads to a generalized definition of R parity as well as highly suppressed Majorana neutrino masses. Another model based on SO(10) X SO(10) is also discussed.Comment: 11 pages, 2 figures not included, UCRHEP-T124, Apr 199

    Page curves and typical entanglement in linear optics

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    Bosonic Gaussian states are a special class of quantum states in an infinite dimensional Hilbert space that are relevant to universal continuous-variable quantum computation as well as to near-term quantum sampling tasks such as Gaussian Boson Sampling. In this work, we study entanglement within a set of squeezed modes that have been evolved by a random linear optical unitary. We first derive formulas that are asymptotically exact in the number of modes for the R\'enyi-2 Page curve (the average R\'enyi-2 entropy of a subsystem of a pure bosonic Gaussian state) and the corresponding Page correction (the average information of the subsystem) in certain squeezing regimes. We then prove various results on the typicality of entanglement as measured by the R\'enyi-2 entropy by studying its variance. Using the aforementioned results for the R\'enyi-2 entropy, we upper and lower bound the von Neumann entropy Page curve and prove certain regimes of entanglement typicality as measured by the von Neumann entropy. Our main proofs make use of a symmetry property obeyed by the average and the variance of the entropy that dramatically simplifies the averaging over unitaries. In this light, we propose future research directions where this symmetry might also be exploited. We conclude by discussing potential applications of our results and their generalizations to Gaussian Boson Sampling and to illuminating the relationship between entanglement and computational complexity.Comment: 29 pages; 2 figures. Version 2: small updates to match journal versio

    Intermediate scale as a source of lepton flavor violation in SUSY SO(10)

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    In supersymmetric SO(10) grand unified models, we examine the lepton flavor violation process μ→eγ\mu \rightarrow e\gamma from having the SU(2)R×_R\times U(1)B−L_{B-L} gauge symmetry broken at an intermediate scale MIM_I below the SO(10) grand unification scale MGM_G. Even in the case that supersymmetry is broken by universal soft terms introduced at the scale MGM_G, we find significant rates for μ→eγ\mu\rightarrow e\gamma with MI∼1012M_I \sim 10^{12} GeV or less. These rates are further enhanced if the universal soft terms appear at a scale greater than MGM_G.Comment: 12 pages (Latex), 3 PS Figures (uuencoded, epsf.tex), small addition to discussion in the text, as to appear in Phys. Rev. D Rapid Communication

    Texture of fermion mass matrices in partially unified theories

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    We investigate the texture of fermion mass matrices in theories with partial unification (for example SU(2)L×SU(2)R×SU(4)c SU(2)_L\times SU(2)_R\times SU(4)_c) at a scale ∼1012\sim 10^{12} GeV. Starting with the low energy values of the masses and the mixing angles, we find only two viable textures with atmost four texture zeros. One of these corresponds to a somewhat modified Fritzsch textures. A theoretical derivataion of these textures leads to new interesting relations among the masses and the mixing angles.Comment: 10 pages(Latex

    Constraints from b→sγb \to s \gamma on gauge-mediated supersymmetry breaking models

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    We consider the branching ratio of b→sγb \to s\gamma in gauge mediated supersymmetry breaking theories. Useful bounds on the parameter space of these models are derived from the experimental bounds on b→sγb \to s\gamma. Constraints on masses of NLSP are presented as a function of tanβtan\beta and M/ΛM/\Lambda for μ0\mu0.Comment: 12 pages(Latex), 3 PS Figures (uuencoded, epsf.tex); minor modification in the introductory part of the tex

    SUSY GUTs contributions and model independent extractions of CP phases

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    We consider the origin of new phases in supersymmetric grand unification model, and show how significant new contributions arise from the gluino mediated diagram. We then present a more general model independent analysis of various modes of B-decays suggested previously for measurement of the CKM phases and point out what they really measure. It is in principle possible to separate out all the phases.Comment: 13 pages (Latex), 2 PS figures, a few remarks are added and a typo is corrected. To appear in Phys. Rev. Let

    Ab Initio Calculations of the Walls Shear Strength of Carbon Nanotubes

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    The dependence of the energy of interwall interaction in double-walled carbon nanotubes (DWNT) on the relative position of walls has been calculated using the density functional method. This dependence is used to evaluate forces that are necessary for the relative telescopic motion of walls and to calculate the shear strength of DWNT for the relative sliding of walls along the nanotube axis and for their relative rotation about this axis. The possibility of experimental verification of the obtained results is discussed.Comment: 4 pages, 1 figur

    New physics effects to the lepton polarizations in the B -> K l^+ l^- decay

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    Using the general, model independent form of the effective Hamiltonian, the general expressions of the longitudinal, normal and transversal polarization asymmetries for (l^-) and (l^+) and combinations of them for the exclusive (B -> K l^+ l^-) decay are found. The sensitivity of lepton polarizations and their combinations on new Wilson coefficients are studied. It is found that there exist regions of Wilson coefficients for which the branching ratio coincides with the Standard Model result while the lepton polarizations differ substantially from the standard model prediction. Hence, studying lepton polarization in these regions of new Wilson coefficients can serve as a promising tool for establishing new physics beyond the Standard Model.Comment: 18 pp, 14 figures (postscript formatted), LaTex formatte
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