4,238 research outputs found

    New correlations induced by nuclear supersymmetry

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    We show that the nuclear supersymmetry model (n-susy) in its extended version, predicts correlations in the nuclear structure matrix elements which characterize transfer reactions between nuclei that belong to the same supermultiplet. These correlations are related to the fermionic generators of the superalgebra and if verified experimentally can provide a direct test of the model.Comment: Invited talk at "Nuclear Physics: Large and Small", April 19-22, 2004, Hacienda Cocoyoc, Mexic

    Supersymmetric Contributions to Weak Decay Correlation Coefficients

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    We study supersymmetric contributions to correlation coefficients that characterize the spectral shape and angular distribution for polarized muon- and beta-decays. In the minimal supersymmetric Standard Model (MSSM), one-loop box graphs containing superpartners can give rise to non-(V-A)x(V-A) four fermion operators in the presence of left-right or flavor mixing between sfermions. We analyze the present phenomenological constraints on such mixing and determine the range of allowed contributions to the weak decay correlation coefficients. We discuss the prospective implications for future muon- and beta-decay experiments, and argue that they may provide unique probes of left-right mixing in the first generation scalar fermion sector.Comment: Revised version - to appear in Phys.Rev.

    Supersymmetric contributions to weak decay correlation coefficients

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    We study supersymmetric contributions to correlation coefficients that characterize the spectral shape and angular distribution for polarized µ- and beta-decays. In the minimal supersymmetric standard model (MSSM), one-loop box graphs containing superpartners can give rise to non-(V-A)[direct-product](V-A) four-fermion operators in the presence of left-right or flavor mixing between sfermions. We analyze the present phenomenological constraints on such mixing and determine the range of allowed contributions to the weak decay correlation coefficients. We discuss the prospective implications for future µ- and beta-decay experiments, and argue that they may provide unique probes of left-right mixing in the first generation scalar fermion sector

    Implications of Gauge Unification for Time Variation of the Fine Structure Constant

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    Unification of the gauge couplings would imply that time variations of the fine structure constant are accompanied by calculable and very significant time variations in the QCD scale parameter ΛQCD\Lambda_{QCD}. Since ΛQCD\Lambda_{QCD} is the dominant factor in setting the hadron masses, estimates made by simple variations of the fine structure constant may not provide meaningful limits. There may also be related variations in Yukawa couplings and the electroweak scale. Implications for the 21 cm hyperfine transition, big bang nucleosynthesis, and the triple alpha process are discussed. We find that the first of these already provides strong constraints on the underlying theory. It is emphasized more generally that time (and space) variations of fundamental couplings and their correlations may be a significant probe of ultra-high-energy physics.Comment: 13 pages, uses JHEP.cl

    Neutron-Electron EDM Correlations in Supersymmetry and Prospects for EDM Searches

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    Motivated by recent progress in experimental techniques of electric dipole moment (EDM) measurements, we study correlations between the neutron and electron EDMs in common supersymmetric models. These include minimal supergravity (mSUGRA) with small CP phases, mSUGRA with a heavy SUSY spectrum, the decoupling scenario and split SUSY. In most cases, the electron and neutron EDMs are found to be observable in the next round of EDM experiments. They exhibit certain correlation patterns. For example, if d_n ~ 10^{-27} e cm is found, d_e is predicted to lie in the range 10^{-28}-10^{-29} e cm.Comment: 16 pages,12 figures. To appear in JHEP. A note on stability of the correlations added in Conclusions; refs. and footnotes adde

    Indirect Signs of the Peccei-Quinn Mechanism

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    In the Standard Model, the renormalization of the QCD vacuum angle θ\theta is extremely tiny, and small θ\theta is technically natural. In the general Standard Model effective field theory (SMEFT), however, Δθ\Delta\theta is quadratically divergent, reflecting the fact that new sources of hadronic CP-violation typically produce O(1)\mathcal O(1) threshold corrections to θ\theta. The observation of such CP-violating interactions would therefore be in tension with solutions to the strong CP problem in which θ=0\theta=0 is an ultraviolet boundary condition, pointing to the Peccei-Quinn mechanism as the explanation for why θ\theta is small in the infrared. We study the quadratic divergences in θ\theta arising from dimension-6 SMEFT operators and discuss the discovery prospects for these operators at electric dipole moment experiments, the LHC, and future proton-proton colliders.Comment: 27 pages, 3 figures. Comments welcome

    Random Matrix Theories in Quantum Physics: Common Concepts

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    We review the development of random-matrix theory (RMT) during the last decade. We emphasize both the theoretical aspects, and the application of the theory to a number of fields. These comprise chaotic and disordered systems, the localization problem, many-body quantum systems, the Calogero-Sutherland model, chiral symmetry breaking in QCD, and quantum gravity in two dimensions. The review is preceded by a brief historical survey of the developments of RMT and of localization theory since their inception. We emphasize the concepts common to the above-mentioned fields as well as the great diversity of RMT. In view of the universality of RMT, we suggest that the current development signals the emergence of a new "statistical mechanics": Stochasticity and general symmetry requirements lead to universal laws not based on dynamical principles.Comment: 178 pages, Revtex, 45 figures, submitted to Physics Report

    Grand unified theory constrained supersymmetry and neutrinoless double beta decay

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    We analyze the contributions to the neutrinoless double β\beta decay (0νββ0\nu\beta\beta-decay) coming from the Grand Unified Theory (GUT) constrained Minimal Supersymmetric Standard Model (MSSM) with trilinear R-parity breaking. We discuss the importance of two-nucleon and pion-exchange realizations of the quark-level 0νββ0\nu\beta\beta-decay transitions. In this context, the questions of reliability of the calculated relevant nuclear matrix elements within the Renormalized Quasiparticle Random Phase Approximation (pn-RQRPA) for several medium and heavy open-shell nuclei are addressed. The importance of gluino and neutralino contributions to 0νββ0\nu\beta\beta-decay is also analyzed. We review the present experiments and deduce limits on the trilinear R-parity breaking parameter λ111\lambda_{111}' from the non-observability of 0νββ0\nu\beta\beta-decay for different GUT constrained SUSY scenarios. In addition, a detailed study of limits on the MSSM parameter space coming from the BXsγB \to X_s \gamma processes by using the recent CLEO and OPAL results is performed. Some studies in respect to the future 0νββ0\nu\beta\beta-decay project GENIUS are also presented.Comment: 29 pages, 8 figure
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