601 research outputs found

    Physics Prospects --Why Do We Want a Linear Collider?--

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    The need to understand physics of electroweak symmetry breaking is reviewed. An electron positron linear collider will play crucial roles in that respect. It is discussed how the LHC and a linear collider need each other to understand symmetry breaking mechanism unambiguously. Two popular scenarios, supersymmetry and technicolor-like models, are used to demonstrate this point.Comment: 24 pages, 10 embedded Postscript figures, uses psfig.sty and sprocl.sty (World Scientific). Invited talk given at 3rd International Workshop on Physics and Experiments with e+ e- Linear Colliders, Sep 8-12, 1995, Iwate, Japan. Slightly improved from the original manuscript for the proceeding

    Probing Physics at Short Distances with Supersymmetry

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    We discuss the prospect of studying physics at short distances, such as Planck length or GUT scale, using supersymmetry as a probe. Supersymmetry breaking parameters contain information on all physics below the scale where they are induced. We will gain insights into grand unification (or in some cases string theory) and its symmetry breaking pattern combining measurements of gauge coupling constants, gaugino masses and scalar masses. Once the superparticle masses are known, it removes the main uncertainty in the analysis of proton decay, flavor violation and electric dipole moments. We will be able to discuss the consequence of flavor physics at short distances quantitatively.Comment: 20 pages, uses sprocl.sty, psfig.sty, to appear in `Perspectives on Supersymmetry', World Scientific, Editor G. Kan

    Nucleon Decay in GUT and Non-GUT SUSY Models

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    I first emphasize the importance of searching for nucleon decay in the context of supersymmetric models. The status of minimal SUSY SU(5) model is reviewed, which can be definitively ruled out by a combination of superKamiokande and LEP-2 experiments. Non-minimal models may provide some suppression in the nucleon decay rates, but there is still a good chance for superKamiokande. I point out that the operators suppressed even by the Planck-scale are too large. We need a suppression mechanism for the operators at the level of 10−710^{-7}, and the mechanism, I argue, may well be a flavor symmetry. A particular example predicts p→K0e+p \rightarrow K^0 e^+ to be the dominant mode which does not arise in GUT models.Comment: 6 pages, LaTeX, Psfig, talk presented at the International Conference on High Energy Physics, Warsaw, July 26-30, 199

    Technicolorful Supersymmetry

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    Technicolor achieves electroweak symmetry breaking (EWSB) in an elegant and natural way, while it suffers from severe model building difficulties. I propose to abandon its secondary goal to eliminate scalar bosons in exchange of solving numerous problems using supersymmetry. It helps to understand walking dynamics much better with certain exact results. In the particular model presented here, there is no light elementary Higgs boson and the EWSB is fully dynamical, hence explaining the hierarchy; There is no alignment problem and no light pseudo-Nambu-Goldstone bosons exist; The fermion masses are generated by a ultraviolet-complete renormalizable extended technicolor sector with techni-GIM mechanism and hence the sector is safe from flavor-changing-neutral-current constraints; The "e+ e-'' production of techni-states in the superconformal window is calculable; The electroweak precision observables are (un)fortunately not calculable.Comment: 6 pages. Markus Luty pointed out a mistake in the naive dimensional analysis in the first version of the paper. See hep-ph/0006224 for more details. The new version uses superconformal dynamics to enhance the ETC operato

    Impact of Neutrino Oscillation Measurements on Theory

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    Neutrino oscillation data had been a big surprise to theorists, and indeed they have ongoing impact on theory. I review what the impact has been, and what measurements will have critical impact on theory in the future.Comment: 8 pages, uses aipproc, 6 figures. Plenary talk presented at Nufact 03, 5th International Workshop on Neutrino Factories & Superbeams, Columbia University, New York, 5-11 June 200


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    I review phenomenologically interesting aspects of supersymmetry. First I point out that the discovery of the positron can be regarded as a historic analogue to the would-be discovery of supersymmetry. Second I review the recent topics on the unification of the gauge coupling constants, mbm_b--mτm_\tau relation, proton decay, and baryogenesis. I also briefly discuss the recent proposals to solve the problem of flavor changing neutral currents. Finally I argue that the measurements of supersymmetry parameters may probe the physics at the Planck scale.Comment: LBL-36175, LaTeX, 27 pages. Psfig1.9 required. Invited talk presented at the 22nd INS International Symposium on Physics with High Energy Colliders, Tokyo, Japan, March 8--10, 1994, to appear in Proceedings of INS Symposium. The original version submitted in June, only references and spellings corrected. Five EPS figures appended in uuencoded forma

    Theory of Neutrino Masses and Mixings

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    Neutrino physics is going through a revolutionary progress. In this talk I review what we have learned and why neutrino mass is so important. Neutrino masses and mixings are already shedding new insight into the origin of flavor. Given the evidences for neutrino mass, leptogenesis is gaining momentum as the origin of cosmic baryon asymmetry. Best of all, we will learn a lot more in the coming years.Comment: Talk at Lepton Photon 2001. 18 pages, LaTeX2e, uses ws-p10x7.cl