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Flavor and CP conserving moduli mediated SUSY breaking in flux compactification
Choi, Kiwoon,Jeong, Kwang Sik,Okumura, Ken-Ichi IOP Publishing Ltd 2008 Journal of high energy physics Vol.2008 No.7
In certain class of flux compactification, moduli mediated supersymmetry (SUSY) breaking preserves flavor and CP at leading order in the perturbative expansion controlled by the vacuum expectation value of the messenger modulus. Nevertheless there still might be dangerous flavor or CP violation induced by higher order Kähler potential. We examine the constraints on such SUSY breaking scheme imposed by low energy flavor and/or CP violating observables. It is found that all phenomenological constraints can be satisfied even for generic form of higher order Kähler potential and sparticle spectra in the sub-TeV range, under plausible assumptions on the size of higher order correction and flavor mixing angles. This implies for instance that mirage mediation scheme of SUSY breaking, which involves such modulus mediation together with an anomaly mediation of comparable size, and also the modulus-dominated mediation realized in flux compactification can be free from the SUSY flavor and CP problems, while giving gaugino and sfermion masses in the sub-TeV range.
Transition from Nanorod to Nanotube of Poly(vinylidene trifluoroethylene) Ferroelectric Nanofiber
Choi, Kiwoon,Lee, Se Cheol,Liang, Yongri,Kim, Kap Jin,Lee, Han Sup American Chemical Society 2013 Macromolecules Vol.46 No.8
<P>The nanorod-to-nanotube transition of a piezoelectric poly(vinylidenefluoride-<I>co</I>-trifluoroethylene) (P(VDF-TrFE)) nanofiber inside cylindrical nanopores (CNP) with various pore diameters was precisely determined. After infiltrating the polymer into the CNP, a solid nanorod or hollow nanotube was obtained depending on the relative magnitude of the CNP diameter used compared to the critical pore diameter. The thickness of the lamellae formed inside the solid nanorod was found to be linearly dependent on the diameter of the nanocylinder. In addition, the wall thickness of the polymer nanotube increased with increasing nanocylinder diameter. The dependence of ferroelectric properties of the P(VDF–TrFE) nanofiber on the morphological transition were evaluated by measuring the piezoelectric polarization hysteresis loops. Compared to the hollow nanotube, the solid P(VDF–TrFE) nanorod showed significantly enhanced maximum polarization behavior, which is desirable for ferroelectric applications. These results show that the morphological transition from solid nanorod to hollow nanotube can play an important key role in the ferroelectric device fabrication of P(VDF–TrFE).</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2013/mamobx.2013.46.issue-8/ma302679g/production/images/medium/ma-2012-02679g_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ma302679g'>ACS Electronic Supporting Info</A></P>
Little SUSY hierarchy in mixed modulus-anomaly mediation
Choi, Kiwoon,Jeong, Kwang Sik,Kobayashi, Tatsuo,Okumura, Ken-ichi North-Holland Pub. Co 2006 Physics letters. Section B Vol.633 No.2-3
<P><B>Abstract</B></P><P>Motivated by the KKLT string compactification involving a supersymmetry-breaking uplifting potential, we examine 4D effective supergravity with a generic form of uplifting potential, focusing on the possibility that the resulting mixed modulus-anomaly mediated soft terms realize the little hierarchy between the Higgs boson masses <SUB>mH</SUB> and the sparticle masses <SUB>mSUSY</SUB>. It is noted that for some type of uplifting potential, the anomaly-mediated contribution to mH2 at <SUB>MGUT</SUB> can cancel the subsequent renormalization group evolution of mH2 down to TeV scale, thereby the model can naturally realize the little hierarchy mH2∼mSUSY2/8<SUP>π2</SUP> which is desirable for the lightest Higgs boson mass to satisfy the experimental bound. In such models, the other Higgs mass parameters <I>μ</I> and <I>B</I> can have the desirable size μ∼B∼<SUB>mH</SUB> without severe fine-tuning of parameters, although the gravitino is much heavier than the Higgs boson. Those models for the little hierarchy avoid naturally the dangerous SUSY flavor and CP violations, and predict nearly degenerate low energy gaugino masses, pure Higgsino LSP, and also a specific relation between the stop and gaugino masses.</P>
Supersymmetry breaking andmoduli stabilization with anomalous U(1) gauge symmetry
Choi, Kiwoon,Jeong, Kwang-Sik Institute of Physics Pub 2006 The journal of high energy physics Vol.2006 No.8
We examine the effects of anomalous U(1)<SUB><I>A</I></SUB> gauge symmetry on soft supersymmetry breaking terms while incorporating the stabilization of the modulus-axion multiplet responsible for the Green-Schwarz (GS) anomaly cancellation mechanism. In case of the KKLT stabilization of the GS modulus, soft terms are determined by the GS modulus mediation, the anomaly mediation and the U(1)<SUB><I>A</I></SUB> mediation which are generically comparable to each other, thereby yielding the mirage mediation pattern of superparticle masses at low energy scale. Independently of the mechanism of moduli stabilization and supersymmetry breaking, the U(1)<SUB><I>A</I></SUB> <I>D</I>-term potential can not be an uplifting potential for de Sitter vacuum when the gravitino mass is smaller than the Planck scale by many orders of magnitude. We also discuss some features of the supersymmetry breaking by red-shifted anti-brane which is a key element of the KKLT moduli stabilization.
Sparticle masses in deflected mirage mediation
Choi, Kiwoon,Jeong, Kwang Sik,Nakamura, Shuntaro,Okumura, Ken-Ichi,Yamaguchi, Masahiro IOP Publishing Ltd 2009 Journal of high energy physics Vol.2009 No.4
We discuss the sparticle mass patterns that can be realized in deflected mirage mediation scenario of supersymmetry breaking, in which the moduli, anomaly, and gauge mediations all contribute to the MSSM soft parameters. Analytic expression of low energy soft parameters and also the sfermion mass sum rules are derived, which can be used to interpret the experimentally measured sparticle masses within the framework of the most general mixed moduli-gauge-anomaly mediation. Phenomenological aspects of some specific examples are also discussed.