Suppression of the neutralino relic density with supersymmetric CP violation

We study pair annihilations of the neutralino dark matter in the minimal supersymmetric standard model with CP violation. We consider the case that the higgsino mass and the trilinear scalar couplings have CP-violating phases of order unity, taking a scenario that the scalar fermions in the first two generations are much heavier than those in the third generation to avoid a severe constraint from experimental limits on electric dipole moments. It is found that, when the lightest neutralino ($\chi$) is bino-like, the cross sections of the $W$-boson pair production $\chi\chi$ $\to$ $W^+W^-$ and the lightest Higgs boson pair production $\chi\chi$ $\to$ $H^0_2 H^0_2$ for nonrelativistic neutralinos can be significantly enhanced by the phase of the higgsino mass. The relic density of the neutralino can be considerably suppressed by this effect. However, even this suppression is not enough to make bino-like dark matter consistent with a cosmological constraint. We also discuss the effect of CP violation on the positron flux from neutralino pair annihilations in the galactic halo.Comment: 37 pages, 16 figures. Numerical erros are corrected in the new versio

Anomaly of discrete family symmetries and gauge coupling unification

Anomaly of discrete symmetries can be defined as the Jacobian of the path-integral measure. We assume that an anomalous discrete symmetry at low energy is remnant of an anomaly free discrete symmetry, and that its anomaly is cancelled by the Green-Schwarz(GS) mechanism at a more fundamental scale. If the Kac-Moody levels k_i assume non-trivial values, the GS cancellation conditions of anomaly modify the ordinary unification of gauge couplings. This is most welcome, because for a renormalizable model to be realistic any non-abelian family symmetry, which should not be hardly broken low-energy, requires multi SU(2)_L doublet Higgs fields. As an example we consider a recently proposed supersymmetric model with Q_6 family symmetry. In this example, k_2=1, k_3=3 satisfies the GS conditions and the gauge coupling unification appears close to the Planck scale.Comment: Talk given at the Summer Institute 2006 (SI2006), APCTP, Pohang, Korea. 23-30 Aug 200

The K-theoretical range of Cuntz-Krieger algebras

We augment Restorff's classification of purely infinite Cuntz-Krieger algebras by describing the range of his invariant on purely infinite Cuntz-Krieger algebras. We also describe its range on purely infinite graph C*-algebras with finitely many ideals, and provide 'unital' range results for purely infinite Cuntz-Krieger algebras and unital purely infinite graph C*-algebras.Comment: 16 pages. This article contains material that was originally contained arXiv:1301.7223v1. v2: minor changes, v3: minor changes, final versio

Nucleus from String Theory

In generic holographic QCD, we find that baryons are bound to form a nucleus, and that its radius obeys the empirically-known mass number (A) dependence r A^{1/3} for large A. Our result is robust, since we use only a generic property of D-brane actions in string theory. We also show that nucleons are bound completely in a finite volume. Furthermore, employing a concrete holographic model (derived by Hashimoto, Iizuka, and Yi, describing a multi-baryon system in the Sakai-Sugimoto model), the nuclear radius is evaluated as O(1) x A^{1/3} [fm], which is consistent with experiments.Comment: 4 pages; Ver.2: terminology on nuclear density saturation modified, a reference adde

Factors Associated with Choking During Meals; a Risk Indicator for Repetitive Fevers in the Elderly Community

Background: Choking during meals is a common symptom in the elderly, however the factors associated with it have not been fully clarified. In this study, we examined the factors associated with choking during meals. Methods: The oral health status and practices that promote oral health conditions was surveyed in 1305 community dwelling elderly using a self-administered questionnaire. Eight items including satisfaction with their oral condition, denture fit, chewing ability, tooth brushing frequency, dental visits, exercises to train muscles for chewing and swallowing, choking during meals, and repetitive fever were selected for analysis. Results: 25.1% of the subjects experienced choking during meals, which was significantly associated with repetitive fever occurrence. Differences in satisfaction levels with their oral condition, denture fit, chewing ability, and tooth brushing frequency were observed between groups with and without choking. Age, satisfaction level, and chewing ability were significantly associated with choking during meals. Conclusions: This study demonstrated that choking during meals is a risk indicator for repetitive fever in the elderly living in community settings. Poor chewing ability and dissatisfaction with their oral condition were risk factors associated with choking. These results suggest that training the elderly to eat efficiently and safely and improving oral conditions is necessary for those who suffer from choking during meals to prevent repetitive fever. &nbsp

Light wino dark matter in brane world cosmology

The thermal relic density of the wino-like neutralino dark matter in the brane world cosmology is studied. The expansion law at a high energy regime in the brane world cosmology is modified from the one in the standard cosmology, and the resultant relic density can be enhanced if the five dimensional Planck mass $M_5$ is low enough. We calculate the wino-like neutralino relic density in the anomaly mediated supersymmetry breaking scenario and show that the allowed region is dramatically modified from the one in the standard cosmology and the wino-like neutralino with mass of order 100 GeV can be a good candidate for the dark matter. Since the allowed region disappears eventually as $M_5$ is decreasing, we can find a lower bound on $M_5 \gtrsim 100$ TeV according to the neutralino dark matter hypothesis, namely the lower bound in order for the allowed region of the neutralino dark matter to exist.Comment: 16 pages, 9 figures, final versio

Neutralino dark matter in brane world cosmology

The thermal relic density of the neutralino dark matter in the brane world cosmology is studied. Since the expansion law at a high energy regime in the brane world cosmology is modified from the one in the standard cosmology, the resultant relic density can be altered. It has been found that, if the five dimensional Planck mass $M_5$ is lower than $10^4$ TeV, the brane world cosmological effect is significant at the decoupling time and the resultant relic density is enhanced. We calculate the neutralino relic density in the Constrained Minimal Supersymmetric Standard Model (CMSSM) and show that the allowed region is dramatically modified from the one in the standard cosmology and eventually disappears as $M_5$ is decreasing. We also find a new lower bound on $M_5 \gtrsim 600$ TeV based on the neutralino dark matter hypothesis, namely the lower bound in order for the allowed region of the neutralino dark matter to exist.Comment: 12 pages, 8 figure

Weak Lensing of Galaxy Clusters in MOND

We study weak gravitational lensing of galaxy clusters in terms of the MOND (MOdified Newtonian Dynamics) theory. We calculate shears and convergences of background galaxies for three clusters (A1689, CL0024+1654, CL1358+6245) and the mean profile of 42 SDSS (Sloan Digital Sky Survey) clusters and compare them with observational data. The mass profile is modeled as a sum of X-ray gas, galaxies and dark halo. For the shear as a function of the angular radius, MOND predicts a shallower slope than the data irrespective of the critical acceleration parameter $g_0$. The dark halo is necessary to explain the data for any $g_0$ and for three interpolation functions. If the dark halo is composed of massive neutrinos, its mass should be heavier than 2 eV. However the constraint still depends on the dark halo model and there are systematic uncertainties, and hence the more careful study is necessary to put a stringent constraint.Comment: 12 pages, 7 figures, references added, minor changes, accepted for publication in Ap

Discharge Patterns of Single Fibers in the Cat's Auditory Nerve

Discharge patterns of single fibers in cat auditory nerve in response to controlled acoustic stimul

Ferroelectric Phase Transitions in Ultra-thin Films of BaTiO3

We present molecular dynamics simulations of a realistic model of an ultrathin film of BaTiO$_3$ sandwiched between short-circuited electrodes to determine and understand effects of film thickness, epitaxial strain and the nature of electrodes on its ferroelectric phase transitions as a function of temperature. We determine a full epitaxial strain-temperature phase diagram in the presence of perfect electrodes. Even with the vanishing depolarization field, we find that ferroelectric phase transitions to states with in-plane and out-of-plane components of polarization exhibit dependence on thickness; it arises from the interactions of local dipoles with their electrostatic images in the presence of electrodes. Secondly, in the presence of relatively bad metal electrodes which only partly compensate the surface charges and depolarization field, a qualitatively different phase with stripe-like domains is stabilized at low temperature