Xi hypernuclear spectroscopy with SKS+ spectrometer at J-PARC

title: Search for $^6_\Lambda$H hypernucleus by the $^6$Li$(\pi^-,K^+)$ reaction at $p_{\pi^-}$ = 1.2 GeV/$c$
abstract: We have carried out an experiment to search for a neutron-ric h hypernucleus, 6 Λ H, by the6Li(π−,K+) reaction atpπ− =1.2 GeV/c. The obtained missing-mass spectrum with an estimated energy re solution of 3.2 MeV (FWHM) showed no peak structure correspo nding to the6 Λ H hypernucleus neither below nor above the 4 Λ H+2n particle decay threshold. An upper limit of the production c ross section for the bound6 Λ H hypernucleus was estimated to be 1.2 nb /sr at 90% confidence level.

title: High-resolution search for the Theta(+) pentaquark via a pion-induced reaction at J-PARC
abstract: The pentaquark Theta(+) has been searched for via the pi(-) p --> K- X reaction with beam momenta of 1.92 and 2.01 GeV/c at J-PARC. A missing mass resolution of 2 MeV (FWHM) was achieved but no sharp peak structure was observed. The upper limits on the production cross section averaged over the scattering angle from 2 degrees to 15 degrees in the laboratory frame were found to be less than 0.28 mu b/sr at the 90% confidence level for both the 1.92- and 2.01- GeV/c data. The systematic uncertainty of the upper limits was controlled within 10%. Constraints on the Theta(+) decay width were also evaluated with a theoretical calculation using an effective Lagrangian. The present result implies that the width should be less than 0.36 and 1.9 MeV for the spin-parity of 1/2(+) and 1/2(-), respectively

title: Effects of cosmological moduli fields on cosmic microwave background
abstract: We discuss effects of cosmological moduli fields on the cosmic microwave background (CMB). If a modulus field φ once dominates the universe, the CMB we observe today is from the decay of φ and its anisotropy is affected by the primordial fluctuation in the amplitude of the modulus field. Consequently, constraints on the inflaton potential from the CMB anisotropy can be relaxed. In particular, the scale of the inflation may be significantly lowered. In addition, with the cosmological moduli fields, correlated mixture of adiabatic and isocurvature fluctuations may be generated, which results in enhanced CMB angular power spectrum at higher multipoles relative to that of lower ones. Such an enhancement can be an evidence of the cosmological moduli fields, and may be observed in future satellite experiments.

title: Duality of a supersymmetric model with the Pati-Salam group
abstract: Recently one of the authors proposed a dual theory of a Supersymmetric Standard Model (SSM), in which it is naturally understood that at least one quark (the top quark) should be heavy, i.e., almost the same order as the weak scale, and the supersymmetric Higgs mass parameter $\mu$ can naturally be expected to be small. However, the model cannot have Yukawa couplings of the lepton sector. In this paper, we examine a dual theory of a Supersymmetric Model with the Pati-Salam gauge group $SU(4)_{PS}\times SU(2)_L\times SU(2)_R $ with respect to the gauge group $SU(4)_{PS}$. In this scenario, Yukawa couplings of the lepton sector can be induced. In this model the Pati-Salam breaking scale should be around the SUSY breaking scale.

title: Density perturbations from modulated decay of the curvaton
abstract: We study density perturbations, including their non-Gaussianity, in models in which the decay rate of the curvaton depends on another light scalar field, denoted the modulaton. Although this model shares some similarities with the standard curvaton and modulated reheating scenarios, it exhibits interesting predictions for fNL and gNL that are specific to this model. We also discuss the possibility that both modulaton and curvaton fluctuations contribute to the final curvature perturbation. Our results naturally include the standard curvaton and modulated reheating scenarios as specific limits and are thus useful to present a unified treatment of these models and their variants.

title: Isocurvature fluctuations in tracker quintessence models
abstract: We consider effects of the isocurvature perturbation in the framework of the tracker-type quintessence models. During the inflation, fluctuations in the amplitude of the quintessence field are generated, which provide isocurvature component of the cosmic density perturbation. Contrary to the conventional notion, it is shown that effects of the isocurvature fluctuation may become sizable in some cases, and in particular, the cosmic microwave background angular power spectrum may be significantly enhanced due to the effect of the isocurvature mode. Such an enhancement may be detectable in on-going and future experiments.

title: The ASTRO-H X-ray Observatory
abstract: The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3–12 keV with high spectral resolution of ΔE ≦ 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5–80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4–12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40–600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.