1,806 research outputs found

    Pionic BEC--BCS crossover at finite isospin chemical potential

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    We study the character change of the pionic condensation at finite isospin chemical potential \mu_\mathrm{I} by adopting the linear sigma model as a non-local interaction between quarks. At low |\mu_\mathrm{I}| the condensation is purely bosonic, then the Cooper pairing around the Fermi surface grows gradually as |\mu_\mathrm{I}| increases. This q-\bar q pairing is weakly coupled in comparison with the case of the q-q pairing that leads to color superconductivity.Comment: 17 pages, 3 figures, typos in eq.(6) and refs.[37] and [41] are corrected, published in Phys. Rev.

    High-K Precession modes: Axially symmetric limit of wobbling motion

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    The rotational band built on the high-K multi-quasiparticle state can be interpreted as a multi-phonon band of the precession mode, which represents the precessional rotation about the axis perpendicular to the direction of the intrinsic angular momentum. By using the axially symmetric limit of the random-phase-approximation (RPA) formalism developed for the nuclear wobbling motion, we study the properties of the precession modes in 178^{178}W; the excitation energies, B(E2) and B(M1) values. We show that the excitations of such a specific type of rotation can be well described by the RPA formalism, which gives a new insight to understand the wobbling motion in the triaxial superdeformed nuclei from a microscopic view point.Comment: 14 pages, 8 figures (Spelling of the authors name was wrong at the first upload, so it is corrected

    Wobbling Motion in Atomic Nuclei with Positive-Gamma Shapes

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    The three moments of inertia associated with the wobbling mode built on the superdeformed states in 163Lu are investigated by means of the cranked shell model plus random phase approximation to the configuration with an aligned quasiparticle. The result indicates that it is crucial to take into account the direct contribution to the moments of inertia from the aligned quasiparticle so as to realize J_x > J_y in positive-gamma shapes. Quenching of the pairing gap cooperates with the alignment effect. The peculiarity of the recently observed 163Lu data is discussed by calculating not only the electromagnetic properties but also the excitation spectra.Comment: 11 pages, 6 figure

    Parametrizations of triaxial deformation and E2 transitions of the wobbling band

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    By the very definition the triaxial deformation parameter γ\gamma is related to the expectation values of the K=0 and K=2 components of the intrinsic quadrupole tensor operator. On the other hand, using the same symbol "γ\gamma", various different parametrizations of triaxial deformation have been employed, which are suitable for various types of the mean-field potentials. It is pointed out that the values of various "γ\gamma" are quite different for the same actual triaxial deformation, especially for the large deformation; for example, the difference can be almost a factor two for the case of the triaxial superdeformed bands recently observed in the Hf and Lu nuclei. In our previous work, we have studied the wobbling band in Lu nuclei by using the microscopic framework of the cranked Nilsson mean-field and the random phase approximation, where the most serious problem is that the calculated B(E2) value is about factor two smaller. It is shown that the origin of this underestimation can be mainly attributed to the small triaxial deformation; if is used the same triaxial deformation as in the analysis of the particle-rotor model, the calculated B(E2) increases and gives correct magnitude compared with the experimental data.Comment: 10 pages, 9 figure

    One-Loop Corrections to the S and T Parameters in a Three Site Higgsless Model

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    In this paper we compute the the one-loop chiral logarithmic corrections to the S and T parameters in a highly deconstructed Higgsless model with only three sites. In addition to the electroweak gauge bosons, this model contains a single extra triplet of vector states (which we denote \rho^{\pm} and \rho^0), rather than an infinite tower of "KK" modes. We compute the corrections to S and T in 'tHooft-Feynman gauge, including the ghost, unphysical Goldstone-boson, and appropriate "pinch" contributions required to obtain gauge-invariant results for the one-loop self-energy functions. We demonstrate that the chiral-logarithmic corrections naturally separate into two parts, a model-independent part arising from scaling below the \rho mass, which has the same form as the large Higgs-mass dependence of the S or T parameter in the standard model, and a second model-dependent contribution arising from scaling between the \rho mass and the cutoff of the model. The form of the universal part of the one-loop result allows us to correctly interpret the phenomenologically derived limits on the S and T parameters (which depend on a "reference" Higgs-boson mass) in this three-site Higgsless model. Higgsless models may be viewed as dual to models of dynamical symmetry breaking akin to "walking technicolor", and in these terms our calculation is the first to compute the subleading 1/N corrections to the S and T parameters. We also discuss the reduction of the model to the ``two-site'' model, which is the usual electroweak chiral lagrangian, noting the ``non-decoupling'' contributions present in the limit as M_\rho goes to infinity.Comment: 58 pages; uses JHEP and axodraw. Extensively corrected to incorporate consistent perturbative expansion, additional pinch contributions, and running of delocalization parameter. Footnotes adde

    A Solution for Little Hierarchy Problem and b --> s gamma

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    We show that all the parameters which destabilize the weak scale can be taken around the weak scale in the MSSM without conflicting with the SM Higgs mass bound set by LEP experiment. The essential point is that if the lightest CP-even Higgs h in the MSSM has only a small coupling to Z boson, g_{ZZh}, LEP cannot generate the Higgs sufficiently. In the scenario, the SM Higgs mass bound constrains the mass of the heaviest CP-even Higgs H which has the SM like g_{ZZH} coupling. However, it is easier to make the heaviest Higgs heavy by the effect of off-diagonal elements of the mass matrix of the CP-even Higgs because the larger eigenvalue of 2 times 2 matrix becomes larger by introducing off-diagonal elements. Thus, the smaller stop masses can be consistent with the LEP constraints. Moreover, the two excesses observed at LEP Higgs search can naturally be explained as the signals of the MSSM Higgs h and H in this scenario. One of the most interesting results in the scenario is that all the Higgs in the MSSM have the weak scale masses. For example, the charged Higgs mass should be around 130 GeV. This looks inconsistent with the lower bound obtained by the b --> s gamma process as m_{H^\pm}>350GeV. However, we show that the amplitude induced by the charged Higgs can naturally be compensated by that of the chargino if we take the mass parameters by which the little hierarchy problem can be solved. The point is that the both amplitudes have the same order of magnitudes when all the fields in the both loops have the same order of masses.Comment: 14 pages, 5 figures, input parameter slightly changed, figures replaced, references correcte

    AKARI-CAS --- Online Service for AKARI All-Sky Catalogues

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    The AKARI All-Sky Catalogues are an important infrared astronomical database for next-generation astronomy that take over the IRAS catalog. We have developed an online service, AKARI Catalogue Archive Server (AKARI-CAS), for astronomers. The service includes useful and attractive search tools and visual tools. One of the new features of AKARI-CAS is cached SIMBAD/NED entries, which can match AKARI catalogs with other catalogs stored in SIMBAD or NED. To allow advanced queries to the databases, direct input of SQL is also supported. In those queries, fast dynamic cross-identification between registered catalogs is a remarkable feature. In addition, multiwavelength quick-look images are displayed in the visualization tools, which will increase the value of the service. In the construction of our service, we considered a wide variety of astronomers' requirements. As a result of our discussion, we concluded that supporting users' SQL submissions is the best solution for the requirements. Therefore, we implemented an RDBMS layer so that it covered important facilities including the whole processing of tables. We found that PostgreSQL is the best open-source RDBMS products for such purpose, and we wrote codes for both simple and advanced searches into the SQL stored functions. To implement such stored functions for fast radial search and cross-identification with minimum cost, we applied a simple technique that is not based on dividing celestial sphere such as HTM or HEALPix. In contrast, the Web application layer became compact, and was written in simple procedural PHP codes. In total, our system realizes cost-effective maintenance and enhancements.Comment: Yamauchi, C. et al. 2011, PASP..123..852

    Quasiparticles and Energy Scaling in Bi2_2Sr2_2Can−1_{n-1}Cun_nO2n+4_{2n+4} (n\it{n}=1-3): Angle-Resolved Photoemission Spectroscopy

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    Angle-resolved photoemission spectroscopy (ARPES) has been performed on the single- to triple-layered Bi-family high-{\it Tc_c} superconductors (Bi2_2Sr2_2Can−1_{n-1}Cun_nO2n+4_{2n+4}, n\it{n}=1-3). We found a sharp quasiparticle peak as well as a pseudogap at the Fermi level in the triple-layered compound. Comparison among three compounds has revealed a universal rule that the characteristic energies of superconducting and pseudogap behaviors are scaled with the maximum {\it Tc_c}.Comment: 4 pages, 4 figure

    An ocean–ice coupled response during the last glacial: a view from a marine isotopic stage 3 record south of the Faeroe Shetland Gateway

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    150 μm) lithic fraction (grain concentration) and the analysis of selected biogenic proxies (assemblages and stable isotope ratio of calcareous planktonic foraminifera, dinoflagellate cyst – e.g. dinocyst – assemblages). Results presented here are focussed on the dinocyst response, this proxy providing the reconstruction of past sea-surface hydrological conditions, qualitatively as well as quantitatively (e.g. transfer function sensu lato). Our study documents a very coherent and sensitive oceanic response to the MIS3 rapid climatic variability: strong fluctuations, matching those of stadial/interstadial climatic oscillations as depicted by Greenland ice cores, are recorded in the MD99-2281 archive. Proxies of terrigeneous and detritical material suggest increases in continental advection during Greenland Stadials (including Heinrich events), the latter corresponding also to southward migrations of polar waters. At the opposite, milder sea-surface conditions seem to develop during Greenland Interstadials. After 30 ka, reconstructed paleohydrological conditions evidence strong shifts in SST: this increasing variability seems consistent with the hypothesised coalescence of the British and Fennoscandian ice sheets at that time, which could have directly influenced sea-surface environments in the vicinity of core MD99-2281

    Topcrosses in the selection of testers and inbred lines S3 for the yield and bromatological quality of silage maize.

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    The study aiming to evaluate the combining ability of maize partially inbred lines (S3) in crosses with testers ofnarrow genetic base aiming at the selection of the inbred lines, testers and topcross hybrids. Three simple latticetrials with 81 treatments were carried out in the 2014/2015 and 2015/2016 growing seasons. For each growingseason, trials were used to evaluate the topcross hybrids obtained in combination with the testers AG8088,DKB330 (single-cross hybrids) and 9.H33.3 (line). The hybrid AG8088 and line 9.H3.33 were the best testers forgrain yield. The line 9.H3.33 was the best tester for the traits related to yield and quality of silage maize. Theinbred lines that stood out for their combining abilities and capacity of generating great topcross hybrids with thetesters (i.e., 201-23.2, 201-59.1, 201-80.2, 201-81.5, 203-195.3, 201-100.4, 201-145.4, 201-169.3, 202-155, 202-159, 203-23, 203- 31, 203-32, 203-38, 203-75, 203-98, 203-111, 203-135, 203-139, 203-150, 203-188, 203-235,and 203-237) should be maintained in the UEM silage maize breeding program. Progenies 201-59.01, 201-100.4,203-135, 203-150, 203-235 and 203-254 were selected as tester lines of progenies derived from selfing of thetesters AG8088 and DKB330 to improve the silage maize quality. The topcross hybrids 201-95.3 x 9.H3.33, 203-71x 9.H3.33, 203-72 x 9.H3.33, 203-88 x 9.H3.33, 203-139 x 9.H3.33, and 203-150 x 9.H3.33 were selected for goodperformance for agronomic and bromatological silage maize traits. These hybrids are indicated for evaluationsin more environments, with a view to recommending commercial cultivars for grain and silage production in thefuture
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