452 research outputs found

    Ό\mu-term as the origin of baryon and lepton number asymmetry

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    We study a possibility of combining an origin of the Ό\mu-term and the baryon and lepton number asymmetry. If we assume that the Ό\mu-term is generated through a flat direction of a singlet scalar field, the coherent oscillation of this condensate around its potential minimum can store the global U(1) charge asymmetry. The decay of this condensate can distribute this asymmetry into the lepton and baryon number asymmetry as far as its decay occurs at an appropriate temperature. We examine the compatibility between this scenario and the small neutrino mass generation based on both the ordinary seesaw mechanism and the bilinear R-parity violating terms.Comment: 22 pages, published versio

    Mass bound of the lightest neutral Higgs scalar in the extra U(1) models

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    The upper mass bound of the lightest neutral Higgs scalar is studied in the Ό\mu problem solvable extra U(1) models by using the analysis of the renormalization group equations. In order to restrict the parameter space we take account of a condition of the radiative symmetry breaking and some phenomenological constraints. We compare the bound obtained based on this restricted parameter space with the one of the next to the minimal supersymmetric standard model (NMSSM). Features of the scalar potential and renormalization group equations of the Yukawa couplings among Higgs chiral supermultiplets are rather different between them. They can reflect in this bound.Comment: 22 pages, latex, 11 eps-figure

    The Higgs Sector in a U(1)â€ČU(1)^\prime Extension of the MSSM

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    We consider the Higgs sector in an extension of the MSSM with extra SM singlets, involving an extra U(1)â€ČU(1)^\prime gauge symmetry, in which the domain-wall problem is avoided and the effective ÎŒ\mu parameter is decoupled from the new gauge boson Zâ€ČZ^\prime mass. The model involves a rich Higgs structure very different from that of the MSSM. In particular, there are large mixings between Higgs doublets and the SM singlets, significantly affecting the Higgs spectrum, production cross sections, decay modes, existing exclusion limits, and allowed parameter range. Scalars considerably lighter than the LEP2 bound (114 GeV) are allowed, and the range tan⁥ÎČ∌1\tan \beta \sim 1 is both allowed and theoretically favored. Phenomenologically, we concentrate our study on the lighter (least model-dependent, yet characteristic) Higgs particles with significant SU(2)-doublet components to their wave functions, for the case of no explicit CP violation in the Higgs sector. We consider their spectra, including the dominant radiative corrections to their masses from the top/stop loop. We computed their production cross sections and reexamine the existing exclusion limits at LEP2. We outline the searching strategy for some representative scenarios at a future linear collider. We emphasize that gaugino, Higgsino, and singlino decay modes are indicative of extended models and have been given little attention. We present a comprehensive list of model scenarios in the Appendices.Comment: 49 pages, 17 figure

    Suppressing the Ό\mu and neutrino masses by a superconformal force

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    The idea of Nelson and Strassler to obtain a power law suppression of parameters by a superconformal force is applied to understand the smallness of the Ό\mu parameter and neutrino masses in R-parity violating supersymmetric standard models. We find that the low-energy sector should contain at least another pair of Higgs doublets, and that a suppression of \lsim O(10^{-13}) for the Ό\mu parameter and neutrino masses can be achieved generically. The superpotential of the low-energy sector happens to possess an anomaly-free discrete R-symmetry, either R3R_3 or R6R_6, which naturally suppresses certain lepton-flavor violating processes, the neutrinoless double beta decays and also the electron electric dipole moment. We expect that the escape energy of the superconformal sector is \lsim O(10) TeV so that this sector will be observable at LHC. Our models can accommodate to a large mixing among neutrinos and give the same upper bound of the lightest Higgs mass as the minimal supersymmetric standard model.Comment: 24 page

    Collective Motion and Phase Transitions of Symmetric Camphor Boats

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    The motion of several self-propelled boats in a narrow channel displays spontaneous pattern formation and kinetic phase transitions. In contrast with previous studies on self-propelled particles, this model does not require stochastic fluctuations and it is experimentally accessible. By varying the viscosity in the system, it is possible to form either a stationary state, correlated or uncorrelated oscillations, or unidirectional flow. Here, we describe and analyze these self organized patterns and their transitions.Comment: 6 pages, 6 figure

    Sfermion masses in Nelson-Strassler type of models: SUSY standard models coupled with SCFTs

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    We study soft SUSY breaking parameters in the Nelson-Strassler type of models: SUSY standard models coupled with SCFTs. In this type of models, soft SUSY breaking parameters including sfermion masses can be suppressed around the decoupling scale of SCFTs. We clarify the condition to derive exponential suppression of sfermion masses within the framework of pure SCFTs. Such behavior is favorable for degeneracy of sfermion masses. However, the realistic sfermion masses are not quite degenerate due to the gauge couplings and the gaugino masses in the SM sector. We show the sfermion mass spectrum obtained in such models. The aspect of suppression for the soft SUSY breaking parameters is also demonstrated in an explicit model. We also give a mechanism generating the Ό\mu-term of the Electro-Weak scale by a singlet field coupled with the SCFT.Comment: 28 pages, 8 figures, LaTeX file; corrected typos and references adde

    The Quiet-Sun Photosphere and Chromosphere

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    The overall structure and the fine structure of the solar photosphere outside active regions are largely understood, except possibly important roles of a turbulent near-surface dynamo at its bottom, internal gravity waves at its top, and small-scale vorticity. Classical 1D static radiation-escape modelling has been replaced by 3D time-dependent MHD simulations that come closer to reality. The solar chromosphere, in contrast, remains ill-understood although its pivotal role in coronal mass and energy loading makes it a principal research area. Its fine structure defines its overall structure, so that hard-to-observe and hard-to-model small-scale dynamical processes are the key to understanding. However, both chromospheric observation and chromospheric simulation presently mature towards the required sophistication. The open-field features seem of greater interest than the easier-to-see closed-field features.Comment: Accepted for special issue "Astrophysical Processes on the Sun" of Phil. Trans. Royal Soc. A, ed. C. Parnell. Note: clicking on the year in a citation opens the corresponding ADS abstract page in the browse

    Acoustic Events in the Solar Atmosphere from Hinode/SOT NFI observations

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    We investigate the properties of acoustic events (AEs), defined as spatially concentrated and short duration energy flux, in the quiet sun using observations of a 2D field of view (FOV) with high spatial and temporal resolution provided by the Solar Optical Telescope (SOT) onboard \textit{Hinode}. Line profiles of Fe \textsc{i} 557.6 nm were recorded by the Narrow band Filter Imager (NFI) on a 82"×82"82" \times 82" FOV during 75 min with a time step of 28.75 s and 0.08"" pixel size. Vertical velocities were computed at three atmospheric levels (80, 130 and 180 km) using the bisector technique allowing the determination of energy flux in the range 3-10 mHz using two complementary methods (Hilbert transform and Fourier power spectra). Horizontal velocities were computed using local correlation tracking (LCT) of continuum intensities providing divergences. The net energy flux is upward. In the range 3-10 mHz, a full FOV space and time averaged flux of 2700 W m−2^{-2} (lower layer 80-130 km) and 2000 W m−2^{-2} (upper layer 130-180 km) is concentrated in less than 1% of the solar surface in the form of narrow (0.3"") AE. Their total duration (including rise and decay) is of the order of 10310^{3} s. Inside each AE, the mean flux is 1.61051.6 10^{5} W m−2^{-2} (lower layer) and 1.21051.2 10^{5} W m−2^{-2} (upper). Each event carries an average energy (flux integrated over space and time) of 2.510192.5 10^{19} J (lower layer) to 1.910191.9 10^{19} J (upper). More than 10610^{6} events could exist permanently on the Sun, with a birth and decay rate of 3500 s−1^{-1}. Most events occur in intergranular lanes, downward velocity regions, and areas of converging motions.Comment: 18 pages, 10 figure

    A Statistical Inference Method for Interpreting the CLASP Observations

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    On 3rd September 2015, the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) successfully measured the linear polarization produced by scattering processes in the hydrogen Lyman-α\alpha line of the solar disk radiation, revealing conspicuous spatial variations in the Q/IQ/I and U/IU/I signals. Via the Hanle effect the line-center Q/IQ/I and U/IU/I amplitudes encode information on the magnetic field of the chromosphere-corona transition region (TR), but they are also sensitive to the three-dimensional structure of this corrugated interface region. With the help of a simple line formation model, here we propose a statistical inference method for interpreting the Lyman-α\alpha line-center polarization observed by CLASP.Comment: Accepted for publication in The Astrophysical Journa
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