Leptogenesis in models with multi-Higgs bosons

We study the leptogenesis scenario in models with multi-Higgs doublets. It is pointed out that the washing-out process through the effective dimension five interactions, which has not been taken into account seriously in the conventional scenario, can be effective, and the resultant baryon asymmetry can be exponentially suppressed. This fact implies new possible scenario where the observed baryon asymmetry is the remnant of the washed out lepton asymmetry which was originally much larger than the one in the conventional scenario. Our new scenario is applicable to some neutrino mass matrix models which predict too large CP-violating parameter and makes them viable through the washing-out process.Comment: Latex 2e, 11 pages, 2 figures. Many parts in the original manuscript have been revised, but conclusions are unchange

(D* to D + gamma) and (B* to B + gamma) as derived from QCD Sum Rules

The method of QCD sum rules in the presence of the external electromagnetic $F_{\mu\nu}$ field is used to analyze radiative decays of charmed or bottomed mesons such as $D^{\ast}\to D\gamma$ and $B^{\ast}\to B\gamma$, with the susceptibilities obtained previously from the study of baryon magnetic moments. Our predictions on $D^{\ast}$ decays agree very well with the experimental data. There are differences among the various theoretical predictions on $B^{\ast}$ decays but the data are not yet available.Comment: 11 pages, Late

CP violation in the secluded U(1)'-extended MSSM

We study the Higgs sector of the secluded $U(1)'$-extended MSSM (sMSSM) focusing on CP violation. Using the one-loop effective potential that includes contributions from quarks and squarks in the third generation, we search for the allowed region under theoretical and experimental constraints. It is found that the possible region for the electroweak vacuum to exist is quite limited, depending on the parameters in the model. The masses and couplings of the Higgs bosons are calculated with/without CP violation. Even at the tree level, CP violation is possible by complex soft SUSY breaking masses. Similar to the CPX scenario in the MSSM, the scalar-pseudoscalar mixing enables the lightest Higgs boson mass to become smaller than the $Z$ boson mass while the coupling with the $Z$ boson is sufficiently suppressed to avoid the LEP experimental constraints. However, unlike the CPX scenario, large $\mu$ and $A$ are not required for the realization of large CP violation. The typical spectrum of the SUSY particles is thus different. We also investigate the possible upper bound of the lightest Higgs boson in the case of spontaneous CP violation. The maximal value of it can reach above 100 GeV with maximal CP-violating phases.Comment: 28 pages, 16 figures, JHEP styl

Higher Resonance Contributions to the Adler-Weisberger Sum Rule in the Large N_c Limit

We determine the $N_c$--dependence of the resonance contributions to the Adler--Weisberger sum rule for the inverse square $1/g_A^2$ of the axial charge coupling constant and show that in the large $N_c$ limit the contributions of the Roper-like excitations scale as $O(1/N_c)$. Consistency with the $1/N_c^2$ scaling of the $1/g_A^2$ term in the sum rule requires these contributions to cancel against each other.Comment: 10 pages, LaTeX, TH Darmstadt preprint IKDA 93/47, REVISE

Open Charm Enhancement in Pb+Pb Collisions at SPS

The statistical coalescence model for the production of open and hidden charm is considered within the canonical ensemble formulation. The data for the J/\psi multiplicity in Pb+Pb collisions at 158 A GeV are used for the model prediction of the open charm yield. We find a strong enhancement of the open charm production, by a factor of about 2--4, over the standard hard-collision model extrapolation from nucleon-nucleon to nucleus-nucleus collisions. A possible mechanism of the open charm enhancement in A+A collisions at the SPS energies is proposed.Comment: 4 pages, Late

Evaluating the spatial transferability and temporal repeatability of remote sensing-based lake water quality retrieval algorithms at the European scale:a meta-analysis approach

Many studies have shown the considerable potential for the application of remote-sensing-based methods for deriving estimates of lake water quality. However, the reliable application of these methods across time and space is complicated by the diversity of lake types, sensor configuration, and the multitude of different algorithms proposed. This study tested one operational and 46 empirical algorithms sourced from the peer-reviewed literature that have individually shown potential for estimating lake water quality properties in the form of chlorophyll-a (algal biomass) and Secchi disc depth (SDD) (water transparency) in independent studies. Nearly half (19) of the algorithms were unsuitable for use with the remote-sensing data available for this study. The remaining 28 were assessed using the Terra/Aqua satellite archive to identify the best performing algorithms in terms of accuracy and transferability within the period 2001–2004 in four test lakes, namely Vänern, Vättern, Geneva, and Balaton. These lakes represent the broad continuum of large European lake types, varying in terms of eco-region (latitude/longitude and altitude), morphology, mixing regime, and trophic status. All algorithms were tested for each lake separately and combined to assess the degree of their applicability in ecologically different sites. None of the algorithms assessed in this study exhibited promise when all four lakes were combined into a single data set and most algorithms performed poorly even for specific lake types. A chlorophyll-a retrieval algorithm originally developed for eutrophic lakes showed the most promising results (R2 = 0.59) in oligotrophic lakes. Two SDD retrieval algorithms, one originally developed for turbid lakes and the other for lakes with various characteristics, exhibited promising results in relatively less turbid lakes (R2 = 0.62 and 0.76, respectively). The results presented here highlight the complexity associated with remotely sensed lake water quality estimates and the high degree of uncertainty due to various limitations, including the lake water optical properties and the choice of methods

Neutrinos and Future Concordance Cosmologies

We review the free parameters in the concordance cosmology, and those which might be added to this set as the quality of astrophysical data improves. Most concordance parameters encode information about otherwise unexplored aspects of high energy physics, up to the GUT scale via the "inflationary sector," and possibly even the Planck scale in the case of dark energy. We explain how neutrino properties may be constrained by future astrophysical measurements. Conversely, future neutrino physics experiments which directly measure these parameters will remove uncertainty from fits to astrophysical data, and improve our ability to determine the global properties of our universe.Comment: Proceedings of paper given at Neutrino 2008 meeting (by RE

The High E_T Drop of J/psi to Drell-Yan Ratio from the Statistical c anti-c Coalescence Model

The dependence of the J/psi yield on the transverse energy E_T in heavy ion collisions is considered within the statistical c anti-c coalescence model. The model fits the NA50 data for Pb+Pb collisions at the CERN SPS even in the high-E_T region (E_T > 100 GeV). Here E_T-fluctuations and E_T-losses in the dimuon event sample naturally create the celebrated drop in the J/psi to Drell-Yan ratio.Comment: 14 pages, REVTeX, 1 PS-figure. v2: References are corrected and update

Higgs boson pair production process e+e−→ZHHe^+e^-\to ZHH in the littlest Higgs model at the ILC

The physics prospect at future linear $e^{+}e^{-}$ colliders for the study of the Higgs triple self-coupling via the process of $e^{+}e^{-}\to ZHH$ is investigated. In this paper, we calculate the contribution of the new particles predicted by the littlest Higgs model to the cross sections of this process in the future high energy $e^{+}e^{-}$ collider($ILC$). The results show that, in the favorable parameter spaces preferred by the electroweak precision, the deviation of the total cross sections from its $SM$ value varies from a few percent to tens percent, which may be detected at the future $ILC$ experiments with $\sqrt{s}$=500GeV.Comment: 13 pages,4 figure

Tevatron-for-LHC Report of the QCD Working Group

The experiments at Run 2 of the Tevatron have each accumulated over 1 inverse femtobarn of high-transverse momentum data. Such a dataset allows for the first precision (i.e. comparisons between theory and experiment at the few percent level) tests of QCD at a hadron collider. While the Large Hadron Collider has been designed as a discovery machine, basic QCD analyses will still need to be performed to understand the working environment. The Tevatron-for-LHC workshop was conceived as a communication link to pass on the expertise of the Tevatron and to test new analysis ideas coming from the LHC community. The TeV4LHC QCD Working Group focussed on important aspects of QCD at hadron colliders: jet definitions, extraction and use of Parton Distribution Functions, the underlying event, Monte Carlo tunes, and diffractive physics. This report summarizes some of the results achieved during this workshop.Comment: 156 pages, Tevatron-for-LHC Conference Report of the QCD Working Grou