541 research outputs found

    Muon anomalous magnetic moment in the standard model with two Higgs doublets

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    The muon anomalous magnetic moment is investigated in the standard model with two Higgs doublets (S2HDM) motivated from spontaneous CP violation. Thus all the effective Yukawa couplings become complex. As a consequence of the non-zero phase in the couplings, the one loop contribution from the neutral scalar bosons could be positive and negative relying on the CP phases. The interference between one and two loop diagrams can be constructive in a large parameter space of CP-phases. This will result in a significant contribution to muon anomalous magnetic moment even in the flavor conserving process with a heavy neutral scalar boson (mh∌m_h \sim 200 GeV) once the effective muon Yukawa coupling is large (âˆŁÎŸÎŒâˆŁâˆŒ50|\xi_\mu|\sim 50). In general, the one loop contributions from lepton flavor changing scalar interactions become more important. In particular, when all contributions are positive in a reasonable parameter space of CP phases, the recently reported 2.6 sigma experiment vs. theory deviation can be easily explained even for a heavy scalar boson with a relative small Yukawa coupling in the S2HDM.Comment: 8 pages, RevTex file, 5 figures, published version Phys. Rev. D 54 (2001) 11501

    Elemental and Sr–Nd–Pb isotope geochemistry of the Cenozoic basalts in Southeast China : insights into their mantle sources and melting processes.

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    We analyzed whole-rock major and trace elements and Sr–Nd–Pb isotopes of the Cenozoic basalts in Southeast China to investigate their mantle source characteristics and melting process. These basalts are spatially associated with three extensional fault systems parallel to the coast line. After correction for the effect of olivine microlites on bulk-rock compositions and the effect of crystal fractionation, we obtained primitive melt compositions for these samples. These primitive melts show increasing SiO2, Al2O3 but decreasing FeO, MgO, TiO2, P2O5, CaO and CaO/Al2O3 from the interior to the coast. Such spatial variations of major element abundances and ratios are consistent with a combined effect of fertile source compositional variation and increasing extent and decreasing pressure of decompression melting from beneath the thick lithosphere in the interior to beneath the thin lithosphere in the coast. These basalts are characterized by incompatible element enrichment but varying extent of isotopic depletion. This element-isotope decoupling is most consistent with recent mantle source enrichment by means of low-degree melt metasomatism that elevated incompatible element abundances without yet having adequate time for isotopic ingrowth in the mantle source regions. Furthermore, Sr and Nd isotope ratios show significant correlations with Nb/Th, Nb/La, Sr/Sr⁎ and Eu/Eu⁎, which substantiates the presence of recycled upper continental crustal material in the mantle sources of these basalts. Pb isotope ratios also exhibit spatial variation, increasing from the interior to the coastal area. The significant correlations of major element abundances with Pb isotope ratios indicate that the Pb isotope variations also result from varied extent and pressure of decompression melting. We conclude that the elevated Pb isotope ratios from the interior to coast are consistent with increasing extent of decompression melting of the incompatible element depleted mantle matrix, which hosts enriched Pb isotope compositions

    The Pinch Technique to All Orders

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    The generalization of the pinch technique to all orders in perturbation theory is presented. The effective Green's functions constructed with this procedure are singled out in a unique way through the full exploitation of the underlying Becchi-Rouet-Stora-Tyutin symmetry. A simple all-order correspondence between the pinch technique and the background field method in the Feynman gauge is established.Comment: 10 pages, 4 figures; one reference added, typos corrected; final version to match the pubblished on

    Weak Phase Îł\gamma and Strong Phase ÎŽ\delta from CP Averaged B→ππB\to \pi\pi and πK\pi K Decays

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    Assuming SU(3) symmetry for the strong phases in the four decay modes B\rarrow \pi^-\pi^+, \pi^0 \pi^+, \pi^- K^+, \pi^- \bar{K}^0 and ignoring the relative small electroweak penguin effects in those decays, the weak phase Îł\gamma and the strong phase ÎŽ\delta can be determined in a model independent way by the CP-averaged branching ratios of the four decay modes. It appears that the current experimental data for B→ππB\to \pi\pi and πK\pi K decays prefer a negative value of cos⁥γcos⁥Ύ\cos\gamma\cos\delta. By combining with the other constraints from VubV_{ub}, Bd,s0−Bˉd,s0B^{0}_{d,s}-\bar{B}^{0}_{d,s} mixings and indirect CP-violating parameter Ï”K\epsilon_K within the standard model, two favorable solutions for the phases Îł\gamma and ÎŽ\delta are found to lie in the region: 35^{\circ}\alt\gamma\alt 62^{\circ} and 106^{\circ}\alt \delta \alt 180^{\circ} or 86^{\circ}\alt\gamma\alt 151^{\circ} and 0^{\circ}\alt\delta\alt 75^{\circ} within 1σ\sigma standard deviation. It is noted that if allowing the standard deviation of the data to be more than 1σ\sigma, the two solutions could approach to one solution with a much larger region for the phases Îł\gamma and ÎŽ\delta. Direct CP asymme try aÏ”â€Čâ€Č(π−K+)a_{\epsilon''}^{(\pi^- K^+)} in B\rarrow \pi^-K^+ decay can be as large as the present experimental upper bound. Direct CP asymmetry aÏ”â€Čâ€Č(π+π−)a_{\epsilon''}^{(\pi^+\pi^-)} in B\rarrow \pi^-\pi^+ decay can reach up to about 40% at 1σ\sigma level.Comment: 14 Pages, ReVTeX, 5 figures, one figure (Fig.3) is correcte

    Multifractal Analysis of inhomogeneous Bernoulli products

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    We are interested to the multifractal analysis of inhomogeneous Bernoulli products which are also known as coin tossing measures. We give conditions ensuring the validity of the multifractal formalism for such measures. On another hand, we show that these measures can have a dense set of phase transitions

    Lyapunov spectrum of asymptotically sub-additive potentials

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    For general asymptotically sub-additive potentials (resp. asymptotically additive potentials) on general topological dynamical systems, we establish some variational relations between the topological entropy of the level sets of Lyapunov exponents, measure-theoretic entropies and topological pressures in this general situation. Most of our results are obtained without the assumption of the existence of unique equilibrium measures or the differentiability of pressure functions. Some examples are constructed to illustrate the irregularity and the complexity of multifractal behaviors in the sub-additive case and in the case that the entropy map that is not upper-semi continuous.Comment: 44 page

    Science Development

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68479/2/10.1177_107554708500600404.pd

    Pathways to Next-Generation Fire-Safe Alkali-Ion Batteries

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    Published online: OnlinePublHigh energy and power density alkali-ion (i.e., Li+ , Na+ , and K+ ) batteries (AIBs), especially lithium-ion batteries (LIBs), are being ubiquitously used for both large- and small-scale energy storage, and powering electric vehicles and electronics. However, the increasing LIB-triggered fires due to thermal runaways have continued to cause significant injuries and casualties as well as enormous economic losses. For this reason, to date, great efforts have been made to create reliable fire-safe AIBs through advanced materials design, thermal management, and fire safety characterization. In this review, the recent progress is highlighted in the battery design for better thermal stability and electrochemical performance, and state-of-the-art fire safety evaluation methods. The key challenges are also presented associated with the existing materials design, thermal management, and fire safety evaluation of AIBs. Future research opportunities are also proposed for the creation of next-generation fire-safe batteries to ensure their reliability in practical applications.Yubai Zhang, Jiabing Feng, Jiadong Qin, Yu Lin Zhong, Shanqing Zhang, Hao Wang, John Bell, Zaiping Guo, and Pingan Son

    The lifetime of B_c-meson and some relevant problems

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    The lifetime of the B_c-meson is estimated with consistent considerations on all of the heavy mesons (B0,B±,Bs,D0,D±DsB^0, B^\pm, B_s, D^0, D^\pm D_s) and the double heavy meson B_c. In the estimate, the framework, where the non-spectator effects for nonleptonic decays are taken into account properly, is adopted, and the parameters needed to be fixed are treated carefully and determined by fitting the available data. The bound-state effects in it are also considered. We find that in decays of the meson B_c, the QCD correction terms of the penguin diagrams and the main component terms c_1O_1, c_2O_2 of the effective interaction Lagrangian have direct interference that causes an enhancement about 3 ~ 4% in the total width of the B_c meson.Comment: 27 pages, 0 figur

    Structure of Schlafen13 reveals a new class of tRNA/rRNA- targeting RNase engaged in translational control

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    Cleavage of transfer (t)RNA and ribosomal (r)RNA are critical and conserved steps of translational control for cells to overcome varied environmental stresses. However, enzymes that are responsible for this event have not been fully identified in high eukaryotes. Here, we report a mammalian tRNA/rRNA-targeting endoribonuclease: SLFN13, a member of the Schlafen family. Structural study reveals a unique pseudo-dimeric U-pillow-shaped architecture of the SLFN13 N'-domain that may clamp base-paired RNAs. SLFN13 is able to digest tRNAs and rRNAs in vitro, and the endonucleolytic cleavage dissevers 11 nucleotides from the 3'-terminus of tRNA at the acceptor stem. The cytoplasmically localised SLFN13 inhibits protein synthesis in 293T cells. Moreover, SLFN13 restricts HIV replication in a nucleolytic activity-dependent manner. According to these observations, we term SLFN13 RNase S13. Our study provides insights into the modulation of translational machinery in high eukaryotes, and sheds light on the functional mechanisms of the Schlafen family
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