250 research outputs found

    Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex

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    6,6â€Čâ€Č‐Bis(2,4,6‐trimethylanilido)terpyridine (H2TpyNMes) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H2TpyNMes)copper(I)‐halide (Cl, Br and I) complexes is dictated by the strength of the NH–halide hydrogen bond. The CuICl and CuIICl complexes are nearly isostructural, the former presenting a highly unusual square‐planar geometry about CuI. The geometric constraints provided by secondary interactions are reminiscent of blue copper proteins where a constrained geometry, or entatic state, allows for extremely rapid CuI/CuII electron‐transfer self‐exchange rates. Cu(H2TpyNMes)Cl shows similar fast electron transfer (≈105 m−1 s−1) which is the same order of magnitude as biological systems.Entatic state: Hydrogen bonds constrain the geometry of CuI and CuII complexes. A highly unusual square‐planar geometry about CuI (see structure) is shown to be nearly isostructural to the CuII core. The minimal reorganization energy between redox states allows for extremely rapid CuI/CuII electron‐transfer self‐exchange rates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/1/anie201511527_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/2/anie201511527-sup-0001-misc_information.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134494/3/anie201511527.pd

    Testing Higgs models via the H±W∓ZH^\pm W^\mp Z vertex by a recoil method at the International Linear Collider

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    In general, charged Higgs bosons H±H^\pm appear in non-minimal Higgs models. The H±W∓ZH^\pm W^\mp Z vertex is known to be related to the violation of the global symmetry (custodial symmetry) in the Higgs sector. Its magnitude strongly depends on the structure of the exotic Higgs models which contain higher isospin SU(2)LSU(2)_L representations such as triplet Higgs bosons. We study the possibility of measuring the H±W∓ZH^\pm W^\mp Z vertex via single charged Higgs boson production associated with the W±W^\pm boson at the International Linear Collider (ILC) by using the recoil method. The feasibility of the signal e+e−→H±W∓→ℓΜjje^+e^-\to H^\pm W^\mp \to \ell \nu jj is analyzed assuming the polarized electron and positron beams and the expected detector performance for the resolution of the two-jet system at the ILC. The background events can be reduced to a considerable extent by imposing the kinematic cuts even if we take into account the initial state radiation. For a relatively light charged Higgs boson whose mass mH±m_{H^\pm} is in the region of 120-130 GeV <mH±<mW+mZ< m_{H^\pm} < m_W+m_Z, the H±W∓ZH^\pm W^\mp Z vertex would be precisely testable especially when the decay of H±H^\pm is lepton specific. The exoticness of the extended Higgs sector can be explored by using combined information for this vertex and the rho parameter.Comment: 22 pages, 23 figure

    Higgs-gauge boson interactions in the economical 3-3-1 model

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    Interactions among the standard model gauge bosons and scalar fields in the framework of SU(3)_C X SU(3)_L X U(1)_X gauge model with minimal (economical) Higgs content are presented. From these couplings, all scalar fields including the neutral scalar hh and the Goldstone bosons can be identified and their couplings with the usual gauge bosons such as the photon, the charged W±W^\pm and the neutral ZZ, without any additional condition, are recovered. In the effective approximation, full content of scalar sector can be recognized. The CP-odd part of Goldstone associated with the neutral non-Hermitian bilepton gauge boson GX0G_{X^0} is decouple, while its CP-even counterpart has the mixing by the same way in the gauge boson sector. Masses of the new neutral Higgs boson H10H^0_1 and the neutral non-Hermitian bilepton X0X^0 are dependent on a coefficient of Higgs self-coupling (λ1\lambda_1). Similarly, masses of the singly-charged Higgs boson H2±H_2^\pm and of the charged bilepton Y±Y^\pm are proportional through a coefficient of Higgs self-interaction (λ4\lambda_4). The hadronic cross section for production of this Higgs boson at the LHC in the effective vector boson approximation is calculated. Numerical evaluation shows that the cross section can exceed 260 fbfb.Comment: 22 pages, 1 figure, submitted to Phys. Rev.

    Experiments on the generation of long wavelength edge radiation along directions nearly coincident with the axis of a straight section of the "Pakhra" synchrotron

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    Generation of long wavelength edge radiation along directions nearly coincident with the axes of straight sections of storage rings and synchrotrons is discussed. The removal of destructive interference from the superimposed edge radiation patterns of a straight section on the synchrotron "Pakhra" has been observed experimentally.Comment: 8 pages, LaTeX, Presented to Proc. IV Int. Symp. Radiation from Relativistic Electrons in periodic Structures, (RREPS'99) September 13-16, 1999, Lake Baikal, Russia (Proc. will be published in Nucl. Instr. Meth.). Figures were replace

    CP-odd Higgs boson production in association with Neutral gauge boson in High-Energy e+e−e^+e^- Collisions

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    We study the associated production of a CP-odd Higgs boson A0A^0 with a neutral gauge boson (ZZ or photon) in high-energy e+e−e^+ e^- collisions at the one-loop level in the framework of Two Higgs Doublet Models (THDM). We find that in the small tan⁥ÎČ\tan\beta regime the top quark loop contribution is enhanced leading to significant cross-sections (about a few fb), while in the large tan⁥ÎČ\tan\beta regime the cross-section does not attain observable rates.Comment: 16 pages Latex, 4 figures, figures in agreement with erratu

    Associated H−^{-} W+^{+} Production in High Energy e+e−e^+e^- Collisions

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    We study the associated production of charged Higgs bosons with WW gauge bosons in high energy e+e−e^+ e^- collisions at the one loop level. We present the analytical results and give a detailed discussion for the total cross section predicted in the context of a general Two Higgs Doublet Model (THDM).Comment: Latex, 31 pages, 6 figures, cosmetically improved and one reference adde

    Vector Boson Pair Production in Hadronic Collisions at Order αs\alpha_s: Lepton Correlations and Anomalous Couplings

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    We present cross sections for production of electroweak vector boson pairs, WWWW, WZWZ and ZZZZ, in ppˉp\bar{p} and pppp collisions, at next-to-leading order in αs\alpha_s. We treat the leptonic decays of the bosons in the narrow-width approximation, but retain all spin information via decay angle correlations. We also include the effects of WWZWWZ and WWÎłWW\gamma anomalous couplings.Comment: 23 pages, 8 figures, 3 table

    Investigating the Temporary and Longer-Term Impacts of the COVID-19 Pandemic on Mobility in California

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    Caltrans 65A0686 Task Order 059 USDOT Grant 69A3551747114This study investigates how the COVID-19 pandemic has transformed people\u2019s activity-travel patterns, using datasets collected through three waves of surveys in spring 2020, fall 2020, and summer 2021. With this dataset, it was possible to investigate evolving behavioral choices and preferences among respondents at different timepoints: fall 2019 (recollection of the past), spring 2020, fall 2020, summer 2021, and summer 2022 (future expectations). The study highlighted a large shift among California workers from physical commuting to working remotely in 2020, which was followed by a transition towards hybrid work by summer 2021. The shift to remote work and hybrid work varied considerably across population subgroups, and was most popular among higher-income, better-educated individuals, and urban residents. In terms of household vehicle ownership change, those tech-savvy and variety-seeking individuals were more likely to increase or replace household vehicles, while those who are pro-environment and pro-active are less likely to do so. COVID health concerns show concurrent effects of encouraging the adoption of a more pro-active lifestyle during the pandemic, but also leading to an increased desire to own vehicles in the future. Regarding shopping patterns, the number of respondents who shop online at least once per week increased nearly five-fold between fall 2019 and spring 2020, but such magnitude somewhat diminished by fall 2020. In general, the pandemic has generated a mix of short-lived temporary changes and potential longer-term impacts. The study provides various strategies to help increase transportation and social equity among various population groups as the communities recover from the pandemic

    Deciphering the Factors Associated With Adoption of Alternative Fuel Vehicles in California: An Investigation of Latent Attitudes, Socio-Demographics, and Neighborhood Effects

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    This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) license https://creativecommons.org/licenses/by/4.0/. Please cite this article as:Xiatian Iogansen, Kailai Wang, David Bunch, Grant Matson, Giovanni Circella, Deciphering the factors associated with adoption of alternative fuel vehicles in California: An investigation of latent attitudes, socio-demographics, and neighborhood effects, Transportation Research Part A: Policy and Practice, Volume 168, 2023, 103535, ISSN 0965-8564, https://doi.org/10.1016/j.tra.2022.10.012.Promoting the use of alternative fuel vehicles (AFVs) has become a long-term transportation strategy in California, which can bring a broad range of social, economic, and environmental benefits. Based on a sample of 3260 California residents from the 2018 California Panel Survey, this study explores the impacts of latent attitudes, socio-demographic characteristics, and neighborhood effects on consumers\u2019 current vehicle fuel type choice and their interest in purchasing or leasing an AFV in the future
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