63,877 research outputs found

    CP violation at one loop in the polarization-independent chargino production in e+e- collisions

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    Recently Osland and Vereshagin noticed, based on sample calculations of some box diagrams, that in unpolarised e+e- collisions CP-odd effects in the non-diagonal chargino-pair production process are generated at one-loop. Here we perform a full one-loop analysis of these effects and point out that in some cases the neglected vertex and self-energy contributions may play a dominant role. We also show that CP asymmetries in chargino production are sensitive not only to the phase of mu parameter in the chargino sector but also to the phase of stop trilinear coupling A_t.Comment: 14 pages, 5 figure

    Local well-posedness of the generalized Cucker-Smale model

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    In this paper, we study the local well-posedness of two types of generalized Cucker-Smale (in short C-S) flocking models. We consider two different communication weights, singular and regular ones, with nonlinear coupling velocities vvβ2v|v|^{\beta-2} for β>3d2\beta > \frac{3-d}{2}. For the singular communication weight, we choose ψ1(x)=1/xα\psi^1(x) = 1/|x|^{\alpha} with α(0,d1)\alpha \in (0,d-1) and β2\beta \geq 2 in dimension d>1d > 1. For the regular case, we select ψ2(x)0\psi^2(x) \geq 0 belonging to (L_{loc}^\infty \cap \mbox{Lip}_{loc})(\mathbb{R}^d) and β(3d2,2)\beta \in (\frac{3-d}{2},2). We also remark the various dynamics of C-S particle system for these communication weights when β(0,3)\beta \in (0,3)

    A molecular dynamics computer simulation study of room-temperature ionic liquids. I. Equilibrium solvation structure and free energetics

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    Solvation in 1-ethyl-3-methylmidazolium chloride and in 1-ethyl-3-methylimidazolium hexafluorophosphate near equilibrium is investigated via molecular dynamics computer simulations with diatomic and benzenelike molecules employed as probe solutes. It is found that electrostriction plays an important role in both solvation structure and free energetics. The angular and radial distributions of cations and anions become more structured and their densities near the solute become enhanced as the solute charge separation grows. Due to the enhancement in structural rigidity induced by electrostriction, the force constant associated with solvent configuration fluctuations relevant to charge shift and transfer processes is also found to increase. The effective polarity and reorganization free energies of these ionic liquids are analyzed and compared with those of highly polar acetonitrile. Their screening behavior of electric charges is also investigated.Comment: 12 page

    The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC

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    We compute the rates for pp annihilation into chargino-pairs via Drell-Yan process taking into account the effects of supersymmetric soft phases, at proton-proton collider. In particular, the phase of the mu parameter gains direct accessibility via the production of dissimilar charginos. The phases of the trilinear soft masses do not have a significant effect on the cross sections.Comment: 24 pages, 7 figure

    Relation between Kitaev magnetism and structure in α\alpha-RuCl3_3

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    Raman scattering has been employed to investigate lattice and magnetic excitations of the honeycomb Kitaev material α\alpha-RuCl3_3 and its Heisenberg counterpart CrCl3_3. Our phonon Raman spectra give evidence for a first-order structural transition from a monoclinic to a rhombohedral structure for both compounds. Significantly, only α\alpha-RuCl3_3 features a large thermal hysteresis, consistent with the formation of a wide phase of coexistence. In the related temperature interval of 7017070-170 K, we observe a hysteretic behavior of magnetic excitations as well. The stronger magnetic response in the rhombohedral compared to the monoclinic phase evidences a coupling between the crystallographic structure and low-energy magnetic response. Our results demonstrate that the Kitaev magnetism concomitant with fractionalized excitations is susceptible to small variations of bonding geometry.Comment: 9 pages, 8 figures, To appear in PR

    Collective phase synchronization in locally-coupled limit-cycle oscillators

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    We study collective behavior of locally-coupled limit-cycle oscillators with scattered intrinsic frequencies on dd-dimensional lattices. A linear analysis shows that the system should be always desynchronized up to d=4d=4. On the other hand, numerical investigation for d=5d= 5 and 6 reveals the emergence of the synchronized (ordered) phase via a continuous transition from the fully random desynchronized phase. This demonstrates that the lower critical dimension for the phase synchronization in this system is $d_{l}=4
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