13,378 research outputs found

    Reduced-Order Modelling of Parametric Systems via Interpolation of Heterogeneous Surrogates

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    PSR B1828-11: a precession pulsar torqued by a quark planet?

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    The pulsar PSR B1828-11 has long-term, highly periodic and correlated variations in both pulse shape and the rate of slow-down. This phenomenon may provide evidence for precession of the pulsar as suggested previously within the framework of free precession as well as forced one. On a presumption of forced precession, we propose a quark planet model to this precession henomenon instead, in which the pulsar is torqued by a quark planet. We construct this model by constraining mass of the pulsar (MpsrM_{\rm psr}), mass of the planet (MplM_{\rm pl}) and orbital radius of the planet (rplr_{\rm pl}). Five aspects are considered: derived relation between MpsrM_{\rm psr} and rplr_{\rm pl}, movement of the pulsar around the center of mass, ratio of MpsrM_{\rm psr} and MplM_{\rm pl}, gravitational wave radiation timescale of the planetary system, and death-line criterion. We also calculate the range of precession period derivative and gravitational wave strength (at earth) permitted by the model. Under reasonable parameters, the observed phenomenon can be understood by a pulsar (10−4∼10−1M⊙10^{-4}\sim10^{-1}M_{\odot}) with a quark planet (10−8∼10−3M⊙10^{-8}\sim10^{-3}M_{\odot}) orbiting it. According to the calculations presented, the pulsar would be a quark star because of its low mass, which might eject a lump of quark matter (to become a planet around) during its birth.Comment: 6 pages, 3 figures, accepted by MNRAS (Letters

    Symmetry-preserving Loop Regularization and Renormalization of QFTs

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    A new symmetry-preserving loop regularization method proposed in \cite{ylw} is further investigated. It is found that its prescription can be understood by introducing a regulating distribution function to the proper-time formalism of irreducible loop integrals. The method simulates in many interesting features to the momentum cutoff, Pauli-Villars and dimensional regularization. The loop regularization method is also simple and general for the practical calculations to higher loop graphs and can be applied to both underlying and effective quantum field theories including gauge, chiral, supersymmetric and gravitational ones as the new method does not modify either the lagrangian formalism or the space-time dimension of original theory. The appearance of characteristic energy scale McM_c and sliding energy scale μs\mu_s offers a systematic way for studying the renormalization-group evolution of gauge theories in the spirit of Wilson-Kadanoff and for exploring important effects of higher dimensional interaction terms in the infrared regime.Comment: 13 pages, Revtex, extended modified version, more references adde

    W±H∓W^{\pm}H^{\mp} associated production at LHC in the general 2HDM with Spontaneous CP Violation

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    Spontaneous CP violation motivates the introduction of two Higgs doublets in the electroweak theory. Such a simple extension of the standard model has three neutral Higgs bosons and a pair charged Higgs, especially it leads to rich CP-violating sources including the induced Kobayashi-Maskawa CP-violating phase, the mixing of the neutral Higgs bosons due to the CP-odd Higgs and the effective complex Yukawa couplings of the charged and neutral Higgs bosons. Within this model, we present the production of a charged Higgs boson in association with a W boson at the LHC, and calculate in detail the cross section and the transverse momentum distribution of the associated W boson.Comment: 16 pages, 6 figures, omitted 3 figures, motivations for Type III 2HDM with SCPV is emphasized, to be published in PR

    Implications of new data in charmless B decays

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    Based on the latest experimental data of B→ππB \to \pi\pi and πK\pi K modes, a model-independent analytical analysis is presented. The CP-averaged branching ratio difference ΔR=Rc−Rn\Delta R = R_c - R_n in B→πKB\to \pi K decays with Rc=2Br(π0K−)/Br(π−Kˉ0)R_c = 2Br(\pi^0K^-)/Br(\pi^-\bar{K}^0) and Rn=Br(π+K−)/2Br(π0Kˉ0)R_n =Br(\pi^+K^-)/2Br(\pi^0\bar{K}^0) is reduced though it remains larger than the prediction from the standard model(SM) as both measured RnR_n and RcR_c are enhanced, which indicates that a room for new physics becomes smaller. The present data of ππ\pi\pi decay reduce the ratio ∣C/T∣|C/T| from the previous value of ∣C/T∣≃0.8|C/T|\simeq 0.8 to ∣C/T∣≃0.65|C/T| \simeq 0.65, which is still larger than the theoretical estimations based on QCD factorization and pQCD. Within SM and flavor SU(3) symmetry, the current πK\pi K data also diminish the ratio ∣C′/T′∣|C'/T'| from the previous value ∣C′/T′∣≃2|C'/T'| \simeq 2 to ∣C′/T′∣≃1.16|C'/T'| \simeq 1.16 with a large strong phase δC′≃−2.65\delta_{C'} \simeq -2.65, while its value remains much larger than the one extracted from the ππ\pi \pi modes. The direct CP violation ACP(π0Kˉ0)A_{CP}(\pi^0\bar{K}^0) is predicted to be ACP(π0Kˉ0)=−0.15±0.03A_{CP}(\pi^0\bar{K}^0) = -0.15\pm0.03, which is consistent with the present data. Two kinds of new effects in both strong and weak phases of the electroweak penguin diagram are considered. It is found that both cases can reduce the ratio to ∣C′/T′∣=0.40∼0.80|C'/T'| = 0.40\sim 0.80 and lead to roughly the same predictions for CP violation in π0K0\pi^0 K^0.Comment: 13 pages, 4 figure

    Charmless decays B->pipi, piK and KK in broken SU(3)symmetry

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    Charmless B decay modes B→ππ,πKB \to \pi \pi, \pi K and KKKK aresystematically investigated with and without flavor SU(3) symmetry. Independent analyses on ππ\pi \pi and πK\pi K modes both favor a large ratio between color-suppressed tree (CC) and tree (T)T) diagram, which suggests that they are more likely to originate from long distance effects. The sizes of QCD penguin diagrams extracted individually from ππ\pi\pi, πK\pi K and KKKK modes are found to follow a pattern of SU(3) breaking in agreement with the naive factorization estimates. Global fits to these modes are done under various scenarios of SU(3)relations. The results show good determinations of weak phase γ\gamma in consistency with the Standard Model (SM), but a large electro-weak penguin (P_{\tmop{EW}}) relative to T+CT + C with a large relative strong phase are favored, which requires an big enhancement of color suppressed electro-weak penguin (P_{\tmop{EW}}^C) compatible in size but destructively interfering with P_{\tmop{EW}} within the SM, or implies new physics. Possibility of sizable contributions from nonfactorizable diagrams such as WW-exchange (EE), annihilation(AA) and penguin-annihilation diagrams(PAP_A) are investigated. The implications to the branching ratios and CP violations in KKK Kmodes are discussed.Comment: 27 pages, 9 figures, reference added, to appear in Phy.Rev.

    Exclusive B→PVB \to PV Decays and CP Violation in the General two-Higgs-doublet Model

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    We calculate all the branching ratios and direct CP violations of B→PVB \to PV decays in a most general two-Higgs-doublet model with spontaneous CP violation. As the model has rich CP-violating sources, it is shown that the new physics effects to direct CP violations and branching ratios in some channels can be significant when adopting the generalized factorization approach to evaluate the hadronic matrix elements, which provides good signals for probing new physics beyond the SM in the future B experiments.Comment: 21 page

    Calculation of composition distribution of ultrafine ion-H2O-H2SO4 clusters using a modified binary ion nucleation theory

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    Thomson's ion nucleation theory was modified to include the effects of curvature dependence of the microscopic surface tension of field dependent, nonlinear, dielectric properties of the liquid; and of sulfuric acid hydrate formation in binary mixtures of water and sulfuric acid vapors. The modified theory leads to a broadening of the ion cluster spectrum, and shifts it towards larger numbers of H2O and H2SO4 molecules. Whether there is more shifting towards larger numbers of H2O or H2SO4 molecules depends on the relative humidity and relative acidity of the mixture. Usually, a broadening of the spectrum is accompanied by a lowering of the mean cluster intensity. For fixed values of relative humidity and relative acidity, a similar broadening pattern is observed when the temperature is lowered. These features of the modified theory illustrate that a trace of sulfuric acid can facilitate the formation of ultrafine, stable, prenucleation ion clusters as well as the growth of the prenucleation ion clusters towards the critical saddle point conditions, even with low values of relative humidity and relative acidity
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