86,966 research outputs found

    Inclusive Decays of Bottom Hadrons in New Formulation of Heavy Quark Effective Field Theory

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    We apply the new formulation of heavy quark effective field theory (HQEFT) to the inclusive decays of bottom hadrons. The long-term ambiguity of using heavy quark mass or heavy hadron mass for inclusive decays is clarified within the framework of the new formulation of HQEFT. The 1/mb1/m_b order corrections are absent and contributions from 1/mb21/m_b^2 terms are calculated in detail. This enables us to reliably extract the important CKM matrix element ∣Vcb∣|V_{cb}| from the inclusive semileptonic decay rates. The resulting lifetime ratios τ(Bs0)/τ(B0)\tau(B^0_s)/\tau(B^0) and τ(Λb)/τ(B0)\tau(\Lambda_b)/\tau(B^0) are found to well agree with the experimental data. We also calculate in detail the inclusive semileptonic branching ratios and the ratios of the τ\tau and β\beta decay rates as well as the charm countings in the B0B^0, Bs0B^0_s and Λb\Lambda_b systems. For B0B^0 decays, all the observables are found to be consistent with the experimental data. More precise data for the B0B^0 decays and further experimental measurements for the Bs0B^0_s and Λb\Lambda_b systems will be very useful for testing the framework of new formulation of HQEFT at the level of higher order corrections.Comment: 20 pages, RevTex, 8 figures, 3 tables, revised version with `dressed heavy quark' being addressed, to be published in Int. J. Mod. Phys.

    Implications of Recent Bˉ0→D(∗)0X0\bar{B}^0\to D^{(*)0}X^0 Measurements

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    The recent measurements of the color-suppressed modes Bˉ0→D(∗)0π0\bar B^0\to D^{(*)0}\pi^0 imply non-vanishing relative final-state interaction (FSI) phases among various Bˉ→Dπ\bar B\to D\pi decay amplitudes. Depending on whether or not FSIs are implemented in the topological quark-diagram amplitudes, two solutions for the parameters a1a_1 and a2a_2 are extracted from data using various form-factor models. It is found that a2a_2 is not universal: ∣a2(Dπ)∣=0.40−0.55|a_2(D\pi)|= 0.40-0.55 and ∣a2(D∗π)∣=0.25−0.35|a_2(D^*\pi)|= 0.25-0.35 with a relative phase of order (50−55)∘(50-55)^\circ between a1a_1 and a2a_2. If FSIs are not included in quark-diagram amplitudes from the outset, a2eff/a1effa_2^{eff}/a_1^{eff} and a2effa_2^{eff} will become smaller. The large value of ∣a2(Dπ)∣|a_2(D\pi)| compared to ∣a2eff(Dπ)∣|a_2^{eff}(D\pi)| or naive expectation implies the importance of long-distance FSI contributions to color-suppressed internal WW-emission via final-state rescatterings of the color-allowed tree amplitude.Comment: 17 pages. The Introduction is substantially revised and the order of the presentation in Sec. 2 is rearranged. To appear in Phys. Re

    Final stare interaction enhancement effect on the near threshold p\bar p system in B^\pm\to p\bar p \p^\pm decay

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    We discuss the low-mass enhancement effect in the baryon-antibaryon invariant mass in three-body baryonic B decays using final state interactions in the framework of Regge theory. We show that the rescattering between baryonic pair can reproduce the observed mass spectrum.Comment: 7 pages, 11 figure

    Three-dimensional physics and the pressure of hot QCD

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    We update Monte Carlo simulations of the three-dimensional SU(3) + adjoint Higgs theory, by extrapolating carefully to the infinite volume and continuum limits, in order to estimate the contribution of the infrared modes to the pressure of hot QCD. The sum of infrared contributions beyond the known 4-loop order turns out to be a smooth function, of a reasonable magnitude and specific sign. Unfortunately, adding this function to the known 4-loop terms does not improve the match to four-dimensional lattice data, in spite of the fact that other quantities, such as correlation lengths, spatial string tension, or quark number susceptibilities, work well within the same setup. We outline possible ways to reduce the mismatch.Comment: 14 page

    Dominant moving species in the formation of amorphous NiZr by solid-state reaction

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    The displacements of W and Hf markers have been monitored by backscattering of MeV He to study the growth of the amorphous NiZr phase by solid-state reaction. We find that the Ni is the dominant moving species in this reaction
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