Disentangling Neutrino Oscillations

The theory underlying neutrino oscillations has been described at length in the literature. The neutrino state produced by a weak decay is usually portrayed as a linear superposition of mass eigenstates with, variously, equal energies or equal momenta. We point out that such a description is incomplete, that in fact, the neutrino is entangled with the other particle or particles emerging from the decay. We offer an analysis of oscillation phenomena involving neutrinos (applying equally well to neutral mesons) that takes entanglement into account. Thereby we present a theoretically sound proof of the universal validity of the oscillation formulae ordinarily used. In so doing, we show that the departures from exponential decay reported by the GSI experiment cannot be attributed to neutrino mixing. Furthermore, we demonstrate that the `Mossbauer' neutrino oscillation experiment proposed by Raghavan, while technically challenging, is correctly and unambiguously describable by means of the usual oscillation formalae.Comment: 16 page

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

Charmless B decay modes $B \to \pi \pi, \pi K$ and $KK$ aresystematically investigated with and without flavor SU(3) symmetry. Independent analyses on $\pi \pi$ and $\pi K$ modes both favor a large ratio between color-suppressed tree ($C$) and tree ($T)$ diagram, which suggests that they are more likely to originate from long distance effects. The sizes of QCD penguin diagrams extracted individually from $\pi\pi$, $\pi K$ and $KK$ 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 $\gamma$ in consistency with the Standard Model (SM), but a large electro-weak penguin (P_{\tmop{EW}}) relative to $T + C$ 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 $W$-exchange ($E$), annihilation($A$) and penguin-annihilation diagrams($P_A$) are investigated. The implications to the branching ratios and CP violations in $K K$modes are discussed.Comment: 27 pages, 9 figures, reference added, to appear in Phy.Rev.

The quest for the Cabibbo Kobayashi Maskawa Matrix

A piece of the Standard Model presently undergoing intense experimental scrutiny is the Cabibbo Kobayashi Maskawa matrix. Several different measurements are planned to enrich the spectrum of experimental constraints and thus provide one of the most stringent tests of Standard Model validity. The success of this program is closely related to theoretical progress in evaluating QCD matrix elements in a non-perturbative regime, as we need to extract fundamental quark properties from observations on decays involving hadrons. This interplay between experimental and theoretical progress will be illustrated in the context of the present knowledge of the magnitudes of the quark mixing parameters $| V_{cb}|$ and $| V_{ub}|$.Comment: 10 pages, 1 figure, contributed paper to BEAUTY 200

New Predictions for Λb→Λc{\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c} Semileptonic Decays and Tests of Heavy Quark Symmetry

The heavy quark effective theory makes model independent predictions for semileptonic ${\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}$ decays in terms of a small set of parameters. No subleading Isgur-Wise function occurs at order ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}/{m}_{c,b}$, and only two subsubleading functions enter at order ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}^{2}/{m}_{c}^{2}$. These features allow us to fit the form factors and decay rates calculated up to order ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}^{2}/{m}_{c}^{2}$ to LHCb data and lattice QCD calculations. We derive a significantly more precise standard model prediction for the ratio $\mathcal{B}({\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}{\tau}\overline{{\nu}})/\mathcal{B}({\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}{\mu}\overline{{\nu}})$ than prior results, and find the expansion in ${\mathrm{{\Lambda}}}_{\mathrm{QCD}}/{m}_{c}$ well behaved, addressing a long-standing question. Our results allow more precise and reliable calculations of ${\mathrm{{\Lambda}}}_{b}{\rightarrow}{\mathrm{{\Lambda}}}_{c}{\ell}\overline{{\nu}}$ rates, and are systematically improvable with better data on the ${\mu}$ (or $e$) modes

New Predictions for Λ_{b}→Λ_{c} Semileptonic Decays and Tests of Heavy Quark Symmetry.

The heavy quark effective theory makes model independent predictions for semileptonic Λ_{b}→Λ_{c} decays in terms of a small set of parameters. No subleading Isgur-Wise function occurs at order Λ_{QCD}/m_{c,b}, and only two subsubleading functions enter at order Λ_{QCD}^{2}/m_{c}^{2}. These features allow us to fit the form factors and decay rates calculated up to order Λ_{QCD}^{2}/m_{c}^{2} to LHCb data and lattice QCD calculations. We derive a significantly more precise standard model prediction for the ratio B(Λ_{b}→Λ_{c}τν[over ¯])/B(Λ_{b}→Λ_{c}μν[over ¯]) than prior results, and find the expansion in Λ_{QCD}/m_{c} well behaved, addressing a long-standing question. Our results allow more precise and reliable calculations of Λ_{b}→Λ_{c}ℓν[over ¯] rates, and are systematically improvable with better data on the μ (or e) modes