6,270 research outputs found

    Nonfactorization in Hadronic Two-body Cabibbo-favored decays of D^0 and D^+

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    With the inclusion of nonfactorized amplitudes in a scheme with Nc=3N_c=3, we have studied Cabibbo-favored decays of D0D^0 and D+D^+ into two-body hadronic states involving two isospins in the final state. We have shown that it is possible to understand the measured branching ratios and determined the sizes and signs of nonfactorized amplitudes required.Comment: 15 pages, Late

    Inelastic Final-State Interactions and Two-body Hadronic B decays into Single-Isospin channels

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    The role of inelastic final-state interactions in CP asymmetries and branching ratios is investigated in certain chosen single isospin two-body hadronic B decays. Treating final-state interactions through Pomeron and Regge exchanges, we demonstrate that inelastic final state interactions could lead to sizeable effects on the CP asymmetry.Comment: 23 pages, Latex, 1 eps-figur

    Baryons and baryonic matter in the large Nc and heavy quark limits

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    This paper explores properties of baryons and finite density baryonic matter in an artificial world in which Nc, the number of colors, is large and the quarks of all species are degenerate and much larger than {\Lambda}_QCD. It has long been known that in large Nc QCD, baryons composed entirely of heavy quarks are accurately described in the mean-field approximation. However, the detailed properties of baryons in the combined large Nc and heavy quark limits have not been fully explored. Here some basic properties of baryons are computed using a variational approach. At leading order in both the large Nc and heavy quark expansions the baryon mass is computed explicitly as is the baryon form factor. Baryonic matter, the analog of nuclear matter in this artificial world, should also be well described in the mean-field approximation. In the special case where all baryons have an identical spin flavor structure, it is shown that in the formal heavy quark and large Nc limit interactions between baryons are strictly repulsive at low densities. The energy per baryon is computed in this limit and found to be exponentially small. It is shown that when the restriction to baryons with an identical spin-flavor structure is dropped, a phase of baryonic matter exists with a density of 2Nf times that for the restricted case but with the same energy (where Nf is the number of degenerate flavors). It is shown that this phase is at least metastable.Comment: 19 page

    The effects of suxamethonium and pancuronium on the haemodynamic response to endotracheal intubation

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    The pharmacological effects of suxamethonium and pancuronium on the cardiovascular system may vary and therefore alter the haemodynamic response to intubation. The arterial blood pressure, the heart rate and the rate pressure product were measured as parameters of haemodynamic change in forty adult ASA. I and II patients undergoing laryngoscopy and endotracheal intubation in a randomised controlled study. The patients were induced with either thiopentone/suxamethonium (Group A) or thiopentone/pancuronium (Group B). There was no significant difference between the groups on comparison of systolic and diastolic blood pressure changes. Pancuronium, however, caused a significantly higher rise in the heart rate after endotracheal intubation compared to suxamethonium. In both groups the maximum rate pressure product occurred one minute after intubation, rising by 56% in the suxamethonium group and 64% in the pancuronium group compared to control values. In conclusion, there were significant and statistically similar increases in systolic and diastolic blood pressures and rate pressure product following intubation in both groups with values significantly above baseline until three minutes post intubation but the increase in heart rate in group A was significantly less than that in group B

    Nonfactorization and Color-Suppressed B→ψ(ψ(2S))+K(K∗)B \to \psi (\psi(2S))+K(K^*) Decays

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    Using Nc=3N_c=3 value of the parameter a2=0.09a_2=0.09 but including a modest nonfactorized amplitude, we show that it is possible to understand all data, including polarization, for color-suppressed B→ψ(ψ(2S))+K(K∗)B\to\psi(\psi(2S))+K(K^*) decays in all commonly used models of form factors. We show that for B→ψ+KB\to\psi +K decay one can define an effective a2 a_2, which is process-dependent and, in general, complex; but it is not possible to define an effective a2a_2 for B→ψ+K∗B\to\psi +K^* decay. We also explain why nonfactorized amplitudes do not play a significant role in color-favored B decays.Comment: 13 pages, Latex, one figure (not included

    Ground State Spin Structure of Strongly Interacting Disordered 1D Hubbard Model

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    We study the influence of on-site disorder on the magnetic properties of the ground state of the infinite U 1D Hubbard model. We find that the ground state is not ferromagnetic. This is analyzed in terms of the algebraic structure of the spin dependence of the Hamiltonian. A simple explanation is derived for the 1/N periodicity in the persistent current for this model.Comment: 3 pages, no figure

    Experience with larangeal mask airway in Pakistani patients

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    One hundred and thirty seven adult patients undergoing peripheral surgery were studied regarding ease of larangeal mask airway (LMA) insertion, airway maintenance during surgery and complication encountered during insertion, maintenance and in the postoperative period. In a majority (84%) of patients, the airway was positioned correctly at the first attempt, 3% patients had mild laryngospasm at insertion and in 85% a good airway was obtained. No airway related problems were encountered intraoperatively. Two percent patients had laryngospasm on removal of LMA. Postoperatively, the complaint of sore throat and uvular trauma was seen in 4% cases
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