3,501 research outputs found
Exclusive Lambda_b -> Lambda l^+ l^- decay in two Higgs doublet model
Rare Lambda_b -> Lambda l^+ l^- decay is investigated in framework of general
two Higgs doublet model, in which a new source of CP violation exists (model
III). The polarization parameter, CP asymmetry and decay width are calculated.
It is shown that CP asymmetry is a very sensitive tool for establishing model
III.Comment: 16 pages, 3 figures, LaTeX formatte
First determination of the content of and updated determination of the contents of and
Quantum-correlated decays collected by the CLEO-c
experiment are used to perform a first measurement of , the
fractional -even content of the self-conjugate decay , obtaining a value of . An important
input to the measurement comes from the use of
and decays to tag the signal mode. This same
technique is applied to the channels and , yielding and
, where the first uncertainty is
statistical and the second systematic. These measurements are consistent with
those of an earlier analysis, based on -eigenstate tags, and can be
combined to give values of and
. The results will enable the three modes to
be included in a model-independent manner in measurements of the unitarity
triangle angle using decays, and in time-dependent
studies of violation and mixing in the system.Comment: Minor revisions following journal acceptanc
High efficiency thermionic converter studies
Research in thermionic energy conversion technology is reported. The objectives were to produce converters suitable for use in out of core space reactors, radioisotope generators, and solar satellites. The development of emitter electrodes that operate at low cesium pressure, stable low work function collector electrodes, and more efficient means of space charge neutralization were investigated to improve thermionic converter performance. Potential improvements in collector properties were noted with evaporated thin film barium oxide coatings. Experiments with cesium carbonate suggest this substance may provide optimum combinations of cesium and oxygen for thermionic conversion
Joint density-functional theory for electronic structure of solvated systems
We introduce a new form of density functional theory for the {\em ab initio}
description of electronic systems in contact with a molecular liquid
environment. This theory rigorously joins an electron density-functional for
the electrons of a solute with a classical density-functional theory for the
liquid into a single variational principle for the free energy of the combined
system. A simple approximate functional predicts, without any fitting of
parameters to solvation data, solvation energies as well as state-of-the-art
quantum-chemical cavity approaches, which require such fitting.Comment: Fixed typos and minor updates to tex
New Source of CP violation in B physics ?
In this talk we discuss how the down type left-right squark mixing in
Supersymmetry can induce a new source of CP violation in the time dependent
asymmtries in B --> phi K process. We use QCD improved factorization process to
calculate the hadronic matrix element for the process and find the allowed
parameter space for and , the magnitude and phase of the down
type LR(RL) squark mixing parameter . In the same allowed
regin we calculate the expected CP asymmtries in the
process.Comment: 16 pages, Latex, 2 postscript figures, invited talk presented by N.G.
Deshpande at the 9th Adriatic meeting, Dubrovnik, Croatia, 4-14 September,
2003. With updated reference
Use of MenACWY-CRM vaccine in children aged 2 through 23 months at increased risk for meningococcal disease: recommendations of the Advisory Committee on Immunization Practices, 2013
During its October 2013 meeting, the Advisory Committee on Immunization Practices (ACIP) recommended use of a third meningococcal conjugate vaccine, MenACWY-CRM (Menveo, Novartis), as an additional option for vaccinating infants aged 2 through 23 months at increased risk for meningococcal disease. MenACWY-CRM is the first quadrivalent meningococcal conjugate vaccine licensed for use in children aged 2 through 8 months. MenACWY-D (Menactra, Sanofi Pasteur) is recommended for use in children aged 9 through 23 months who are at increased risk for meningococcal disease, and Hib-MenCY-TT (MenHibrix, GlaxoSmithKline) is recommended for use in children aged 6 weeks through 18 months at increased risk. This report summarizes information on MenACWY-CRM administration in infants and provides recommendations for vaccine use in infants aged 2 through 23 months who are at increased risk for meningococcal disease. Because the burden of meningococcal disease in infants is low in the United States and the majority of cases that do occur are caused by serogroup B, which is not included in any vaccine licensed in the United States, only those infants who are at increased risk for meningococcal disease are recommended to receive a meningococcal vaccine
Binary systems of neutral mesons in Quantum Field Theory
Quasi-degenerate binary systems of neutral mesons of the kaon type are
investigated in Quantum Field Theory (QFT). General constraints cast by
analyticity and discrete symmetries P, C, CP, TCP on the propagator (and on its
spectral function) are deduced. Its poles are the physical masses; this
unambiguously defines the propagating eigenstates. It is diagonalized and its
spectrum thoroughly investigated. The role of ``spurious'' states, of zero norm
at the poles, is emphasized, in particular for unitarity and for the
realization of TCP symmetry. The K_L-K_S mass splitting triggers a tiny
difference between their CP violating parameters \epsilon_L and \epsilon_S,
without any violation of TCP. A constant mass matrix like used in Quantum
Mechanics (QM) can only be introduced in a linear approximation to the inverse
propagator, which respects its analyticity and positivity properties; it is
however unable to faithfully describe all features of neutral mesons as we
determine them in QFT, nor to provide any sensible parameterization of eventual
effects of TCP violation. The suitable way to diagonalize the propagator makes
use of a bi-orthogonal basis; it is inequivalent to a bi-unitary transformation
(unless the propagator is normal, which cannot occur here). Problems linked
with the existence of different ``in'' and ``out'' eigenstates are smoothed
out. We study phenomenological consequences of the differences between the QFT
and QM treatments. The non-vanishing of semi-leptonic asymmetry \delta_S -
\delta_L does not signal, unlike usually claimed, TCP violation, while A_TCP
keeps vanishing when TCP is realized. We provide expressions invariant by the
rephasing of K0 and K0bar.Comment: 44 pages, 2 figures. Version to appear in Int. J. Mod. Phys.
First determination of the CP content of D->pi+pi-pi0 and D->K+K-pi0
Quantum-correlated psi(3770)->DDbar decays collected by the CLEO-c experiment
are used to perform first measurements of F+, the fractional CP-even content of
the self-conjugate decays D->pi+pi-pi0 and D->K+K-pi0. Values of 0.968 +/-
0.017 +/- 0.006 and 0.731 +/- 0.058 +/- 0.021 are obtained for pi+pi-pi0 and
K+K-pi0, respectively. It is demonstrated how modes of this sort can be cleanly
included in measurements of the unitarity triangle angle gamma using B+/- -> D
K+/- decays. The high CP-even content of D -> pi+pi-pi0, in particular, makes
this a promising mode for improving the precision on gamma.Comment: 18 pages, 4 figures, submitted to Phys. Lett.
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