311 research outputs found
Three Numerical Puzzles and the Top Quark's Chiral Weak-Moment
Versus the standard model's t --> W b decay helicity amplitudes, three
numerical puzzles occur at the 0.1 % level when one considers the amplitudes in
the case of an additional (f_M + f_E) coupling of relative strength 53 GeV. The
puzzles are theoretical ones which involve the t --> W b decay helicity
amplitudes in the two cases, the relative strength of this additional coupling,
and the observed masses of these three particles. A deeper analytic realization
is obtained for two of them. Equivalent realizations are given for the
remaining one. An empirical consequence of these analytic realizations is that
it is important to search for effects of a large chiral weak-moment of the
top-quark, the effective mass-scale is about 53 GeV. A full theoretical
resolution would include relating the origin of such a chiral weak-moment and
the mass generation of the top-quark, the W-boson, and probably the b-quark.Comment: 18 pages, 1 postscript table (revised to better explain notation,
model #1, add a little material...
Book Reviews
Reviews of the following books: The Long Argument: English Puritanism and the Shaping of New England Culture, 1570-1700 by Stephen Foster; The Salem Witch Crisis by Larry Gragg; A Home for Everyman: The Greek Revival and Maine Domestic Architecture by Joyce K. Bibber; The Gunpowder Mills of Maine by Maurice W. Hitten; In the Hands of Providence: Joshua L. Chamberlain And The American Civil War by Alice Rains Trulock; Hurricane Island: The Town That Disappeared by Eleanor Motley Richardson; Home Front On Penobscot Bay: Rockland During The War Years, 1940-1945by Paul G. Merriam, Thomas J. Molloy, and Theodore W. Sylvester, Jr.; The History of Broadcasting in Maine: The First Fifty Yearsby Ellie Thompson; New Compass Points by Roy P. Fairfiel
Graphical amplitudes from SCET
We discuss the relationship between the graphical amplitudes T, C, P, ...
used to parameterize nonleptonic B decay amplitudes, and matrix elements of
operators in the soft-collinear effective theory (SCET) at leading order in
\Lambda/m_b. Using the SU(3) flavor symmetry of the weak Hamiltonian we derive
all-order constraints on the electroweak penguin contributions to the Wilson
coefficients of SCET operators.Comment: 7 pages; one additional relation included, minor corrections. version
published in Physics Letters
A new CP violating observable for the LHC
We study a new type of CP violating observable that arises in three body
decays that are dominated by an intermediate resonance. If two interfering
diagrams exist with different orderings of final state particles, the required
CP-even phase arises due to the different virtualities of the resonance in each
of the two diagrams. This method can be an important tool for accessing new CP
phases at the LHC and future colliders.Comment: 22 pages, v2: discussion of charged particle decays and a few
references added v3: typos corrected, matches published versio
Site-Specific Metal Chelation Facilitates the Unveiling of Hidden Coordination Sites in an Fe II/Fe III -Seamed Pyrogallol[4]arene Nanocapsule
Under suitable conditions, C-alkylpyrogallol[4]arenes
(PgCs) arrange into spherical metal–organic nanocapsules (MONCs)
upon coordination to appropriate metal ions. Herein we present the
synthesis and structural characterization of a novel FeII/FeIII-seamed MONC, as well as studies related to its
electrochemical and magnetic behaviors. Unlike other MONCs that are
assembled through 24 metal ions, this nanocapsule comprises 32 Fe
ions, uncovering 8 additional coordination sites situated between
the constituent PgC subunits. The FeII ions are likely
formed by the reducing ability of DMF used in the synthesis, representing
a novel synthetic route toward polynuclear mixed-valence MONCs
Rare radiative B decays to orbitally excited K mesons
The exclusive rare radiative B meson decays to orbitally excited axial-vector
mesons K_1^*(1270), K_1(1400) and to the tensor meson K_2^*(1430) are
investigated in the framework of the relativistic quark model based on the
quasipotential approach in quantum field theory. These decays are considered
without employing the heavy quark expansion for the s quark. Instead the s
quark is treated to be light and the expansion in inverse powers of the large
recoil momentum of the final K^{**} meson is used to simplify calculations. It
is found that the ratio of the branching fractions of rare radiative B decays
to axial vector K^*_1(1270) and K_1(1400) mesons is significantly influenced by
relativistic effects. The obtained results for B decays to the tensor meson
K_2^*(1430) agree with recent experimental data from CLEO.Comment: 17 pages, revte
Sustainment of the TeleSleep program for rural veterans
BackgroundIn fiscal year 2021, the Veterans Health Administration (VHA) provided care for sleep disorders to 599,966 Veterans, including 189,932 rural Veterans. To further improve rural access, the VA Office of Rural Health developed the TeleSleep Enterprise-Wide Initiative (EWI). TeleSleep's telemedicine strategies include tests for sleep apnea at the Veteran's home rather than in a sleep lab; Clinical Video Telehealth applications; and other forms of virtual care. In 2017 and 2020, VHA provided 3-year start-up funding to launch new TeleSleep programs at rural-serving VA medical facilities.MethodsIn early 2022, we surveyed leaders of 24 sites that received TeleSleep funding to identify successes, failures, facilitators, and barriers relevant to sustaining TeleSleep implementations upon expiration of startup funding. We tabulated frequencies on the multiple choice questions in the survey, and, using the survey's critical incident framework, summarized the responses to open-ended questions. TeleSleep program leaders discussed the responses and synthesized recommendations for improvement.Results18 sites reported sustainment, while six were “on track.” Sustainment involved medical centers or regional entities incorporating TeleSleep into their budgets. Facilitators included: demonstrating value; aligning with local priorities; and collaborating with spoke sites serving rural Veterans. Barriers included: misalignment with local priorities; and hiring delays. COVID was a facilitator, as it stimulated adoption of telehealth practices; and also a barrier, as it consumed attention and resources. Recommendations included: longer startup funding; dedicated funding for human resources to accelerate hiring; funders communicating with local facility leaders regarding how TeleSleep aligns with organizational priorities; hiring into job classifications aligned with market pay; and obtaining, from finance departments, projections and outcomes for the return on investment in TeleSleep
On leptonic models for blazars in the Fermi era
Some questions raised by Fermi-LAT data about blazars are summarized, along
with attempts at solutions within the context of leptonic models. These include
both spectral and statistical questions, including the origin of the GeV breaks
in low-synchrotron peaked blazars, the location of the gamma-ray emission
sites, the correlations in the spectral energy distributions with luminosity,
and the difficulty of synchrotron/SSC models to fit the spectra of some TeV
blazars.Comment: 9 pages, 1 figure, in "Beamed and Unbeamed Gamma Rays from Galaxies,"
Muonio, Finland, 11-15 April, 2011, ed. R. Wagner, L. Maraschi, A. Sillanpaa,
to appear in Journal of Physics: Conference Serie
Gamma-ray Activity in the Crab Nebula: The Exceptional Flare of April 2011
The Large Area Telescope on board the Fermi satellite observed a gamma-ray
flare in the Crab nebula lasting for approximately nine days in April of 2011.
The source, which at optical wavelengths has a size of ~11 ly across, doubled
its gamma-ray flux within eight hours. The peak photon flux was (186 +- 6) 10-7
cm-2 s-1 above 100 MeV, which corresponds to a 30-fold increase compared to the
average value. During the flare, a new component emerged in the spectral energy
distribution, which peaked at an energy of (375 +- 26) MeV at flare maximum.
The observations imply that the emission region was likely relativistically
beamed toward us and that variations in its motion are responsible for the
observed spectral variability.Comment: 13 pages, 7 figures, accepted for publication in Ap
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