941,576 research outputs found
Beta-Decay Correlations in the LHC Era
Neutron and nuclear beta decay correlation coefficients are linearly
sensitive to the exotic scalar and tensor interactions that are not included in
the Standard Model. The proposed experiment will measure simultaneously 11
neutron correlation coefficients (, , , , , , , , ,
, ) where 5 of them (, , , , ) were never addressed
before. Silicon pixel detectors are considered as promising alternative to
multi-wire gas chambers devoted for electron tracking in the original setup.
The expected sensitivity limits for and -- EFT
parameters describing the scalar and tensor contributions to be extracted from
the transverse electron polarization related coefficients , , , ,
, , are discussed.Comment: 8 pages, 2 figures, presented at Jagiellonian Symposium of
Fundamental and Applied Subatomic Physics, Cracow, 201
Generating functions for Wilf equivalence under generalized factor order
Kitaev, Liese, Remmel, and Sagan recently defined generalized factor order on
words comprised of letters from a partially ordered set by
setting if there is a subword of of the same length as
such that the -th character of is greater than or equal to the -th
character of for all . This subword is called an embedding of
into . For the case where is the positive integers with the usual
ordering, they defined the weight of a word to be
, and the corresponding weight
generating function . They then
defined two words and to be Wilf equivalent, denoted , if
and only if . They also defined the related generating
function where
is the set of all words such that the only embedding of
into is a suffix of , and showed that if and only if
. We continue this study by giving an explicit formula for
if factors into a weakly increasing word followed by a weakly
decreasing word. We use this formula as an aid to classify Wilf equivalence for
all words of length 3. We also show that coefficients of related generating
functions are well-known sequences in several special cases. Finally, we
discuss a conjecture that if then and must be
rearrangements, and the stronger conjecture that there also must be a
weight-preserving bijection such
that is a rearrangement of for all .Comment: 23 page
Two-Body Cabibbo-Suppressed Charmed Meson Decays
Singly-Cabibbo-suppressed decays of charmed particles governed by the quark
subprocesses and are analyzed using a
flavor-topology approach, based on a previous analysis of the Cabibbo-favored
decays governed by . Decays to and , where is a
pseudoscalar meson and is a vector meson, are considered. We include
processes in which and are produced.Comment: 18 pages, latex, 2 figures, to be submitted to Phys. Rev.
U(n) Spectral Covers from Decomposition
We construct decomposed spectral covers for bundles on elliptically fibered
Calabi-Yau threefolds whose structure groups are S(U(1) x U(4)), S(U(2) x U(3))
and S(U(1) x U(1) x U(3)) in heterotic string compactifications. The
decomposition requires not only the tuning of the SU(5) spectral covers but
also the tuning of the complex structure moduli of the Calabi-Yau threefolds.
This configuration is translated to geometric data on F-theory side. We find
that the monodromy locus for two-cycles in K3 fibered Calabi-Yau fourfolds in a
stable degeneration limit is globally factorized with squared factors under the
decomposition conditions. This signals that the monodromy group is reduced and
there is a U(1) symmetry in a low energy effective field theory. To support
that, we explicitly check the reduction of a monodromy group in an appreciable
region of the moduli space for an gauge theory with (1+2) decomposition.
This may provide a systematic way for constructing F-theory models with U(1)
symmetries.Comment: 41 pages, 14 figures; v2: minor improvements and a reference adde
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