814 research outputs found
Mirror matter admixtures in K_S to gamma gamma
The latest measurement of the K_S to gamma gamma branching ratio clearly
shows an enhancement over the current theoretical prediction. As in other K and
B meson decays, this invites to consider the possibility of the contribution of
new physics. We study a particular form of the latter, which may be referred to
as manifest mirror symmetry. The experimental data are described using
previously determined values for the mixing angles of the admixtures of mirror
matter in ordinary hadrons and by assuming that for pi^0, eta, eta', the mirror
decay amplitudes have the same magnitudes as their ordinary counterparts
Recursive parametrization of Quark flavour mixing matrices
We examine quark flavour mixing matrices for three and four generations using
the recursive parametrization of and matrices developed by some
of us in Refs.[2] and [3]. After a brief summary of the recursive
parametrization, we obtain expressions for the independent rephasing invariants
and also the constraints on them that arise from the requirement of mod
symmetry of the flavour mixing matrix
Bounds on quark mass matrices elements due to measured properties of the mixing matrix and present values of the quark masses
We obtain constraints on possible structures of mass matrices in the quark
sector by using as experimental restrictions the determined values of the quark
masses at the energy scale, the magnitudes of the quark mixing matrix
elements , , , and , and the
Jarlskog invariant . Different cases of specific mass matrices are
examined in detail. The quality of the fits for the Fritzsch and Stech type
mass matrices is about the same with and
, respectively. The fit for a simple
generalization (one extra parameter) of the Fritzsch type matrices, in the
physical basis, is much better with . For
comparison we also include the results using the quark masses at the 2 GeV
energy scale. The fits obtained at this energy scale are similar to that at
energy scale, implying that our results are unaffected by the evolution
of the quark masses from 2 to 91 GeV.Comment: Evolution effects include
Synthesizing Imperative Programs from Examples Guided by Static Analysis
We present a novel algorithm that synthesizes imperative programs for
introductory programming courses. Given a set of input-output examples and a
partial program, our algorithm generates a complete program that is consistent
with every example. Our key idea is to combine enumerative program synthesis
and static analysis, which aggressively prunes out a large search space while
guaranteeing to find, if any, a correct solution. We have implemented our
algorithm in a tool, called SIMPL, and evaluated it on 30 problems used in
introductory programming courses. The results show that SIMPL is able to solve
the benchmark problems in 6.6 seconds on average.Comment: The paper is accepted in Static Analysis Symposium (SAS) '17. The
submission version is somewhat different from the version in arxiv. The final
version will be uploaded after the camera-ready version is read
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