3,898 research outputs found
Transitions in the Standard Model Effective Field Theory
The anomalies observed in decays
have attracted much attention in recent years. In this paper, we study the
, , , , and decays, all
being mediated by the same quark-level transition, in the
Standard Model Effective Field Theory. The most relevant dimension-six
operators for these processes are , , ,
and in the Warsaw basis. Evolution of the corresponding Wilson
coefficients from the new physics scale ~TeV down to the
characteristic scale is performed at three-loop in QCD and
one-loop in EW/QED. It is found that, after taking into account the constraint
, a single
or
can still be used to resolve the
anomalies at , while a single
is already ruled out by the
measured at more than . By minimizing the
function constructed based on the current data on ,
, , , and , we obtain eleven most
trustworthy scenarios, each of which can provide a good explanation of the
anomalies at . To further discriminate these different
scenarios, we predict thirty-one observables associated with the processes
considered under each NP scenario. It is found that most of the scenarios can
be differentiated from each other by using these observables and their
correlations.Comment: 43 pages, 3 figures and 5 tables; references updated and more
discussions added, final version to be published in the journa
Revisiting the -physics anomalies in -parity violating MSSM
In recent years, several deviations from the Standard Model predictions in
semileptonic decays of -meson might suggest the existence of new physics
which would break the lepton-flavour universality. In this work, we have
explored the possibility of using muon sneutrinos and right-handed sbottoms to
solve these -physics anomalies simultaneously in -parity violating
minimal supersymmetric standard model. We find that the photonic penguin
induced by exchanging sneutrino can provide sizable lepton flavour universal
contribution due to the existence of logarithmic enhancement for the first
time. This prompts us to use the two-parameter scenario to explain anomaly. Finally, the
numerical analyses show that the muon sneutrinos and right-handed sbottoms can
explain and anomalies simultaneously,
and satisfy the constraints of other related processes, such as decays, mixing, decays, as well as
, , , , , , and decays.Comment: 10 pages, 8 figures, matches to the version published in EPJ
Three-dimensional numerical study of flow characteristic and membrane fouling evolution in an enzymatic membrane reactor
In order to enhance the understanding of membrane fouling mechanism, the
hydrodynamics of granular flow in a stirred enzymatic membrane reactor was
numerically investigated in the present study. A three-dimensional Euler-Euler
model, coupled with k-e mixture turbulence model and drag function for
interphase momentum exchange, was applied to simulate the two-phase
(fluid-solid) turbulent flow. Numerical simulations of single- or two-phase
turbulent flow under various stirring speed were implemented. The numerical
results coincide very well with some published experimental data. Results for
the distributions of velocity, shear stress and turbulent kinetic energy were
provided. Our results show that the increase of stirring speed could not only
enlarge the circulation loops in the reactor, but it can also increase the
shear stress on the membrane surface and accelerate the mixing process of
granular materials. The time evolution of volumetric function of granular
materials on the membrane surface has qualitatively explained the evolution of
membrane fouling.Comment: 10 panges, 8 figure
A systematic review and meta-analysis of clinical outcomes of vitrectomy with or without intravitreal bevacizumab pretreatment for severe diabetic retinopathy
Mixing and Decay in the NMSSM with the Flavour Expansion Theorem
In this paper, motivated by the observation that the Standard Model
predictions are now above the experimental data for the mass difference , we perform a detailed study of mixing and
decay in the -invariant NMSSM with non-minimal
flavour violation, using the recently developed procedure based on the Flavour
Expansion Theorem, with which one can perform a purely algebraic mass-insertion
expansion of an amplitude written in the mass eigenstate basis without
performing any diagrammatic calculations in the interaction/flavour basis.
Specifically, we consider the finite orders of mass insertions for neutralinos
but the general orders for squarks and charginos, under two sets of assumptions
for the squark flavour structures (\textit{i.e.}, while the flavour-conserving
off-diagonal element is kept in both of these two
sectors, only the flavour-violating off-diagonal elements
and () are kept in the
\text{LL} and \text{RR} sectors, respectively). Our analytic results are then
expressed directly in terms of the initial Lagrangian parameters in the
interaction/flavour basis, making it easy to impose the experimental bounds on
them. It is found numerically that the NMSSM effects with the above two
assumptions for the squark flavour structures can accommodate the observed
deviation for , while complying with the experimental
constraints from the branching ratios of and decays.Comment: 48 pages, 7 figures, and 2 tables; More discussions and references
added, final version to be published in JHE
Comparison of the Immunoregulatory Function of Different Constituents in Radix Astragali and Radix Hedysari
Radix Astragali (RA), known as “Huangqi” in China, is one of the most popular herbal medicines known worldwide to reinforce “Qi”. RA is traditionally prepared from the dried roots of Astragalus membranaceus (MJHQ) and A. membranaceus var. mongholicus (MGHQ). Radix Hedysari is named “Hongqi” (HQ), which is similar to RA. We assessed and compared the chemical constituents and bioactivity of RA and HQ. Different constituents were extracted into five major parts and were analyzed using different methods. Comparison of the immunological effects of extracts was done by using two immunological models. Results showed that flavonoids and saponins present in RA and HQ were not only structurally significantly different but also different in their immunological effect. Amino acids extract (AE) in MGHQ shows immunological effect while AE in MJHQ and HQ did not. Polysaccharides comprised the major constituents in RA and HQ. All polysaccharides extract (PE) of the three herbs showed similar levels of immunological effect in both immunological assays
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