1,382 research outputs found
The NLO contributions to the scalar pion form factors and the annihilation corrections to the decays
In this paper, by employing the factorization theorem, we made the
first calculation for the space-like scalar pion form factor at
the leading order (LO) and the next-to-leading order (NLO) level, and then
found the time-like scalar pion form factor by analytic
continuation from the space-like one. From the analytical evaluations and the
numerical results, we found the following points: (a) the NLO correction to the
space-like scalar pion form factor has an opposite sign with the LO one but is
very small in magnitude, can produce at most decrease to LO result in
the considered region; (b) the NLO time-like scalar pion form factor
describes the contribution to the
factorizable annihilation diagrams of the considered decays,
i.e. the NLO annihilation correction; (c) the NLO part of the form factor
is very small in size, and is almost independent with the
variation of cutoff scale , but this form factor has a large strong
phase around and may play an important role in producing large CP
violation for decays; and (d) for and decays, the newly known NLO annihilation correction can produce
only a very small enhancement to their branching ratios, less than in
magnitude, and therefore we could not interpret the well-known -puzzle
by the inclusion of this NLO correction to the factorizable annihilation
diagrams.Comment: 26 pages, 12 figures, 1 Table; Minor correction
Probing dark particles indirectly at the CEPC
When dark matter candidate and its parent particles are nearly degenerate, it
would be difficult to probe them at the Large Hadron Collider directly. We
propose to explore their quantum loop effects at the CEPC through the golden
channel process . We use a renormalizable toy model
consisting of a new scalar and a fermion to describe new physics beyond the
Standard Model. The new scalar and fermion are general multiplets of the
symmetry, and couple to the muon lepton through Yukawa
interaction. We calculate their loop contributions to anomalous
and couplings which can be applied to many new
physics models. The prospects of their effects at the CEPC are also examined
assuming a 0.002 accuracy in the cross section measurement
Production of charged meson in bottom hadron charmed decays and the effect of the finite width correction of the meson
We calculate the branching ratio of a bottom hadron decaying into a charmed
hadron and a charged meson within the QCD factorization approach. We
consider the effect of the finite width correction of the meson. Our
numerical calculation shows an obvious correction because of this effect. We
find that the finite width effect of the meson reduces the branching
ratios by about 9% to 11% for bottom meson decay channels:
, , and , and
increases the branching ratio by about 10% for
.Comment: 12 page
Current situation and countermeasures of port logistics park information construction
Purpose: Improve work efficiency of logistics park department, and drive the economy of the park and its surrounding areas.
Design/methodology/approach: Analyze the information development situation and existent questions of current national logistics park, and design proper scheme to meet the demand of port logistics park.
Findings: Proposed an information construction implementation plan using technology of the Internet of things which can be applied to port logistics park. Designed a scheme for the park information construction and explained the system's implementation strategy and implementation steps.
Practical implications: The proposed construction program is particularly suitable for the northwest port logistics parks in China, and also has reference function to other logistics park construction.
Originality/value: Group the information construction of the logistics park into four levels, three types of users, and two requirements. The scheme is innovative and comprehensive, which can ensure the development of port logistics park.Peer Reviewe
A novel arabinose-inducible genetic operation system developed for Clostridium cellulolyticum
<p>
Background: Clostridium cellulolyticum and other cellulolytic Clostridium strains are natural producers of lignocellulosic biofuels and chemicals via the consolidated bioprocessing (CBP) route, and systems metabolic engineering is indispensable to meet the cost-efficient demands of industry. Several genetic tools have been developed for Clostridium strains, and an efficient and stringent inducible genetic operation system is still required for the precise regulation of the target gene function.</p
- …