168 research outputs found
The strong decays of K1 resonances
We investigate the K1--> K pi pi strong interaction decays. Using the 3P0
quark-pair-creation model to derive the basic parametrization, we discuss in
detail how to obtain the various partial wave amplitudes into the possible
quasi-two-body decay channels as well as their relative phases from the
currently available experimental data. We obtain the K1 mixing angle to be
thetaK1= 60 deg, in agreement with previous works. Our study can be applied to
extract the information needed for the photon polarization determination of the
radiative B--> K1 gamma decay.Comment: 57 pages, 10 figure
vs.
Recent experimental results for the ratio of the branching fractions of and decays
came as a surprise and lead to a discussion of possibility to constraining New
Physics through these modes. Here we focus on and argue that the result is
consistent with the Standard Model within , and that the test of
compatibility of this ratio with the Standard Model can be done experimentally
with a minimal theory input. We also show that these two decay channels can
provide us with quite good constraints of the New Physics couplings.Comment: 10 pages (published version
Preparing a commercial quantum key distribution system for certification against implementation loopholes
A commercial quantum key distribution (QKD) system needs to be formally
certified to enable its wide deployment. The certification should include the
system's robustness against known implementation loopholes and attacks that
exploit them. Here we ready a fiber-optic QKD system for this procedure. The
system has a prepare-and-measure scheme with decoy-state BB84 protocol,
polarisation encoding, qubit source rate of 312.5 MHz, and is manufactured by
QRate in Russia. We detail its hardware and post-processing. We analyse the
hardware for any possible implementation loopholes and discuss countermeasures.
We then amend the system design to address the highest-risk loopholes
identified. We also work out technical requirements on the certification lab
and outline its possible structure.Comment: 33 pages, 11 figures, 2 table
Impact of on the New Physics search in decay
We discuss the uncertainty related to the amount of unwanted events in the sample of .
Those events can increase the measured differential decay rate by up to 10% in
the low region, and can be a source of non-negligible uncertainty in the
full angular distribution of the decay.
Although the transverse asymmetries should be unaffected by the presence of the
-wave pairs, coming from the scalar meson, we show that in
practice their normalization might be sensitive to those events and could
entail a sizable uncertainty in transverse asymmetries around .
For other 's that error is under about 10%.Comment: 16 pages [as published in NPB
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