17,767 research outputs found
CP violation effects in the diphoton spectrum of heavy scalars
In a class of new physics models, an extended Higgs sector and new
CP-violating sources are simultaneously present in order to explain the baryon
asymmetry in the Universe. The aim of this work is to study the implications of
beyond the Standard Model (SM) CP violation for the searches of heavy scalars
at the LHC. In particular, we focus on the diphoton channel searches in the
CP-violating two-Higgs-doublet model (CPV 2HDM). To have a sizable CPV in the
scalar sector, the two heavy neutral scalars in 2HDM tend to be nearly
degenerate. The theoretical constraints of unitarity, perturbativity and vacuum
stability are considered, which requires that the heavy scalars TeV in a large region of the parameter space. The experimental limits are
also taken into account, including the direct searches of heavy neutral scalars
in the final state of the SM , and bosons, the differential
data, those from the charged scalar sector which is implied by the
oblique parameter, as well as the precise measurements of the electric
dipole moments of electron and mercury. The quantum interference effects
between the resonances and the SM background are crucially important for the
diphoton signals, and the CPV mixing of the quasi-degenerate heavy scalars
could enhance significantly the resonance peak. With an integrated luminosity
of 3000 fb at the LHC, almost the whole parameter space of CPV 2HDM
could be probed in the diphoton channel, and the CPV could also be directly
detected via the diphoton spectrum.Comment: 32 pages (two columns), 20 figures, 1 table, minor changes, version
to appear in PR
Prospects for Triple Gauge Coupling Measurements at Future Lepton Colliders and the 14 TeV LHC
The production is the primary channel to directly probe the triple gauge
couplings. We first analyze the process at the
future lepton collider, China's proposed Circular Electron-Positron Collider
(CEPC). We use the five kinematical angles in this process to constrain the
anomalous triple gauge couplings and relevant dimension six operators at the
CEPC up to the order of magnitude of . The most sensible information
is obtained from the distributions of the production scattering angle and the
decay azimuthal angles. We also estimate constraints at the 14 TeV LHC, with
both 300 fb and 3000 fb integrated luminosity from the leading
lepton and azimuthal angle difference distributions in
the di-lepton channel. The constrain is somewhat weaker, up to the order of
magnitude of . The limits on the triple gauge couplings are
complementary to those on the electroweak precision observables and Higgs
couplings. Our results show that the gap between sensitivities of the
electroweak and triple gauge boson precision can be significantly decreased to
less than one order of magnitude at the 14 TeV LHC, and that both the two
sensitivities can be further improved at the CEPC.Comment: 36 pages, 5 figures, 8 tables, version to appear in JHE
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Twin roll casting and melt conditioned twin-roll casting of magnesium alloys
Recently, BCAST at Brunel University has developed a MCAST (melt conditioning by advanced shear technology) process for conditioning liquid metal at temperature either above or bellow the alloy liquidus using a high shear twin-screw mechanism. The MCAST process has now been combined with the twin roll casting (TRC) process to form an innovative technology, namely, the melt conditioned twin roll casting (MC-TRC) process for casting Al-alloy and Mg-alloy strips. During the MC-TRC process, liquid alloy with a specified temperature is continuously fed into the MCAST machine. By intensive shearing under the high shear rate and high intensity of turbulence, the liquid is transformed into conditioned melt with uniform temperature and composition throughout the whole volume. The conditioned melt is then fed continuously into the twin-roll caster for strip production. The experimental results show that the AZ91D MC-TRC strips with different thicknesses have fine and uniform microstructure. The strip consists of equiaxed grains with a mean size of 60-70μm. The strip displays extremely uniform grain size and composition throughout the whole cross-section. Investigation also shows that both TRC and MC-TRC processes with reduced deformation are effective to reduce the formation of defects, particularly the formation of the central line segregations
Adversarial Sparse-View CBCT Artifact Reduction
We present an effective post-processing method to reduce the artifacts from
sparsely reconstructed cone-beam CT (CBCT) images. The proposed method is based
on the state-of-the-art, image-to-image generative models with a perceptual
loss as regulation. Unlike the traditional CT artifact-reduction approaches,
our method is trained in an adversarial fashion that yields more perceptually
realistic outputs while preserving the anatomical structures. To address the
streak artifacts that are inherently local and appear across various scales, we
further propose a novel discriminator architecture based on feature pyramid
networks and a differentially modulated focus map to induce the adversarial
training. Our experimental results show that the proposed method can greatly
correct the cone-beam artifacts from clinical CBCT images reconstructed using
1/3 projections, and outperforms strong baseline methods both quantitatively
and qualitatively
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