660 research outputs found
Half-life Expectations for Neutrinoless Double Beta Decay in Standard and Non-Standard Scenarios
We investigate the half-life expectations for neutrinoless double beta decay
by applying statistical distributions of neutrino mixing observables, neutrino
mass constraints from cosmology and nuclear matrix elements. The analysis is
performed in the standard scenario of active Majorana neutrino exchange, when
light sterile neutrinos are added, and within TeV-scale left-right symmetric
frameworks. The latter two cases correspond to a modified phenomenology of
double beta decay for a normal and inverted mass ordering, and thus different
discovery potential for future experiments.Comment: 18 pages, 10 figures, and 4 table
Associated Production of Fermionic Dark Matter and Neutrino at the Future Lepton Colliders
In light of the fermionic dark matter absorption on electron target that can
be observed by direct detection experiments, we study its complementary
searches at the future colliders such as CEPC, FCC-ee, ILC, and CLIC.
Two typical processes, the mono-photon and electron-positron pair production
associated with missing energy, can serve the purpose. While the mono-photon
search prevails at CEPC, FCC-ee, and ILC, the channel
has more significant contributions at CLIC with much higher collision energy
. The beam polarizations can help further suppressing the SM
backgrounds to enhance the signal significance while differential cross
sections can distinguish the Lorentz structure of various effective operators.
The combined sensitivity can reach well above 1 TeV at CEPC/FCC-ee and ILC
while it further touches 30 TeV at CLIC. Comparing with the updated results
from the dark matter direct detection experiments (XENON1T, PandaX-II,
PandaX-4T, LZ, and XENONnT), astrophysical observations, and
cosmological constraints, the collider searches can not just provide better
sensitivity for light dark matter mass but also scan much wider mass range.Comment: 34pages, 17 captioned figure
W boson mass in the NP models with extra gauge group
The precise measurement of the W boson mass is closely related to the
contributions of new physics (NP), which can significantly constrain the
parameter space of NP models, particularly those with an additional
local gauge group. The inclusion of a new gauge boson and gauge couplings
in these models can contribute to the oblique parameters , , and W
boson mass at tree level. Taking into account the effects of kinetic mixing, we
calculate and analyze the oblique parameters , , and W boson mass in
such NP models in this study. It is found that the kinetic mixing effects can
make significant contributions to the W boson mass, which can satisfy the
recently measured W boson mass at CDF II or ATLAS by choosing appropriate
values of gauge coupling constants and extra group charges of leptons or
scalar doublets. In addition, if the leptonic Yukawa couplings are invariant
under the extra local gauge group, these contributions can be eliminated
by redefining the gauge boson fields through eliminating the neutral currents
involving charged leptons, even with nonzero kinetic mixing effects.Comment: 11 pages, 2 figure
Search for W-Associated Production of Single Top Quarks in CMS
The production of single top quarks at the LHC provides a unique window onto the measurement of the CKM matrix element IV_tbI without assuming 3~generation unitarity. The W-associated production of single top is a challenging channel due to the large overlap in phase space with t bar t production. We have developed a ratio method to reduce the systematic uncertainties in the presence of large t bar t backgrounds. The expected uncertainties and significance for a 60~pb pp to tW production cross section with 10 fb^-1 of CMS data are presented
Study of Periplaneta Americana Microbial Community Structure and Diversity by 16S rRNA High-Throughput Sequencing
Objective: The present study probes into the microbial community structure in Periplaneta americana under different breeding conditions, using 16S rRNA high-throughput sequencing technique, in the hope of finding the microbial community structure in Periplaneta americana and their diversity under different breeding conditions. Methods: In this study, we extract the microbial metagenomic DNA of 5 groups of Periplaneta americana which under different breeding conditions. Using lllumina Miseq sequencing platform, two-terminal sequencing of V3-V4 regions of 16S rRNA were sequenced; diversity of community structure was analyzed using the softwares such as fastqc, QIIME, PyNAST, fasttree and R language.Results: Shannon index of samples in SG group was lower than that of the other four groups, significantly lower than that of DB group (P<0.05), but not significantly different from other groups. This suggested that the intake of a mixed fodder with high sugar, high fat and high protein by Periplaneta americana can reduce the diversity of microbial communities. Our findings showed that breeding intervention with different fodders may cause differences in the contents of Bacteroidetes, Proteobacteria and Firmicutes in Periplaneta americana. Results showed that long-term intake of lots of sucrose and fat may increase the proportion of Bacteroidetes in Periplaneta americana; and long-term intake of lots of sucrose may reduce the proportion of Proteobacteria in Periplaneta americana; and long-term intake of lots of fat may reduce the proportion of Firmicutes in Periplaneta americana. Two major dominant bacterial genera in all samples were Blattabacterium and Rickettsiella. But different feeding interventions can change the proportions of Blattabacterium and Rickettsiella.Conclusion: Periplaneta americana has a complex microbial community structure. Different feeding conditions may change the microbial community structure of Periplaneta americana. An important bacterial genus in Periplaneta americana, Blattabacterium is positively correlated with the intake of sucrose- and fat-rich fodder. In the breeding process of Periplaneta americana, adding sucrose and fat to fodder may increase the content and proportion of Blattabacterium in microbial communities
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