15,745 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
Optimizing Average-Maximum TTR Trade-off for Cognitive Radio Rendezvous
In cognitive radio (CR) networks, "TTR", a.k.a. time-to-rendezvous, is one of
the most important metrics for evaluating the performance of a channel hopping
(CH) rendezvous protocol, and it characterizes the rendezvous delay when two
CRs perform channel hopping. There exists a trade-off of optimizing the average
or maximum TTR in the CH rendezvous protocol design. On one hand, the random CH
protocol leads to the best "average" TTR without ensuring a finite "maximum"
TTR (two CRs may never rendezvous in the worst case), or a high rendezvous
diversity (multiple rendezvous channels). On the other hand, many
sequence-based CH protocols ensure a finite maximum TTR (upper bound of TTR)
and a high rendezvous diversity, while they inevitably yield a larger average
TTR. In this paper, we strike a balance in the average-maximum TTR trade-off
for CR rendezvous by leveraging the advantages of both random and
sequence-based CH protocols. Inspired by the neighbor discovery problem, we
establish a design framework of creating a wake-up schedule whereby every CR
follows the sequence-based (or random) CH protocol in the awake (or asleep)
mode. Analytical and simulation results show that the hybrid CH protocols under
this framework are able to achieve a greatly improved average TTR as well as a
low upper-bound of TTR, without sacrificing the rendezvous diversity.Comment: Accepted by IEEE International Conference on Communications (ICC
2015, http://icc2015.ieee-icc.org/
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