1,718 research outputs found
Discovery potential of Higgs boson pair production through 4+ final states at a 100 TeV collider
We explore the discovery potential of Higgs pair production at a 100 TeV
collider via full leptonic mode. The same mode can be explored at the LHC when
Higgs pair production is enhanced by new physics. We examine two types of fully
leptonic final states and propose a partial reconstruction method. The
reconstruction method can reconstruct some kinematic observables. It is found
that the variable determined by this reconstruction method and the
reconstructed visible Higgs mass are important and crucial to discriminate the
signal and background events. It is also noticed that a new variable, denoted
as which is defined as the mass difference of two possible
combinations, is very useful as a discriminant. We also investigate the
interplay between the direct measurements of couplings and other
related couplings and trilinear Higgs coupling at hadron colliders and
electron-positron colliders
Efficient Numerical Evaluation of Feynman Integral
Feynman loop integrals are a key ingredient for the calculation of higher
order radiation effects, and are responsible for reliable and accurate
theoretical prediction. We improve the efficiency of numerical integration in
sector decomposition by implementing a quasi-Monte Carlo method associated with
the CUDA/GPU technique. For demonstration we present the results of several
Feynman integrals up to two loops in both Euclidean and physical kinematic
regions in comparison with those obtained from FIESTA3. It is shown that both
planar and non-planar two-loop master integrals in the physical kinematic
region can be evaluated in less than half a minute with
accuracy, which makes the direct numerical approach viable for precise
investigation of higher order effects in multi-loop processes, e.g. the
next-to-leading order QCD effect in Higgs pair production via gluon fusion with
a finite top quark mass.Comment: 8 pages, 5 figures, published in Chinese Physics
Higgs Pair Production: Improved Description by Matrix Element Matching
Higgs pair production is crucial for measuring the Higgs boson self-coupling.
The dominant channel at hadron colliders is gluon fusion via heavy-quark loops.
We present the results of a fully exclusive simulation of gluon fusion Higgs
pair production based on the matrix elements for hh + 0, 1 partons including
full heavy-quark loop dependence, matched to a parton shower. We examine and
validate this new description by comparing it with (a) Higgs Effective Theory
predictions, (b) exact hh + 0-parton sample showered by pythia, and (c) exact
hh+1-parton distributions, by looking at the most relevant kinematic
distributions, such as PTh, PThh, Mhh spectra, and jet rate as well. We find
that matched samples provide an state-of-the-art accurate exclusive description
of the final state. The relevant LHE files for Higgs pair productions at the
LHC can be accessed via http://hepfarm02.phy.pku.edu.cn/foswiki/CMS/HH, which
can be used for relevant experimental analysis.Comment: accepted version in Phys. Rev. D. arXiv admin note: substantial text
overlap with arXiv:1110.172
Detecting interactions between dark matter and photons at high energy colliders
We investigate the sensitivity to the effective operators describing
interactions between dark matter particles and photons at future high energy
colliders via the \gamma+ \slashed{E} channel. Such operators could
be useful to interpret the potential gamma-ray line signature observed by the
Fermi-LAT. We find that these operators can be further tested at
colliders by using either unpolarized or polarized beams. We also derive a
general unitarity condition for processes and apply it to the dark
matter production process .Comment: 13 pages, 8 figure
Probing triple-Higgs productions via decay channel at a 100 TeV hadron collider
The quartic self-coupling of the Standard Model Higgs boson can only be
measured by observing the triple-Higgs production process, but it is
challenging for the Large Hadron Collider (LHC) Run 2 or International Linear
Collider (ILC) at a few TeV because of its extremely small production rate. In
this paper, we present a detailed Monte Carlo simulation study of the
triple-Higgs production through gluon fusion at a 100 TeV hadron collider and
explore the feasibility of observing this production mode. We focus on the
decay channel , investigating
detector effects and optimizing the kinematic cuts to discriminate the signal
from the backgrounds. Our study shows that, in order to observe the Standard
Model triple-Higgs signal, the integrated luminosity of a 100 TeV hadron
collider should be greater than ab. We also explore the
dependence of the cross section upon the trilinear () and quartic
() self-couplings of the Higgs. We find that, through a search in
the triple-Higgs production, the parameters and can be
restricted to the ranges and , respectively. We also
examine how new physics can change the production rate of triple-Higgs events.
For example, in the singlet extension of the Standard Model, we find that the
triple-Higgs production rate can be increased by a factor of .Comment: 33 pages, 11 figures, added references, corrected typos, improved
text, affiliation is changed. This is the publication versio
Constraining rare B decays by at future lepton colliders
Motivated by the recent rare B decays measurements, we study the matching
procedure of operators in the low energy effective Hamiltonian
and operators in the Standard Model effective theory (SMEFT). It is noticed
that there are more related operators in the SMEFT whose coefficients can not
be determined only from the low-energy data from B physics. We demonstrate how
to determine these coefficients with some new physics models, like
model and leptoquark models, and then consider how to probe these operators of
SMEFT at high energy by using the process at future muon
colliders, which can provide complementary information except for on the underlying models which lead to rare B decay processes. We
perform a Monte Carlo study (a hadron level analysis) to show how to separate
the signal events from the SM background events and estimate the sensitivity to
the Wilson coefficients for different models.Comment: 29 pages, 8 figures, 3 tables, added references, publication versio
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