4,468 research outputs found
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
INVESTIGATION OF POLISHING METHODS AND SURFACE ANALYSIS AFTER MACHINING \u3cem\u3eAISI 4140\u3c/em\u3e ALLOY STEEL
AISI 4140 alloy steel has been a very common material to be investigated in automotive and aerospace industries for several decades. AISI 4140 alloy steel is chromium, molybdenum, and manganese containing low alloy steel. It has high fatigue strength, abrasion and impact resistance, toughness, and torsional strength. The functional performance is largely determined by the surface states after machining.
The aim of the present study is to explore the polishing methods and surface analysis after machining AISI 4140 alloy steel in different cutting speeds and cooling conditions. The surface analysis includes surface roughness, hardness and residual stresses. Compared to traditional polishing, an innovative experimental work was conducted on electro-polishing technology for removing surface layer before subsurface residual stress measurement.
The results of this work show that the electro-polishing method is a significant approach for the residual stress analysis. High cutting speed and cooling conditions can improve the surface quality to achieve lower surface roughness, higher microhardness and more compressive residual stresses after machining AISI 4140 alloy steel
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
Games on graphs: A minor modification of payoff scheme makes a big difference
Various social dilemma games that follow different strategy updating rules
have been studied on many networks.The reported results span the entire
spectrum, from significantly boosting,to marginally affecting,to seriously
decreasing the level of cooperation.Experimental results that are qualitatively
different from theoretical prediction have also been reported.It is widely
believed that the results are largely determined by three elements,including
payoff matrices of the underlying 2*2 games,the way that the strategic states
of the players are updated and the structure of the networks.Here we discuss
the impact of a seemly non-essential mechanism -- what we refer to as a "payoff
scheme". Specifically, in each round after the states of all of the players are
determined,the payoff scheme is how each player's payoff is calculated.In
addition to the two conventions in which either the accumulated or the averaged
payoff is calculated from playing with all of the neighboring players,we here
study the effects of calculating the payoff from pairing up with one random
player from among the neighboring players. Based on probability theory, in a
situation of uncorrelated events, the average payoff that involves all of the
neighbors should,in principal,be equivalent to the payoff from pairing up with
one neighbor.However,our simulation of games on graphs shows that, in many
cases,the two payoff schemes lead to qualitatively different levels of
cooperation.This finding appears to provide a possible explanation for a wide
spectrum of observed behaviors in the literature.We have also observed that
results from the randomly-pairing-one mechanism are more robust than the
involving-all-neighbours mechanism because,in the former case, neither the
other three main elements nor the initial states of the players have a large
impact on the final level of cooperation compared with in the latter case.Comment: 23 pages,171 figure
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