26,224 research outputs found
Nagy-Soper subtraction scheme for multiparton final states
In this work, we present the extension of an alternative subtraction scheme
for next-to-leading order QCD calculations to the case of an arbitrary number
of massless final-state partons. The scheme is based on the splitting kernels
of an improved parton shower and comes with a reduced number of final state
momentum mappings. While a previous publication including the setup of the
scheme has been restricted to cases with maximally two massless partons in the
final state, we here provide the final state real emission and integrated
subtraction terms for processes with any number of massless partons. We apply
our scheme to three jet production at lepton colliders at next-to-leading order
and present results for the differential C parameter distribution.Comment: 45 pages, 5 figures v2: several references added; v3: title changed,
references and a discussion of further scaling improvement added. Corresponds
to published journal versio
Economic Analysis of Domestic Combined Heat and Power System in the UK
A combined heat and power (CHP) system is an efficient and clean way to generate power (electricity). Heat produced by the CHP system can be used for water and space heating. The CHP system which uses hydrogen as fuel produces zero carbon emission. Its’ efficiency can reach more than 80% whereas that of a traditional power station can only reach up to 50% because much of the thermal energy is wasted. The other advantages of CHP systems include that they can decentralize energy generation, improve energy security and sustainability, and significantly reduce the energy cost to the users. This paper presents the economic benefits of using a CHP system in the domestic environment. For this analysis, natural gas is considered as potential fuel as the hydrogen fuel cell based CHP systems are rarely used. UK government incentives for CHP systems are also considered as the added benefit. Results show that CHP requires a significant initial investment in return it can reduce the annual energy bill significantly. Results show that an investment may be paid back in 7 years. After the back period, CHP can run for about 3 years as most of the CHP manufacturers provide 10 year warranty
Multiple Scattering of Fractionally-Charged Quasiparticles
We employ shot noise measurements to characterize the effective charge of
quasiparticles, at filling factor nu=1/3 of the fractional quantum Hall regime,
as they scatter from an array of identical weak backscatterers. Upon
scattering, quasiparticles are known to bunch, e.g., only three e/3 charges, or
'electrons' are found to traverse a rather opaque potential barrier. We find
here that the effective charge scattered by an array of scatterers is
determined by the scattering strength of an individual scatterer and not by the
combined scattering strength of the array, which can be very small. Moreover,
we also rule out intra-edge equilibration of e/3 quasiparticles over length
scale of hundreds microns.Comment: 4 pages, 4 figure
Comparison of chemical profiles and effectiveness between Erxian decoction and mixtures of decoctions of its individual herbs : a novel approach for identification of the standard chemicals
Acknowledgements This study was partially supported by grants from the Seed Funding Programme for Basic Research (Project Number 201211159146 and 201411159213), the University of Hong Kong. We thank Mr Keith Wong and Ms Cindy Lee for their technical assistances.Peer reviewedPublisher PD
The Stochastic State Selection Method for Energy Eigenvalues in the Shastry-Sutherland Model
We apply a recently developed stochastic method to the Shastry-Sutherland
model on 4x4 and 8x8 lattices. This method, which we call the Stochastic State
Selection Method here, enables us to evaluate expectation values of powers of
the Hamiltonian with very limited number of states. In this paper we first
apply it to the 4x4 Shastry-Sutherland system, where one can easily obtain the
exact ground state, in order to demonstrate that the method works well for this
frustrated system. We numerically show that errors of the evaluations depend
much on representations of the states and that the restructured representation
is better than the normal one for this model. Then we study the 8x8 system to
estimate energy eigenvalues of the lowest S=1 state as well as of the lowest
excited S=0 state, where S denotes the total spin of the system. The results,
which are in good accordance with our previous data obtained by the Operator
Variational method, support that an intermediate spin-gap phase exists between
the singlet dimer phase and the magnetically ordered phase. Estimates of the
critical coupling and of the spin gap for the transition from the dimer phase
to the intermediate phase are also presented.Comment: 17 pages, 4 figure
KMT-2016-BLG-2052L: Microlensing Binary Composed of M Dwarfs Revealed from a Very Long Time-scale Event
We present the analysis of a binary microlensing event KMT-2016-BLG-2052, for
which the lensing-induced brightening of the source star lasted for 2 seasons.
We determine the lens mass from the combined measurements of the microlens
parallax \pie and angular Einstein radius \thetae. The measured mass
indicates that the lens is a binary composed of M dwarfs with masses of
and . The measured relative
lens-source proper motion of is smaller
than of typical Galactic lensing events, while
the estimated angular Einstein radius of \thetae\sim 1.2~{\rm mas} is
substantially greater than the typical value of .
Therefore, it turns out that the long time scale of the event is caused by the
combination of the slow and large \thetae rather than the heavy mass of
the lens. From the simulation of Galactic lensing events with very long time
scales ( days), we find that the probabilities that long
time-scale events are produced by lenses with masses and
are and 2.6\%, respectively, indicating that
events produced by heavy lenses comprise a minor fraction of long time-scale
events. The results indicate that it is essential to determine lens masses by
measuring both \pie and \thetae in order to firmly identify heavy stellar
remnants such as neutron stars and black holes.Comment: 9 pages, 11 figure
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