147,117 research outputs found
A complete O(alpha_S^2) calculation of the signal-background interference for the Higgs diphoton decay channel
We present the full {\cal O}(\as^2) computation of the interference effects
between the Higgs diphoton signal and the continuum background at the LHC.
While the main contribution to the interference originates on the partonic
subprocess, we find that the corrections from the and channels
amount up to 35% of it. We discuss the effect of these new subprocesses in the
shift of the diphoton invariant mass peak recently reported by S. Martin in
Ref.\cite{Martin:2012xc}.Comment: 8 pages, 5 figure
On the computation of finite bottom-quark mass effects in Higgs boson production
We present analytic results for the partonic cross-sections contributing to
the top-bottom interference in Higgs production via gluon fusion at hadron
colliders at NLO accuracy in QCD. We develop a method of expansion in small
bottom-mass for master integrals and combine it with the usual infinite
top-mass effective theory. Our method of expansion admits a simple algorithmic
description and can be easily generalized to any small parameter. These results
for the integrated cross-sections will be needed in the computation of the
renormalization counter-terms entering the computation of finite bottom-quark
mass effects at NNLO.Comment: Updated affiliations and abstract, added reference, and corrected
minor typo
Efficient high-fidelity quantum computation using matter qubits and linear optics
We propose a practical, scalable, and efficient scheme for quantum
computation using spatially separated matter qubits and single photon
interference effects. The qubit systems can be NV-centers in diamond,
Pauli-blockade quantum dots with an excess electron or trapped ions with
optical transitions, which are each placed in a cavity and subsequently
entangled using a double-heralded single-photon detection scheme. The fidelity
of the resulting entanglement is extremely robust against the most important
errors such as detector loss, spontaneous emission, and mismatch of cavity
parameters. We demonstrate how this entangling operation can be used to
efficiently generate cluster states of many qubits, which, together with single
qubit operations and readout, can be used to implement universal quantum
computation. Existing experimental parameters indicate that high fidelity
clusters can be generated with a moderate constant overhead.Comment: 5 pages, 3 figures, broader introduction and improved scalability of
cluster state generatio
Quantum Computation as a Dynamical Process
In this paper, we discuss the dynamical issues of quantum computation. We
demonstrate that fast wave function oscillations can affect the performance of
Shor's quantum algorithm by destroying required quantum interference. We also
show that this destructive effect can be routinely avoided by using
resonant-pulse techniques. We discuss the dynamics of resonant pulse
implementations of quantum logic gates in Ising spin systems. We also discuss
the influence of non-resonant excitations. We calculate the range of parameters
where undesirable non-resonant effects can be minimized. Finally, we describe
the ``-method'' which avoids the detrimental deflection of non-resonant
qubits.Comment: 13 pages, 1 column, no figure
Vector boson production at hadron colliders: a fully exclusive QCD calculation at NNLO
We consider QCD radiative corrections to the production of W and Z bosons in
hadron collisions. We present a fully exclusive calculation up to
next-to-next-to-leading order (NNLO) in QCD perturbation theory. To perform
this NNLO computation, we use a recently proposed version of the subtraction
formalism. The calculation includes the gamma-Z interference, finite-width
effects, the leptonic decay of the vector bosons and the corresponding spin
correlations. Our calculation is implemented in a parton level Monte Carlo
program. The program allows the user to apply arbitrary kinematical cuts on the
final-state leptons and the associated jet activity, and to compute the
corresponding distributions in the form of bin histograms. We show selected
numerical results at the Tevatron and the LHC.Comment: 7 pages, 3 ps figure
Higgs production in association with bottom quarks
We study the production of a Higgs boson in association with bottom quarks in
hadronic collisions, and present phenomenological predictions relevant to the
13 TeV LHC. Our results are accurate to the next-to-leading order in QCD, and
matched to parton showers through the MC@NLO method; thus, they are fully
differential and based on unweighted events, which we shower by using both
Herwig++ and Pythia8. We perform the computation in both the four-flavour and
the five-flavour schemes, whose results we compare extensively at the level of
exclusive observables. In the case of the Higgs transverse momentum, we also
consider the analytically-resummed cross section up to the NNLO+NNLL accuracy.
In addition, we analyse at the effects of the
interference between the and gluon-fusion production modes.Comment: 33 pages, 17 figure
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