563 research outputs found
Directed Percolation Universality in Asynchronous Evolution of Spatio-Temporal Intermittency
We present strong evidence that a coupled-map-lattice model for
spatio-temporal intermittency belongs to the universality class of directed
percolation when the updating rules are asynchronous, i.e. when only one
randomly chosen site is evolved at each time step. In contrast, when the system
is subjected to parallel updating, available numerical evidence suggests that
it does not belong to this universality class and that it is not even
universal. We argue that in the absence of periodic external forcing, the
asynchronous rule is the more physical.Comment: 12 pages, RevTeX, includes 6 figures, submitted to Physical Review
Letters; changed version includes a better physical motivation for
asynchronous updates, extra references and minor change
Physical Characteristics of the Spectral States of Galactic Black Holes
Using simple analytical estimates we show how the physical parameters
characterizing different spectral states of the galactic black hole candidates
can be determined using spectral data presently available.Comment: 5 pages, 3 figures, to appear in the Proceedings of 4th Compton
Symposium, April 27-30, 1997, Williamsburg, Virginia, US
Functional Derivative of the Zero Point Energy Functional from the Strong Interaction Limit of Density Functional Theory
We derive an explicit expression for the functional derivative of the
subleading term in the strong interaction limit expansion of the generalized
Levy--Lieb functional for the special case of two electrons in one dimension.
The expression is derived from the zero point energy (ZPE) functional, which is
valid if the quantum state reduces to strongly correlated electrons in the
strong coupling limit. The explicit expression is confirmed numerically and
respects the relevant sum-rule. We also show that the ZPE potential is able to
generate a bond mid-point peak for homo-nuclear dissociation and is properly of
purely kinetic origin. Unfortunately, the ZPE diverges for Coulomb systems,
whereas the exact peaks should be finite.Comment: 12 pages, 7 figure
Photon-induced contributions to di-lepton production at the LHC Run II
We report on recent studies of photon-induced (PI) contributions to di-lepton
production and their implications for Beyond Standard Model (BSM)
-bosons searches at the LHC.Comment: Proceedings of XXV International Workshop on Deep-Inelastic
Scattering and Related Subjects, 3-7 April 2017, University of Birmingham, U
Real and virtual photons effects in di-lepton production at the LHC
We show the SM prediction of di-lepton production at the LHC where to the
usual Drell-Yan production we add the contribution from Photon-Initiated
processes. We discuss the effects of the inclusion of photon interactions in
the high invariant mass region (TeV region) and their consequences on BSM heavy
Z'-boson searches.Comment: 7 pages, 6 figures, Proceeding of Les Rencontres de Physique de la
Vall\'ee d'Aoste, La Thuile 201
The effect of real and virtual photons in the di-lepton channel at the LHC
We present a study of di-lepton production at the CERN Large Hadron Collider
with a particular focus on the contribution resulting from both real and
virtual photons in the initial state. We discuss the region of phase space in
which the invariant mass of the lepton pair is of the order of several TeV,
where searches for new physics phenomena yielding a di-lepton signature are
presently carried out. We study both the yield and associated uncertainties for
all possible topologies in photon-induced di-lepton production and compare
these with what is expected in the standard Drell-Yan channel, where
quark-antiquark pairs are responsible for the production of lepton pairs. We
analyse the impact of these QED contributions on the expected Standard Model
background and on searches for new physics. In this latter case, we use the
production of an extra heavy -boson predicted by the Sequential
Standard Model (SSM) as a benchmark process.Comment: 9 pages, 5 figure
Drell-Yan production of multi Z'-bosons at the LHC within Non-Universal ED and 4D Composite Higgs Models
The Drell-Yan di-lepton production at hadron colliders is by far the
preferred channel to search for new heavy spin-1 particles. Traditionally, such
searches have exploited the Narrow Width Approximation (NWA) for the signal,
thereby neglecting the effect of the interference between the additional
Z'-bosons and the Standard Model Z and {\gamma}. Recently, it has been
established that both finite width and interference effects can be dealt with
in experimental searches while still retaining the model independent approach
ensured by the NWA. This assessment has been made for the case of popular
single Z'-boson models currently probed at the CERN Large Hadron Collider
(LHC). In this paper, we test the scope of the CERN machine in relation to the
above issues for some benchmark multi Z'-boson models. In particular, we
consider Non-Universal Extra Dimensional (NUED) scenarios and the 4-Dimensional
Composite Higgs Model (4DCHM), both predicting a multi-Z' peaking structure. We
conclude that in a variety of cases, specifically those in which the leptonic
decays modes of one or more of the heavy neutral gauge bosons are suppressed
and/or significant interference effects exist between these or with the
background, especially present when their decay widths are significant,
traditional search approaches based on the assumption of rather narrow and
isolated objects might require suitable modifications to extract the underlying
dynamics
Peptide Retention in Hydrophilic Strong Anion Exchange Chromatography Is Driven by Charged and Aromatic Residues
Hydrophilic
strong anion exchange chromatography (hSAX) is becoming
a popular method for the prefractionation of proteomic samples. However,
the use and further development of this approach is affected by the
limited understanding of its retention mechanism and the absence of
elution time prediction. Using a set of 59 297 confidentially
identified peptides, we performed an explorative analysis and built
a predictive deep learning model. As expected, charged residues are
the major contributors to the retention time through electrostatic
interactions. Aspartic acid and glutamic acid have a strong retaining
effect and lysine and arginine have a strong repulsion effect. In
addition, we also find the involvement of aromatic amino acids. This
suggests a substantial contribution of cation−π interactions
to the retention mechanism. The deep learning approach was validated
using 5-fold cross-validation (CV) yielding a mean prediction accuracy
of 70% during CV and 68% on a hold-out validation set. The results
of this study emphasize that not only electrostatic interactions but
rather diverse types of interactions must be integrated to build a
reliable hSAX retention time predictor
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