223,383 research outputs found
Measurement of Event Plane Correlations in Pb-Pb Collisions at =2.76 TeV with the ATLAS Detector
A measurement of correlations between event-plane angles is
presented as a function of centrality for Pb-Pb collisions at
TeV. These correlations are estimated from
observed event-plane angles obtained from charged particle or
transverse energy flow measured over a large pseudorapidity range ,
followed by a resolution correction that accounts for the dispersion of
relative to . Various correlators involving two or three event
planes with acceptable resolution are measured. Significant positive
correlations are observed for , ,
, , and
. However, the measured correlations for
are negative. These results may shed light on the
patterns of the fluctuation of the created matter in the initial state as well
as the subsequent hydrodynamic evolution.Comment: 5 pages, 4 figures. Proceedings for Hard Probes 2012, Cagliari, Ital
Digging for biosynthetic dark matter.
An analysis of bacterial communities in soil samples from around the world reveals unexplored diversity in biosynthetic enzymes
Inclusive production at factories
Within the nonrelativistic QCD (NRQCD) factorization framework, we
investigate the inclusive production of the meson associated with either
light hadrons or charmed hadrons at factory energy GeV.
Both the leading color-singlet and color-octet channels are included. For the
production associated with light hadrons, the total production rate is
dominated by the color-octet channel, thus the future measurement of this
process may impose useful constraint on the value of the color-octet matrix
element ; for the production associated with
charmed hadrons, the total production rate is about one order of magnitude
smaller, and dominated by the color-singlet channel.Comment: v2, 23 pages, 1 table, 6 figures. Minor corrections, and a note
added, accepted for publication in PR
Exclusive decay of into
We study the exclusive decay into double charmonium, specifically,
the -wave charmonium plus the -wave charmonium
in the NRQCD factorization framework. Three distinct decay mechanisms, i.e.,
the strong, electromagnetic and radiative decay channels are included and their
interference effects are investigated. The decay processes
are predicted to have the branching
fractions of order , which should be observed in the prospective Super
factory.Comment: 22 pages, 9 figures, 3 table
Distributed control design for underwater vehicles
The vast majority of control applications are based on non-interacting decentralized control designs. Because of their single-loop structure, these controllers cannot suppress interactions of the system. It would be useful to tackle the undesirable effects of the interactions at the design stage. A novel model predictive control scheme based on Nash optimality is presented to achieve this goal. In this algorithm, the control problem is decomposed into that of several small-coupled mixed integer optimisation problems. The relevant computational convergence, closed-loop performance and the effect of communication failures on the closed-loop behaviour are analysed. Simulation results are presented to illustrate the effectiveness and practicality of the proposed control algorithm
Surjective endomorphisms of projective surfaces -- the existence of infinitely many dense orbits
Let be a surjective endomorphism of a normal projective
surface. When , applying an (iteration of)
-equivariant minimal model program (EMMP), we determine the geometric
structure of . Using this, we extend the second author's result to singular
surfaces to the extent that either has an -invariant non-constant
rational function, or has infinitely many Zariski-dense forward orbits;
this result is also extended to Adelic topology (which is finer than Zariski
topology)
Which hadronic decay modes are good for searching: double or something else?
It has been controversial whether can be discovered in Tevatron Run
2 through the decay followed by . We clear this controversy by an explicit calculation which
predicts to be of order . It is
concluded that observing eta_b through this decay mode in Tevatron Run 2 is
rather unrealistic. The eta_b may be observed in the forthcoming LHC
experiments through the 4-lepton channel, if the background events can be
significantly reduced by imposing some kinematical cuts. By some rough but
plausible considerations, we find that the analogous decay processes eta_b to
VV, D^*\bar{D}^* also have very suppressed branching ratios, nevertheless it
may be worth looking for \eta_b at LHC and Super B factory through the decay
modes \eta_b \to K_S K^{\pm}\pi^{\mp}, D^*\bar{D}.Comment: v2; 28 pages, 2 figures. References added, presentation improved.
Discussion on possible nonperturbative mechanism for eta_b->VV added,
analysis for eta_b->VP updated by incoprating the U-spin violation effec
Quantifying the impact of future Sandage-Loeb test data on dark energy constraints
The Sandage-Loeb (SL) test is a unique method to probe dark energy in the
"redshift desert" of , and thus it provides an important
supplement to the other dark energy probes. Therefore, it is of great
importance to quantify how the future SL test data impact on the dark energy
constraints. To avoid the potential inconsistency in data, we use the
best-fitting model based on the other geometric measurements as the fiducial
model to produce 30 mock SL test data. The 10-yr, 20-yr, and 30-yr observations
of SL test are analyzed and compared in detail. We show that compared to the
current combined data of type Ia supernovae, baryon acoustic oscillation,
cosmic microwave background, and Hubble constant, the 30-yr observation of SL
test could improve the constraint on by about and the
constraint on by about . Furthermore, the SL test can also improve the
measurement of the possible direct interaction between dark energy and dark
matter. We show that the SL test 30-yr data could improve the constraint on
by about and for the and models, respectively.Comment: 10 pages, 3 figure
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