4,364 research outputs found
The First Year of the Large Hadron Collider: A Brief Review
The first year of LHC data taking provided an integrated luminosity of about
35/pb in proton-proton collisions at sqrt(s)=7 TeV. The accelerator and the
experiments have demonstrated an excellent performance. The experiments have
obtained important physics results in many areas, ranging from tests of the
Standard Model to searches for new particles. Among other results the physics
highlights have been the measurements of the W-, Z-boson and t t-bar production
cross-sections, improved limits on supersymmetric and other hypothetical
particles and the observation of jet-quenching, elliptical flow and J/Psi
suppression in lead-lead collisions at sqrt(sNN) = 2.76 TeV.Comment: 11 pages, 9 figures, invited brief review for Mod. Phys. Lett.
Exploring singlet deflection of gauge mediation
We embed the Next-to Minimal Supersymmetric Standard Model into gauge
mediation of supersymmetry breaking and study the phenomenology of scenarios
where the gauge-mediation contributions to soft parameters are deflected by
superpotential interactions of the gauge singlet with the messenger fields and
the Higgs doublets. This kind of models provide a satisfactory solution to the
mu-b_mu problem of gauge mediation, compatible with the adequate pattern of
electroweak symmetry breaking and a realistic spectrum with supersymmetric
partners at the TeV scale without requiring a significant fine tuning.Comment: Latex 18 pages, 4 eps figures. Minor corrections, version published
in Phys. Rev.
The estimation of neutrino fluxes produced by proton-proton collisions at TeV of the LHC
Intense and collimated neutrino beams are produced by charm and beauty
particle decays from proton-proton collisions at the LHC. A neutrino experiment
would be run parasitically without interrupting the LHC physics program during
the collider run. We estimate the neutrino fluxes from proton-proton collisions
at TeV of the LHC with the designed luminosity, 10^{34} \lumi.
By mounting about 200 tons of fiducial volume of a neutrino detector at 300
\m away from the interaction point, about 150,000 of charged current neutrino
events per year can be observable.Comment: 8 pages, Accepted in JHE
Forward-Backward Correlations and Event Shapes as probes of Minimum-Bias Event Properties
Measurements of inclusive observables, such as particle multiplicities and
momentum spectra, have already delivered important information on
soft-inclusive ("minimum-bias") physics at the Large Hadron Collider. In order
to gain a more complete understanding, however, it is necessary to include also
observables that probe the structure of the studied events. We argue that
forward-backward (FB) correlations and event-shape observables may be
particulary useful first steps in this respect. We study the sensitivity of
several different types of FB correlations and two event shape variables -
transverse thrust and transverse thrust minor - to various sources of
theoretical uncertainty: multiple parton interactions, parton showers, colour
(re)connections, and hadronization. The power of each observable to furnish
constraints on Monte Carlo models is illustrated by including comparisons
between several recent, and qualitatively different, PYTHIA 6 tunes, for pp
collisions at sqrt(s) = 900 GeV.Comment: 13 page
Excitation of nonlinear two-dimensional wake waves in radially-nonuniform plasma
It is shown that an undesirable curvature of the wave front of
two-dimensional nonlinear wake wave excited in uniform plasma by a relativistic
charged bunch or laser pulse may be compensated by radial change of the
equilibrium plasma density.Comment: 6 pages, 4 figure
On the Earth's tidal perturbations for the LARES satellite
Frame dragging, one of the outstanding phenomena predicted by General
Relativity, is efficiently studied by means of the laser-ranged satellites
LARES, LAGEOS and LAGEOS 2. The accurate analysis of the orbital perturbations
of Earth's solid and ocean tides has been relevant for increasing the accuracy
in the test of frame-dragging using these three satellites. The Earth's tidal
perturbations acting on the LARES satellite are obtained for the 110
significant modes of corresponding Doodson number and are exhibited to enable
the comparison to those of the LAGEOS and LAGEOS-2 satellites. For LARES we
represent 29 perturbation modes for l=2,3,4 for ocean tides.Comment: 14 pages, 9 figures, to appear in Eur Phys J Plus (subm. Sept 20,
2017
To the center of cold spot with Planck
The structure of the cold spot, of a non-Gaussian anomaly in the cosmic
microwave background (CMB) sky first detected by Vielva et al. is studied using
the data by Planck satellite. The obtained map of the degree of stochasticity
(K-map) of CMB for the cold spot, reveals, most clearly in 100 GHz band, a
shell-type structure with a center coinciding with the minima of the
temperature distribution. The shell structure is non-Gaussian at a 4\sigma
confidence level. Such behavior of the K-map supports the void nature of the
cold spot. The applied method can be used for tracing voids that have no
signatures in redshift surveys.Comment: A & A (in press), 4 pages, 5 figures; to match the published versio
- …