5,494 research outputs found
Recent results on beyond the standard model Higgs boson searches from CMS
Two extensions of the standard model, one that includes the seesaw mechanism
of type II, and the minimal supersymmetric extention to the standard model, are
studied using up to 1.6 fb^{-1} of data collected in proton-proton collisions
at sqrt{s}=7 TeV with the CMS detector at the LHC.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 3 pages, 5 figure
Prospects for Higgs and SM measurements at the HL-LHC
After a succesful startup of the LHC scientific program that has led to discovery of the Higgs boson it is time to make plans for the future. The high luminosity LHC (HLLHC) project is discussed, plans for possible Higgs and SM measurements are reviewed
Nonlinear Breathing-like Localized Modes in C60 Nanocrystals
We study the dynamics of nanocrystals composed of C60 fullerene molecules. We
demonstrate that such structures can support long-lived strongly localized
nonlinear oscillatory modes, which resemble discrete breathers in simple
lattices. We reveal that at room temperatures the lifetime of such nonlinear
localized modes may exceed tens of picoseconds; this suggests that C60
nanoclusters should demonstrate anomalously slow thermal relaxation when the
temperature gradient decays in accord to a power law, thus violating the
Cattaneo-Vernotte law of thermal conductivity.Comment: 6 pages, 6 figure
Non-stationary heat conduction in one-dimensional chains with conserved momentum
The Letter addresses the relationship between hyperbolic equations of heat
conduction and microscopic models of dielectrics. Effects of the non-stationary
heat conduction are investigated in two one-dimensional models with conserved
momentum: Fermi-Pasta-Ulam (FPU) chain and chain of rotators (CR). These models
belong to different universality classes with respect to stationary heat
conduction. Direct numeric simulations reveal in both models a crossover from
oscillatory decay of short-wave perturbations of the temperature field to
smooth diffusive decay of the long-wave perturbations. Such behavior is
inconsistent with parabolic Fourier equation of the heat conduction. The
crossover wavelength decreases with increase of average temperature in both
models. For the FPU model the lowest order hyperbolic Cattaneo-Vernotte
equation for the non-stationary heat conduction is not applicable, since no
unique relaxation time can be determined.Comment: 4 pages, 5 figure
Vibrational Tamm states at the edges of graphene nanoribbons
We study vibrational states localized at the edges of graphene nanoribbons.
Such surface oscillations can be considered as a phonon analog of Tamm states
well known in the electronic theory. We consider both armchair and zigzag
graphene stripes and demonstrate that surface modes correspond to phonons
localized at the edges of the graphene nanoribbon, and they can be classified
as in-plane and out-of-plane modes. In addition, in armchair nanoribbons
anharmonic edge modes can experience longitudinal localization in the form of
self-localized nonlinear modes, or surface breather solitons.Comment: 10 pages, 10 figure
Precision measurements of electroweak parameters at the LHC
A set of selected precise measurements of the SM parameters from the LHC experiments is discussed. Results on W-mass measurement and forwardbackward asymmetry in production of the Drell-Yan events in both dielectron and dimuon decay channels are presented together with results on the effective mixing angle measurements. Electroweak production of the vector bosons in association with two jets is discussed
Discrete breathers assist energy transfer to ac driven nonlinear chains
One-dimensional chain of pointwise particles harmonically coupled with
nearest neighbors and placed in six-order polynomial on-site potentials is
considered. Power of the energy source in the form of single ac driven
particles is calculated numerically for different amplitudes and
frequencies within the linear phonon band. The results for the on-site
potentials with hard and soft nonlinearity types are compared. For the
hard-type nonlinearity, it is shown that when the driving frequency is close to
(far from) the {\em upper} edge of the phonon band, the power of the energy
source normalized to increases (decreases) with increasing . In
contrast, for the soft-type nonlinearity, the normalized power of the energy
source increases (decreases) with increasing when the driving frequency is
close to (far from) the {\em lower} edge of the phonon band. Our further
demonstrations indicate that, in the case of hard (soft) anharmonicity, the
chain can support movable discrete breathers (DBs) with frequencies above
(below) the phonon band. It is the energy source quasi-periodically emitting
moving DBs in the regime with driving frequency close to the DBs frequency,
that induces the increase of the power. Therefore, our results here support the
mechanism that the moving DBs can assist energy transfer from the ac driven
particle to the chain.Comment: 11 pages, 13 figure
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