1,103 research outputs found
Spin-dependent energy distribution of B-hadrons from polarized top decays considering the azimuthal correlation rate
In our previous work, we studied the polar distribution of the scaled energy
of bottom-flavored hadrons from polarized top quark decays
, using two different helicity
coordinate systems. Basically, the energy distributions are governed by the
unpolarized, polar and azimuthal rate functions which are related to the
density matrix elements of the decay . Here we
present, for the first time, the analytical expressions for the radiative corrections to the differential azimuthal decay rates
of the partonic process in two helicity
systems, which are needed to study the azimuthal distribution of the energy
spectrum of the B-hadron produced in polarized top quark decays. Our
predictions of the hadron energy distributions enable us to deepen our
knowledge of the hadronization process and to determine the polarization states
of top quarks
Motion of nanodroplets near chemical heterogeneities
We investigate the dynamics of nanoscale droplets in the vicinity of chemical
steps which separate parts of a substrate with different wettabilities. Due to
long-ranged dispersion forces, nanodroplets positioned on one side of the step
perceive the different character of the other side even at some distances from
the step, leading to a dynamic response. The direction of the ensuing motion of
such droplets does not only depend on the difference between the equilibrium
contact angles on these two parts but in particular on the difference between
the corresponding Hamaker constants. Therefore the motion is not necessarily
directed towards the more wettable side and can also be different from that of
droplets which span the step.Comment: 6 pages, 6 figure
Heavy quark fragmentation functions at next-to-leading perturbative QCD
It is well-known that the dominant mechanism to produce hadronic bound states
with large transverse momentum is fragmentation. This mechanism is described by
the fragmentation functions (FFs) which are the universal and
process-independent functions. Here, we review the perturbative FFs formalism
as an appropriate tool for studying these hadronization processes and detail
the extension of this formalism at next-to-leading order (NLO). Using the
Suzuki's model, we calculate the perturbative QCD FF for a heavy quark to
fragment into a S-wave heavy meson at NLO. As an example, we study the LO and
NLO FFs for a charm quark to split into the S-wave -meson and compare our
analytic results both with experimental data and well-known phenomenological
models
Stripe formation in horizontally oscillating granular suspensions
We present the results of an experimental study of pattern formation in
horizontally oscillating granular suspensions. Starting from a homogeneous
state, the suspension turns into a striped pattern within a specific range of
frequencies and amplitudes of oscillation. We observe an initial development of
layered structures perpendicular to the vibration direction and a gradual
coarsening of the stripes. However, both processes gradually slow down and
eventually saturate. The probability distribution of the stripe width
approaches a nonmonotonic steady-state form which can be approximated by a
Poisson distribution. We observe similar structures in MD simulations of soft
spherical particles coupled to the motion of the surrounding fluid.Comment: 7 pages, 8 figures, to appear in Europhys. Lett. (2014
Motion of nanodroplets near edges and wedges
Nanodroplets residing near wedges or edges of solid substrates exhibit a
disjoining pressure induced dynamics. Our nanoscale hydrodynamic calculations
reveal that non-volatile droplets are attracted or repelled from edges or
wedges depending on details of the corresponding laterally varying disjoining
pressure generated, e.g., by a possible surface coating.Comment: 12 pages, 7 figure
Chemical and sensory properties of fish sauce using dried rainbow sardine (Dussumieria acuta)
Fish sauce is a dark liquid which produced from fish fermentation in a very high salt condition. This product has a long history and is produced in different procedures and names throughout the world. In Iran, production of fish sauce consists of two steps. At first, fermented extract or Suru is produced from fresh or dried sardine, and Suru is cured with the addition of spices. This study was conducted for the first time in Iran for industrial production of fish sauce from dried Sardine. For this study, fresh sardine was provided from Bandar Abbas Fishery Center. The fish were sun-dried and used for fish sauce production. The effects of mechanical dicing, adding of salt in two levels (100 and 80 percent) and addition of citric acid at 2% were investigated. Sampling was achieved with separation of aqueous phase by vacuum and filter paper. Then, acidity, electrical conductivity, total nitrogen, trimethylamine and salt concentration were measured in the extracted liquid. Results showed that acidity, electrical conductivity and total nitrogen increased, however, the salt content remained constant and the trimethylamine content was decreased during fermentation period. Increase in total nitrogen indicated an increase in protein hydrolysis and nutritional value of the product. Whereas, reduction in trimethylamine content showed a decrease in the number of spoilage bacteria during fermentation. The highest score in sensory evaluation of the products belonged to the low salt (80%) treatment
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