28,170 research outputs found
From the exclusive photoproduction of heavy quarkonia at HERA to the EDDE at TeVatron and LHC
Exclusive photoproduction of heavy quarkonia at HERA is analyzed in the
framework of the Regge-eikonal approach together with the nonrelativistic bound
state formalism. Total and differential cross-sections for the process
are calculated. The model predicts
cross-sections of Exclusive Double Diffractive Events (EDDE) at TeVatron and
LHC.Comment: 14 pages, 6 figures, reference is adde
The KCAL VERA 22 GHz calibrator survey
We observed at 22 GHz with the VLBI array VERA a sample of 1536 sources with
correlated flux densities brighter than 200 mJy at 8 GHz. One half of target
sources has been detected. The detection limit was around 200 mJy. We derived
the correlated flux densities of 877 detected sources in three ranges of
projected baseline lengths. The objective of these observations was to
determine the suitability of given sources as phase calibrators for dual-beam
and phase-referencing observations at high frequencies. Preliminary results
indicate that the number of compact extragalactic sources at 22 GHz brighter
than a given correlated flux density level is twice less than at 8 GHz.Comment: Accepted for publication by the Astronomical Journal. 6 pages, 3
figures, 3 table. The machine readable catalogue file, kcal_cat.txt can be
extracted from the source of this submissio
Charm mixing in the Standard Model and beyond
The motivation most often cited in searches for D0-anti-D0 mixing and
CP-violation in charm system lies with the possibility of observing a signal
from New Physics which dominates that from the Standard Model. We review recent
theoretical predictions and experimental constraints on D0-anti-D0 mixing
parameters, concentrating on possible effects of New Physics.Comment: 8 pages, 2 figures, Invited talk at International Workshop on
Tau-Charm Physics (Charm 2006), Beijing, China, 5-7 Jun 200
Parametric Excitation of a 1D Gas in Integrable and Nonintegrable Cases
We study the response of a highly excited 1D gas with pointlike interactions
to a periodic modulation of the coupling constant. We calculate the
corresponding dynamic structure factors and show that their low-frequency
behavior differs dramatically for integrable and nonintegrable models.
Nonintegrable systems are sensitive to excitations with frequencies as low as
the mean level spacing, whereas much higher frequencies are required to excite
an integrable system. This effect can be used as a probe of integrability for
mesoscopic 1D systems and can be observed experimentally by measuring the
heating rate of a parametrically excited gas.Comment: Published version, 4 pages, 2 figure
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