3,999 research outputs found
Upsilon Dissociation in Quark-Gluon Plasma
I consider the dissociation of the upsilon meson due to absorption of a
thermal gluon. I discuss the dissociation rate in terms of the energy density,
the number density, and the temperature of the quark-gluon plasma. I compare
this to the effect due to screening.Comment: 5 pages, added calculations on screening; added figur
Clear Experimental Signature of Charge-Orbital density wave in NdCaMnO
Single Crystals of NdCaMnO have been prepared by the
travelling floating-zone method, and possible evidence of a charge -orbital
density wave in this material presented earlier [PRB68,092405 (2003)] using
High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In
the current note we present direct evidence of charge-orbital ordering in this
material using heat capacity measurements. Our heat capacity measurements
indicate a clear transition consistent with prior observation. We find two main
transitions, one at temperature K, and other at
K. In addition, we may also conclude that there is a strong electron-phonon
coupling in this material.Comment: 7 pages, 8 figure
Charmonium at finite temperature
We study charmoinum correlators and spectral functions at finite temperature
within the quenched approximation using isotropic lattices with lattice spacing
a^-1=4.86 GeV and 9.72 GeV. Although we observe some medium modifications of
the ground state charmonium spectral function above deconfinement, we find that
ground state charmonia (J/psi and eta_c) exist in the deconfined phase at least
up to temperatures as high as 1.5Tc. P-wave charmonia (chi_c) on the other hand
are dissociated already at 1.12Tc.Comment: Contribution to Lattice 2003 (non-zero) LaTeX, 3 pages, 3 figures,
uses espcrc2 styl
Diagnosis of infections in newborns using a new particle-mediated immunoassay for serum C-reactive protein
C-reactive protein (CRP) levels were measured using a new particle-mediated immunoassay. Tests for precision and linearity of this method gave satisfactory results. The minimum sensitivity of the assay was 1 ng/ml. Interference by bilirubin (<220mg/l) and haemoglobin (<20g/l) was not observed. Using this method,
CRP was assayed as a means of monitoring for infection in newborns up to 72 h after delivery. The pattern of time course elevation curves was similar for both groups (10 healthy subjects and 26 patients), but the serum CRP (ng/ml) of infected newborns rose significantly higher than in healthy subjects at 24 h after birth. The rate of increase of CRP (∆CRP; ng/ml/h) may be a more useful parameter to detect infection, since a significant change in ∆CRP was apparent only 12 h after birth. The reported method was reliable and the parameters obtained were considered clinically useful for early detection of infection
Lidar observation of ozone over Tsukuba (36 deg N, 140 deg E)
An ozone lidar system was installed at the National Institute for Environmental Studies (NIES) in Tsukuba, Japan in March 1988 and has been measuring vertical profiles of ozone (15 - 45 km) since September 1988. The lidar system consists of a XeCl (308 nm) excimer laser, its deuterium Raman shifter (339 nm), a XeF excimer laser (351 nm), a 2 m telescope, a receiving system and a data processing system. The precision of the derived ozone concentration is about 10 percent of an altitude of 40 km for a 4 hr observation. Temperature profiles (30 - 80 km) are also obtained from the Rayleigh scattering signals at 351 nm. Approximate 50 ozone measurements are carried out in a year and variations of vertical profiles of ozone such as seasonal variations and shorter-term variations are observed. Systematic errors due to aerosols had been negligible until the arrival of the stratospheric aerosols injected by the eruption of Mt. Pinatubo. Effects of the volcanic aerosols on ozone measurements depend on the differences between wavelengths used as the on- and off-resonance
Diquark and triquark correlations in the deconfined phase of QCD
We use the non-perturbative Q\bar Q potential at finite temperatures derived
in the Field Correlator Method to obtain binding energies for the lowest
eigenstates in the Q\bar Q and QQQ systems (Q=c,b). The three--quark problem is
solved by the hyperspherical method. The solution provides an estimate of the
melting temperature and the radii for the different diquark and triquark bound
states. In particular we find that J/\psi and ground states survive up to
T \sim 1.3 T_c, where T_c is the critical temperature, while the corresponding
bottomonium states survive even up to higher temperature, T \sim 2.2 T_c.Comment: 11 pages, 1 figure; published versio
Dileptons from a Quark Gluon Plasma with Finite Baryon Density
We investigate the effects of a baryon-antibaryon asymmetry on the spectrum
of dileptons radiating from a quark gluon plasma. We demonstrate the existence
of a new set of processes in this regime. The dilepton production rate from the
corresponding diagrams is shown to be as important as that obtained from the
usual quark-antiquark annihilation.Comment: 20 pages, 5 figures, REVTEX. Typos corrected, references added.
Version accepted for publication in Physical Review
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