5,914 research outputs found
Direct solution of the hard pomeron problem for arbitrary conformal weight
A new method is applied to solve the Baxter equation for the one dimensional
system of noncompact spins. Dynamics of such an ensemble is equivalent to that
of a set of reggeized gluons exchanged in the high energy limit of QCD
amplitudes. The technique offers more insight into the old calculation of the
intercept of hard Pomeron, and provides new results in the odderon channel.Comment: Contribution to the ICHEP96 Conference, July 1996, Warsaw, Poland.
LaTeX, 4 pages, 3 epsf figures, includes modified stwol.sty file. Some
references were revise
Solution of the Odderon Problem
The intercept of the odderon trajectory is derived, by finding the spectrum
of the second integral of motion of the three reggeon system in high energy
QCD. When combined with earlier solution of the appropriate Baxter equation,
this leads to the determination of the low lying states of that system. In
particular, the energy of the lowest state gives the intercept of the odderon
alpha_O(0)=1-0.2472 alpha_s N_c/pi.Comment: 11 pages, 2 Postscript figure
Reggeon exchange from AdS/CFT
Using the AdS/CFT correspondence in a confining backgroundand the worldline
formalism of gauge field theories,we compute scattering amplitudes with an
exchange of quark andantiquark in the -channel corresponding to Reggeon
exchange. Itrequires going beyond the eikonal approximation, which was used
when studying Pomeron exchange. The wordline path integral is evaluated through
the determination of minimal surfaces and their boundaries by the saddle-point
method at large gauge coupling g^2N_c. We find a Regge behaviour with linear
Regge trajectories. The slope is related to the static potential and
is four times the Pomeronslope obtained in the same framework. A contribution
to the intercept, related to the L\"uscher term, comes from the fluctuations
around the minimal surface.Comment: 11 pages, 1 eps figur
Effective Low Energy Theories and QCD Dirac Spectra
We analyze the smallest Dirac eigenvalues by formulating an effective theory
for the QCD Dirac spectrum. We find that in a domain where the kinetic term of
the effective theory can be ignored, the Dirac eigenvalues are distributed
according to a Random Matrix Theory with the global symmetries of the QCD
partition function. The kinetic term provides information on the slope of the
average spectral density of the Dirac operator. In the second half of this
lecture we interpret quenched QCD Dirac spectra at nonzero chemical potential
(with eigenvalues scattered in the complex plane) in terms of an effective low
energy theory.Comment: Invited talk at the 10th International Conference on Recent Progress
in Many-Body Theories (MBX), Seattle, September 1999, 13 pages, Latex, with 1
figure, uses ws-p9-75x6-50.cl
A study of the influence of Hg(6(3)P2) population in a low-pressure discharge on mercury ion emission at 194.2 nm
A low-pressure mercury-argon discharge, similar to the type existing in the mercury lamp for the trapped-ion standard, is probed with a new technique of laser spectroscopy to determine the influence of the Hg(6 3P(sub 2)) population on discharge emission. The discharge is excited with inductively coupled rf power. Variations in the intensity of emission lines in the discharge were examined as lambda = 546.1 nm light from a continuous wave (CW) laser excited the Hg(6 3P(sub 2)) to (7 3S (sub 1)) transition. The spectrum of the discharge viewed in the region of laser irradiation showed increased emission in lambda = 546.1, 435.8, 404.7, 253.7, and 194.2 nm lines. Other lines in Hg I exhibited a decrease in emission. When the discharge was viewed outside the region of laser irradiation, all lines exhibited an increased emission. Based on these results, it is concluded that the dominant mechanism for the excitation of higher lying levels of mercury is the the electron-impact excitation via the 3P(sub 2) level. The depopulation of this metastable is also responsible for the observed increase in the electron temperature when the laser irradiates the discharge. It is also concluded that the 3P(sub 2) metastable level of mercury does not play a significant role in the excitation of the 3P(sub 1/2) level of mercury ion
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