1,588 research outputs found
Mass Corrections to the Vector Current Correlator
Three-loop QCD corrections to the vector current correlator are considered.
The large momentum procedure is applied in order to evaluate mass corrections
up to order . The inclusion of the first seven terms to the ratio
leads to reliable
predictions from the high energy region down to relatively close to threshold.Comment: 16 pages, LaTeX, 11 postscript figures. The complete paper, including
figures, is also available via anonymous ftp at
ftp://ttpux2.physik.uni-karlsruhe.de/ , or via www at
http://www-ttp.physik.uni-karlsruhe.de/cgi-bin/preprints
Dynamics of the Tippe Top via Routhian Reduction
We consider a tippe top modeled as an eccentric sphere, spinning on a
horizontal table and subject to a sliding friction. Ignoring translational
effects, we show that the system is reducible using a Routhian reduction
technique. The reduced system is a two dimensional system of second order
differential equations, that allows an elegant and compact way to retrieve the
classification of tippe tops in six groups as proposed in [1] according to the
existence and stability type of the steady states.Comment: 16 pages, 7 figures, added reference. Typos corrected and a forgotten
term in de linearized system is adde
Recommended from our members
Land resource assessment of Northern Belize (NRI Bulletin 43, Volume 1 of 2)
The land resource assessment was undertaken from July 1989 to June 1990 by the Natural Resources Institute (NRI) of the Overseas Development Administration (ODA), assisted by Mr. A. C. S. Wright, and Dr. M. Holder of Central Farm. The main object of the survey was to produce an updated land suitability assessment of Orange Walk, Corozal, Belize and Cayo districts which had not already been surveyed by Jenkin et al. (1976) and King et al. (1989). In addition, this survey would provide a land suitability assessment for the Belize Valley based on the soil mapping of )en kin et al. Thus, together with the land resource assessments of Toledo and Stann Creek districts (King et al., 1986, 1989 respectively), a land suitability assessment for the whole of Belize is now available
Recommended from our members
Land resource assessment of Northern Belize (NRI Bulletin 43, Volume 2 of 2)
The land resource assessment was undertaken from July 1989 to June 1990 by the Natural Resources Institute (NRI) of the Overseas Development Administration (ODA), assisted by Mr. A. C. S. Wright, and Dr. M. Holder of Central Farm. The main object of the survey was to produce an updated land suitability assessment of Orange Walk, Corozal, Belize and Cayo districts which had not already been surveyed by Jenkin et al. (1976) and King et al. (1989). In addition, this survey would provide a land suitability assessment for the Belize Valley based on the soil mapping of )en kin et al. Thus, together with the land resource assessments of Toledo and Stann Creek districts (King et al., 1986, 1989 respectively), a land suitability assessment for the whole of Belize is now available
Relation between the pole and the minimally subtracted mass in dimensional regularization and dimensional reduction to three-loop order
We compute the relation between the pole quark mass and the minimally
subtracted quark mass in the framework of QCD applying dimensional reduction as
a regularization scheme. Special emphasis is put on the evanescent couplings
and the renormalization of the epsilon-scalar mass. As a by-product we obtain
the three-loop on-shell renormalization constants Zm(OS) and Z2(OS) in
dimensional regularization and thus provide the first independent check of the
analytical results computed several years ago.Comment: 22 page
RunDec: a Mathematica package for running and decoupling of the strong coupling and quark masses
In this paper the formulae are collected which are needed for the computation
of the strong coupling constant and quark masses at different energy scales and
for different number of active flavours. All equations contain the
state-of-the-art QCD corrections up to three- and sometimes even four-loop
order. For the practical implementation {\tt Mathematica} is used and a package
containing useful procedures is provided.Comment: 32 pages, ps figures included, accepted for publication in Computer
Physics Communication
Three-Loop Chromomagnetic Interaction in HQET
We compute the three-loop QCD corrections to the quark chromomagnetic moment
and thus obtain the matching coefficient and the anomalous dimension of the
chromomagnetic interaction in HQET. As a byproduct we obtain the three-loop
corrections to the quark anomalous magnetic moment.Comment: 22 page
The stellar mass ratio of GK Persei
We study the absorption lines present in the spectra of the long-period
cataclysmic variable GK Per during its quiescent state, which are associated
with the secondary star. By comparing quiescent data with outburst spectra we
infer that the donor star appears identical during the two states and the inner
face of the secondary star is not noticeably irradiated by flux from the
accreting regions. We obtain new values for the radial velocity semi-amplitude
of the secondary star, Kk = 120.5 +- 0.7 km/s, a projected rotational velocity,
Vksin i = 61.5 +- 11.8 km/s and consequently a measurement of the stellar mass
ratio of GK Per, q = Mk/Mwd = 0.55 +- 0.21. The inferred white dwarf radial
velocities are greater than those measured traditionally using the wings of
Doppler-broadened emission lines suspected to originate in an accretion disk,
highlighting the unsuitability of emission lines for mass determinations in
cataclysmic variables. We determine mass limits for both components in the
binary, Mk >= 0.48 +- 0.32 Msolar and Mwd >= 0.87 +- 0.24 Msolar.Comment: 8 pages, 8 figures, accepted by MNRA
Micro-LED nanosecond pulsed structured light sources with 405 nm – 510 nm wavelength
Narrow-pulse visible light sources are crucial to time-resolved imaging. We present 16k-element MicroLED arrays spanning the visible region allowed by InGaN/GaN, achieving 3 ns pulses at up to 100 MHz repetition rate with programmable illumination patterns
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