7,117 research outputs found
Quarkonium production and decays
Quarkonium decays are studied in the charmonium model. Relativistic
corrections, higher-order perturbative QCD corrections and non- perturbative
contributions are discussed. Recent measurements of charmonium annihilation
rates are used to evaluate the strong coupling constant
simultaneously with the wave functions (and their derivatives) at the origin.
Further predictions are made for yet unobserved decay rates. The various models
for quarkonium production in hadronic collisions are critically reviewed. Based
on the charmonium model, the cross sections of different quarkonium states are
given in a well-defined QCD perturbation series, including quark--antiquark,
quark--gluon, and gluon--gluon scatterings. Numerical estimates are given for
charmonium production in \p\p, \ppbar, and \pi\p collisions. The role of
indirect \JP production via , \eta_{\c}(2S),
and \b-decays is pointed out. Relativistic effects and non-perturbative
contributions are found to be important. Existing measurements are compiled and
shown to be well explained if all contributions are included. The
cross section is calculated in complete next-to-leading order. Finally, a study
of the high-energy behaviour of quarkonium cross sections is made, based on the
asymptotical behaviour of higher-order QCD corrections.Comment: 128 pages, compressed ps file available via anonymous ftp to
darssrv1.cern.ch: cern/9402/th-7170-94.ps.Z, CERN-TH.7170/9
Radiative corrections to scattering
We investigate the effects of photon radiation on deep-inelastic \re\gamma
scattering. Depending on the set of variables chosen, we find appreciable
effects in the kinematic region accessible at LEP2. Convenient analytic results
for corrected differential cross sections are presented.Comment: 9 pages, latex + 1 postscript figure, all uuencode
Model-independent QED corrections to photon structure-function measurements
We present the first calculation of QED radiative corrections to
deep-inelastic electron-photon scattering in terms of those variables that are
reconstructed in measurements of the photon structure function in
electron-positron collisions. In order to cover the low- region, we do not
invoke the QCD-improved parton model but rather express our results in terms of
the photon structure functions. Both analytical and numerical results are
given.Comment: Latex, 8 pages, 3 figures, uses epsfig.sty, 12pt.st
Central production of mesons: Exotic states versus Pomeron structure
We demonstrate that the azimuthal dependence of central meson production in
hadronic collisions, when suitably binned, provides unambiguous tests of
whether the Pomeron couples like a conserved vector-current to protons. We
discuss the possibility of discriminating between q-qbar and glueball
production in such processes. Our predictions apply also to meson production in
tagged two-photon events at electron--positron colliders and to vector-meson
production in ep collisions at HERA.Comment: 15 pages, latex, no figur
Models for Photon-photon Total Cross-sections
We present here a brief overview of recent models describing the
photon-photon cross-section into hadrons. We shall show in detail results from
the eikonal minijet model, with and without soft gluon summation.Comment: 7 pages, 5 figures, laTeX, requires espcrc2.sty. To appear in the
Proceedings of Photon-99, Freiburg, 23 -27 May 99, labels in the figures
1,3,4,5 corrected, one typo in an equation correcte
Perception of profile appearance as judged by peers using 3D video imaging
The purpose of this study was to investigate the social perceptions of subjects with differing lip position and facial convexity in three dimensions. A 3dMD camera (3dMD, Atlanta, GA) was used to capture 3D images of 9 subjects’ faces. The images were altered to have ideal lip position and ideal convexity, ideal lip position and Class II convexity, Class II lip position and ideal convexity, and Class II lip position and Class II convexity. 400 laypersons rated their perceptions of the subjects’ athletic ability, popularity, leadership, and intelligence on a VAS scale. Subjects with ideal lip position relative to the E-line were rated significantly higher for leadership and intelligence. Males with ideal facial convexity were judged to be better leaders and more intelligent than those with Class II convexity. Subjects with ideal lip position were given the highest mean VAS scores for all four social attributes. The perception of differences related to facial convexity was inconsistent
Continuing Criminal Enterprise, Conspiracy, and the Multiple Punishment Doctrine
This Note argues that the Multiple Punishment Doctrine prohibits the imposition of concurrent convictions and sentences upon criminal defendants found guilty of engaging in a CCE and conspiring to violate narcotics laws. Part I surveys the values underlying the Multiple Punishment Doctrine and traces the evolution of the Supreme Court\u27s application of the doctrine to modern criminal law. Part II examines the various methods employed by the circuit courts of appeals to deal with simultaneous convictions and sentences for CCE and conspiracy. Part III reviews the test, identified in Part I, that the Supreme Court has implicitly utilized to analyze Multiple Punishment Claims and evaluates CCE and conspiracy convictions under this standard. This Note concludes that the majority approach - mandating the vacation of conspiracy convictions and sentences obtained simultaneously with a CCE conviction - is the only method utilized by the courts of appeals that comports with the Multiple Punishment Doctrine
Testing factorization of charmonium production
Within the NRQCD factorization approach the production of heavy quarkonia can
be calculated in perturbative QCD in terms of a few
production-process-independent NRQCD matrix elements. We test the universality
of these long-distance matrix elements by comparing their values as determined
from charmonium production at p pbar, e p, and e+ e- colliders, and in Z^0,
Upsilon, and B decays.Comment: 19 pages, latex, 4 figure
Project Vestia: Habitation of the Future
The future of interplanetary habitation will be built through the use of Inflatable Habitat Modules, or IHMs. Though previously theorized, recent developments in material science and manufacturing processes have allowed IHMs to be lighter, smaller, and more durable than any hard-shell module with the same deployment size. However, the one problem that has not yet been tackled is providing a floor for terrestrial counterparts in the otherwise rounded modules. Project Vestia aims to design and create a full-scale, functional build of a collapsible floor made of individual panels which would fold during transit using methods similar to origami. Utilizing these methods, the floor will be able to collapse from 4 meters by 10 meters once deployed to 3 meters by a quarter meter thick. When extended, the floor will be capable of supporting 20,000 earth-equivalent pounds on the Martian surface (7,500 pounds on earth), and will weigh less than a half a ton. This system is optimized such that the SpaceX Starship launch vehicle would be capable of shipping 48 of these condensed habitats, which would contain the equivalent living space of over 17 times the habitable volume of the ISS. This new system will pave the way for future astronauts, both public and private, to inhabit worlds beyond our imagination. This project is in its early stages of securing funding and design, and will be moving into final design and construction by March of 2021
Photon Total Cross-sections
We discuss present predictions for the total and
cross-sections, highlighting why predictions differ. We present results from
the Eikonal Minijet Model and improved predictions based on soft gluon
resummation.Comment: 7 pages, 10 figures, LaTeX, requires espcrc2.sty, Talk presented by
G. Pancheri at PHOTON-2003, International Meeting on Structure and
Interactions of the Photon, Frascati, Italy, April 7-11, 200
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