309 research outputs found
The polarization of Lyman alpha radiation produced in charge transfer collisions between protons and the inert gases
Polarization of Lyman alpha radiation in proton collisions with helium, argon, and neon atom
The polarization of Lyman alpha radiation produced by direct excitation of hydrogen atoms by proton impact
Lyman alpha radiation measurement in collision between protons and hydrogen atom
Electron-impact excitation of the (5d106s)2S1/2-(5d106p)2P1/2,3/2 resonance transitions in gold atoms
Results from a joint experimental and theoretical investigation of electron-impact excitation of the (5 d10 6s) S2 1/2 → (5 d10 6p) P2 1/2,3/2 resonance transitions in gold atoms are presented. The calculations were performed using three fully relativi
Constraining the Hadronic Contributions to the Muon Anomalous Magnetic Moment
The mini-proceedings of the Workshop on "Constraining the hadronic
contributions to the muon anomalous magnetic moment" which included the "13th
meeting of the Radio MonteCarLow WG" and the "Satellite meeting R-Measurements
at BES-III" held in Trento from April 10th to 12th, 2013, are presented. This
collaboration meeting aims to bring together the experimental e+e- collider
communities from BaBar, Belle, BESIII, CMD2, KLOE, and SND, with theorists
working in the fields of meson transitions form factors, hadronic contributions
to (g-2)_\mu and effective fine structure constant, and development of Monte
Carlo generator and Radiative Corrections for precision e+e- and tau physics.Comment: 45 pages, 17 contributions. Editors: P. Masjuan and G. Venanzon
Generalized oscillator strength for Na 3s-3p transition
Generalized oscillator strengths (GOS's) for the Na transition have
been investigated using the spin-polarized technique of the random phase
approximation with exchange (RPAE) and the first Born approximation (FBA),
focussing our attention on the position of the minimum. Intershell correlations
are found to influence the position of the minimum significantly, but hardly
that of the maximum. The RPAE calculation predicts for the first time the
positions of the minimum and maximum at momentum transfer, values of 1.258
a.u. and 1.61 a.u., respectively. The former value is within the range of
values extracted from experimental measurements, a.u.. We
recommend careful experimental search for the minimum around the predicted
value for confirmation.Comment: 11 pages, 2figure
Heavy Quarkonium Physics
This report is the result of the collaboration and research effort of the
Quarkonium Working Group over the last three years. It provides a comprehensive
overview of the state of the art in heavy-quarkonium theory and experiment,
covering quarkonium spectroscopy, decay, and production, the determination of
QCD parameters from quarkonium observables, quarkonia in media, and the effects
on quarkonia of physics beyond the Standard Model. An introduction to common
theoretical and experimental tools is included. Future opportunities for
research in quarkonium physics are also discussed.Comment: xviii + 487 pages, 260 figures. The full text is also available at
the Quarkonium Working Group web page: http://www.qwg.to.infn.i
Differential Cross Sections and Cross-Section Ratios for the Electron-Impact Excitation of the Neon 2p⁵3s Configuration
Electron-impact differential cross-section measurements for the excitation of the 2p53s configuration of Ne are reported. The Ne cross sections are obtained using experimental differential cross sections for the electron-impact excitation of the n = 2 levels of atomic hydrogen [Khakoo et al., Phys. Rev. A 61, 012701-1 (1999)], and existing experimental helium differential cross-section measurements, as calibration standards. These calibration measurements were made using the method of gas mixtures (Ne and H followed by Ne and He), in which the gas beam profiles of the mixed gases are found to be the same within our experimental errors. We also present results from calculations of these differential cross sections using the R-matrix and unitarized first-order many-body theory, the distorted-wave Born approximation, and relativistic distorted-wave methods. Comparison with available experimental differential cross sections and differential cross-section ratios is also presented
Direct versus indirect detection in mSUGRA with self-consistent halo models
We perform a detailed analysis of the detection prospects of neutralino dark
matter in the mSUGRA framework. We focus on models with a thermal relic
density, estimated with high accuracy using the DarkSUSY package, in the range
favored by current precision cosmological measurements. Direct and indirect
detection rates are computed implementing two models for the dark matter halo,
tracing opposite regimes for the phase of baryon infall, with fully consistent
density profiles and velocity distribution functions. This has allowed, for the
first time, a fully consistent comparison between direct and indirect detection
prospects. We discuss all relevant regimes in the mSUGRA parameter space,
underlining relevant effects, and providing the basis for extending the
discussion to alternative frameworks. In general, we find that direct detection
and searches for antideuterons in the cosmic rays seems to be the most
promising ways to search for neutralinos in these scenarios.Comment: 26 pages, 9 figure
Top quark physics in hadron collisions
The top quark is the heaviest elementary particle observed to date. Its large
mass makes the top quark an ideal laboratory to test predictions of
perturbation theory concerning heavy quark production at hadron colliders. The
top quark is also a powerful probe for new phenomena beyond the Standard Model
of particle physics. In addition, the top quark mass is a crucial parameter for
scrutinizing the Standard Model in electroweak precision tests and for
predicting the mass of the yet unobserved Higgs boson. Ten years after the
discovery of the top quark at the Fermilab Tevatron top quark physics has
entered an era where detailed measurements of top quark properties are
undertaken. In this review article an introduction to the phenomenology of top
quark production in hadron collisions is given, the lessons learned in Tevatron
Run I are summarized, and first Run II results are discussed. A brief outlook
to the possibilities of top quark research a the Large Hadron Collider,
currently under construction at CERN, is included.Comment: 84 pages, 32 figures, accepted for publication by Reports on Progress
in Physic
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