1,722,468 research outputs found
Mass spectrum of fully charmed tetraquarks
Full text linkThere are three and seven fully charmed
tetraquarks, the mass spectrum from to excitations is calculated in a
non-relativistic quark potential model. In the calculation, the interactions
among four internal quarks/antiquark are approximated as a dominant color
interaction between a diquark and an antidiquark, and a residual interaction
responsible for the diquark/antidiquark cluster effect. The color interaction
between the diquark and the antidiquark is characterized by the conventional
Cornell potential, while the residual interaction is modeled as the Yukawa-type
scalar and vector boson exchange potentials. In the numerical
results, though the scalar and vector boson exchange
interactions reduce the masses of wave tetraquarks
MeV, they contribute to the masses of other
tetraquarks small. The mass splittings of tetraquarks
between different multiplets and within the same multiplet are smaller than
those in charmonium, and the splittings are affected by the scalar or
vector boson exchange interactions small. Our calculations suggest
that the observed , and should be different radial
excitations of . The measurements of the quantum
numbers and the mass splittings will be helpful to identify and understand of
the candidates.Comment: 9 pages, 5 tables, PDFLate
The possible tetraquark states observed by the LHCb experiment
No full textWe give a brief comment on the possible tetraquark states observed by the LHCb experiment
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Investigating full-heavy tetraquarks composed of and
Full text linkThe full-heavy tetraquarks and are
systematically investigated within the chiral quark model. The meson-meson
structure, diquark-antidiquark structure and K-structure are considered in this
work. There is no bound state for and
systems in and channels. However, for
system, three possible resonance states with energy of , and are found in and , respectively, and their decay width are , and . For system, there also exist three possible resonance
states with energy of , and in and , respectively, and the decay
widths of them are , and
. and systems will
have the same results as and ,
respectively. These full-heavy resonance states are worthy to be searched in
the future experiments.Comment: 10 pages, 9 figure
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Bar-C Ranch P.2
No full textSteamboat Rock and the old ranch house at Bar-C Ranch. Picture taken 1934. Charles Kelly, donor
Fully Charmed Tetraquark States in Color Structure via QCD Sum Rules
Full text linkStimulated by the recent experimental results on the fully-charm tetraquark states, we systematically calculate the mass spectra of the fully-charm tetraquark states in color configuration via QCD sum rules. By constructing nine type currents with quantum numbers and , we perform analytic calculation up to dimension six in the Operator Product Expansion (OPE). We find the fully-charm tetraquark states with lie around 6.48 6.62 GeV while the fully-charm tetraquark states with are about 6.85 7.02 GeV. Notably, the mass predictions for the tetraquarks, specifically those with , align with the broad structure identified by LHCb. Moreover, the masses of fully-charm tetraquarks with and are anticipated to match closely with the mass of X(6900), considering the margin of error. Such findings hint at the presence of some components within the di- structures observed by LHCb. The predictions for tetraquark states with may be accessible in the future BelleII, Super-B, PANDA, and LHCb experiments.19 pages, 4 figures, 1 table. To match the published versio
Bar-C Ranch P.1
No full textRanch house at Bar-C Ranch in Hole-in-the-Wall, Wyoming, where Butch Cassidy often stopped
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