2,279 research outputs found
The Z(4430) and a New Paradigm for Spin Interactions in Tetraquarks
Following the recent confirmation of the Z+(4430) resonance with
J^{PG}=1^{++}, we have re-examined the model of S- and P-wave tetraquarks. We
propose a `type-II' diquark-antidiquark model which shows to be very effective
at producing a simple and comprehensive picture of the J^{PG}=1^{++} and 1^{--}
sectors of the recently discovered charged tetraquarks and of the observed Y
resonances. The model is still faced with the unresolved difficulty of
explaining why some states seem to have incomplete isospin multiplets.Comment: 17 pages, 1 figure, comments added, typos corrected, to appear in
Phys Rev
Four-Quark Mesons
The features of a model interpreting the light scalar mesons as
diquark-antidiquark bound states and the consequences of its natural extension
to include heavy quarks are briefly reviewed.Comment: Talk given at the 6th Conference on Quark Confinement and the Hadron
Spectrum, Villasimius, Sardinia, Italy, 21-25 Sep 200
Four Quark Interpretation of Y(4260)
We propose that the Y(4260) particle recently announced by BaBar is the first
orbital excitation of a diquark-antidiquark state ([cs][cbar sbar]). Using
parameters recently determined to describe the X(3872) and X(3940) we show that
the Y mass is compatible with the orbital excitation picture. A crucial
prediction is that Y(4260) should decay predominantly in D_s D_sbar. The
Y(4260) should also be seen in B non-leptonic decays in association with one
kaon. We consider the full nonet of related four-quark states and their
predicted properties. Finally, we comment on a possible narrow resonance in the
same channel.Comment: 3 pages, 2 figures, RevTex, Revised discussion of the Y mas
Which affects affect the use of new technologies? Italian adaptation of the Internet Motive Questionnaire for Adolescents (IMQ-A) and criterion validity with problematic use and body dissatisfaction
Given the negative role of problematic use of new technological devices (NTD) in behavioral and psychological domains, the aim of the study is the Italian adaptation and validation of the Internet Motive Questionnaire for Adolescents (IMQ-A) in order to understand the motivation for the use of NTD. A total of 769 students 10-19 aged (M = 13.22, SD = 1.56) completed the IMQ-A, the Collins Figures Rating Scale, and two measures regarding the problematic NTD use, focused on overuse during the night and during meals. The IMQ-A showed adequate internal consistency with regard to its four subscales: Coping (α = .84), Social (α = .80), Enhancement (α = .80), and Conformity (α = .68) motives. However, with regard to factorial structure, a threefactor model (excluding Conformity subscale) showed slightly better fit indices than the original model. Coping motive was correlated with problematic NTD use and succeeded in predicting higher scores in body dissatisfaction as evidence of criterion-related and external validity. The Italian adaptation of the IMQ-A can be useful in both research and clinical fields, in order to propose alternative strategies for coping to users and to improve emotion regulation facets
Is the anomalous decay ratio of D_{sJ}(2632) due to isospin breaking?
Quark pair annihilation into gluons is suppressed at large momenta due to the
asymptotic freedom. As a consequence, mass eigenvalues of heavy states should
be almost diagonal with respect to up and down quark masses, thereby breaking
isospin. We suggest the particle observed by the SELEX Collaboration,
D_{sJ}(2632) to be to a good extent a [cd][dbar sbar] state, which would
explain why its D^0 K^+ mode is anomalously suppressed with respect to D_s eta.
Predictions for the rates of the yet unobserved modes D_s pi^0 and D^+ K^0 are
given.Comment: 3 pages, 1 figur
The momentum distribution of J/psi in B decays
The discrepancy between theory and data in the momentum distribution of slow
J/psi in B decays has been several times addressed as a puzzle. Using the most
recent results on exclusive B decays into J/psi and heavy kaons or exotic
mesons and reconsidering the non-relativistic-QCD calculation of the color
octet fragmentation component, we show that an improvement in the comparison
between data and theory can be obtained. There is still room for a better fit
to data and this may imply that new exotic mesons of the XYZ kind have yet to
be discovered.Comment: 4 pages, 2 figures, 2 tables. To appear in Physical Review
Four-Quark Mesons in Non-leptonic B Decays--Could They Resolve Some Old Puzzles?
We point out that non-leptonic B decays driven by b-->ccbar s should provide
a favourable environment for the production of hidden charm diquark-antidiquark
bound states that have been suggested to explain the resonances with masses
around 4 GeV recently observed by BaBar and BELLE. Studying their relative
abundances in non-leptonic B decays can teach us novel lessons about their
structure and the strong interactions. Through their decay into psi they can
provide a natural explanation of the excess of B-->psi X observed for p_psi < 1
GeV. Other phenomenological consequences are mentioned as well.Comment: 6 pages, 2 figures, revte
Comment on `Note on X(3872) production at hadron colliders and its molecular structure'
We briefly comment on the paper by Albaladejo et al. [arXiv:1709.09101],
rejecting its conclusions.Comment: This paper was prepared at the request of a journal editor. 3 Pages,
no figure
The observation of light nuclei at ALICE and the X(3872) conundrum
The new data reported by ALICE on the production of light nuclei with pT < 10
GeV in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV are used to compute an
order-of-magnitude estimate of the expected production cross sections of light
nuclei in proton-proton collisions at high transverse momenta. We compare the
hypertriton, helium-3 and deuteron production cross sections to that of
X(3872), measured in prompt pp collisions by CMS. The results we find suggest a
different production mechanism for the X(3872), making questionable any loosely
bound molecule interpretation.Comment: 5 pages, 2 figures. Version accepted on PR
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