Data on open-charm channels collected by the Belle Collaboration are analyzed simultaneously using a unitary approach based on a coupled-channel model in a wide energy range √s = 3.7–4.7 GeV. The ...resulting fit provides a remarkably good overall description of the line shapes in all studied channels. The parameters of five vector charmonium resonances are extracted from the fit.
X (3915) as a tensor D ∗ D ¯∗ molecule Baru, V.; Hanhart, C.; Nefediev, A. V.
EPJ Web of Conferences,
2019, Letnik:
218
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Two-photon decays of a tensor
D
∗
D
¯
∗
molecule are studied and the suggested approach is applied to the
X
(3915) charmonium-like state under the assumption of the latter being a 2
++
molecule — a ...spin partner of the
X
(3872). It is argued that the existing experimental data disfavour such an identification of this state. Therefore, it is suggested that either the
X
(3915) has a different exotic nature or it has to be identified as a scalar.
We explore the quark-mass dependence of the pole position of the X(3872) state within the molecular picture. The calculations are performed within the framework of a nonrelativistic Faddeev-type ...three-body equation for the DD¯π system in the JPC=1++ channel. The πD interaction is parametrised via a D⁎ pole, and a three-body force is included to render the equations well defined. Its strength is adjusted such that the X(3872) appears as a DD¯⁎ bound state 0.5 MeV below the neutral threshold. We find that the trajectory of the X(3872) depends strongly on the assumed quark-mass dependence of the short-range interactions which can be determined in future lattice QCD calculations. At the same time we are able to provide nontrivial information on the chiral extrapolation in the X channel.
The heavy-quark spin symmetry (HQSS) partners of the X(3872) molecule are investigated in a chiral effective field theory (EFT) approach which incorporates contact and one-pion exchange interactions. ...The integral equations of the Lippmann-Schwinger type are formulated and solved for the coupled-channel problem for the DD̄, DD̄*, and D*D̄* systems with the quantum numbers JPC = 1++, 1+−, 0++, and 2++. We confirm that, if the X(3872) is a 1++DD̄* molecular state then, in the strict heavy-quark limit, there exist three partner states, with the quantum numbers 1+−, 0++, and 2++, which are degenerate in mass. At first glance, this result looks natural only for the purely contact pionless theory since pions contribute differently to different transition potentials and, therefore, may lift the above degeneracy. Nevertheless, it is shown that, by an appropriate unitary transformation, the Lippmann-Schwinger equation in each channel still can be brought to a block-diagonal form, with the same blocks for all quantum numbers, so that the degeneracy of the bound states in different channels is preserved. We stress that neglecting some of the coupled-channel transitions in an inconsistent manner leads to a severe violation of HQSS and yields regulator-dependent results for the partner states. The effect of HQSS violation in combination with nonperturbative pion dynamics on the pole positions of the partner states is discussed.
In this work, using multi-parameter harmonic analysis and expansion of altimetry into spherical functions, models of the Moon's physical surface (digital lunar selenocentric map - DLSM) are built, ...and a comparison of similarity of chosen local areas of the complex lunar structure is performed. The constructed DLSM have radius-vectors of the surface points in accordance with the space measurements taken. As result, the averaged fractal dimension of the selenocentric surfaces profiles models was found to 1.345. The similarity and difference parameters were determined by the author's method using fractal similarity coefficients. The analysis of macrosurfaces based on multi-parameter and fractal methods for the selenocentric models built in this work has not been conducted before.
This paper aims at the creation of a selenocentric catalogue of lunar objects' positions (SCLOP) and development of a theoretical simulation model of orbital referencing of lunar objects taken by ...space lunar satellite to the selenocentric coordinate system defined by SCLOP. The data produced by the modern space lunar missions serve as the basis for multi-parameter and highly accurate digital simulation model. The results obtained in the work are important and relevant for the development of navigation technologies on creation and orienting of coordinate systems and the study of celestial bodies' figures. To solve the problems stated in this work, the following new results are produced: a) reliability of coordinate data in modern systems of coordinate and time support for lunar objects is investigated by the robust analysis; b) a method and a software complex for transforming selenographic coordinates (TSC) are developed; c) the software package is tested for work with navigation data and determining planetary parameters; d) a method of adaptive regression modeling (ARM) for transforming coordinate systems and assessing structures and parameters of the selenocentric system (SS) is created; e) an algorithm of multi-parameter identification of SS based on ARM-approach is developed to carry out works on expansion and estimation of the reference selenocentric system; f) a global dynamic selenocentric system is constructed on the basis of optical observations taken at "Clementine", "LRO", and "Apollo" missions; g) as a result, a simulation digital model of orbital referencing of lunar objects optical observations, taken by star sensors of lunar satellite and on-board laser interferometer, to the selenocentric coordinate system is developed.
The most recent experimental data for the decays of the vector bottomonium γ(10860) proceeding through the formation of the states
Z
b
(10610) and
Z
b
(10650) are analysed simultaneously using ...solutions of the Lippmann-Schwinger equations which respect constraints from unitarity and analyticity. The interaction potential in the open-bottom channels $ {B^{(*)}}{\bar B^*} $ contains short-range interactions as well as the one-pion exchange; both types of the interaction are taken into account fully nonperturbatively. This way, all parameters of the interaction are fixed directly from the data and the pole positions for the
Z
b
’s are determined as a prediction. In particular, both
Z
b
states are found to be described by resonance poles located on the unphysical Riemann sheets in the vicinity of the corresponding thresholds. The heavy quark spin symmetry (HQSS) is employed to predict, in a parameter-free way, the pole positions and the line shapes in the elastic and inelastic channels for the
Z
b
s’ spin partner states
W
bJ
with the quantum numbers
J
++
(
J
= 0, 1, 2). Such spin partners can be produced in radiative decays of the vector bottomonium Υ(10860) and are expected to be detected in the Belle-II experiment.
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