关于新铵态物质的更多信息
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Research Article
More about the Mass of the New Charmonium States
T. M. Aliev,
1,2
H. ÖzGahin,
1
and M. SavcJ
1
1
Physics Department, Middle East Technical University, 06800 Ankara, Turkey
2
Institute of Physics, Baku, Azerbaijan
Correspondence should be addressed to M. Savcı; savci@metu.edu.tr
Received 13 November 2014; Revised 20 January 2015; Accepted 20 January 2015
Academic Editor: Chao-Qiang Geng
Copyright © 2015 T. M. Aliev et al. is is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. e
publication of this article was funded by SCOAP
3
.
If (3872)is described by the picture as a mixture of the charmonium and molecular
∗
states; (3940)as a mixture of the
𝑐0
and
∗
∗
states; and (4260)as a mixture of the tetraquark and charmonium states, their orthogonal combinations should also
exist. We estimate the mass and residues of the states within the QCD sum rules method. We nd that the mass splitting among
, and their orthogonal states is at most 200 MeV. Experimental search of these new states can play critical role for establishing
the nature of the new charmonium states.
1. Introduction
Last decade was quite an exciting and productive period
in particle physics. Starting from the rst observation of
the (3872) mesonbytheBelleCollaboration[1]upto
now more than twenty new charmonium states have been
observed (for the experimental and theoretical reviews and
the references to the original works on the charmonium
spectroscopy, see, e.g., [2–8]). e main lesson from these
discoveries is that these states (referred to as states)
can not be described by the simple quark model, that is,
as a quark-antiquark system, and they are believed to have
more complex structures. Understanding the structure and
dynamics of these states is one of the hot problems in particle
physics. In investigating the properties of these states two
pictures are widely used, namely, four-quark (tetraquark) or
meson molecules (bound states of two mesons).
e mass and some of the strong coupling constants of
the mesons with light mesons are widely studied within
the QCD sum rules method [9] in many works (see, e.g.,
[10, 11]). e rst calculation of the mass of the (3872)
meson as a tetraquark state with the quantum numbers
𝑃𝐶
=1
++
is performed within QCD sum rules method in
[10]. e (3872)meson as a
∗
molecular state with the
interpolating current,
mol
𝜇
=
1
2
𝑎
5
𝑎
𝑏
𝜇
𝑏
−
𝑎
𝜇
𝑎
𝑏
5
𝑏
,
(1)
was investigated in [11]. e next step in analysis of the
properties of (3872)is that it is assumed to be a mixture
of the charmonium and
∗
molecules [12, 13], whose
interpolating current has the form
(1)
𝜇
=cos
1
ch
𝜇
+sin
1
mol
𝜇
,
(2)
where
ch
𝜇
=
1
6
2
𝜇
5
(3)
and
mol
𝜇
is given in (1).In[12, 13], the mixing angle is
calculated to have the value
1
=(9±4)
0
in order to reproduce
the experimental value of the mass of the (3872)meson.
As far as the the state (3940)is concerned, it is described
by the mixture of the scalar
𝑐0
and
∗
∗
molecules [14]. In
other words its interpolating current can be written as
(2)
=cos
2
−
2
+sin
2
𝜇
𝜇
.
(4)
Hindawi Publishing Corporation
Advances in High Energy Physics
Volume 2015, Article ID 728098, 7 pages
http://dx.doi.org/10.1155/2015/728098
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