Abstract
AbstractInspired by the observation of the X(6900) by LHCb and the X(6600) (with mass $$6552\pm 10\pm 12$$
6552
±
10
±
12
MeV) recently by CMS and ATLAS experiments of the LHC in the di-$$J/\varPsi $$
J
/
Ψ
invariant mass spectrum, we systemically study masses of all ground-state configurations of the hidden heavy-flavor tetraquarks $$q_{1}Q_{2}{\bar{q}}_{3}{\bar{Q}}_{4}$$
q
1
Q
2
q
¯
3
Q
¯
4
and $$Q_{1}Q_{2}{\bar{Q}}_{3}{\bar{Q}}_{4}$$
Q
1
Q
2
Q
¯
3
Q
¯
4
$$(Q=c,b$$
(
Q
=
c
,
b
; $$q=u,d,s)$$
q
=
u
,
d
,
s
)
containing two and four heavy quarks in the MIT bag model with chromomagnetic interaction and enhanced binding energy. Considering color-spin mixing due to chromomagnetic interaction, our mass computation indicates that the observed X(6600) is likely to be the $$0^{++}$$
0
+
+
ground states of hidden-charm tetraquark $$cc{\bar{c}}{\bar{c}}$$
c
c
c
¯
c
¯
with computed masses 6572 MeV, which has a $$0^{++}$$
0
+
+
color partner around 6469 MeV. The fully bottom system of tetraquark $$bb{\bar{b}}{\bar{b}}$$
b
b
b
¯
b
¯
has masses of 19685 MeV and 19717 MeV for the $$0^{++}$$
0
+
+
ground states. Further calculation of the tetraquark systems $$sc{\bar{s}}{\bar{c}}$$
s
c
s
¯
c
¯
, $$sb{\bar{s}}{\bar{b}}$$
s
b
s
¯
b
¯
, $$cb{\bar{c}}{\bar{b}}$$
c
b
c
¯
b
¯
, $$nc{\bar{n}}{\bar{c}}$$
n
c
n
¯
c
¯
and $$nb{\bar{n}}{\bar{b}}$$
n
b
n
¯
b
¯
shows that $$Z_{c}(4200)$$
Z
c
(
4200
)
is a $$1^{+-}$$
1
+
-
state of tetraquark $$nc{\bar{n}}{\bar{c}}$$
n
c
n
¯
c
¯
and Z(4020) is a $$1^{+-}$$
1
+
-
state of tetraquark $$nc{\bar{n}}{\bar{c}}$$
n
c
n
¯
c
¯
with a mass of 4079 MeV. All of these tetraquarks are above their lowest thresholds of two mesons and unstable against the strong decays.
Funder
National Natural Science Foundation of China
Publisher
Springer Science and Business Media LLC
Subject
Physics and Astronomy (miscellaneous),Engineering (miscellaneous)
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