Author:
Tan Wei-Han,Yang Hui-Min,Chen Hua-Xing
Abstract
AbstractThe methods of QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory have been widely applied to study the singly heavy baryons, and especially, we have applied these methods to predict not only the mass and width of the $$\varXi _b(6087)^0$$
Ξ
b
(
6087
)
0
recently discovered by LHCb, but also its observation channel and its mass difference from the $$\varXi _b(6100)^-$$
Ξ
b
(
6100
)
-
. We apply the same approach to perform a complete study on the P-wave bottom baryons of the SU(3) flavor $${\bar{\textbf{3}}}_F$$
3
¯
F
and investigate their fine structure. Besides the $$\varLambda _b(5912)^0$$
Λ
b
(
5912
)
0
, $$\varLambda _b(5920)^0$$
Λ
b
(
5920
)
0
, $$\varXi _b(6087)^0$$
Ξ
b
(
6087
)
0
, and $$\varXi _b(6100)^-$$
Ξ
b
(
6100
)
-
, our results suggest the existence of the other two $$\varLambda _b$$
Λ
b
and two $$\varXi _b$$
Ξ
b
baryons, whose widths are limited. They are the $$\varLambda _b(J^P = 3/2^-)$$
Λ
b
(
J
P
=
3
/
2
-
)
with the mass and width about $$(5.93^{+0.13}_{-0.13}~\textrm{GeV},\,0.0^{+12.0}_{-~0.0}~\textrm{MeV})$$
(
5
.
93
-
0.13
+
0.13
GeV
,
0
.
0
-
0.0
+
12.0
MeV
)
, the $$\varLambda _b(5/2^-)$$
Λ
b
(
5
/
2
-
)
with $$(5.94^{+0.13}_{-0.13}~\textrm{GeV},\,\approx 0~\textrm{MeV})$$
(
5
.
94
-
0.13
+
0.13
GeV
,
≈
0
MeV
)
, the $$\varXi _b(3/2^-)$$
Ξ
b
(
3
/
2
-
)
with $$(6.10^{+0.15}_{-0.10}~\textrm{GeV},\, 1.4{^{+11.6}_{-~1.4}}~\textrm{MeV})$$
(
6
.
10
-
0.10
+
0.15
GeV
,
1.4
-
1.4
+
11.6
MeV
)
, and the $$\varXi _b(5/2^-)$$
Ξ
b
(
5
/
2
-
)
with $$(6.11^{+0.15}_{-0.10}~\textrm{GeV},\,1.0{^{+7.4}_{-1.0}}~\textrm{MeV})$$
(
6
.
11
-
0.10
+
0.15
GeV
,
1.0
-
1.0
+
7.4
MeV
)
. Their mass splittings are calculated to be $$M_{\varLambda _b(5/2^-)} - M_{\varLambda _b(3/2^-)} = 17\pm 7~\textrm{MeV}$$
M
Λ
b
(
5
/
2
-
)
-
M
Λ
b
(
3
/
2
-
)
=
17
±
7
MeV
and $$M_{\varXi _b(5/2^-)} - M_{\varXi _b(3/2^-)} = 14\pm 7~\textrm{MeV}$$
M
Ξ
b
(
5
/
2
-
)
-
M
Ξ
b
(
3
/
2
-
)
=
14
±
7
MeV
. All these baryons are explained as the P-wave bottom baryons of the $$\rho $$
ρ
-mode, where the orbital excitation is between the two light quarks. However, the existence of this mode is still controversial, so their experimental searches can verify both our approach and the existence of the $$\rho $$
ρ
-mode, which can significantly improve our understanding on the internal structure of hadrons.
Funder
Jiangsu Provincial Double-Innovation Program
National Natural Science Foundation of China
Fundamental Research Funds for the Central Universities
Publisher
Springer Science and Business Media LLC