The full-heavy tetraquarks
b
b
b
¯
b
¯
and
c
c
c
¯
c
¯
are systematically investigated within the chiral quark model and the quark delocalization color screening model. Two structures, meson–meson ...and diquark–antidiquark, are considered. For the full-beauty
b
b
b
¯
b
¯
systems, there is no any bound state or resonance state in two structures in the chiral quark model, while the wide resonances with masses around
19.1
-
19.4
GeV and the quantum numbers
J
P
=
0
+
,
1
+
, and
2
+
are possible in the quark delocalization color screening model. For the full-charm
c
c
c
¯
c
¯
systems, the results are qualitative consistent in two quark models. No bound state can be found in the meson–meson configuration, while in the diquark–antidiquark configuration there may exist the resonance states, with masses range between 6.2 to 7.4 GeV, and the quantum numbers
J
P
=
0
+
,
1
+
, and
2
+
. And the separation between the diquark and the antidiquark indicates that these states may be the compact resonance states. The reported state
X
(6900) is possible to be explained as a compact resonance state with
I
J
P
=
00
+
in present calculation. All these full-charm resonance states are worth searching in the experiments further.
Motivated by the very recent observations of hidden charm pentaquarks Pc(4312)+, Pc(4440)+ and Pc(4457)+ of the LHCb Collaboration, we systematically study the spectra of the doubly-heavy (with or ...without charm/bottom numbers) pentaquarks and tetraquarks in non-relativistic constituent quark model. The model independent variational method is employed to solve the Schrödinger equation, where the test radial functions adopted are symmetric for the light quarks. In our study, the Pc(4312)+ may be assigned as the ground state with spin-parity 12− or 32−, while the Pc(4440)+ and Pc(4457)+ may be assigned as the excited states with 12−, which might all belong to the sextet with scc¯=1 and sℓ=32. It is notable that our working framework is quite similar to that of Hydrogen molecule, but with different potential structure. We also classify these pentaquarks and tetraquarks in light of the heavy quark symmetry and their decay properties are analyzed. Several promising channels for the observation of doubly-heavy pentaquarks and doubly-heavy tetraquarks in experiment are proposed.
Fully heavy dibaryons Huang, Hongxia; Ping, Jialun; Zhu, Xinmei ...
The European physical journal. C, Particles and fields,
09/2022, Letnik:
82, Številka:
9
Journal Article
Recenzirano
Odprti dostop
The existence of fully heavy dibaryons
Ω
ccc
Ω
bbb
,
Ω
ccb
Ω
bbc
,
Ω
ccc
Ω
ccc
, and
Ω
bbb
Ω
bbb
with
J
=
0
,
1
,
2
,
3
and
P
=
±
1
are investigated in the framework of a constituent quark model with ...the help of the resonating group method. The dibaryon composed of six
c
or
b
quarks with
J
P
=
0
+
is able to be bound, because the requirement for antisymmetrization between the same baryon clusters introduces an attractive interaction between two fully heavy baryons. Although it is difficult for the dibaryon with the color-singlet type
Ω
ccc
Ω
bbb
to form any bound state, it is possible for the
Ω
ccb
Ω
bbc
state to be bound. The channel coupling of all channels of both
Ω
ccb
Ω
bbc
and
Ω
ccc
Ω
bbb
structures leads to the bound conclusion of this fully heavy system composed of three
c
quarks and three
b
quarks.
Display omitted
► The Bi2O2CO3/Bi3NbO7 composite was in situ fabrication by hydrothermal methods. ► It showed largely enhanced visible-light photocatalytic destruction of E. coli. ► The ...heterostructures improved the electron–hole separations during photocatalysis. ► h+/OH radicals may be the main oxidative species during photocatalytic destruction.
The Bi2O2CO3/Bi3NbO7 (BiCO/BiNbO) composite was successfully fabricated by a simple hydrothermal method and found to be an effective visible-light-driven photocatalyst for inactivation of Escherichia coli (E. coli). The BiCO/BiNbO composite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), UV–vis diffuse reflectance spectrum (UV–vis DRS), and Fourier transform infrared (FT-IR) spectroscopy. The BiCO/BiNbO composite exhibited largely enhanced photocatalytic inactivation of E. coli as compared to the pure Bi3NbO7 under visible light irradiation. The enhanced photocatalytic performance can be attributed to the improved separation efficiency of the photogenerated holes and electrons. In addition, the possible bactericidal mechanism of the BiCO/BiNbO composite under visible light irradiation was discussed.
In the framework of the chiral quark model (ChQM), we systematically investigate the strange hidden-charm tetraquark systems
c
s
c
¯
u
¯
with two structures:
q
q
¯
-
q
q
¯
and
q
q
-
q
¯
q
¯
. The ...bound-state calculation shows that there is no any bound state in present work, which excludes the molecular state explanation (
D
0
D
s
∗
-
/
D
∗
0
D
s
-
/
D
∗
0
D
s
∗
-
) of the reported
Z
cs
(
3985
)
-
or
Z
cs
(
4000
)
+
. However, the effective potentials for the
c
s
-
c
¯
u
¯
systems show the possibility of some resonance states. By applying a stabilization calculation and coupling all channels of both two structures, two new resonance states are obtained, which are the
I
J
P
=
1
2
0
+
state with the energy around 4111–4116 MeV and the
I
J
P
=
1
2
1
+
state with energy around 4113–4119 MeV, respectively. Both of them are worthy of search in future experiments. Our results show that the coupling calculation between the bound channels and open channels is indispensable to provide the necessary information for experiments to search for exotic hadron states.
Inspired by the fully heavy tetraquark states reported by the LHCb, ATLAS and CMS Collaborations, we perform a systematical investigation of the low-lying fully heavy pentaquark systems composed of ...charm and bottom quarks (anti-quark) in the chiral quark model. With the help of the channel-coupling, we obtain several fully heavy pentaquark candidates, which are
c
c
c
c
b
¯
and
b
b
b
b
c
¯
systems with
J
P
=
1
/
2
-
and
3
/
2
-
,
c
c
c
b
c
¯
,
b
b
b
c
b
¯
,
c
c
c
b
b
¯
and
b
b
b
c
c
¯
systems with
J
P
=
5
/
2
-
. The binding energies of these states are all below 10 MeV and the root mean square (RMS) are around 1.8 fm, which indicates that these states are likely to be molecular states. These predicted exotic states may provide new ideas for experimental searches and we expect more experimental and theoretical researches to study and understand the fully heavy states in future.
Batch score control charts (
t
1) based on six NOC batches with control limits (±3 SD) dyed solid black line, and average trace marked by dotted black line: (a) batch 7, (b) batch 8, (c) batch 9, (d) ...batch 10.
Display omitted
► NIRS combined with MSPC was proposed for in-line monitoring of alcohol precipitation. ► MSPC control limits were established to detect and diagnose batch-to-batch variation. ► The method has proven to be a feasible PAT tool for monitoring batch evolution.
Alcohol precipitation is a critical unit operation during the manufacture of Chinese herbal injections. To facilitate enhanced process understanding and develop control strategy, the use of near-infrared spectroscopy (NIRS) combined with multivariate statistical process control (MSPC) methodology was investigated for in-line monitoring of alcohol precipitation. The effectiveness of the proposed approach was evaluated through an experimental campaign. Six batches were run under normal operating conditions to study batch-to-batch variation or batch reproducibility and establish MSPC control limits, while artificial process variations were purposefully introduced into the four test batches to assess the capability of the model for real-time fault detection. Several MSPC tools were compared and assessed. NIRS, in conjunction with MSPC, has proven to be a feasible process analytical technology (PAT) tool for monitoring batch evolution and potentially facilitating model-based advanced process control of the alcohol precipitation during the manufacture of Chinese herbal injections.
Lytic polysaccharide monooxygenases (LPMOs) are key enzymes in both the natural carbon cycle and the biorefinery industry. Understanding the molecular basis of LPMOs acting on polysaccharide ...substrates is helpful for improving industrial cellulase cocktails. Here we analyzed the sequences, structures, and substrate binding modes of LPMOs to uncover the factors that influence substrate specificity and regioselectivity. Our results showed that the different compositions of a motif located on L2 affect the electrostatic potentials of substrate binding surfaces, which in turn affect substrate specificities of AA10 LPMOs. A conserved Asn at a distance of 7 Å from the active center Cu might, together with the conserved Ser immediately before the second catalytic His, determine the localization of LPMOs on substrate, and thus contribute to C4-oxidizing regioselectivity. The findings in this work provide an insight into the molecular basis of substrate specificity and regioselectivity of LPMOs.
According to the classification of the quark model, the hadrons going beyond three-quark baryon and quark-antiquark meson pictures are called exotic hadrons. Many new hadrons have been observed since ...2003, some of which exhibit exotic behaviors. There are a lot of excellent review articles on exotic hadrons available so far; the present article tries to focus on the recent experimental and theoretical progress on the exotic states from the perspective of the quark model. Although lattice quantum chromodynamics may give the final answer of the problem, the phenomenological models are still powerful tools to explore the exotic states and to provide insight on the phenomenology of hadrons. The spatial and color structures of multiquark states and the channel coupling calculation are emphasized through reviewing some bound states, molecular and color structure resonances. Finally, the unquench effects of some exotic states are reviewed. With the accumulation of experimental data on multiquark states and inspiration of underlying theory developments, more reasonable phenomenological models incorporating multi-body interactions and high Fock components to unify the description of normal hadrons and exotic hadrons are expectable.
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