Lately, the LHCb Collaboration reported the discovery of two new states in the
B
+
→
D
+
D
-
K
+
decay, i.e.,
X
0
(
2866
)
and
X
1
(
2904
)
. In the present work, we study whether these states can be ...understood as
D
¯
∗
K
∗
molecules from the perspective of their two-body strong decays into
D
-
K
+
via triangle diagrams and three-body decays into
D
¯
∗
K
π
. The coupling of the two states to
D
¯
∗
K
∗
are determined from the Weinberg compositeness condition, while the other relevant couplings are well known. The obtained strong decay width for the
X
0
(
2866
)
state, in marginal agreement with the experimental value within the uncertainty of the model, hints at a large
D
¯
∗
K
∗
component in its wave function. On the other hand, the strong decay width for the
X
1
(
2904
)
state, much smaller than its experimental counterpart, effectively rules out its assignment as a
D
¯
∗
K
∗
molecule.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Inspired by the recent discovery of a doubly charmed tetraquark state Tcc+ by the LHCb Collaboration, we employ the effective Lagrangian approach to investigate the decay width of Tcc+→D+D0π0/D0D0π+ ...and Tcc+→D0D+γ with the assumption that Tcc+ is an isoscalar DD⁎ molecule. We show that both the Tcc→DDπ and Tcc→DDγ modes contribute to the decay width of Tcc, with the former being dominant. The resulting total decay width of about Γ=63 keV is smaller than the experimental decay width obtained from the Breit-Wigner fit of the LHCb data, Γ=410±165±43−38+18 keV, while close to the number obtained from the alternative unitary analysis, Γ=48±2−14+0 keV, which supports the molecular nature of Tcc.
Recently, the Belle collaboration measured the ratios of the branching fractions of the newly observed
Ω
(
2012
)
excited state. They did not observe significant signals for the
Ω
(
2012
)
→
K
¯
Ξ
∗
...(
1530
)
→
K
¯
π
Ξ
decay, and reported an upper limit for the ratio of the three body decay to the two body decay mode of
Ω
(
2012
)
→
K
¯
Ξ
. In this work, we revisit the newly observed
Ω
(
2012
)
from the molecular perspective where this resonance appears to be a dynamically generated state with spin-parity
3
/
2
-
from the coupled channels interactions of the
K
¯
Ξ
∗
(
1530
)
and
η
Ω
in
s
-wave and
K
¯
Ξ
in
d
-wave. With the model parameters for the
d
-wave interaction, we show that the ratio of these decay fractions reported recently by the Belle collaboration can be easily accommodated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Because of the discovery of the hidden-charm pentaquark Pc states by the LHCb Collaboration, the interests in the candidates of hidden-bottom pentaquark Pb states are increasing. They are anticipated ...to exist as the analogs of the Pc states in the bottom sector and predicted by many models. We give an exploration of searching for a typical Pb in the γ p → Υ p reaction, which shows a promising potential to observe it at an electron-ion collider. The possibility of searching for Pb in open-bottom channels is also briefly discussed. Meanwhile, the t -channel nonresonant contribution, which in fact covers several interesting topics at low energies, is systematically investigated.
A resonance-like structure as narrow as 10 MeV is observed in the K−p invariant mass distributions in Λc+→pK−π+ at Belle. Based on the large data sample of about 1.5 million events and the small bin ...width of just 1 MeV for the K−p invariant mass spectrum, the narrow peak is found precisely lying at the Λη threshold. While lacking evidence for a quark model state with such a narrow width at this mass region, we find that this narrow structure can be naturally identified as a threshold cusp but enhanced by the nearby triangle singularity via the Λ−a0(980)+ or η−Σ(1660)+ rescatterings.
Heavy-quark symmetry as applied to heavy hadron systems implies that their interactions are independent of their heavy-quark spin (heavy-quark spin symmetry) and heavy flavor contents (heavy flavor ...symmetry). In the molecular hypothesis the X(3872) resonance is a 1++ D*D¯ bound state. If this is the case, the application of heavy-quark symmetry to a molecular X(3872) suggests the existence of a series of partner states, the most obvious of which is a possible 2++ D*D¯* bound state for which the two-body potential is identical to that of the 1++ D*D¯ system, the reason being that these two heavy hadron-antihadron states have identical light-spin content. As already discussed in the literature, this leads to the prediction of a partner state at 4012 MeV, at least in the absence of other dynamical effects which might affect the location of this molecule. However the prediction of further heavy-quark symmetry partners cannot be made solely on the basis of symmetry and requires additional information. We propose to use the one-boson-exchange model to fill this gap, in which case we will be able to predict or discard the existence of other partner states. Besides the isoscalar 2++ D*D¯* bound state, we correctly reproduce the location and quantum numbers of the isovector hidden-bottom Zb(10610) and Zb(10650) molecular candidates. We also predict the hidden-bottom 1++ B*B¯* and 2++ B*B¯* partners of the X(3872), in agreement with previous theoretical speculations, plus a series of other states. The isoscalar, doubly charmed 1+ DD* and D*D* molecules, and their doubly bottomed counterparts are likely to bind, providing a few instances of explicitly exotic systems.
Abstract
Epoxy resin has been widely applied in coating preparation, due to its excellent properties. The anti‐corrosion performance improvement of epoxy‐based coatings has attracted much attention. ...The synergistic effect of the barrier function of two‐dimensional fillers and the slow release of inhibiter has been proven to be an effective way to improve the anti‐corrosion of coatings. In this work, the phytic acid (PA) intercalated hydrotalcite (HT) was fabricated by a one‐pot method. First, HT was synthesized by magnesium nitrate hexahydrate (Mg(NO
3
)
2
·6H
2
O) and aluminum nitrate nonahydrate (Al(NO
3
)
3
·9H
2
O) in the water solution. Subsequently, PA was added to the dispersion to obtain PA intercalated HT fillers (PA‐HT). The obtained PA‐HT fillers were incorporated into the epoxy resin (EP) to prepare the anti‐corrosion coating (PA‐HT/EP). The prepared PA‐HT/EP coating exhibits excellent anti‐corrosion properties at 1 wt% filler loading that the impedance modulus maintains above 10
9
Ω cm
2
after 30 days of soaking in 3.5 wt% NaCl solution. Moreover, the anti‐corrosion mechanism of the synergy of the physical barrier of two‐dimensional fillers and the release slow of inhibitors was thoroughly discussed, particularly the formation and anti‐corrosion mechanism of the passivation protection film constituted by PA.
The LHCb collaboration has recently observed three pentaquark peaks, the Pc(4312), Pc(4440) and Pc(4457). They are very close to a pair of heavy baryon-meson thresholds, with the Pc(4312) located 8.9 ...MeV below the DΣc threshold, and the Pc(4440) and Pc(4457) located 21.8 and 4.8 MeV below the D∗Σc one. The spin-parities of these three states have not been measured yet. In this work we assume that the Pc(4312) is a JP = 1/2− ¯DΣc bound state, while the Pc(4440) and Pc(4457) are ¯D∗Σc bound states of unknown spin-parity, where we notice that the consistent description of the three pentaquarks in the one-boson-exchange model can indeed determine the spin and parities of the later, i.e., of the two ¯ D∗Σc molecular candidates. For this determination we revisit first the one-boson-exchange model, which in its original formulation contains a short-range deltalike contribution in the spin-spin component of the potential. We argue that it is better to remove these deltalike contributions because, in this way, the one-boson-exchange potential will comply with the naïve expectation that the form factors should not have a significant impact in the long-range part of the potential (in particular the one-pion-exchange part). Once this is done, we find that it is possible to consistently describe the three pentaquarks, to the point that the Pc(4440) and Pc(4457) can be predicted from the Pc(4312) within a couple of MeV with respect to their experimental location. In addition the so-constructed one-boson-exchange model predicts the preferred quantum numbers of the Pc(4440) and Pc(4457) molecular pentaquarks to be 3/2− and 1/2−, respectively.
Bacteriophages, simply phages, have long been used as a potential alternative to antibiotics for livestock due to their ability to specifically kill enterotoxigenic Escherichia coli (ETEC), which is ...a major cause of diarrhea in piglets. However, the control of ETEC infection by phages within intestinal epithelial cells, and their relationship with host immune responses, remain poorly understood. In this study, we evaluated the effect of phage EK99P-1 against ETEC K99-infected porcine intestinal epithelial cell line (IPEC-J2). Phage EK99P-1 prevented ETEC K99-induced barrier disruption by attenuating the increased permeability mediated by the loss of tight junction proteins such as zonula occludens-1 (ZO-1), occludin, and claudin-3. ETEC K99-induced inflammatory responses, such as interleukin (IL)-8 secretion, were decreased by treatment with phage EK99P-1. We used a IPEC-J2/peripheral blood mononuclear cell (PBMC) transwell co-culture system to investigate whether the modulation of barrier disruption and chemokine secretion by phage EK99P-1 in ETEC K99-infected IPEC-J2 would influence immune cells at the site of basolateral. The results showed that phage EK99P-1 reduced the mRNA expression of ETEC K99-induced pro-inflammatory cytokines, IL-1β and IL-8, from PBMC collected on the basolateral side. Together, these results suggest that phage EK99P-1 prevented ETEC K99-induced barrier dysfunction in IPEC-J2 and alleviated inflammation caused by ETEC K99 infection. Reinforcement of the intestinal barrier, such as regulation of permeability and cytokines, by phage EK99P-1 also modulates the immune cell inflammatory response.
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