Search

Abstract An increasing number of experimental measurements from the BESIII, Belle, and Belle-II collaborations encourage investigations into charmed baryon two-body decay processes. By including contributions from the penguin diagrams that are ignored in previous studies, we perform a global analysis with SU(3) flavor symmetry. Assuming all form factors are real, we achieve a remarkable minimal $$\chi ^{2}/d.o.f = 0.788$$ χ 2 / d . o . f = 0.788 and find that the contribution of the amplitude proportional to $$V_{cb}^*V_{ub}$$ V cb ∗ V ub is of the order $$\sim 0.01$$ ∼ 0.01 , comparable with the contribution of the tree-level diagram. Additionally, by using the KPW theorem to reduce the number of amplitudes from 13 to 7 in the leading contribution, it becomes possible to consider the complex form factor case for the leading IRA amplitude in the global analysis. However, the analysis of complex form factors significantly conflicts with the experimental data $$Br(\Xi _c^0\rightarrow \Xi ^-\pi ^+)$$ B r ( Ξ c 0 → Ξ - π + ) , and by excluding this data, $$\chi ^2/d.o.f$$ χ 2 / d . o . f is reduced from 5.95 to 1.19. Although the analysis of complex form factors shows a significant central value of the penguin diagram contribution, the large errors from the corresponding form factors make it a challenge to precisely determine its true contribution. Consequently, the direct CP violation in decay processes is predicted to be approximately zero. With more data in future experiments, the penguin diagram contribution with the amplitude proportional to $$V_{cb}^*V_{ub}$$ V cb ∗ V ub will be precisely determined, allowing for a more accurate prediction of CP violation. Our analysis necessitates further theoretical investigations and experimental measurements in the future.

Carbon quantum dots (CQDs) with good water solubility and fluorescence properties were successfully synthesized from Chenopodium quinoa Willd. straw, a biomass by-product, by a one-step carbonization method. Structural characterization of the fabricated carbon quantum dots by Fourier transform infrared spectroscopy (FT-IR) demonstrated the presence of a large number of functional groups on the surface of the carbon quantum dots, which gives them good water solubility. The synthesized carbon quantum dots were characterized optically by ultraviolet-visible absorption spectroscopy (UV-Vis), photoluminescence spectroscopy (PL), and other analytical tools. Results indicate the addition of alkali metal ions gave a different degree of promotion of fluorescence intensity (Li+＞Cs+＞K+＞Na+＞Rb+), and according to this feature carbon quantum dots can be used as a new means of alkali metal ion detection.

Abstract We studied the decays of Heavy baryon into a pseudoscalar meson and a dark baryon in the recently developed B-Mesogenesis scenario, where the two types of effective Lagrangians proposed by the scenario are both considered. The decay amplitudes of $$\Lambda _b^0$$ Λ b 0 are calculated by light-cone sum rules using its light-cone distribution amplitudes. The decay amplitudes of $$\Xi _b^{0,\pm }$$ Ξ b 0 , ± are related with those of $$\Lambda _b^0$$ Λ b 0 through a flavor SU(3) analysis. The uncertainties of threshold parameter and the Borel parameter are both considered in the numerical calculation. The values of effective coupling constants in the B-Mesogenesis are taken as their upper limits that obtained from our previous study on the inclusive decay. The upper limits of the decay branching fractions are presented as functions of the dark baryon mass.

Abstract We study the masses and production modes of pentaquark with the quark constituent $$c\bar{q}qqq$$ c q ¯ q q q , by the tridiquark-diquark model and systematical light flavor quark symmetry SU(3) analysis. The mass spectrums show that the S-wave singly charm pentaquark $$c{\bar{n}}nnn,~c{\bar{s}}ssn,~c{\bar{n}}ssn$$ c n ¯ n n n , c s ¯ s s n , c n ¯ s s n and $$c{\bar{n}}snn$$ c n ¯ s n n $$(n=u,d)$$ ( n = u , d ) are above their strong decay thresholds, while $$c{\bar{s}} nnn$$ c s ¯ n n n and $$c\bar{s} snn$$ c s ¯ s n n with parity $$\frac{1}{2}^-$$ 1 2 - are below their strong decay thresholds, which imply the possibility of stable states. Furthermore, we discuss the production of the concerned 15 states from B meson, the analysis within SU(3) symmetry yields the golden channels of production process, $${\overline{B}}^0_s\rightarrow F_{\bar{s}udd}^{+} {\overline{p}},\ B^-\rightarrow F_{\bar{u}dds}^{-} {\overline{\Lambda }}^0$$ B ¯ s 0 → F s ¯ u d d + p ¯ , B - → F u ¯ d d s - Λ ¯ 0 , which expected to be work worthily in b-factory.

Abstract Using the recently developed B-Mesogenesis scenario, we studied the semi-inclusive decays of B meson into a dark anti-baryon $$\psi $$ ψ plus any possible states X containing u/c and d/s quarks with unit baryon number. The two types of effective Lagrangians proposed by the scenario are both considered in the study. The semi-inclusive decay branching fractions of $$B\rightarrow X \psi $$ B → X ψ are calculated by the method of heavy quark expansion, where the non-perturbative contributions from the matrix elements of dimension-5 operators are included. We obtained the branching fractions as functions of the dark anti-baryon mass. Using the experimental upper limits of the branching fractions, we presented the constraints of the coupling constants in the B-Mesogenesis scenario.

Abstract In the paper, we study the production of pentaquark $$\bar{c}q qqq$$ c ¯ q q q q from singly bottom baryon. The tensor representations of pentaquark $$\bar{c}q qqq$$ c ¯ q q q q are completed at first. Under the light quark symmetry analysis, we decompose the singly charmed pentaquarks into 6, 15 and $$15'$$ 15 ′ multiple states, and deduce the representations of these states. Then we construct the production Hamiltonian of the multiple states in proper order. For completeness, we systematically study the production channels of pentaquark states, including the possible production amplitudes and decay relations between different channels, concurrently, the widths of selected channels are worked out with the effective Lagrangian approach. Ultimately, we expect that the chosen channels will be fairly valuable supports for future search experiments.

Abstract After the experimental observation of charged and neutral $$Z_c(3900)$$ Z c ( 3900 ) , it is of prime importance to pursue searches for additional production modes of these exotic states. In this work, we investigate the possibility to study the $$Z_c(3900)$$ Z c ( 3900 ) through weak decays of b-baryons at the LHCb. Decay amplitudes for various processes have been parametrized in terms of the SU(3) irreducible nonperturbative amplitudes. A number of relations for the partial decay widths are deduced from these results. The decay widths of $$\Lambda _b^0\rightarrow \Lambda ^0 Z_c^0(3900)$$ Λ b 0 → Λ 0 Z c 0 ( 3900 ) , $$\Xi _b^- \rightarrow \Sigma ^- Z_{c}^0(3900)$$ Ξ b - → Σ - Z c 0 ( 3900 ) and $$\Xi _b^0 \rightarrow \Lambda ^0 Z_{c}^0(3900)$$ Ξ b 0 → Λ 0 Z c 0 ( 3900 ) have also been calculated from which some relevant partial decay widths of b-baryons could be estimated. The results presented in this paper can be tested experimentally at hadron colliders in the future.

Abstract Background Heterosis is widely used in many crops and is important for global food safety, and maize is one of the most successful crops to take advantage of heterosis. Gene expression patterns control the development of the maize ear, but the mechanisms by which heterosis affects transcriptional-level control are not fully understood. Results In this study, we sampled ear inflorescence meristems (IMs) from the single-segment substitution maize (Zea mays) line lx9801 hlEW2b , which contains the heterotic locus hlEW2b associated with ear width, as well as the receptor parent lx9801, the test parent Zheng58, and their corresponding hybrids Zheng58 × lx9801 hlEW2b (HY) and Zheng58 × lx9801 (CK). After RNA sequencing and transcriptomic analysis, 2531 unique differentially expressed genes (DEGs) were identified between the two hybrids (HY vs. CK). Our results showed that approximately 64% and 48% of DEGs exhibited additive expression in HY and CK, whereas the other genes displayed a non-additive expression pattern. The DEGs were significantly enriched in GO functional categories of multiple metabolic processes, plant organ morphogenesis, and hormone regulation. These essential processes are potentially associated with heterosis performance during the maize ear developmental stage. In particular, 125 and 100 DEGs from hybrids with allele-specific expression (ASE) were specifically identified in HY and CK, respectively. Comparison between the two hybrids suggested that ASE genes were involved in different development-related processes that may lead to the hybrid vigor phenotype during maize ear development. In addition, several critical genes involved in auxin metabolism and IM development were differentially expressed between the hybrids and showed various expression patterns (additive, non-additive, and ASE). Changes in the expression levels of these genes may lead to differences in auxin homeostasis in the IM, affecting the transcription of core genes such as WUS that control IM development. Conclusions Our research suggests that additive, non-additive, and allele-specific expression patterns may fine-tune the expression of crucial DEGs that modulate carbohydrate and protein metabolic processes, nitrogen assimilation, and auxin metabolism to optimal levels, and these transcriptional changes may play important roles in maize ear heterosis. The results provide new information that increases our understanding of the relationship between transcriptional variation and heterosis during maize ear development, which may be helpful for clarifying the genetic and molecular mechanisms of heterosis.

Abstract We study the masses and lifetimes of doubly charmed pentaquark $$P_{cc{\bar{q}}qq}(q=u,d,s)$$ P c c q ¯ q q ( q = u , d , s ) primarily. The operation of masses carried out by the doubly heavy triquark-diquark model, whose results suggests the existence of stable states $$cc{\bar{s}} ud$$ c c s ¯ u d with the parity $$J^P=\frac{1}{2}^-$$ J P = 1 2 - . The roughly calculation about lifetimes show the short magnitudes, $$(4.65^{+0.71}_{-0.55})\times 10^{-13}s $$ ( 4 . 65 - 0.55 + 0.71 ) × 10 - 13 s for the parity $$J^P=\frac{1}{2}^-$$ J P = 1 2 - and $$(0.93^{+0.14}_{-0.11})\times 10^{-12} s $$ ( 0 . 93 - 0.11 + 0.14 ) × 10 - 12 s for $$J^P=\frac{3}{2}^-$$ J P = 3 2 - . Since the pentaquark $$cc{\bar{s}} ud$$ c c s ¯ u d is interpreted as the stable bound states against strong decays, then we will focus on the production and possible decay channels of the pentaquark in the next step, the study would be fairly valuable supports for future experiments. For completeness, we systematically studied the production from $$\Omega _{ccc}$$ Ω ccc and the decay modes in the framework SU(3) flavor symmetry, including the processes of semi-leptonic and two body non-leptonic decays. Synthetically, we make a collection of the golden channels.

Abstract We perform a SU(3) analysis for both semi-leptonic and non-leptonic heavy meson weak decays into a pseudoscalar meson and a fully-light tetraquark in 10 or 27 representation. A reduction of the SU(3) representation tensor for the fully-light tetraquarks is produced and all the flavor components for each representation tensor are listed. The decay channels we analysis include $$B/D \rightarrow U/T~P~l\nu $$ B / D → U / T P l ν , $$B/D \rightarrow U/T~P $$ B / D → U / T P and $$B_c \rightarrow U/T~P/D$$ B c → U / T P / D , with U/T represents a fully-light tetraquark in 10 or 27 representation and P is a pseudoscalar meson. Finally, among these results we list all the golden decay channels which are expected to have more possibilities to be observed in experiments.

Abstract We study masses, lifetimes and weak decays of the triply heavy tetraquarks $${b{\bar{c}}}{b{\bar{q}}}$$ bc¯bq¯ . The masses of tetraquark are explored under two different models. Further more, our calculations show a possibility of existence for the stable triply heavy tetraquark $$b{\bar{c}} b{\bar{q}} $$ bc¯bq¯ with $$J^P=1^+$$ JP=1+ which should be verified in experiment. Following the heavy quark expanding(HQE), the lifetimes of tetraquarks $${b{\bar{c}}}{b{\bar{q}}}$$ bc¯bq¯ can be expressed as the summation of different dimension operators. Particularly, we obtain the lifetimes of $${b{\bar{c}}}{b{\bar{q}}}$$ bc¯bq¯ at the next-to-leading order(NLO) given as $$\tau (T^{\{bb\}}_{\{{\bar{c}}{\bar{q}}\}})=0.70\times 10^{-12}s$$ τ(T{c¯q¯}{bb})=0.70×10-12s . Besides, we construct the weak decays Hamiltonian of $${b{\bar{c}}}{b{\bar{q}}}$$ bc¯bq¯ in hadronic level under the SU(3) flavor symmetry. The discussion of the Hamiltonian can deduce the decay amplitudes and width relations of the tetraquarks. Following the choosing rules, we collect some golden channels for the mesonic decays of tetraquarks, which will be helpful to search for triply heavy tetraquarks $${b{\bar{c}}}{b{\bar{q}}}$$ bc¯bq¯ in future experiments.

Abstract We study the lifetime and weak decays of the full-heavy S-wave $$0^+$$ 0+ tetraquark $$T^{\{bb\}}_{\{{\bar{c}}{\bar{c}}\}}$$ T{c¯c¯}{bb} . Using the operator product expansion rooted in heavy quark expansion, we find a rather short lifetime, at the order $$(0.1-0.3)\times 10^{-12}s$$ (0.1-0.3)×10-12s depending on the inputs. With the flavor SU(3) symmetry, we then construct the effective Hamiltonian at the hadron level, and derive relations between decay widths of different channels. According to the electro-weak effective operators, we classify different decay modes, and make a collection of the golden channels, such as $$T_{\{{\bar{c}} {\bar{c}}\}}^{\{bb\}}\rightarrow B^- K^0 B_c^-$$ T{c¯c¯}{bb}→B-K0Bc- for the charm quark decay and $$T_{\{{\bar{c}} {\bar{c}}\}}^{\{bb\}}\rightarrow B^-D^-$$ T{c¯c¯}{bb}→B-D- for the bottom quark decay. Our results for the lifetime and golden channels are helpful to search for the fully-heavy tetraquark in future experiments.

Abstract We analyze the weak decay of doubly-heavy baryon decays into anti-triplets $$\Lambda _Q$$ ΛQ with light-cone sum rules. To calculate the decay form factors, both bottom and charmed anti-triplets $$\Lambda _b$$ Λb and $$\Lambda _c$$ Λc are described by the same set of leading twist light-cone distribution amplitudes. With the obtained form factors, we perform a phenomenology study on the corresponding semi-leptonic decays. The decay widths are calculated and the branching ratios given in this work are expected to be tested by future experimental data, which will help us to understand the underlying dynamics in doubly-heavy baryon decays.

Abstract The exotic state X(5568) which was observed by D0 Collaboration is very likely to be a tetraquark state with four different valence quark flavors, though the existence was not confirmed by other collaborations. The possibility of such state still generates lots of interests in theory. In the paper, we will study the properties of the state under the SU(3) flavor symmetry. The four quark states with a heavy bottom quark and three light quarks(anti-quark) can form $${\bar{3}}$$ 3¯ , 6 and $${\overline{15}}$$ 15¯ representations. The weak decays can be dominant and should be discussed carefully while these states are stable against the strong and electromagnetic interactions. Therefor we will study the multi-body semileptonic and nonleptonic weak decays systematically. With the help of SU(3) flavor symmetry, we can give the Hamiltonian in the hadronic level, then obtain the parameterized irreducible amplitudes and the relations of different channels. At the end of the article, we collect some Cabibbo allowed two-body and three-body weak decay channels which can be used to reconstruct $$X_{b6}$$ Xb6 states at the branching fraction up to be $$10^{-5}$$ 10-5 .

Abstract We study the weak decays of exotic tetraquark states $${b\bar{c}}{q\bar{q}}$$ bc¯qq¯ with two heavy quarks. Under the SU(3) symmetry for light quarks, these tetraquarks can be classified into an octet plus a singlet: $$3\bigotimes \bar{3}=1\bigoplus 8$$ 3⨂3¯=1⨁8 . We will concentrate on the octet tetraquarks with $$J^{P}=0^{+}$$ JP=0+ , and study their weak decays, both semileptonic and nonleptonic. Hadron-level effective Hamiltonian is constructed according to the irreducible representations of the SU(3) group. Expanding the Hamiltonian, we obtain the decay amplitudes parameterized in terms of a few irreducible quantities. Based on these amplitudes, relations for decay widths are derived, which can be tested in future. We also give a list of golden channels that can be used to look for these states at various colliders.

Objective To analyze the forensic characteristics of 24 psychiatric patients who died of long-term use of psychotropic drugs. Methods Cases of sudden death of psychiatric patients from 2011 to 2016 were collected. The forensic characteristics of these sudden deaths were retrospectively analyzed by systematic investigation plus results of autopsy and toxics （drugs）. Results Among the 24 psychiatric patients who died of long-term use of psychotropic substances, the ratio of male to female was 1.7∶1, and the average age was （59.0±8.8） years. Fifteen patients had clear disease durations （14.4±8.2） years, and other the nine were known to have disease durations of over 3 years. The death time of 62.5% of patients was the daytime in working days, and 91.7% of the patients died at home. Most patients complained different degrees of physical discomfort before death. Patients with schizophrenia （20 cases） were the most common, followed by depression （4 cases）. All patients had the history of taking psychotropic drugs, with clozapine and chlorpromazine being the mostly detected ones. The causes of death were mainly circulatory diseases （15 cases）, with the most common being myocarditis （11 cases） followed by pneumonia （4 cases）. Conclusion Critical attention should be paid to the risk of antipsychotics-induced sudden unexpected deaths for psychiatric patients, particularly for those with schizophrenia.

Abstract The newly-discovered $$\Xi _{cc}^{++}$$ Ξcc++ decays into the $$ \Lambda _{c}^+ K^-\pi ^+\pi ^+$$ Λc+K-π+π+ , but the experimental data has indicated that this decay is not saturated by any two-body intermediate state. In this work, we analyze the multi-body weak decays of doubly heavy baryons $$\Xi _{cc}$$ Ξcc , $$\Omega _{cc}$$ Ωcc , $$\Xi _{bc}$$ Ξbc , $$\Omega _{bc}$$ Ωbc , $$\Xi _{bb}$$ Ξbb and $$\Omega _{bb}$$ Ωbb , in particular the three-body nonleptonic decays and four-body semileptonic decays. We classify various decay modes according to the quark-level transitions and present an estimate of the typical branching fractions for a few golden decay channels. Decay amplitudes are then parametrized in terms of a few SU(3) irreducible amplitudes. With these amplitudes, we find a number of relations for decay widths, which can be examined in future.

This paper aimed to develop a high-performance liquid chromatography (HPLC) method that can simultaneously detect ten biogenic amines (BAs) in commercially available soybean paste and to determine the contents of BAs in these products. Heptylamine (Hep) was used as the internal standard reagent and benzoyl chloride as the sample derivatization reagent; Inertsil ODS-3 chromatographic column was set as the stationary phase while the acetonitrile and 5 mmol/L ammonium acetate solution as the mobile phases; the samples were treated with gradient elution and detected at 254 nm (UV). Perchloric acid solution (0.4 mol/L) was employed as the sample extraction solvent to determine the contents of ten BAs in soybean paste products. All BAs were separated within 20 min. The methodological validation suggested good linearity, whereas the linear correlation coefficient of all standards was greater than 0.99 with the linear range of 0.1–80 μg/g, detection limits of 0.01–0.03 μg/g, and quantitation limits of 0.03–0.10 μg/g. For 17 commercially available soybean paste products involved in our study, different samples were distinguished from each other not only by the dramatic differences in the contents of BAs but also by the variance in BA types. Of these BAs, tyramine (Tyr) and agmatine (Agm) were found to be the highest contents in soybean paste products; the contents of histamine (His), 2-phenylethylamine (Phe), serotonin (Ser), spermidine (Spd), and putrescine (Put) were lower, followed by cadaverine (Cad), tryptamine (Try), and spermine (Spm). This method proved to be highly sensitive and effective in determining the contents of BAs in soybean paste products; there was a dramatic difference in the contents of ten BAs among different soybean paste products.

Productivity rise can be realized at high-speed welding, but in a practice, the constraints emanate from the tolerance welding speed limit beyond which generate humping defects and the likes. These defects are undesirable in welding as they undermined the weld bead integrity and decrease productivity. In this study, an investigation on a lap joint welding using a hybrid Laser-GMAW (L-GMAW) welding process on a carbon steel sheet was undertaken to examine the mechanisms involved in the arc behavior, the droplet transfer, and the weld pool flow dynamics in a hump defect formation at high-speed welding. A variation of the process parameters in the hybrid welding system such as the wire feed speed (WFS), the traveling speed (TS) and the oscillation of the laser beam were used as input signals. A high-speed video camera was used with different viewing positions to capture the sequence of events during the hybrid welding process. The high-speed images of the arc behavior, the weld pool flow pattern with the use of tracer particles in arriving at the root mechanisms were acquired. Based on the experimental resultant, the occurrence mechanisms of the weld defects were proposed. In this study, the key factors in the humping defect formation are the two dominant lateral flows toward the top and bottom sheets, the collision between the weld pool back- and rear-flow and the interruption of the weld pool flow channel. Also, the generation of copious spatter due to the two lateral flows and the swollen buildup towards the hump closure were responsible for the next hump initiation formation. The beam oscillation applied to wet the weld toe angle to delay the outset of the humping defect occurrence was insignificant at higher travel speed. Furthermore, the force of gravity and surface tension were the key forces in this study. Keywords: Hybrid L-GMAW, Lap joint, Arc behavior, Droplet transfer, Hump formation, High travel speed

ABSTRACT Since 2009, catfish farming in the southeastern United States has been severely impacted by a highly virulent and clonal population of Aeromonas hydrophila causing motile Aeromonas septicemia (MAS) in catfish. The possible origin of this newly emerged highly virulent A. hydrophila strain is unknown. In this study, we show using whole-genome sequencing and comparative genomics that A. hydrophila isolates from diseased grass carp in China and catfish in the United States have highly similar genomes. Our phylogenomic analyses suggest that U.S. catfish isolates emerged from A. hydrophila populations of Asian origin. Furthermore, we identified an A. hydrophila strain isolated in 2004 from a diseased catfish in Mississippi, prior to the onset of the major epidemic outbreaks in Alabama starting in 2009, with genomic characteristics that are intermediate between those of the Asian and Alabama fish isolates. Investigation of A. hydrophila strain virulence demonstrated that the isolate from the U.S. catfish epidemic is significantly more virulent to both channel catfish and grass carp than is the Chinese carp isolate. This study implicates the importation of fish or fishery products into the United States as the source of highly virulent A. hydrophila that has caused severe epidemic outbreaks in United States-farmed catfish and further demonstrates the potential for invasive animal species to disseminate bacterial pathogens worldwide. IMPORTANCE Catfish aquaculture farming in the southeastern United States has been severely affected by the emergence of virulent Aeromonas hydrophila responsible for epidemic disease outbreaks, resulting in the death of over 10 million pounds of catfish. Because the origin of this newly emerged A. hydrophila strain is unknown, this study used a comparative genomics approach to conduct a phylogenomic analysis of A. hydrophila isolates obtained from the United States and Asia. Our results suggest that the virulent isolates from United States-farmed catfish have a recent common ancestor with A. hydrophila isolates from diseased Asian carp. We have also observed that an Asian carp isolate, like recent U.S. catfish isolates, is virulent in catfish. The results from this study suggest that the highly virulent U.S. epidemic isolates emerged from an Asian source and provide another example of the threat that invasive species pose in the dissemination of bacterial pathogens.