[Exploration and contemplation of homogenized education of specialists in pulmonary and critical care medicine at member hospitals of a hospital consortium]

Talent construction is the cornerstone to the establishment of a high-quality, homogeneous healthcare system in a healthcare consortium. Pulmonary and critical care medicine (PCCM) as the first pilot specialty, the standardized training of PCCM specialists has started and achieved remarkable results. The consortium member hospitals' physician specialist education is an important complement to PCCM training. The establishment of the consortium provides a new form of the education of physicians in PCCM, with the advantages of high quality teaching, wide coverage of staff and throughout the career development process. This article summarized the current status of physician specialty education in the member hospitals of the consortium, and further proposes the goal of homogenized specialty education for physicians in the member hospitals. And it analyzed in depth the problems that existed in the practice of training for hospital consortium member hospitals specialists, such as non-uniform level of instruction, non-systematic content of training, limited sources of teaching cases, and lack of teaching materials and equipment. For the medical consortium member hospital physician specialty education of in-depth thinking, we put forward the corresponding countermeasures. The aim of this study is to explore the homogenization of the specialty education system of pulmonary and critical care medicine in the member hospitals, in order to comprehensively improve the medical level of respiratory specialists in the member hospitals of the medical consortium.

[Clinical characteristics and prognosis analysis of pulmonary sarcomatoid carcinoma]

Objective: To summarize the clinical characteristics, treatment, and outcomes of patients with pulmonary sarcomatoid carcinoma (PSC) in order to improve clinicians' understanding of this disease. Methods: The clinical data of patients diagnosed with PSC in our hospital from January 1, 2015 to November 30, 2023 were retrospectively analyzed. According to whether radical resection was performed, the patients were divided into resectable group and unresectable group. The characteristics and treatments of PSC in different groups were compared. The survival curves were drawn by Kaplan-Meier method to compare the prognosis of different groups of patients. Results: A total of 43 PSC patients were included, including 32 males, with an average age of (62.79±9.59) years, and 31 smokers. Peripheral-type tumors were more common, with imaging showing predominantly solid soft tissue masses, and the maximum diameter of the tumor was more than 5 cm in 14 patients. Among the 23 patients who underwent NGS gene testing, the KRAS mutation rate was 43.5%, the TP53 mutation rate was 30.4%, and the MET mutation rate was 8.7%, all of which were MET-14 exon skipping mutations. PD-L1 expression was detected in 13 patients, 10 of whom showed high expression. The median overall survival (mOS) of the 43 patients with PSC was 24.6 months (13.0-52.7 months). Among them, 22 patients underwent radical lobectomy plus mediastinal lymph node dissection, 13 patients had postoperative recurrence, and 7 patients died during follow-up. The median disease-free survival (mDFS) was 12.3 months, the mOS was not achieved and the 1-year OS rate was 77.3 %. Twenty-one patients had unresectable locally advanced or advanced stage, and 15 patients died. The mDFS was 2.5 months, the mOS was 6.2 months, and the 1-year OS rate was 42.9 %. Seventeen patients received immunotherapy, and 1 patient received targeted therapy with the MET inhibitor glumetinib. Conclusions: PSC has a higher incidence in the elderly, smokers, and males, is highly malignant and has a poor prognosis. Based on its molecular biological characteristics, PD-L1 expression and tumor molecular detection can be performed to guide treatment options.

[The association between baseline TPOAb and/or TgAb positivity and thyroid immune-related adverse events in patients with malignancies following treatment with immune checkpoint inhibitors]

Objective: To investigate the association between positive anti-thyroid peroxidase antibody (TPOAb) and/or anti-thyroglobulin antibody (TgAb) and the occurrence of thyroid immune-related adverse events (irAEs) in patients with malignant tumors who treated with immune checkpoint inhibitors (ICIs). Methods: A case-control study. A total of 116 patients with malignant tumor who received ICIs treatment and underwent thyroid function evaluation at Peking Union Medical College Hospital from January 2017 to April 2023 were enrolled retrospectively, including 77 males and 39 females, with a median age of (M(Q1, Q3)) 63.0 (55.0, 70.0) years. The patients were divided into the euthyroid group (n=58) and the thyroid irAEs group (n=58) according to whether thyroid irAEs occurred after ICIs treatment. The clinical characteristics and baseline anti-thyroid antibodies associated with the occurrence of thyroid irAEs after ICIs treatment in patients with malignant tumors were evaluated. Variables with statistical significance in univariate analysis were included in multivariate logistic regression model to analyze the risk factors for thyroid irAEs in patients with malignant tumors who received ICIs treatment. Results: In irAEs group, therewore 4 (3.4%) cases of clinical thyrotoxicosis, 23(19.8%) cases of subclinical thyrotoxicosis, 23 (19.8%) cases of clinical hypothyroidism, and 8(6.9%) cases of subclinical hypothyroidism. The positive rate of anti-thyroid antibodies at baseline in the thyrioid irAEs group was higher than that in the euthyroid group［16/58（27.6%）vs 3/58（5.2%），P=0.001］. After at least one course of ICIs treatment, the incidence of thyroid irAEs in patients with positive anti-thyroid antibodies at baseline was 84.2% (16/19), whereas it was 43.3% (42/97) in patients with negative anti-thyroid antibodies(P=0.001). Univariate logistic regression analysis showed that gender (OR=2.812, 95%CI:1.257-6.293), baseline thyroid autoantibodies were positive (OR=6.984, 95%CI: 1.909-25.547), baseline TgAb positivity (OR=8.909, 95%CI: 1.923-41.280), and baseline TPOAb positivity (OR=7.304, 95%CI: 1.555-34.308) were associated with thyroid irAEs (all P<0.05). Multivariate logistic regression analysis indicated that baseline TgAb positivity (OR=7.637, 95%CI: 1.617-36.072) was a risk factor for thyroid irAEs (P=0.01). Conclusions: The incidence of thyroid irAEs is higher in patients who are positive for baseline TPOAb and/or TgAb compared to those who are negative for TPOAb and TgAb. Patients with positive TgAb at baseline are at high risk of developing thyroid irAEs.

[Clinical features and prognostic analysis of checkpoint inhibitor pneumonitis in patients with non-small cell lung cancer]

Objective: To describe the clinical characteristics of patients with non-small cell lung cancer (NSCLC) who developed checkpoint inhibitor pneumonitis (CIP) and to explore potential prognostic factors. Methods: NSCLC patients who were complicated with CIP after immune checkpoint inhibitors (ICIs) therapy in our institute were enrolled in this study from 1 July 2018 to 30 November 2022. Clinical data of NSCLC-CIP patients were collected, including clinical and radiological features and their outcomes. Results: Among the 70 enrolled NSCLC-CIP patients, there were 57 males (81%) and 13 females (19%). The mean age at the diagnosis of CIP was (65.2±6.3) years. There were 46 smokers (66%), 26 patients (37%) with emphysema, 19 patients (27%) with previous interstitial lung disease, and 26 patients (37%) with a history of thoracic radiation. The mean interval from the first application of checkpoint inhibitor to the onset of CIP was (122.7±106.9) days (range: 2-458 days). The main chest CT manifestations were coincided with non-specific interstitial pneumonia (NSIP) pattern and organizing pneumonia (OP) pattern. Most patients had grade 2 (21 cases) or grade 3 (34 cases) CIP. Seventeen patients had been concurrent with other immune-related adverse events such as rash, hepatitis, colitis, and thyroiditis. Half of the enrolled patients (36 patients/51%) had fever, and most patients had elevated C-reactive protein (52 patients/72%) and all patients had elevated erythrocyte sedimentation rate (70 patients/100%). Serum lactate dehydrogenase was elevated in 34 CIP patients. Prednisone≥1 mg·kg-1·d-1 (or equivalent) was the most commonly used initial treatment in CIP patients (50 patients/71.4%). Complications with pulmonary infections (OR=4.44, P=0.03), use of anti-fungal drugs (OR=5.10, P=0.03) or therapeutic dose of sulfamethoxazole (OR=4.86, P=0.04), longer duration of prednisone≥1 mg·kg-1·d-1 (or equivalent) (Z=-2.33, P=0.02) were probable potential risk factors for poor prognosis. Conclusions: Older males with smoking history might be predisposed to develop NSCLC-CIPs after ICIs therapy. NSIP pattern and OP pattern were common chest CT manifestations. Complications with pulmonary infections (especially fungal infection or Pneumocystis jirovecii pneumonia), longer duration, longer duration of high-dose corticosteroids were likely potential risk factors for poor prognosis.

[Clinical analysis of COVID-19 in patients with preexisting interstitial lung abnormalities]

Objective: To describe the clinical characteristics of SARS-CoV-2 infected patients with interstitial lung abnormalities (ILA) during the COVID-19 pandemic. Methods: We respectively enrolled ILA patients who had been regularly followed up in Peking Union Medical College Hospital for more than six months since January 2021. Clinical data of these ILA patients were collected after the outbreak of COVID-19 pandemic (from December 2022 to January 2023), thirty-eight patients with preexisting ILA were enrolled. Among them, there were 34 ILA patients (20 males and 14 females) who were infected with SARS-CoV-2 during this period, with an average age of (64.0±8.8) years old (range: 41-80). There were 12 (35.3%) ILA patients who were suffered from COVID-19(pneumonia group) and others were the non-pneumonia group. The clinical characteristics, including vaccination status, features of COVID-19 and outcomes of the two groups were compared. Results: Regarding the subcategories of ILA, there were 7 cases of subpleural fibrotic ILA, 10 cases of subpleural non-fibrotic ILA, and 17 cases of non-subpleural ILA. Before SARS-CoV-2 infection, the average pulse oxygen saturation at rest was (97.38±0.87)% (range: 96%-99%); average forced vital capacity (FVC) was (97.6±18.1)% predicted (range: 65%-132%); and average diffusion capacity for carbon monoxide (DLCO) was (76.2±16.3)% predicted (range: 53%-108%). Nineteen patients had been vaccinated with 3 doses of SARS-CoV-2 vaccines, and 5 of them developed COVID-19. One patient had received one dose of vaccine and did not develop COVID-19. The other 14 patients had not been vaccinated, and seven of them developed COVID-19. Of the 12 patients with COVID-19, six were diagnosed with severe COVID-19, and the other 6 ILA patients were diagnosed with moderate COVID-19. Among them, 1 patient was complicated by deep vein thrombosis of left lower limb. All 6 patients with severe COVID-19 who were cured after systemic corticosteroids. As for the other six moderate COVID-19 patients, all were cured and/or improved greatly: two were treated with short-term oral corticosteroids, one was prescribed a dose of compound betamethasone, and the other two were not treated with systemic corticosteroids. Conclusion: Patients with ILA were predisposed to develop COVID-19 after infection with SARS-CoV-2, and more than half of them had severe COVID-19.

Steady state engineering of a two-level system by the mixed-state inverse engineering scheme

The mixed-state inverse engineering scheme is a control scheme used for engineering the quantum state of a driven open quantum system from an initial steady state to a final steady state. In this paper, we present an analytical study of this scheme applied to the driven two-level model coupled to a heat reservoir. Typically, when the purity of the quantum state varies, incoherent control techniques are required for mixed-state engineering. However, we show that for both Markovian and non-Markovian dynamics, coherent control protocols can transfer the quantum state into the target state. This simplification comes at a cost, as the evolution of the quantum state must be limited to restricted conditions, resulting in special trajectories in its Hilbert space that connect the initial and target states.

Tests of Light-Lepton Universality in Angular Asymmetries of B^{0}→D^{*-}ℓν Decays

We present the first comprehensive tests of the universality of the light leptons in the angular distributions of semileptonic B^{0}-meson decays to charged spin-1 charmed mesons. We measure five angular-asymmetry observables as functions of the decay recoil that are sensitive to lepton-universality-violating contributions. We use events where one neutral B is fully reconstructed in ϒ(4S)→BB[over ¯] decays in data corresponding to 189  fb^{-1} integrated luminosity from electron-positron collisions collected with the Belle II detector. We find no significant deviation from the standard model expectations.

Precise Measurement of the D_{s}^{+} Lifetime at Belle II

We measure the lifetime of the D_{s}^{+} meson using a data sample of 207  fb^{-1} collected by the Belle II experiment running at the SuperKEKB asymmetric-energy e^{+}e^{-} collider. The lifetime is determined by fitting the decay-time distribution of a sample of 116×10^{3} D_{s}^{+}→ϕπ^{+} decays. Our result is τ_{D_{s}^{+}}=(499.5±1.7±0.9)  fs, where the first uncertainty is statistical and the second is systematic. This result is significantly more precise than previous measurements.

Search for a τ^{+}τ^{-} Resonance in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} Events with the Belle II Experiment

We report the first search for a nonstandard-model resonance decaying into τ pairs in e^{+}e^{-}→μ^{+}μ^{-}τ^{+}τ^{-} events in the 3.6-10  GeV/c^{2} mass range. We use a 62.8  fb^{-1} sample of e^{+}e^{-} collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II experiment at the SuperKEKB collider. The analysis probes three different models predicting a spin-1 particle coupling only to the heavier lepton families, a Higgs-like spin-0 particle that couples preferentially to charged leptons (leptophilic scalar), and an axionlike particle, respectively. We observe no evidence for a signal and set exclusion limits at 90% confidence level on the product of cross section and branching fraction into τ pairs, ranging from 0.7 to 24 fb, and on the couplings of these processes. We obtain world-leading constraints on the couplings for the leptophilic scalar model for masses above 6.5  GeV/c^{2} and for the axionlike particle model over the entire mass range.

Measurement of CP Violation in B^{0}→K_{S}^{0}π^{0} Decays at Belle II

We report a measurement of the CP-violating parameters C and S in B^{0}→K_{S}^{0}π^{0} decays at Belle II using a sample of 387×10^{6}  BB[over ¯] events recorded in e^{+}e^{-} collisions at a center-of-mass energy corresponding to the ϒ(4S) resonance. These parameters are determined by fitting the proper decay-time distribution of a sample of 415 signal events. We obtain C=-0.04_{-0.15}^{+0.14}±0.05 and S=0.75_{-0.23}^{+0.20}±0.04, where the first uncertainties are statistical and the second are systematic.

[Establish a whole-process comprehensive surveillance management mode for immune checkpoint inhibitor pneumonitis]

The application of immune checkpoint inhibitors (ICIs) has shown impressive anti-tumor efficacy across multiple malignant tumors, leading to the prolonged survival period of tumor patients. However, immune-related adverse events should not be ignored. Checkpoint inhibitor pneumonitis (CIP) is a pulmonary adverse event that can occur in malignant tumor patients after receiving ICIs treatment. The incidence of CIP has been reported to range from 2.7% to 20.0% in clinical trials and real-world research. Furthermore, some patients might suffer from serious or fatal CIP, and the prognosis of such patients will be poor. Early detection, diagnosis and treatment may improve the prognosis of these patients. The establishment of a whole-process CIP comprehensive surveillance management mode covering the health care system and patients during ICIs treatment might be helpful to improve the early diagnosis and treatment capacity of CIP, which is a key measure to improve the prognosis of these patients.

Test of Light-Lepton Universality in the Rates of Inclusive Semileptonic B-Meson Decays at Belle II

We present the first measurement of the ratio of branching fractions of inclusive semileptonic B-meson decays, R(X_{e/μ})=B(B→Xeν)/B(B→Xμν), a precision test of electron-muon universality, using data corresponding to 189  fb^{-1} from electron-positron collisions collected with the Belle II detector. In events where the partner B meson is fully reconstructed, we use fits to the lepton momentum spectra above 1.3  GeV/c to obtain R(X_{e/μ})=1.007±0.009(stat)±0.019(syst), which is the most precise lepton-universality test of its kind and agrees with the standard-model expectation.

First Measurement of the Michel Parameter ξ^{'} in the τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} Decay at Belle

We report the first measurement of the Michel parameter ξ^{'} in the τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decay with a new method proposed just recently. The measurement is based on the reconstruction of the τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} events with subsequent muon decay in flight in the Belle central drift chamber. The analyzed data sample of 988  fb^{-1} collected by the Belle detector corresponds to approximately 912×10^{6} τ^{+}τ^{-} pairs. We measure ξ^{'}=0.22±0.94(stat)±0.42(syst), which is in agreement with the standard model prediction of ξ^{'}=1. Statistical uncertainty dominates in this study, being a limiting factor, while systematic uncertainty is well under control. Our analysis proved the practicability of this promising method and its prospects for further precise measurement in future experiments.

Search for the Lepton Flavor Violating Decays B^{+}→K^{+}τ^{±}ℓ^{∓} (ℓ=e, μ) at Belle

We present a search for the lepton flavor violating decays B^{+}→K^{+}τ^{±}ℓ^{∓}, with ℓ=(e,μ), using the full data sample of 772×10^{6}  BB[over ¯] pairs recorded by the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode. We find no evidence for B^{±}→K^{±}τℓ decays and set upper limits on their branching fractions at the 90% confidence level in the (1-3)×10^{-5} range. The obtained limits are the world's best results.

Measurements of Normalized Differential Cross Sections of Inclusive π^{0} and K_{S}^{0} Production in e^{+}e^{-} Annihilation at Energies from 2.2324 to 3.6710 GeV

Based on electron positron collision data collected with the BESIII detector operating at the BEPCII storage rings, the differential cross sections of inclusive π^{0} and K_{S}^{0} production as a function of hadron momentum, normalized by the total cross section of the e^{+}e^{-}→hadrons process, are measured at six center-of-mass energies from 2.2324 to 3.6710 GeV. Our results, which cover a relative hadron energy range from 0.1 to 0.9, significantly deviate from several theoretical calculations based on existing fragmentation functions.

Search for an Invisible Z^{'} in a Final State with Two Muons and Missing Energy at Belle II

The L_{μ}-L_{τ} extension of the standard model predicts the existence of a lepton-flavor-universality-violating Z^{'} boson that couples only to the heavier lepton families. We search for such a Z^{'} through its invisible decay in the process e^{+}e^{-}→μ^{+}μ^{-}Z^{'}. We use a sample of electron-positron collisions at a center-of-mass energy of 10.58 GeV collected by the Belle II experiment in 2019-2020, corresponding to an integrated luminosity of 79.7  fb^{-1}. We find no excess over the expected standard-model background. We set 90%-confidence-level upper limits on the cross section for this process as well as on the coupling of the model, which ranges from 3×10^{-3} at low Z^{'} masses to 1 at Z^{'} masses of 8  GeV/c^{2}.

[Clinical and pathological characteristics of immune-mediated liver injury caused by immune checkpoint inhibitors]

Objective: Cancer immunotherapy can lead to various side effects, termed immune-related adverse events (irAE). This study summarized and analyzed the clinical and pathological characteristics of immune-mediated liver injury caused by immune checkpoint inhibitors (ILICI). Methods: This is a retrospective case series study involving 11 patients diagnosed with ILICI at the Peking Union Medical College Hospital from November 2019 to November 2021. Patient demographic information and clinical data, including gender, age, ILICI onset, clinical and radiological manifestations, pathological features, treatment, and resumption of ICI were retrospectively collected and analyzed. Results: The patients were primarily males (9/11) with a median age of 65 (range: 32-73) years. ICI mainly resulted in either partial remission (4/11) or stable disease (3/11). ILICI occurred after a median of two cycles of anti-programmed cell death-1 (PD-1) therapy, with a median time from the initial and last anti-PD-1 therapy to ILICI onset of 57 days and 17 days, respectively. ILICI was mostly severe (3/11) or very severe (6/11). While the clinical and radiological manifestations were non-specific, the pathological features were active lobular hepatitis and portal inflammation, with prominent CD8⁺T lymphocyte infiltration. The basic treatment was hepatoprotective drugs (10/11). Glucocorticoids were used as the primary therapy (9/11) but were ineffective in 4 of 9 cases. Of these, 3 of 9 cases received combined treatment with mycophenolate mofetil (MMF), only one of whom achieved remission. By the end of the study, 2 of 11 cases had resumed ICI and neither had experienced an ILICI relapse. Conclusion: The ILICI patients in this study had a corresponding history of ICI treatment and pathological features. The main treatment included hepatoprotective drugs and glucocorticoids. Immunosuppressive drugs were added for some cases but had poor efficacy.

Current status and future prospects of TB digital treatment adherence technology use in China

BACKGROUND: Digital treatment adherence technologies (DATs) have been recommended by the Chinese National Tuberculosis Programme since 2015. However, until now the extent to which DATs have been adopted in China remain unclear. In this study, we aimed to understand the current status and future prospects of DAT use in China.METHODS: A cross-sectional study was undertaken to collect data from all 2,884 county-level TB-designated institutions across China using a quantitative questionnaire and extraction of information from the Chinese TB information management system. Data were collected between 1 July 2020 and 30 June 2021.RESULTS: All of the 2,884 county-level TB-designated institutions responded to the questionnaire. We found that the utilisation rate of DATs in China was 21.5% (n = 620). Among those using DATs, the uptake of DATs among TB patients was 31.0%. Lack of financial, policy and technology support were the main barriers to adoption and scale up DATs at the institution level.CONCLUSIONS: The use of DATs is in an early stage in China; however, the number of institutions who offer DATs have increased significantly after July 2020. To facilitate the use of DATs, the national TB programme should provide more financial, policy and technology support, and a national guideline is required.

[Comparison of the predictive value of Padua and the IMPEDE assessment scores for venous thromboembolism in patients with newly diagnosed multiple myeloma: A single institution experience]

Objective: To compare the predictive efficacy of the two thrombosis risk assessment scores (Padua and IMPEDE scores) in venous thromboembolism (VTE) within 6 months in patients with newly diagnosed multiple myeloma (NDMM) in China. Methods: This study reviewed the clinical data of 421 patients with NDMM hospitalized in Beijing Jishuitan Hospital from April 2014 to February 2022. The sensitivity, specificity, accuracy, and Youden index of the two scores were calculated to quantify the thrombus risk assessment of VTE by the Padua and IMPEDE scores. The receiver operating characteristics curves of the two evaluation scores were drawn. Results: The incidence of VTE was 14.73%. The sensitivity, specificity, accuracy, and Youden index of the Padua score were 100%, 0%, 14.7%, and 0% and that of the IMPEDE score was 79%, 44%, 49.2%, and 23%, respectively. The areas under the curve of Padua and IMPEDE risk assessment scores were 0.591 and 0.722, respectively. Conclusion: IMPEDE score is suitable for predicting VTE within 6 months in patients with NDMM.

Search for Lepton-Flavor-Violating τ Decays to a Lepton and an Invisible Boson at Belle II

We search for lepton-flavor-violating τ^{-}→e^{-}α and τ^{-}→μ^{-}α decays, where α is an invisible spin-0 boson. The search uses electron-positron collisions at 10.58 GeV center-of-mass energy with an integrated luminosity of 62.8  fb^{-1}, produced by the SuperKEKB collider and collected with the Belle II detector. We search for an excess in the lepton-energy spectrum of the known τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ} and τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ} decays. We report 95% confidence-level upper limits on the branching-fraction ratio B(τ^{-}→e^{-}α)/B(τ^{-}→e^{-}ν[over ¯]_{e}ν_{τ}) in the range (1.1-9.7)×10^{-3} and on B(τ^{-}→μ^{-}α)/B(τ^{-}→μ^{-}ν[over ¯]_{μ}ν_{τ}) in the range (0.7-12.2)×10^{-3} for α masses between 0 and 1.6  GeV/c^{2}. These results provide the most stringent bounds on invisible boson production from τ decays.

First Observation of Λπ^{+} and Λπ^{-} Signals near the K[over ¯]N(I=1) Mass Threshold in Λ_{c}^{+}→Λπ^{+}π^{+}π^{-} Decay

Using the data sample of 980  fb^{-1} collected with the Belle detector operating at the KEKB asymmetric-energy e^{+}e^{-} collider, we present the results of an investigation of the Λπ^{+} and Λπ^{-} invariant mass distributions looking for substructure in the decay Λ_{c}^{+}→Λπ^{+}π^{+}π^{-}. We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Λπ^{+} (Λπ^{-}) combination a mass of 1434.3±0.6(stat)±0.9(syst)  MeV/c^{2} [1438.5±0.9(stat)±2.5(syst)  MeV/c^{2}], an intrinsic width of 11.5±2.8(stat)±5.3(syst)  MeV/c^{2} [33.0±7.5(stat)±23.6(syst)  MeV/c^{2}] with a significance of 7.5σ (6.2σ). As these two signals are very close to the K[over ¯]N threshold, we also investigate the possibility of a K[over ¯]N cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.

Observation of a New X(3872) Production Process e^{+}e^{-}→ωX(3872)

Using 4.7  fb^{-1} of e^{+}e^{-} collision data at center-of-mass energies from 4.661 to 4.951 GeV collected by the BESIII detector at the BEPCII collider, we observe the X(3872) production process e^{+}e^{-}→ωX(3872) for the first time. The significance is 7.8σ, including both the statistical and systematic uncertainties. The e^{+}e^{-}→ωX(3872) Born cross section and the corresponding upper limit at 90% confidence level at each energy point are reported. The line shape of the cross section indicates that the ωX(3872) signals may be from the decays of some nontrivial structures.

Observation of e^{+}e^{-}→ωχ_{bJ}(1P) and Search for X_{b}→ωϒ(1S) at sqrt[s] near 10.75 GeV

We study the processes e^{+}e^{-}→ωχ_{bJ}(1P) (J=0, 1, or 2) using samples at center-of-mass energies sqrt[s]=10.701, 10.745, and 10.805 GeV, corresponding to 1.6, 9.8, and 4.7  fb^{-1} of integrated luminosity, respectively. These data were collected with the Belle II detector during special operations of the SuperKEKB collider above the ϒ(4S) resonance. We report the first observation of ωχ_{bJ}(1P) signals at sqrt[s]=10.745  GeV. By combining Belle II data with Belle results at sqrt[s]=10.867  GeV, we find energy dependencies of the Born cross sections for e^{+}e^{-}→ωχ_{b1,b2}(1P) to be consistent with the shape of the ϒ(10753) state. These data indicate that the internal structures of the ϒ(10753) and ϒ(10860) states may differ. Including data at sqrt[s]=10.653  GeV, we also search for the bottomonium equivalent of the X(3872) state decaying into ωϒ(1S). No significant signal is observed for masses between 10.45 and 10.65  GeV/c^{2}.

Evidence for the Cusp Effect in η' Decays into ηπ^{0}π^{0}

Using a sample of 4.3×10^{5} η^{'}→ηπ^{0}π^{0} events selected from the ten billion J/ψ event dataset collected with the BESIII detector, we study the decay η^{'}→ηπ^{0}π^{0} within the framework of nonrelativistic effective field theory. Evidence for a structure at π^{+}π^{-} mass threshold is observed in the invariant mass spectrum of π^{0}π^{0} with a statistical significance of around 3.5σ, which is consistent with the cusp effect as predicted by the nonrelativistic effective field theory. After introducing the amplitude for describing the cusp effect, the ππ scattering length combination a_{0}-a_{2} is determined to be 0.226±0.060_{stat}±0.013_{syst}, which is in good agreement with theoretical calculation of 0.2644±0.0051.

Measurement of the Λ_{c}^{+} Lifetime

An absolute measurement of the Λ_{c}^{+} lifetime is reported using Λ_{c}^{+}→pK^{-}π^{+} decays in events reconstructed from data collected by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. The total integrated luminosity of the data sample, which was collected at center-of-mass energies at or near the ϒ(4S) resonance, is 207.2  fb^{-1}. The result, τ(Λ_{c}^{+})=203.20±0.89±0.77  fs, where the first uncertainty is statistical and the second systematic, is the most precise measurement to date and is consistent with previous determinations.