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1.
Nature ; 594(7861): 33-36, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34002091

RESUMO

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 1015 electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays1. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. 2). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

2.
Circ Res ; 132(2): e59-e77, 2023 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-36583384

RESUMO

BACKGROUND: PKA (protein kinase A)-mediated phosphorylation of cardiac RyR2 (ryanodine receptor 2) has been extensively studied for decades, but the physiological significance of PKA phosphorylation of RyR2 remains poorly understood. Recent determination of high-resolution 3-dimensional structure of RyR2 in complex with CaM (calmodulin) reveals that the major PKA phosphorylation site in RyR2, serine-2030 (S2030), is located within a structural pathway of CaM-dependent inactivation of RyR2. This novel structural insight points to a possible role of PKA phosphorylation of RyR2 in CaM-dependent inactivation of RyR2, which underlies the termination of Ca2+ release and induction of cardiac Ca2+ alternans. METHODS: We performed single-cell endoplasmic reticulum Ca2+ imaging to assess the impact of S2030 mutations on Ca2+ release termination in human embryonic kidney 293 cells. Here we determined the role of the PKA site RyR2-S2030 in a physiological setting, we generated a novel mouse model harboring the S2030L mutation and carried out confocal Ca2+ imaging. RESULTS: We found that mutations, S2030D, S2030G, S2030L, S2030V, and S2030W reduced the endoplasmic reticulum luminal Ca2+ level at which Ca2+ release terminates (the termination threshold), whereas S2030P and S2030R increased the termination threshold. S2030A and S2030T had no significant impact on release termination. Furthermore, CaM-wild-type increased, whereas Ca2+ binding deficient CaM mutant (CaM-M [a loss-of-function CaM mutation with all 4 EF-hand motifs mutated]), PKA, and Ca2+/CaMKII (CaM-dependent protein kinase II) reduced the termination threshold. The S2030L mutation abolished the actions of CaM-wild-type, CaM-M, and PKA, but not CaMKII, in Ca2+ release termination. Moreover, we showed that isoproterenol and CaM-M suppressed pacing-induced Ca2+ alternans and accelerated Ca2+ transient recovery in intact working hearts, whereas CaM-wild-type exerted an opposite effect. The impact of isoproterenol was partially and fully reversed by the PKA inhibitor N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide and the CaMKII inhibitor N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide individually and together, respectively. S2030L abolished the impact of CaM-wild-type, CaM-M, and N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide-sensitive component, but not the N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide-sensitive component, of isoproterenol.


Assuntos
Canal de Liberação de Cálcio do Receptor de Rianodina , Serina , Camundongos , Animais , Humanos , Isoproterenol/farmacologia , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Serina/metabolismo , Serina/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Calmodulina/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Isoquinolinas/farmacologia , Sulfonamidas/farmacologia , Cálcio/metabolismo , Miócitos Cardíacos/metabolismo , Retículo Sarcoplasmático/metabolismo
3.
Circ Res ; 133(2): 177-192, 2023 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-37325910

RESUMO

BACKGROUND: A loss-of-function cardiac ryanodine receptor (RyR2) mutation, I4855M+/-, has recently been linked to a new cardiac disorder termed RyR2 Ca2+ release deficiency syndrome (CRDS) as well as left ventricular noncompaction (LVNC). The mechanism by which RyR2 loss-of-function causes CRDS has been extensively studied, but the mechanism underlying RyR2 loss-of-function-associated LVNC is unknown. Here, we determined the impact of a CRDS-LVNC-associated RyR2-I4855M+/- loss-of-function mutation on cardiac structure and function. METHODS: We generated a mouse model expressing the CRDS-LVNC-associated RyR2-I4855M+/- mutation. Histological analysis, echocardiography, ECG recording, and intact heart Ca2+ imaging were performed to characterize the structural and functional consequences of the RyR2-I4855M+/- mutation. RESULTS: As in humans, RyR2-I4855M+/- mice displayed LVNC characterized by cardiac hypertrabeculation and noncompaction. RyR2-I4855M+/- mice were highly susceptible to electrical stimulation-induced ventricular arrhythmias but protected from stress-induced ventricular arrhythmias. Unexpectedly, the RyR2-I4855M+/- mutation increased the peak Ca2+ transient but did not alter the L-type Ca2+ current, suggesting an increase in Ca2+-induced Ca2+ release gain. The RyR2-I4855M+/- mutation abolished sarcoplasmic reticulum store overload-induced Ca2+ release or Ca2+ leak, elevated sarcoplasmic reticulum Ca2+ load, prolonged Ca2+ transient decay, and elevated end-diastolic Ca2+ level upon rapid pacing. Immunoblotting revealed increased level of phosphorylated CaMKII (Ca2+-calmodulin dependent protein kinases II) but unchanged levels of CaMKII, calcineurin, and other Ca2+ handling proteins in the RyR2-I4855M+/- mutant compared with wild type. CONCLUSIONS: The RyR2-I4855M+/- mutant mice represent the first RyR2-associated LVNC animal model that recapitulates the CRDS-LVNC overlapping phenotype in humans. The RyR2-I4855M+/- mutation increases the peak Ca2+ transient by increasing the Ca2+-induced Ca2+ release gain and the end-diastolic Ca2+ level by prolonging Ca2+ transient decay. Our data suggest that the increased peak-systolic and end-diastolic Ca2+ levels may underlie RyR2-associated LVNC.


Assuntos
Cardiopatias Congênitas , Canal de Liberação de Cálcio do Receptor de Rianodina , Animais , Humanos , Camundongos , Arritmias Cardíacas/metabolismo , Cálcio/metabolismo , Sinalização do Cálcio/fisiologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Cardiopatias Congênitas/metabolismo , Miócitos Cardíacos/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/metabolismo
4.
Nature ; 572(7769): 347-351, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31278385

RESUMO

The high-conductance intracellular calcium (Ca2+) channel RyR2 is essential for the coupling of excitation and contraction in cardiac muscle. Among various modulators, calmodulin (CaM) regulates RyR2 in a Ca2+-dependent manner. Here we reveal the regulatory mechanism by which porcine RyR2 is modulated by human CaM through the structural determination of RyR2 under eight conditions. Apo-CaM and Ca2+-CaM bind to distinct but overlapping sites in an elongated cleft formed by the handle, helical and central domains. The shift in CaM-binding sites on RyR2 is controlled by Ca2+ binding to CaM, rather than to RyR2. Ca2+-CaM induces rotations and intradomain shifts of individual central domains, resulting in pore closure of the PCB95 and Ca2+-activated channel. By contrast, the pore of the ATP, caffeine and Ca2+-activated channel remains open in the presence of Ca2+-CaM, which suggests that Ca2+-CaM is one of the many competing modulators of RyR2 gating.


Assuntos
Calmodulina/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Apoproteínas/metabolismo , Sítios de Ligação , Cafeína/metabolismo , Cálcio/metabolismo , Microscopia Crioeletrônica , Humanos , Modelos Moleculares , Reprodutibilidade dos Testes , Canal de Liberação de Cálcio do Receptor de Rianodina/química , Suínos
5.
J Neurosci ; 43(8): 1441-1454, 2023 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-36627208

RESUMO

It is well established that ryanodine receptors (RyanRs) are overactive in Alzheimer's disease (AD), and it has been suggested that inhibition of RyanR is potentially beneficial for AD treatment. In the present study, we explored a potential connection between basal RyanR activity and autophagy in neurons. Autophagy plays an important role in clearing damaged organelles and long-lived protein aggregates, and autophagy dysregulation occurs in both AD patients and AD animal models. Autophagy is known to be regulated by intracellular calcium (Ca2+) signals, and our results indicated that basal RyanR2 activity in hippocampal neurons inhibited autophagy through activation of calcineurin and the resulting inhibition of the AMPK (AMP-activated protein kinase)-ULK1 (unc-51-like autophagy-activating kinase 1) pathway. Thus, we hypothesized that increased basal RyanR2 activity in AD may lead to the inhibition of neuronal autophagy and accumulation of ß-amyloid. To test this hypothesis, we took advantage of the RyanR2-E4872Q knock-in mouse model (EQ) in which basal RyanR2 activity is reduced because of shortened channel open time. We discovered that crossing EQ mice with the APPKI and APPPS1 mouse models of AD (both males and females) rescued amyloid accumulation and LTP impairment in these mice. Our results revealed that reduced basal activity of RyanR2-EQ channels disinhibited the autophagic pathway and led to increased amyloid clearance in these models. These data indicated a potential pathogenic outcome of RyanR2 overactivation in AD and also provided additional targets for therapeutic intervention in AD. Basal activity of ryanodine receptors controls neuronal autophagy and contributes to development of the AD phenotype.SIGNIFICANCE STATEMENT It is well established that neuronal autophagy is impaired in Alzheimer's disease (AD). Our results suggest that supranormal calcium (Ca2+) release from endoplasmic reticulum contributes to the inhibition of autophagy in AD and that reduction in basal activity of type 2 ryanodine receptors disinhibits the neuronal autophagic pathway and leads to increased amyloid clearance in AD models. Our findings directly link neuronal Ca2+ dysregulation with autophagy dysfunction in AD and point to additional targets for therapeutic intervention.


Assuntos
Doença de Alzheimer , Autofagia , Canal de Liberação de Cálcio do Receptor de Rianodina , Animais , Feminino , Masculino , Camundongos , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Autofagia/genética , Autofagia/fisiologia , Cálcio/metabolismo , Modelos Animais de Doenças , Camundongos Transgênicos , Mutação , Neurônios/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo
6.
J Physiol ; 602(8): 1509-1518, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36866974

RESUMO

Increasing evidence suggests that simply reducing ß-amyloid (Aß) plaques may not significantly affect the progression of Alzheimer's disease (AD). There is also increasing evidence indicating that AD progression is driven by a vicious cycle of soluble Aß-induced neuronal hyperactivity. In support of this, it has recently been shown that genetically and pharmacologically limiting ryanodine receptor 2 (RyR2) open time prevents neuronal hyperactivity, memory impairment, dendritic spine loss and neuronal cell death in AD mouse models. By contrast, increased RyR2 open probability (Po) exacerbates the onset of familial AD-associated neuronal dysfunction and induces AD-like defects in the absence of AD-causing gene mutations. Thus, RyR2-dependent modulation of neuronal hyperactivity represents a promising new target for combating AD.

7.
Ann Oncol ; 35(8): 718-727, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38729566

RESUMO

BACKGROUND: In MONARCH 2, the addition of abemaciclib to fulvestrant significantly improved both progression-free survival (PFS) and overall survival (OS) in patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC) with disease progression on prior endocrine therapy. In MONARCH 3, the addition of abemaciclib to a nonsteroidal aromatase inhibitor (NSAI) as initial therapy for HR+, HER2- ABC significantly improved PFS. Here, we present the prespecified final OS results for MONARCH 3. PATIENTS AND METHODS: MONARCH 3 is a randomized, double-blind, phase III study of abemaciclib plus NSAI (anastrozole or letrozole) versus placebo plus NSAI in postmenopausal women with HR+, HER2- ABC without prior systemic therapy in the advanced setting. The primary objective was investigator-assessed PFS; OS was a gated secondary endpoint, and chemotherapy-free survival was an exploratory endpoint. RESULTS: A total of 493 women were randomized 2 : 1 to receive abemaciclib plus NSAI (n = 328) or placebo plus NSAI (n = 165). After a median follow-up of 8.1 years, there were 198 OS events (60.4%) in the abemaciclib arm and 116 (70.3%) in the placebo arm (hazard ratio, 0.804; 95% confidence interval 0.637-1.015; P = 0.0664, non-significant). Median OS was 66.8 versus 53.7 months for abemaciclib versus placebo. In the subgroup with visceral disease, there were 113 OS events (65.3%) in the abemaciclib arm and 65 (72.2%) in the placebo arm (hazard ratio, 0.758; 95% confidence interval 0.558-1.030; P = 0.0757, non-significant). Median OS was 63.7 months versus 48.8 months for abemaciclib versus placebo. The previously demonstrated PFS benefit was sustained, and chemotherapy-free survival numerically improved with the addition of abemaciclib. No new safety signals were observed. CONCLUSIONS: Abemaciclib combined with an NSAI resulted in clinically meaningful improvement in median OS (intent-to-treat population: 13.1 months; subgroup with visceral disease: 14.9 months) in patients with HR+ HER2- ABC; however, statistical significance was not reached.


Assuntos
Aminopiridinas , Protocolos de Quimioterapia Combinada Antineoplásica , Inibidores da Aromatase , Benzimidazóis , Neoplasias da Mama , Letrozol , Receptor ErbB-2 , Receptores de Estrogênio , Receptores de Progesterona , Humanos , Feminino , Aminopiridinas/administração & dosagem , Aminopiridinas/uso terapêutico , Benzimidazóis/administração & dosagem , Benzimidazóis/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Neoplasias da Mama/mortalidade , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Receptor ErbB-2/metabolismo , Receptor ErbB-2/antagonistas & inibidores , Método Duplo-Cego , Letrozol/administração & dosagem , Letrozol/uso terapêutico , Inibidores da Aromatase/uso terapêutico , Inibidores da Aromatase/administração & dosagem , Pessoa de Meia-Idade , Idoso , Receptores de Progesterona/metabolismo , Receptores de Estrogênio/metabolismo , Anastrozol/uso terapêutico , Anastrozol/administração & dosagem , Adulto , Idoso de 80 Anos ou mais , Intervalo Livre de Progressão
8.
Nat Mater ; 22(7): 860-866, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37142739

RESUMO

Thin layers of in-plane anisotropic materials can support ultraconfined polaritons, whose wavelengths depend on the propagation direction. Such polaritons hold potential for the exploration of fundamental material properties and the development of novel nanophotonic devices. However, the real-space observation of ultraconfined in-plane anisotropic plasmon polaritons (PPs)-which exist in much broader spectral ranges than phonon polaritons-has been elusive. Here we apply terahertz nanoscopy to image in-plane anisotropic low-energy PPs in monoclinic Ag2Te platelets. The hybridization of the PPs with their mirror image-by placing the platelets above a Au layer-increases the direction-dependent relative polariton propagation length and the directional polariton confinement. This allows for verifying a linear dispersion and elliptical isofrequency contour in momentum space, revealing in-plane anisotropic acoustic terahertz PPs. Our work shows high-symmetry (elliptical) polaritons on low-symmetry (monoclinic) crystals and demonstrates the use of terahertz PPs for local measurements of anisotropic charge carrier masses and damping.


Assuntos
Acústica , Plaquetas , Anisotropia , Peso Molecular
9.
Phys Rev Lett ; 133(8): 081901, 2024 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-39241714

RESUMO

Using data samples collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 3.80 to 4.95 GeV, corresponding to an integrated luminosity of 20 fb^{-1}, a measurement of Born cross sections for the e^{+}e^{-}→D^{0}D[over ¯]^{0} and D^{+}D^{-} processes is presented with unprecedented precision. Many clear peaks in the line shape of e^{+}e^{-}→D^{0}D[over ¯]^{0} and D^{+}D^{-} around the mass range of G(3900), ψ(4040), ψ(4160), Y(4260), and ψ(4415), etc., are foreseen. These results offer crucial experimental insights into the nature of hadron production in the open-charm region.

10.
Phys Rev Lett ; 133(10): 101902, 2024 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-39303247

RESUMO

The J/ψ, ψ(3686)→Σ^{0}Σ[over ¯]^{0} processes and subsequent decays are studied using the world's largest J/ψ and ψ(3686) data samples collected with the BESIII detector. The parity-violating decay parameters of the decays Σ^{0}→Λγ and Σ[over ¯]^{0}→Λ[over ¯]γ, α_{Σ^{0}}=-0.0017±0.0021±0.0018 and α[over ¯]_{Σ^{0}}=0.0021±0.0020±0.0022, are measured for the first time. The strong CP symmetry is tested in the decays of the Σ^{0} hyperons for the first time by measuring the asymmetry A_{CP}^{Σ}=α_{Σ^{0}}+α[over ¯]_{Σ^{0}}=(0.4±2.9±1.3)×10^{-3}. The weak CP test is performed in the subsequent decays of their daughter particles Λ and Λ[over ¯]. Also for the first time, the transverse polarizations of the Σ^{0} hyperons in J/ψ and ψ(3686) decays are observed with opposite directions, and the ratios between the S-wave and D-wave contributions of the J/ψ, ψ(3686)→Σ^{0}Σ[over ¯]^{0} decays are obtained. These results are crucial to understand the decay dynamics of the charmonium states and the production mechanism of the Σ^{0}-Σ[over ¯]^{0} pairs.

11.
Phys Rev Lett ; 132(23): 231902, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38905649

RESUMO

Using (10.087±0.044)×10^{9} J/ψ events collected with the BESIII detector at the BEPCII storage ring, the processes Λp→Λp and Λ[over ¯]p→Λ[over ¯]p are studied, where the Λ/Λ[over ¯] baryons are produced in the process J/ψ→ΛΛ[over ¯] and the protons are the hydrogen nuclei in the cooling oil of the beam pipe. Clear signals are observed for the two reactions. The cross sections in -0.9≤cosθ_{Λ/Λ[over ¯]}≤0.9 are measured to be σ(Λp→Λp)=(12.2±1.6_{stat}±1.1_{syst}) and σ(Λ[over ¯]p→Λ[over ¯]p)=(17.5±2.1_{stat}±1.6_{syst}) mb at the Λ/Λ[over ¯] momentum of 1.074 GeV/c within a range of ±0.017 GeV/c, where the θ_{Λ/Λ[over ¯]} are the scattering angles of the Λ/Λ[over ¯] in the Λp/Λ[over ¯]p rest frames. Furthermore, the differential cross sections of the two reactions are also measured, where there is a slight tendency of forward scattering for Λp→Λp, and a strong forward peak for Λ[over ¯]p→Λ[over ¯]p. We present an approach to extract the total elastic cross sections by extrapolation. The study of Λ[over ¯]p→Λ[over ¯]p represents the first study of antihyperon-nucleon scattering, and these new measurements will serve as important inputs for the theoretical understanding of the (anti)hyperon-nucleon interaction.

12.
Phys Rev Lett ; 133(2): 021901, 2024 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-39073971

RESUMO

Using data samples collected with the BESIII detector operating at the BEPCII storage ring, the cross section of the inclusive process e^{+}e^{-}→η+X, normalized by the total cross section of e^{+}e^{-}→hadrons, is measured at eight center-of-mass energy points from 2.0000 to 3.6710 GeV. These are the first measurements with momentum dependence in this energy region. Our measurement shows a significant discrepancy compared to the existing fragmentation functions. To address this discrepancy, a new QCD analysis is performed at the next-to-next-to-leading order with hadron mass corrections and higher twist effects, which can explain both the established high-energy data and our measurements reasonably well.

13.
Phys Rev Lett ; 133(7): 071501, 2024 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-39213544

RESUMO

On 9 October 2022, the Large High Altitude Air Shower Observatory (LHAASO) reported the observation of the very early TeV afterglow of the brightest-of-all-time gamma-ray burst 221009A, recording the highest photon statistics in the TeV band ever obtained from a gamma-ray burst. We use this unique observation to place stringent constraints on the energy dependence of the speed of light in vacuum, a manifestation of Lorentz invariance violation (LIV) predicted by some quantum gravity (QG) theories. Our results show that the 95% confidence level lower limits on the QG energy scales are E_{QG,1}>10 times the Planck energy E_{Pl} for the linear LIV effect, and E_{QG,2}>6×10^{-8}E_{Pl} for the quadratic LIV effect. Our limits on the quadratic LIV case improve previous best bounds by factors of 5-7.

14.
Phys Rev Lett ; 132(15): 151901, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38682972

RESUMO

Using a sample of (10087±44)×10^{6} J/ψ events, which is about 45 times larger than that was previously analyzed, a further investigation on the J/ψ→γ3(π^{+}π^{-}) decay is performed. A significant distortion at 1.84 GeV/c^{2} in the line shape of the 3(π^{+}π^{-}) invariant mass spectrum is observed for the first time, which could be resolved by two overlapping resonant structures, X(1840) and X(1880). The new state X(1880) is observed with a statistical significance larger than 10σ. The mass and width of X(1880) are determined to be 1882.1±1.7±0.7 MeV/c^{2} and 30.7±5.5±2.4 MeV, respectively, which indicates the existence of a pp[over ¯] bound state.

15.
Phys Rev Lett ; 132(18): 181901, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38759175

RESUMO

Based on (10087±44)×10^{6} J/ψ events collected with the BESIII detector, a partial wave analysis of the decay J/ψ→γK_{S}^{0}K_{S}^{0}η^{'} is performed. The mass and width of the X(2370) are measured to be 2395±11(stat)_{-94}^{+26}(syst) MeV/c^{2} and 188_{-17}^{+18}(stat)_{-33}^{+124}(syst) MeV, respectively. The corresponding product branching fraction is B[J/ψ→γX(2370)]×B[X(2370)→f_{0}(980)η^{'}]×B[f_{0}(980)→K_{S}^{0}K_{S}^{0}]=(1.31±0.22(stat)_{-0.84}^{+2.85}(syst))×10^{-5}. The statistical significance of the X(2370) is greater than 11.7σ and the spin parity is determined to be 0^{-+} for the first time. The measured mass and spin parity of the X(2370) are consistent with the predictions of the lightest pseudoscalar glueball.

16.
Phys Rev Lett ; 132(16): 161901, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38701481

RESUMO

We present measurements of the Born cross sections for the processes e^{+}e^{-}→ωχ_{c1} and ωχ_{c2} at center-of-mass energies sqrt[s] from 4.308 to 4.951 GeV. The measurements are performed with data samples corresponding to an integrated luminosity of 11.0 fb^{-1} collected with the BESIII detector operating at the Beijing Electron Positron Collider storage ring. Assuming the e^{+}e^{-}→ωχ_{c2} signals come from a single resonance, the mass and width are determined to be M=(4413.6±9.0±0.8) MeV/c^{2} and Γ=(110.5±15.0±2.9) MeV, respectively, which is consistent with the parameters of the well-established resonance ψ(4415). In addition, we also use one single resonance to describe the e^{+}e^{-}→ωχ_{c1} line shape and determine the mass and width to be M=(4544.2±18.7±1.7) MeV/c^{2} and Γ=(116.1±33.5±1.7) MeV, respectively. The structure of this line shape, observed for the first time, requires further understanding.

17.
Phys Rev Lett ; 132(10): 101801, 2024 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-38518329

RESUMO

Using (10087±44)×10^{6} J/ψ events collected with the BESIII detector, numerous Ξ^{-} and Λ decay asymmetry parameters are simultaneously determined from the process J/ψ→Ξ^{-}Ξ[over ¯]^{+}→Λ(pπ^{-})π^{-}Λ[over ¯](n[over ¯]π^{0})π^{+} and its charge-conjugate channel. The precisions of α_{Λ0} for Λ→nπ^{0} and α[over ¯]_{Λ0} for Λ[over ¯]→n[over ¯]π^{0} compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of Λ→nπ^{0} to that of Λ→pπ^{-}, ⟨α_{Λ0}⟩/⟨α_{Λ-}⟩, is determined to be 0.873±0.012_{-0.010}^{+0.011}, where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity more than 5σ, which signifies the existence of the ΔI=3/2 transition in Λ for the first time. Besides, we test for CP symmetry in Ξ^{-}→Λπ^{-} and in Λ→nπ^{0} with the best precision to date.

18.
Phys Rev Lett ; 132(13): 131901, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38613263

RESUMO

We present cross sections for the reaction e^{+}e^{-}→K_{S}^{0}K_{L}^{0} at center-of-mass energies ranging from 3.51 to 4.95 GeV using data samples collected in the BESIII experiment, corresponding to a total integrated luminosity of 26.5 fb^{-1}. The ratio of neutral-to-charged kaon form factors at large momentum transfers (12

19.
Phys Rev Lett ; 132(13): 131002, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38613275

RESUMO

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15 PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

20.
Phys Rev Lett ; 132(13): 131903, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38613307

RESUMO

We perform for the first time an amplitude analysis of the decay D^{+}→K_{S}^{0}π^{+}η and report the observation of the decay D^{+}→K_{S}^{0}a_{0}(980)^{+} using 2.93 fb^{-1} of e^{+}e^{-} collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector. As the only W-annihilation-free decay among D to a_{0}(980) pseudoscalar, D^{+}→K_{S}^{0}a_{0}(980)^{+} is the ideal decay in extracting the contributions of the W-emission amplitudes involving a_{0}(980) and to study the final-state interactions. The absolute branching fraction of D^{+}→K_{S}^{0}π^{+}η is measured to be (1.27±0.04_{stat}±0.03_{syst})%. The branching fractions of intermediate processes D^{+}→K_{S}^{0}a_{0}(980)^{+} with a_{0}(980)^{+}→π^{+}η and D^{+}→π^{+}K[over ¯]_{0}^{*}(1430)^{0} with K[over ¯]_{0}^{*}(1430)^{0}→K_{S}^{0}η are measured to be (1.33±0.05_{stat}±0.04_{syst})% and (0.14±0.03_{stat}±0.01_{syst})%, respectively.

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