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Isobaric enzymatic assays reveal depth-dependent variation in microbial ectoenzyme activities in the deepest ocean on Earth

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Science China Earth Sciences 2025年第1期68卷 185-194页

作者： Junwei CAO Jiahua WANG Hongge ZHANG Junhao DENG Binbin PAN Jiawang CHEN Li ZHANG Jiasong FANG College of Oceanography and Ecological Science Shanghai Ocean University Ocean College Zhejiang University laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology

Microbial ectoenzymes play essential roles in the transformation and mineralization of organic matter in the ***, conventional methods for measuring microbial ectoenzyme activities(MEAs) in the deep ocean under atmospheric conditions can misrepresent the metabolic activities of indigenous microbial communities. To overcome this limitation, we measured the activities of three microbial ectoenzymes(aminopeptidase, α-glucosidase, and β-glucosidase) under both atmospheric and in situ pressure conditions in seawater collected using pressure-retaining and non-pressure-retaining samplers in the Challenger Deep, Mariana Trench. In the case of aminopeptidase and α-glucosidase, the highest isobaric MEAs were observed in the surface layer(50 m), followed by those at abyssopelagic depths(4,000–6,000 m) for aminopeptidase, hadal realm(10,903 m)for α-glucosidase, while β-glucosidase activity exhibited the highest value at 10,903 m. Furthermore, the isobaric MEAs in hadal waters were commonly found to be higher than the decompressed counterparts, highlighting the importance of pressure-retaining sampling and isobaric enzymatic assays. The half-saturation constant(Km) showed a general decreasing trend with depth,suggesting that the deep ocean microbes might have adapted to the high-pressure and oligotrophic environment by increasing their ectoenzyme's affinity to substrate. Furthermore, particle-free MEAs contribute more to the total MEAs in the deep ocean than particle-associated MEAs, suggesting the significance of cell-associated and dissolved ectoenzymes in ocean *** study provides a foundation for future investigations of MEAs in the ocean and has important implications for understanding the dynamics of microbially mediated biogeochemical cycling in marine ecosystems.

关键词： Pressure-retaining sampling Microbial ectoenzyme activity Deep-sea microbes High pressure Mariana Trench

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Study of the s → dv■ rare hyperon decays in the Standard Model and new physics

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Chinese Physics C 2019年第9期43卷 26-32页

作者： Xiao-Hui Hu Zhen-Xing Zhao INPAC Shanghai Key Laboratory for Particle Physics and Cosmology MOE Key Laboratory for Particle Physics Astrophysics and CosmologySchool of Physics and Astronomy Shanghai Jiao-Tong University

FCNC processes offer important tools to test the Standard Model（SM）and to search for possible new *** this work,we investigate the s→dvv rare hyperon decays in SM and *** find that in SM the branching ratios for these rare hyperon decays range from 10-14 to *** all the errors in the form factors are included,we find that the final branching ratios for most decay modes have an uncertainty of about 5% to 10%.After taking into account the contribution from new physics,the generalized SUSY extension of SM and the minimal 331 model,the decay widths for these channels can be enhanced by a factor of 2～7.

关键词： branching ratios rare hyperon decays form factors light-front approach new physics

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On the production of hidden-flavored hadronic states at high energy

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Chinese Physics C 2018年第4期42卷 101-108页

作者： Wei Wang INPAC Shanghai Key Laboratory for Particle Physics and Cosmology MOE Key Laboratory for Particle Physics Astrophysics and Cosmology School of Physics and Astronomy Shanghai JiaoTong University Shanghai 200240 China

I discuss the production mechanism of hidden-flavored hadrons at high energy. Using e＋e-collisions and light-meson pair production in high energy exclusive processes, I demonstrate that hidden quark pairs do not necessarily participate in short-distance hard scattering. Implications are then explored in a few examples. Finally, I discuss the production mechanism of X（3872） in hadron collisions, where some misunderstandings have arisen in the literature.

关键词： hadron exotics high energy production molecule

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Unambiguously Resolving the Potential Neutrino Magnetic Moment Signal at Large Liquid Scintillator Detectors

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Chinese Physics Letters 2021年第11期38卷 18-22页

作者： Ziping Ye Feiyang Zhang Donglian Xu Jianglai Liu Tsung-Dao Lee Institute Shanghai 200240China INPAC and School of Physics and Astronomy Shanghai Jiao Tong UniversityShanghai 200240China shanghai laboratory for particle Physics and cosmology Key Laboratory for Particle Physics and Cosmology(MOE)Shanghai 200240China

Non-vanishing electromagnetic properties of neutrinos have been predicted by many theories beyond the Standard Model, and an enhanced neutrino magnetic moment can have profound implications for fundamental physics. The XENON1T experiment recently detected an excess of electron recoil events in the 1–7 keV energy range, which can be compatible with solar neutrino magnetic moment interaction at a most probable value of μ_(v) = 2.1 × 10^(-11)μ_(B).However, tritium backgrounds or solar axion interaction in this energy window are equally plausible *** multi-tonne noble liquid detectors will test these scenarios more in depth, but will continue to face similar ambiguity. We report a unique capability of future large liquid scintillator detectors to help resolve the potential neutrino magnetic moment scenario. With O(100) kton·year exposure of liquid scintillator to solar neutrinos, a sensitivity of μ_(v) < 10^(-11)μ_(B) can be reached at an energy threshold greater than 40 keV, where no tritium or solar axion events but only neutrino magnetic moment signal is still present.

关键词： Unambiguously Resolving the Potential Neutrino Magnetic Moment Signal at Large Liquid Scintillator Detectors

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Weak decays of heavy baryons in the light-front approach

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Chinese Physics C 2018年第9期42卷 1-14页

作者： Zhen-Xing Zhao INPAC.shanghai Key laboratory for particle Physics and cosmology MOE Key Lahoratory for Particle PhysicsAstrophysics and CosmologySchool of Physics and AstronomyShanghai Jiao-Tong UniversityShanghai 200240China

In this work, we analyse semi-leptonic and non-leptonic weak decays of the heavy baryons： Λ_b,Ξ_b,Ωb and Λ_c,Ξ_c,Ωc. For non-leptonic decay modes, we study only the factorizable channels induced by the external Wemission. The two spectator quarks in the baryonic transitions are treated as a diquark and form factors are calculated in the light-front approach. Using the results for form factors, we also calculate some corresponding semi-leptonic and non-leptonic decay widths. We find that our results are comparable with the available experimental data and other theoretical predictions. Decay branching fractions for many channels are found to reach the level 10^（-3）~10^（-2）,which is promising for discovery in future measurements at BESIII, LHCb and Belle II. The SU（3） symmetry in semi-leptonic decays is examined and sources of symmetry breaking are discussed.

关键词： heavy baryons weak decay light-front approach

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Understanding PDF uncertainty in W boson mass measurements

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Chinese Physics C 2022年第12期46卷 179-193页

作者： Jun Gao Dianyu Liu Keping Xie NPAC Shanghai Key Laboratory for Particle Physics and CosmologySchool of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Key laboratory for particle Astrophysics and cosmology(MOE) Shanghai 200240China Pittsburgh particle Physics Astrophysicsand Cosmology CenterDepartment of Physics and AstronomyUniversity of PittsburghPittsburghPA 15260USA

We study the dependence of the transverse mass distribution of charged leptons and the missing energy on parton distributions(PDFs)adapted to W boson mass measurements at the CDF and ATLAS *** compare the shape variations of the distribution induced by different PDFs and find that the spread of predictions from different PDF sets can be significantly larger than the PDF uncertainty predicted by a specific PDF *** suggest analyzing the experimental data using up-to-date PDFs to gain a better understanding of the PDF uncertainties in W boson mass *** also perform a series of Lagrange multiplier scans to identify the constraints on the transverse mass distribution imposed by individual data sets in the CT18 global *** the case of the CDF measurement,the distribution is mostly sensitive to d-quark PDFs in the intermediate x region,which are largely constrained by DIS and Drell-Yan data on deuteron targets and Tevatron lepton charge asymmetry data.

关键词： W-boson mass PDF uncertainty CT18

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Implications of the RK and R_(K*) anomalies

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Chinese Physics C 2018年第1期42卷 52-62页

作者：王伟赵帅 INPAC Shanghai Key Laboratory for Particle Physics and Cosmology School of Physics and Astronomy Shanghai Jiao-Tong University

We discuss the implications of the recently reported R_K and R_（K＊） anomalies, the lepton flavor nonuniversality in the B → Kl~＋l^-and B → K~＊l~＋~l- decay channels. Using two sets of hadronic inputs of form factors, we perform a fit of new physics to the R_K and R_（K＊） data, and significant new physics contributions are found. We suggest the study of lepton flavor universality in a number of related rare B,Bs,Bc and Λb decay channels, and in particular we give predictions for the μ-to-e ratios of decay widths with different polarizations of the final state particles, and of the b → dl~＋l^- processes, which are presumably more sensitive to the structure of the underlying new physics. With the new physics contributions embedded in the Wilson coefficients, we present theoretical predictions for lepton flavor non-universality in these processes.

关键词： R_K and R_(K*) anomalies lepton flavor universality violation rare B decay

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Constraints on the skewness coefficient of symmetric nuclear matter within the nonlinear relativistic mean field model

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Nuclear Science and Techniques 2017年第12期28卷 279-287页

作者： Bao-Jun Cai Lie-Wen Chen School of Physics and Astronomy and shanghai Key laboratory for particle Physics and cosmology Shanghai Jiao Tong UniversityShanghai 200240China

Within the nonlinear relativistic mean field(NLRMF) model, we show that both the pressure of symmetric nuclear matter at supra-saturation densities and the maximum mass of neutron stars are sensitive to the skewness coefficient, J_0, of symmetric nuclear matter. Using experimental constraints on the pressure of symmetric nuclear matter at supra-saturation densities from flow data in heavy-ion collisions and the astrophysical observation of a large mass neutron star PSR J0348+0432, with the former favoring a smaller J_0 while the latter favors a larger J_0, we extract a constraint of -494 MeV≤J_0≤-10 MeV based on the NL-RMF model. This constraint is compared with the results obtained in other analyses.

关键词： Equation of state of nuclear matter Heavy-ion collisions Neutron stars

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Weak decays of doubly heavy baryons:"decay constants"

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Chinese Physics C 2018年第12期42卷 9-18页

作者： Xiao-Hui nu Yue-Long Shen Wei Wang Zhen-Xing Zhao INPAC Shanghai Key Laboratory for Particle Physics and CosmologyMOE Key Laboratory for Particle PhysicsAstrophysics and CosmologySchool of Physics and AstronomyShanghai Jiao-Tong UniversityShanghai 200240China College of Information Science and Engineering Ocean University of ChinaQingdao 266100China

Inspired by the recent observation of the ∑c^＋c^＋ by the LHCb Collaboration, we explore the ＂decay constants＂ of doubly heavy baryons in the framework of QCD sum rules. With the ∑cc,∑bb, and Ωcc,Ωbc,Ωbb baryons interpolated by three-quark operators, we calculate the correlation functions using the operator product expansion and include the contributions from operators up to dimension six. On the hadron side, we consider both contributions from the lowest-lying states with J^P 1/2^＋ and from negative parity baryons with JP=1/2^-. We find that the results are stable and the contaminations from negative parity baryons are not severe. These results are ingredients for the QCD study of weak decays and other properties of doubly-heavy baryons.

关键词： doubly heavy baryons decay constant QCD sum rules

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Bayesian inference on isospin splitting of nucleon effective mass from giant resonances in^(208)Pb

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Chinese Physics C 2021年第6期45卷 158-166页

作者： Zhen Zhang Xue-Bin Feng Lie-Wen Chen Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China School of Physics and Astronomy Shanghai Key Laboratory for Particle Physics and Cosmologyand Key Laboratory for Particle Astrophysics and Cosmology(MOE)Shanghai Jiao Tong UniversityShanghai 200240China

From a Bayesian analysis of the electric dipole polarizability,the constrained energy of isovector giant dipole resonance,the peak energy of isocalar giant quadrupole resonance,and the constrained energy of isocalar gi-ant monopole resonance in 208Pb,we extract the isoscalar and isovector effective masses in nuclear matter at satura-tion density ρ0 as m^(*)_(s.0)/m=0.87^(+)_(-004) and m^(*)_(v.0)/m=0.78^(+006)_(-006),respectively,at 90%confdence *** con-straints obtained on m^(*)_(d.0) and m^(*)_(v.0) lead to a positive isospin splitting of nucleon effective mass in asymmetric nuclear matter of isospin asymmetry σ at ρ0 as m^(*)_(n-p)/m=(0.20^(0.15)_(0.14)σ.In addition,the symmetry energy at the subsatura-tion density ρ^(*)=0.05 fm^(-3) is determined to be E_(sym)(ρ^(*))=16.7±1.3 MeV at 90%confidence level.

关键词： nucleon effective mass isospin splitting of nucleon effective mass symmetry energy nuclear giant resonance Bayesian analysis

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