Inspired by the X(4140)structure reported in the J/ψφsystem by the CDF experiment in 2009,a series of searches have been carried out in theJ/ψφand J/ψK channels,leading to the claim of ten structures in the B→J...Inspired by the X(4140)structure reported in the J/ψφsystem by the CDF experiment in 2009,a series of searches have been carried out in theJ/ψφand J/ψK channels,leading to the claim of ten structures in the B→J/ψφK system.This article provides a comprehensive review of experimental developments,from the initial evidence of X(4140)at CDF to the amplitude analyses and diffractive process investigations by the LHCb experiment,as well as theoretical interpretations of these states.A triplet of J^(PC)=1++states with relatively large mass splittings[about 200MeV(natural units are adopted)]has been identified in the J/ψφsystem by LHCb.Their mass-squared values align approximately linearly with a possible radial quantum number,suggesting that the triplet may represent a radially excited family.For X(4140),the first state in the triplet,its width reported by LHCb is inconsistent with that measured by other experiments,and possible reasons for this discrepancy are discussed.A potential connection between an excess at 4.35 GeV in the J/ψφmass spectrum reported by the Belle experiment through a two-photon process and a potential spin-2 excess in the LHCb data is also investigated.In addition,potential parallels between the J/ψφand J/ψJ/ψsystems,both composed of two vector mesons,are discussed.The continued interest in,and complexity of,these systems underscore the necessity of further experimental exploration with increased statistical precision across a variety of experiments,particularly those with relatively flat efficiency across the Dalitz plot.The J/ψω,φφ,ρω,andρφsystems are mentioned,and the prospects for the J/ψγandγγsystems,are also highlighted.展开更多
We present an analytical treatment of the pulsar radio emission height as a function of phase based on a set of simplifying assumptions.Assuming a dipole field geometry,the emission height can be expressed as a functi...We present an analytical treatment of the pulsar radio emission height as a function of phase based on a set of simplifying assumptions.Assuming a dipole field geometry,the emission height can be expressed as a function of phase and the impact angle.We found that:(1)The emission height is a quadratic function of the phase,given the magnetospheric geometry.The emission height is higher at the edge of the pulse profile than at the center.(2)The emission height is also a quadratic function of the impact angle.This point can be compared directly with the observations of the geodetic precessing pulsar PSR J1906+0746.(3)A larger inclination angle may imply a higher emission height,when other parameters are similar.(4)By assuming curvature radiation,or inverse Compton scattering,the Lorentz factor of the radio emitting particles can be obtained as a function of phase.展开更多
基金partially supported by the Natural Science Foundation of China(Grant Nos.12075123,12061141002,and 12535004)the Ministry of Science and Technology of China(Grant Nos.2023YFA1605804 and 2024YFA1610501)。
文摘Inspired by the X(4140)structure reported in the J/ψφsystem by the CDF experiment in 2009,a series of searches have been carried out in theJ/ψφand J/ψK channels,leading to the claim of ten structures in the B→J/ψφK system.This article provides a comprehensive review of experimental developments,from the initial evidence of X(4140)at CDF to the amplitude analyses and diffractive process investigations by the LHCb experiment,as well as theoretical interpretations of these states.A triplet of J^(PC)=1++states with relatively large mass splittings[about 200MeV(natural units are adopted)]has been identified in the J/ψφsystem by LHCb.Their mass-squared values align approximately linearly with a possible radial quantum number,suggesting that the triplet may represent a radially excited family.For X(4140),the first state in the triplet,its width reported by LHCb is inconsistent with that measured by other experiments,and possible reasons for this discrepancy are discussed.A potential connection between an excess at 4.35 GeV in the J/ψφmass spectrum reported by the Belle experiment through a two-photon process and a potential spin-2 excess in the LHCb data is also investigated.In addition,potential parallels between the J/ψφand J/ψJ/ψsystems,both composed of two vector mesons,are discussed.The continued interest in,and complexity of,these systems underscore the necessity of further experimental exploration with increased statistical precision across a variety of experiments,particularly those with relatively flat efficiency across the Dalitz plot.The J/ψω,φφ,ρω,andρφsystems are mentioned,and the prospects for the J/ψγandγγsystems,are also highlighted.
基金supported by the National SKA Program of China(No.2020SKA0120300)NSFC(12133004)。
文摘We present an analytical treatment of the pulsar radio emission height as a function of phase based on a set of simplifying assumptions.Assuming a dipole field geometry,the emission height can be expressed as a function of phase and the impact angle.We found that:(1)The emission height is a quadratic function of the phase,given the magnetospheric geometry.The emission height is higher at the edge of the pulse profile than at the center.(2)The emission height is also a quadratic function of the impact angle.This point can be compared directly with the observations of the geodetic precessing pulsar PSR J1906+0746.(3)A larger inclination angle may imply a higher emission height,when other parameters are similar.(4)By assuming curvature radiation,or inverse Compton scattering,the Lorentz factor of the radio emitting particles can be obtained as a function of phase.
