Finding pulsars in binaries is important for measurements of the masses of neutron stars(NSs),for tests of gravity theories,and for studies of star evolution.We are carrying out the Galactic Plane Pulsar Snapshot surv...Finding pulsars in binaries is important for measurements of the masses of neutron stars(NSs),for tests of gravity theories,and for studies of star evolution.We are carrying out the Galactic Plane Pulsar Snapshot survey(GPPS)by using the Five-hundred-meter Aperture Spherical radio Telescope(FAST).Here we present the Keplerian parameters for 116 newly discovered pulsars in the FAST GPPS survey and obtain timing solutions for 29 pulsars.Companions of these pulsars are He white dwarfs(WDs),CO/ONe WDs,NSs,main sequence stars and ultra light objects or even planets.Our observations uncover eclipses of eight binary systems.The optical counterpart for the companion of PSR J1908+1036 is identified.The Post-Keplerian parameter w for the double NS systems PSR J0528+3529 and J1844-0128 have been measured,with which the total masses of the binary systems are determined.展开更多
Binary millisecond pulsars with a massive white dwarf(WD)companion are intermediate-mass binary pulsars(IMBPs).They are formed via the Case BB Roche-lobe overflow evolution channel if they are in compact orbits with a...Binary millisecond pulsars with a massive white dwarf(WD)companion are intermediate-mass binary pulsars(IMBPs).They are formed via the Case BB Roche-lobe overflow evolution channel if they are in compact orbits with an orbital period of less than 1 day.They are fairly rare in the known pulsar population;only five such IMBPs have been discovered before,and one of them is in a globular cluster.Here we report six IMBPs in compact orbits:PSRs J0416+5201,J0520+3722,J1919+1341,J1943+2210,J1947+2304 and J2023+2853,discovered during the Galactic Plane Pulsar Snapshot survey by using the Five-hundred-meter Aperture Spherical radio Telescope,doubling the number of such IMBPs due to the high survey sensitivity in the short survey time of 5 minutes.Follow-up timing observations show that they all have either a CO WD or an ONeMg WD companion with a mass greater than about 0.8M_(⊙)in a very circular orbit with an eccentricity in the order of10^(−5).PSR J0416+5201 should be an ONeMg WD companion with a remarkable minimum mass of 1.28M_(⊙).These massive WD companions lead to a detectable Shapiro delay for PSRs J0416+5201,J0520+3722,J1943+2210,and J2023+2853,indicating that their orbits are highly inclined.From the measurement of the Shapiro delay,the pulsar mass of J1943+2210 was constrained to be 1.84^(+0.11)_(-0.09)M_(⊙),and that of PSR J2023+2853 to be 1.28^(+0.06)_(-0.05)M_(⊙).展开更多
The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the most sensitive telescope at the L-band(1.0-1.5 GHz)and has been used to carry out the FAST Galactic Plane Pulsar Snapshot(GPPS)survey in the last 5...The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the most sensitive telescope at the L-band(1.0-1.5 GHz)and has been used to carry out the FAST Galactic Plane Pulsar Snapshot(GPPS)survey in the last 5 yr.Up to now,the survey has covered one-fourth of the planned areas within±10o from the Galactic plane visible by FAST,and discovered 751 pulsars.After the first publication of the discovery of 201 pulsars and one rotating radio transient(RRAT)in 2021 and 76 RRATs in 2023,here we report the discovery of 473 new pulsars from the FAST GPPS survey,including 137 new millisecond pulsars and 30 new RRATs.We find 34 millisecond pulsars discovered by the GPPS survey which can be timed with a precision better than 3μs by using FAST 15 minute observations and can be used for pulsar timing arrays.The GPPS survey has discovered eight pulsars with periods greater than 10 s including one with 29.77 s.The integrated profiles of pulsars and individual pulses of RRATs are presented.During the FAST GPPS survey,we also detected previously known pulsars and updated parameters for 52 pulsars.In addition,we discovered two fast radio bursts plus one probable case with high dispersion measures indicating their extragalactic origin.展开更多
Intensive power ultrasound is introduced to Zr46.75Cu46.75Al6.5bulk metallic glass(BMG)as an easy-procurable,non-destructive physical method to modulate its atomic rearrangement and shear deformation behavior.The micr...Intensive power ultrasound is introduced to Zr46.75Cu46.75Al6.5bulk metallic glass(BMG)as an easy-procurable,non-destructive physical method to modulate its atomic rearrangement and shear deformation behavior.The microstructure after ultrasonic excitation with amplitude about 15μm in 20 k Hz for 2 h is characterized by large amount of Cu10Zr7 nanocrystals with size of 20–50 nm embedded in the glass matrix.This leads to a sharp increase in the critical stress for the first pop-in event of shear banding,and thus simultaneously improves both compressive plasticity and yield strength.Our findings provide a novel approach for overcoming the strength-ductility trade-off dilemma.展开更多
The deformation accompanied by austenite to martensite trans-formation was first studied in Fe-Ni alloys,high-Mn steels,and austenitic stainless steels with a full austenite microstructure.The plasticity of these stee...The deformation accompanied by austenite to martensite trans-formation was first studied in Fe-Ni alloys,high-Mn steels,and austenitic stainless steels with a full austenite microstructure.The plasticity of these steels can be improved by the trans-formation during deformation and hence they were named as transformation-induced plasticity(TRIP)steels[1].Over the past few decades,a series of TRIP steels with multiphase microstructure for automotive applications were developed.These steels contain-ing a certain amount of austenite were called TRIP-assisted steels,such as low-alloy TRIP steels[2],carbide-free bainitic steels[3],δ-TRIP steels[4],quenching and partitioning steels[5],and medium-Mn steels[6].The mechanical property of TRIP steels is largely determined by the mechanical stability of austenite[7]which de-pends on the chemical composition[8],grain size[9],orientation[10],and morphology[11]of austenite grains,as well as the nature of neighboring phases[12].In most cases of TRIP-assisted steels,larger austenite grains transform to martensite earlier or faster than smaller austenite grains with the increase of macrostrain[13-18],indicating lower mechanical stability.However,larger austen-ite grains usually contain less C and Mn[13,17-19]and suffer more strain than smaller grains during deformation[20],it doesn’t mean that grain refinement increases the mechanical stability of austen-ite.展开更多
To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are g...To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are generated by a laser irradiation method.The optimal ZnIn_(2)S_(4)/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g,which is relatively high among the ZnIn_(2)S_(4)-based photocatalysts with-out noble metals.This enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur vacancies.The strong electron coupling effect,which is verified by density functional the-ory(DFT)calculations,impels the photo-generated electrons transfer from CdTe to ZnIn_(2)S_(4),boosting the charge separation.Meanwhile,the sulfur vacancies existing in ZnIn_(2)S_(4) can capture photoelectrons and act as active sites,facilitating the H_(2) generation reaction.In addition,the ZnIn_(2)S_(4) base and the ZnIn_(2)S_(4)/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena,enhancing the photocatalytic performance.This research provides new insights into the regulation of charge transfer through embedding nanocrystals.展开更多
Relativistic electron beams driven by laser wakefield acceleration were utilized to produce ultrashort neutron sources.The experiment was carried out on the 38 fs,~0.5 J,800 nm Ti:Sapphire laser in the 10 TW UT 3 lase...Relativistic electron beams driven by laser wakefield acceleration were utilized to produce ultrashort neutron sources.The experiment was carried out on the 38 fs,~0.5 J,800 nm Ti:Sapphire laser in the 10 TW UT 3 laser lab at University of Texas at Austin.The target gas was a high density pulsed gas jet composed of 90%He and 10%N 2.The laser pulse with a peak intensity of 1.5×10^(18) W/cm^(2) interacted with the target to create a cylindrical plasma channel of 60 mm radius(FWHM)and 1.5 mm length(FWHM).Electron beams of~80 pC with the Gaussian energy distribution centered at 37 MeV and a width of 30 MeV(FWHM)were produced via laser wakefield acceleration.Neutron fluences of~2.4×10^(6) per shot with hundreds of ps temporal length were generated through bremsstrahlung and subsequent photoneutron reactions in a 26.6 mm thick tungsten converter.Results were compared with those of simulations using EPOCH and GEANT4,showing agreement in electron spectrum,neutron fluence,neutron angular distribution and conversion rate.展开更多
The cooling channel process is a rehocasting method by which the prematerial with globular microstructure can be produced to fit the thixocasting process.A three-phase model based on volume averaging approach is propo...The cooling channel process is a rehocasting method by which the prematerial with globular microstructure can be produced to fit the thixocasting process.A three-phase model based on volume averaging approach is proposed to simulate the cooling channel process of A356 Aluminum alloy.The three phases are liquid,solid and air respectively and treated as separated and interacting continua,sharing a single pressure field.The mass,momentum,enthalpy transport equations for each phase are solved.The developed model can predict the evolution of liquid,solid and air fraction as well as the distribution of grain density and grain size.The effect of pouring temperature on the grain density,grain size and solid fraction is analyzed in detail.展开更多
Pulsar polarization profiles form a very basic database for understanding the emission processes in a pulsar magnetosphere.After careful polarization calibration of the 19-beam L-band receiver and verification of beam...Pulsar polarization profiles form a very basic database for understanding the emission processes in a pulsar magnetosphere.After careful polarization calibration of the 19-beam L-band receiver and verification of beamoffset observation results,we obtain polarization profiles of 682 pulsars from observations by the Five-hundredmeter Aperture Spherical radio Telescope(FAST)duringthe Galactic Plane Pulsar Snapshot survey and other normal FAST projects.Among them,polarization profiles of about 460 pulsars are observed for the first time.The profiles exhibit diverse features.Some pulsars have a polarization position angle curve with a good S-shaped swing,some with orthogonal modes;some have components with highly linearly polarized components or strong circularly polarized components;some have a very wide profile,coming from an aligned rotator,and some have an interpulse from a perpendicular rotator;some wide profiles are caused by interstellar scattering.We derive geometric parameters for 190 pulsars from the S-shaped position angle curves or with orthogonal modes.We find that the linear and circular polarization or the widths of pulse profiles have various frequency dependencies.Pulsars with a large fraction of linear polarization are more likely to have a large Edot.展开更多
FeGa thin film has been deposited on（100）-oriented GaAs and（001）-oriented Si substrates with different film thicknesses and laser energy densities at room temperature by pulsed laser deposition system.Materials st...FeGa thin film has been deposited on（100）-oriented GaAs and（001）-oriented Si substrates with different film thicknesses and laser energy densities at room temperature by pulsed laser deposition system.Materials structure and static magnetic of FeGa film have great changes depending on the substrate and energy density of pulsed laser.X-ray diffraction reveals the presence of first-order order–disorder structure ofgrain phase and disordered bcc A2 structure on GaAs substrate.The coercivity and remanence of FeGa film on GaAs substrate ratio show a regular dependence on the thickness and energy densities.However,film on Si substrate did not exhibit structure change,which can be attributed to a large lattice mismatch between FeGa and Si.展开更多
By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0...By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) events.The mass of χ_(c 0) is determined to be M (χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c^(2),and its full width is F (χ_(c 0))=(12.52±0.12±0.13)MeV,where the first uncertainty is statistical,the second systematic,and the third for mass comes from χ_(c 2) mass uncertainty.These measurements improve the precision of χ_(c 0) mass by a factor of four and width by one order of magnitude over the previous individual measurements,and significantly boost our knowledge about the charmonium spectrum.Together with additional (345.4±2.6)×10^(6)(3686) data events taken in 2012,the decay branching fractions of χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) are measured as well,with precision improved by a factor of three compared to previous measurements.These χ_(c 0) decay branching fractions provide important inputs for the study of glueballs.展开更多
Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limi...Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limit on its partial branching fraction for photon energies E_(γ)>10 MeV was determined to be 1.2×10^(-5)at a 90%confidence level;this excludes most current theoretical predictions.A sophisticated deep learning approach,which includes thorough validation and is based on the Transformer architecture,was implemented to efficiently distinguish the signal from massive backgrounds.展开更多
Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation de...Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation decayφ→π^(+)π^(+)e^(-)e^(-)via J/ψ→φη.No obviously signals are found.The upper limit on the branching fraction ofφ→π^(+)π^(+)e^(-)e^(-)is set to be 1.3×10^(-5)at the 90%confidence level.展开更多
Based on a sample of 2.7x 10^(9)ψ(3686)events collected by the BESIII detector operating at the BEP-CII collider,the decay 4(3686)→YX_(cJ),X_(cJ)→ηηη’is analyzed.The decay modes X_(c1)and X_(c2)→ηηη’are ob...Based on a sample of 2.7x 10^(9)ψ(3686)events collected by the BESIII detector operating at the BEP-CII collider,the decay 4(3686)→YX_(cJ),X_(cJ)→ηηη’is analyzed.The decay modes X_(c1)and X_(c2)→ηηη’are observed for the first time,and their corresponding branching fractions are determined to be B(X_(c1)→ηηη’)=(1.40±0.13(stat.)±0.09(sys.))×10^(-4)and B(X_(c2)→ηηη’)=(4.18±0.84(stat.)±0.48(sys.))×10^(-5).An upper limit on the branching fraction of x_(co)→ηηη’is set as 2.59×10^(-5)at a 90%confidence level(CL).A partial wave analys-is(PWA)of the decay X_(c1)→ηηη’is performed to search for the 1^(-+)exotic stateη1(1855).The PWA result indic-ates that the structure in theηη’mass spectrum is attributed to f_(0)(1500),while in the m mass spectrum,it is attrib-uted to the 0^(++)phase space.The upper limit of B(x_(cl)→η1(1855)η)·B(η1(1855)→ηη')<9.79×10^(-5)is set based on the PWA at 90%CL.展开更多
Lepton number violation decayω→π^(+)π^(+)e^(-)e^(-)+c.c.is searched for via J/ψ→ωηusing a data sample of(1.0087±0.0044)×10^(10)J/ψevents collected via the BESIII detector at the BEPCII collider.No s...Lepton number violation decayω→π^(+)π^(+)e^(-)e^(-)+c.c.is searched for via J/ψ→ωηusing a data sample of(1.0087±0.0044)×10^(10)J/ψevents collected via the BESIII detector at the BEPCII collider.No significant signal is observed,and the upper limit on the branching fraction ofω→π^(+)π^(+)e^(-)e^(-)+c.c.at the 90%confidence level is determined for the first time to be 2.8×10^(-6).展开更多
We search for the leptonic decay D^(+)→e^(+)ν_(e)using an e+e-collision data sample with an integrated luminosity of 20.3 fb-1collected with the BESIII detector at a center-of-mass energy of 3.773 GeV.Significant si...We search for the leptonic decay D^(+)→e^(+)ν_(e)using an e+e-collision data sample with an integrated luminosity of 20.3 fb-1collected with the BESIII detector at a center-of-mass energy of 3.773 GeV.Significant signal is not observed,and an upper limit on the branching fraction of D^(+)→e^(+)ν_(e)is set as 9.7×10^(-7),at a confidence level of 90%.Our upper limit is an order of magnitude smaller than the previous limit for this decay mode.展开更多
Utilizing 4.5 fb^(-1)ofe^(+)e^(-)annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider,we searched for singly Cabibbo-suppressed h...Utilizing 4.5 fb^(-1)ofe^(+)e^(-)annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider,we searched for singly Cabibbo-suppressed hadronic decaysΛ_(c)^(+)→Σ^(0)K^(+)π^(0)andΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−)and with a single-tag method.No significant signals were observed for both decays.The upper limits on the branching fractions at the 90%confidence level were determined to be 5.0×10^(-4)for and forΛ_(c)^(+)→Σ^(0)K^(+)π^(0)and 6.5×10^(-4)forΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−).展开更多
Based on(10087±44)×10^(6) J/ψevents collected with the BESⅢdetector,we search for the lepton number violating decay J/ψ→K^(+)K^(+)e^(-)e^(-)+c.c.for the first time.The upper limit on the branching fracti...Based on(10087±44)×10^(6) J/ψevents collected with the BESⅢdetector,we search for the lepton number violating decay J/ψ→K^(+)K^(+)e^(-)e^(-)+c.c.for the first time.The upper limit on the branching fraction of this decay is set to 2.1×10^(-9)at the 90%confidence level with a frequentist method.This is the first search for J/ψdecays with a lepton number change by two,offering valuable insights into the underlying physical processes.展开更多
The coarsening kinetics of a two-phase mixture with a large diffusional mobility disparity between the two phases is studied using a variable-mobility Cahn Hilliard equation.The semi-implicit spectral numerical techni...The coarsening kinetics of a two-phase mixture with a large diffusional mobility disparity between the two phases is studied using a variable-mobility Cahn Hilliard equation.The semi-implicit spectral numerical technique was employed,and a number of interpolation functions are considered for describing the change in diffusion mobility across the interface boundary from one phase to another.The coarsening rate of domain size was measured using both structure and pair correlation functions as well as the direct computation of particle sizes in real space for the case that the coarsening phase consists of dispersed particles.We discovered that the average size(R)versus time(t)follows the R^(10/3)∝t law,in contrast to the conventional LSW theory,R^(3)∝t,and the interface-diffusion dominated two-phase coarsening,R^(4)∝t.展开更多
Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays...Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D^(0)→a_(1)(1260)π,D^(0)→π(1300)π,D^(0)→ρ(770)ρ(770),and D^(0)→2(ππ)_(S)are observed in both channels.With the obtained amplitude model,the CP-even fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are determined to be(75.2±1.1_(stat).±1.5_(syst.))%and(68.9±1.5_(stat).±2.4_(syst.))%,respectively.The branching fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are measured to be(0.688±0.010_(stat.)±0.010_(syst.))%and(0.951±0.025_(stat.)±0.021_(syst.))%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D^(0)→4πwhen used to determine the CKM angleγ(ϕ_(3))via the B^(−)→DK^(−)decay.展开更多
基金supported by the National SKA program of China(No.2020SKA0120200)the National Natural Science Foundation of China(No.12133004)+1 种基金the Chinese Academy of Science(No.JZHKYPT-2021-06)and the National Key R&D Program of China(No.2021YFA1600401 and 2021YFA1600400)supported by the National Natural Science Foundation of China(No.11988101,12133004 and 11833009).
文摘Finding pulsars in binaries is important for measurements of the masses of neutron stars(NSs),for tests of gravity theories,and for studies of star evolution.We are carrying out the Galactic Plane Pulsar Snapshot survey(GPPS)by using the Five-hundred-meter Aperture Spherical radio Telescope(FAST).Here we present the Keplerian parameters for 116 newly discovered pulsars in the FAST GPPS survey and obtain timing solutions for 29 pulsars.Companions of these pulsars are He white dwarfs(WDs),CO/ONe WDs,NSs,main sequence stars and ultra light objects or even planets.Our observations uncover eclipses of eight binary systems.The optical counterpart for the companion of PSR J1908+1036 is identified.The Post-Keplerian parameter w for the double NS systems PSR J0528+3529 and J1844-0128 have been measured,with which the total masses of the binary systems are determined.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11988101,12133004 and 11833009)the Research Program of the Chinese Academy of Sciences(grant No.QYZDJ-SSW-SLH021 and JZHKYPT-2021-06).
文摘Binary millisecond pulsars with a massive white dwarf(WD)companion are intermediate-mass binary pulsars(IMBPs).They are formed via the Case BB Roche-lobe overflow evolution channel if they are in compact orbits with an orbital period of less than 1 day.They are fairly rare in the known pulsar population;only five such IMBPs have been discovered before,and one of them is in a globular cluster.Here we report six IMBPs in compact orbits:PSRs J0416+5201,J0520+3722,J1919+1341,J1943+2210,J1947+2304 and J2023+2853,discovered during the Galactic Plane Pulsar Snapshot survey by using the Five-hundred-meter Aperture Spherical radio Telescope,doubling the number of such IMBPs due to the high survey sensitivity in the short survey time of 5 minutes.Follow-up timing observations show that they all have either a CO WD or an ONeMg WD companion with a mass greater than about 0.8M_(⊙)in a very circular orbit with an eccentricity in the order of10^(−5).PSR J0416+5201 should be an ONeMg WD companion with a remarkable minimum mass of 1.28M_(⊙).These massive WD companions lead to a detectable Shapiro delay for PSRs J0416+5201,J0520+3722,J1943+2210,and J2023+2853,indicating that their orbits are highly inclined.From the measurement of the Shapiro delay,the pulsar mass of J1943+2210 was constrained to be 1.84^(+0.11)_(-0.09)M_(⊙),and that of PSR J2023+2853 to be 1.28^(+0.06)_(-0.05)M_(⊙).
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11988101,12133004 and 11833009)also the National SKA Program of China 2020SKA0120100The pulsar searching team is specially supported by the Chinese Academy of Sciences via the project JZHKYPT-2021-06.
文摘The Five-hundred-meter Aperture Spherical radio Telescope(FAST)is the most sensitive telescope at the L-band(1.0-1.5 GHz)and has been used to carry out the FAST Galactic Plane Pulsar Snapshot(GPPS)survey in the last 5 yr.Up to now,the survey has covered one-fourth of the planned areas within±10o from the Galactic plane visible by FAST,and discovered 751 pulsars.After the first publication of the discovery of 201 pulsars and one rotating radio transient(RRAT)in 2021 and 76 RRATs in 2023,here we report the discovery of 473 new pulsars from the FAST GPPS survey,including 137 new millisecond pulsars and 30 new RRATs.We find 34 millisecond pulsars discovered by the GPPS survey which can be timed with a precision better than 3μs by using FAST 15 minute observations and can be used for pulsar timing arrays.The GPPS survey has discovered eight pulsars with periods greater than 10 s including one with 29.77 s.The integrated profiles of pulsars and individual pulses of RRATs are presented.During the FAST GPPS survey,we also detected previously known pulsars and updated parameters for 52 pulsars.In addition,we discovered two fast radio bursts plus one probable case with high dispersion measures indicating their extragalactic origin.
基金the National Natural Science Foundation of China(Nos.51727803,51922089 and 51972275)the Key Research Plan in Shanxi Province(No.2018GY-104)。
文摘Intensive power ultrasound is introduced to Zr46.75Cu46.75Al6.5bulk metallic glass(BMG)as an easy-procurable,non-destructive physical method to modulate its atomic rearrangement and shear deformation behavior.The microstructure after ultrasonic excitation with amplitude about 15μm in 20 k Hz for 2 h is characterized by large amount of Cu10Zr7 nanocrystals with size of 20–50 nm embedded in the glass matrix.This leads to a sharp increase in the critical stress for the first pop-in event of shear banding,and thus simultaneously improves both compressive plasticity and yield strength.Our findings provide a novel approach for overcoming the strength-ductility trade-off dilemma.
基金supported by the National Natural Science Foundation(No.52101128)the National Key R&D Program(No.2018YFE0306102)+1 种基金the Postdoctoral Science Foundation(No.2022M710021)the Northeastern University Postdoctoral Research Fund of China(No.20220202).
文摘The deformation accompanied by austenite to martensite trans-formation was first studied in Fe-Ni alloys,high-Mn steels,and austenitic stainless steels with a full austenite microstructure.The plasticity of these steels can be improved by the trans-formation during deformation and hence they were named as transformation-induced plasticity(TRIP)steels[1].Over the past few decades,a series of TRIP steels with multiphase microstructure for automotive applications were developed.These steels contain-ing a certain amount of austenite were called TRIP-assisted steels,such as low-alloy TRIP steels[2],carbide-free bainitic steels[3],δ-TRIP steels[4],quenching and partitioning steels[5],and medium-Mn steels[6].The mechanical property of TRIP steels is largely determined by the mechanical stability of austenite[7]which de-pends on the chemical composition[8],grain size[9],orientation[10],and morphology[11]of austenite grains,as well as the nature of neighboring phases[12].In most cases of TRIP-assisted steels,larger austenite grains transform to martensite earlier or faster than smaller austenite grains with the increase of macrostrain[13-18],indicating lower mechanical stability.However,larger austen-ite grains usually contain less C and Mn[13,17-19]and suffer more strain than smaller grains during deformation[20],it doesn’t mean that grain refinement increases the mechanical stability of austen-ite.
基金The research was sponsored by the National Natural Science Foundation of China(Nos.52172101 and 51872240)the National Key R&D Program for International Cooperation(No.2021YFE0115100)+2 种基金Shaanxi Province Key Research and Develop-ment Program(No.2021ZDLGY14-08)the Fundamental Research Funds for the Central Universities(No.3102019JC005)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110228).The authors thank the Analysis and Test Center of Northwestern Polytechnical University and Shaanxi Materials Analysis and Research Center for XPS,SEM,and TEM characterizations.
文摘To suppress the inner charge recombination and inject vast electrons,CdTe nanocrystals are embedded into ultrathin ZnIn_(2)S_(4) nanosheets to construct ZnIn_(2)S_(4)/CdTe heterostructures,where the nanocrystals are generated by a laser irradiation method.The optimal ZnIn_(2)S_(4)/CdTe heterojunction exhibits an excellent catalytic activity of 24.3 mmol/h/g,which is relatively high among the ZnIn_(2)S_(4)-based photocatalysts with-out noble metals.This enhancement is ascribed to a win-win mechanism of nanoscale heterojunctions and sulfur vacancies.The strong electron coupling effect,which is verified by density functional the-ory(DFT)calculations,impels the photo-generated electrons transfer from CdTe to ZnIn_(2)S_(4),boosting the charge separation.Meanwhile,the sulfur vacancies existing in ZnIn_(2)S_(4) can capture photoelectrons and act as active sites,facilitating the H_(2) generation reaction.In addition,the ZnIn_(2)S_(4) base and the ZnIn_(2)S_(4)/CdTe heterojunction also possess an evident photothermal effect and renewable cycle phenomena,enhancing the photocatalytic performance.This research provides new insights into the regulation of charge transfer through embedding nanocrystals.
基金This paper is based upon work supported by the Air Force Office of Scientific Research under award number FA9550-14-1-0045The project was also supported by the NNSA coop-erative agreement DE-NA0002008the Defense Advanced Research Projects Agency's PULSE program(12-63-PULSE-FP014).
文摘Relativistic electron beams driven by laser wakefield acceleration were utilized to produce ultrashort neutron sources.The experiment was carried out on the 38 fs,~0.5 J,800 nm Ti:Sapphire laser in the 10 TW UT 3 laser lab at University of Texas at Austin.The target gas was a high density pulsed gas jet composed of 90%He and 10%N 2.The laser pulse with a peak intensity of 1.5×10^(18) W/cm^(2) interacted with the target to create a cylindrical plasma channel of 60 mm radius(FWHM)and 1.5 mm length(FWHM).Electron beams of~80 pC with the Gaussian energy distribution centered at 37 MeV and a width of 30 MeV(FWHM)were produced via laser wakefield acceleration.Neutron fluences of~2.4×10^(6) per shot with hundreds of ps temporal length were generated through bremsstrahlung and subsequent photoneutron reactions in a 26.6 mm thick tungsten converter.Results were compared with those of simulations using EPOCH and GEANT4,showing agreement in electron spectrum,neutron fluence,neutron angular distribution and conversion rate.
文摘The cooling channel process is a rehocasting method by which the prematerial with globular microstructure can be produced to fit the thixocasting process.A three-phase model based on volume averaging approach is proposed to simulate the cooling channel process of A356 Aluminum alloy.The three phases are liquid,solid and air respectively and treated as separated and interacting continua,sharing a single pressure field.The mass,momentum,enthalpy transport equations for each phase are solved.The developed model can predict the evolution of liquid,solid and air fraction as well as the distribution of grain density and grain size.The effect of pouring temperature on the grain density,grain size and solid fraction is analyzed in detail.
基金supported by the National Natural Science Foundation of China(NSFC,grant Nos.11988101 and 11833009),supported by the National Natural Science Foundation of China(NSFC,grant No.U2031115)supported by the National Key R&D Program of China(No.2021YFA1600401 and 2021YFA1600400)+1 种基金National Natural Science Foundation of China(NSFC,grant Nos.11873058 and 12133004)the National SKA program of China(No.2020SKA0120200)。
文摘Pulsar polarization profiles form a very basic database for understanding the emission processes in a pulsar magnetosphere.After careful polarization calibration of the 19-beam L-band receiver and verification of beamoffset observation results,we obtain polarization profiles of 682 pulsars from observations by the Five-hundredmeter Aperture Spherical radio Telescope(FAST)duringthe Galactic Plane Pulsar Snapshot survey and other normal FAST projects.Among them,polarization profiles of about 460 pulsars are observed for the first time.The profiles exhibit diverse features.Some pulsars have a polarization position angle curve with a good S-shaped swing,some with orthogonal modes;some have components with highly linearly polarized components or strong circularly polarized components;some have a very wide profile,coming from an aligned rotator,and some have an interpulse from a perpendicular rotator;some wide profiles are caused by interstellar scattering.We derive geometric parameters for 190 pulsars from the S-shaped position angle curves or with orthogonal modes.We find that the linear and circular polarization or the widths of pulse profiles have various frequency dependencies.Pulsars with a large fraction of linear polarization are more likely to have a large Edot.
基金financially supported by the National Youth Natural Science Foundation (nos. 61601293 and 61404085)the Yangfan Plan of Shanghai Youth Science and Technology Talents (no. 15YF408800)the National Natural Science Foundation of China (nos. 11574214, 61376010)
文摘FeGa thin film has been deposited on（100）-oriented GaAs and（001）-oriented Si substrates with different film thicknesses and laser energy densities at room temperature by pulsed laser deposition system.Materials structure and static magnetic of FeGa film have great changes depending on the substrate and energy density of pulsed laser.X-ray diffraction reveals the presence of first-order order–disorder structure ofgrain phase and disordered bcc A2 structure on GaAs substrate.The coercivity and remanence of FeGa film on GaAs substrate ratio show a regular dependence on the thickness and energy densities.However,film on Si substrate did not exhibit structure change,which can be attributed to a large lattice mismatch between FeGa and Si.
基金Supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400,2023YFA1606000)National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+17 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)100 Talents Program of CAS(ZR2022JQ02,ZR2024QA151)supported by Shandong Provincial Natural Science Foundationsupported by the China Postdoctoral Science Foundation(2023M742100)The Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG(FOR5327,GRK 2149)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076,B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘By analyzing ψ(3686) data sample containing (107.7±0.6)×10^(6) events taken with the BESIII detector at the BEPCII storage ring in 2009,the χ_(c 0) resonance parameters are precisely measured using χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) events.The mass of χ_(c 0) is determined to be M (χ_(c 0))=(3415.63±0.07±0.07±0.07)MeV/c^(2),and its full width is F (χ_(c 0))=(12.52±0.12±0.13)MeV,where the first uncertainty is statistical,the second systematic,and the third for mass comes from χ_(c 2) mass uncertainty.These measurements improve the precision of χ_(c 0) mass by a factor of four and width by one order of magnitude over the previous individual measurements,and significantly boost our knowledge about the charmonium spectrum.Together with additional (345.4±2.6)×10^(6)(3686) data events taken in 2012,the decay branching fractions of χ_(c 0,c 2)→π^(+)π^(−)/K^(+)K^(−) are measured as well,with precision improved by a factor of three compared to previous measurements.These χ_(c 0) decay branching fractions provide important inputs for the study of glueballs.
基金supported in part by National Key R&D Program of China(2020YFA0406400,2023YFA1606000,2020YFA0406300)National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+18 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)CAS(YSBR-101)100 Talents Program of CASCAS Project for Young Scientists in Basic Research(YSBR-117)The Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyAgencia Nacional de Investigación y Desarrollo de Chile(ANID),Chile(ANID PIA/APOYO AFB230003)German Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Using 20.3 fb^(-1)of e^(+)e^(-)annihilation data collected at a center-of-mass energy of 3.773 GeV with the BESⅢdetector,we report on an improved search for the radiative leptonic decay D^(+)→γe^(+)ve.An upper limit on its partial branching fraction for photon energies E_(γ)>10 MeV was determined to be 1.2×10^(-5)at a 90%confidence level;this excludes most current theoretical predictions.A sophisticated deep learning approach,which includes thorough validation and is based on the Transformer architecture,was implemented to efficiently distinguish the signal from massive backgrounds.
基金supported in part by the National Key R&D Program of China(2020YFA0406300,2020YFA0406400)National Natural Science Foundation of China(NSFC)(12035009,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017)+17 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASthe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and Cosmologythe European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement(894790)the German Research Foundation DFG(455635585),the Collaborative Research Center CRC 1044,FOR5327,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF2022R1A2C1092335)National Science and Technology Fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)the Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)the U.S.Department of Energy(DE-FG02-05ER41374).
文摘Using an electron-positron collision data sample corresponding to(1.0087±0.0044)×10^(10)events collected using the BESIII detector at the BEPCII collider,we firstly search for the lepton number violation decayφ→π^(+)π^(+)e^(-)e^(-)via J/ψ→φη.No obviously signals are found.The upper limit on the branching fraction ofφ→π^(+)π^(+)e^(-)e^(-)is set to be 1.3×10^(-5)at the 90%confidence level.
基金National Key R&D Program of China(2023YFA1606000,2023YFA1606704)National Natural Science Foundation of China(NSFC)(11635010,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+14 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramCAS(YSBR-101)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyAgencia Nacional de Investigación y Desarrollo de Chile(ANID),Chile(ANID PIA/APOYO AFB230003)German Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources Institutional Development,Research and Innovation of Thailand(B50G670107)Polish National Science Centre(2024/53/B/ST2/00975)Swedish Research Council(2019.04595)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Based on a sample of 2.7x 10^(9)ψ(3686)events collected by the BESIII detector operating at the BEP-CII collider,the decay 4(3686)→YX_(cJ),X_(cJ)→ηηη’is analyzed.The decay modes X_(c1)and X_(c2)→ηηη’are observed for the first time,and their corresponding branching fractions are determined to be B(X_(c1)→ηηη’)=(1.40±0.13(stat.)±0.09(sys.))×10^(-4)and B(X_(c2)→ηηη’)=(4.18±0.84(stat.)±0.48(sys.))×10^(-5).An upper limit on the branching fraction of x_(co)→ηηη’is set as 2.59×10^(-5)at a 90%confidence level(CL).A partial wave analys-is(PWA)of the decay X_(c1)→ηηη’is performed to search for the 1^(-+)exotic stateη1(1855).The PWA result indic-ates that the structure in theηη’mass spectrum is attributed to f_(0)(1500),while in the m mass spectrum,it is attrib-uted to the 0^(++)phase space.The upper limit of B(x_(cl)→η1(1855)η)·B(η1(1855)→ηη')<9.79×10^(-5)is set based on the PWA at 90%CL.
基金Supported in part by National Key R&D Program of China(2023YFA1606000,2023YFA1606704)National Natural Science Foundation of China(NSFC)(12035009,11875170,11635010,11935015,11935016,11935018,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+16 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Program,CAS(YSBR-101)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)Shanghai Key Laboratory for Particle Physics and CosmologyAgencia Nacional de Investigación y Desarrollo de Chile(ANID)Chile(ANID PIA/APOYO AFB230003)ERC(758462)German Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaPolish National Science Centre(2024/53/B/ST2/00975)STFC(United Kingdom)Swedish Research Council(2019.04595)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Lepton number violation decayω→π^(+)π^(+)e^(-)e^(-)+c.c.is searched for via J/ψ→ωηusing a data sample of(1.0087±0.0044)×10^(10)J/ψevents collected via the BESIII detector at the BEPCII collider.No significant signal is observed,and the upper limit on the branching fraction ofω→π^(+)π^(+)e^(-)e^(-)+c.c.at the 90%confidence level is determined for the first time to be 2.8×10^(-6).
基金Supported in part by the National Key R&D Program of China(2023YFA1606000,2020YFA0406400,2020YFA0406300)the National Natural Science Foundation of China(NSFC)(11635010,11735014,11935015,11935016,11875054,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+12 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)the Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U2032104,U1832207)the 100 Talents Program of CAS,the Excellent Youth Foundation of Henan Scientific Commitee(242300421044)the Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and Cosmology,the German Research Foundation DFG(FOR5327)the Istituto Nazionale di Fisica Nucleare,Italy,the Knut and Alice Wallenberg Foundation(2021.0174,2021.0299)the Ministry of Development of Turkey(DPT2006K-120470),the National Research Foundation of Korea(NRF-2022R1A2C1092335)the National Science and Technology Fund of Mongoliathe National Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research,and Innovation of Thailand(B16F640076,B50G670107)the Polish National Science Center(2019/35/O/ST2/02907)the Swedish Research Council(2019.04595)the Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)the US Department of Energy(DE-FG02-05ER41374)。
文摘We search for the leptonic decay D^(+)→e^(+)ν_(e)using an e+e-collision data sample with an integrated luminosity of 20.3 fb-1collected with the BESIII detector at a center-of-mass energy of 3.773 GeV.Significant signal is not observed,and an upper limit on the branching fraction of D^(+)→e^(+)ν_(e)is set as 9.7×10^(-7),at a confidence level of 90%.Our upper limit is an order of magnitude smaller than the previous limit for this decay mode.
基金supported in part by National Key R&D Program of China(2020YFA0406300,2020YFA0406400,2023YFA1606000)National Natural Science Foundation of China(NSFC)(12205141,11635010,11735014,11935015,11935016,11935018,12025502,12035009,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819)+16 种基金Natural Science Foundation of Hunan Province(2024JJ2044)the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1832207)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG(FOR5327)Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation(2021.0174,2021.0299)Ministry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076,B50G670107)Polish National Science Centre(2019/35/O/ST2/02907)Swedish Research Council(2019.04595)The Swedish Foundation for International Cooperation in Research and Higher Education(CH2018-7756)U.S.Department of Energy(DE-FG02-05ER41374)。
文摘Utilizing 4.5 fb^(-1)ofe^(+)e^(-)annihilation data collected at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV by the BESIII detector at the BEPCII collider,we searched for singly Cabibbo-suppressed hadronic decaysΛ_(c)^(+)→Σ^(0)K^(+)π^(0)andΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−)and with a single-tag method.No significant signals were observed for both decays.The upper limits on the branching fractions at the 90%confidence level were determined to be 5.0×10^(-4)for and forΛ_(c)^(+)→Σ^(0)K^(+)π^(0)and 6.5×10^(-4)forΛ_(c)^(+)→Σ^(0)K^(+)π^(+)π^(−).
基金supported in part by National Key R&D Program of China under Contracts Nos.2023YFA1606000,2023YFA1606704National Natural Science Foundation of China(NSFC)under Contracts Nos.12035009,11635010,11935015,11935016,11935018,12025502,12035013,12061131003,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017,12361141819+15 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramCAS under Contract No.YSBR-101100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)Shanghai Key Laboratory for Particle Physics and CosmologyGerman Research Foundation DFG under Contract No.FOR5327Istituto Nazionale di Fisica Nucleare,ItalyKnut and Alice Wallenberg Foundation under Contracts Nos.2021.0174,2021.0299Ministry of Development of Turkey under Contract No.DPT2006K-120470National Research Foundation of Korea under Contract No.NRF-2022R1A2C1092335National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional DevelopmentResearch and Innovation of Thailand under Contract No.B50G670107Polish National Science Centre under Contract No.2024/53/B/ST2/00975Swedish Research Council under Contract No.2019.04595U.S.Department of Energy under Contract No.DE-FG02-05ER41374。
文摘Based on(10087±44)×10^(6) J/ψevents collected with the BESⅢdetector,we search for the lepton number violating decay J/ψ→K^(+)K^(+)e^(-)e^(-)+c.c.for the first time.The upper limit on the branching fraction of this decay is set to 2.1×10^(-9)at the 90%confidence level with a frequentist method.This is the first search for J/ψdecays with a lepton number change by two,offering valuable insights into the underlying physical processes.
基金the financial supports from the National Science Foundation under the grant number DMR-0710483(Chen)NSF-DMS 0712744(Du)+1 种基金DMR-0510180(Liu)DMR-0710484(K.G.Wang).
文摘The coarsening kinetics of a two-phase mixture with a large diffusional mobility disparity between the two phases is studied using a variable-mobility Cahn Hilliard equation.The semi-implicit spectral numerical technique was employed,and a number of interpolation functions are considered for describing the change in diffusion mobility across the interface boundary from one phase to another.The coarsening rate of domain size was measured using both structure and pair correlation functions as well as the direct computation of particle sizes in real space for the case that the coarsening phase consists of dispersed particles.We discovered that the average size(R)versus time(t)follows the R^(10/3)∝t law,in contrast to the conventional LSW theory,R^(3)∝t,and the interface-diffusion dominated two-phase coarsening,R^(4)∝t.
基金Supported in part by the National Key R&D Program of China(2020YFA0406300,2020YFA0406400)the National Natural Science Foundation of China(NSFC)(11625523,11635010,11735014,11835012,11935015,11935016,11935018,11961141012,12025502,12035009,12035013,12061131003,12105276,12122509,12192260,12192261,12192262,12192263,12192264,12192265,12221005,12225509,12235017)+15 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility Programthe CAS Center for Excellence in Particle Physics(CCEPP)Joint Large-Scale Scientific Facility Funds of the NSFC and CAS(U1732263,U1832103,U1832207,U2032111)CAS Key Research Program of Frontier Sciences(QYZDJ-SSW-SLH003,QYZDJ-SSW-SLH040)100 Talents Program of CASThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyEuropean Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement(894790)German Research Foundation DFG(455635585),Collaborative Research Center CRC 1044,FOR5327,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(DPT2006K-120470)National Research Foundation of Korea(NRF-2022R1A2C1092335)National Science and Technology fund of MongoliaNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation of Thailand(B16F640076)Polish National Science Centre(2019/35/O/ST2/02907)The Swedish Research CouncilU.S.Department of Energy(DE-FG02-05ER41374)。
文摘Using e^(+)e^(−)annihilation data corresponding to an integrated luminosity of 2.93 fb^(−1)taken at the center-of-mass energy√s=3.773 GeV with the BESIII detector,a joint amplitude analysis is performed on the decays D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η).The fit fractions of individual components are obtained,and large interferences among the dominant components of the decays D^(0)→a_(1)(1260)π,D^(0)→π(1300)π,D^(0)→ρ(770)ρ(770),and D^(0)→2(ππ)_(S)are observed in both channels.With the obtained amplitude model,the CP-even fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are determined to be(75.2±1.1_(stat).±1.5_(syst.))%and(68.9±1.5_(stat).±2.4_(syst.))%,respectively.The branching fractions of D^(0)→π^(+)π^(−)π^(+)π^(−)and D^(0)→π^(+)π^(−)π^(0)π^(0)(non-η)are measured to be(0.688±0.010_(stat.)±0.010_(syst.))%and(0.951±0.025_(stat.)±0.021_(syst.))%,respectively.The amplitude analysis provides an important model for the binning strategy in measuring the strong phase parameters of D^(0)→4πwhen used to determine the CKM angleγ(ϕ_(3))via the B^(−)→DK^(−)decay.
