The dissociative ionization of Ar dimers is investigated in femtosecond laser fields with intensities from 260 to 1020 TW/cm^(2).The three-dimensional momentum and kinetic-energy release of fragmental ions generated f...The dissociative ionization of Ar dimers is investigated in femtosecond laser fields with intensities from 260 to 1020 TW/cm^(2).The three-dimensional momentum and kinetic-energy release of fragmental ions generated from the channels Ar_(2)^(2+)→Ar^(+)+Ar^(+),Ar_(2)^(3+)→Ar^(2+)+Ar^(+),and Ar_(2)^(4+)→Ar^(2+)+Ar^(2+)were measured with a cold-target recoil-ion momentum spectrometer.It is shown that the laser intensity significantly modulates the kinetic energies and angular distributions of fragmental ions from dissociative double ionization.Laser-induced charge-transfer following one-site double ionization contributes relatively more to the dissociative double ionization at lower laser intensity.The calculation results of a one-dimensional model based on the WKB approximation suggest that the charge transfer is suppressed at higher laser intensity due to the core polarization effect.In addition,double,triple,and quadruple dissociative ionizations of Ar dimers are accompanied by frustrated-tunneling ionization that increases with the laser intensity.展开更多
We report a search for a heavier partner of the recently observed Z_(cs)(3985)^(-) state,denoted as Z_(cs)^('-),in the process e^(+)e^(−)→K^(+)D_(s)^(∗−) D^(∗0 )+ c.c.,based on e^(*)e^(-)collision data collected ...We report a search for a heavier partner of the recently observed Z_(cs)(3985)^(-) state,denoted as Z_(cs)^('-),in the process e^(+)e^(−)→K^(+)D_(s)^(∗−) D^(∗0 )+ c.c.,based on e^(*)e^(-)collision data collected at the center-of-mass energies of √s=4.661,4.682 and 4.699 GeV with the BESIII detector.The Z_(cs)^('-) is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark.A partial-reconstruction technique is used to isolate K^(+)recoil-mass spectra,which are probed for a potential contribution from Z_(cs)^('-)→D_(s)^(∗−) D^(∗0 )+ c.c.We find an excess of Z_(cs)^('-)→D_(s)^(*-)-D^(*0)(c.c.)candidates with a significance of 2.1o,after considering systematic uncertainties,at a mass of(4123.5±0.7_(sat)±4.7_(syst.))MeV/c^(2).As the data set is limited in size,the upper limits are evaluated at the 90%confidence level on the product of the Born cross sections(σ^(Borm))and the branching fraction(B)of Z_(cs)^('-)→D_(s)^(*-)-D^(*0),under different assumptions of the Z_(cs)^('-) mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies.The upper limits of σ^(Born).B are found to be at the level of O(1)pb at each energy.Larger data samples are needed to confirm the Z_(cs)^('-) state and clarify its nature in the coming years.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0307700)the Major Research Project of National Natural Science Foundation of China(Grant No.91850201)+2 种基金the Key Program of the National Natural Science Foundation of China(Grant No.12234020)the NSAF Joint Fund(Grant No.U1830206)the National Natural Science Foundation of China(Grant Nos.11974426,11974425,11774322,12104508,12404331,and12374263)。
文摘The dissociative ionization of Ar dimers is investigated in femtosecond laser fields with intensities from 260 to 1020 TW/cm^(2).The three-dimensional momentum and kinetic-energy release of fragmental ions generated from the channels Ar_(2)^(2+)→Ar^(+)+Ar^(+),Ar_(2)^(3+)→Ar^(2+)+Ar^(+),and Ar_(2)^(4+)→Ar^(2+)+Ar^(2+)were measured with a cold-target recoil-ion momentum spectrometer.It is shown that the laser intensity significantly modulates the kinetic energies and angular distributions of fragmental ions from dissociative double ionization.Laser-induced charge-transfer following one-site double ionization contributes relatively more to the dissociative double ionization at lower laser intensity.The calculation results of a one-dimensional model based on the WKB approximation suggest that the charge transfer is suppressed at higher laser intensity due to the core polarization effect.In addition,double,triple,and quadruple dissociative ionizations of Ar dimers are accompanied by frustrated-tunneling ionization that increases with the laser intensity.
基金Supported in part by National Key R&D Program of China(Grant Nos.2020YFA0406400,2020YFA0406300)National Natural Science Foundation of China(NSFC)(Grant Nos.11635010,11735014,11805086,11835012,11935015,11935016,11935018,11961141012,12022510,12025502,12035009,12035013,12192260,12192261,12192262,12192263,12192264,12192265)+18 种基金the Chinese Academy of Sciences(CAS)Large-Scale Scientific Facility ProgramJoint Large-Scale Scientific Facility Funds of the NSFC and CAS(Grant No.U1832207)the CAS Center for Excellence in Particle Physics(CCEPP)100 Talents Program of CASFundamental Research Funds for the Central Universities,Lanzhou University,University of Chinese Academy of SciencesThe Institute of Nuclear and Particle Physics(INPAC)and Shanghai Key Laboratory for Particle Physics and CosmologyERC(Grant No.758462)European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement(Grant No.894790)German Research Foundation DFG(Grant No.443159800),Collaborative Research Center CRC 1044,GRK 2149Istituto Nazionale di Fisica Nucleare,ItalyMinistry of Development of Turkey(Grant No.DPT2006K-120470)National Science and Technology fundNational Science Research and Innovation Fund(NSRF)via the Program Management Unit for Human Resources&Institutional Development,Research and Innovation(Grant No.B16F640076)Olle Engkvist Foundation(Grant No.200-0605)STFC(United Kingdom)Suranaree University of Technology(SUT),Thailand Science Research and Innovation(TSRI),and National Science Research and Innovation Fund(NSRF)(Grant No.160355)The Royal Society,UK(Grant Nos.DH140054,DH160214)The Swedish Research CouncilU.S.Department of Energy(Grant No.DE-FG02-05ER41374)。
文摘We report a search for a heavier partner of the recently observed Z_(cs)(3985)^(-) state,denoted as Z_(cs)^('-),in the process e^(+)e^(−)→K^(+)D_(s)^(∗−) D^(∗0 )+ c.c.,based on e^(*)e^(-)collision data collected at the center-of-mass energies of √s=4.661,4.682 and 4.699 GeV with the BESIII detector.The Z_(cs)^('-) is of interest as it is expected to be a candidate for a hidden-charm and open-strange tetraquark.A partial-reconstruction technique is used to isolate K^(+)recoil-mass spectra,which are probed for a potential contribution from Z_(cs)^('-)→D_(s)^(∗−) D^(∗0 )+ c.c.We find an excess of Z_(cs)^('-)→D_(s)^(*-)-D^(*0)(c.c.)candidates with a significance of 2.1o,after considering systematic uncertainties,at a mass of(4123.5±0.7_(sat)±4.7_(syst.))MeV/c^(2).As the data set is limited in size,the upper limits are evaluated at the 90%confidence level on the product of the Born cross sections(σ^(Borm))and the branching fraction(B)of Z_(cs)^('-)→D_(s)^(*-)-D^(*0),under different assumptions of the Z_(cs)^('-) mass from 4.120 to 4.140 MeV and of the width from 10 to 50 MeV at the three center-of-mass energies.The upper limits of σ^(Born).B are found to be at the level of O(1)pb at each energy.Larger data samples are needed to confirm the Z_(cs)^('-) state and clarify its nature in the coming years.
