Study Of Meson Mass Spectrum And Decay Properties In The Quark Model

The upgrade and rapid development of Beijing Spectrometer Positron Collider,the European Nuclear Center Large Hadron Collider and other experimental equipment in recent years have provided a rare opportunity for the development of hadron spectroscopy.Therefore,the study of hadron spectroscopy is a hot spot in particle physics research.In this work,the object of study is meson.First,with the non-relativistic quark model,we study the mass spectrum of bc,bb,ss and B,Bs meson spectroscopies.The main results are:1.Using the newly measured masses of Bc(1S)and Bc(2S)from the CMS Collaboration and the 1S hyperfine splitting determined from the lattice QCD as constrains,we calculate the Bc mass spectrum up to the 6S multiplet with a nonrelativistic linear potential model.Furthermore,using the wave functions from this model we calculate the radiative transitions between the Bc states within a constituent quark model.For the higher mass Bc states lying above DB threshold,we also evaluate the Okubo-ZweigIizuka(OZI)allowed "wo-body strong decays with tlie 3P0 model.We find that:(?)For the S-wave states,the mass of the newly observed Bc*(2S)state might be determined via the M1 transition Bc*(2S)?Bc? in future experiments.While the higher excited Bc states Bc(31S0)and Bc(33S1)may have large possibilities to be established in the DB*final state.(?)For the P-wave states,the decays of the 2P-wave states,Bc(23P0),Bc(2P1)and Bc(2P1')together with all of the 1P-wave states are governed by the E1 transitions.The B1(23P2)state is just?20 MeV above the DB threshold.It mainly decays into the DB channel with a very narrow width of ??1 MeV,.The predicted masses of 3P-wave states are in the range of(7420,7470)MeV.They are broad states with widths of?200 MeV,and strongly couple to the final state.We also find that the 4P-wave states Bc(43PO),Bc(4P1)and Bc(4P1')with a mass around 7.7 GeV may have relatively narrow widths O(100)MeV,these higher P-wave states might be first observed in their dominant channel.(?)The 1D-wave states mainly decay via the EM transitions.The masses of the 2D and 3D states are predicted to be?7.34 and 7.62 GeV,respectively.Their decays are governed by the strong decay modes,such as DB,DB*,BD*or B*D*which might be useful to search for these missing 2D and 3D states in future experiments.For the 1F-wave states,our study shows that they have a mass of?7.23 GeV,lie between the and B*D mass thresholds.They are narrow states with a width of several MeV t.o several ten MeV,and dominantly decay into DB or B*D channels.To look for the missing 1F-wave Bc states,the DB and B*D final states are worth observing.2.Inspired by the new resonance Y(10750),we calculate the masses and two-body OZI-allowed strong decays of the higher vector bottomonium sates within both screened and linear potential models.We discuss the possibilities of ?(10860)and Y(10750)as mixed states via the S-D mixing.Our results suggest that Y(10750)and T(10860)might be explained as mixed states between 5S-and 4D-wave vector bb states.The Y(10750)and T(10860)resonances may correspond to the mixed states dominated by the 4D-and 5S-wave components,respectively.The mass and the strong decay behaviors of the T(11020)resonance are consistent with the assignment of the ?(6S)state in the potential models.3.For the ss states,we calculate mass spectrum of the strangeonium up to the 3D multiplet within a nonrelativistic linear potential quark model.Furthermore,using the obtained wave functions,we also evaluate the strong decays of the strangeonium states with the 3P0 model.Based on our successful explanations of the well established states?(1020),?(1680),h1(1415),f2'(1525),and ?3(1850),we further discuss the possible assignments of strangeonium-like states from experiments by combining our theoretical results with the observations.Some main conclusions as follows:?).Some isoscalar 0++resonances with mass of?1370 MeV(denoted with f0(1370)by the PDG)observed in the KK and ?? final states may correspond to the 13P0 ss state.?).The f2(2010)listed by the PDG[1]might be a good candidate for the 23P2 ss state.The newly observed 1+-resonance X(2062)in the ?'? mass spectrum of the decay J/?????' at BESIII[4]favors the assignment of the 21P1 ss sta.te.?).The isoscalar scalar 0++state with a mass of M=(2411�17)MeV(denoted with f0(2410))observed in J/??KSKS at BESIII[5]may be a newly observed state different from the f0(2330)resonance listed by the PDG[1].The fo(2410)favors the assignment of the 33Po ss state.?).The broad resonance f2(2150)listed by the PDG[1]can be assigned as the 13F2 ss state.Another relatively narrow 4++ resonance f4(2210)first observed in the reaction K-p?K+K-A by the LASS Collaboration[2]might be an assignment of the 13F4 ss state.v).The new resonance X(2500)observed in J/????? at BESIII[3]may be identified as the 41S0 ss state.?).The possibility of ?(2170)as a candidate for ?(3S)or ?(2D)cannot be excluded.Further observations of the decay mode,and precise measurements of the resonance parameters and branching ratios between the main decay modes for the ?(2170)state are crucial to confirm its nature.4.Stimulated by the exciting progress in experiments,we carry out a combined analysis of the masses,and strong and radiative decay properties of the B and Bsmeson states up to the second orbital excitations.Based on our good descriptions of the mass and decay properties for the low-lying well-established states B1(5721),B2*(5747),Bs1(5830)and Bs2*(5840),we give our quark model classifications for the high mass resonances observed in recent years.It is found that(?)the BJ(5840)resonance may be explained as the low mass mixed state B(|SD>L)via 23S1-13D1 mixing,or interpreted as the 2S-wave state B(21S0).(?)The BJ(5970)resonance may be assigned as the 13D3 state in the B meson family.(?)The narrow structure around 6064 MeV observed in the B+K-mass spectrum at LHCb may be mainly caused by the BsJ(6109)resonance decaying into B*+K-,and favors the assignment of the high mass 1D-wave mixed state Bs(1D'2)with JP=2-.(?)The relatively broader BsJ(6114)structure observed at LHCb may be explained with the mixed state Bs(|SD>H)via 23S1-13D1 mixing.Most of the missing 1P-,1D-,and 2S-wave B-and Bs-meson states have a relatively narrow width,they are most likely to be observed in their dominant decay channels with a larger data sample at LHCb.