Considering the constraints on the scalar leptoqaark(SLQ)free parameters from low energy precision measurement data,the correction effects of the SLQs on the rare decaysΛ_(b)→Al^(+)l^(-)with l=e,μandτwere investig...Considering the constraints on the scalar leptoqaark(SLQ)free parameters from low energy precision measurement data,the correction effects of the SLQs on the rare decaysΛ_(b)→Al^(+)l^(-)with l=e,μandτwere investigated.It was found that,for the decayΛ_(b)→Λ_(e)^(+)e^(-),since the constraints given by the current experimental data on the combination coupling|λ^(31)λ^(21*)I/M^(2)_(LQ)is very loose,the contributions of the SLQs toΛ_(b)→Λ_(e)^(+)e^(-)are too large.If the branching ratio Br(Λ_(b)→Aμ^(+)μ^(-))can be precisely measured at the LHCb in near future,the indirect signals of the SLQs might be observed at the LHCb.展开更多
In this contribution,the α preformation factors of 606 nuclei are extracted within the framework of the generalized liquid drop model(GLDM).Through the systematic analysis of the α preformation factors of even-even ...In this contribution,the α preformation factors of 606 nuclei are extracted within the framework of the generalized liquid drop model(GLDM).Through the systematic analysis of the α preformation factors of even-even Po-U isotopes,we found that there is a significant weakening of influence of N=126 shell closure in uranium,which is consistent with the results of a recent experiment [J.Khuyagbaatar et al.,Phys.Rev.Lett.115,242502(2015)],implying that N=126 may not be the magic number for U isotopes.Furthermore,we propose an improved formula with only 7 parameters to calculate α preformation factors suitable for all types of α-decay;it has fewer parameters than the original formula proposed by Zhang et al.[H.F.Zhang et al.,Phys.Rev.C 80,057301(2009)]with higher precision.The standard deviation of the α preformation factors calculated by our formula with extracted values for all 606 nuclei is 0.365 with a factor of 2.3,indicating that our improved formula can accurately reproduce the α preformation factors.Encouraged by this,the α-decay half-lives of actinide elements are predicted,which could be useful in future experiments.Notably,the predicted α-decay half-lives of two new isotopes 220 Np [Z.Y.Zhang,et al.,Phys.Rev.Lett.122,192503(2019)] and 219 Np [H.B.Yang et al.,Phys.Lett.B 777,212(2018)] are in good agreement with the experimental α-decay half-lives.展开更多
基金National Natural Science Foundation of China(112750088)
文摘Considering the constraints on the scalar leptoqaark(SLQ)free parameters from low energy precision measurement data,the correction effects of the SLQs on the rare decaysΛ_(b)→Al^(+)l^(-)with l=e,μandτwere investigated.It was found that,for the decayΛ_(b)→Λ_(e)^(+)e^(-),since the constraints given by the current experimental data on the combination coupling|λ^(31)λ^(21*)I/M^(2)_(LQ)is very loose,the contributions of the SLQs toΛ_(b)→Λ_(e)^(+)e^(-)are too large.If the branching ratio Br(Λ_(b)→Aμ^(+)μ^(-))can be precisely measured at the LHCb in near future,the indirect signals of the SLQs might be observed at the LHCb.
基金Supported by the National Natural Science Foundation of China (11675066, 11665019, 11947229)Fundamental Research Funds for the Central Universities(lzujbky-2017-ot04)Feitian Scholar Project of Gansu province。
文摘In this contribution,the α preformation factors of 606 nuclei are extracted within the framework of the generalized liquid drop model(GLDM).Through the systematic analysis of the α preformation factors of even-even Po-U isotopes,we found that there is a significant weakening of influence of N=126 shell closure in uranium,which is consistent with the results of a recent experiment [J.Khuyagbaatar et al.,Phys.Rev.Lett.115,242502(2015)],implying that N=126 may not be the magic number for U isotopes.Furthermore,we propose an improved formula with only 7 parameters to calculate α preformation factors suitable for all types of α-decay;it has fewer parameters than the original formula proposed by Zhang et al.[H.F.Zhang et al.,Phys.Rev.C 80,057301(2009)]with higher precision.The standard deviation of the α preformation factors calculated by our formula with extracted values for all 606 nuclei is 0.365 with a factor of 2.3,indicating that our improved formula can accurately reproduce the α preformation factors.Encouraged by this,the α-decay half-lives of actinide elements are predicted,which could be useful in future experiments.Notably,the predicted α-decay half-lives of two new isotopes 220 Np [Z.Y.Zhang,et al.,Phys.Rev.Lett.122,192503(2019)] and 219 Np [H.B.Yang et al.,Phys.Lett.B 777,212(2018)] are in good agreement with the experimental α-decay half-lives.
