In this paper, we present the exact calculations for the vertex ^-sγb and ^sZb in the unitary gauge. We find that （a） the divergent- and μ-dependent terms are left in the effective vertex function Г^γμ（p, k） ...In this paper, we present the exact calculations for the vertex ^-sγb and ^sZb in the unitary gauge. We find that （a） the divergent- and μ-dependent terms are left in the effective vertex function Г^γμ（p, k） for b → sγ transition even after we sum up the contributions from four related Feynman diagrams; （b） for an on-shell photon, such terms do not contribute et al.; （c） for off-shell photon, these terms will be canceled when the contributions from both vertex ^sγb and ^sZb are taken into account simultaneously, and therefore the finite and gauge-independent function Zo（xt） = Co（xt） ＋ Do（xt）/4, which governs the semi-leptonic decay b → sl^- l^＋, is derived in the unitary gauge.展开更多
【目的】检验SCOPE(Soil Canopy Observation of Photosynthesis and Energy fluxes)模型用于模拟樟子松人工林的日光诱导叶绿素荧光(sun-induced chlorophyll fluorescence,SIF)和植被总初级生产力(gross primary productivity,GPP)动...【目的】检验SCOPE(Soil Canopy Observation of Photosynthesis and Energy fluxes)模型用于模拟樟子松人工林的日光诱导叶绿素荧光(sun-induced chlorophyll fluorescence,SIF)和植被总初级生产力(gross primary productivity,GPP)动态变化的可能性。【方法】对科尔沁沙地南缘樟子松人工林,基于样地SIF、GPP及气象协同观测数据,利用SCOPE模型模拟SIF与GPP的日变化与季节变化,评估了SCOPE模型在典型晴天、典型多云日、整个观测期的模拟效果。【结果】结果显示,利用气象观测数据及冠层参数(入射短波辐射、气温、大气实际水汽压、CO_(2)浓度及叶面积指数),可驱动SCOPE模型模拟樟子松人工林的SIF与GPP。典型晴天日与多云日的SIF模拟值和实测值的R^(2)分别为0.42与0.52,RMSE分别为0.19与0.18 W·m^(-2)·μm^(-1)·sr^(-1);GPP模拟值和观测值的R^(2)分别为0.78与0.89,RMSE分别为1.87与2.57μmol·m^(-2)·s^(-1)。在季节尺度上,SIF和GPP模拟值和观测值的R^(2)分别为0.50、0.72,RMSE分别为0.19 W·m^(-2)·μm^(-1)·sr^(-1)和2.64μmol·m^(-2)·s^(-1)。在整个观测期,多云日的SIF(R^(2)=0.31,RMSE=0.22 W·m^(-2)·μm^(-1)·sr^(-1))与GPP(R^(2)=0.80,RMSE=2.42μmol·m^(-2)·s^(-1))的模拟效果优于晴天日(SIF:R^(2)=0.30,RMSE=0.26 W·m^(-2)·μm^(-1)·sr^(-1),GPP:R^(2)=0.64,RMSE=3.64μmol·m^(-2)·s^(-1))。SIF模拟值总体高于观测值,当SIF强度较低时易对SIF高估,反之则易低估。GPP的模拟精度较高,模型对较低与较高GPP有所低估,对中间值有所高估。【结论】SCOPE模型可用于日尺度与季节尺度的SIF与GPP模拟,且多云日的模拟精度更高。SCOPE模型对樟子松人工林的GPP模拟结果优于SIF,推测SIF模拟精度较低的原因可能是模型对SIF的模拟是基于阔叶植物的辐射传输过程。未来应发展针对针叶植物的SIF辐射传输模型,为针叶林的辐射传输与荧光遥感监测提供模型基础。展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 10575052 and the Specialized Research Fund for the Doctoral Program of Higher Education （SRFDP） under Grant No. 20050319008
文摘In this paper, we present the exact calculations for the vertex ^-sγb and ^sZb in the unitary gauge. We find that （a） the divergent- and μ-dependent terms are left in the effective vertex function Г^γμ（p, k） for b → sγ transition even after we sum up the contributions from four related Feynman diagrams; （b） for an on-shell photon, such terms do not contribute et al.; （c） for off-shell photon, these terms will be canceled when the contributions from both vertex ^sγb and ^sZb are taken into account simultaneously, and therefore the finite and gauge-independent function Zo（xt） = Co（xt） ＋ Do（xt）/4, which governs the semi-leptonic decay b → sl^- l^＋, is derived in the unitary gauge.
基金Project(52308419)supported by the National Natural Science Foundation of ChinaProject(R-5020-18)supported by the Research Grants Council,University Grants Committee of the Hong Kong Special Administrative Region(SAR),China+4 种基金Project(K-BBY1)supported by the Innovation and Technology Commission of the Hong Kong SAR Government,ChinaProject(1-W21Q)supported by the Hong Kong Polytechnic University's Postdoc Matching Fund Scheme,ChinaProject(Major Project,2021-Major-01)supported by Science and Technology Research and Development Program Project of China Railway Group LimitedProject(N2022G031)supported by the Science and Technology Research and Development Program Project of China RailwayProject(Major Project,2022-Key-22)supported by the Science and Technology Research and Development Program Project of China Railway Group Limited。
