I present estimates of the branching fractions in the non-leptonic charmonium two-body decay rates for $B^0\rightarrow ψ(2S)π^0$ decay and the same decays of $B^+\rightarrow ψ(2S)π^+$, $B^0\rightarrow ψ(2S)K^0$ and $B^+\rightarrow ψ(2S)K^+$. These estimates are based on a generalized factorization approach making use of leading order (LO) and next-to-leading order (NLO) contributions. I find that when the large enhancements from the known NLO contributions by using the QCD factorization approach are taken into account, the branching ratios are the following: $Br(B^0\rightarrow ψ(2S)π^0)=(1.067\pm0.059)\times10^{-5}$, $Br(B^+\rightarrow ψ(2S)π^+)=(2.134\pm0.0.118)\times10^{-5}$, $Br(B^0\rightarrow ψ(2S)K^0)=(6.344\pm0.376)\times10^{-4}$ and $Br(B^+\rightarrow ψ(2S)K^+)=(6.344\pm0.376)\times10^{-4}$, while the experimental results are $(1.17\pm 0.17)\times 10^{-5}$, $(2.44\pm 0.30)\times 10^{-5}$, $(6.20\pm 0.50)\times 10^{-4}$ and $(6.39\pm 0.33)\times 10^{-4}$ respectively. All estimates are in good agreement with the experimental results.
$b \to s l \bar l $ in the minimal supergravity model
详细研究了最小超引力模型中的$b \rightarrow s l^+ l^-$过程。考虑到$c\overline{c}$共振的长距离贡献,我们计算了该模型的分支比和轻子前后不对称性。我们发现,有一个很强的$b \rightarrow s γ$和$b \rightarrow s l^+ l^-$过程的分支比之间的相关性,干涉效应可以改变$b \rightarrow s l^+ l^-$的分支比在非共振区由高达$\pm 15%$取决于长距离和短距离的贡献之间的相对相位。使用各种唯象约束,包括$b \rightarrow s γ$的分支比,我们表明,有区域的参数空间中的分支比的$b \rightarrow s l^+ l^-$增强了约50%相比,SM。我们还表明,$b \rightarrow s ν{\overline ν}$的分支比从SM预测最多减少10%。
Study of localized $CP$ violation in $B^-\rightarrow π^- π^+π^-$ and the branching ratio of $B^-\rightarrow σ(600)π^-$ in the QCD factorization approach
$Z$ boson decays $Z\rightarrow{{l_i}^{\pm}{l_j}^{\mp}}$ and Higgs boson decays $h\rightarrow{{l_i}^{\pm}{l_j}^{\mp}}$ with lepton flavor violation in a $U(1)$ extension of the MSSM
Searching for lepton flavor violating decays tau to Pl in Minimal R-symmetric Supersymmetric Standard Model
在最小R对称超对称标准模型的情形下,分析了轻子味破坏衰变$τ\rightarrow Pl$($P=π,η,η';\;l=e,μ$)。对分支比BR $(τ\rightarrow P e)$和BR $(τ\rightarrow P μ)$的预测分别受到质量插入参数$δ^{13}$和$δ^{23}$的影响。这些参数受到分支比BR($τ\rightarrow e (μ) γ$)和BR($τ\rightarrow 3e(μ)$)的实验界限的约束。结果表明,$Z$企鹅在参数空间的大范围内主导BR($τ\rightarrow Pl$)的预测。BR($τ\rightarrow Pl$)的分支比预测为,至少,五个数量级小于目前的实验界限和三个数量级小于未来的实验灵敏度。
Rare top quark decays at a 100 TeV proton-proton collider: $t \rightarrow bWZ$ and $t\rightarrow hc$
我们研究了极罕见的顶夸克衰变在未来的质子-质子对撞机的质心能量为100 TeV。我们专注于两种衰变模式:辐射衰变与$Z$玻色子,$t \rightarrow b WZ$,和味道变化的中性衰变与希格斯玻色子,$t \rightarrow h c$,前者被运动学抑制与$\mathcal{O}(10^{-6})$的分支比,和后者高度环抑制,与分支比$\mathcal{O}(10^{-15})$。我们发现,$t \rightarrow b WZ$将是非常具有挑战性的观察顶夸克对的生产,即使在动机良好的超越标准模型的情况下。对于模式$t\rightarrow h c$,我们发现一个更强的灵敏度比任何未来的大型强子对撞机测量获得至少一个数量级。
Investigating $B_s$ three-body decays to scalar mesons in perturbative QCD approach
In this work, we study the branching ratios of B^{0}_{s} \rightarrow a_{0} (980)[ \rightarrow K \overline{K} , πη] a_{0} (980), B^{0}_{s} \rightarrow f_{0} (980)[ \rightarrow π^{+}π^{-}, K^{+}K^{-}] f_{0} (980) and B^{0}_{s} \rightarrow f_{0} (500)[ \rightarrow π^{+}π^{-}] f_{0} (500) decays in the pQCD approach, in which the scalar mesons a_{0} (980), f_{0} (980) and f_{0} (500) are regarded as the lowest-lying q \overline{q} state. In the SU(3) nonet, there exists a mixing between the scalars f_{0} (980) and f_{0} (500), so we have considered the mixing effect in our calculations to obtain m…
Investigation of the $B_c\rightarrow χ_{c2} l \barν $ transition via QCD sum rules
在QCD求和规则的框架下,考虑双胶子凝聚修正,计算了半轻子$B_c\rightarrow χ_{c2} l \barν $的跃迁形状因子。利用所得到的形状因子的结果,我们估计了在所有轻子通道中与这种跃迁有关的衰变宽度和分支比。所得结果与其他非微扰方法的预测进行了比较。不同轻子通道的分支比的顺序表明,$B_c\rightarrow χ_{c2} l \barν $跃迁可以在大型强子对撞机上利用收集到的或将来的数据进行研究。
Study of $Λ_b\rightarrow~ Λl^+l^-$ and $Λ_b\rightarrow p l \barν$ decays in the Bethe-Salpeter equation approach
在我们以前的工作中,基于$SU(6)$自旋味波函数,我们把$Λ$和$p$看作是由不同的夸克-双夸克组态组成,建立了夸克和标量双夸克组态的Bethe-Salpeter(BS)方程。在我们目前的工作中,我们应用该模型来计算标准模型(SM)中半轻子跃迁$Λ_b\rightarrowΛl^+l^-$ $(l=μ,e,τ)$和$Λ_b\rightarrow p l\barν$的形状因子。衰变$Λ_b\rightarrowΛμ^+μ^-$是特别有趣的,因为它已经在CDF和LHCb合作中测量,这种罕见的衰变对新的物理效应非常敏感。$Λ_b\rightarrow p l\barν$衰变是在大型强子对撞机上测量Cabibbo-Kobayashi-Maskawa矩阵元$|V_{ub}|$的一种很有前途的模式。在我们的计算中,根据BS方程核中双夸克质量和夸克与双夸克相互作用强度等模型参数的取值范围,我们发现,在我们的模型中,$Λ_b\rightarrowΛμ^+μ^-$的分支比与实验数据是一致的,目前LHCb的实验结果与我们计算的$Λ_b\rightarrowΛμ^+μ^-$的微分分支比一致,只是在较大的范围内动量传递区这表明仍有可能产生新的物理效应的空间。我们也给出了$Λ_b\rightarrowΛl^+l^-$和$Λ_b\rightarrow p l\barν$的总分支比与其它唯象方法的结果的比较。
Constraint on compactification scale via recently observed baryonic $Λ_b\rightarrow Λ\ell^+ \ell^-$ channel and analysis of the $Σ_b \rightarrow Σ\ell^+ \ell^-$ transition in SM and UED scenario
Study of the quasi-two-body decays B^{0}_{s} \rightarrow ψ(3770)(ψ(3686))π^+π^- with perturbative QCD approach
In this note, we study the contributions from the S-wave resonances, f_{0} (980) and f_{0} (1500), to the B^{0}_{s} \rightarrow ψ(3770)π^ {+}π^{-} decay by introducing the S-wave ππdistribution amplitudes within the framework of the perturbative QCD approach. Both resonant and nonresonant contributions are contained in the scalar form factor in the S-wave distribution amplitude Φ^ S_{ππ} . Since the vector charmonium meson ψ(3770) is a S-D wave mixed state, we calculated the branching ratios of S-wave and D-wave respectively, and the results indicate that f_{0} (980) is the main contribution o…
结合重夸克有效理论和手征拉格朗日方法,我们研究了D介子的辐射衰变。首先,我们重新分析$D^{*} \rightarrow D γ$衰变使用重夸克自旋对称性,手征对称性拉格朗日,但也包括轻矢量介子。然后,我们计算分支比$D \rightarrow V γ$。本文对Cabbibo抑制的$D \to ρ/ ωγ$衰变和$D \rightarrow P P γ$衰变的分支比作了一些评论。
In this work, we calculate the branching ratios and CP violations of the B^{0}_{s}\rightarrow a_{0}(980)a_{0}(980) decay modes with both charged and neutral a_{0}(980) mesons and B^{0}_{s}\rightarrow f_{0}(980)(f_{0}(500))f_{0}(980)(f_{0}(500)) for the first time in the pQCD approach. Considering the recent observation of the BESIII collaboration that provide a direct information about the constituent two-quark components in the corresponding a_{0}(980) wave functions, we regard the scalar mesons a_{0}(980), f_{0}(980) and f_{0}(500) as the q\bar{q} quark component in our present work, and the…
New results on the search for $B^0_s\rightarrow μ^+μ^-$ from LHCb
利用LHCb实验,使用在$\sqrt s=8$收集的1.1\,fb $^{-1}$数据,对稀有衰变$B^0_s\rightarrow μ^+μ^-$和$B^0\rightarrow μ^+μ^-$进行搜索,TeV $ and 1.0\,fb$ ^{-1} $ of data collected at $ \sqrt s=7 $\,TeV. An excess of $ B^0_s \rightarrow μ^+μ^- $ candidates with respect to the background expectations is observed with a statistical significance of 3.5 standard deviations. A branching fraction of $ { \cal BR}(B^0_s \rightarrow μ^+μ^-)=(3.2^{+1.5}_{-1.2})\times 10^{-9} $ is measured with an unbinned maximum likelihood fit. The measured branching fraction is in agreement with the expectation from the Standard Model. The observed n…