7 pages, 2 figures, 2 tables; parallel talk given at at "Particle Physics, Astrophysics and Quantum Field Theory: 75 Years since Solvay", November 27-29, 2008, Singapore
我们研究了末态为$D^{(*)}$或$J/Ψ$的迷人的三体重子B衰变。我们解释了$\bar B^0\to n\bar p D^{*+}$、$\bar B^0\to p\bar p D^{(*)0}$和$B^-\to Λ\bar p J/Ψ$的测量率。特别地，预测为$2.3\times 10^{-6}$级的$\bar B^0\toΛ\bar ΛD^0$的分支分数与Belle测量$(1.05^{+0.57}_{-0.44}\pm 0.14)\times 10^{-5}<2.6\times 10^{-5}$一致。
英文摘要：
We study the charmful three-body baryonic B decays with $D^{(*)}$ or $J/Ψ$ in the final state. We explain the measured rates of $\bar B^0\to n\bar p D^{*+}$, $\bar B^0\to p\bar p D^{(*)0}$, and $B^-\to Λ\bar p J/Ψ$. In particular, the branching fraction of $\bar B^0\toΛ\bar ΛD^0$ predicted to be of order $2.3\times 10^{-6}$ is in accordance with the Belle measurement, $(1.05^{+0.57}_{-0.44}\pm 0.14)\times 10^{-5}<2.6\times 10^{-5}$.
We examine the validity of the generalized factorization method and calculate the angular correlations in the charmful three-body baryonic decays of $\bar B^0\to Λ\bar p D^{(*)+}$. With the timelike baryonic form factors newly extracted from the measured baryonic $B$ decays, we obtain ${\cal B}(\bar B^0\to Λ\bar p D^+,Λ\bar p D^{*+})=(1.85\pm 0.30,2.75\pm 0.24)\times 10^{-5}$ to agree with the recent data from the BELLE Collaboration, which demonstrates that the theoretical approach based on the factorization still works well. For the angular distribution asymmetries, we find ${\cal A}_θ(\bar …
我们研究了末态为$D^{(*)}$或$J/Ψ$的有趣的三体重子B衰变。我们解释了$\bar B^0\to n\bar p D^{*+}$、$\bar B^0\to p\bar p D^{(*)0}$和$B^-\to Λ\bar p J/Ψ$的测量速率，并预测了$\bar B^0\to Λ\bar p D^{*+}$、$\bar B^0\to Σ^0\bar p D^{*+}$、$B^-\toΛ\bar p D^{0}$和$B^-\toΛ\bar p D^{*0}$的分支分数分别为$(1.2, 1.1, 1.1, 3.9)\times 10^{-5}$阶。$B$工厂可随时使用这些设备。
The role of $W$-exchange diagrams in baryonic $B$ decays is poorly understood, and often taken as insignificant and neglected. We show that charmful two-body baryonic $B\to {\bf B}_c \bar {\bf B}'$ decays provide a good test-bed for the study of the $W$-exchange topology, whose contribution is found to be non-negligible; here ${\bf B}_c$ is an anti-triplet or a sextet charmed baryon, and ${\bf \bar B}'$ an octet charmless (anti-)baryon. In particular, we calculate that ${\cal B}(\bar B^0\toΣ_c^{+}\bar p)=(2.9^{+0.8}_{-0.9})\times 10^{-6}$ in good agreement with the experimental upper bound. It…
Though not considered in general, purely baryonic decays could shed light on the puzzle of the baryon number asymmetry in the universe by means of a better understanding of the baryonic nature of our matter world. As such, they constitute a yet unexplored class of decay processes worth investigating. We propose to search for purely baryonic decay processes at the LHCb experiment. No such type of decay has ever been observed. In particular, we concentrate on the decay $Λ_b^0\to p\bar pn$, which is the simplest purely baryonic decay mode, with solely spin-1/2 baryons involved. We predict its dec…
The LHCb collaboration has presented first experimental evidence that spin-carrying matter and antimatter differ. The study looked at four-body decays of the $Λ_b^0$ baryon. Differences in the behaviour of matter and antimatter are associated with the non-invariance of fundamental interactions under the combined charge-conjugation and parity transformations, known as $C\!P$ violation. We discuss purely baryonic decay processes, i.e. decay processes involving only spin-carrying particles. They are yet unexplored elementary processes. Their study opens a new chapter of flavour physics in the rou…
We study the four-body baryonic $B\to {\bf B_1 \bar B_2}M_1 M_2$ decays with $\bf B_{1,2}$ ($M_{1,2}$) being charmless baryons (mesons). In accordance with the recent LHCb observations, each decay is considered to proceed through the $B\to M_1 M_2$ transition together with the production of a baryon pair. We obtain that ${\cal B}(B^-\to Λ\bar p π^+π^-)=(3.7^{+1.5}_{-1.0} )\times 10^{-6}$ and ${\cal B}(\bar B^0\to p\bar p π^+π^-,p\bar p π^+ K^-)=(3.0\pm 0.9,6.6\pm 2.4)\times 10^{-6}$, in agreement with the data. We also predict ${\cal B}(B^-\toΛ\bar p K^+ K^-)=(3.0^{+1.3}_{-0.9})\times 10^{-6}$…
We study for the first time the three-body charmless baryonic decays $\bar B^0_s\to \bar p ΛM^+ (p \bar ΛM^-)$, with $M=π, K$. We find that the branching ratios of $\bar B^0_s\to (\bar p ΛK^+$ and $p\bar ΛK^-)$ and $\bar B^0_s\to p\bar Λπ^-$ are $(5.1\pm 1.1)\times 10^{-6}$ and $(2.8\pm 1.5)\times 10^{-7}$, respectively, which agree with recent experimental results reported by the LHCb collaboration. In addition, we derive the relations \mbox{${\cal B}(\bar B^0_s\to \bar p ΛK^+)\simeq (f_K/f_π)^2(τ_{B^0_s}/τ_{B^0}) {\cal B}(\bar B^0\to \bar p Λπ^+)$} and ${\cal B}(\bar B^0_s\to p\bar Λπ^-)/{\c…
We study the three-body baryonic B decay $\bar{B}^{0}_{s}\rightarrow p\barΛ K^{-}$ within the framework of the pole model via the baryonic $Λ_{b}$ pole. In our calculation, we require the strong coupling constant $g_{Λ_{b}B_{s}Λ}$ and investigate if $g_{Λ_{b}B_{s}Λ}=10.49\pm1.57$ is adopted, the branching ratio agrees with the experimental result, reported by the LHCb collaboration.
We study the three-body baryonic decay $ \bar{B}^{0}\rightarrowΛ^+_c \bar{p} π^0$ based on the factorization approach. The most important Feynman diagrams for this decay mode are factorizable and non-factorizable contributions, so that the former plays the key role in the decay amplitude and the latter affects the amplitude coefficient $a_2$. We calculate the decay branching ratio for some values of $a_2$ in the range of $0.16-0.40$ and we find that the value of $a_2=0.17$ leads us to the result of $(1.50\pm0.21)\times10^{-4}$ which evidently agrees with the experimental result $(1.55\pm0.17\p…
我们指出了寻找无粲重子B衰变的新途径：与$η^\prime$有关的重子对产生很可能与两体$Kπ/ππ$模一样大，甚至稍大。我们将我们的论证以较弱的形式扩展到$B\to γ+ X_s$和$\ellν+X$。虽然计算是不可靠的，估计给出了$10^{-5}$ -$10^{-6}$阶的分支比，其中置信度是从最近的实验发现中获得的，即$B \to D^{*} p \bar n$、$D^{*} p \bar p π$并不远低于$D^*π$和$D^*ρ$的速率。对无粲重子模的观测将有助于阐明弱衰变到重子末态的动力学，而$Λ$ -重子的自我分析能力有助于CP-和T-破坏的研究。
本文讨论了在标准模型中三体重子B衰变的直接CP和T破坏。特别地，我们强调，$B^\pm\to p\bar p K^{*\pm}$中的直接CP违反不对称性约为22%，而$\bar B^0 \ra Λ\bar p π^+$中的直接$T$违反不对称性可高达12%，这对于KEK和SLAC以及SuperB和LHCb的当前B工厂是可访问的。
We study the baryonic fluctuations from second to eighth order involving electric charge, baryon number and strangeness below the quark-gluon plasma crossover and numerically known from lattice QCD calculations. By considering a particular realization of the Hadron Resonance Gas model, we provide evidence on the dominant role of quark-diquark degrees of freedom to describe excited baryonic resonances. After proving by means of suitable Polyakov loop correlators that the quark-diquark and the quark-antiquark forces coincide, $V_{\bar q q } (r) = V_{\bar q D } (r) + \textrm{const}$, we find that…
