论文标题
$ d^0- \ edline {d^0} $混合的分散性和吸收性CP违反
Dispersive and Absorptive CP Violation in $D^0- \overline{D^0}$ Mixing
论文作者
论文摘要
$ d^0- \ edline {d^0} $混合中的CP违规（CPV）用分散和吸收性`弱阶段'$ ϕ_f^m $和$ ϕ_F^γ$描述。它们对CPV进行参数化，该CPV源自$ d^0 $衰减的干扰，分别有和不带有带有吸收性混合的混合，对于CP共轭HADRONIC最终状态$ f $，$ \ bar f $。这些是不同的，并且是单独测量的效果。对于CP特征态最终状态，间接CPV仅取决于$ ϕ_f^m $（配件CPV），而$ ϕ_f^γ$（吸收性CPV）只能使用非CP EIGENSTATE最终状态进行探测。最终状态依赖阶段的测量$ ϕ_f^m $，$ ϕ_f^γ$确定固有的分散和吸收性混合阶段$ ϕ_2^m $和$ ϕ_2^γ$。后者是分散和吸收性混合振幅的参数$ m_ {12} $和$γ_{12} $，相对于它们的优势（$ΔU= 2 $）$ u $ -spin组件。由于近似普遍性，可以在实验上访问固有阶段：在SM中，并且在cabibbo中可忽略的新CPV阶段被抑制/双重抑制（CF/DCS）衰减，$ ϕ_f^{m，γ} $ neend $ new $ new $ nec/d dc/neend $ nec/new $ new \至k^\ pm x $，低于$ 10 \％$ cf/dcs衰变$ d^0 \ to k_ {s，l} x $（最高为确切已知的$ o（ε_k）$更正）。在单一抑制（SCS）衰减中，QCD污染以$ o（ε）$中的$ u $ -spin中断输入，可能很重要，但在$ o（ε^2）中的平均值超过$ f = k^+k^ - $ f = k^+k^ - $，$π^+π^+π^ - $。 SM估计产生$ ϕ_2^m，ϕ_2^γ= O（0.2 \％）$。适合当前数据的$ O（10）$较大的阶段以$2σ$，来自新物理学。基于天真的外推实验精度的拟合表明，在LHCB II期升级时，可以实现对$ ϕ_2^{m} $和$ ϕ_2^γ$的敏感性。
CP violation (CPV) in $D^0-\overline{D^0}$ mixing is described in terms of the dispersive and absorptive `weak phases' $ϕ_f^M$ and $ϕ_f^Γ$. They parametrize CPV originating from the interference of $D^0$ decays with and without dispersive mixing, and with and without absorptive mixing, respectively, for CP conjugate hadronic final states $f$, $\bar f$. These are distinct and separately measurable effects. For CP eigenstate final states, indirect CPV only depends on $ϕ_f^M$ (dispersive CPV), whereas $ϕ_f^Γ$ (absorptive CPV) can only be probed with non-CP eigenstate final states. Measurements of the final state dependent phases $ϕ_f^M$, $ϕ_f^Γ$ determine the intrinsic dispersive and absorptive mixing phases $ϕ_2^M$ and $ϕ_2^Γ$. The latter are the arguments of the dispersive and absorptive mixing amplitudes $M_{12}$ and $Γ_{12}$, relative to their dominant ($ΔU=2$) $U$-spin components. The intrinsic phases are experimentally accessible due to approximate universality: in the SM, and in extensions with negligible new CPV phases in Cabibbo favored/doubly Cabibbo suppressed (CF/DCS) decays, the deviation of $ϕ_f^{M,Γ}$ from $ϕ_2^{M,Γ}$ is negligible in CF/DCS decays $D^0 \to K^\pm X$, and below $10\% $ in CF/DCS decays $D^0 \to K_{S,L} X$ (up to precisely known $O(ε_K)$ corrections). In Singly Cabibbo Suppressed (SCS) decays, QCD pollution enters at $O(ε)$ in $U$-spin breaking and can be significant, but is $O(ε^2)$ in the average over $f=K^+K^-$, $π^+π^-$. SM estimates yield $ϕ_2^M, ϕ_2^Γ= O(0.2\%)$. A fit to current data allows $O(10)$ larger phases at $2σ$, from new physics. A fit based on naively extrapolated experimental precision suggests that sensitivity to $ϕ_2^{M}$ and $ϕ_2^Γ$ in the SM may be achieved at the LHCb Phase II upgrade.
