论文标题
在$ b \ to x_c \ ell \barν_{\ ell} $ vat belle ii实验中的$ b \ to x_c \ el \ bar bar bar bar bar bar bar bar bar bar bar bar bar bar bar bar bar bar bar bar bar v \ bar bar的测量
Measurement of Lepton Mass Squared Moments in $B \to X_c \ell \bar ν_{\ell}$ Decays with the Belle II Experiment
论文作者
论文摘要
我们介绍了Lepton Mass的第一至第四瞬间的测量值$ q^2 $ \ mbox {$ b \ to x_c \，\ ell \，\ ell \，\barν_{\ ell} $} $} $}的衰减，用于$ \ ell = e，ull = e，μ$，并带有$ x_c $ a hadreonic a hadreonic a carronic a carronic carme charm Quark。这些结果在$υ（4s）$共振上使用$ 62.8 \，\ Mathrm {fb}^{ - 1} $对应于$ 62.8 \，\ Mathrm { - 1} $的$υ（4s）$共振样本，并由Belle II实验在2019年和2020年收集。 \ \ b \ kern 0.18em \ overline {\ kern -0.18em b} $衰减是使用多变量$ b $标记算法在HADRONIC DECAY模式下完全重建的。我们以$ q^2> 1.5 \;报告原始和中央时刻； \ Mathrm {gev^2/c^4} $升至$ q^2> 8.5 \; \ Mathrm {gev^2/c^4} $，最多可访问77 \％\％\％\ mbox {$ b \ to x_c \，\ ell \，\ ell \，\barν_{\ ell} $} $} $}相位空间。这是在实验挑战范围内的矩矩的第一个测量，即$ [1.5，2.5] \，\ mathrm {gev^2/c^4} $。
We present measurements of the first to fourth moments of the lepton mass squared $q^2$ of \mbox{$B \to X_c \, \ell\, \bar ν_{\ell}$} decays for $\ell = e, μ$ and with $X_c$ a hadronic system containing a charm quark. These results use a sample of electron-positron collisions at the $Υ(4S)$ resonance corresponding to $62.8 \, \mathrm{fb}^{-1}$ of integrated luminosity and collected by the Belle II experiment in 2019 and 2020. To identify the $X_c$ system and reconstruct $q^2$, one of the $B$ mesons from an $Υ(4S) \to B \kern 0.18em\overline{\kern -0.18em B}$ decay is fully reconstructed in a hadronic decay mode using a multivariate $B$ tagging algorithm. We report raw and central moments for $ q^2 > 1.5 \; \mathrm{GeV^2/c^4}$ up to $q^2 > 8.5 \; \mathrm{GeV^2/c^4}$, probing up to 77\% of the accessible \mbox{$B \to X_c \, \ell\, \bar ν_{\ell}$} phase space. This is the first measurement of moments in the experimentally challenging range of $[ 1.5, 2.5 ] \, \mathrm{GeV^2/c^4}$.
