Precision measurement of the $\Xi_{cc}^{++}$ mass

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Abstract

A measurement of the $\Xi_{cc}^{++}$ mass is performed using data collected by the LHCb experiment between 2016 and 2018 in $pp$ collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.6 $\mathrm{fb}^{-1}$. The $\Xi_{cc}^{++}$ candidates are reconstructed via the decay modes $\Xi_{cc}^{++}\to\Lambda_c^+K^-\pi^+\pi^+$ and $\Xi_{cc}^{++}\to\Xi_c^+\pi^+$. The result, $3621.55 \pm 0.23{\rm (stat) } \pm 0.30 {\rm (syst) }{\rm MeV}/c^2$, is the most precise measurement of the $\Xi_{cc}^{++}$ mass to date.

Figures and captions

 Invariant-mass distributions of (left) $\Xi ^{++}_{ c c } \rightarrow \Lambda ^+_ c K ^- \pi ^+ \pi ^+$ and (right) $\Xi ^{++}_{ c c } \rightarrow \Xi ^+_ c \pi ^+$ decay candidates, in the mass range of 3470--3770 $\text{ Me V /}c^2$ and 3350--3800 $\text{ Me V /}c^2$ , respectively. The results of unbinned extended maximum-likelihood fits to the mass distributions are indicated by the blue solid lines. XiccPP[..].pdf [20 KiB] HiDef png [220 KiB] Thumbnail [187 KiB] *.C file XiccPP[..].pdf [20 KiB] HiDef png [269 KiB] Thumbnail [222 KiB] *.C file Measured $\Xi ^{++}_{ c c }$ mass values and uncertainties obtained with the decay modes $\Xi ^{++}_{ c c } \rightarrow \Lambda ^+_ c K ^- \pi ^+ \pi ^+$ and $\Xi ^{++}_{ c c } \rightarrow \Xi ^+_ c \pi ^+$ . The combination is performed using the best linear unbiased estimator [53,54]. The inner error bars represent statistical uncertainties and the outer error bars represent the quadratic sum of statistical and systematic uncertainties. The inner and outer green bands correspond to the uncertainties on the averaged value. XiccMa[..].pdf [13 KiB] HiDef png [82 KiB] Thumbnail [47 KiB] *.C file Animated gif made out of all figures. PAPER-2019-037.gif Thumbnail

Tables and captions

 Systematic uncertainties on the $\Xi ^{++}_{ c c }$ mass measurements using $\Xi ^{++}_{ c c } \rightarrow \Lambda ^+_ c K ^- \pi ^+ \pi ^+$ and $\Xi ^{++}_{ c c } \rightarrow \Xi ^+_ c \pi ^+$ decays. The total systematic uncertainty on each mode is calculated by summing the individual sources of uncertainty in quadrature, except for the uncertainty on the momentum-scale calibration of the $\Xi ^+_ c$ mass [50], that is added linearly to that of the $\Xi ^{++}_{ c c }$ mass. Table_1.pdf [70 KiB] HiDef png [60 KiB] Thumbnail [27 KiB] tex code

Supplementary Material [file]

 Supplementary material full pdf supple[..].pdf [197 KiB] This ZIP file contains supplemetary material for the publication LHCb-PAPER-2019-037. The files are: Supplementary.pdf : An overview of the extra figures *.pdf, *.png, *.eps, *.C : The figures in variuous formats Fig3a.pdf [20 KiB] HiDef png [336 KiB] Thumbnail [225 KiB] *C file Fig3b.pdf [19 KiB] HiDef png [250 KiB] Thumbnail [182 KiB] *C file Fig4a.pdf [16 KiB] HiDef png [90 KiB] Thumbnail [49 KiB] *C file Fig4b.pdf [16 KiB] HiDef png [85 KiB] Thumbnail [45 KiB] *C file Fig5.pdf [18 KiB] HiDef png [161 KiB] Thumbnail [158 KiB] *C file Fig6.pdf [25 KiB] HiDef png [182 KiB] Thumbnail [176 KiB] *C file

Created on 06 March 2021.