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

Information

LHCb-PAPER-2019-037
CERN-EP-2019-258
arXiv:1911.08594 [PDF]

(Submitted on 19 Nov 2019)
JHEP 02 (2020) 049
Inspire 1766239

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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.

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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
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