cern.ch

Measurement of the charm-mixing parameter $y_{CP}$

[to restricted-access page]

Information

Tools

Contact

Abstract

A measurement of the charm-mixing parameter $y_{CP}$ using $D^0 \to K^+ K^-$, $D^0 \to \pi^+ \pi^-$, and $D^0 \to K^- \pi^+$ decays is reported. The $D^0$ mesons are required to originate from semimuonic decays of $B^-$ and $\overline{B}^0$ mesons. These decays are partially reconstructed in a data set of proton-proton collisions at center-of-mass energies of 7 and 8 TeV collected with the LHCb experiment and corresponding to an integrated luminosity of 3 fb$^{-1}$. The $y_{CP}$ parameter is measured to be $(0.57 \pm 0.13(\rm{stat.}) \pm 0.09(\rm{syst.}))\%$, in agreement with, and as precise as, the current world-average value.

Figures and captions

Distribution of $ D ^0$ mass for candidates passing the selection with fit projections overlaid: (top) $ D ^0 \rightarrow K^+K^-$ decays, (center) $ D ^0 \rightarrow \pi^+\pi^-$ decays, and (bottom) $ D ^0 \rightarrow K^-\pi^+$ decays.

Fig1.pdf [27 KiB]
HiDef png [478 KiB]
Thumbnail [98 KiB]
*.C file
Fig1.pdf

Ratio of decay-time acceptances from simulation for (top) $ D ^0 \rightarrow K^+K^-$ over $ D ^0 \rightarrow K^-\pi^+$ decays and (bottom) $ D ^0 \rightarrow \pi^+\pi^-$ over $ D ^0 \rightarrow K^-\pi^+$ decays.

Fig2.pdf [18 KiB]
HiDef png [132 KiB]
Thumbnail [29 KiB]
*.C file
Fig2.pdf

Acceptance-corrected signal-yield ratio of (top) $ D ^0 \rightarrow K^+K^-$ over $ D ^0 \rightarrow K^-\pi^+$ decays and (bottom) $ D ^0 \rightarrow \pi^+\pi^-$ over $ D ^0 \rightarrow K^-\pi^+$ decays as a function of $ D ^0$ decay time, with fit projection overlaid.

Fig3.pdf [18 KiB]
HiDef png [271 KiB]
Thumbnail [65 KiB]
*.C file
Fig3.pdf

Animated gif made out of all figures.

PAPER-2018-038.gif
Thumbnail
thumbnail_PAPER-2018-038.gif

Tables and captions

Signal yields of the selected candidates.

Table_1.pdf [44 KiB]
HiDef png [70 KiB]
Thumbnail [13 KiB]
tex code
Table_1.pdf

Measured values of $\Delta_\Gamma$ and $ y_{ C\!P }$ . The first uncertainty is statistical, the second is systematic.

Table_2.pdf [51 KiB]
HiDef png [30 KiB]
Thumbnail [5 KiB]
tex code
Table_2.pdf

Supplementary Material [file]

This ZIP file contains supplemetary material for the publication LHCb-PAPER-2018-XXX. The files are: Supplementary-LHCb-PAPER-2018-XXX.pdf : An overview of the extra figures *.pdf, *.png, *.eps, *.C : The figures in various formats

Fig10.pdf [18 KiB]
HiDef png [294 KiB]
Thumbnail [68 KiB]
*C file
Fig10.pdf
Fig11.pdf [17 KiB]
HiDef png [270 KiB]
Thumbnail [56 KiB]
*C file
Fig11.pdf
Fig12.pdf [17 KiB]
HiDef png [279 KiB]
Thumbnail [59 KiB]
*C file
Fig12.pdf
Fig13.pdf [17 KiB]
HiDef png [288 KiB]
Thumbnail [58 KiB]
*C file
Fig13.pdf
Fig14.pdf [17 KiB]
HiDef png [290 KiB]
Thumbnail [60 KiB]
*C file
Fig14.pdf
Fig15.pdf [17 KiB]
HiDef png [266 KiB]
Thumbnail [55 KiB]
*C file
Fig15.pdf
Fig4.pdf [18 KiB]
HiDef png [308 KiB]
Thumbnail [69 KiB]
*C file
Fig4.pdf
Fig5.pdf [18 KiB]
HiDef png [300 KiB]
Thumbnail [70 KiB]
*C file
Fig5.pdf
Fig6.pdf [18 KiB]
HiDef png [278 KiB]
Thumbnail [64 KiB]
*C file
Fig6.pdf
Fig7.pdf [18 KiB]
HiDef png [280 KiB]
Thumbnail [65 KiB]
*C file
Fig7.pdf
Fig8.pdf [17 KiB]
HiDef png [245 KiB]
Thumbnail [57 KiB]
*C file
Fig8.pdf
Fig9.pdf [18 KiB]
HiDef png [294 KiB]
Thumbnail [66 KiB]
*C file
Fig9.pdf
LHCb-P[..].pdf [283 KiB]
HiDef png [544 KiB]
Thumbnail [95 KiB]
*C file
LHCb-PAPER-2018-038-supplementary.pdf

Created on 17 December 2018.Citation count from INSPIRE on 18 December 2018.