cern.ch

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

[to restricted-access page]

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 [263 KiB]
Thumbnail [219 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 [114 KiB]
Thumbnail [61 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 [140 KiB]
Thumbnail [138 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 [76 KiB]
Thumbnail [36 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 [31 KiB]
Thumbnail [16 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 [149 KiB]
Thumbnail [151 KiB]
*C file
Fig10.pdf
Fig11.pdf [17 KiB]
HiDef png [152 KiB]
Thumbnail [128 KiB]
*C file
Fig11.pdf
Fig12.pdf [17 KiB]
HiDef png [156 KiB]
Thumbnail [133 KiB]
*C file
Fig12.pdf
Fig13.pdf [17 KiB]
HiDef png [161 KiB]
Thumbnail [132 KiB]
*C file
Fig13.pdf
Fig14.pdf [17 KiB]
HiDef png [161 KiB]
Thumbnail [133 KiB]
*C file
Fig14.pdf
Fig15.pdf [17 KiB]
HiDef png [151 KiB]
Thumbnail [126 KiB]
*C file
Fig15.pdf
Fig4.pdf [18 KiB]
HiDef png [156 KiB]
Thumbnail [158 KiB]
*C file
Fig4.pdf
Fig5.pdf [18 KiB]
HiDef png [150 KiB]
Thumbnail [157 KiB]
*C file
Fig5.pdf
Fig6.pdf [18 KiB]
HiDef png [140 KiB]
Thumbnail [146 KiB]
*C file
Fig6.pdf
Fig7.pdf [18 KiB]
HiDef png [141 KiB]
Thumbnail [148 KiB]
*C file
Fig7.pdf
Fig8.pdf [17 KiB]
HiDef png [125 KiB]
Thumbnail [124 KiB]
*C file
Fig8.pdf
Fig9.pdf [18 KiB]
HiDef png [149 KiB]
Thumbnail [148 KiB]
*C file
Fig9.pdf
LHCb-P[..].pdf [283 KiB]
HiDef png [377 KiB]
Thumbnail [237 KiB]
*C file
LHCb-PAPER-2018-038-supplementary.pdf

Created on 11 July 2020.