cern.ch

Study of $D_{sJ}$ decays to $D^+K^0_{\rm S}$ and $D^0K^+$ final states in $pp$ collisions

[to restricted-access page]

Abstract

A study of $D^+\KS$ and $D^0K^+$ final states is performed in a sample of 1.0/fb of $pp$ collision data collected at a centre-of-mass energy of $\sqrt{s}=7$ TeV with the \lhcb detector. We confirm the existence of the $D_{s1}^*(2700)^+$ and $D_{sJ}^*(2860)^+$ excited states and measure their masses and widths to be {eqnarray} m(D_{s1}^*(2700)^+) &=& 2709.2 \pm 1.9({stat})\pm 4.5({syst}) {MeV}/c^2,\cr \Gamma(D_{s1}^*(2700)^+) &=& 115.8 \pm 7.3({stat}) \pm12.1({syst}) {MeV}/c^2,\cr m(D_{sJ}^*(2860)^+) &=& 2866.1 \pm 1.0({stat}) \pm 6.3({syst}) {MeV}/c^2,\cr \Gamma(D_{sJ}^*(2860)^+) &=& 69.9 \pm 3.2({stat}) \pm 6.6({syst}) {MeV}/c^2.\cr {eqnarray}

Figures and captions

Invariant mass distribution (points) for (a) $D^+$, (b) $D^0$, $ K ^0_{\rm\scriptscriptstyle S} $ decaying (c) inside and (d) outside the vertex detector. We show the total probability density function (solid curve), the signal component as a sum of Gaussian distributions (dotted curve) and a decreasing exponential distribution to describe the background component (dashed curve). The region within the vertical lines corresponds to $\pm3$ standard deviations in mass resolution from the measured peak.

Fig1a.pdf [19 KiB]
HiDef png [159 KiB]
Thumbnail [29 KiB]
*.C file
Fig1a.pdf
Fig1b.pdf [19 KiB]
HiDef png [142 KiB]
Thumbnail [26 KiB] *.C file
Fig1b.pdf
Fig1c.pdf [19 KiB]
HiDef png [139 KiB]
Thumbnail [26 KiB] *.C file
Fig1c.pdf
Fig1d.pdf [19 KiB]
HiDef png [153 KiB]
Thumbnail [26 KiB] *.C file
Fig1d.pdf

Invariant mass distributions for (a) $D^+ K ^0_{\rm\scriptscriptstyle S} $ and (b) $D^0K^+$.

Fig2a.pdf [18 KiB]
HiDef png [101 KiB]
Thumbnail [20 KiB]
*.C file
Fig2a.pdf
Fig2b.pdf [18 KiB]
HiDef png [106 KiB]
Thumbnail [21 KiB] *.C file
Fig2b.pdf

Invariant mass distributions (points) for (a) $D^+ K ^0_{\rm\scriptscriptstyle S} $ and (b) $D^0K^+$. We show the total simultaneous probability density function (solid line), the $D_{s2}^*(2573)^+$ (fine dotted line), $D_{s1}^*(2700)^+$ (dot-dot-dot dashed line), $D_{sJ}^*(2860)^+$ (dot dashed line) and background contribution (dashed line). Invariant mass distributions after combinatorial background subtraction are shown for (c) $D^+ K ^0_{\rm\scriptscriptstyle S} $ and (d) $D^0K^+$, where the vertical scales are truncated to show the $D_{s1}^*(2700)^+$ and $D_{sJ}^*(2860)^+$ signals more clearly.

Fig3a.pdf [39 KiB]
HiDef png [146 KiB]
Thumbnail [26 KiB]
*.C file
Fig3a.pdf
Fig3b.pdf [39 KiB]
HiDef png [135 KiB]
Thumbnail [25 KiB] *.C file
Fig3b.pdf
Fig3c.pdf [37 KiB]
HiDef png [199 KiB]
Thumbnail [38 KiB] *.C file
Fig3c.pdf
Fig3d.pdf [37 KiB]
HiDef png [197 KiB]
Thumbnail [35 KiB] *.C file
Fig3d.pdf

Animated gif made out of all figures.

PAPER-2012-016.gif
Thumbnail
thumbnail_PAPER-2012-016.gif

Tables and captions

Parameters for $D_{s1}^*(2700)^+$ and $D_{sJ}^*(2860)^+$ states, evaluated with binned fits to the samples. Masses and widths are given in units of $ {\mathrm{\,MeV\!/}c^2}$ . Uncertainties are statistical only.

Table_1.pdf [60 KiB]
HiDef png [40 KiB]
Thumbnail [7 KiB]
tex code
Table_1.pdf

Total number of events for $D_{s1}^*(2700)^+$ and $D_{sJ}^*(2860)^+$, evaluated with the reference fit. Uncertainties are statistical only.

Table_2.pdf [57 KiB]
HiDef png [46 KiB]
Thumbnail [9 KiB]
tex code
Table_2.pdf

Systematic uncertainties for the $D_{s1}^*(2700)^+$ and $D_{sJ}^*(2860)^+$ parameters. Mass and width uncertainties, $\delta m$ and $\delta\Gamma$, are given in units of $ {\mathrm{\,MeV\!/}c^2}$ . The total uncertainties are calculated as the quadratic sums of all contributions.

Table_3.pdf [47 KiB]
HiDef png [102 KiB]
Thumbnail [18 KiB]
tex code
Table_3.pdf

Created on 11 December 2018.Citation count from INSPIRE on 18 December 2018.