Measurement of $D_s^{\pm}$ production asymmetry in $pp$ collisions at $\sqrt{s} =7$ and 8 TeV

Information

LHCb-PAPER-2018-010
CERN-EP-2018-073
arXiv:1805.09869 [PDF]

(Submitted on 24 May 2018)
JHEP 08 (2018) 008
Inspire 1674916

Tools

Abstract

The inclusive $D_s^{\pm}$ production asymmetry is measured in $pp$ collisions collected by the LHCb experiment at centre-of-mass energies of $\sqrt{s} =7$ and 8 TeV. Promptly produced $D_s^{\pm}$ mesons are used, which decay as $D_s^{\pm}\to\phi\pi^{\pm}$, with $\phi\to K^+K^-$. The measurement is performed in bins of transverse momentum, $p_{\rm T}$, and rapidity, $y$, covering the range $2.5<p_{\rm T}<25.0$ GeV$/c$ and $2.0<y<4.5$. No kinematic dependence is observed. Evidence of nonzero $D_s^{\pm}$ production asymmetry is found with a significance of 3.3 standard deviations.

Figures and captions

Distribution of $ D ^+_ s $ candidates for the $\sqrt{s} =7$ and 8 TeV data sets as a function of $p_{\mathrm{ T}}$ and $ y$ . The binning scheme used for the $ A_{\rm P}( D ^+_ s )$ measurement is overlaid.	Fig1a.pdf [148 KiB] HiDef png [1 MiB] Thumbnail [543 KiB] *.C file
	Fig1b.pdf [170 KiB] HiDef png [1 MiB] Thumbnail [581 KiB] *.C file
Invariant mass distribution of the $ D ^+_ s $ candidates in the kinematic range (left) $2.0<y<3.0$ and $2.5< p_{\mathrm{ T}} <4.7 {\mathrm{ Ge V /}c} $, and (right) $3.5<y<4.5$ and $8.5< p_{\mathrm{ T}} <25.0 {\mathrm{ Ge V /}c} $ for the $\sqrt{s} =8$ TeV data set recorded with MagDown . Also shown is the result of the fit, indicating the signal and combinatorial background.	Fig2a.pdf [67 KiB] HiDef png [289 KiB] Thumbnail [209 KiB] *.C file
	Fig2b.pdf [65 KiB] HiDef png [312 KiB] Thumbnail [236 KiB] *.C file
Results of the LHCb measurement of the $ D ^+_ s $ production asymmetry as a function of $p_{\mathrm{ T}}$ for three different bins of rapidity, compared to the results from Pythia . Both are for the combined $\sqrt{s} =7$ and 8 TeV data sets. The uncertainties on the Pythia predictions are statistical only.	Fig3a.pdf [14 KiB] HiDef png [180 KiB] Thumbnail [157 KiB] *.C file
	Fig3b.pdf [14 KiB] HiDef png [182 KiB] Thumbnail [156 KiB] *.C file
	Fig3c.pdf [14 KiB] HiDef png [180 KiB] Thumbnail [155 KiB] *.C file
Results of the LHCb measurement of the $ D ^+_ s $ production asymmetry as a function of $p_{\mathrm{ T}}$ for three different bins of rapidity for the (left) $\sqrt{s} =7\mathrm{ Te V} $ and (right) $8\mathrm{ Te V} $ data sets, split between the magnet polarities Mag Up and MagDown .	Fig4a.pdf [14 KiB] HiDef png [143 KiB] Thumbnail [141 KiB] *.C file
	Fig4b.pdf [14 KiB] HiDef png [142 KiB] Thumbnail [142 KiB] *.C file
	Fig4c.pdf [14 KiB] HiDef png [143 KiB] Thumbnail [142 KiB] *.C file
	Fig4d.pdf [14 KiB] HiDef png [145 KiB] Thumbnail [143 KiB] *.C file
	Fig4e.pdf [14 KiB] HiDef png [141 KiB] Thumbnail [140 KiB] *.C file
	Fig4f.pdf [14 KiB] HiDef png [142 KiB] Thumbnail [142 KiB] *.C file
Results of the LHCb measurement of the $ D ^+_ s $ production asymmetry as a function of $p_{\mathrm{ T}}$ for three different bins of rapidity for the (left) $\sqrt{s} =7\mathrm{ Te V} $ and (right) $8\mathrm{ Te V} $ data sets, compared to the results from Pythia . The uncertainties of the Pythia prediction are statistical only.	Fig5a.pdf [14 KiB] HiDef png [178 KiB] Thumbnail [154 KiB] *.C file
	Fig5b.pdf [14 KiB] HiDef png [177 KiB] Thumbnail [155 KiB] *.C file
	Fig5c.pdf [14 KiB] HiDef png [182 KiB] Thumbnail [156 KiB] *.C file
	Fig5d.pdf [14 KiB] HiDef png [179 KiB] Thumbnail [154 KiB] *.C file
	Fig5e.pdf [14 KiB] HiDef png [177 KiB] Thumbnail [154 KiB] *.C file
	Fig5f.pdf [14 KiB] HiDef png [177 KiB] Thumbnail [153 KiB] *.C file
Animated gif made out of all figures.	PAPER-2018-010.gif Thumbnail

Tables and captions

Raw and detection asymmetries in percent, for the 7 and 8 TeV data sets. The detection asymmetries are determined on the data combined from all kinematic bins. The first uncertainty is statistical, the second systematic.	Table_1.pdf [61 KiB] HiDef png [88 KiB] Thumbnail [41 KiB] tex code
Values of the $ D ^+_ s $ production asymmetry in percent, including, respectively, the statistical and systematic uncertainties for each of the $ D ^+_ s $ kinematic bins using the combined $\sqrt{s} =7$ and $8\mathrm{ Te V} $ data sets. The statistical and systematic uncertainties include the corresponding contributions from the detection asymmetries, and are therefore correlated between the bins.	Table_2.pdf [48 KiB] HiDef png [48 KiB] Thumbnail [23 KiB] tex code
Values of the $ D ^+_ s $ production asymmetry in percent, including, respectively, the statistical and systematic uncertainty for each of the $ D ^+_ s $ kinematic bins using the $\sqrt{s} =7\mathrm{ Te V} $ data set.	Table_3.pdf [48 KiB] HiDef png [46 KiB] Thumbnail [22 KiB] tex code
Values of the $ D ^+_ s $ production asymmetry in percent, including, respectively, the statistical and systematic uncertainty for each of the $ D ^+_ s $ kinematic bins using the $\sqrt{s} =8\mathrm{ Te V} $ data set.	Table_4.pdf [48 KiB] HiDef png [47 KiB] Thumbnail [22 KiB] tex code

Supplementary Material [file]

Supplementary material full pdf	supple[..].pdf [248 KiB]
This ZIP file contains supplementary material for the publication LHCb-PAPER-2018-010. The files are: supplementary.pdf : An overview of the extra figures .pdf, .png, .eps, .C : The figures in various formats	Fig1a.pdf [16 KiB] HiDef png [180 KiB] Thumbnail [167 KiB] *C file
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	Fig3a.pdf [15 KiB] HiDef png [253 KiB] Thumbnail [215 KiB] *C file
	Fig3b.pdf [14 KiB] HiDef png [161 KiB] Thumbnail [140 KiB] *C file
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	Fig3d.pdf [14 KiB] HiDef png [162 KiB] Thumbnail [140 KiB] *C file
	Fig3e.pdf [15 KiB] HiDef png [233 KiB] Thumbnail [195 KiB] *C file
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