Measurement of the $B^{\pm}$ production cross-section in pp collisions at $\sqrt{s} =$ 7 and 13 TeV

Information

LHCb-PAPER-2017-037
CERN-EP-2017-254
arXiv:1710.04921 [PDF]

(Submitted on 13 Oct 2017)
JHEP 12 (2017) 026
Inspire 1630633

Tools

Abstract

The production of $B^{\pm}$ mesons is studied in $pp$ collisions at centre-of-mass energies of 7 and 13 TeV, using $B^{\pm}\rightarrow J/\psi K^{\pm}$ decays and data samples corresponding to 1.0 fb$^{-1}$ and 0.3 fb$^{-1}$, respectively. The production cross-sections summed over both charges and integrated over the transverse momentum range $0<p_{\text{T}}< 40$ GeV/$c$ and the rapidity range $2.0<y<4.5$ are measured to be $\sigma(pp \rightarrow B^{\pm} X, \sqrt{s} = \text{7 TeV}) = 43.0 \pm 0.2 \pm 2.5 \pm 1.7\mu b,$ $\sigma(pp \rightarrow B^{\pm} X, \sqrt{s} = \text{13 TeV}) = 86.6 \pm 0.5 \pm 5.4 \pm 3.4\mu b,$ where the first uncertainties are statistical, the second are systematic, and the third are due to the limited knowledge of the $B^{\pm}\rightarrow J/\psi K^{\pm}$ branching fraction. The ratio of the cross-section at 13 TeV to that at 7 TeV is determined to be $2.02\pm0.02\text{(stat)}\pm0.12\text{(syst)}$. Differential cross-sections are also reported as functions of $p_{\text{T}}$ and $y$. All results are in agreement with theoretical calculations based on the state-of-art fixed next-to-leading order quantum chromodynamics.

Figures and captions

Invariant mass distributions of $ B ^\pm$ candidates in the range ${3.5< p_{\mathrm{ T}} <4.0 {\mathrm{ Ge V /}c} }$ and ${2.5<y<3.0}$ using (left) $7\mathrm{ Te V} $ and (right) $13\mathrm{ Te V} $ data. The black points are the number of selected candidates in each bin, the blue curve represents the fit result, the red-dotted line represents the $ B ^\pm \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^\pm $ signal, and the green- and brown-dashed lines are contributions from the combinatorial and the Cabibbo-suppressed backgrounds. The Cabibbo-suppressed background contribution $ B ^\pm \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} \pi ^\pm $ is only just visible at masses above the signal peak.	Fig1a.pdf [83 KiB] HiDef png [289 KiB] Thumbnail [290 KiB] *.C file
	Fig1b.pdf [82 KiB] HiDef png [276 KiB] Thumbnail [280 KiB] *.C file
Measured $ B ^\pm$ double-differential production cross-sections at (top) $7\mathrm{ Te V} $ and (bottom) $13\mathrm{ Te V} $ as a function of $p_{\mathrm{ T}}$ and $y$. The black points represent the measured values, and the cyan bands are the FONLL predictions [28]. Each set of measurements and predictions in a given rapidity bin is offset by a multiplicative factor $10^{-m}$, where the offset factor is shown after the rapidity range. The error bars include both the statistical and systematic uncertainties.	Fig2a.pdf [66 KiB] HiDef png [211 KiB] Thumbnail [227 KiB] *.C file
	Fig2b.pdf [69 KiB] HiDef png [210 KiB] Thumbnail [228 KiB] *.C file
Measured $ B ^\pm$ differential cross-section at $7\mathrm{ Te V} $ as a function of (left) $p_{\mathrm{ T}}$ or (right) $y$. The black points represent the measured values, the blue-dashed line and cyan band represent the central values and uncertainties of the FONLL prediction [28]. The error bars include both the statistical and systematic uncertainties.	Fig3a.pdf [65 KiB] HiDef png [171 KiB] Thumbnail [170 KiB] *.C file
	Fig3b.pdf [61 KiB] HiDef png [189 KiB] Thumbnail [201 KiB] *.C file
Measured $ B ^\pm$ differential cross-section at $13\mathrm{ Te V} $ as a function of (left) $p_{\mathrm{ T}}$ or (right) $y$. The black points represent the measured values, the blue-dashed line and cyan band represent the central values and uncertainties of the FONLL prediction [28]. The error bars include both the statistical and systematic uncertainties.	Fig4a.pdf [65 KiB] HiDef png [176 KiB] Thumbnail [174 KiB] *.C file
	Fig4b.pdf [61 KiB] HiDef png [228 KiB] Thumbnail [243 KiB] *.C file
Ratio of the $ B ^\pm$ cross-section at $13\mathrm{ Te V} $ to that at $7\mathrm{ Te V} $ as a function of (left) $p_{\mathrm{ T}}$ or (right) $y$. The black points represent the measured values, the blue-dashed line and cyan band represent the central values and uncertainties of the FONLL prediction [28].	Fig5a.pdf [53 KiB] HiDef png [181 KiB] Thumbnail [181 KiB] *.C file
	Fig5b.pdf [41 KiB] HiDef png [145 KiB] Thumbnail [154 KiB] *.C file
Measured acceptance efficiency of $ B ^\pm$ events at (left) $7\mathrm{ Te V} $ and (right) $13\mathrm{ Te V} $ as a function of $p_{\mathrm{ T}}$ in different $y$ regions.	Fig6a.pdf [61 KiB] HiDef png [195 KiB] Thumbnail [173 KiB] *.C file
	Fig6b.pdf [61 KiB] HiDef png [192 KiB] Thumbnail [172 KiB] *.C file
Animated gif made out of all figures.	PAPER-2017-037.gif Thumbnail

Tables and captions

Summary of relative systematic uncertainties on the integrated production cross-sections at {$\sqrt{s}=$ 7} and $13\mathrm{ Te V} $, and the ratio of the cross-sections $R(13\mathrm{ Te V} /7\mathrm{ Te V} )$.	Table_1.pdf [41 KiB] HiDef png [92 KiB] Thumbnail [45 KiB] tex code
Measured $\varepsilon_{\text{tot}}$ of $ B ^\pm$ events at $7\mathrm{ Te V} $, in the bins of $ B ^\pm$ $p_{\mathrm{ T}}$ and $y$. The efficiencies and uncertainties are in percent.	Table_2.pdf [50 KiB] HiDef png [209 KiB] Thumbnail [100 KiB] tex code
Measured $\varepsilon_{\text{tot}}$ of $ B ^\pm$ events at $13\mathrm{ Te V} $, in the bins of $ B ^\pm$ $p_{\mathrm{ T}}$ and $y$. The efficiencies and uncertainties are in percent.	Table_3.pdf [50 KiB] HiDef png [201 KiB] Thumbnail [97 KiB] tex code
Measured $ B ^\pm$ double-differential cross-section (in units of $\mathrm{ nb}$ ) at $7\mathrm{ Te V} $, as a function of $p_{\mathrm{ T}}$ and $y$, in the rapidity regions of $2.0<y<2.5$, $2.5<y<3.0$, and $3.0<y<3.5$.	Table_4.pdf [50 KiB] HiDef png [311 KiB] Thumbnail [153 KiB] tex code
Measured $ B ^\pm$ double-differential cross-section (in units of $\mathrm{ nb}$ ) at $7\mathrm{ Te V} $, as a function of $p_{\mathrm{ T}}$ and $y$, in the rapidity regions of $3.5<y<4.0$ and $4.0<y<4.5$.	Table_5.pdf [50 KiB] HiDef png [311 KiB] Thumbnail [167 KiB] tex code
Measured $ B ^\pm$ double-differential cross-section (in units of $\mathrm{ nb}$ ) at $13\mathrm{ Te V} $, as a function of $p_{\mathrm{ T}}$ and $y$, in the rapidity regions of $2.0<y<2.5$, $2.5<y<3.0$, and $3.0<y<3.5$.	Table_6.pdf [50 KiB] HiDef png [307 KiB] Thumbnail [154 KiB] tex code
Measured $ B ^\pm$ double-differential cross-section (in units of $\mathrm{ nb}$ ) at $13\mathrm{ Te V} $, as a function of $p_{\mathrm{ T}}$ and $y$, in the rapidity regions of $3.5<y<4.0$ and $4.0<y<4.5$.	Table_7.pdf [50 KiB] HiDef png [336 KiB] Thumbnail [166 KiB] tex code
Measured $ B ^\pm$ differential cross-sections (in units of $\mathrm{ nb} $) at $7\mathrm{ Te V} $ and $13\mathrm{ Te V} $ as functions of $p_{\mathrm{ T}}$ in the range $2.0<y<4.5$. The cross-section ratio between $13\mathrm{ Te V} $ and $7\mathrm{ Te V} $ is also presented.	Table_8.pdf [50 KiB] HiDef png [322 KiB] Thumbnail [157 KiB] tex code
Measured $ B ^\pm$ differential cross-sections (in units of $ {\mathrm{ \upmu b}} $) at $7\mathrm{ Te V} $ and $13\mathrm{ Te V} $ as functions of $y$ in the $p_{\mathrm{ T}}$ range $0< p_{\mathrm{ T}} <40 {\mathrm{ Ge V /}c} $. The cross-section ratio between $13\mathrm{ Te V} $ and $7\mathrm{ Te V} $ is also presented.	Table_9.pdf [42 KiB] HiDef png [21 KiB] Thumbnail [32 KiB] tex code