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

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The production of B+- mesons in proton-proton collisions at sqrt(s)=7 TeV is studied using 35 pb-1 of data collected by the LHCb detector. The B+- mesons are reconstructed exclusively in the B+- -> J/psi K+- mode, with J/psi -> mu+ mu-. The differential production cross-section is measured as a function of the B+- transverse momentum in the fiducial region 0 < pT < 40 GeV/c and with rapidity 2.0 < y < 4.5. The total cross-section, summing up B+ and B-, is measured to be sigma(pp -> B+- X, 0 < pT < 40 GeV/c, 2.0 < y < 4.5) = 41.4 +- 1.5 (stat.) +- 3.1 (syst.) mub.

Figures and captions

Invariant mass distribution of the selected $ B ^\pm \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K^\pm$ \ candidates for one bin {\;\; } ($5.0< p_{\rm T}<5.5 {\mathrm{ Ge V /}c} $). The result of the fit to the model described in the text is superimposed.

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Differential production cross-section as a function of the $ B ^\pm$ transverse momentum. The left plot shows the full $p_{\rm T}$ range, the right plot shows a zoom of the $p_{\rm T}$ range of $0-12$ $ {\mathrm{ Ge V /}c}$ . The histogram (left) and the open circles with error bars (right) are the measurements. The red dashed lines in both plots are the upper and lower uncertainty limits of the FONLL computation. A hadronisation fraction $f_{\bar{b}\rightarrow B^+}$ of $(40.1\pm1.3)$% [10] is assumed to fix the overall scale. The uncertainty of the FONLL computation includes the uncertainties of the $b$-quark mass, renormalisation and factorisation scales, and CTEQ 6.6 PDF.

Fig2a.pdf [15 KiB]
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Fig2b.pdf [15 KiB]
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Animated gif made out of all figures.


Tables and captions

Differential $ B ^\pm$ \ production cross-section in bins of $ p_{\rm T}$ for $2.0<y<4.5$. The first and second quoted uncertainties are statistical and systematic, respectively.

Table_1.pdf [42 KiB]
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tex code

Created on 19 February 2021.