Measurement of $J/\psi$ polarization in $pp$ collisions at $\sqrt{s}=7$ TeV

The LHCb collaboration Aaij, R ; Abellan Beteta, C ; Adeva, B ; et al.
Eur.Phys.J.C 73 (2013) 2631, 2013.
Inspire Record 1244315 DOI 10.17182/hepdata.66242

An angular analysis of the decay $J/\psi \rightarrow \mu^{+} \mu^{-}$ is performed to measure the polarization of prompt $J/\psi$ mesons produced in $pp$ collisions at $\sqrt{s}=7\; \mathrm{TeV}$. The dataset corresponds to an integrated luminosity of 0.37 fb$^{-1}$ collected with the LHCb detector. The measurement is presented as a function of transverse momentum, $p_\mathrm{T}$, and rapidity, $y$, of the $J/\psi$ meson, in the kinematic region $2 < p_\mathrm{T} < 15\; \mathrm{GeV}/c$ and $2.0<y<4.5$.

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Version 2
Measurement of $V^0$ production ratios in $pp$ collisions at $\sqrt{s} = 0.9$ and 7\,TeV

The LHCb collaboration Aaij, R. ; Adeva, B. ; Adinolfi, M. ; et al.
JHEP 08 (2011) 034, 2011.
Inspire Record 917009 DOI 10.17182/hepdata.58685

The $\bar{\Lambda} / \Lambda$ and $\bar{\Lambda} / K^0_\mathrm{S}$ production ratios are measured by the LHCb detector from $0.3\,\mathrm{nb}^{-1}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 0.9$\,TeV and $1.8\,\mathrm{nb}^{-1}$ at $\sqrt{s} = 7$\,TeV. Both ratios are presented as a function of transverse momentum, $p_\mathrm{T}$, and rapidity, $y$, in the ranges {$0.15 < p_\mathrm{T} < 2.50\,\mathrm{GeV}/c$} and {$2.0<y<4.5$}. Results at the two energies are in good agreement as a function of rapidity loss, $\Delta y = y_\mathrm{beam} - y$, and are consistent with previous measurements. The ratio $\bar{\Lambda} / \Lambda$, measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio $\bar{\Lambda} / K^0_\mathrm{S}$, measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected.

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Measurement of $\psi(2S)$ meson production in $pp$ collisions at $\sqrt{s}$=7 TeV

The LHCb collaboration Aaij, R ; Abellan Beteta, C ; Adeva, B ; et al.
Eur.Phys.J.C 72 (2012) 2100, 2012.
Inspire Record 1104754 DOI 10.17182/hepdata.72881

The differential cross-section for the inclusive production of $\psi(2S)$ mesons in $pp$ collisions at $\sqrt{s}$ =7 TeV has been measured with the LHCb detector. The data sample corresponds to an integrated luminosity of 36 pb$^{-1}$ collected during 2010. The $\psi(2S)$ mesons are reconstructed in the decay channels $\psi(2S) \rightarrow \mu^{+} \mu^{-}$ and $\psi(2S)$ $\rightarrow$ $J$/$\psi \pi^{+}\pi^{-}$, with the $J$/$\psi$ meson decaying into two muons. Results are presented both for promptly produced $\psi(2S)$ mesons and for those originating from $b$-hadron decays. In the kinematic range $p_{\rm T}(\psi(2S))$ $\leq$ 16 GeV/$c$ and 2 < $y$($\psi(2S))$ $\leq$ 4.5 we measure \begin{eqnarray*} \sigma_{\rm prompt}(\psi(2S)) &=& 1.44 \pm 0.01~(\text{stat})\pm 0.12~(\text{syst})^{+0.20}_{-0.40}~(\text{pol})~{\rm \mu b}, \\ \sigma_{b}(\psi(2S)) &=& 0.25 \pm 0.01~(\text{stat}) \pm 0.02~(\text{syst})~{\rm \mu b}, \end{eqnarray*} where the last uncertainty on the prompt cross-section is due to the unknown $\psi(2S)$ polarization. Recent QCD calculations are found to be in good agreement with our measurements. Combining the present result with the LHCb $J$/$\psi$ measurements we determine the inclusive branching fraction \begin{equation*} \mathcal{B}(b \rightarrow \psi(2S) X) = (2.73 \pm 0.06~(\text{stat}) \pm 0.16~(\text{syst}) \pm 0.24~(\text{BF})) \times 10^{-3}, \end{equation*} where the last uncertainty is due to the $\mathcal{B}(b \rightarrow J/\psi X)$, $\mathcal{B}(J/\psi \rightarrow \mu^+ \mu^-)$ and $\mathcal{B}(\psi(2S) \rightarrow e^+ e^-)$ branching fraction uncertainties. All above results are corrected by an erratum included as an appendix.

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Measurement of $\psi(2S)$ polarisation in $pp$ collisions at $\sqrt{s}=7$ TeV

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
Eur.Phys.J.C 74 (2014) 2872, 2014.
Inspire Record 1283844 DOI 10.17182/hepdata.64674

The polarisation of prompt $\psi(2S)$ mesons is measured by performing an angular analysis of $\psi(2S)\rightarrow \mu^{+} \mu^{-}$ decays using proton-proton collision data, corresponding to an integrated luminosity of 1.0 fb$^{-1}$, collected by the LHCb detector at a centre-of-mass energy of 7 TeV. The polarisation is measured in bins of transverse momentum $p_\mathrm{T}$ and rapidity $y$ in the kinematic region $3.5<p_\mathrm{T}<15$ GeV$/c$ and $2.0<y<4.5$, and is compared to theoretical models. No significant polarisation is observed.

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Measurement of B meson production cross-sections in proton-proton collisions at sqrt(s)= 7 TeV

The LHCb collaboration Aaij, R ; Abellan Beteta, C ; Adeva, B ; et al.
JHEP 08 (2013) 117, 2013.
Inspire Record 1238809 DOI 10.17182/hepdata.74446

The production cross-sections of B mesons are measured in pp collisions at a centre-of-mass energy of 7 TeV, using data collected with the LHCb detector corresponding to a integrated luminosity of 0.36 fb-1. The B+, B0 and Bs0 mesons are reconstructed in the exclusive decays B+ -> J/psi K+, B0 -> J/psi K*0 and Bs0 -> J/psi phi, with J/psi -> mu+ mu-, K*0 -> K+ pi- and phi -> K+ K-. The differential cross-sections are measured as functions of B meson transverse momentum pT and rapidity y, in the range 0 < pT < 40 GeV/c and 2.0 < y < 4.5. The integrated cross-sections in the same pT and y ranges, including charge-conjugate states, are measured to be sigma(pp -> B+ + X) = 38.9 +- 0.3 (stat.) +- 2.5 (syst.) +- 1.3 (norm.) mub, sigma(pp -> B0 + X) = 38.1 +- 0.6 (stat.) +- 3.7 (syst.) +- 4.7 (norm.) mub, sigma(pp -> Bs0 + X) = 10.5 +- 0.2 (stat.) +- 0.8 (syst.) +- 1.0 (norm.) mub, where the third uncertainty arises from the pre-existing branching fraction measurements.

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Measurement of J/psi production in pp collisions at sqrt(s)=2.76 TeV

The LHCb collaboration Aaij, R ; Abellan Beteta, C ; Adametz, A ; et al.
JHEP 02 (2013) 041, 2013.
Inspire Record 1205646 DOI 10.17182/hepdata.72838

The production of J/psi mesons is studied with the LHCb detector using data from pp collisions at sqrt(s)=2.76 TeV corresponding to an integrated luminosity of 71 nb^-1. The differential cross-section for inclusive J/psi production is measured as a function of its transverse momentum pT. The cross-section in the fiducial region 0<pT<12 GeV/c and rapidity 2.0<y<4.5 is measured to be 5.6 +/- 0.1(stat) +/- 0.4 (syst) mub, with the assumption of unpolarised J/psi production. The fraction of J/psi production from b-hadron decays is measured to be (7.1 +/- 0.6 (stat) +/- 0.7 (syst)) %.

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Measurement of J/psi production in pp collisions at sqrt(s)=7 TeV

The LHCb collaboration Aaij, R. ; Adeva, B. ; Adinolfi, M. ; et al.
Eur.Phys.J.C 71 (2011) 1645, 2011.
Inspire Record 891233 DOI 10.17182/hepdata.57066

The production of $J/\psi$ mesons in proton-proton collisions at $\sqrt{s}$= 7 tev is studied with the LHCb detector at the LHC. The differential cross-section for prompt $J/\psi$ production is measured as a function of the $J/\psi$ transverse momentum p_{\rm T}\ and rapidity $y$ in the fiducial region $p_{\rm T}\in[0;14]$ GeV/c and $y\in[2.0;4.5]$. The differential cross-section and fraction of \j psi\ from $b$-hadron decays are also measured in the same p_{\rm T}\ and $y$ range s. The analysis is based on a data sample corresponding to an integrated luminos ity of 5.2 pb$^{-1}$. The measured cross-sections integrated over the fiducial region are $10.52\pm 0. 04\pm 1.40^{+1.64}_{-2.20}\mu b$ for $\mathrm{prompt}~J/\psi$ production and $1.14 \pm 0. 01\pm 0.16 \mu b$ for $J/\psi$ from $b$-hadron decays, where the first uncertainty is statistical and the second systematic. The $\mathrm{prompt}~J/\psi$ production cross-section is obtained assuming no $J/\psi$ polarisation and the third error indicates the acceptance uncertainty due to this assumption.

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Measurement of Upsilon production in pp collisions at sqrt{s}=2.76 TeV

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
Eur.Phys.J.C 74 (2014) 2835, 2014.
Inspire Record 1280929 DOI 10.17182/hepdata.63971

The production of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3 pb^{-1} collected in proton-proton collisions at a centre-of-mass energy of sqrt{s}=2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the Upsilon transverse momentum and rapidity, over the ranges p_T<15 GeV/c and 2.0<y<4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be sigma(pp -> Upsilon(1S) X) x B(Upsilon(1S) -> mu+mu-) = 1.111 +/- 0.043 +/- 0.044 nb, sigma(pp -> Upsilon(2S) X) x B(Upsilon(2S) -> mu+mu-) = 0.264 +/- 0.023 +/- 0.011 nb, sigma(pp -> Upsilon(3S) X) x B(Upsilon(3S) -> mu+mu-) = 0.159 +/- 0.020 +/- 0.007 nb, where the first uncertainty is statistical and the second systematic.

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Measurement of Upsilon production in pp collisions at {\surd}s = 7 TeV

The LHCb collaboration Aaij, R. ; Abellan Beteta, C. ; Adeva, B. ; et al.
Eur.Phys.J.C 72 (2012) 2025, 2012.
Inspire Record 1091071 DOI 10.17182/hepdata.58651

The production of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons in proton-proton collisions at the centre-of-mass energy of sqrt(s)=7 TeV is studied with the LHCb detector. The analysis is based on a data sample of 25 pb-1 collected at the Large Hadron Collider. The Upsilon mesons are reconstructed in the decay mode Upsilon -&gt; mu+ mu- and the signal yields are extracted from a fit to the mu+ mu- invariant mass distributions. The differential production cross-sections times dimuon branching fractions are measured as a function of the Upsilon transverse momentum pT and rapidity y, over the range pT &lt; 15 GeV/c and 2.0 &lt; y &lt; 4.5. The cross-sections times branching fractions, integrated over these kinematic ranges, are measured to be sigma(pp -&gt; Upsilon(1S) X) x B(Upsilon(1S)-&gt;mu+ mu-) = 2.29 {\pm} 0.01 {\pm} 0.10 -0.37 +0.19 nb, sigma(pp -&gt; Upsilon(2S) X) x B(Upsilon(2S)-&gt;mu+ mu-) = 0.562 {\pm} 0.007 {\pm} 0.023 -0.092 +0.048 nb, sigma(pp -&gt; Upsilon(3S) X) x B(Upsilon(3S)-&gt;mu+ mu-) = 0.283 {\pm} 0.005 {\pm} 0.012 -0.048 +0.025 nb, where the first uncertainty is statistical, the second systematic and the third is due to the unknown polarisation of the three Upsilon states.

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Measurement of charged particle multiplicities and densities in $pp$ collisions at $\sqrt{s}=7\;$TeV in the forward region

The LHCb collaboration Aaij, Roel ; Adeva, Bernardo ; Adinolfi, Marco ; et al.
Eur.Phys.J.C 74 (2014) 2888, 2014.
Inspire Record 1281685 DOI 10.17182/hepdata.63498

Charged particle multiplicities are studied in proton-proton collisions in the forward region at a centre-of-mass energy of $\sqrt{s} = 7\;$TeV with data collected by the LHCb detector. The forward spectrometer allows access to a kinematic range of $2.0<\eta<4.8$ in pseudorapidity, momenta down to $2\;$GeV/$c$ and transverse momenta down to $0.2\;$GeV/$c$. The measurements are performed using minimum-bias events with at least one charged particle in the kinematic acceptance. The results are presented as functions of pseudorapidity and transverse momentum and are compared to predictions from several Monte Carlo event generators.

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