CMS-HIN-14-004 ; CERN-PH-EP-2015-209 | ||
Study of B meson production in pPb collisions at ${\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} =$ 5.02 TeV using exclusive hadronic decays | ||
CMS Collaboration | ||
27 August 2015 | ||
Phys. Rev. Lett. 116 (2016) 032301 | ||
Abstract: The production cross sections of the $\mathrm{B}^+$, $\mathrm{B}^0$, and $\mathrm{B}^0_s$ mesons, and of their charge conjugates, are measured via exclusive hadronic decays in pPb collisions at the center-of-mass energy $ {\sqrt {\smash [b]{s_{_{\mathrm {NN}}}}}} = $ 5.02 TeV with the CMS detector at the CERN LHC. The dataset used for this analysis corresponds to an integrated luminosity of 34.6 nb$^{-1}$. The production cross sections are measured in the transverse momentum range between 10 and 60 GeV/$c$. No significant modification is observed compared to proton-proton perturbative QCD calculations scaled by the number of incoherent nucleon-nucleon collisions. These results provide a baseline for the study of in-medium b quark energy loss in PbPb collisions. | ||
Links: e-print arXiv:1508.06678 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; HepData record ; CADI line (restricted) ; |
Figures | |
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Figure 1:
Invariant mass distributions of $\rm {\mathrm {B}^{+}} +\rm {\mathrm {B}^{-}} $ (left), $\rm {\mathrm {B}^{0}} +\rm {\overline {\mathrm {B}^{0}}} $ (center), and $\rm {\mathrm {B}_{s}^{0}} +\rm {\overline {\mathrm {B}_{s}^{0}}} $ (right) candidates in the transverse momentum regions 10--15, 10--15, and 10--60 GeV/$c$, respectively. See text for details. |
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Figure 2:
The $ {p_{\mathrm {T}}} $-differential production cross section of $\rm {\mathrm {B}^{+}} $ (left), $\rm {\mathrm {B}^{0}} $ (center), and $\rm {\mathrm {B}_{s}^{0}} $ (right) measured in pPb collisions at $\sqrt {s_{_{\text {NN}}}} =$ 5.02 TeV. Vertical bars (boxes) correspond to statistical (systematic) uncertainties. The global systematic uncertainty, listed in each panel and not included in the data points, comprises the uncertainties in the integrated luminosity measurement and the Bmeson branching fractions. Results are compared to FONLL calculations [37-39], scaled by the number of binary NN collisions, represented by a continuous histogram. The dashed histograms represent the theoretical uncertainties for the FONLL reference. |
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Figure 3:
The nuclear modification factors $ {R_{\rm pA}} ^{\rm FONLL}( {p_{\mathrm {T}}} )$ of $\rm {\mathrm {B}^{+}} $ (left), $\rm {\mathrm {B}^{0}} $ (center), $\rm {\mathrm {B}_{s}^{0}} $ (right) measured in pPb collisions at $\sqrt {s_{_{\text {NN}}}} =$ 5.02 TeV. The statistical and systematic uncertainties on the pPb data are shown as bars and yellow boxes around the data points, respectively. The systematic uncertainties from the FONLL predictions are plotted separately as open blue boxes. The global systematic uncertainties are shown as full grey boxes at unity, and are not included in the data points. |
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Figure 4-a:
(left) The $ {y_{\rm CM}} $-differential production cross section of $\rm {\mathrm {B}^{+}} $ measured in pPb collisions at $\sqrt {s_{_{\text {NN}}}} =$ 5.02 TeV. Vertical bars (boxes) correspond to statistical (systematic) uncertainties. The listed global systematic uncertainty is not included in the data points. The result is compared to a FONLL calculation [37-39] represented by a continuous histogram. The dashed histograms represent the theoretical uncertainties for the FONLL reference. (right) The nuclear modification factor $ {R_{\rm pA}} ^{\rm FONLL}( {y_{\rm CM}} )$ of $\rm {\mathrm {B}^{+}} $ as a function of $ {y_{\rm CM}} $. The statistical and systematic uncertainties on the pPb data are shown as bars and yellow boxes around the data points, respectively. The systematic uncertainty from the FONLL reference is plotted separately as open blue boxes. The global systematic uncertainty is shown as a full grey box at unity, and is not included in the data points. |
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Figure 4-b:
(left) The $ {y_{\rm CM}} $-differential production cross section of $\rm {\mathrm {B}^{+}} $ measured in pPb collisions at $\sqrt {s_{_{\text {NN}}}} =$ 5.02 TeV. Vertical bars (boxes) correspond to statistical (systematic) uncertainties. The listed global systematic uncertainty is not included in the data points. The result is compared to a FONLL calculation [37-39] represented by a continuous histogram. The dashed histograms represent the theoretical uncertainties for the FONLL reference. (right) The nuclear modification factor $ {R_{\rm pA}} ^{\rm FONLL}( {y_{\rm CM}} )$ of $\rm {\mathrm {B}^{+}} $ as a function of $ {y_{\rm CM}} $. The statistical and systematic uncertainties on the pPb data are shown as bars and yellow boxes around the data points, respectively. The systematic uncertainty from the FONLL reference is plotted separately as open blue boxes. The global systematic uncertainty is shown as a full grey box at unity, and is not included in the data points. |
Summary |
In summary, the first measurements of the $\mathrm{B}^+$, $\mathrm{B}^0$, and $\mathrm{B}^0_s$ meson production cross sections in pPb collisions at $ \sqrt{s_{ \text{NN} } } = $ 5.02 TeV have been presented. The mesons are measured in $ | y_{ \rm{lab} } | <$ 2.4 and 10 $< p_{\mathrm{T}} <$ 60 GeV/$c$ via the reconstruction of one of their exclusive hadronic decay channels. Within the transverse momentum and rapidity ranges studied, no significant modifications are observed, considering the statistical and systematical uncertainties, when compared to pp FONLL calculations scaled by the number of incoherent nucleon-nucleon collisions. These results provide a baseline for the study of in-medium b quark energy loss in PbPb collisions. |
Compact Muon Solenoid LHC, CERN |