# Measurement of $B^0$, $B^0_s$, $B^+$ and $\Lambda^0_b$ production asymmetries in 7 and 8 TeV proton-proton collisions

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## Abstract

The $B^0$, $B^0_s$, $B^+$ and $\Lambda^0_b$ hadron production asymmetries are measured using a data sample corresponding to an integrated luminosity of 3.0 fb$^{-1}$, collected by the LHCb experiment in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. The measurements are performed as a function of transverse momentum and rapidity of the $b$ hadrons within the LHCb detector acceptance. The overall production asymmetries, integrated over transverse momentum and rapidity, are also determined.

## Figures and captions

 Distributions of $p_{\rm T}$ and $y$ for background-subtracted (top) $B ^+$ , (middle) $B ^0$ and (bottom) $B ^0_ s$ decays for data collected in proton-proton collisions at the centre-of-mass energies of (left) 7 and (right) 8 $\mathrm{ Te V}$ . The binning schemes are superimposed. Bu2Jps[..].pdf [25 KiB] HiDef png [517 KiB] Thumbnail [426 KiB] *.C file Bu2Jps[..].pdf [28 KiB] HiDef png [567 KiB] Thumbnail [452 KiB] *.C file Bd2Jps[..].pdf [24 KiB] HiDef png [510 KiB] Thumbnail [404 KiB] *.C file Bd2Jps[..].pdf [28 KiB] HiDef png [571 KiB] Thumbnail [432 KiB] *.C file Bs2Dsp[..].pdf [23 KiB] HiDef png [512 KiB] Thumbnail [392 KiB] *.C file Bs2Dsp[..].pdf [26 KiB] HiDef png [583 KiB] Thumbnail [424 KiB] *.C file Distributions of (left) invariant mass and (right) decay time for (top) $B ^0 \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^{*0}$, (middle) $B ^0_ s \rightarrow D ^-_ s \pi ^+$ and (bottom) of invariant mass for $B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+$ decays, with the results of the fit overlaid. The data were collected in proton-proton collisions at the centre-of-mass energy of 7 $\mathrm{ Te V}$ . The contributions of the various background sources are also shown. Below each plot are the normalized residual distributions. Bd2Jps[..].pdf [34 KiB] HiDef png [243 KiB] Thumbnail [134 KiB] *.C file Bd2Jps[..].pdf [32 KiB] HiDef png [191 KiB] Thumbnail [104 KiB] *.C file Bs2Dsp[..].pdf [36 KiB] HiDef png [221 KiB] Thumbnail [121 KiB] *.C file Bs2Dsp[..].pdf [45 KiB] HiDef png [187 KiB] Thumbnail [97 KiB] *.C file Bu2Jps[..].pdf [32 KiB] HiDef png [192 KiB] Thumbnail [105 KiB] *.C file Distributions of (left) invariant mass and (right) decay time for (top) $B ^0 \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^{*0}$, (middle) $B ^0_ s \rightarrow D ^-_ s \pi ^+$ and (bottom) of invariant mass for $B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+$ decays, with the results of the fit overlaid. The data were collected in proton-proton collisions at the centre-of-mass energy of 8 $\mathrm{ Te V}$ . The contributions of the various background sources are also shown. Below each plot are the normalized residual distributions. Bd2Jps[..].pdf [35 KiB] HiDef png [250 KiB] Thumbnail [138 KiB] *.C file Bd2Jps[..].pdf [57 KiB] HiDef png [198 KiB] Thumbnail [107 KiB] *.C file Bs2Dsp[..].pdf [37 KiB] HiDef png [216 KiB] Thumbnail [120 KiB] *.C file Bs2Dsp[..].pdf [47 KiB] HiDef png [211 KiB] Thumbnail [111 KiB] *.C file Bu2Jps[..].pdf [32 KiB] HiDef png [195 KiB] Thumbnail [106 KiB] *.C file Time-dependent raw asymmetries for candidates in the (top) $B ^0 \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^{*0}$ and (bottom) $B ^0_ s \rightarrow D ^-_ s \pi ^+$ signal mass regions with the results of the global fits overlaid. Left and right plots correspond to data recorded in proton-proton collisions at centre-of-mass energies of 7 and 8 $\mathrm{ Te V}$ , respectively. For the $B ^0_ s$ decay, the asymmetries are obtained by folding the decay-time distributions into one oscillation period, and the offset $t_{0}= 0.2$ ps corresponds to the selection requirement on the decay time. Bd2Jps[..].pdf [64 KiB] HiDef png [114 KiB] Thumbnail [65 KiB] *.C file Bd2Jps[..].pdf [64 KiB] HiDef png [114 KiB] Thumbnail [64 KiB] *.C file Bs2Dsp[..].pdf [19 KiB] HiDef png [125 KiB] Thumbnail [70 KiB] *.C file Bs2Dsp[..].pdf [20 KiB] HiDef png [131 KiB] Thumbnail [72 KiB] *.C file Dependence of $A_\mathrm{P}(B^+)$, for data collected in proton-proton collisions with centre-of-mass of energies of (top) 7 and (bottom) 8 $\mathrm{ Te V}$ , on (left) $p_{\rm T}$ and (right) $y$. The results of fits using a straight line with zero (solid line) or floating slope parameter (dashed line) are also shown. The fits take into account the correlations amongst the bins. AP_pt_2011.pdf [14 KiB] HiDef png [165 KiB] Thumbnail [161 KiB] *.C file AP_eta[..].pdf [14 KiB] HiDef png [143 KiB] Thumbnail [141 KiB] *.C file AP_pt_2012.pdf [14 KiB] HiDef png [165 KiB] Thumbnail [161 KiB] *.C file AP_eta[..].pdf [14 KiB] HiDef png [144 KiB] Thumbnail [141 KiB] *.C file Dependence of $A_\mathrm{P}(B^0)$, for data collected in proton-proton collisions with centre-of-mass of energies of (top) 7 and (bottom) 8 $\mathrm{ Te V}$ , on (left) $p_{\rm T}$ and (right) $y$. The results of fits using a straight line with zero (solid line) or floating slope parameter (dashed line) are also shown. The fits take into account the correlations amongst the bins. AP_pt_[..].pdf [14 KiB] HiDef png [153 KiB] Thumbnail [151 KiB] *.C file AP_y_B[..].pdf [14 KiB] HiDef png [132 KiB] Thumbnail [132 KiB] *.C file AP_pt_[..].pdf [14 KiB] HiDef png [152 KiB] Thumbnail [152 KiB] *.C file AP_y_B[..].pdf [14 KiB] HiDef png [133 KiB] Thumbnail [133 KiB] *.C file Dependence of $A_\mathrm{P}( B ^0_ s )$, for data collected in proton-proton collisions with centre-of-mass of energies of (top) 7 and (bottom) 8 $\mathrm{ Te V}$ , on (left) $p_{\rm T}$ and (right) $y$. The results of fits with a straight line with zero (solid line) or floating slope parameter (dashed line) are also shown. The fits take into account the correlations amongst the bins. AP_pt_[..].pdf [14 KiB] HiDef png [149 KiB] Thumbnail [148 KiB] *.C file AP_y_B[..].pdf [14 KiB] HiDef png [131 KiB] Thumbnail [130 KiB] *.C file AP_pt_[..].pdf [14 KiB] HiDef png [148 KiB] Thumbnail [147 KiB] *.C file AP_y_B[..].pdf [14 KiB] HiDef png [130 KiB] Thumbnail [131 KiB] *.C file Dependence of $A_\mathrm{P}(\Lambda ^0_ b )$, for data collected in proton-proton collisions with centre-of-mass of energies of (top) 7 and (bottom) 8 $\mathrm{ Te V}$ , on (left) $p_{\rm T}$ and (right) $y$. The results of fits with a straight line with zero (solid line) or floating slope parameter (dashed line) are also shown. The fits take into account the correlations amongst the bins. AP_pt_[..].pdf [14 KiB] HiDef png [148 KiB] Thumbnail [147 KiB] *.C file AP_y_L[..].pdf [14 KiB] HiDef png [131 KiB] Thumbnail [130 KiB] *.C file AP_pt_[..].pdf [14 KiB] HiDef png [150 KiB] Thumbnail [148 KiB] *.C file AP_y_L[..].pdf [14 KiB] HiDef png [130 KiB] Thumbnail [130 KiB] *.C file Animated gif made out of all figures. PAPER-2016-062.gif Thumbnail

## Tables and captions

 Values of the various physical inputs used in the fits, as reported in Ref. [33]. Table_1.pdf [65 KiB] HiDef png [160 KiB] Thumbnail [68 KiB] tex code Values of signal yields, $A_{\rm P}$ and $A_{\rm D}$ obtained from global fits for the two neutral $B$ -meson decays under study. Table_2.pdf [53 KiB] HiDef png [46 KiB] Thumbnail [18 KiB] tex code Values of signal yields and raw asymmetries obtained from global fits in the case of the $B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+$ decay. Table_3.pdf [37 KiB] HiDef png [42 KiB] Thumbnail [20 KiB] tex code Absolute values of systematic uncertainties for integrated production asymmetries. The total systematic uncertainties are obtained by summing the individual contributions in quadrature. Table_4.pdf [71 KiB] HiDef png [361 KiB] Thumbnail [154 KiB] tex code Values for $m$ and $q$ and their correlation coefficient ($\rho$) obtained from fits to the values reported in Tables 10--17 with a first order polynomial function (FOPF), $A_{\mathrm{P}}(b \mathrm{hadron}) = a x + b$ with $x = p_{\rm T} ,y$. The label SL indicates the fit to the values with a straight line. Table_5.pdf [56 KiB] HiDef png [182 KiB] Thumbnail [95 KiB] tex code Values of $A_{\rm P}( B ^0_ s )$ and $A_{\rm P}(\Lambda ^0_ b )$ in each kinematic bin for data collected in proton-proton collisions at centre-of-mass energy of 7 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. Table_8.pdf [51 KiB] HiDef png [166 KiB] Thumbnail [75 KiB] tex code Values of $A_{\rm P}( B ^0_ s )$ and $A_{\rm P}(\Lambda ^0_ b )$ in each kinematic bin for data collected in proton-proton collisions at centre-of-mass energy of 8 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. Table_9.pdf [51 KiB] HiDef png [165 KiB] Thumbnail [75 KiB] tex code Values of the production asymmetries in bins of $p_{\rm T}$, integrated over $y$, for $B ^+$ and $B ^0$ mesons for data collected in proton-proton collisions at the centre-of-mass energy of 7 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$ and $A_{\rm D}(\overline{ K }{} {}^0 )$ for $A_{\rm P}( B ^+ )$, and $|q/p|$ for $A_{\rm P}( B ^0 )$. Table_10.pdf [50 KiB] HiDef png [109 KiB] Thumbnail [61 KiB] tex code Values of the production asymmetries in bins of $y$, integrated over $p_{\rm T}$, for $B ^+$ and $B ^0$ mesons for data collected in proton-proton collisions at the centre-of-mass energy of 7 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$ and $A_{\rm D}(\overline{ K }{} {}^0 )$ for $A_{\rm P}( B ^+ )$, and $|q/p|$ for $A_{\rm P}( B ^0 )$. Table_11.pdf [48 KiB] HiDef png [105 KiB] Thumbnail [50 KiB] tex code Values of the production asymmetries in bins of $p_{\rm T}$, integrated over $y$, for $B ^+$ and $B ^0$ mesons for data collected in proton-proton collisions at the centre-of-mass energy of 8 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$ and $A_{\rm D}(\overline{ K }{} {}^0 )$ for $A_{\rm P}( B ^+ )$, and $|q/p|$ for $A_{\rm P}( B ^0 )$. Table_12.pdf [50 KiB] HiDef png [106 KiB] Thumbnail [61 KiB] tex code Values of the production asymmetries in bins of $y$, integrated over $p_{\rm T}$, for $B ^+$ and $B ^0$ mesons for data collected in proton-proton collisions at the centre-of-mass energy of 8 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$ and $A_{\rm D}(\overline{ K }{} {}^0 )$ for $A_{\rm P}( B ^+ )$, and $|q/p|$ for $A_{\rm P}( B ^0 )$. Table_13.pdf [48 KiB] HiDef png [104 KiB] Thumbnail [49 KiB] tex code Values of the production asymmetries in bins of $p_{\rm T}$, integrated over $y$, for the $B ^0_ s$ meson and the $\Lambda ^0_ b$ baryon for data collected in proton-proton collisions at the centre-of-mass energy of 7 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$, $A_{\rm D}(\overline{ K }{} {}^0 )$, $|q/p|_{ B ^0 }$ and $|q/p|_{ B ^0_ s }$ for $A_{\rm P}(\Lambda ^0_ b )$, and $|q/p|_{ B ^0_ s }$ for $A_{\rm P}( B ^0_ s )$. Table_14.pdf [50 KiB] HiDef png [66 KiB] Thumbnail [32 KiB] tex code Values of the production asymmetries in bins of $y$, integrated over $p_{\rm T}$, for the $B ^0_ s$ meson and the $\Lambda ^0_ b$ baryon for data collected in proton-proton collisions at the centre-of-mass energy of 7 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$, $A_{\rm D}(\overline{ K }{} {}^0 )$, $|q/p|_{ B ^0 }$ and $|q/p|_{ B ^0_ s }$ for $A_{\rm P}(\Lambda ^0_ b )$, and $|q/p|_{ B ^0_ s }$ for $A_{\rm P}( B ^0_ s )$. Table_15.pdf [48 KiB] HiDef png [51 KiB] Thumbnail [24 KiB] tex code Values of the production asymmetries in bins of $p_{\rm T}$, integrated over $y$, for the $B ^0_ s$ meson and the $\Lambda ^0_ b$ baryon for data collected in proton-proton collisions at the centre-of-mass energy of 8 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated, due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$, $A_{\rm D}(\overline{ K }{} {}^0 )$, $|q/p|_{ B ^0 }$ and $|q/p|_{ B ^0_ s }$, for $A_{\rm P}(\Lambda ^0_ b )$ and $|q/p|_{ B ^0_ s }$ for $A_{\rm P}( B ^0_ s )$. Table_16.pdf [50 KiB] HiDef png [66 KiB] Thumbnail [32 KiB] tex code Values of the production asymmetries in bins of $y$, integrated over $p_{\rm T}$, for the $B ^0_ s$ meson and the $\Lambda ^0_ b$ baryon for data collected in proton-proton collisions at the centre-of-mass energy of 8 $\mathrm{ Te V}$ . The first uncertainties are statistical and the second systematic. The uncertainties among the bins are correlated, due to the external inputs: $A_{ C P }( B ^+ \rightarrow { J \mskip -3mu/\mskip -2mu\psi \mskip 2mu} K ^+ )$, $A_{\rm D}(\overline{ K }{} {}^0 )$, $|q/p|_{ B ^0 }$ and $|q/p|_{ B ^0_ s }$, for $A_{\rm P}(\Lambda ^0_ b )$ and $|q/p|_{ B ^0_ s }$ for $A_{\rm P}( B ^0_ s )$. Table_17.pdf [48 KiB] HiDef png [52 KiB] Thumbnail [25 KiB] tex code

Created on 07 August 2020.