cern.ch

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

[to restricted-access page]

Information

Tools

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
Bu2JpsiK2011_PT_Y.pdf
Bu2Jps[..].pdf [28 KiB]
HiDef png [567 KiB]
Thumbnail [452 KiB]
*.C file
Bu2JpsiK2012_PT_Y.pdf
Bd2Jps[..].pdf [24 KiB]
HiDef png [510 KiB]
Thumbnail [404 KiB]
*.C file
Bd2JpsiKst2011_PT_Y.pdf
Bd2Jps[..].pdf [28 KiB]
HiDef png [571 KiB]
Thumbnail [432 KiB]
*.C file
Bd2JpsiKst2012_PT_Y.pdf
Bs2Dsp[..].pdf [23 KiB]
HiDef png [512 KiB]
Thumbnail [392 KiB]
*.C file
Bs2Dspi2011_PT_Y.pdf
Bs2Dsp[..].pdf [26 KiB]
HiDef png [583 KiB]
Thumbnail [424 KiB]
*.C file
Bs2Dspi2012_PT_Y.pdf

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
Bd2JpsiKst2011_mass.pdf
Bd2Jps[..].pdf [32 KiB]
HiDef png [191 KiB]
Thumbnail [104 KiB]
*.C file
Bd2JpsiKst2011_time.pdf
Bs2Dsp[..].pdf [36 KiB]
HiDef png [221 KiB]
Thumbnail [121 KiB]
*.C file
Bs2Dspi2011_mass.pdf
Bs2Dsp[..].pdf [45 KiB]
HiDef png [187 KiB]
Thumbnail [97 KiB]
*.C file
Bs2Dspi2011_time.pdf
Bu2Jps[..].pdf [32 KiB]
HiDef png [192 KiB]
Thumbnail [105 KiB]
*.C file
Bu2JpsiK2011_mass.pdf

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
Bd2JpsiKst2012_mass.pdf
Bd2Jps[..].pdf [57 KiB]
HiDef png [198 KiB]
Thumbnail [107 KiB]
*.C file
Bd2JpsiKst2012_time.pdf
Bs2Dsp[..].pdf [37 KiB]
HiDef png [216 KiB]
Thumbnail [120 KiB]
*.C file
Bs2Dspi2012_mass.pdf
Bs2Dsp[..].pdf [47 KiB]
HiDef png [211 KiB]
Thumbnail [111 KiB]
*.C file
Bs2Dspi2012_time.pdf
Bu2Jps[..].pdf [32 KiB]
HiDef png [195 KiB]
Thumbnail [106 KiB]
*.C file
Bu2JpsiK2012_mass.pdf

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
Bd2JpsiKst2011_asym.pdf
Bd2Jps[..].pdf [64 KiB]
HiDef png [114 KiB]
Thumbnail [64 KiB]
*.C file
Bd2JpsiKst2012_asym.pdf
Bs2Dsp[..].pdf [19 KiB]
HiDef png [125 KiB]
Thumbnail [70 KiB]
*.C file
Bs2Dspi2011_asym.pdf
Bs2Dsp[..].pdf [20 KiB]
HiDef png [131 KiB]
Thumbnail [72 KiB]
*.C file
Bs2Dspi2012_asym.pdf

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_pt_2011.pdf
AP_eta[..].pdf [14 KiB]
HiDef png [143 KiB]
Thumbnail [141 KiB]
*.C file
AP_eta_2011.pdf
AP_pt_2012.pdf [14 KiB]
HiDef png [165 KiB]
Thumbnail [161 KiB]
*.C file
AP_pt_2012.pdf
AP_eta[..].pdf [14 KiB]
HiDef png [144 KiB]
Thumbnail [141 KiB]
*.C file
AP_eta_2012.pdf

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_pt_Bd2JpsiKst2011.pdf
AP_y_B[..].pdf [14 KiB]
HiDef png [132 KiB]
Thumbnail [132 KiB]
*.C file
AP_y_Bd2JpsiKst2011.pdf
AP_pt_[..].pdf [14 KiB]
HiDef png [152 KiB]
Thumbnail [152 KiB]
*.C file
AP_pt_Bd2JpsiKst2012.pdf
AP_y_B[..].pdf [14 KiB]
HiDef png [133 KiB]
Thumbnail [133 KiB]
*.C file
AP_y_Bd2JpsiKst2012.pdf

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_pt_Bs2Dspi2011.pdf
AP_y_B[..].pdf [14 KiB]
HiDef png [131 KiB]
Thumbnail [130 KiB]
*.C file
AP_y_Bs2Dspi2011.pdf
AP_pt_[..].pdf [14 KiB]
HiDef png [148 KiB]
Thumbnail [147 KiB]
*.C file
AP_pt_Bs2Dspi2012.pdf
AP_y_B[..].pdf [14 KiB]
HiDef png [130 KiB]
Thumbnail [131 KiB]
*.C file
AP_y_Bs2Dspi2012.pdf

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_pt_LB2011.pdf
AP_y_L[..].pdf [14 KiB]
HiDef png [131 KiB]
Thumbnail [130 KiB]
*.C file
AP_y_LB2011.pdf
AP_pt_[..].pdf [14 KiB]
HiDef png [150 KiB]
Thumbnail [148 KiB]
*.C file
AP_pt_LB2012.pdf
AP_y_L[..].pdf [14 KiB]
HiDef png [130 KiB]
Thumbnail [130 KiB]
*.C file
AP_y_LB2012.pdf

Animated gif made out of all figures.

PAPER-2016-062.gif
Thumbnail
thumbnail_PAPER-2016-062.gif

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
Table_1.pdf

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
Table_2.pdf

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
Table_3.pdf

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
Table_4.pdf

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
Table_5.pdf

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
Table_8.pdf

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
Table_9.pdf

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
Table_10.pdf

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
Table_11.pdf

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
Table_12.pdf

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
Table_13.pdf

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
Table_14.pdf

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
Table_15.pdf

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
Table_16.pdf

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
Table_17.pdf

Created on 26 April 2024.