The production of $\Lambda^+_c$ baryons produced directly at the interacting point is studied in protonlead collisions collected with the LHCb detector at the LHC. The data sample corresponds to an integrated luminosity of $1.58\mathrm{nb}^{1}$ recorded at a nucleonnucleon centreofmass energy of $\sqrt{s_{NN}}=5.02$ TeV. Measurements of the differential crosssection and the forwardbackward production ratio are reported for $\Lambda^+_c$ baryons with transverse momenta in the range $2<p_{T}<10$GeV/$c$ and rapidities in the ranges $1.5<y^*<4.0$ and $4.5<y^*<2.5$ in the nucleonnucleon centreofmass system. The ratio of crosssections of $\Lambda^+_c$ baryons and $D^0$ mesons is also reported. The results are compared with nexttoleading order calculations that use nuclear parton distribution functions.
Distributions of the invariant mass, $m( p K ^ \pi ^+ )$, in the range $2< p_{\mathrm{ T}} <10 {\mathrm{\,GeV\!/}c} $ for (a) the forward data sample with $1.5<y^*<4.0$ and (b) the backward data sample with $4.5<y^*<2.5$. The red dotted line is the inclusive $\Lambda ^+_ c $ candidates, the grey shaded area is the combinatorial background and the blue solid line is the sum of the two. 
Fig1a.pdf [28 KiB] HiDef png [417 KiB] Thumbnail [96 KiB] 

Fig1b.pdf [28 KiB] HiDef png [681 KiB] Thumbnail [132 KiB] 

Distributions of $\log_{10}\chi^2_{\text{IP}} (\Lambda ^+_ c ) $ in the range $2< p_{\mathrm{ T}} <10 {\mathrm{\,GeV\!/}c} $ with the fit results overlaid for (a) the forward data sample with $1.5<y^*<4.0$, and (b) the backward data sample with $4.5<y^*<2.5$. The solid blue curve is the sum. The red dotted line is the prompt component, the green is the $\Lambda ^+_ c \mathrm{\text{}from\text{}} b $ component and the grey shaded area denotes the combinatorial background. 
Fig2a.pdf [23 KiB] HiDef png [356 KiB] Thumbnail [97 KiB] 

Fig2b.pdf [24 KiB] HiDef png [444 KiB] Thumbnail [111 KiB] 

Doubledifferential crosssection of prompt $\Lambda ^+_ c $ baryons in $ p\mathrm{Pb} $ collisions in the (a) forward and (b) backward collision samples. The uncertainty represents the quadratic sum of the statistical and the systematic uncertainties. 
Fig3a.pdf [17 KiB] HiDef png [212 KiB] Thumbnail [72 KiB] 

Fig3b.pdf [17 KiB] HiDef png [202 KiB] Thumbnail [70 KiB] 

Differential crosssection of prompt $\Lambda ^+_ c $ baryons in $ p\mathrm{Pb} $ collisions as a function of (a) $ p_{\mathrm{ T}} $ and (b) $y^{*}$ in the forward and backward samples. The forward and backward differential crosssections $\mathrm{d}\sigma/\mathrm{d} p_{\mathrm{ T}} $ in the common rapidity region $2.5<y^*<4.0$ are scaled by 0.1 to improve the visibility. The uncertainty represents the quadratic sum of the statistical and the systematic uncertainties. 
Fig4a.pdf [16 KiB] HiDef png [194 KiB] Thumbnail [74 KiB] 

Fig4b.pdf [14 KiB] HiDef png [126 KiB] Thumbnail [50 KiB] 

(a) Forwardbackward production ratios $R_\mathrm{FB}$ as a function of $ p_{\mathrm{ T}} $ integrated over $2.5<y^*<4.0$ for $ p_{\mathrm{ T}} $ less than $7 {\mathrm{\,GeV\!/}c} $ and $2.5<y^*<3.5$ for $ p_{\mathrm{ T}} $ greater than $7 {\mathrm{\,GeV\!/}c} $, and (b) $R_\mathrm{FB}$ as a function of $y^*$ integrated over $2< p_{\mathrm{ T}} <10 {\mathrm{\,GeV\!/}c} $. The uncertainty represents the quadratic sum of the statistical and the systematic uncertainties. 
Fig5a.pdf [17 KiB] HiDef png [650 KiB] Thumbnail [119 KiB] 

Fig5b.pdf [16 KiB] HiDef png [518 KiB] Thumbnail [96 KiB] 

The crosssection ratio $ R_{\Lambda ^+_ c / D ^0 }$ between $\Lambda ^+_ c $ baryons and $ D ^0$ mesons as a function of $ p_{\mathrm{ T}} $ integrated over four different rapidity regions. The uncertainty represents the sum in quadrature of the statistical and the systematic uncertainties. The coloured curves represent HELACOnia calculations with nPDF EPS09LO/NLO and nCTEQ15. 
Fig6a.pdf [17 KiB] HiDef png [164 KiB] Thumbnail [53 KiB] 

Fig6b.pdf [18 KiB] HiDef png [168 KiB] Thumbnail [54 KiB] 

Fig6c.pdf [17 KiB] HiDef png [170 KiB] Thumbnail [54 KiB] 

Fig6d.pdf [17 KiB] HiDef png [166 KiB] Thumbnail [53 KiB] 

The crosssection ratio $ R_{\Lambda ^+_ c / D ^0 }$ between $\Lambda ^+_ c $ baryons and $ D ^0$ mesons as a function of $y^*$ integrated over $2< p_{\mathrm{ T}} <10 {\mathrm{\,GeV\!/}c} $. The uncertainty represents the sum in quadrature of the statistical and the systematic uncertainties. The coloured curves show HELACOnia calculations incorporating nPDFs EPS09LO/NLO and nCTEQ15. 
Fig7.pdf [19 KiB] HiDef png [171 KiB] Thumbnail [48 KiB] 

Animated gif made out of all figures. 
PAPER2018021.gif Thumbnail 
Systematic and statistical uncertainties for the differential crosssections. The ranges indicate the variation over the ($ p_{\mathrm{ T}} , y^*$) bins. 
Table_1.pdf [56 KiB] HiDef png [102 KiB] Thumbnail [15 KiB] tex code 

Measured differential crosssection (in $\mathrm{ \,mb} /( {\mathrm{\,GeV\!/}c} )$) of prompt $\Lambda ^+_ c $ baryons as a function of $ p_{\mathrm{ T}} $ in $ p\mathrm{Pb} $ forward and backward data in different rapidity regions. The right column shows the results for $ p_{\mathrm{ T}} > 7 {\mathrm{\,GeV\!/}c} $ and $2.5<y^*<3.5$, which are used to compute the $ R_\mathrm{FB} $ values at $ p_{\mathrm{ T}} > 7 {\mathrm{\,GeV\!/}c} $. The first uncertainties are statistical and the second are systematic. 
Table_2.pdf [46 KiB] HiDef png [135 KiB] Thumbnail [19 KiB] tex code 

Differential crosssection (in $\mathrm{ \,mb} $) for prompt $\Lambda ^+_ c $ baryons as a function of $y^{*}$ in $ p\mathrm{Pb} $ forward and backward data. The first uncertainties are statistical and the second are systematic. 
Table_3.pdf [45 KiB] HiDef png [185 KiB] Thumbnail [27 KiB] tex code 

Forwardbackward prompt $\Lambda ^+_ c $ production ratio $ R_\mathrm{FB} $ as a function of $ p_{\mathrm{ T}} $ in the common range $2.5<y^*<4.0$. The first uncertainty is statistical and the second is systematic. 
Table_5.pdf [35 KiB] HiDef png [136 KiB] Thumbnail [19 KiB] tex code 

$ R_\mathrm{FB} $ ratio as a function of $y^*$ in the range $2< p_{\mathrm{ T}} <10 {\mathrm{\,GeV\!/}c} $. The first uncertainty is statistical and the second is systematic. 
Table_6.pdf [41 KiB] HiDef png [68 KiB] Thumbnail [10 KiB] tex code 

Production ratio $ R_{\Lambda ^+_ c / D ^0 } $ as a function of $ p_{\mathrm{ T}} $ in the forward and backward rapidity regions. The first uncertainty is statistical and the second is systematic. 
Table_7.pdf [44 KiB] HiDef png [228 KiB] Thumbnail [33 KiB] tex code 

Production ratio $ R_{\Lambda ^+_ c / D ^0 } $ as a function of $y^*$ for $2< p_{\mathrm{ T}} <10 {\mathrm{\,GeV\!/}c} $. The first uncertainty is statistical and the second is systematic. 
Table_8.pdf [42 KiB] HiDef png [170 KiB] Thumbnail [24 KiB] tex code 
Created on 09 December 2018.Citation count from INSPIRE on 18 December 2018.