D_s meson production at central rapidity in proton--proton collisions at sqrt(s) = 7 TeV

The ALICE collaboration Abelev, Betty ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Lett.B 718 (2012) 279-294, 2012.
Inspire Record 1126963 DOI 10.17182/hepdata.62306

The $p_{\rm T}$-differential inclusive production cross section of the prompt charm-strange meson $\rm D_s^+$ in the rapidity range $|y|<0.5$ was measured in proton-proton collisions at $\sqrt{s}=7$ TeV at the LHC using the ALICE detector. The analysis was performed on a data sample of $2.98 \times 10^8$ events collected with a minimum-bias trigger. The corresponding integrated luminosity is $L_{\rm int}=4.8$/nb. Reconstructing the decay ${\rm D_s^{+}\to \phi\pi^+}$, with $\phi\to {\rm K}^-{\rm K}^+$, and its charge conjugate, about 480 ${\rm D_s^{\pm}}$ mesons were counted, after selection cuts, in the transverse momentum range $2<p_{\rm T}<12$ Gev/$c$. The results are compared with predictions from models based on perturbative QCD. The ratios of the cross sections of four D meson species (namely ${\rm D^0}$, ${\rm D^+}$, ${\rm D^{*+}}$ and ${\rm D_s^+}$) were determined both as a function of $p_{\rm T}$ and integrated over $p_{\rm T}$ after extrapolating to full $p_{\rm T}$ range, together with the strangeness suppression factor in charm fragmentation. The obtained values are found to be compatible within uncertainties with those measured by other experiments in $\rm e^+e^-$, ep and pp interactions at various centre-of-mass energies.

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Version 2
Production of light nuclei and anti-nuclei in pp and Pb-Pb collisions at LHC energies

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Rev.C 93 (2016) 024917, 2016.
Inspire Record 1380491 DOI 10.17182/hepdata.72547

The production of (anti-)deuteron and (anti-)$^{3}$He nuclei in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV has been studied using the ALICE detector at the LHC. The spectra exhibit a significant hardening with increasing centrality. Combined blast-wave fits of several particles support the interpretation that this behavior is caused by an increase of radial flow. The integrated particle yields are discussed in the context of coalescence and thermal-statistical model expectations. The particle ratios, $^3$He/d and $^3$He/p, in Pb-Pb collisions are found to be in agreement with a common chemical freeze-out temperature of $T_{\rm chem} \approx 156$ MeV. These ratios do not vary with centrality which is in agreement with the thermal-statistical model. In a coalescence approach, it excludes models in which nucleus production is proportional to the particle multiplicity and favors those in which it is proportional to the particle density instead. In addition, the observation of 31 anti-tritons in Pb-Pb collisions is reported. For comparison, the deuteron spectrum in pp collisions at $\sqrt{s} = 7$ TeV is also presented. While the p/$\pi$ ratio is similar in pp and Pb-Pb collisions, the d/p ratio in pp collisions is found to be lower by a factor of 2.2 than in Pb-Pb collisions.

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Transverse momentum dependence of D-meson production in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
JHEP 03 (2016) 081, 2016.
Inspire Record 1394580 DOI 10.17182/hepdata.72510

The production of prompt charmed mesons D$^0$, D$^+$ and D$^{*+}$, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at the centre-of-mass energy per nucleon pair, $\sqrt{s_{\rm NN}}$, of 2.76 TeV. The production yields for rapidity $|y|<0.5$ are presented as a function of transverse momentum, $p_{\rm T}$, in the interval 1-36 GeV/$c$ for the centrality class 0-10% and in the interval 1-16 GeV/$c$ for the centrality class 30-50%. The nuclear modification factor $R_{\rm AA}$ was computed using a proton-proton reference at $\sqrt{s} = 2.76$ TeV, based on measurements at $\sqrt{s} = 7$ TeV and on theoretical calculations. A maximum suppression by a factor of 5-6 with respect to binary-scaled pp yields is observed for the most central collisions at $p_{\rm T}$ of about 10 GeV/$c$. A suppression by a factor of about 2-3 persists at the highest $p_{\rm T}$ covered by the measurements. At low $p_{\rm T}$ (1-3 GeV/$c$), the $R_{\rm AA}$ has large uncertainties that span the range 0.35 (factor of about 3 suppression) to 1 (no suppression). In all $p_{\rm T}$ intervals, the $R_{\rm AA}$ is larger in the 30-50% centrality class compared to central collisions. The D-meson $R_{\rm AA}$ is also compared with that of charged pions and, at large $p_{\rm T}$, charged hadrons, and with model calculations.

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Measurement of D$_s^+$ production and nuclear modification factor in Pb-Pb collisions at $\sqrt{s_{\rm NN}}=2.76$ TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
JHEP 03 (2016) 082, 2016.
Inspire Record 1394675 DOI 10.17182/hepdata.71277

The production of prompt D$_s^+$ mesons was measured for the first time in collisions of heavy nuclei with the ALICE detector at the LHC. The analysis was performed on a data sample of Pb-Pb collisions at a centre-of-mass energy per nucleon pair, $\sqrt{s_{\rm NN}}$, of 2.76 TeV in two different centrality classes, namely 0-10% and 20-50%. D$_s^+$ mesons and their antiparticles were reconstructed at mid-rapidity from their hadronic decay channel D$_s^+\rightarrow\phi\pi^+$, with $\phi\rightarrow$K$^-$K$^+$, in the transverse momentum intervals $4< p_{\rm T}<12$ GeV/$c$ and $6< p_{\rm T}<12$ GeV/$c$ for the 0-10% and 20-50% centrality classes, respectively. The nuclear modification factor $R_{\rm AA}$ was computed by comparing the $p_{\rm T}$-differential production yields in Pb-Pb collisions to those in proton-proton (pp) collisions at the same energy. This pp reference was obtained using the cross section measured at $\sqrt{s}= 7$ TeV and scaled to $\sqrt{s}= 2.76$ TeV. The $R_{\rm AA}$ of D$_s^+$ mesons was compared to that of non-strange D mesons in the 10% most central Pb-Pb collisions. At high $p_{\rm T}$ ($8< p_{\rm T}<12$ GeV/$c$) a suppression of the D$_s^+$-meson yield by a factor of about three, compatible within uncertainties with that of non-strange D mesons, is observed. At lower $p_{\rm T}$ ($4< p_{\rm T}<8$ GeV/$c$) the values of the D$_s^+$-meson $R_{\rm AA}$ are larger than those of non-strange D mesons, although compatible within uncertainties. The production ratios D$_s^+$/D$^0$ and D$_s^+$\D$^+$ were also measured in Pb-Pb collisions and compared to their values in proton-proton collisions.

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Centrality dependence of high-$p_{\rm T}$ D meson suppression in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
JHEP 11 (2015) 205, 2015.
Inspire Record 1377363 DOI 10.17182/hepdata.39350

The nuclear modification factor, $R_{\rm AA}$, of the prompt charmed mesons ${\rm D^0}$, ${\rm D^+}$ and ${\rm D^{*+}}$, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at a centre-of-mass energy $\sqrt{s_{\rm NN}} = 2.76$ TeV in two transverse momentum intervals, $5<p_{\rm T}<8$ GeV/$c$ and $8<p_{\rm T}<16$ GeV/$c$, and in six collision centrality classes. The $R_{\rm AA}$ shows a maximum suppression of a factor of 5-6 in the 10% most central collisions. The suppression and its centrality dependence are compatible within uncertainties with those of charged pions. A comparison with the $R_{\rm AA}$ of non-prompt ${\rm J}/\psi$ from B meson decays, measured by the CMS Collaboration, hints at a larger suppression of D mesons in the most central collisions.

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Measurement of prompt D-meson production in p-Pb collisions at sqrt(sNN) = 5.02 TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.Lett. 113 (2014) 232301, 2015.
Inspire Record 1296081 DOI 10.17182/hepdata.63866

The $p_{\rm T}$-differential production cross sections of the prompt charmed mesons $D^0$, $D^+$, $D^{*+}$ and $D_{\rm s}^{+}$ and their charge conjugate in the rapidity interval $-0.96 < y_{\rm cms} < 0.04$ were measured in p-Pb collisions at a centre-of-mass energy $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE detector at the LHC. The nuclear modification factor $R_{\rm pPb}$, quantifying the D-meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15-20% uncertainties with unity in the transverse momentum interval $1 < p_{\rm T} < 24$ GeV/$c$. No significant difference among the $R_{\rm pPb}$ of the four D-meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects induced by hot partonic matter.

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Measurement of charm production at central rapidity in proton-proton collisions at sqrt(s) = 2.76 TeV

The ALICE collaboration Abelev, Betty ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
JHEP 07 (2012) 191, 2012.
Inspire Record 1115187 DOI 10.17182/hepdata.62077

The $p_{\rm T}$-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D$^0$, D$^+$, and D$^{*+}$ in the rapidity range $|y|<0.5$, and for transverse momentum $1< p_{\rm T} <12$ GeV/$c$, were measured in proton-proton collisions at $\sqrt{s} = 2.76$ TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D$^0 \rightarrow $K$\pi$, D$^+ \rightarrow $K$\pi\pi$, D$^{*+} \rightarrow $D$^0\pi$, and their charge conjugates, and was performed on a $L_{\rm int} = 1.1$ nb$^{-1}$ event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at $\sqrt{s} = 2.76$ TeV and at 7 TeV was evaluated by extrapolating to the full phase space the $p_{\rm T}$-differential production cross sections at $\sqrt{s} = 2.76$ TeV and our previous measurements at $\sqrt{s} = 7$ TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.

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Azimuthal anisotropy of D meson production in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Rev.C 90 (2014) 034904, 2014.
Inspire Record 1294938 DOI 10.17182/hepdata.63499

The production of the prompt charmed mesons $D^0$, $D^+$ and $D^{*+}$ relative to the reaction plane was measured in Pb-Pb collisions at a centre-of-mass energy per nucleon-nucleon collision of $\sqrt{s_{\rm NN}} = 2.76$ TeV with the ALICE detector at the LHC. D mesons were reconstructed via their hadronic decays at central rapidity in the transverse momentum ($p_{\rm T}$) interval of 2-16 GeV/$c$. The azimuthal anisotropy is quantified in terms of the second coefficient $v_2$ in a Fourier expansion of the D meson azimuthal distribution, and in terms of the nuclear modification factor $R_{\rm AA}$, measured in the direction of the reaction plane and orthogonal to it. The $v_2$ coefficient was measured with three different methods and in three centrality classes in the interval 0-50%. A positive $v_2$ is observed in mid-central collisions (30-50% centrality class), with an mean value of $0.204_{-0.036}^{+0.099}$ (tot.unc.) in the interval $2 < p_{\rm T} < 6$ GeV/$c$, which decreases towards more central collisions (10-30% and 0-10% classes). The positive $v_2$ is also reflected in the nuclear modification factor, which shows a stronger suppression in the direction orthogonal to the reaction plane for mid-central collisions. The measurements are compared to theoretical calculations of charm quark transport and energy loss in high-density strongly-interacting matter at high temperature. The models that include substantial elastic interactions with an expanding medium provide a good description of the observed anisotropy. However, they are challenged to simultaneously describe the strong suppression of high-$p_{\rm T}$ yield of D mesons in central collisions and their azimuthal anisotropy in non-central collisions.

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Suppression of high transverse momentum D mesons in central Pb--Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV

The ALICE collaboration Abelev, Betty ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
JHEP 09 (2012) 112, 2012.
Inspire Record 1093488 DOI 10.17182/hepdata.60103

The production of the prompt charm mesons $D^0$, $D^+$, $D^{*+}$, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at the LHC, at a centre-of-mass energy $\sqrt{s_{NN}}=2.76$ TeV per nucleon--nucleon collision. The $p_{\rm T}$-differential production yields in the range $2<p_{\rm T}<16$ GeV/c at central rapidity, $|y|<0.5$, were used to calculate the nuclear modification factor $R_{AA}$ with respect to a proton-proton reference obtained from the cross section measured at $\sqrt{s}=7$ TeV and scaled to $\sqrt{s}=2.76$ TeV. For the three meson species, $R_{AA}$ shows a suppression by a factor 3-4, for transverse momenta larger than 5 GeV/c in the 20% most central collisions. The suppression is reduced for peripheral collisions.

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Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Rev.D 85 (2012) 052005, 2012.
Inspire Record 1082009 DOI 10.17182/hepdata.58635

This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.

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