Measurement of D-meson production at mid-rapidity in pp collisions at $\mathbf{\sqrt{s}=7}$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Eur.Phys.J.C 77 (2017) 550, 2017.
Inspire Record 1511870 DOI 10.17182/hepdata.78907

The production cross sections of the prompt charmed mesons ${\rm D^0}$, ${\rm D^+}$, ${\rm D^{*+}}$ and ${\rm D_s^+}$ were measured at mid-rapidity in proton-proton collisions at a centre-of-mass energy $\sqrt{s}=7$ TeV with the ALICE detector at the Large Hadron Collider (LHC). D mesons were reconstructed from their decays ${\rm D}^0 \to {\rm K}^-\pi^+$, ${\rm D}^+\to {\rm K}^-\pi^+\pi^+$, ${\rm D}^{*+} \to {\rm D}^0 \pi^+$, ${\rm D_s^{+}\to \phi\pi^+\to K^-K^+\pi^+}$, and their charge conjugates. With respect to previous measurements in the same rapidity region, the coverage in transverse momentum ($p_{\rm T}$) is extended and the uncertainties are reduced by a factor of about two. The accuracy on the estimated total $\rm c\overline c$ production cross section is likewise improved. The measured $p_{\rm T}$-differential cross sections are compared with the results of three perturbative QCD calculations.

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First measurement of $\Xi_{\rm c}^0$ production in pp collisions at $\mathbf{\sqrt{s}}$ = 7 TeV

The ALICE collaboration Acharya, S. ; Adamova, Dagmar ; Adolfsson, Jonatan ; et al.
Phys.Lett.B 781 (2018) 8-19, 2018.
Inspire Record 1642729 DOI 10.17182/hepdata.83354

The production of the charm-strange baryon $\Xi_{\rm c}^0$ is measured for the first time at the LHC via its semileptonic decay into e$^+\Xi^-\nu_{\rm e}$ in pp collisions at $\sqrt{s}=7$ TeV with the ALICE detector. The transverse momentum ($p_{\rm T}$) differential cross section multiplied by the branching ratio is presented in the interval 1 $<$ $p_{\rm T}$ $<$ 8 GeV/$c$ at mid-rapidity, $|y|$ $<$ 0.5. The transverse momentum dependence of the $\Xi_{\rm c}^0$ baryon production relative to the D$^0$ meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross-section ratio.

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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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Suppression of $\Lambda(1520)$ resonance production in central Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Torales - Acosta, Fernando ; Adamova, Dagmar ; et al.
Phys.Rev.C 99 (2019) 024905, 2019.
Inspire Record 1672806 DOI 10.17182/hepdata.84284

The production yield of the $\Lambda(1520)$ baryon resonance is measured at mid-rapidity in Pb-Pb collisions at $\sqrt{s_{\rm NN}}$ = 2.76 TeV with the ALICE detector at the LHC. The measurement is performed in the $\Lambda(1520)\rightarrow {\rm pK}^{-}$ (and charge conjugate) hadronic decay channel as a function of the transverse momentum ($p_{\rm T}$) and collision centrality. The $p_{\rm T}$-integrated production rate of $\Lambda(1520)$ relative to $\Lambda$ in central collisions is suppressed by about a factor of 2 with respect to peripheral collisions. This is the first observation of the suppression of a baryonic resonance at LHC and the first evidence of $\Lambda(1520)$ suppression in heavy-ion collisions. The measured $\Lambda(1520)/\Lambda$ ratio in central collisions is smaller than the value predicted by the statistical hadronisation model calculations. The shape of the measured $p_{\rm T}$ distribution and the centrality dependence of the suppression are reproduced by the EPOS3 Monte Carlo event generator. The measurement adds further support to the formation of a dense hadronic phase in the final stages of the evolution of the fireball created in heavy-ion collisions, lasting long enough to cause a significant reduction in the observable yield of short-lived resonances.

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Production of $\pi^0$ and $\eta$ mesons up to high transverse momentum in pp collisions at 2.76 TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Eur.Phys.J.C 77 (2017) 339, 2017.
Inspire Record 1512110 DOI 10.17182/hepdata.77976

The invariant differential cross sections for inclusive $\pi^{0}$ and $\eta$ mesons at midrapidity were measured in pp collisions at $\sqrt{s}=2.76$ TeV for transverse momenta $0.4<p_{\rm T}<40$ GeV/$c$ and $0.6<p_{\rm T}<20$ GeV/$c$, respectively, using the ALICE detector. This large range in $p_{\rm T}$ was achieved by combining various analysis techniques and different triggers involving the electromagnetic calorimeter (EMCal). In particular, a new single-cluster, shower-shape based method was developed for the identification of high-$p_{\rm T}$ neutral pions, which exploits that the showers originating from their decay photons overlap in the EMCal. The measured cross sections are found to exhibit a similar power-law behavior with an exponent of about $6.3$. Next-to-leading-order perturbative QCD calculations differ from the measured cross sections by about $30$% for the $\pi^0$, and between $30$-$50$% for the $\eta$ meson, while generator-level simulations with PYTHIA 8.2 describe the data to better than $10$-$30$%, except at $p_{\rm T}<1$ GeV/$c$. The new data can therefore be used to further improve the theoretical description of $\pi^{0}$ and $\eta$ meson production.

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Neutral pion and $\eta$ meson production in p-Pb collisions at $\mathbf{\sqrt{s_{\rm NN}}} = 5.02$ TeV

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adolfsson, Jonatan ; et al.
Eur.Phys.J.C 78 (2018) 624, 2018.
Inspire Record 1649235 DOI 10.17182/hepdata.83700

Neutral pion and $\eta$ meson invariant differential yields were measured in non-single diffractive p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE experiment at the CERN LHC. The analysis combines results from three complementary photon measurements, utilizing the PHOS and EMCal calorimeters and the Photon Conversion Method. The invariant differential yields of $\pi^0$ and $\eta$ meson inclusive production are measured near mid-rapidity in a broad transverse momentum range of $0.3<p_{\rm T}< 20$ GeV/$c$ and $0.7<p_{\rm T}<20$ GeV/$c$, respectively. The measured $\eta$/$\pi^{0}$ ratio increases with $p_{\rm T}$ and saturates for $p_{\rm T} > 4$ GeV/$c$ at $0.483\pm 0.015_{\rm stat}\pm 0.015_{\rm sys}$. A deviation from $m_{\rm T}$ scaling is observed for $p_{\rm T}<2$ GeV/$c$. The measured $\eta$/$\pi^{0}$ ratio is consistent with previous measurements from proton-nucleus and pp collisions over the full $p_{\rm T}$ range. The measured $\eta$/$\pi^{0}$ ratio at high $p_{\rm T}$ also agrees within uncertainties with measurements from nucleus-nucleus collisions. The $\pi^0$ and $\eta$ yields in p-Pb relative to the scaled pp interpolated reference, $R_{\rm pPb}$, are presented for $0.3<p_{\rm T}<20$ GeV/$c$ and $0.7<p_{\rm T}< 20$ GeV/$c$, respectively. The results are compared with theoretical model calculations. The values of $R_{\rm pPb}$ are consistent with unity for transverse momenta above 2 GeV/$c$. These results support the interpretation that the suppressed yield of neutral mesons measured in Pb-Pb collisions at LHC energies is due to parton energy loss in the hot QCD medium.

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Production of inclusive $\Upsilon$(1S) and $\Upsilon$(2S) in p-Pb collisions at $\mathbf{\sqrt{s_{{\rm NN}}} = 5.02}$ TeV

The ALICE collaboration Abelev, Betty Bezverkhny ; Adam, Jaroslav ; Adamova, Dagmar ; et al.
Phys.Lett.B 740 (2015) 105-117, 2015.
Inspire Record 1321022 DOI 10.17182/hepdata.66344

We report on the production of inclusive $\Upsilon$(1S) and $\Upsilon$(2S) in p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV at the LHC. The measurement is performed with the ALICE detector at backward ($-4.46< y_{{\rm cms}}<-2.96$) and forward ($2.03< y_{{\rm cms}}<3.53$) rapidity down to zero transverse momentum. The production cross sections of the $\Upsilon$(1S) and $\Upsilon$(2S) are presented, as well as the nuclear modification factor and the ratio of the forward to backward yields of $\Upsilon$(1S). A suppression of the inclusive $\Upsilon$(1S) yield in p-Pb collisions with respect to the yield from pp collisions scaled by the number of binary nucleon-nucleon collisions is observed at forward rapidity but not at backward rapidity. The results are compared to theoretical model calculations including nuclear shadowing or partonic energy loss effects.

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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 $\mathbf{\psi}$(2S) suppression in p-Pb collisions at $\mathbf{\sqrt{{\textit s}_{\rm NN}}}$ = 5.02 TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
JHEP 06 (2016) 050, 2016.
Inspire Record 1426826 DOI 10.17182/hepdata.73306

The inclusive production of the $\psi$(2S) charmonium state was studied as a function of centrality in p-Pb collisions at the nucleon-nucleon center of mass energy $\sqrt{s_{\rm NN}}$ = 5.02 TeV at the CERN LHC. The measurement was performed with the ALICE detector in the center of mass rapidity ranges $-4.46<y_{\rm cms}<-2.96$ and $2.03<y_{\rm cms}<3.53$, down to zero transverse momentum, by reconstructing the $\psi$(2S) decay to a muon pair. The $\psi$(2S) production cross section $\sigma_{\psi(\rm 2S)}$ is presented as a function of the collision centrality, which is estimated through the energy deposited in forward rapidity calorimeters. The relative strength of nuclear effects on the $\psi$(2S) and on the corresponding 1S charmonium state J/$\psi$ is then studied by means of the double ratio of cross sections $[\sigma_{\psi(\rm 2S)}/\sigma_{\rm J/\psi}]_{\rm pPb}/[\sigma_{\psi(\rm 2S)}/\sigma_{\rm J/\psi}]_{\rm pp}$ between p-Pb and pp collisions, and by the values of the nuclear modification factors for the two charmonium states. The results show a large suppression of $\psi$(2S) production relative to the J/$\psi$ at backward (negative) rapidity, corresponding to the flight direction of the Pb-nucleus, while at forward (positive) rapidity the suppressions of the two states are comparable. Finally, comparisons to results from lower energy experiments and to available theoretical models are presented.

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Measurement of charged jet production cross sections and nuclear modification in p-Pb collisions at $\sqrt{s_\rm{NN}} = 5.02$ TeV

The ALICE collaboration Adam, Jaroslav ; Adamova, Dagmar ; Aggarwal, Madan Mohan ; et al.
Phys.Lett.B 749 (2015) 68-81, 2015.
Inspire Record 1346963 DOI 10.17182/hepdata.68911

Charged jet production cross sections in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV measured with the ALICE detector at the LHC are presented. Using the anti-$k_{\rm T}$ algorithm, jets have been reconstructed in the central rapidity region from charged particles with resolution parameters $R = 0.2$ and $R = 0.4$. The reconstructed jets have been corrected for detector effects and the underlying event background. To calculate the nuclear modification factor, $R_{\rm pPb}$, of charged jets in p-Pb collisions, a pp reference was constructed by scaling previously measured charged jet spectra at $\sqrt{s} = 7$ TeV. In the transverse momentum range $20 \le p_{\rm T,ch\ jet} \le 120$ GeV/$c$, $R_{\rm pPb}$ is found to be consistent with unity, indicating the absence of strong nuclear matter effects on jet production. Major modifications to the radial jet structure are probed via the ratio of jet production cross sections reconstructed with the two different resolution parameters. This ratio is found to be similar to the measurement in pp collisions at $\sqrt{s} = 7$ TeV and to the expectations from PYTHIA pp simulations and NLO pQCD calculations at $\sqrt{s_{\rm NN}} = 5.02$ TeV.

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