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The ALICE Collaboration at the LHC reports measurement of the inclusive production cross section of electrons from semi-leptonic decays of beauty hadrons with rapidity |y|<0.8 and transverse momentum 1<pT<10 GeV/c , in pp collisions at s=2.76 TeV . Electrons not originating from semi-electronic decay of beauty hadrons are suppressed using the impact parameter of the corresponding tracks. The production cross section of beauty decay electrons is compared to the result obtained with an alternative method which uses the distribution of the azimuthal angle between heavy-flavour decay electrons and charged hadrons. Perturbative QCD predictions agree with the measured cross section within the experimental and theoretical uncertainties. The integrated visible cross section, σb→e=3.47±0.40(stat)−1.33+1.12(sys)±0.07(norm) μb , was extrapolated to full phase space using Fixed Order plus Next-to-Leading Log (FONLL) calculations to obtain the total bb¯ production cross section, σbb¯=130±15.1(stat)−49.8+42.1(sys)−3.1+3.4(extr)±2.5(norm)±4.4(BR) μb .
Azimuthal correlation distribution between heavy-flavour decay electrons and charged hadrons, scaled by the number of electrons in minimum bias triggered events in the electron transverse momentum range 1.5-2.5 GeV/$c$.
Azimuthal correlation distribution between heavy-flavour decay electrons and charged hadrons, scaled by the number of electrons in EMCal triggered events in the electron transverse momentum range 4.5-6 GeV/$c$.
Relative beauty contribution to the heavy-flavour electron yield obtained with the method based on the track impact parameter.
pT-differential inclusive muon $v_{2}$ extracted with scalar product method.
pT-differential inclusive muon $v_{2}$ extracted with two-particle $Q$ cumulants method.
pT-differential inclusive muon $v_{2}$ extracted with scalar product method.
Invariant yields of neutral pions at midrapidity in the transverse momentum range $0.6 < p_\mathrm{T}< 12\,{\mathrm \mathrm{GeV}}/$ c measured in Pb–Pb collisions at $\sqrt{s_{\mathrm {NN}}}= 2.76\,{\mathrm {\,}}\mathrm{TeV}$ are presented for six centrality classes. The pp reference spectrum was measured in the range $0.4 < p_\mathrm{T}< 10\,{\mathrm {\,}}\mathrm{GeV}/$ c at the same center-of-mass energy. The nuclear modification factor, $R_\mathrm{{AA}}$ , shows a suppression of neutral pions in central Pb–Pb collisions by a factor of up to about $8{-}10$ for $5 \lesssim p_\mathrm{T}\lesssim 7\,{\mathrm \mathrm{GeV}}/$ c. The presented measurements are compared with results at lower center-of-mass energies and with theoretical calculations.
Invariant differential yields of PI0 produced in inelastic pp collisions at center-of-mass energy 2.76 TeV.
Invariant differential cross section of PI0 produced in inelastic pp collisions at center-of-mass energy 2.76 TeV, the uncertainty of \sigma_{inel} of 3.9% is not included in the systematic error.
Invariant differential yields of PI0 produced in 0-5% central inelastic PbPb collisions at center-of-mass energy per nucleon 2.76 TeV.
On 23rd November 2009, during the early commissioning of the CERN Large Hadron Collider (LHC), two counter-rotating proton bunches were circulated for the first time concurrently in the machine, at the LHC injection energy of 450 GeV per beam. Although the proton intensity was very low, with only one pilot bunch per beam, and no systematic attempt was made to optimize the collision optics, all LHC experiments reported a number of collision candidates. In the ALICE experiment, the collision region was centred very well in both the longitudinal and transverse directions and 284 events were recorded in coincidence with the two passing proton bunches. The events were immediately reconstructed and analyzed both online and offline. We have used these events to measure the pseudorapidity density of charged primary particles in the central region. In the range |eta| < 0.5, we obtain dNch/deta = 3.10 +- 0.13 (stat.) +- 0.22 (syst.) for all inelastic interactions, and dNch/deta = 3.51 +- 0.15 (stat.) +- 0.25 (syst.) for non-single diffractive interactions. These results are consistent with previous measurements in proton--antiproton interactions at the same centre-of-mass energy at the CERN SppS collider. They also illustrate the excellent functioning and rapid progress of the LHC accelerator, and of both the hardware and software of the ALICE experiment, in this early start-up phase.
Pseudorapidity dependence of DN/DETARAP in Inelastic (INEL) and Non-Single-Diffractive (NSD) collisions. Note that the plot in the paper shows only statistical errors.
Pseudorapidity density for |ETARAP|<0.5 for Inelastic (INEL) and Non-Single-Diffractive (NSD) collisions.
We report on the measurement of two-pion correlation functions from pp collisions at sqrt(s)=900 GeV performed by the ALICE experiment at the Large Hadron Collider. Our analysis shows an increase of the HBT radius with increasing event multiplicity, in line with other measurements done in particle- and nuclear collisions. Conversely, the strong decrease of the radius with increasing transverse momentum, as observed at RHIC and at Tevatron, is not manifest in our data.
Two-particle correlation functions for like-sign and unlike sign pion pairs.
Two-particle correlation functions for like-sign and unlike sign pion pairs.
Two-particle correlation functions for like-sign and unlike sign pion pairs.
The ratio of the yields of antiprotons to protons in pp collisions has been measured by the ALICE experiment at $\sqrt{s} = 0.9$ and $7$~TeV during the initial running periods of the Large Hadron Collider(LHC). The measurement covers the transverse momentum interval $0.45 < p_{\rm{t}} < 1.05$~GeV/$c$ and rapidity $|y| < 0.5$. The ratio is measured to be $R_{|y| < 0.5} = 0.957 \pm 0.006 (stat.) \pm 0.014 (syst.)$ at $0.9$~TeV and $R_{|y| < 0.5} = 0.991 \pm 0.005 (stat.) \pm 0.014 (syst.)$ at $7$~TeV and it is independent of both rapidity and transverse momentum. The results are consistent with the conventional model of baryon-number transport and set stringent limits on any additional contributions to baryon-number transfer over very large rapidity intervals in pp collisions.
The PT dependence of the pbar/p ratio for the central rapidity region ABS(YRAP)<0.5.
The central rapidity pbar/p ratio as a function of the rapidity interval Ybeam-Ybaryon and centre-of-mass energy. As well as the present ALICE measurements this table also lists the values from other experiments (see the text of the paper for details).
Double differential J/PSI cross section from the di-electron channel as a function of transverse momentum, the first error is statistical, the first systematic error is the correlated one, the second is the non-correlated one. The last four columns are the errors considering. a +1 polarization in the Collins-Soper frame, a -1 polarization in the Collins-Soper frame, a +1 polarization in the Helicity frame and a -1 polarization in the Helicity frame, respectively.
Differential J/PSI cross section from the di-muon channel as a function of transverse momentum, the first error is statistical, the first systematic error is the correlated one, the second is the non-correlated one. The last four columns are the errors (in MUB/GEV) considering a +1 polarization in the Collins-Soper frame, a -1 polarization in the Collins-Soper frame, a +1 polarization in the Helicity frame and a -1 polarization in the Helicity frame, respectively.
Differential J/PSI cross section from the di-electron and di-muon channel as a function of rapidity, the first error is statistical, the first systematic error is the correlated one, the second is the non-correlated one. The last four columns are the errors (in MUB/GEV) considering. Data in the first point of this table updated from the erratum.
Amplitudes of the VnDelta harmonics versus n for events with trigger particles having transverse momenta in the range 2-2.5 GeV and associated particles in the range 1.5-2.0 GeV for two centrality classes 0-2% and 2-10%. Note that in the paper the data are plotted multiplied by 100.
Amplitudes of the VnDelta harmonics versus n for events with trigger particles having transverse momenta in the range 2-2.5 GeV and associated particles in the range 1.5-2.0 GeV for three centrality classes 10-20%, 20-30% and 40-50%. Note that in the paper the data are plotted multiplied by 100.
Amplitudes of the VnDelta harmonics versus n for events with trigger particles having transverse momenta in the range 8-15 GeV and associated particles in the range 6-8 GeV for two centrality classes 40-50% and 0-20%. Note that in the paper the data are plotted multiplied by 100.
The production of muons from heavy flavour decays is measured at forward rapidity in proton--proton collisions at \sqrt(s) = 7 TeV collected with the ALICE experiment at the LHC. The analysis is carried out on a data sample corresponding to an integrated luminosity L_{int} = 16.5 nb^{-1}. The transverse momentum and rapidity differential production cross sections of muons from heavy flavour decays are measured in the rapidity range 2.5 < y < 4, over the transverse momentum range 2 < p_{t} < 12 GeV/c. The results are compared to predictions based on perturbative QCD calculations.
pT-differential production cross section of muons from heavy flavour decays, in the rapidity range 2.5<y<4.
y-differential production cross section of muons from heavy flavour decays, in the range 2<pT<12 GeV/C.
pT-differential production cross section of muons from heavy flavour decays, in the rapidity range 2.5<y<2.8.
The first measurement of two-pion Bose--Einstein correlations in central PbPb collisions at $\sqrt{s_{NN}} = 2.76$ TeV at the Large Hadron Collider is presented. We observe a growing trend with energy now not only for the longitudinal and the outward but also for the sideward pion source radius. The pion homogeneity volume and the decoupling time are significantly larger than those measured at RHIC.
Projections of the correlation function C.
Projections of the correlation function C.
Projections of the correlation function C.
The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y|<0.8) in the transverse momentum range 1<p_T<8 GeV/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy s=7 TeV using an integrated luminosity of 2.2 nb^-^1. Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark-antiquark pairs.
Double differential cross section for charm and beauty electron production as a function of transverse momentum. The systematic error does not include the error on the Luminosity (3.5%).
Femtoscopic radii as a function od pair transverse momentum $k_{\rm T}$ for seven centrality ranges.
Femtoscopic radii as a function od pair transverse momentum $k_{\rm T}$ for seven centrality ranges.
Femtoscopic radii as a function od pair transverse momentum $k_{\rm T}$ for seven centrality ranges.
We report measurements of the primary charged-particle pseudorapidity density and transverse momentum distributions in p-Pb collisions at sNN=5.02TeV and investigate their correlation with experimental observables sensitive to the centrality of the collision. Centrality classes are defined by using different event-activity estimators, i.e., charged-particle multiplicities measured in three different pseudorapidity regions as well as the energy measured at beam rapidity (zero degree). The procedures to determine the centrality, quantified by the number of participants (Npart) or the number of nucleon-nucleon binary collisions (Ncoll) are described. We show that, in contrast to Pb-Pb collisions, in p-Pb collisions large multiplicity fluctuations together with the small range of participants available generate a dynamical bias in centrality classes based on particle multiplicity. We propose to use the zero-degree energy, which we expect not to introduce a dynamical bias, as an alternative event-centrality estimator. Based on zero-degree energy-centrality classes, the Npart dependence of particle production is studied. Under the assumption that the multiplicity measured in the Pb-going rapidity region scales with the number of Pb participants, an approximate independence of the multiplicity per participating nucleon measured at mid-rapidity of the number of participating nucleons is observed. Furthermore, at high-pT the p-Pb spectra are found to be consistent with the pp spectra scaled by Ncoll for all centrality classes. Our results represent valuable input for the study of the event-activity dependence of hard probes in p-Pb collisions and, hence, help to establish baselines for the interpretation of the Pb-Pb data.
dNdeta CL1.
dNdeta V0M.
dNdeta V0A.
The ALICE measurement of KS0 and Λ production at midrapidity in Pb-Pb collisions at sNN=2.76 TeV is presented. The transverse momentum (pT) spectra are shown for several collision centrality intervals and in the pT range from 0.4 GeV/c (0.6 GeV/c for Λ) to 12 GeV/c. The pT dependence of the Λ/KS0 ratios exhibits maxima in the vicinity of 3 GeV/c, and the positions of the maxima shift towards higher pT with increasing collision centrality. The magnitude of these maxima increases by almost a factor of three between most peripheral and most central Pb-Pb collisions. This baryon excess at intermediate pT is not observed in pp interactions at s=0.9 TeV and at s=7 TeV. Qualitatively, the baryon enhancement in heavy-ion collisions is expected from radial flow. However, the measured pT spectra above 2 GeV/c progressively decouple from hydrodynamical-model calculations. For higher values of pT, models that incorporate the influence of the medium on the fragmentation and hadronization processes describe qualitatively the pT dependence of the Λ/KS0 ratio.
pT spectra of K0Short in the rapidity range -0.5<y<0.5 in the centrality interval 0.0-5.0%.
pT spectra of K0Short in the rapidity range -0.5<y<0.5 in the centrality interval 5.0-10.0%.
pT spectra of K0Short in the rapidity range -0.5<y<0.5 in the centrality interval 10.0-20.0%.
pT-differential invariant yield of pion+ and pion- for centrality 0-5%. These data are also available from http://hepdata.cedar.ac.uk/view/ins1126966.
pT-differential invariant yield of pion+ and pion- for centrality 5-10%.
pT-differential invariant yield of pion+ and pion- for centrality 10-20%.
The normalized differential primary charged particle cross sections measured at 0.9, 2.76 and 7 TeV centre-of- mass energies. Additional systematic error for 0.9 TeV data: +5.1% -4.0%. Additional systematic error for 2.76 TeV data: +1.9% -1.9%. Additional systematic error for 7.0 TeV data: +3.6% -3.6%.
The ratios of differential cross sections of charged particles at different collisions energies.
The constructed reference P-P spectra for comparison with PB-PB and p-PB spectra.
The ratios of yields of anti-baryons to baryons probes the mechanisms of baryon-number transport. Results for , , and in pp collisions at , measured with the ALICE detector at the LHC, are reported. Within the experimental uncertainties and ranges covered by our measurement, these ratios are independent of rapidity, transverse momentum and multiplicity for all measured energies. The results are compared to expectations from event generators, such as PYTHIA and HIJING/B, that are used to model the particle production in pp collisions. The energy dependence of , , and , reaching values compatible with unity for , complement the earlier measurement of ALICE. These dependencies can be described by exchanges with the Regge-trajectory intercept of , which are suppressed with increasing rapidity interval Δy. Any significant contribution of an exchange not suppressed at large Δy (reached at LHC energies) is disfavoured.
The pbar/p ratio at sqrt(s) = 2.76 TeV as a function of pT.
The pbar/p ratio at sqrt(s) = 2.76 TeV as a function of rapidity.
The LambdaBar/Lambda ratio at sqrt(s) = 0.9 TeV as a function of pT.
<p>The <inline-formula><mml:math display="inline"><mml:msub><mml:mi>p</mml:mi><mml:mi>T</mml:mi></mml:msub></mml:math></inline-formula>-differential production cross sections of the prompt charmed mesons <inline-formula><mml:math display="inline"><mml:mrow><mml:msup><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mn>0</mml:mn></mml:mrow></mml:msup></mml:mrow></mml:math></inline-formula>, <inline-formula><mml:math display="inline"><mml:msup><mml:mi>D</mml:mi><mml:mo>+</mml:mo></mml:msup></mml:math></inline-formula>, <inline-formula><mml:math display="inline"><mml:msup><mml:mi>D</mml:mi><mml:mrow><mml:mo>*</mml:mo><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math></inline-formula>, and <inline-formula><mml:math display="inline"><mml:mrow><mml:msubsup><mml:mrow><mml:mi>D</mml:mi></mml:mrow><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula> and their charge conjugate in the rapidity interval <inline-formula><mml:math display="inline"><mml:mrow><mml:mo>-</mml:mo><mml:mn>0.96</mml:mn><mml:mo><</mml:mo><mml:msub><mml:mrow><mml:mi>y</mml:mi></mml:mrow><mml:mrow><mml:mtext>cms</mml:mtext></mml:mrow></mml:msub><mml:mo><</mml:mo><mml:mn>0.04</mml:mn></mml:mrow></mml:math></inline-formula> were measured in <inline-formula><mml:math display="inline"><mml:mrow><mml:mi>p</mml:mi><mml:mtext>-</mml:mtext><mml:mi>Pb</mml:mi></mml:mrow></mml:math></inline-formula> collisions at a center-of-mass energy <inline-formula><mml:math display="inline"><mml:mrow><mml:msqrt><mml:mrow><mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mi>N</mml:mi><mml:mi>N</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>5.02</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>TeV</mml:mi></mml:mrow></mml:math></inline-formula> with the ALICE detector at the LHC. The nuclear modification factor <inline-formula><mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:mi>p</mml:mi><mml:mi>Pb</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula>, quantifying the <inline-formula><mml:math display="inline"><mml:mi>D</mml:mi></mml:math></inline-formula>-meson yield in <inline-formula><mml:math display="inline"><mml:mrow><mml:mi>p</mml:mi><mml:mtext>-</mml:mtext><mml:mi>Pb</mml:mi></mml:mrow></mml:math></inline-formula> collisions relative to the yield in <inline-formula><mml:math display="inline"><mml:mi>p</mml:mi><mml:mi>p</mml:mi></mml:math></inline-formula> collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%–20% uncertainties with unity in the transverse momentum interval <inline-formula><mml:math display="inline"><mml:mrow><mml:mn>1</mml:mn><mml:mo><</mml:mo><mml:msub><mml:mrow><mml:mi>p</mml:mi></mml:mrow><mml:mrow><mml:mi>T</mml:mi></mml:mrow></mml:msub><mml:mo><</mml:mo><mml:mn>24</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:mi>GeV</mml:mi><mml:mo stretchy="false">/</mml:mo><mml:mi>c</mml:mi></mml:mrow></mml:math></inline-formula>. No significant difference among the <inline-formula><mml:math display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>R</mml:mi></mml:mrow><mml:mrow><mml:mi>p</mml:mi><mml:mi>Pb</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math></inline-formula> of the four <inline-formula><mml:math display="inline"><mml:mi>D</mml:mi></mml:math></inline-formula>-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 <inline-formula><mml:math display="inline"><mml:mi>D</mml:mi></mml:math></inline-formula> mesons observed in Pb-Pb collisions with respect to <inline-formula><mml:math display="inline"><mml:mi>p</mml:mi><mml:mi>p</mml:mi></mml:math></inline-formula> collisions is due to strong final-state effects induced by hot partonic matter.</p>
pT-differential cross section of prompt D0 mesons measured in p-Pb collisions in the rapidity interval -0.96<y_cms<0.04.
pT-differential cross section of prompt D+ mesons measured in p-Pb collisions in the rapidity interval -0.96<y_cms<0.04.
pT-differential cross section of prompt D*+ mesons measured in p-Pb collisions in the rapidity interval -0.96<y_cms<0.04.
The ALICE experiment has measured the inclusive J/psi production in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV down to zero transverse momentum in the rapidity range 2.5 < y < 4. A suppression of the inclusive J/psi yield in Pb-Pb is observed with respect to the one measured in pp collisions scaled by the number of binary nucleon-nucleon collisions. The nuclear modification factor, integrated over the 0%-80% most central collisions, is 0.545+/-0.032(stat)+/-0.083(syst) and does not exhibit a significant dependence on the collision centrality. These features appear significantly different from measurements at lower collision energies. Models including J/psi production from charm quarks in a deconfined partonic phase can describe our data.
Jpsi Nuclear Modification Factor (Raa) measured in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV in 2.5 < y < 4 and pt > 0 GeV/c, as a function of - the average number of participating nucleons (<Npart>), - the average number of participating nucleons (<Npart,w>) weigthed by the average number of binary collisions, - the mid-rapidity charged-particle density measured at pseudo-rapidity eta = 0 dNch,w/deta|eta=0 weigthed by the average number of binary collisions.
Centrality integrated (0%-80%) inclusive Jpsi Nuclear Modification Factor (Raa) measured in Pb-Pb collisions at sqrt(sNN) = 2.76 TeV as a function of rapidity for two transverse momentum ranges.
Inclusive differential jet cross section for R=0.2 and R=0.4.
Ratio of the inclusive differential jet cross section for R=0.2 and R=0.4.
Inclusive Upsilon (1S) Nuclear Modification Factor (Raa) measured in Lead-Lead collisions at sqrt(sNN) = 2.76 TeV in 2.5 < y < 4 and pt > 0 GeV, as a function of the average number of participating nucleons (<Npart>). Data have been collected in 2011 and the integrated luminosity is ~ 70 inverse microbarn.
Inclusive Upsilon (1S) Nuclear Modification Factor (Raa) measured in Lead-Lead collisions at sqrt(sNN) = 2.76 TeV in 2.5 < y < 4 and pt > 0 GeV, as a function of the rapidity. Data have been collected in 2011 and the integrated luminosity is ~ 70 inverse microbarn.
The ALICE Collaboration has studied the inclusive production of the charmonium state ψ(2S) in proton-lead (p-Pb) collisions at the nucleon-nucleon centre of mass energy $ \sqrt{s_{\mathrm{NN}}} $ = 5.02 TeV at the CERN LHC. The measurement was performed at forward (2.03 < y$_{cms}$ < 3.53) and backward (−4.46 < y$_{cms}$ < −2.96) centre of mass rapidities, studying the decays into muon pairs. In this paper, we present the inclusive production cross sections σ$_{ψ(2S)}$, both integrated and as a function of the transverse momentum p$_{T}$, for the two y$_{cms}$ domains. The results are compared to those obtained for the 1S vector state (J/ψ), by showing the ratios between the production cross sections, as well as the double ratios [σ$_{ψ(2S)}$ /σ$_{J/ψ}$ ]$_{pPb}$ /[σ$_{ψ(2S)}$ /σ$_{J/ψ}$ ]$_{pp}$ between p-Pb and proton-proton collisions. Finally, the nuclear modification factor for inclusive ψ(2S) is evaluated and compared to the measurement of the same quantity for J/ψ and to theoretical models including parton shadowing and coherent energy loss mechanisms. The results show a significantly larger suppression of the ψ(2S) compared to that measured for J/ψ and to models. These observations represent a clear indication for sizeable final state effects on ψ(2S) production.
The cross section ratios B.R. sigma_Psi(2S)/ B.R. sigma_JPsi obtained in p-Pb and Pb-p collisions. The first uncertainty is statistical, the second one is systematic.
The double ratio [sigma(Psi(2S))/sigma(J/Psi)]_pA/[sigma(Psi(2S))/sigma(J/Psi)]_pp for p-Pb and Pb-p collisions. First uncertainty is statistical, the second one is the correlated systematic, while the third is the uncorrelated systematic.
The Psi(2S) nuclear modification factor RpA measured in pPb and Pbp collisions. The first uncertainty is statistical, the second one is the correlated systematic and the third the uncorrelated systematic.
We report on the production of inclusive ϒ (1S) and ϒ (2S) in p–Pb collisions at sNN=5.02 TeV at the LHC. The measurement is performed with the ALICE detector at backward ( −4.46<ycms<−2.96 ) and forward ( 2.03<ycms<3.53 ) rapidity down to zero transverse momentum. The production cross sections of the ϒ (1S) and ϒ (2S) are presented, as well as the nuclear modification factor and the ratio of the forward to backward yields of ϒ (1S). A suppression of the inclusive ϒ (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.
Inclusive UPSI(1S) production cross section as a function of rapidity in p-Pb collisions at sqrt(s_NN) = 5.02 TeV. The data was collected in 2013 with two beam configurations, p-Pb and Pb-p with integrated luminosities of 5.0 nb-1 and 5.8 nb-1, respectively.
Inclusive UPSI(1S) production cross section as a function of rapidity in p-Pb collisions at sqrt(s_NN) = 5.02 TeV. The data was collected in 2013 with two beam configurations, p-Pb and Pb-p with integrated luminosities of 5.0 nb-1 and 5.8 nb-1, respectively.
Inclusive UPSI(2S) production cross section as a function of rapidity in p-Pb collisions at sqrt(s_NN) = 5.02 TeV. The data was collected in 2013 with two beam configurations, p-Pb and Pb-p with integrated luminosities of 5.0 nb-1 and 5.8 nb-1, respectively.
The transverse momentum (p$_{T}$) dependence of the nuclear modification factor R$_{AA}$ and the centrality dependence of the average transverse momentum 〈p$_{T}$〉 for inclusive J/ψ have been measured with ALICE for Pb-Pb collisions at $ \sqrt{s_{\mathrm{NN}}}=2.76 $ TeV in the e+e$^{−}$ decay channel at mid-rapidity (|y| < 0.8). The 〈p$_{T}$〉 is significantly smaller than the one observed for pp collisions at the same centre-of-mass energy. Consistently, an increase of R$_{AA}$ is observed towards low p$_{T}$. These observations might be indicative of a sizable contribution of charm quark coalescence to the J/ψ production. Additionally, the fraction of non-prompt J/ψ from beauty hadron decays, f$_{B}$, has been determined in the region 1.5 < p$_{T}$ < 10 GeV/c in three centrality intervals. No significant centrality dependence of f$_{B}$ is observed. Finally, the R$_{AA}$ of non-prompt J/ψ is discussed and compared with model predictions. The nuclear modification in the region 4.5 < p$_{T}$ < 10 GeV/c is found to be stronger than predicted by most models.
The average transverse momentum $\langle p_{\rm T} \rangle$ of inclusive J/$\psi$ measured at mid-rapidity in centrality selected Pb-Pb collisions as a function of the number of participants.
The average transverse momentum squared $\langle p_{\rm T}^{2} \rangle$ of inclusive J/$\psi$ measured at mid-rapidity in centrality selected Pb-Pb collisions as a function of the number of participants.
The ratio $\langle p_{\rm T}^{2} \rangle_{\rm AA} / \langle p_{\rm T}^{2} \rangle_{\rm pp}$ of inclusive J/$\psi$ measured at mid-rapidity in centrality selected Pb-Pb collisions as a function of the number of participants.
The strength of forward-backward (FB) multiplicity correlations is measured by the ALICE detector in proton-proton (pp) collisions at $ \sqrt{s} $ = 0.9, 2.76 and 7 TeV. The measurement is performed in the central pseudorapidity region (|η| < 0.8) for the transverse momentum p$_{T}$ > 0.3 GeV/c. Two separate pseudorapidity windows of width (δη) ranging from 0.2 to 0.8 are chosen symmetrically around η = 0. The multiplicity correlation strength (b$_{corr}$) is studied as a function of the pseudorapidity gap (η$_{gap}$) between the two windows as well as the width of these windows. The correlation strength is found to decrease with increasing η$_{gap}$ and shows a non-linear increase with δη. A sizable increase of the correlation strength with the collision energy, which cannot be explained exclusively by the increase of the mean multiplicity inside the windows, is observed. The correlation coefficient is also measured for multiplicities in different configurations of two azimuthal sectors selected within the symmetric FB η-windows. Two different contributions, the short-range (SR) and the long-range (LR), are observed. The energy dependence of b$_{corr}$ is found to be weak for the SR component while it is strong for the LR component. Moreover, the correlation coefficient is studied for particles belonging to various transverse momentum intervals chosen to have the same mean multiplicity. Both SR and LR contributions to b$_{corr}$ are found to increase with p$_{T}$ in this case. Results are compared to PYTHIA and PHOJET event generators and to a string-based phenomenological model. The observed dependencies of b$_{corr}$ add new constraints on phenomenological models.
Correlation strength $b_{\rm corr}$ for $\eta$-windows in $p_{\rm T}$ range $0.3-1.5$ (GeV/c) at $\sqrt{s}=0.9$ TeV.
Correlation strength $b_{\rm corr}$ for $\eta$-windows in $p_{\rm T}$ range $0.3-1.5$ (GeV/c) at $\sqrt{s}=2.76$ TeV.
Correlation strength $b_{\rm corr}$ for $\eta$-windows in $p_{\rm T}$ range $0.3-1.5$ (GeV/c) at $\sqrt{s}=7$ TeV.
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