The inclusive production cross sections at forward rapidity of J/$\psi$, $\psi$(2S), $\Upsilon$(1S) and $\Upsilon$(2S) are measured in pp collisions at $\sqrt{s} = 7$ TeV with the ALICE detector at the LHC. The analysis is based in a data sample corresponding to an integrated luminosity of 1.35 pb$^{-1}$. Quarkonia are reconstructed in the dimuon-decay channel and the signal yields are evaluated by fitting the $\mu^+\mu^-$ invariant mass distributions. The differential production cross sections are measured as a function of the transverse momentum $p_{\rm T}$ and rapidity $y$, over the ranges $0 < p_{\rm T} < 20$ GeV/$c$ for J/$\psi$, $0 < p_{\rm T} < 12$ GeV/$c$ for all other resonances and for $2.5 < y < 4$. The measured cross sections integrated over $p_{\rm T}$ and $y$, and assuming unpolarized quarkonia, are: $\sigma_{J/\psi} = 6.69 \pm 0.04 \pm 0.63$ $\mu$b, $\sigma_{\psi^{\prime}} = 1.13 \pm 0.07 \pm 0.14$ $\mu$b, $\sigma_{\Upsilon{\rm(1S)}} = 54.2 \pm 5.0 \pm 6.7$ nb and $\sigma_{\Upsilon{\rm (2S)}} = 18.4 \pm 3.7 \pm 2.2$ nb, where the first uncertainty is statistical and the second one is systematic. The results are compared to measurements performed by other LHC experiments and to theoretical models.
Differential production cross sections of J/psi as a function of pT.
Differential production cross sections of J/psi as a function of rapidity.
integrated production cross section of J/psi.
The ratios of yields of anti-baryons to baryons probes the mechanisms of baryon-number transport. Results for $\bar{\rm p}/{\rm p}$, $\bar{\rm \Lambda}/{\rm \Lambda}$, $\rm\bar{\Xi}$$^{+}/{\rm \Xi}^{-}$ and $\rm\bar{\Omega}$$^{+}/{\rm \Omega}^{-}$ in pp collisions at $\sqrt{s} = 0.9$, 2.76 and 7 TeV, 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 $\bar{\rm p}/{\rm p}$, $\bar{\rm \Lambda}/{\rm \Lambda}$, $\rm\bar{\Xi}$$^{+}/{\rm \Xi^{-}}$ and $\rm\bar{\Omega}$$^{+}/{\rm \Omega^{-}}$, reaching values compatible with unity for $\sqrt{s} = 7$ TeV, complement the earlier $\bar{\rm p}/{\rm p}$ measurement of ALICE. These dependencies can be described by exchanges with the Regge-trajectory intercept of $\alpha_{\rm {J}} \approx 0.5$, which are suppressed with increasing rapidity interval ${\rm \Delta} y$. Any significant contribution of an exchange not suppressed at large ${\rm \Delta} y$ (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.
The ALICE collaboration at the CERN Large Hadron Collider reports the first measurement of the inclusive differential jet cross section at mid-rapidity in pp collisions at $\sqrt{s} = 2.76$ TeV, with integrated luminosity of 13.6 nb$^{-1}$. Jets are measured over the transverse momentum range 20 to 125 GeV/c and are corrected to the particle level. Calculations based on Next-to-Leading Order perturbative QCD are in good agreement with the measurements. The ratio of inclusive jet cross sections for jet radii $R = 0.2$ and $R = 0.4$ is reported, and is also well reproduced by a Next-to-Leading Order perturbative QCD calculation when hadronization effects are included.
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.
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.
pT-differential inclusive cross section in |y| < 0.5 for prompt D_s^+ meson production in pp collisions at sqrt(s) = 7 TeV.
pT-integrated inclusive cross section in |y| < 0.5 for prompt D_s^+ meson production in pp collisions at sqrt(s) = 7 TeV. The latter three systematic uncertainties arise from extrapolating the visible cross section to the full pT range, luminosity, and the branching ratio, respectively.
Ratio of D^+ to D^0 meson production cross sections in |y| < 0.5 as a function of pT.
Measurements of cross sections of inelastic and diffractive processes in proton--proton collisions at LHC energies were carried out with the ALICE detector. The fractions of diffractive processes in inelastic collisions were determined from a study of gaps in charged particle pseudorapidity distributions: for single diffraction (diffractive mass $M_X < 200$ GeV/$c^2$) $\sigma_{\rm SD}/\sigma_{\rm INEL} = 0.21 \pm 0.03, 0.20^{+0.07}_{-0.08}$, and $0.20^{+0.04}_{-0.07}$, respectively at centre-of-mass energies $\sqrt{s} = 0.9, 2.76$, and 7~TeV; for double diffraction (for a pseudorapidity gap $\Delta\eta > 3$) $\sigma_{\rm DD}/\sigma_{\rm INEL} = 0.11 \pm 0.03, 0.12 \pm 0.05$, and $0.12^{+0.05}_{-0.04}$, respectively at $\sqrt{s} = 0.9, 2.76$, and 7~TeV. To measure the inelastic cross section, beam properties were determined with van der Meer scans, and, using a simulation of diffraction adjusted to data, the following values were obtained: $\sigma_{\rm INEL} = 62.8^{+2.4}_{-4.0} (model) \pm 1.2 (lumi)$ mb at $\sqrt{s} =$ 2.76~TeV and $73.2^{+2.0}_{-4.6} (model) \pm 2.6 (lumi)$ mb at $\sqrt{s}$ = 7~TeV. The single- and double-diffractive cross sections were calculated combining relative rates of diffraction with inelastic cross sections. The results are compared to previous measurements at proton--antiproton and proton--proton colliders at lower energies, to measurements by other experiments at the LHC, and to theoretical models.
Production ratios of SD with $M_{X} < 200 GeV/c^2$ to INEL.
Production ratios of DD with $\Delta\eta >3$ to INEL.
Single diffraction cross-section for $M_{X} < 200 GeV/c^2$.
The first measurements of the invariant differential cross sections of inclusive $\pi^0$ and $\eta$ meson production at mid-rapidity in proton-proton collisions at $\sqrt{s}=0.9$ TeV and $\sqrt{s}=7$ TeV are reported. The $\pi^0$ measurement covers the ranges $0.4<p_T<7$ GeV/$c$ and $0.3<p_T<25$ GeV/$c$ for these two energies, respectively. The production of $\eta$ mesons was measured at $\sqrt{s}=7$ TeV in the range $0.4<p_T<15$ GeV/$c$. Next-to-Leading Order perturbative QCD calculations, which are consistent with the $\pi^0$ spectrum at $\sqrt{s}=0.9$ TeV, overestimate those of $\pi^0$ and $\eta$ mesons at $\sqrt{s}=7$ TeV, but agree with the measured $\eta/\pi^0$ ratio at $\sqrt{s}=7$ TeV.
The measured invariant differential section for inclusive PI0 production at a centre-of-mass energy of 7 TeV.
The measured invariant differential section for inclusive PI0 production at a centre-of-mass energy of 0.9 TeV.
The measured invariant differential section for inclusive ETA production at a centre-of-mass energy of 7 TeV.
The ALICE experiment has measured low-mass dimuon production in pp collisions at $\sqrt{s} = 7$ TeV in the dimuon rapidity region 2.5<y<4. The observed dimuon mass spectrum is described as a superposition of resonance decays ($\eta$, $\rho$, $\omega$, $\eta^{'}$, $\phi$) into muons and semi-leptonic decays of charmed mesons. The measured production cross sections for $\omega$ and $\phi$ are $\sigma_\omega$ (1<$p_{\rm T}$<5 GeV/$c$,2.5<y<4) = 5.28 $\pm$ 0.54 (stat) $\pm$ 0.50 (syst) mb and $\sigma_\phi$(1<$p_{\rm T}$<5 GeV/$c$,2.5<y<4)=0.940 $\pm$ 0.084 (stat) $\pm$ 0.078 (syst) mb. The differential cross sections $d^2\sigma/dy dp_{\rm T}$ are extracted as a function of $p_{\rm T}$ for $\omega$ and $\phi$. The ratio between the $\rho$ and $\omega$ cross section is obtained. Results for the $\phi$ are compared with other measurements at the same energy and with predictions by models.
Differential phi 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.
Differential omega 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.
Total phi cross section from the di-muon data. The first error is statistical, the second is a systematic error.
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