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Open Access Publications from the University of California

Scholarly Works (18 results)

  • Article
  • Peer Reviewed
UC Berkeley Previously Published Works (2017)
The production of beauty hadrons was measured via semi-leptonic decays at mid-rapidity with the ALICE detector at the LHC in the transverse momentum interval 1
    Cover page: Measurement of electrons from beauty-hadron decays in p-Pb collisions at sNN=5.02 TeV and Pb-Pb collisions at sNN=2.76 TeV
    • Article
    • Peer Reviewed
    UC Berkeley Previously Published Works (2017)
    Electrons from heavy-flavour hadron decays (charm and beauty) were measured with the ALICE detector in Pb–Pb collisions at a centre-of-mass of energy sNN=2.76 TeV. The transverse momentum (pT) differential production yields at mid-rapidity were used to calculate the nuclear modification factor RAA in the interval 3
      Cover page: Measurement of the production of high-pT electrons from heavy-flavour hadron decays in Pb–Pb collisions at sNN=2.76 TeV
      • Article
      • Peer Reviewed
      UC Berkeley Previously Published Works (2017)
      The production cross sections for prompt charmed mesons D 0, D +, D ∗ + and Ds+ were measured at mid-rapidity in proton–proton collisions at a centre-of-mass energy s=7TeV with the ALICE detector at the Large Hadron Collider (LHC). D mesons were reconstructed from their decays D 0→ K -π+, D +→ K -π+π+, D ∗ +→ D 0π+, Ds++→K-K+π+, and their charge conjugates.With respect to previous measurements in the same rapidity region, the coverage in transverse momentum (pT) is extended and the uncertainties are reduced by a factor of about two. The accuracy on the estimated total c c ¯ production cross section is likewise improved. The measured pT-differential cross sections are compared with the results of three perturbative QCD calculations.
        Cover page: Measurement of D-meson production at mid-rapidity in pp collisions at s=7 TeV
        • Article
        • Peer Reviewed
        UC Berkeley Previously Published Works (2017)
        The W and Z boson production was measured via the muonic decay channel in proton-lead collisions at sNN=5.02 TeV at the Large Hadron Collider with the ALICE detector. The measurement covers backward (−4.46 < ycms < −2.96) and forward (2.03 < ycms < 3.53) rapidity regions, corresponding to Pb-going and p-going directions, respectively. The Z-boson production cross section, with dimuon invariant mass of 60 < mμμ < 120 GeV/c2 and muon transverse momentum (pTμ) larger than 20 GeV/c, is measured. The production cross section and charge asymmetry of muons from W-boson decays with pTμ > 10 GeV/c are determined. The results are compared to theoretical calculations both with and without including the nuclear modification of the parton distribution functions. The W-boson production is also studied as a function of the collision centrality: the cross section of muons from W-boson decays is found to scale with the average number of binary nucleon-nucleon collisions within uncertainties.[Figure not available: see fulltext.]
          Cover page: W and Z boson production in p-Pb collisions at sNN=5.02 TeV
          • Article
          • Peer Reviewed
          UC Berkeley Previously Published Works (2018)
          This letter presents the first measurement of jet mass in Pb–Pb and p–Pb collisions at sNN=2.76 TeV and sNN=5.02 TeV, respectively. Both the jet energy and the jet mass are expected to be sensitive to jet quenching in the hot Quantum Chromodynamics (QCD) matter created in nuclear collisions at collider energies. Jets are reconstructed from charged particles using the anti-kT jet algorithm and resolution parameter R=0.4. The jets are measured in the pseudorapidity range |ηjet|<0.5 and in three intervals of transverse momentum between 60 GeV/c and 120 GeV/c. The measurement of the jet mass in central Pb–Pb collisions is compared to the jet mass as measured in p–Pb reference collisions, to vacuum event generators, and to models including jet quenching. It is observed that the jet mass in central Pb–Pb collisions is consistent within uncertainties with p–Pb reference measurements. Furthermore, the measured jet mass in Pb–Pb collisions is not reproduced by the quenching models considered in this letter and is found to be consistent with PYTHIA expectations within systematic uncertainties.
            Cover page: First measurement of jet mass in Pb–Pb and p–Pb collisions at the LHC
            • Article
            • Peer Reviewed
            UC Berkeley Previously Published Works (2017)
            We present results on transverse momentum ([Formula: see text]) and rapidity ([Formula: see text]) differential production cross sections, mean transverse momentum and mean transverse momentum square of inclusive [Formula: see text] and [Formula: see text] at forward rapidity ([Formula: see text]) as well as [Formula: see text]-to-[Formula: see text] cross section ratios. These quantities are measured in pp collisions at center of mass energies [Formula: see text] and 13 TeV with the ALICE detector. Both charmonium states are reconstructed in the dimuon decay channel, using the muon spectrometer. A comprehensive comparison to inclusive charmonium cross sections measured at [Formula: see text], 7 and 8 TeV is performed. A comparison to non-relativistic quantum chromodynamics and fixed-order next-to-leading logarithm calculations, which describe prompt and non-prompt charmonium production respectively, is also presented. A good description of the data is obtained over the full [Formula: see text] range, provided that both contributions are summed. In particular, it is found that for [Formula: see text] GeV/c the non-prompt contribution reaches up to 50% of the total charmonium yield.
              Cover page: Energy dependence of forward-rapidity J/ψ and ψ(2S) production in pp collisions at the LHC
              • Article
              • Peer Reviewed
              UC Berkeley Previously Published Works (2017)
              In two-particle angular correlation measurements, jets give rise to a near-side peak, formed by particles associated to a higher-pT trigger particle. Measurements of these correlations as a function of pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the centrality and pT dependence of the shape of the near-side peak in the pT range 1
                Cover page: Evolution of the longitudinal and azimuthal structure of the near-side jet peak in Pb-Pb collisions at sNN=2.76 TeV
                • Article
                • Peer Reviewed
                UC Berkeley Previously Published Works (2017)
                The production of muons from heavy-flavour hadron decays in p–Pb collisions at sNN=5.02 TeV was studied for 2
                  Cover page: Production of muons from heavy-flavour hadron decays in p–Pb collisions at sNN=5.02&nbsp;TeV
                  • Article
                  • Peer Reviewed
                  UC Berkeley Previously Published Works (2017)
                  The transverse momentum distributions of the strange and double-strange hyperon resonances (Σ(1385)±, Ξ(1530)0) produced in p-Pb collisions at sNN=5.02 TeV were measured in the rapidity range -0.5
                    Cover page: Production of Σ(1385)± and Ξ(1530)0 in p–Pb collisions at sNN=5.02 TeV
                    • Article
                    • Peer Reviewed
                    UC Berkeley Previously Published Works (2017)
                    Two-particle angular correlations were measured in pp collisions at s=7 TeV for pions, kaons, protons, and lambdas, for all particle/anti-particle combinations in the pair. Data for mesons exhibit an expected peak dominated by effects associated with mini-jets and are well reproduced by general purpose Monte Carlo generators. However, for baryon–baryon and anti-baryon–anti-baryon pairs, where both particles have the same baryon number, a near-side anti-correlation structure is observed instead of a peak. This effect is interpreted in the context of baryon production mechanisms in the fragmentation process. It currently presents a challenge to Monte Carlo models and its origin remains an open question.
                      Cover page: Insight into particle production mechanisms via angular correlations of identified particles in pp collisions at s=7 TeV
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