| 1. |
- Abelev, Betty, et al.
(author)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Journal article (peer-reviewed)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(author)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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In: Journal of High Energy Physics. - 1029-8479. ; :11
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Journal article (peer-reviewed)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Abelev, Betty, et al.
(author)
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Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC
- 2012
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In: Journal of High Energy Physics. - 1029-8479. ; :7
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Journal article (peer-reviewed)abstract
- We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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| 4. |
- Eriksson, Jonas, 1984, et al.
(author)
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Update of prevalence of self-reported allergic rhinitis and chronic nasal symptoms among adults in Sweden
- 2012
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In: The Clinical Respiratory Journal. - 1752-699X .- 1752-6981. ; 6:3, s. 159-168
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Journal article (peer-reviewed)abstract
- Background: Allergic rhinitis (AR) is the most common immunologic disease, and it renders a considerable burden on both sufferers and society. The prevalence of AR has been increasing worldwide over the past century. The aim of this study was to assess the present prevalence, risk factor patterns and comorbidity of self-reported AR and chronic nasal symptoms in different age groups in Stockholm, Sweden. Methods: A postal questionnaire was sent on two occasions, in 2006 to a population aged 30-80 years, randomly selected 10 years previously, and in 2007 to a randomly selected sample of subjects aged 20-69 years. The response rates were 83% and 68%, respectively, and in total, 9792 subjects participated. The questionnaire included questions on self-reported AR, asthma, respiratory and nasal symptoms and possible determinants. Results: The prevalence of self-reported AR was 28.0% (men 26.6%, women 29.1%, P<0.01) similar to 10 years previously and 33.6% in ages 30-40 years. Allergic heredity [odds ratio (OR) 4.76, confidence interval (CI) 95% 4.25-5.33], physician-diagnosed asthma (OR 5.29, CI 95% 4.49-6.24) and occupational exposure to dust, gases and fumes (OR 1.49, CI 95% 1.30-1.72) were determinants for AR. Prevalence of chronic nasal congestion was 16.1% and of chronic rhinorrhea 14.1%. Conclusions: As a basis for understanding the disease, as well as in planning and prioritising health-care resources, the study provides information about the current prevalence and determinants of self-reported AR and chronic nasal symptoms. Further, comparing with previous studies, the present study suggests that a plateau in the prevalence of AR may have been reached in Sweden. Please cite this paper as: Eriksson J, Ekerljung L, Rönmark E, Dahlén B, Ahlstedt S, Dahlén S-E and Lundbäck B. Update of prevalence of self-reported allergic rhinitis and chronic nasal symptoms among adults in Sweden
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| 5. |
- Hunter, Deidre A., et al.
(author)
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A Study of Two Dwarf Irregular Galaxies with Asymmetrical Star Formation Distributions
- 2018
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In: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 855:1
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Journal article (peer-reviewed)abstract
- Two dwarf irregular galaxies, DDO 187 and NGC 3738, exhibit a striking pattern of star formation: intense star formation is taking place in a large region occupying roughly half of the inner part of the optical galaxy. We use data on the H I distribution and kinematics and stellar images and colors to examine the properties of the environment in the high star formation rate (HSF) halves of the galaxies in comparison with the low star formation rate halves. We find that the pressure and gas density are higher on the HSF sides by 30%-70%. In addition we find in both galaxies that the H I velocity fields exhibit significant deviations from ordered rotation and there are large regions of high-velocity dispersion and multiple velocity components in the gas beyond the inner regions of the galaxies. The conditions in the HSF regions are likely the result of large-scale external processes affecting the internal environment of the galaxies and enabling the current star formation there.
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| 6. |
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