| 11. |
- Aamodt, K., et al.
(author)
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Elliptic Flow of Charged Particles in Pb-Pb Collisions at root s(NN)=2.76 TeV
- 2010
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In: Physical Review Letters. - 1079-7114. ; 105:25
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Journal article (peer-reviewed)abstract
- We report the first measurement of charged particle elliptic flow in Pb-Pb collisions at root s(NN) p = 2.76 TeV with the ALICE detector at the CERN Large Hadron Collider. The measurement is performed in the central pseudorapidity region (vertical bar eta vertical bar < 0.8) and transverse momentum range 0.2 < p(t) < 5.0 GeV/c. The elliptic flow signal v(2), measured using the 4-particle correlation method, averaged over transverse momentum and pseudorapidity is 0.087 +/- 0.002(stat) +/- 0.003(syst) in the 40%-50% centrality class. The differential elliptic flow v(2)(p(t)) reaches a maximum of 0.2 near p(t) = 3 GeV/c. Compared to RHIC Au-Au collisions at root s(NN) = 200 GeV, the elliptic flow increases by about 30%. Some hydrodynamic model predictions which include viscous corrections are in agreement with the observed increase.
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| 12. |
- Aamodt, K., et al.
(author)
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Femtoscopy of pp collisions at root s=0.9 and 7 TeV at the LHC with two-pion Bose-Einstein correlations
- 2011
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In: Physical Review D (Particles, Fields, Gravitation and Cosmology). - 1550-2368. ; 84:11
-
Journal article (peer-reviewed)abstract
- We report on the high statistics two-pion correlation functions from pp collisions at root s = 0.9 TeV and root s = 7 TeV, measured by the ALICE experiment at the Large Hadron Collider. The correlation functions as well as the extracted source radii scale with event multiplicity and pair momentum. When analyzed in the same multiplicity and pair transverse momentum range, the correlation is similar at the two collision energies. A three-dimensional femtoscopic analysis shows an increase of the emission zone with increasing event multiplicity as well as decreasing homogeneity lengths with increasing transverse momentum. The latter trend gets more pronounced as multiplicity increases. This suggests the development of space-momentum correlations, at least for collisions producing a high multiplicity of particles. We consider these trends in the context of previous femtoscopic studies in high-energy hadron and heavy-ion collisions and discuss possible underlying physics mechanisms. Detailed analysis of the correlation reveals an exponential shape in the outward and longitudinal directions, while the sideward remains a Gaussian. This is interpreted as a result of a significant contribution of strongly decaying resonances to the emission region shape. Significant nonfemtoscopic correlations are observed, and are argued to be the consequence of "mini-jet"-like structures extending to low p(t). They are well reproduced by the Monte-Carlo generators and seen also in pi(+)pi(-) correlations.
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| 13. |
- Aamodt, K., et al.
(author)
-
Strange particle production in proton-proton collisions at root s=0.9 TeV with ALICE at the LHC
- 2011
-
In: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:3
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Journal article (peer-reviewed)abstract
- The production of mesons containing strange quarks (K-S(0), phi) and both singly and doubly strange baryons (Lambda, (Lambda) over bar, and Xi(-) + (Xi) over bar (+)) are measured at mid-rapidity in pp collisions at root s = 0.9 TeV with the ALICE experiment at the LHC. The results are obtained from the analysis of about 250 k minimum bias events recorded in 2009. Measurements of yields (dN/dy) and transverse momentum spectra at mid-rapidity for inelastic pp collisions are presented. For mesons, we report yields (< dN/dy >) of 0.184 +/- 0.002(stat.) +/- 0.006(syst.) for K-S(0) and 0.021 +/- 0.004(stat.) +/- 0.003(syst.) for phi. For baryons, we find < dN/dy > = 0.048 +/- 0.001(stat.) +/- 0.004(syst.) for Lambda, 0.047 +/- 0.002(stat.) +/- 0.005(syst.) for (Lambda) over bar and 0.0101 +/- 0.0020(stat.) +/- 0.0009(syst.) for Xi(-) + (Xi) over bar (+). The results are also compared with predictions for identified particle spectra from QCD-inspired models and provide a baseline for comparisons with both future pp measurements at higher energies and heavy-ion collisions.
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| 14. |
- Aamodt, K., et al.
(author)
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Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at root s(NN)=2.76 TeV
- 2011
-
In: Physical Review Letters. - 1079-7114. ; 106:3
-
Journal article (peer-reviewed)abstract
- The centrality dependence of the charged-particle multiplicity density at midrapidity in Pb-Pb collisions at root s(NN) = 2: 76 TeV is presented. The charged-particle density normalized per participating nucleon pair increases by about a factor of 2 from peripheral (70%-80%) to central (0%-5%) collisions. The centrality dependence is found to be similar to that observed at lower collision energies. The data are compared with models based on different mechanisms for particle production in nuclear collisions.
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| 15. |
- Aamodt, K., et al.
(author)
-
Suppression of charged particle production at large transverse momentum in central Pb-Pb collisions at root s(NN)=2.76 TeV
- 2011
-
In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 696:1-2, s. 30-39
-
Journal article (peer-reviewed)abstract
- Inclusive transverse momentum spectra of primary charged particles in Pb-Pb collisions at root s(NN) = 2.76 TeV have been measured by the ALICE Collaboration at the LHC. The data are presented for central and peripheral collisions, corresponding to 0-5% and 70-80% of the hadronic Pb-Pb cross section. The measured charged particle spectra in |eta| < 0.8 and 0.3 < p(T) < 20 GeV/c are compared to the expectation in pp collisions at the same root s(NN), scaled by the number of underlying nucleon-nucleon collisions. The comparison is expressed in terms of the nuclear modification factor R-AA. The result indicates only weak medium effects (R-AA approximate to 0.7) in peripheral collisions. In central collisions, R-AA reaches a minimum of about 0.14 at p(T) = 6-7 GeV/c and increases significantly at larger p(T). The measured suppression of high-p(T) particles is stronger than that observed at lower collision energies, indicating that a very dense medium is formed in central Pb-Pb collisions at the LHC. (C) 2010 CERN. Published by Elsevier B.V. All rights reserved.
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| 16. |
- Aamodt, K., et al.
(author)
-
Two-pion Bose-Einstein correlations in central Pb-Pb collisions at root(NN)-N-S=2.76 TeV
- 2011
-
In: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 696:4, s. 328-337
-
Journal article (peer-reviewed)abstract
- The first measurement of two-pion Bose-Einstein correlations in central Pb-Pb collisions at root(NN)-N-S = 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. (C) 2010 CERN. Published by Elsevier B.V. All rights reserved.
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| 17. |
- Feroci, M., et al.
(author)
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The large observatory for x-ray timing
- 2014
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 9780819496126
-
Conference paper (peer-reviewed)abstract
- The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final downselection for a launch slot in 2022-2024. Thanks to the unprecedented combination of effective area and spectral resolution of its main instrument, LOFT will study the behaviour of matter under extreme conditions, such as the strong gravitational field in the innermost regions of accretion flows close to black holes and neutron stars, and the supranuclear densities in the interior of neutron stars. The science payload is based on a Large Area Detector (LAD, 10 m2 effective area, 2-30 keV, 240 eV spectral resolution, 1° collimated field of view) and a Wide Field Monitor (WFM, 2-50 keV, 4 steradian field of view, 1 arcmin source location accuracy, 300 eV spectral resolution). The WFM is equipped with an on-board system for bright events (e.g. GRB) localization. The trigger time and position of these events are broadcast to the ground within 30 s from discovery. In this paper we present the status of the mission at the end of its Phase A study.
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| 18. |
- De Angelis, A., et al.
(author)
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Science with e-ASTROGAM A space mission for MeV-GeV gamma-ray astrophysics
- 2018
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In: Journal of High Energy Astrophysics. - : Elsevier. - 2214-4048 .- 2214-4056. ; 19, s. 1-106
-
Journal article (peer-reviewed)abstract
- e-ASTROGAM ('enhanced ASTROGAM') is a breakthrough Observatory space mission, with a detector composed by a Silicon tracker, a calorimeter, and an anticoincidence system, dedicated to the study of the non-thermal Universe in the photon energy range from 0.3 MeV to 3 GeV - the lower energy limit can be pushed to energies as low as 150 keV for the tracker, and to 30 keV for calorimetric detection. The mission is based on an advanced space-proven detector technology, with unprecedented sensitivity, angular and energy resolution, combined with polarimetric capability. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources, elucidating the nature of their relativistic outflows and their effects on the surroundings. With a line sensitivity in the MeV energy range one to two orders of magnitude better than previous generation instruments, e-ASTROGAM will determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. The mission will provide unique data of significant interest to a broad astronomical community, complementary to powerful observatories such as LIGO-Virgo-GEO600-KAGRA, SKA, ALMA, E-ELT, TMT, LSST, JWST, Athena, CTA, IceCube, KM3NeT, and LISA.
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| 19. |
- Feroci, M., et al.
(author)
-
LOFT - The large observatory for x-ray timing
- 2012
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE - International Society for Optical Engineering. - 9780819491442 ; , s. 84432D-
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Conference paper (peer-reviewed)abstract
- The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultradense matter. These primary science goals will be addressed by a payload composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a collimated (<1 degree field of view) experiment operating in the energy range 2-50 keV, with a 10 m2 peak effective area and an energy resolution of 260 eV at 6 keV. The WFM will operate in the same energy range as the LAD, enabling simultaneous monitoring of a few-steradian wide field of view, with an angular resolution of <5 arcmin. The LAD and WFM experiments will allow us to investigate variability from submillisecond QPO's to yearlong transient outbursts. In this paper we report the current status of the project.
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| 20. |
- Ferrario, M., et al.
(author)
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IRIDE : Interdisciplinary research infrastructure based on dual electron linacs and lasers
- 2014
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In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 740, s. 138-146
-
Journal article (peer-reviewed)abstract
- This paper describes the scientific aims and potentials as well as the preliminary technical design of RUDE, an innovative tool for multi-disciplinary investigations in a wide field of scientific, technological and industrial applications. IRIDE will be a high intensity "particles factory", based on a combination of high duty cycle radio-frequency superconducting electron linacs and of high energy lasers. Conceived to provide unique research possibilities for particle physics, for condensed matter physics, chemistry and material science, for structural biology and industrial applications, IRIDE will open completely new research possibilities and advance our knowledge in many branches of science and technology. [RIDE is also supposed to be realized in subsequent stages of development depending on the assigned priorities.
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