| 1. |
- Abe, K., et al.
(författare)
-
J-PARC Neutrino Beamline Upgrade Technical Design Report
- 2019
-
Rapport (refereegranskat)abstract
- In this document, technical details of the upgrade plan of the J-PARC neutrino beamline for the extension of the T2K experiment are described. T2K has proposed to accumulate data corresponding to 2×1022 protons-on-target in the next decade, aiming at an initial observation of CP violation with 3σ or higher significance in the case of maximal CP violation. Methods to increase the neutrino beam intensity, which are necessary to achieve the proposed data increase, are described.
|
|
| 2. |
- Ankowski, A., et al.
(författare)
-
Energy reconstruction of electromagnetic showers from Ν0 decays with the ICARUS T600 liquid argon TPC
- 2010
-
Ingår i: Acta Physica Polonica, Series B.. - 1509-5770 .- 0587-4254. ; 41:1, s. 103-125
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss the ICARUS T600 detector capabilities in electromagnetic shower reconstruction through the analysis of a sample of 212 events, coming from the 2001 Pavia surface test run, of hadronic interactions leading to the production of π 0 mesons. Methods of shower energy and shower direction measurements were developed and the invariant mass of the photon pairs was reconstructed. The (γγ) invariant mass was found to be consistent with the value of the π 0 mass. The resolution of the reconstructed π 0 mass was found to be equal to 27.3%. An improved analysis, carried out in order to clean the full event sample from the events measured in the crowded environment, mostly due to the trigger conditions, gave a π 0 mass resolution of 16.1%, significantly better than the one evaluated for the full event sample. The trigger requirement of the coincidence of at least four photo-multiplier signals favored the selection of events with a strong pile up of cosmic ray tracks and interactions. Hence a number of candidate π 0 events were heavily contaminated by other tracks and had to be rejected. Monte Carlo simulations of events with π 0 production in hadronic and neutrino interactions confirmed the validity of the shower energy and shower direction reconstruction methods applied to the real data.
|
|
| 3. |
- Ankowski, A, et al.
(författare)
-
Energy reconstruction of electromagnetic showers from π0 decays with the ICARUS T600 liquid argon TPC
- 2010
-
Ingår i: Acta Physica Polonica B. - : Jagellonian University. - 0587-4254 .- 1509-5770. ; 41:1, s. 103-125
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss the ICARUS T600 detector capabilities in electromagnetic shower reconstruction through the analysis of a sample of 212 events, coming from the 2001 Pavia surface test run, of hadronic interactions leading to the production of π0 mesons. Methods of shower energy and shower direction measurements were developed and the invariant mass of the photon pairs was reconstructed. The (γ,γ) invariant mass was found to be consistent with the value of the π0 mass. The resolution of the reconstructed π0 mass was found to be equal to 27.3%. An improved analysis, carried out in order to clean the full event sample from the events measured in the crowded environment, mostly due to the trigger conditions, gave a π0 mass resolution of 16.1%, significantly better than the one evaluated for the full event sample. The trigger requirement of the coincidence of at least four photo-multiplier signals favored the selection of events with a strong pile up of cosmic ray tracks and interactions. Hence a number of candidate π0 events were heavily contaminated by other tracks and had to be rejected. Monte Carlo simulations of events with π0 production in hadronic and neutrino interactions confirmed the validity of the shower energy and shower direction reconstruction methods applied to the real data.
|
|
| 4. |
- Rubbia, C, et al.
(författare)
-
Underground operation of the ICARUS T600 LAr-TPC : first results
- 2011
-
Ingår i: Journal of Instrumentation. ; 6:07
-
Tidskriftsartikel (refereegranskat)abstract
- Important open questions are still present in fundamental Physics and Cosmology, like the nature of Dark Matter, the matter-antimatter asymmetry and the validity of the Standard Model of particle interactions. Addressing these questions requires a new generation of massive particle detectors to explore the subatomic and astrophysical worlds. ICARUS T600 is the first large mass (760 tons) example of a new generation of detectors able to combine the imaging capabilities of the old famous “bubble chamber” with the excellent energy measurement of huge electronic detectors. ICARUS T600 now operates at the Gran Sasso underground laboratory and is used to study cosmic rays, neutrino oscillations and the proton decay. The potential for doing physics of this novel telescope is presented through a few examples of neutrino interactions reconstructed with unprecedented detail. Detector design and early operation are also reported.
|
|
| 5. |
- Aleksandrov, D., et al.
(författare)
-
Halo excitations in fragmentation of He-6 at 240 MeV/u on carbon and lead targets
- 2000
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 669:1-2, s. 51-64
-
Tidskriftsartikel (refereegranskat)abstract
- Dissociation of a 240 MeV/u beam of He-6, incident on carbon and lead targets, has been studied in kinematically complete experiments to investigate low-lying excitation modes in the halo nucleus He-6. It is shown that alignment effects characterize the inelastic scattering and allow an unambiguous assignment of the spin of a narrow resonance observed in the excitation energy spectrum. The differential cross sections for the He-6 inelastic scattering on carbon and lead targets were deduced from the measured moments of the two neutrons and the a-particle. An analysis of these distributions shows that quadrupole and, possibly, monopole excitations characterize the hadronic interaction, while the dipole mode is dominating in Coulomb dissociation. Neither theoretically predicted new resonance states in He-6 nor nuclear excitation of a dipole mode were found. Direct evidence has been obtained for strong suppression of Coulornb post-acceleration in direct Coulomb breakup in a lead target.
|
|
| 6. |
- Aleksandrov, D., et al.
(författare)
-
Invariant mass spectrum and alpha-n correlation function studied in the fragmentation of He-6 on a carbon target
- 1998
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 633:2, s. 234-246
-
Tidskriftsartikel (refereegranskat)abstract
- Momentum distributions and invariant mass spectra from the breakup of He-6 ions with an energy of 240 MeV/u interacting with a carbon target have been studied. The data were used to extract information about the reaction mechanism which is influenced by the structure of He-6. It is found that the dominant reaction mechanism is a two-step process: knock out of one neutron followed by the decay of the He-5 resonance. The shape of the (alpha+n) two-body invariant mass spectrum is interpreted as mainly reflecting the 5He ground state which is a J(pi) = 3/2(-) resonance. However, no evidence for correlations between cu particles and neutrons is observed in the momentum widths of the distributions. It is demonstrated that a combined analysis of the two-body invariant mass spectrum and an appropriate correlation function may be used to determine the properties of the intermediate resonance. (C) 1998 Elsevier Science B.V.
|
|
| 7. |
- Chulkov, L. V., et al.
(författare)
-
Large spin alignment of the unbound He-5 fragment after fragmentation of 240 MeV/nucleon He-6
- 1997
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 79:2, s. 201-204
-
Tidskriftsartikel (refereegranskat)abstract
- Peripheral fragmentation of a 240 MeV/nucleon beam of the halo nucleus He-6 incident on carbon target has been studied in a kinematically complete experiment. It is found that one-neutron stripping to the unbound nucleus He-5 is the dominant fragmentation mechanism and that it leads to a spin alignment of He-5 in a plane perpendicular to the He-5 momentum vector. This is expected to be a common feature for all neutron halo nuclei.
|
|
| 8. |
- Markenroth, Karin, 1973, et al.
(författare)
-
He-8-He-6: a comparative study of nuclear fragmentation reactions
- 2001
-
Ingår i: Nuclear Physics A. - 0375-9474. ; 679:3-4, s. 462-480
-
Tidskriftsartikel (refereegranskat)abstract
- Dissociation of 227 MeV/u He-8 in a carbon target has been studied in kinematically complete experiments. The data include the relative energy spectrum, angular distributions in the neutron knock-out channel (He-6 + n) as well as diffractive dissociation and inelastic scattering into the (He-6 + 2n) channel. The data are compared with corresponding results from the well-known halo nucleus He-6. In both cases it is found that neutron knock-out is the: dominating reaction channel. The relative energy spectrum (He-6 + n) shows a structure, which is interpreted as being due to the I-pi = 3/2(-) resonance in the He-7 ground state with about equal contribution from its I-pi = 1/2(-) spin-orbit partner. The He-7 resonance shows a spin alignment similar to that observed in He-5, but with a smaller anisotropy indicating that the structure of the He-8 ground state is more complicated than that of He-6. The data in the (He-6 + 2n) channel were used to identify resonances in the excitation energy spectrum of He-8. If the spectrum is interpreted as two overlapping resonances, the spin-parity assignment for these is found to be 2(+) and 1(-), respectively.
|
|
